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• (Not) The Sum of Its Parts: Relating Individual Video and Browsing Stimuli to Web Session QoE. Schleicher, Johannes; Wehner, Nikolas; Hoßfeld, Tobias; Seufert, Michael. In 16th International Conference on Quality of Multimedia Experience (QoMEX). Karlshamn, Sweden, 2024.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2024-3, address = {Karlshamn, Sweden}, author = {Schleicher, Johannes and Wehner, Nikolas and Hoßfeld, Tobias and Seufert, Michael}, booktitle = {16th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {(Not) The Sum of Its Parts: Relating Individual Video and Browsing Stimuli to Web Session QoE}, year = 2024 }

  %0 Conference Paper %1 info3-inproceedings-2024-3 %A Schleicher, Johannes %A Wehner, Nikolas %A Hoßfeld, Tobias %A Seufert, Michael %B 16th International Conference on Quality of Multimedia Experience (QoMEX) %C Karlshamn, Sweden %D 2024 %T (Not) The Sum of Its Parts: Relating Individual Video and Browsing Stimuli to Web Session QoE
• Investigation of Serverless Consumption and Performance in Multi-Access Edge Computing. TrungKien, Nguyen; Loh, Frank; TrungKiem, Nguyen; MinhChau, Nguyen; Huu Thanh, Nguyen; Hoßfeld, Tobias. In The 38th International Conference on Information Networking (ICOIN). 2024.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2024-1, author = {TrungKien, Nguyen and Loh, Frank and TrungKiem, Nguyen and MinhChau, Nguyen and Huu Thanh, Nguyen and Hoßfeld, Tobias}, booktitle = {The 38th International Conference on Information Networking (ICOIN)}, keywords = {sys:hidden:inproceedings}, month = {01}, title = {Investigation of Serverless Consumption and Performance in Multi-Access Edge Computing}, year = 2024 }

  %0 Conference Paper %1 info3-inproceedings-2024-1 %A TrungKien, Nguyen %A Loh, Frank %A TrungKiem, Nguyen %A MinhChau, Nguyen %A Huu Thanh, Nguyen %A Hoßfeld, Tobias %B The 38th International Conference on Information Networking (ICOIN) %D 2024 %T Investigation of Serverless Consumption and Performance in Multi-Access Edge Computing
• Investigation of Container Network Function Deployment Costs in the Edge Cloud. TrungKien, Nguyen; Simonovski, Filip; Loh, Frank; Hoßfeld, Tobias; Huu Thanh, Nguyen. In 27th Conference on Innovation in Clouds, Internet and Networks (ICIN). 2024.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2024-2, author = {TrungKien, Nguyen and Simonovski, Filip and Loh, Frank and Hoßfeld, Tobias and Huu Thanh, Nguyen}, booktitle = {27th Conference on Innovation in Clouds, Internet and Networks (ICIN)}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Investigation of Container Network Function Deployment Costs in the Edge Cloud}, year = 2024 }

  %0 Conference Paper %1 info3-inproceedings-2024-2 %A TrungKien, Nguyen %A Simonovski, Filip %A Loh, Frank %A Hoßfeld, Tobias %A Huu Thanh, Nguyen %B 27th Conference on Innovation in Clouds, Internet and Networks (ICIN) %D 2024 %T Investigation of Container Network Function Deployment Costs in the Edge Cloud

• Paving the Way for an Energy Efficient and Sustainable Future Internet of Things. Loh, Frank; Raffeck, Simon; Geißler, Stefan; Hoßfeld, Tobias. In KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023. 2023.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2023-12, author = {Loh, Frank and Raffeck, Simon and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Paving the Way for an Energy Efficient and Sustainable Future Internet of Things}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-12 %A Loh, Frank %A Raffeck, Simon %A Geißler, Stefan %A Hoßfeld, Tobias %B KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 %D 2023 %T Paving the Way for an Energy Efficient and Sustainable Future Internet of Things
• Serverless Computing Lifecycle Model for Edge Cloud Deployments. Nguyen, TrungKien; Loh, Frank; Nguyen, Tung; Doan, Duong; Huu Thanh, Nguyen; Hoßfeld, Tobias. In IEEE International Conference on Communications 2023 - GreenNet Workshop. 2023.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Serverless computing is a new cloud computing execution model. It offers little operational and administrative overhead, function activation on-demand, and significantly reduced resource consumption. For that reason, it is studied heavily in recent literature by means of handling incoming traffic, applicability for different tasks, and overall performance. Especially the introduction of states, where functionality is kept in CPU or memory can improve performance significantly. However, an in-depth analysis of the resource demand by among others, CPU and memory usage, latency, and energy consumption is still a blank spot in literature. To this end, we propose a serverless lifecycle model with intermediate states and deploy an image processing test setup in the edge cloud to test it. Furthermore, we measure important resource metrics of all states and state transitions of the model. This helps us to answer the question, whether keeping functions available in specific states of a serverless computing instance can improve performance without massive negative influence on the resource requirements.

  @inproceedings{info3-article-2023-4, abstract = {Serverless computing is a new cloud computing execution model. It offers little operational and administrative overhead, function activation on-demand, and significantly reduced resource consumption. For that reason, it is studied heavily in recent literature by means of handling incoming traffic, applicability for different tasks, and overall performance. Especially the introduction of states, where functionality is kept in CPU or memory can improve performance significantly. However, an in-depth analysis of the resource demand by among others, CPU and memory usage, latency, and energy consumption is still a blank spot in literature. To this end, we propose a serverless lifecycle model with intermediate states and deploy an image processing test setup in the edge cloud to test it. Furthermore, we measure important resource metrics of all states and state transitions of the model. This helps us to answer the question, whether keeping functions available in specific states of a serverless computing instance can improve performance without massive negative influence on the resource requirements.}, author = {Nguyen, TrungKien and Loh, Frank and Nguyen, Tung and Doan, Duong and Huu Thanh, Nguyen and Hoßfeld, Tobias}, booktitle = {IEEE International Conference on Communications 2023 - GreenNet Workshop}, keywords = {sys:hidden:inproceedings}, title = {Serverless Computing Lifecycle Model for Edge Cloud Deployments}, year = 2023 }

  %0 Conference Paper %1 info3-article-2023-4 %A Nguyen, TrungKien %A Loh, Frank %A Nguyen, Tung %A Doan, Duong %A Huu Thanh, Nguyen %A Hoßfeld, Tobias %B IEEE International Conference on Communications 2023 - GreenNet Workshop %D 2023 %T Serverless Computing Lifecycle Model for Edge Cloud Deployments %X Serverless computing is a new cloud computing execution model. It offers little operational and administrative overhead, function activation on-demand, and significantly reduced resource consumption. For that reason, it is studied heavily in recent literature by means of handling incoming traffic, applicability for different tasks, and overall performance. Especially the introduction of states, where functionality is kept in CPU or memory can improve performance significantly. However, an in-depth analysis of the resource demand by among others, CPU and memory usage, latency, and energy consumption is still a blank spot in literature. To this end, we propose a serverless lifecycle model with intermediate states and deploy an image processing test setup in the edge cloud to test it. Furthermore, we measure important resource metrics of all states and state transitions of the model. This helps us to answer the question, whether keeping functions available in specific states of a serverless computing instance can improve performance without massive negative influence on the resource requirements.
• NB-IoT vs. LTE-M: Measurement Study of the Energy Consumption of LPWAN Technologies. Vomhoff, Viktoria; Raffeck, Simon; Geißler, Stefan; Hoßfeld, Tobias. In 2023 IEEE International Conference on Communications Workshops (ICC Workshops). 2023.
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  @inproceedings{info3-inproceedings-2023-10, author = {Vomhoff, Viktoria and Raffeck, Simon and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {2023 IEEE International Conference on Communications Workshops (ICC Workshops)}, keywords = {can}, title = {NB-IoT vs. LTE-M: Measurement Study of the Energy Consumption of LPWAN Technologies}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-10 %A Vomhoff, Viktoria %A Raffeck, Simon %A Geißler, Stefan %A Hoßfeld, Tobias %B 2023 IEEE International Conference on Communications Workshops (ICC Workshops) %D 2023 %T NB-IoT vs. LTE-M: Measurement Study of the Energy Consumption of LPWAN Technologies
• Challenges of Serverless Deployment in Edge-MEC-Cloud. Nguyen, TrungKien; Loh, Frank; Hoßfeld, Tobias. In KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks 2023. 2023.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2023-6, author = {Nguyen, TrungKien and Loh, Frank and Hoßfeld, Tobias}, booktitle = {KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks 2023}, keywords = {sys:hidden:inproceedings}, title = {Challenges of Serverless Deployment in Edge-MEC-Cloud}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-6 %A Nguyen, TrungKien %A Loh, Frank %A Hoßfeld, Tobias %B KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks 2023 %D 2023 %T Challenges of Serverless Deployment in Edge-MEC-Cloud
• DBM: Decentralized Burst Mitigation for Periodic LoRa Devices using Self-Organizing Radio Access. Raffeck, Simon; Geißler, Stefan; Hoßfeld, Tobias. In ICC 2023 - IEEE International Conference on Communications. 2023.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2023-7, author = {Raffeck, Simon and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {ICC 2023 - IEEE International Conference on Communications}, keywords = {can}, title = {DBM: Decentralized Burst Mitigation for Periodic LoRa Devices using Self-Organizing Radio Access}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-7 %A Raffeck, Simon %A Geißler, Stefan %A Hoßfeld, Tobias %B ICC 2023 - IEEE International Conference on Communications %D 2023 %T DBM: Decentralized Burst Mitigation for Periodic LoRa Devices using Self-Organizing Radio Access
• Traffic-Adaptive Scheme for SDN Control Plane with Containerized Architecture. AnhKhoa, Dang; TrungKiem, Nguyen; TrungKien, Nguyen; NgocTuan, Nguyen; Huu Thanh, Nguyen. In 2023 17th International Conference on Ubiquitous Information Management and Communication (IMCOM). 2023.
  • [ Abstract ]
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  • [ EndNote ]
  Software-Defined Networking (SDN) is gaining attention for its flexibility in programmability. It enhances network configuration and provides global visibility for administrators via a single interface. However, the centralized nature of SDN exposes many issues in scalability and resiliency. In this paper, with the advent of cloud computing, we present a containerized architecture capable of fast scaling up and down based on traffic load for SDN control plane. With our novel traffic-adaptive algorithm, the results show that the proposed system is able to fit performance with high incoming new-flow requests and scale down underused controllers for resource efficiency.

  @inproceedings{info3-inproceedings-2023-3, abstract = {Software-Defined Networking (SDN) is gaining attention for its flexibility in programmability. It enhances network configuration and provides global visibility for administrators via a single interface. However, the centralized nature of SDN exposes many issues in scalability and resiliency. In this paper, with the advent of cloud computing, we present a containerized architecture capable of fast scaling up and down based on traffic load for SDN control plane. With our novel traffic-adaptive algorithm, the results show that the proposed system is able to fit performance with high incoming new-flow requests and scale down underused controllers for resource efficiency.}, author = {AnhKhoa, Dang and TrungKiem, Nguyen and TrungKien, Nguyen and NgocTuan, Nguyen and Huu Thanh, Nguyen}, booktitle = {2023 17th International Conference on Ubiquitous Information Management and Communication (IMCOM)}, keywords = {sys:hidden:inproceedings}, month = {01}, title = {Traffic-Adaptive Scheme for SDN Control Plane with Containerized Architecture}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-3 %A AnhKhoa, Dang %A TrungKiem, Nguyen %A TrungKien, Nguyen %A NgocTuan, Nguyen %A Huu Thanh, Nguyen %B 2023 17th International Conference on Ubiquitous Information Management and Communication (IMCOM) %D 2023 %T Traffic-Adaptive Scheme for SDN Control Plane with Containerized Architecture %X Software-Defined Networking (SDN) is gaining attention for its flexibility in programmability. It enhances network configuration and provides global visibility for administrators via a single interface. However, the centralized nature of SDN exposes many issues in scalability and resiliency. In this paper, with the advent of cloud computing, we present a containerized architecture capable of fast scaling up and down based on traffic load for SDN control plane. With our novel traffic-adaptive algorithm, the results show that the proposed system is able to fit performance with high incoming new-flow requests and scale down underused controllers for resource efficiency.
• Moving Down the Stack: Performance Evaluation of Packet Processing Technologies for Stateful Firewalls. Dietz, Katharina; Gray, Nicholas; Wolz, Manuel; Lorenz, Claas; Hoßfeld, Tobias; Seufert, Michael. In 34th IEEE/IFIP Network Operations and Management Symposium (NOMS). Miami, Florida, 2023.
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  @inproceedings{info3-inproceedings-2023-2, address = {Miami, Florida}, author = {Dietz, Katharina and Gray, Nicholas and Wolz, Manuel and Lorenz, Claas and Hoßfeld, Tobias and Seufert, Michael}, booktitle = {34th IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {ucn}, month = {05}, title = {Moving Down the Stack: Performance Evaluation of Packet Processing Technologies for Stateful Firewalls}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-2 %A Dietz, Katharina %A Gray, Nicholas %A Wolz, Manuel %A Lorenz, Claas %A Hoßfeld, Tobias %A Seufert, Michael %B 34th IEEE/IFIP Network Operations and Management Symposium (NOMS) %C Miami, Florida %D 2023 %T Moving Down the Stack: Performance Evaluation of Packet Processing Technologies for Stateful Firewalls
• Uplink-based Live Session Model for Stalling Prediction in Video Streaming. Loh, Frank; Pimpinella, Andrea; Geißler, Stefan; Hoßfeld, Tobias. In IEEE/IFIP Network Operations and Management Symposium (NOMS). 2023.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Today, video streaming is responsible for about 50 % of all Internet traffic worldwide. To cope with this massive amount of video streaming data, a major concern of network providers is the development of efficient traffic monitoring and management techniques. However, fast and efficient monitoring which leads to intelligent management decisions is becoming highly resource intense and complex, due to the steady increase of the number of streamed videos and the quality of the streamed content. Considering HTTP adaptive streaming applications, we present a simple machine learning free, uplink request based approach to estimate drops in the video playback buffer. These drops are the first indicator leading to quality impairment events like downwards quality changes or stalling. With our approach, instead of analyzing thousands of encrypted packets in the network, we only need to consider one single packet every 5 s - 10 s on average, depending on the video chunk size and independently of the played resolution. Nevertheless, we are able to detect nearly all stalling events or consider a trade-off between stalling detection recall and false positives. Our approach can be implemented completely moving average based, thus not requiring any parameter setup or other expert knowledge. Due to its simplicity, it can be deployed on any access point to collect streaming quality information that is useful for active network management and intelligent resource provisioning but also in a data center to analyze a massive number of parallel video flows

  @inproceedings{info3-inproceedings-2023-16, abstract = {Today, video streaming is responsible for about 50 % of all Internet traffic worldwide. To cope with this massive amount of video streaming data, a major concern of network providers is the development of efficient traffic monitoring and management techniques. However, fast and efficient monitoring which leads to intelligent management decisions is becoming highly resource intense and complex, due to the steady increase of the number of streamed videos and the quality of the streamed content. Considering HTTP adaptive streaming applications, we present a simple machine learning free, uplink request based approach to estimate drops in the video playback buffer. These drops are the first indicator leading to quality impairment events like downwards quality changes or stalling. With our approach, instead of analyzing thousands of encrypted packets in the network, we only need to consider one single packet every 5 s - 10 s on average, depending on the video chunk size and independently of the played resolution. Nevertheless, we are able to detect nearly all stalling events or consider a trade-off between stalling detection recall and false positives. Our approach can be implemented completely moving average based, thus not requiring any parameter setup or other expert knowledge. Due to its simplicity, it can be deployed on any access point to collect streaming quality information that is useful for active network management and intelligent resource provisioning but also in a data center to analyze a massive number of parallel video flows}, author = {Loh, Frank and Pimpinella, Andrea and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Uplink-based Live Session Model for Stalling Prediction in Video Streaming}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-16 %A Loh, Frank %A Pimpinella, Andrea %A Geißler, Stefan %A Hoßfeld, Tobias %B IEEE/IFIP Network Operations and Management Symposium (NOMS) %D 2023 %T Uplink-based Live Session Model for Stalling Prediction in Video Streaming %X Today, video streaming is responsible for about 50 % of all Internet traffic worldwide. To cope with this massive amount of video streaming data, a major concern of network providers is the development of efficient traffic monitoring and management techniques. However, fast and efficient monitoring which leads to intelligent management decisions is becoming highly resource intense and complex, due to the steady increase of the number of streamed videos and the quality of the streamed content. Considering HTTP adaptive streaming applications, we present a simple machine learning free, uplink request based approach to estimate drops in the video playback buffer. These drops are the first indicator leading to quality impairment events like downwards quality changes or stalling. With our approach, instead of analyzing thousands of encrypted packets in the network, we only need to consider one single packet every 5 s - 10 s on average, depending on the video chunk size and independently of the played resolution. Nevertheless, we are able to detect nearly all stalling events or consider a trade-off between stalling detection recall and false positives. Our approach can be implemented completely moving average based, thus not requiring any parameter setup or other expert knowledge. Due to its simplicity, it can be deployed on any access point to collect streaming quality information that is useful for active network management and intelligent resource provisioning but also in a data center to analyze a massive number of parallel video flows
• Machine Learning Based Study of QoE Metrics in Twitch. tv Live Streaming. Loh, Frank; Hildebrand, Kathrin; Wamser, Florian; Geißler, Stefan; Hoßfeld, Tobias. In IEEE/IFIP Network Operations and Management Symposium (NOMS). 2023.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Video streaming generates most network traffic in today’s Internet. For that reason, video on demand streaming is researched heavily in recent years, and many traffic monitoring mechanisms, flow and stream models, and models to predict the user perceived quality are well established. However, the quickly growing live streaming sector is not considered in these Quality of Experience models and not even the relation between network traffic and playback quality has been studied so far, forming a gap in literature. For that reason, we investigate Twitch.tv streaming as one of the largest live streaming platforms based on a large dataset and investigate the possibility to predict live streaming quality based on uplink request information. We apply approaches that are well studied for on demand streaming to predict quality changes, playback quality, and video interruption events as the most important metrics impairing user perceived quality. In this context, we answer whether these models are suitable for live streaming, if small changes are sufficient for satisfactory prediction results, or if fundamental changes and new models are required.

  @inproceedings{info3-inproceedings-2023-17, abstract = {Video streaming generates most network traffic in today’s Internet. For that reason, video on demand streaming is researched heavily in recent years, and many traffic monitoring mechanisms, flow and stream models, and models to predict the user perceived quality are well established. However, the quickly growing live streaming sector is not considered in these Quality of Experience models and not even the relation between network traffic and playback quality has been studied so far, forming a gap in literature. For that reason, we investigate Twitch.tv streaming as one of the largest live streaming platforms based on a large dataset and investigate the possibility to predict live streaming quality based on uplink request information. We apply approaches that are well studied for on demand streaming to predict quality changes, playback quality, and video interruption events as the most important metrics impairing user perceived quality. In this context, we answer whether these models are suitable for live streaming, if small changes are sufficient for satisfactory prediction results, or if fundamental changes and new models are required.}, author = {Loh, Frank and Hildebrand, Kathrin and Wamser, Florian and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Machine Learning Based Study of QoE Metrics in Twitch. tv Live Streaming}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-17 %A Loh, Frank %A Hildebrand, Kathrin %A Wamser, Florian %A Geißler, Stefan %A Hoßfeld, Tobias %B IEEE/IFIP Network Operations and Management Symposium (NOMS) %D 2023 %T Machine Learning Based Study of QoE Metrics in Twitch. tv Live Streaming %X Video streaming generates most network traffic in today’s Internet. For that reason, video on demand streaming is researched heavily in recent years, and many traffic monitoring mechanisms, flow and stream models, and models to predict the user perceived quality are well established. However, the quickly growing live streaming sector is not considered in these Quality of Experience models and not even the relation between network traffic and playback quality has been studied so far, forming a gap in literature. For that reason, we investigate Twitch.tv streaming as one of the largest live streaming platforms based on a large dataset and investigate the possibility to predict live streaming quality based on uplink request information. We apply approaches that are well studied for on demand streaming to predict quality changes, playback quality, and video interruption events as the most important metrics impairing user perceived quality. In this context, we answer whether these models are suitable for live streaming, if small changes are sufficient for satisfactory prediction results, or if fundamental changes and new models are required.
• Understanding the Performance of Different Packet Reception and Timestamping Methods in Linux. Grigorjew, Alexej; Schumann, Lukas Kilian; Diederich, Philip; Hoßfeld, Tobias; Kellerer, Wolfgang. In WueWoWAS’23 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks. 2023.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  This document briefly presents some renowned packet reception techniques for network packets in Linux systems. Further, it compares their performance when measuring packet timestamps with respect to throughput and accuracy. Both software and hardware timestamps are compared, and various parameters are examined, including frame size, link speed, network interface card, and CPU load. The results indicate that hardware timestamping offers significantly better accuracy with no downsides, and that packet reception techniques that avoid system calls offer superior measurement throughput.

  @inproceedings{info3-inproceedings-2023-11, abstract = {This document briefly presents some renowned packet reception techniques for network packets in Linux systems. Further, it compares their performance when measuring packet timestamps with respect to throughput and accuracy. Both software and hardware timestamps are compared, and various parameters are examined, including frame size, link speed, network interface card, and CPU load. The results indicate that hardware timestamping offers significantly better accuracy with no downsides, and that packet reception techniques that avoid system calls offer superior measurement throughput.}, author = {Grigorjew, Alexej and Schumann, Lukas Kilian and Diederich, Philip and Hoßfeld, Tobias and Kellerer, Wolfgang}, booktitle = {WueWoWAS'23 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks}, keywords = {appaware2}, month = {06}, title = {Understanding the Performance of Different Packet Reception and Timestamping Methods in Linux}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-11 %A Grigorjew, Alexej %A Schumann, Lukas Kilian %A Diederich, Philip %A Hoßfeld, Tobias %A Kellerer, Wolfgang %B WueWoWAS'23 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks %D 2023 %T Understanding the Performance of Different Packet Reception and Timestamping Methods in Linux %X This document briefly presents some renowned packet reception techniques for network packets in Linux systems. Further, it compares their performance when measuring packet timestamps with respect to throughput and accuracy. Both software and hardware timestamps are compared, and various parameters are examined, including frame size, link speed, network interface card, and CPU load. The results indicate that hardware timestamping offers significantly better accuracy with no downsides, and that packet reception techniques that avoid system calls offer superior measurement throughput.
• Resilience in Time-Sensitive Networking: An Overview and Open Research Directions. Grigorjew, Alexej; Geißler, Stefan; Diederich, Philip; Hoßfeld, Tobias; Kellerer, Wolfgang. In 2023 13th International Workshop on Resilient Networks Design and Modeling (RNDM). 2023.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Time-Sensitive Networking (TSN) puts stringent requirements on its devices to provide deterministic services over Ethernet-based networks. Resilience is an important attribute for TSN to achieve dependable time-sensitive data transmission. Existing literature on resilience of TSN mostly focuses on a particular subset of TSN mechanisms for resilience analysis. This paper takes an overall systems viewpoint and analyzes the resilience in TSN systems provided by the interaction of multiple mechanisms. It discusses their dependencies, possible faults, and possible mitigations of a selected subset of standards. Thereby, it highlights open challenges for future research directions.

  @inproceedings{info3-inproceedings-2023-13, abstract = {Time-Sensitive Networking (TSN) puts stringent requirements on its devices to provide deterministic services over Ethernet-based networks. Resilience is an important attribute for TSN to achieve dependable time-sensitive data transmission. Existing literature on resilience of TSN mostly focuses on a particular subset of TSN mechanisms for resilience analysis. This paper takes an overall systems viewpoint and analyzes the resilience in TSN systems provided by the interaction of multiple mechanisms. It discusses their dependencies, possible faults, and possible mitigations of a selected subset of standards. Thereby, it highlights open challenges for future research directions.}, author = {Grigorjew, Alexej and Geißler, Stefan and Diederich, Philip and Hoßfeld, Tobias and Kellerer, Wolfgang}, booktitle = {2023 13th International Workshop on Resilient Networks Design and Modeling (RNDM)}, keywords = {appaware2}, month = {09}, title = {Resilience in Time-Sensitive Networking: An Overview and Open Research Directions}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-13 %A Grigorjew, Alexej %A Geißler, Stefan %A Diederich, Philip %A Hoßfeld, Tobias %A Kellerer, Wolfgang %B 2023 13th International Workshop on Resilient Networks Design and Modeling (RNDM) %D 2023 %T Resilience in Time-Sensitive Networking: An Overview and Open Research Directions %X Time-Sensitive Networking (TSN) puts stringent requirements on its devices to provide deterministic services over Ethernet-based networks. Resilience is an important attribute for TSN to achieve dependable time-sensitive data transmission. Existing literature on resilience of TSN mostly focuses on a particular subset of TSN mechanisms for resilience analysis. This paper takes an overall systems viewpoint and analyzes the resilience in TSN systems provided by the interaction of multiple mechanisms. It discusses their dependencies, possible faults, and possible mitigations of a selected subset of standards. Thereby, it highlights open challenges for future research directions.
• Collision and Energy Efficiency Assessment of LoRaWANs with Cluster-Based Gateway Placement. Loh, Frank; Baur, Carina; Geißler, Stefan; ElBakoury, Hesham; Hoßfeld, Tobias. In IEEE International Conference on Communications Workshops. 2023.
  • [ Abstract ]
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  • [ EndNote ]
  LoRaWAN is one of the most prominent low power wide area network technologies. It offers long transmission distances with little energy consumption. The drawback is potential message collision. For that reason, recent literature discusses different alternatives to the currently used random channel access suffering from many message collisions and evaluates improvement possibilities. This is of major interest for network operators to future-proof LoRaWAN quality. One approach to reduce collision probability is cell size management via intelligent gateway placement. For that reason, this work presents an exhaustive study for k-means based clustering to distribute gateways. Different network quality metrics, namely full coverage for all sensors, collision probability, and energy efficiency, are evaluated. Thus, the contribution is a simple and scalable gateway placement approach for LoRaWAN. The performance evaluation shows a trade-off between placed gateways and energy efficiency. Furthermore, with reasonable runtime for large-scale networks, the clustering based approach is a viable solution for future network pre-planning or even final placement.

  @inproceedings{info3-inproceedings-2023-18, abstract = {LoRaWAN is one of the most prominent low power wide area network technologies. It offers long transmission distances with little energy consumption. The drawback is potential message collision. For that reason, recent literature discusses different alternatives to the currently used random channel access suffering from many message collisions and evaluates improvement possibilities. This is of major interest for network operators to future-proof LoRaWAN quality. One approach to reduce collision probability is cell size management via intelligent gateway placement. For that reason, this work presents an exhaustive study for k-means based clustering to distribute gateways. Different network quality metrics, namely full coverage for all sensors, collision probability, and energy efficiency, are evaluated. Thus, the contribution is a simple and scalable gateway placement approach for LoRaWAN. The performance evaluation shows a trade-off between placed gateways and energy efficiency. Furthermore, with reasonable runtime for large-scale networks, the clustering based approach is a viable solution for future network pre-planning or even final placement.}, author = {Loh, Frank and Baur, Carina and Geißler, Stefan and ElBakoury, Hesham and Hoßfeld, Tobias}, booktitle = {IEEE International Conference on Communications Workshops}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Collision and Energy Efficiency Assessment of LoRaWANs with Cluster-Based Gateway Placement}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-18 %A Loh, Frank %A Baur, Carina %A Geißler, Stefan %A ElBakoury, Hesham %A Hoßfeld, Tobias %B IEEE International Conference on Communications Workshops %D 2023 %T Collision and Energy Efficiency Assessment of LoRaWANs with Cluster-Based Gateway Placement %X LoRaWAN is one of the most prominent low power wide area network technologies. It offers long transmission distances with little energy consumption. The drawback is potential message collision. For that reason, recent literature discusses different alternatives to the currently used random channel access suffering from many message collisions and evaluates improvement possibilities. This is of major interest for network operators to future-proof LoRaWAN quality. One approach to reduce collision probability is cell size management via intelligent gateway placement. For that reason, this work presents an exhaustive study for k-means based clustering to distribute gateways. Different network quality metrics, namely full coverage for all sensors, collision probability, and energy efficiency, are evaluated. Thus, the contribution is a simple and scalable gateway placement approach for LoRaWAN. The performance evaluation shows a trade-off between placed gateways and energy efficiency. Furthermore, with reasonable runtime for large-scale networks, the clustering based approach is a viable solution for future network pre-planning or even final placement.
• Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation. Geißler, Stefan; Lange, Stanislav; Hasslinger, Gerhard; Tran-Gia, Phuoc; Hoßfeld, Tobias. In 34th International Teletraffic Congress (ITC). Shenzhen, China. 2023.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2023-1, author = {Geißler, Stefan and Lange, Stanislav and Hasslinger, Gerhard and Tran-Gia, Phuoc and Hoßfeld, Tobias}, booktitle = {34th International Teletraffic Congress (ITC). Shenzhen, China}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-1 %A Geißler, Stefan %A Lange, Stanislav %A Hasslinger, Gerhard %A Tran-Gia, Phuoc %A Hoßfeld, Tobias %B 34th International Teletraffic Congress (ITC). Shenzhen, China %D 2023 %T Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation
• Developing a Library of Problem Scenarios for Time-Sensitive and Real-Time Networking. Grigorjew, Alexej; Vomhoff, Viktoria; Geißler, Stefan; Diederich, Philip; Hoßfeld, Tobias; Kellerer, Wolfgang. In International Conference on Networked Systems 2023 (NetSys). 2023.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  The lack of realistic problem instances is one of the major challenges when it comes to evaluating and comparing mechanisms and approaches in the area of real-time networking. To this end, we aim at establishing a library of general as well as use case specific scenarios including different network topologies and traffic streams with the goal of promoting comparability among research works and facilitate the development of innovative approaches. We present our foundational framework for the generation of these synthetic problem instances and call on the community to contribute their experiences and insights.

  @inproceedings{info3-inproceedings-2023-15, abstract = {The lack of realistic problem instances is one of the major challenges when it comes to evaluating and comparing mechanisms and approaches in the area of real-time networking. To this end, we aim at establishing a library of general as well as use case specific scenarios including different network topologies and traffic streams with the goal of promoting comparability among research works and facilitate the development of innovative approaches. We present our foundational framework for the generation of these synthetic problem instances and call on the community to contribute their experiences and insights.}, author = {Grigorjew, Alexej and Vomhoff, Viktoria and Geißler, Stefan and Diederich, Philip and Hoßfeld, Tobias and Kellerer, Wolfgang}, booktitle = {International Conference on Networked Systems 2023 (NetSys)}, keywords = {appaware2}, month = {09}, title = {Developing a Library of Problem Scenarios for Time-Sensitive and Real-Time Networking}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-15 %A Grigorjew, Alexej %A Vomhoff, Viktoria %A Geißler, Stefan %A Diederich, Philip %A Hoßfeld, Tobias %A Kellerer, Wolfgang %B International Conference on Networked Systems 2023 (NetSys) %D 2023 %T Developing a Library of Problem Scenarios for Time-Sensitive and Real-Time Networking %X The lack of realistic problem instances is one of the major challenges when it comes to evaluating and comparing mechanisms and approaches in the area of real-time networking. To this end, we aim at establishing a library of general as well as use case specific scenarios including different network topologies and traffic streams with the goal of promoting comparability among research works and facilitate the development of innovative approaches. We present our foundational framework for the generation of these synthetic problem instances and call on the community to contribute their experiences and insights.
• Demystifying User-based Active Learning for Network Monitoring Tasks. Dietz, Katharina; Wehner, Nikolas; Casas, Pedro; Hoßfeld, Tobias; Seufert, Michael. In 2nd Workshop on Machine Learning & Networking (MaLeNe) as part of NetSys’23. Potsdam, Germany, 2023.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2023-9, address = {Potsdam, Germany}, author = {Dietz, Katharina and Wehner, Nikolas and Casas, Pedro and Hoßfeld, Tobias and Seufert, Michael}, booktitle = {2nd Workshop on Machine Learning & Networking (MaLeNe) as part of NetSys'23}, keywords = {ucn}, month = {09}, title = {Demystifying User-based Active Learning for Network Monitoring Tasks}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-9 %A Dietz, Katharina %A Wehner, Nikolas %A Casas, Pedro %A Hoßfeld, Tobias %A Seufert, Michael %B 2nd Workshop on Machine Learning & Networking (MaLeNe) as part of NetSys'23 %C Potsdam, Germany %D 2023 %T Demystifying User-based Active Learning for Network Monitoring Tasks
• Accurate Live Visualization of Packet Delays, Inter-Arrival Times, and Burstiness for Real-Time Networks. Grigorjew, Alexej; Geißler, Stefan; Ziegler, Maximilian; Schumann, Lukas Kilian; Diederich, Philip; Hock, David; Hoßfeld, Tobias; Kellerer, Wolfgang. In International Conference on Networked Systems 2023 (NetSys). 2023.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  In this demonstration, a live delay and traffic volume visualization is presented. It is created with consumer off-the-shelf components, provides sub-microsecond accuracy, and provides sufficient performance for line rate measurements without sampling. The tool can help to accelerate the development and operation of real-time networks.

  @inproceedings{info3-inproceedings-2023-14, abstract = {In this demonstration, a live delay and traffic volume visualization is presented. It is created with consumer off-the-shelf components, provides sub-microsecond accuracy, and provides sufficient performance for line rate measurements without sampling. The tool can help to accelerate the development and operation of real-time networks.}, author = {Grigorjew, Alexej and Geißler, Stefan and Ziegler, Maximilian and Schumann, Lukas Kilian and Diederich, Philip and Hock, David and Hoßfeld, Tobias and Kellerer, Wolfgang}, booktitle = {International Conference on Networked Systems 2023 (NetSys)}, keywords = {kosinu5}, month = {09}, title = {Accurate Live Visualization of Packet Delays, Inter-Arrival Times, and Burstiness for Real-Time Networks}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-14 %A Grigorjew, Alexej %A Geißler, Stefan %A Ziegler, Maximilian %A Schumann, Lukas Kilian %A Diederich, Philip %A Hock, David %A Hoßfeld, Tobias %A Kellerer, Wolfgang %B International Conference on Networked Systems 2023 (NetSys) %D 2023 %T Accurate Live Visualization of Packet Delays, Inter-Arrival Times, and Burstiness for Real-Time Networks %X In this demonstration, a live delay and traffic volume visualization is presented. It is created with consumer off-the-shelf components, provides sub-microsecond accuracy, and provides sufficient performance for line rate measurements without sampling. The tool can help to accelerate the development and operation of real-time networks.
• Explainable Data-Driven QoE Modelling using XAI. Wehner, Nikolas; Seufert, Anika; Hoßfeld, Tobias; Seufert, Michael. In 15th International Conference on Quality of Multimedia Experience (QoMEX). Ghent, Belgium, 2023.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Data-driven QoE modelling using Machine Learning (ML) allows to reduce the modelling bias and to continuously integrate new QoE results into the QoE model, which can improve its generalizability. The downside is that the majority of ML models are black-box models, which prevent to obtain insights about QoE influence factors and their fundamental relationships that are highly relevant for researchers and providers of services and networks. However, recent advances in the field of eXplainable Artificial Intelligence (XAI) resolve these issues. Thus, XAI allows to benefit from data-driven QoE modelling to obtain generalizable QoE models, and at the same time to understand what QoE factors are relevant and how they affect the QoE score. In this work, we showcase the feasibility of explainable data-driven QoE modelling for video streaming, since video streaming QoE has been well researched, and thus, allows us to validate our results. Finally, we discuss opportunities and challenges of deploying XAI for QoE modelling.

  @inproceedings{info3-inproceedings-2023-4, abstract = {Data-driven QoE modelling using Machine Learning (ML) allows to reduce the modelling bias and to continuously integrate new QoE results into the QoE model, which can improve its generalizability. The downside is that the majority of ML models are black-box models, which prevent to obtain insights about QoE influence factors and their fundamental relationships that are highly relevant for researchers and providers of services and networks. However, recent advances in the field of eXplainable Artificial Intelligence (XAI) resolve these issues. Thus, XAI allows to benefit from data-driven QoE modelling to obtain generalizable QoE models, and at the same time to understand what QoE factors are relevant and how they affect the QoE score. In this work, we showcase the feasibility of explainable data-driven QoE modelling for video streaming, since video streaming QoE has been well researched, and thus, allows us to validate our results. Finally, we discuss opportunities and challenges of deploying XAI for QoE modelling.}, address = {Ghent, Belgium}, author = {Wehner, Nikolas and Seufert, Anika and Hoßfeld, Tobias and Seufert, Michael}, booktitle = {15th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ucn}, month = {06}, title = {Explainable Data-Driven QoE Modelling using XAI}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-4 %A Wehner, Nikolas %A Seufert, Anika %A Hoßfeld, Tobias %A Seufert, Michael %B 15th International Conference on Quality of Multimedia Experience (QoMEX) %C Ghent, Belgium %D 2023 %T Explainable Data-Driven QoE Modelling using XAI %X Data-driven QoE modelling using Machine Learning (ML) allows to reduce the modelling bias and to continuously integrate new QoE results into the QoE model, which can improve its generalizability. The downside is that the majority of ML models are black-box models, which prevent to obtain insights about QoE influence factors and their fundamental relationships that are highly relevant for researchers and providers of services and networks. However, recent advances in the field of eXplainable Artificial Intelligence (XAI) resolve these issues. Thus, XAI allows to benefit from data-driven QoE modelling to obtain generalizable QoE models, and at the same time to understand what QoE factors are relevant and how they affect the QoE score. In this work, we showcase the feasibility of explainable data-driven QoE modelling for video streaming, since video streaming QoE has been well researched, and thus, allows us to validate our results. Finally, we discuss opportunities and challenges of deploying XAI for QoE modelling.
• On the Validity of Credit-Based Shaper Delay Guarantees in Decentralized Reservation Protocols. Maile, Lisa; Voitlein, Dominik; Grigorjew, Alexej; Hielscher, Kai-Steffen J.; German, Reinhard. In 31st International Conference on Real-Time Networks and Systems. 2023.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Resource reservation is a fundamental mechanism for ensuring quality of service in time-sensitive networks, which can be decentralized by using reservation protocols. In the Ethernet technology Time-Sensitive Networking, this has been proposed in conjunction with the Credit-Based Shaper. For the reservation, the standards assume a maximum worst-case latency bound at each hop. However, we will show through formal analysis and simulation that these worst-case latency bounds are not safe. To face this, we propose an extension to the current standards to allow the reservation of time-sensitive traffic with reliable latency guarantees. The effectiveness of our approach is demonstrated through simulations of both synthetic and industrial networks. Finally, by providing additional information about neighboring devices, we could further increase the maximum reservable traffic by up to 20% in our test cases.

  @inproceedings{info3-inproceedings-2023-5, abstract = {Resource reservation is a fundamental mechanism for ensuring quality of service in time-sensitive networks, which can be decentralized by using reservation protocols. In the Ethernet technology Time-Sensitive Networking, this has been proposed in conjunction with the Credit-Based Shaper. For the reservation, the standards assume a maximum worst-case latency bound at each hop. However, we will show through formal analysis and simulation that these worst-case latency bounds are not safe. To face this, we propose an extension to the current standards to allow the reservation of time-sensitive traffic with reliable latency guarantees. The effectiveness of our approach is demonstrated through simulations of both synthetic and industrial networks. Finally, by providing additional information about neighboring devices, we could further increase the maximum reservable traffic by up to 20% in our test cases.}, author = {Maile, Lisa and Voitlein, Dominik and Grigorjew, Alexej and Hielscher, Kai-Steffen J. and German, Reinhard}, booktitle = {31st International Conference on Real-Time Networks and Systems}, keywords = {can}, month = {06}, title = {On the Validity of Credit-Based Shaper Delay Guarantees in Decentralized Reservation Protocols}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-5 %A Maile, Lisa %A Voitlein, Dominik %A Grigorjew, Alexej %A Hielscher, Kai-Steffen J. %A German, Reinhard %B 31st International Conference on Real-Time Networks and Systems %D 2023 %T On the Validity of Credit-Based Shaper Delay Guarantees in Decentralized Reservation Protocols %X Resource reservation is a fundamental mechanism for ensuring quality of service in time-sensitive networks, which can be decentralized by using reservation protocols. In the Ethernet technology Time-Sensitive Networking, this has been proposed in conjunction with the Credit-Based Shaper. For the reservation, the standards assume a maximum worst-case latency bound at each hop. However, we will show through formal analysis and simulation that these worst-case latency bounds are not safe. To face this, we propose an extension to the current standards to allow the reservation of time-sensitive traffic with reliable latency guarantees. The effectiveness of our approach is demonstrated through simulations of both synthetic and industrial networks. Finally, by providing additional information about neighboring devices, we could further increase the maximum reservable traffic by up to 20% in our test cases.
• Towards Understanding the Signaling Traffic in 5G Core Networks. Raffeck, Simon; Geißler, Stefan; Hoßfeld, Tobias. In KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023. 2023.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2023-8, author = {Raffeck, Simon and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023}, keywords = {can}, month = {06}, title = {Towards Understanding the Signaling Traffic in 5G Core Networks}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-8 %A Raffeck, Simon %A Geißler, Stefan %A Hoßfeld, Tobias %B KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 %D 2023 %T Towards Understanding the Signaling Traffic in 5G Core Networks

• Analytical Model for the Energy Efficiency in Low Power IoT Deployments. Hoßfeld, Tobias; Raffeck, Simon; Loh, Frank; Geißler, Stefan. In 1st International Workshop on Network Energy Efficiency in the Softwarization Era. 2022.
  • [ Abstract ]
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  The recent rise of the Internet of Things (IoT) has given way to numerous challenges and research questions. One of the most critical issues in the area of low powered devices is the question of energy efficiency. Here, technologies like LoRa or Zigbee emerged, promising low power consumption while maintaining adequate performance. However, even when using these tailor made technologies, several configuration aspects need to be taken into account to provide high performance, energy efficient operation. To this end, we propose a generic model to compute the energy efficiency of wireless sensors under the assumption of perfect CSMA/CA channel access. We present numerical results for a typical LoRa device and highlight extensions towards other channel access mechanisms. Finally, we apply Kleinrock's power metric to obtain ideal system configurations for varying load parameters.

  @inproceedings{info3-inproceedings-2022-6, abstract = {The recent rise of the Internet of Things (IoT) has given way to numerous challenges and research questions. One of the most critical issues in the area of low powered devices is the question of energy efficiency. Here, technologies like LoRa or Zigbee emerged, promising low power consumption while maintaining adequate performance. However, even when using these tailor made technologies, several configuration aspects need to be taken into account to provide high performance, energy efficient operation. To this end, we propose a generic model to compute the energy efficiency of wireless sensors under the assumption of perfect CSMA/CA channel access. We present numerical results for a typical LoRa device and highlight extensions towards other channel access mechanisms. Finally, we apply Kleinrock's power metric to obtain ideal system configurations for varying load parameters.}, author = {Hoßfeld, Tobias and Raffeck, Simon and Loh, Frank and Geißler, Stefan}, booktitle = {1st International Workshop on Network Energy Efficiency in the Softwarization Era}, keywords = {can}, month = {06}, title = {Analytical Model for the Energy Efficiency in Low Power IoT Deployments}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-6 %A Hoßfeld, Tobias %A Raffeck, Simon %A Loh, Frank %A Geißler, Stefan %B 1st International Workshop on Network Energy Efficiency in the Softwarization Era %D 2022 %T Analytical Model for the Energy Efficiency in Low Power IoT Deployments %X The recent rise of the Internet of Things (IoT) has given way to numerous challenges and research questions. One of the most critical issues in the area of low powered devices is the question of energy efficiency. Here, technologies like LoRa or Zigbee emerged, promising low power consumption while maintaining adequate performance. However, even when using these tailor made technologies, several configuration aspects need to be taken into account to provide high performance, energy efficient operation. To this end, we propose a generic model to compute the energy efficiency of wireless sensors under the assumption of perfect CSMA/CA channel access. We present numerical results for a typical LoRa device and highlight extensions towards other channel access mechanisms. Finally, we apply Kleinrock's power metric to obtain ideal system configurations for varying load parameters.
• ML-based Performance Prediction of SDN using Simulated Data from Real and Synthetic Networks. Dietz, Katharina; Gray, Nicholas; Seufert, Michael; Hoßfeld, Tobias. In 33th IEEE/IFIP Network Operations and Management Symposium (NOMS). Budapest, Hungary, 2022.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2022-2, address = {Budapest, Hungary}, author = {Dietz, Katharina and Gray, Nicholas and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {33th IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {ucn}, month = {04}, title = {ML-based Performance Prediction of SDN using Simulated Data from Real and Synthetic Networks}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-2 %A Dietz, Katharina %A Gray, Nicholas %A Seufert, Michael %A Hoßfeld, Tobias %B 33th IEEE/IFIP Network Operations and Management Symposium (NOMS) %C Budapest, Hungary %D 2022 %T ML-based Performance Prediction of SDN using Simulated Data from Real and Synthetic Networks
• Simulative Performance Study of Slotted Aloha for LoRaWAN Channel Access. Loh, Frank; Mehling, Noah; Geißler, Stefan; Hoßfeld, Tobias. In IEEE/IFIP Network Operations and Management Symposium. 2022.
  • [ Abstract ]
  • [ BibTeX ]
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  Future Internet of Things deployments generate a multitude of new challenges and opportunities. While 5G networks promise massive throughput rates with ultra low delays, many verticals in the areas of Industry 4.0, Smart City, or Smart Agriculture only transmit tiny amounts of data and instead demand high energy efficiency. This is addressed by access technologies like Low Power Wide Area Networks being com- plementary to high performance 5G networks. Especially Long Range Wide Area Network (LoRaWAN) promises transmissions across long distances with low energy requirements with the drawback of unreliable transmission due to potential message collisions through random channel access. For that reason, a broad parameter study simulation for LoRaWAN channel access with slotted Aloha is presented for real world scenarios and influences like clock drifts or cross traffic. The key impact factors of this channel access approach are studied with focus on the collision probability in various scenarios and simulation results are compared to the current state of the art. The contribution of this work are guidelines for parameter settings in a LoRaWAN with slotted Aloha channel access and performance comparisons for different settings. This information is crucial to scale and operate future LoRaWANs.

  @inproceedings{info3-article-2022-13, abstract = {Future Internet of Things deployments generate a multitude of new challenges and opportunities. While 5G networks promise massive throughput rates with ultra low delays, many verticals in the areas of Industry 4.0, Smart City, or Smart Agriculture only transmit tiny amounts of data and instead demand high energy efficiency. This is addressed by access technologies like Low Power Wide Area Networks being com- plementary to high performance 5G networks. Especially Long Range Wide Area Network (LoRaWAN) promises transmissions across long distances with low energy requirements with the drawback of unreliable transmission due to potential message collisions through random channel access. For that reason, a broad parameter study simulation for LoRaWAN channel access with slotted Aloha is presented for real world scenarios and influences like clock drifts or cross traffic. The key impact factors of this channel access approach are studied with focus on the collision probability in various scenarios and simulation results are compared to the current state of the art. The contribution of this work are guidelines for parameter settings in a LoRaWAN with slotted Aloha channel access and performance comparisons for different settings. This information is crucial to scale and operate future LoRaWANs.}, author = {Loh, Frank and Mehling, Noah and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {IEEE/IFIP Network Operations and Management Symposium}, keywords = {can}, month = {04}, title = {Simulative Performance Study of Slotted Aloha for LoRaWAN Channel Access}, year = 2022 }

  %0 Conference Paper %1 info3-article-2022-13 %A Loh, Frank %A Mehling, Noah %A Geißler, Stefan %A Hoßfeld, Tobias %B IEEE/IFIP Network Operations and Management Symposium %D 2022 %T Simulative Performance Study of Slotted Aloha for LoRaWAN Channel Access %X Future Internet of Things deployments generate a multitude of new challenges and opportunities. While 5G networks promise massive throughput rates with ultra low delays, many verticals in the areas of Industry 4.0, Smart City, or Smart Agriculture only transmit tiny amounts of data and instead demand high energy efficiency. This is addressed by access technologies like Low Power Wide Area Networks being com- plementary to high performance 5G networks. Especially Long Range Wide Area Network (LoRaWAN) promises transmissions across long distances with low energy requirements with the drawback of unreliable transmission due to potential message collisions through random channel access. For that reason, a broad parameter study simulation for LoRaWAN channel access with slotted Aloha is presented for real world scenarios and influences like clock drifts or cross traffic. The key impact factors of this channel access approach are studied with focus on the collision probability in various scenarios and simulation results are compared to the current state of the art. The contribution of this work are guidelines for parameter settings in a LoRaWAN with slotted Aloha channel access and performance comparisons for different settings. This information is crucial to scale and operate future LoRaWANs.
• Data Usage in IoT: A Characterization of GTP Tunnels in M2M Mobile Networks. Raffeck, Simon; Geißler, Stefan; Krolikowski, Michael; Gebert, Steffen; Hoßfeld, Tobias. In 2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA). 2022.
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  IoT and M2M devices have seen a significant growth in usage and deployment over the last years. Gaining insight into device and data usage behavior exhibited by the participants of mobile networks is elementary for MNO and MVNO to scale their networks and provide a reliable service. This work aims to make use of its first of a kind dataset, spanning multiple countries and MNO, to provide a detailed characterization of GTP tunnels and devices. To this end, general statistics are used to describe the observed data traffic focusing on the distribution of the tunnel duration and volume as well as periodic device behavior. An approximate metric is introduced to analyze the periodicity and synchronicity of IoT devices. Lastly, we publish the data investigated in this work and provide a large scale dataset on the data usage behavior of IoT devices to interested researchers.

  @inproceedings{info3-inproceedings-2022-5, abstract = {IoT and M2M devices have seen a significant growth in usage and deployment over the last years. Gaining insight into device and data usage behavior exhibited by the participants of mobile networks is elementary for MNO and MVNO to scale their networks and provide a reliable service. This work aims to make use of its first of a kind dataset, spanning multiple countries and MNO, to provide a detailed characterization of GTP tunnels and devices. To this end, general statistics are used to describe the observed data traffic focusing on the distribution of the tunnel duration and volume as well as periodic device behavior. An approximate metric is introduced to analyze the periodicity and synchronicity of IoT devices. Lastly, we publish the data investigated in this work and provide a large scale dataset on the data usage behavior of IoT devices to interested researchers.}, author = {Raffeck, Simon and Geißler, Stefan and Krolikowski, Michael and Gebert, Steffen and Hoßfeld, Tobias}, booktitle = {2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA)}, keywords = {can}, month = {04}, title = {Data Usage in IoT: A Characterization of GTP Tunnels in M2M Mobile Networks}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-5 %A Raffeck, Simon %A Geißler, Stefan %A Krolikowski, Michael %A Gebert, Steffen %A Hoßfeld, Tobias %B 2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA) %D 2022 %T Data Usage in IoT: A Characterization of GTP Tunnels in M2M Mobile Networks %X IoT and M2M devices have seen a significant growth in usage and deployment over the last years. Gaining insight into device and data usage behavior exhibited by the participants of mobile networks is elementary for MNO and MVNO to scale their networks and provide a reliable service. This work aims to make use of its first of a kind dataset, spanning multiple countries and MNO, to provide a detailed characterization of GTP tunnels and devices. To this end, general statistics are used to describe the observed data traffic focusing on the distribution of the tunnel duration and volume as well as periodic device behavior. An approximate metric is introduced to analyze the periodicity and synchronicity of IoT devices. Lastly, we publish the data investigated in this work and provide a large scale dataset on the data usage behavior of IoT devices to interested researchers.
• On Learning Hierarchical Embeddings from Encrypted Network Traffic. Wehner, Nikolas; Ring, Markus; Schüler, Joshua; Hotho, Andreas; Hoßfeld, Tobias; Seufert, Michael. In 33th IEEE/IFIP Network Operations and Management Symposium (NOMS). Budapest, Hungary, 2022.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  This work presents a novel concept for learning embeddings from encrypted network traffic. In contrast to existing approaches, we evaluate the feasibility of hierarchical embeddings by iteratively aggregating packet embeddings to flow embeddings, and flow embeddings to trace embeddings. The hierarchical embedding concept was designed to especially consider complex dependencies of Internet traffic on different time scales. We describe this novel embedding concept for the domain of network traffic in full detail, and evaluate its performance for the downstream task of website fingerprinting, i.e., identifying websites from encrypted traffic, which is relevant for network management, e.g., as a prerequisite for QoE monitoring or for intrusion detection. Our evaluation reveals that embeddings are a promising solution for website fingerprinting as our model correctly labels up to 99.8\% of traces from 500 target websites.

  @inproceedings{info3-inproceedings-2022-1, abstract = {This work presents a novel concept for learning embeddings from encrypted network traffic. In contrast to existing approaches, we evaluate the feasibility of hierarchical embeddings by iteratively aggregating packet embeddings to flow embeddings, and flow embeddings to trace embeddings. The hierarchical embedding concept was designed to especially consider complex dependencies of Internet traffic on different time scales. We describe this novel embedding concept for the domain of network traffic in full detail, and evaluate its performance for the downstream task of website fingerprinting, i.e., identifying websites from encrypted traffic, which is relevant for network management, e.g., as a prerequisite for QoE monitoring or for intrusion detection. Our evaluation reveals that embeddings are a promising solution for website fingerprinting as our model correctly labels up to 99.8\% of traces from 500 target websites.}, address = {Budapest, Hungary}, author = {Wehner, Nikolas and Ring, Markus and Schüler, Joshua and Hotho, Andreas and Hoßfeld, Tobias and Seufert, Michael}, booktitle = {33th IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {On Learning Hierarchical Embeddings from Encrypted Network Traffic}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-1 %A Wehner, Nikolas %A Ring, Markus %A Schüler, Joshua %A Hotho, Andreas %A Hoßfeld, Tobias %A Seufert, Michael %B 33th IEEE/IFIP Network Operations and Management Symposium (NOMS) %C Budapest, Hungary %D 2022 %T On Learning Hierarchical Embeddings from Encrypted Network Traffic %X This work presents a novel concept for learning embeddings from encrypted network traffic. In contrast to existing approaches, we evaluate the feasibility of hierarchical embeddings by iteratively aggregating packet embeddings to flow embeddings, and flow embeddings to trace embeddings. The hierarchical embedding concept was designed to especially consider complex dependencies of Internet traffic on different time scales. We describe this novel embedding concept for the domain of network traffic in full detail, and evaluate its performance for the downstream task of website fingerprinting, i.e., identifying websites from encrypted traffic, which is relevant for network management, e.g., as a prerequisite for QoE monitoring or for intrusion detection. Our evaluation reveals that embeddings are a promising solution for website fingerprinting as our model correctly labels up to 99.8\% of traces from 500 target websites.
• Characterizing Mobile Signaling Anomalies in the Internet-of-Things. Vomhoff, Viktoria; Geißler, Stefan; Loh, Frank; Bauer, Wolfgang; Hoßfeld, Tobias. In 2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA). 2022.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  The development and adoption speed of new Internet of Things (IoT) devices and applications is constantly increasing. In particular in mobile networks, however, constant connectivity for all newly developed, globally spread, and occasionally geographically mobile devices is challenging. While the main business of current network operators is in particular, not to roam these new device generation between different networks, whereas new so-called Mobile Virtual Network Operators (MVNOs) arise with exactly this business case. They use already available Radio Access Networks and deploy SIM cards that are able to establish data connection everywhere on the basis of international roaming agreements. However, because of the complex interconnection of different systems, additional challenges arise. Outages in one network component might impact the whole system. In this work, we study these signaling anomalies called incidents based on a dataset received from a global MVNO. The goal of this work is to determine traffic characteristics during these incidents towards a better understanding of signaling traffic in IoT networks. Thus, this work can be seen as a fundamental basis to help operators in a characterization, and in particular prediction and avoidance of signaling incidents.

  @inproceedings{info3-inproceedings-2022-4, abstract = {The development and adoption speed of new Internet of Things (IoT) devices and applications is constantly increasing. In particular in mobile networks, however, constant connectivity for all newly developed, globally spread, and occasionally geographically mobile devices is challenging. While the main business of current network operators is in particular, not to roam these new device generation between different networks, whereas new so-called Mobile Virtual Network Operators (MVNOs) arise with exactly this business case. They use already available Radio Access Networks and deploy SIM cards that are able to establish data connection everywhere on the basis of international roaming agreements. However, because of the complex interconnection of different systems, additional challenges arise. Outages in one network component might impact the whole system. In this work, we study these signaling anomalies called incidents based on a dataset received from a global MVNO. The goal of this work is to determine traffic characteristics during these incidents towards a better understanding of signaling traffic in IoT networks. Thus, this work can be seen as a fundamental basis to help operators in a characterization, and in particular prediction and avoidance of signaling incidents.}, author = {Vomhoff, Viktoria and Geißler, Stefan and Loh, Frank and Bauer, Wolfgang and Hoßfeld, Tobias}, booktitle = {2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA)}, keywords = {can}, month = {04}, title = {Characterizing Mobile Signaling Anomalies in the Internet-of-Things}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-4 %A Vomhoff, Viktoria %A Geißler, Stefan %A Loh, Frank %A Bauer, Wolfgang %A Hoßfeld, Tobias %B 2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA) %D 2022 %T Characterizing Mobile Signaling Anomalies in the Internet-of-Things %X The development and adoption speed of new Internet of Things (IoT) devices and applications is constantly increasing. In particular in mobile networks, however, constant connectivity for all newly developed, globally spread, and occasionally geographically mobile devices is challenging. While the main business of current network operators is in particular, not to roam these new device generation between different networks, whereas new so-called Mobile Virtual Network Operators (MVNOs) arise with exactly this business case. They use already available Radio Access Networks and deploy SIM cards that are able to establish data connection everywhere on the basis of international roaming agreements. However, because of the complex interconnection of different systems, additional challenges arise. Outages in one network component might impact the whole system. In this work, we study these signaling anomalies called incidents based on a dataset received from a global MVNO. The goal of this work is to determine traffic characteristics during these incidents towards a better understanding of signaling traffic in IoT networks. Thus, this work can be seen as a fundamental basis to help operators in a characterization, and in particular prediction and avoidance of signaling incidents.
• DeepCrypt - Deep Learning for QoE Monitoring and Fingerprinting of User Actions in Adaptive Video Streaming. Casas, Pedro; Seufert, Michael; Wassermann, Sarah; Gardlo, Bruno; Wehner, Nikolas; Schatz, Raimund. In IEEE Conference on Network Softwarization (IEEE NetSoft 2022). 2022.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  We introduce DeepCrypt, a deep-learning based approach to analyze YouTube video streaming Quality of Experience (QoE) from the Internet Service Provider (ISP) perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived on-line from the encrypted stream of bytes, DeepCrypt can infer six different video QoE indicators capturing the user-perceived performance of the service, including the initial playback delay, the number and frequency of rebuffering events, the video playback quality, the video encoding bitrate, and the number of quality changes. DeepCrypt offers deep visibility into the behavior of the end-user, enabling the fingerprinting and detection of different user actions on the video player, such as video pauses and playback scrubbing (forward, backward, out-of-buffer), offering a complete visibility on the video streaming process from in-network traffic measurements. Extensive evaluations over a large and heterogeneous dataset composed of mobile and fixed-line measurements, using the YouTube HTML5 player, the native YouTube mobile app, as well as a generic HTML5 video player built on top of open source libraries, and considering measurements collected at different ISPs, confirm the out-performance of DeepCrypt over previously used shallow-learning models, as well as the deep-model generalization to different video players and network setups. To the best of our knowledge, this is the first paper tackling such a combined QoE and user-actions approach for video streaming applications, using deep learning models over heterogeneous measurements.

  @inproceedings{info3-inproceedings-2022-9, abstract = {We introduce DeepCrypt, a deep-learning based approach to analyze YouTube video streaming Quality of Experience (QoE) from the Internet Service Provider (ISP) perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived on-line from the encrypted stream of bytes, DeepCrypt can infer six different video QoE indicators capturing the user-perceived performance of the service, including the initial playback delay, the number and frequency of rebuffering events, the video playback quality, the video encoding bitrate, and the number of quality changes. DeepCrypt offers deep visibility into the behavior of the end-user, enabling the fingerprinting and detection of different user actions on the video player, such as video pauses and playback scrubbing (forward, backward, out-of-buffer), offering a complete visibility on the video streaming process from in-network traffic measurements. Extensive evaluations over a large and heterogeneous dataset composed of mobile and fixed-line measurements, using the YouTube HTML5 player, the native YouTube mobile app, as well as a generic HTML5 video player built on top of open source libraries, and considering measurements collected at different ISPs, confirm the out-performance of DeepCrypt over previously used shallow-learning models, as well as the deep-model generalization to different video players and network setups. To the best of our knowledge, this is the first paper tackling such a combined QoE and user-actions approach for video streaming applications, using deep learning models over heterogeneous measurements.}, author = {Casas, Pedro and Seufert, Michael and Wassermann, Sarah and Gardlo, Bruno and Wehner, Nikolas and Schatz, Raimund}, booktitle = {IEEE Conference on Network Softwarization (IEEE NetSoft 2022)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {DeepCrypt - Deep Learning for QoE Monitoring and Fingerprinting of User Actions in Adaptive Video Streaming}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-9 %A Casas, Pedro %A Seufert, Michael %A Wassermann, Sarah %A Gardlo, Bruno %A Wehner, Nikolas %A Schatz, Raimund %B IEEE Conference on Network Softwarization (IEEE NetSoft 2022) %D 2022 %T DeepCrypt - Deep Learning for QoE Monitoring and Fingerprinting of User Actions in Adaptive Video Streaming %X We introduce DeepCrypt, a deep-learning based approach to analyze YouTube video streaming Quality of Experience (QoE) from the Internet Service Provider (ISP) perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived on-line from the encrypted stream of bytes, DeepCrypt can infer six different video QoE indicators capturing the user-perceived performance of the service, including the initial playback delay, the number and frequency of rebuffering events, the video playback quality, the video encoding bitrate, and the number of quality changes. DeepCrypt offers deep visibility into the behavior of the end-user, enabling the fingerprinting and detection of different user actions on the video player, such as video pauses and playback scrubbing (forward, backward, out-of-buffer), offering a complete visibility on the video streaming process from in-network traffic measurements. Extensive evaluations over a large and heterogeneous dataset composed of mobile and fixed-line measurements, using the YouTube HTML5 player, the native YouTube mobile app, as well as a generic HTML5 video player built on top of open source libraries, and considering measurements collected at different ISPs, confirm the out-performance of DeepCrypt over previously used shallow-learning models, as well as the deep-model generalization to different video players and network setups. To the best of our knowledge, this is the first paper tackling such a combined QoE and user-actions approach for video streaming applications, using deep learning models over heterogeneous measurements.
• Constant Delay Switching: Asynchronous Traffic Shaping with Jitter Control. Grigorjew, Alexej; Metzger, Florian; Hoßfeld, Tobias; Specht, Johannes; Götz, Franz-Josef; Chen, Feng; Schmitt, Jürgen. In 2022 IFIP Networking Conference (IFIP Networking). 2022.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Recent developments in the Time Sensitive Networking (TSN) group have put forth a number of mechanisms to improve deterministic latency in layer 2 switches. Their shaping approaches differ with respect to prerequisites, flexibility, maximum latency, and latency variation (jitter). Asynchronous solutions provide flexibility in dynamic scenarios, but Credit-Based Shaping (CBS) and Asynchronous Traffic Shaping (ATS) come with a high latency variance, as the minimum latency is not affected by them. Some applications in industrial and automotive use cases require low jitter while trying to avoid a dependency on time synchronization, and even TSN's redundancy mechanism benefits from a lower latency variance. This work is bridging the gap between low-jitter transmission requirements and asynchronous shaping mechanisms. In this paper, the application of a stateless Asynchronous Constant Delay Shaper (ACDS) is discussed. It collects the queuing duration from the previous bridge to delay each frame for the remaining time such that a constant per-hop delay for each frame is achieved. The discussion includes the prerequisites, the mechanism itself, and its technical complexity, as well as a formal analysis of its guaranteed latency by proving its relation to a token-bucket based ATS. Further, two extensions are discussed, and an evaluation shows the applicability of ACDS by comparing its jitter to ATS in a frame-level simulation.

  @inproceedings{info3-inproceedings-2022-15, abstract = {Recent developments in the Time Sensitive Networking (TSN) group have put forth a number of mechanisms to improve deterministic latency in layer 2 switches. Their shaping approaches differ with respect to prerequisites, flexibility, maximum latency, and latency variation (jitter). Asynchronous solutions provide flexibility in dynamic scenarios, but Credit-Based Shaping (CBS) and Asynchronous Traffic Shaping (ATS) come with a high latency variance, as the minimum latency is not affected by them. Some applications in industrial and automotive use cases require low jitter while trying to avoid a dependency on time synchronization, and even TSN's redundancy mechanism benefits from a lower latency variance. This work is bridging the gap between low-jitter transmission requirements and asynchronous shaping mechanisms. In this paper, the application of a stateless Asynchronous Constant Delay Shaper (ACDS) is discussed. It collects the queuing duration from the previous bridge to delay each frame for the remaining time such that a constant per-hop delay for each frame is achieved. The discussion includes the prerequisites, the mechanism itself, and its technical complexity, as well as a formal analysis of its guaranteed latency by proving its relation to a token-bucket based ATS. Further, two extensions are discussed, and an evaluation shows the applicability of ACDS by comparing its jitter to ATS in a frame-level simulation.}, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes and Götz, Franz-Josef and Chen, Feng and Schmitt, Jürgen}, booktitle = {2022 IFIP Networking Conference (IFIP Networking)}, keywords = {kosinu5}, month = {06}, title = {Constant Delay Switching: Asynchronous Traffic Shaping with Jitter Control}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-15 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %A Götz, Franz-Josef %A Chen, Feng %A Schmitt, Jürgen %B 2022 IFIP Networking Conference (IFIP Networking) %D 2022 %T Constant Delay Switching: Asynchronous Traffic Shaping with Jitter Control %X Recent developments in the Time Sensitive Networking (TSN) group have put forth a number of mechanisms to improve deterministic latency in layer 2 switches. Their shaping approaches differ with respect to prerequisites, flexibility, maximum latency, and latency variation (jitter). Asynchronous solutions provide flexibility in dynamic scenarios, but Credit-Based Shaping (CBS) and Asynchronous Traffic Shaping (ATS) come with a high latency variance, as the minimum latency is not affected by them. Some applications in industrial and automotive use cases require low jitter while trying to avoid a dependency on time synchronization, and even TSN's redundancy mechanism benefits from a lower latency variance. This work is bridging the gap between low-jitter transmission requirements and asynchronous shaping mechanisms. In this paper, the application of a stateless Asynchronous Constant Delay Shaper (ACDS) is discussed. It collects the queuing duration from the previous bridge to delay each frame for the remaining time such that a constant per-hop delay for each frame is achieved. The discussion includes the prerequisites, the mechanism itself, and its technical complexity, as well as a formal analysis of its guaranteed latency by proving its relation to a token-bucket based ATS. Further, two extensions are discussed, and an evaluation shows the applicability of ACDS by comparing its jitter to ATS in a frame-level simulation.
• X-Ray Goggles for the ISP: Improving in-Network Web and App QoE Monitoring with Deep Learning. Casas, Pedro; Wassermann, Sarah; Seufert, Michael; Wehner, Nikolas; Dinica, Olivia; Hoßfeld, Tobias. In Network Traffic Measurement and Analysis Conference (TMA). 2022.
  • [ Abstract ]
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  The wide adoption of end-to-end encryption is drastically limiting the visibility Internet Service Providers (ISPs) have on the performance of the services consumed by their customers. In times of strong competition, where customer experience plays a key role in churn management, ISPs require novel solutions enabling network-wide Quality of Experience (QoE) monitoring. To this end, we present DeepQoE, a deep-learning based approach to infer the QoE of web services and mobile applications from the ISP perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived from the encrypted stream of bytes as input to deep Convolutional Neural Networks (CNNs), DeepQoE infers the Speed Index of web browsing sessions and general mobile apps with unprecedented accuracy, improving the state of the art by more than 25%, and reducing the QoE inference error in terms of mean opinion scores by nearly 40%. DeepQoE implements a web fingerprinting solution to identify individual web browsing sessions within concurrent web pages traffic, enabling highly detailed, per web page QoE inference in practical deployments. Extensive evaluations over a large and heterogeneous dataset composed of web and app measurements, using different device types and for top-popular websites and apps, confirm the out-performance of DeepQoE over previously used shallow-learning models, as well as the deep-model generalization to different devices, web pages, apps, and network setups. DeepQoE is the first deployable system providing such a deep, highly-detailed QoE for individual web browsing and mobile apps over encrypted traffic, using deep learning models on heterogeneous measurements.

  @inproceedings{info3-inproceedings-2022-11, abstract = {The wide adoption of end-to-end encryption is drastically limiting the visibility Internet Service Providers (ISPs) have on the performance of the services consumed by their customers. In times of strong competition, where customer experience plays a key role in churn management, ISPs require novel solutions enabling network-wide Quality of Experience (QoE) monitoring. To this end, we present DeepQoE, a deep-learning based approach to infer the QoE of web services and mobile applications from the ISP perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived from the encrypted stream of bytes as input to deep Convolutional Neural Networks (CNNs), DeepQoE infers the Speed Index of web browsing sessions and general mobile apps with unprecedented accuracy, improving the state of the art by more than 25%, and reducing the QoE inference error in terms of mean opinion scores by nearly 40%. DeepQoE implements a web fingerprinting solution to identify individual web browsing sessions within concurrent web pages traffic, enabling highly detailed, per web page QoE inference in practical deployments. Extensive evaluations over a large and heterogeneous dataset composed of web and app measurements, using different device types and for top-popular websites and apps, confirm the out-performance of DeepQoE over previously used shallow-learning models, as well as the deep-model generalization to different devices, web pages, apps, and network setups. DeepQoE is the first deployable system providing such a deep, highly-detailed QoE for individual web browsing and mobile apps over encrypted traffic, using deep learning models on heterogeneous measurements.}, author = {Casas, Pedro and Wassermann, Sarah and Seufert, Michael and Wehner, Nikolas and Dinica, Olivia and Hoßfeld, Tobias}, booktitle = {Network Traffic Measurement and Analysis Conference (TMA)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {X-Ray Goggles for the ISP: Improving in-Network Web and App QoE Monitoring with Deep Learning}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-11 %A Casas, Pedro %A Wassermann, Sarah %A Seufert, Michael %A Wehner, Nikolas %A Dinica, Olivia %A Hoßfeld, Tobias %B Network Traffic Measurement and Analysis Conference (TMA) %D 2022 %T X-Ray Goggles for the ISP: Improving in-Network Web and App QoE Monitoring with Deep Learning %X The wide adoption of end-to-end encryption is drastically limiting the visibility Internet Service Providers (ISPs) have on the performance of the services consumed by their customers. In times of strong competition, where customer experience plays a key role in churn management, ISPs require novel solutions enabling network-wide Quality of Experience (QoE) monitoring. To this end, we present DeepQoE, a deep-learning based approach to infer the QoE of web services and mobile applications from the ISP perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived from the encrypted stream of bytes as input to deep Convolutional Neural Networks (CNNs), DeepQoE infers the Speed Index of web browsing sessions and general mobile apps with unprecedented accuracy, improving the state of the art by more than 25%, and reducing the QoE inference error in terms of mean opinion scores by nearly 40%. DeepQoE implements a web fingerprinting solution to identify individual web browsing sessions within concurrent web pages traffic, enabling highly detailed, per web page QoE inference in practical deployments. Extensive evaluations over a large and heterogeneous dataset composed of web and app measurements, using different device types and for top-popular websites and apps, confirm the out-performance of DeepQoE over previously used shallow-learning models, as well as the deep-model generalization to different devices, web pages, apps, and network setups. DeepQoE is the first deployable system providing such a deep, highly-detailed QoE for individual web browsing and mobile apps over encrypted traffic, using deep learning models on heterogeneous measurements.
• Graph-Based Gateway Placement for Better Performance in LoRaWAN Deployments. Loh, Frank; Mehling, Noah; Geißler, Stefan; Hoßfeld, Tobias. In 20th Mediterranean Communication and Computer Networking Conference (MedComNet). 2022.
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  Low Power Wide Area Networks with Long Range Wide Area Networks (LoRaWANs) as one of their most prominent representatives are very promising solutions for future Internet of Things deployments. The technology is characterized by low energy requirements leading to long battery lifetimes. However, the drawback is very limited throughput rates. However, the unreliable nature of the LoRa technology is hindering the adoption. Especially its random channel access approach leads to significant message collisions and thus, data loss in larger deployments. From a network planning point of view, one possibility to deal with collisions is the reduction of potentially colliding messages at the frequency bands in combination with limiting the transmission duration of messages. For that reason, we present a novel graph-based gateway placement approach. The main focus is collision probability reduction, which directly increases reliability in LoRaWAN deployments. We show that our approach performs similar to state-of-the-art related work in the worst case and reduces the required number of gateways by up to 40% while reducing the collision probability by up to 70%. Furthermore, we discuss the scalability of our approach to cover arbitrarily large networks with gateways and only little overhead by splitting the problem into smaller sub-problems.

  @inproceedings{info3-inproceedings-2022-19, abstract = {Low Power Wide Area Networks with Long Range Wide Area Networks (LoRaWANs) as one of their most prominent representatives are very promising solutions for future Internet of Things deployments. The technology is characterized by low energy requirements leading to long battery lifetimes. However, the drawback is very limited throughput rates. However, the unreliable nature of the LoRa technology is hindering the adoption. Especially its random channel access approach leads to significant message collisions and thus, data loss in larger deployments. From a network planning point of view, one possibility to deal with collisions is the reduction of potentially colliding messages at the frequency bands in combination with limiting the transmission duration of messages. For that reason, we present a novel graph-based gateway placement approach. The main focus is collision probability reduction, which directly increases reliability in LoRaWAN deployments. We show that our approach performs similar to state-of-the-art related work in the worst case and reduces the required number of gateways by up to 40% while reducing the collision probability by up to 70%. Furthermore, we discuss the scalability of our approach to cover arbitrarily large networks with gateways and only little overhead by splitting the problem into smaller sub-problems.}, author = {Loh, Frank and Mehling, Noah and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {20th Mediterranean Communication and Computer Networking Conference (MedComNet)}, keywords = {5mart}, month = {06}, title = {Graph-Based Gateway Placement for Better Performance in LoRaWAN Deployments}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-19 %A Loh, Frank %A Mehling, Noah %A Geißler, Stefan %A Hoßfeld, Tobias %B 20th Mediterranean Communication and Computer Networking Conference (MedComNet) %D 2022 %T Graph-Based Gateway Placement for Better Performance in LoRaWAN Deployments %X Low Power Wide Area Networks with Long Range Wide Area Networks (LoRaWANs) as one of their most prominent representatives are very promising solutions for future Internet of Things deployments. The technology is characterized by low energy requirements leading to long battery lifetimes. However, the drawback is very limited throughput rates. However, the unreliable nature of the LoRa technology is hindering the adoption. Especially its random channel access approach leads to significant message collisions and thus, data loss in larger deployments. From a network planning point of view, one possibility to deal with collisions is the reduction of potentially colliding messages at the frequency bands in combination with limiting the transmission duration of messages. For that reason, we present a novel graph-based gateway placement approach. The main focus is collision probability reduction, which directly increases reliability in LoRaWAN deployments. We show that our approach performs similar to state-of-the-art related work in the worst case and reduces the required number of gateways by up to 40% while reducing the collision probability by up to 70%. Furthermore, we discuss the scalability of our approach to cover arbitrarily large networks with gateways and only little overhead by splitting the problem into smaller sub-problems.
• Waiting along the Path: How Browsing Delays Impact the QoE of Music Streaming Applications. Seufert, Anika; Schweifler, Ralf; Poignée, Fabian; Seufert, Michael; Hoßfeld, Tobias. In 14th International Conference on Quality of Multimedia Experience (QoMEX). 2022.
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  Streaming has become the dominant source of media consumption, which not only applies to the widely researched field of video streaming, but also to music streaming. Here, previous studies so far have only researched the impact of streaming aspects, such as stalling events or initial loading times, on the QoE of music streaming. However, when using a music streaming application, users are already facing waiting times along the click path before they can start the actual streaming. These waiting times are caused by browsing delays, e.g., during searching for songs or scrolling through playlists, and can potentially deteriorate the QoE of the music streaming application. In this work, we conduct an online QoE study to quantify the impact of these browsing delays with the support of an emulated mobile music streaming web app. We found that browsing delays have no impact on the music streaming QoE, which shows that users are able to clearly distinguish between the two main functionalities of such apps, namely, browsing and streaming. However, browsing delays significantly reduce the QoE of the entire music streaming application, to a similar extent as if QoE degradations happen during the actual streaming. This shows that both browsing and streaming are equally important and have to be considered when designing music streaming applications.

  @inproceedings{info3-inproceedings-2022-13, abstract = {Streaming has become the dominant source of media consumption, which not only applies to the widely researched field of video streaming, but also to music streaming. Here, previous studies so far have only researched the impact of streaming aspects, such as stalling events or initial loading times, on the QoE of music streaming. However, when using a music streaming application, users are already facing waiting times along the click path before they can start the actual streaming. These waiting times are caused by browsing delays, e.g., during searching for songs or scrolling through playlists, and can potentially deteriorate the QoE of the music streaming application. In this work, we conduct an online QoE study to quantify the impact of these browsing delays with the support of an emulated mobile music streaming web app. We found that browsing delays have no impact on the music streaming QoE, which shows that users are able to clearly distinguish between the two main functionalities of such apps, namely, browsing and streaming. However, browsing delays significantly reduce the QoE of the entire music streaming application, to a similar extent as if QoE degradations happen during the actual streaming. This shows that both browsing and streaming are equally important and have to be considered when designing music streaming applications.}, author = {Seufert, Anika and Schweifler, Ralf and Poignée, Fabian and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {14th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Waiting along the Path: How Browsing Delays Impact the QoE of Music Streaming Applications}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-13 %A Seufert, Anika %A Schweifler, Ralf %A Poignée, Fabian %A Seufert, Michael %A Hoßfeld, Tobias %B 14th International Conference on Quality of Multimedia Experience (QoMEX) %D 2022 %T Waiting along the Path: How Browsing Delays Impact the QoE of Music Streaming Applications %X Streaming has become the dominant source of media consumption, which not only applies to the widely researched field of video streaming, but also to music streaming. Here, previous studies so far have only researched the impact of streaming aspects, such as stalling events or initial loading times, on the QoE of music streaming. However, when using a music streaming application, users are already facing waiting times along the click path before they can start the actual streaming. These waiting times are caused by browsing delays, e.g., during searching for songs or scrolling through playlists, and can potentially deteriorate the QoE of the music streaming application. In this work, we conduct an online QoE study to quantify the impact of these browsing delays with the support of an emulated mobile music streaming web app. We found that browsing delays have no impact on the music streaming QoE, which shows that users are able to clearly distinguish between the two main functionalities of such apps, namely, browsing and streaming. However, browsing delays significantly reduce the QoE of the entire music streaming application, to a similar extent as if QoE degradations happen during the actual streaming. This shows that both browsing and streaming are equally important and have to be considered when designing music streaming applications.
• DBM: Decentralized Burst Mitigation for Self-Organizing LoRa Deployments. Raffeck, Simon; Geißler, Stefan; Hoßfeld, Tobias. In KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2022. 2022.
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  @inproceedings{info3-inproceedings-2022-7, author = {Raffeck, Simon and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2022}, keywords = {can}, month = {07}, title = {DBM: Decentralized Burst Mitigation for Self-Organizing LoRa Deployments}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-7 %A Raffeck, Simon %A Geißler, Stefan %A Hoßfeld, Tobias %B KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2022 %D 2022 %T DBM: Decentralized Burst Mitigation for Self-Organizing LoRa Deployments
• Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation. Geißler, Stefan; Lange, Stanislav; Haßllinger, Gerhard; Tran-Gia, Phuoc; Hoßfeld, Tobias. In 34st International Teletraffic Congress (ITC). , Shenzhen, China. 2022.
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  The analytical and numerical performance evaluation of network components and distributed systems has been a staple in the networking community for many years. However, the ever growing complexity of modern systems and the need to gain detailed insights into systems consisting of many, interconnected components emphasizes the need for an extension to the classical single-component approach, and although approaches like Jackson Networks exist, their limited application scope lags behind the complexity of modern environments. To this end, we revisit existing models of the common Gi/Gi/1-oo queue, extend them to allow the concatenation of multiple queueing components, and evaluate the approximation error introduced through renewal approximation. We revisit previously performed parameter studies and evaluate the approximation error for a wide range of parameter combinations that we can solve through the power of modern computing equipment and efficient numerical implementations of our models. We show the main impact factors for the linear concatenation of queueing components as well as the split and superposition of processes. Our evaluations show that the renewal approximation can be applied to a wide range of parameters while still obtaining results within acceptable error margins.

  @inproceedings{info3-inproceedings-2022-17, abstract = {The analytical and numerical performance evaluation of network components and distributed systems has been a staple in the networking community for many years. However, the ever growing complexity of modern systems and the need to gain detailed insights into systems consisting of many, interconnected components emphasizes the need for an extension to the classical single-component approach, and although approaches like Jackson Networks exist, their limited application scope lags behind the complexity of modern environments. To this end, we revisit existing models of the common Gi/Gi/1-oo queue, extend them to allow the concatenation of multiple queueing components, and evaluate the approximation error introduced through renewal approximation. We revisit previously performed parameter studies and evaluate the approximation error for a wide range of parameter combinations that we can solve through the power of modern computing equipment and efficient numerical implementations of our models. We show the main impact factors for the linear concatenation of queueing components as well as the split and superposition of processes. Our evaluations show that the renewal approximation can be applied to a wide range of parameters while still obtaining results within acceptable error margins.}, author = {Geißler, Stefan and Lange, Stanislav and Haßllinger, Gerhard and Tran-Gia, Phuoc and Hoßfeld, Tobias}, booktitle = {34st International Teletraffic Congress (ITC). , Shenzhen, China}, keywords = {can}, month = {09}, title = {Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-17 %A Geißler, Stefan %A Lange, Stanislav %A Haßllinger, Gerhard %A Tran-Gia, Phuoc %A Hoßfeld, Tobias %B 34st International Teletraffic Congress (ITC). , Shenzhen, China %D 2022 %T Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation %X The analytical and numerical performance evaluation of network components and distributed systems has been a staple in the networking community for many years. However, the ever growing complexity of modern systems and the need to gain detailed insights into systems consisting of many, interconnected components emphasizes the need for an extension to the classical single-component approach, and although approaches like Jackson Networks exist, their limited application scope lags behind the complexity of modern environments. To this end, we revisit existing models of the common Gi/Gi/1-oo queue, extend them to allow the concatenation of multiple queueing components, and evaluate the approximation error introduced through renewal approximation. We revisit previously performed parameter studies and evaluate the approximation error for a wide range of parameter combinations that we can solve through the power of modern computing equipment and efficient numerical implementations of our models. We show the main impact factors for the linear concatenation of queueing components as well as the split and superposition of processes. Our evaluations show that the renewal approximation can be applied to a wide range of parameters while still obtaining results within acceptable error margins.
• Fingerprinting Webpages and Smartphone Apps from Encrypted Network Traffic with WebScanner. Casas, Pedro; Wehner, Nikolas; Wassermann, Sarah; Seufert, Michael. In Global Internet (GI) Symposium. Paris, France, 2022.
  • [ Abstract ]
  • [ BibTeX ]
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  The wide adoption of end-to-end encryption drastically limits the visibility Internet Service Providers (ISPs) have on the services consumed by their customers. This is particularly challenging for monitoring and analysis of web and apps traffic, which is highly complex and heterogeneous. Loading a web page or app today requires tens of flows to download the various resources located in distributed cloud servers from different content providers. We introduce WebScanner, a webpage and app fingerprinting approach capable to identify all the traffic flows corresponding to individual webpage and app loading sessions within concurrent web pages traffic, enabling highly detailed, per webpage analysis in practical deployments. Different from the state of the art in web and app traffic fingerprinting, and as our most relevant contribution, WebScanner automatically performs the parsing of all the traffic generated by a web visit and its isolation from concurrent traffic, instead of assuming that an external oracle system does so. WebScanner also implements a deep fingerprinting approach to detect user action-dependent traffic from apps, relying on simple machine learning models and strong input features as fingerprints. Extensive evaluation across a large measurement dataset of popular webpages and mobile apps confirms the outstanding performance of WebScanner, identifying the top-500 Alexa websites with precision and recall (P/R) above 95%, isolating their full contents with P/R above 80% for up to 15 concurrent webpages, and detecting specific action-dependent apps traffic with average P/R above 92%.

  @inproceedings{info3-inproceedings-2022-18, abstract = {The wide adoption of end-to-end encryption drastically limits the visibility Internet Service Providers (ISPs) have on the services consumed by their customers. This is particularly challenging for monitoring and analysis of web and apps traffic, which is highly complex and heterogeneous. Loading a web page or app today requires tens of flows to download the various resources located in distributed cloud servers from different content providers. We introduce WebScanner, a webpage and app fingerprinting approach capable to identify all the traffic flows corresponding to individual webpage and app loading sessions within concurrent web pages traffic, enabling highly detailed, per webpage analysis in practical deployments. Different from the state of the art in web and app traffic fingerprinting, and as our most relevant contribution, WebScanner automatically performs the parsing of all the traffic generated by a web visit and its isolation from concurrent traffic, instead of assuming that an external oracle system does so. WebScanner also implements a deep fingerprinting approach to detect user action-dependent traffic from apps, relying on simple machine learning models and strong input features as fingerprints. Extensive evaluation across a large measurement dataset of popular webpages and mobile apps confirms the outstanding performance of WebScanner, identifying the top-500 Alexa websites with precision and recall (P/R) above 95%, isolating their full contents with P/R above 80% for up to 15 concurrent webpages, and detecting specific action-dependent apps traffic with average P/R above 92%.}, address = {Paris, France}, author = {Casas, Pedro and Wehner, Nikolas and Wassermann, Sarah and Seufert, Michael}, booktitle = {Global Internet (GI) Symposium}, keywords = {ucn}, month = 11, title = {Fingerprinting Webpages and Smartphone Apps from Encrypted Network Traffic with WebScanner}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-18 %A Casas, Pedro %A Wehner, Nikolas %A Wassermann, Sarah %A Seufert, Michael %B Global Internet (GI) Symposium %C Paris, France %D 2022 %T Fingerprinting Webpages and Smartphone Apps from Encrypted Network Traffic with WebScanner %X The wide adoption of end-to-end encryption drastically limits the visibility Internet Service Providers (ISPs) have on the services consumed by their customers. This is particularly challenging for monitoring and analysis of web and apps traffic, which is highly complex and heterogeneous. Loading a web page or app today requires tens of flows to download the various resources located in distributed cloud servers from different content providers. We introduce WebScanner, a webpage and app fingerprinting approach capable to identify all the traffic flows corresponding to individual webpage and app loading sessions within concurrent web pages traffic, enabling highly detailed, per webpage analysis in practical deployments. Different from the state of the art in web and app traffic fingerprinting, and as our most relevant contribution, WebScanner automatically performs the parsing of all the traffic generated by a web visit and its isolation from concurrent traffic, instead of assuming that an external oracle system does so. WebScanner also implements a deep fingerprinting approach to detect user action-dependent traffic from apps, relying on simple machine learning models and strong input features as fingerprints. Extensive evaluation across a large measurement dataset of popular webpages and mobile apps confirms the outstanding performance of WebScanner, identifying the top-500 Alexa websites with precision and recall (P/R) above 95%, isolating their full contents with P/R above 80% for up to 15 concurrent webpages, and detecting specific action-dependent apps traffic with average P/R above 92%.
• Affordable Measurement Setups for Networking Device Latency with Sub-Microsecond Accuracy. Grigorjew, Alexej; Diederich, Philip; Hoßfeld, Tobias; Kellerer, Wolfgang. In WueWoWAS’22 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks. 2022.
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  This document presents a networking latency measurement setup that focuses on affordability and universal applicability, and can provide sub-microsecond accuracy. It explains the prerequisites, hardware choices, and considerations to respect during measurement. In addition, it discusses the necessity for exhaustive latency measurements when dealing with high availability and low latency requirements. Preliminary results show that the accuracy is within 0.02 microseconds when used with the Intel I350-T2 network adapter.

  @inproceedings{info3-inproceedings-2022-14, abstract = {This document presents a networking latency measurement setup that focuses on affordability and universal applicability, and can provide sub-microsecond accuracy. It explains the prerequisites, hardware choices, and considerations to respect during measurement. In addition, it discusses the necessity for exhaustive latency measurements when dealing with high availability and low latency requirements. Preliminary results show that the accuracy is within 0.02 microseconds when used with the Intel I350-T2 network adapter.}, author = {Grigorjew, Alexej and Diederich, Philip and Hoßfeld, Tobias and Kellerer, Wolfgang}, booktitle = {WueWoWAS'22 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks}, keywords = {appaware2}, month = {07}, title = {Affordable Measurement Setups for Networking Device Latency with Sub-Microsecond Accuracy}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-14 %A Grigorjew, Alexej %A Diederich, Philip %A Hoßfeld, Tobias %A Kellerer, Wolfgang %B WueWoWAS'22 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks %D 2022 %T Affordable Measurement Setups for Networking Device Latency with Sub-Microsecond Accuracy %X This document presents a networking latency measurement setup that focuses on affordability and universal applicability, and can provide sub-microsecond accuracy. It explains the prerequisites, hardware choices, and considerations to respect during measurement. In addition, it discusses the necessity for exhaustive latency measurements when dealing with high availability and low latency requirements. Preliminary results show that the accuracy is within 0.02 microseconds when used with the Intel I350-T2 network adapter.
• Generic Model to Quantify Energy Consumption for Different LoRaWAN Channel Access Methods. Loh, Frank; Raffeck, Simon; Geißler, Stefan; Hoßfeld, Tobias. In 18th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob). 2022.
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  LoRaWAN is one of the most promising Internet of Things technologies with regard to low energy consumption. However, the currently used random channel access has much potential for improvement. Thus, current literature studies alternative channel access approaches, but the energy consumption is often not taken into consideration. For that reason, we present a generic model to quantify energy consumption in LoRaWAN for different channel access mechanisms based on a state machine. With our model, we can describe the energy consumption for specific access mechanisms or for the complete network. Our model shows that random access only performs best if no additional receive windows are opened. A simple improvement is Listen before Talk. For networks with high load, improvements are achieved by a more complex scheduled MAC. Our model serves as a basis for future energy consumption studies, conducted through measurements or simulations.

  @inproceedings{info3-inproceedings-2022-21, abstract = {LoRaWAN is one of the most promising Internet of Things technologies with regard to low energy consumption. However, the currently used random channel access has much potential for improvement. Thus, current literature studies alternative channel access approaches, but the energy consumption is often not taken into consideration. For that reason, we present a generic model to quantify energy consumption in LoRaWAN for different channel access mechanisms based on a state machine. With our model, we can describe the energy consumption for specific access mechanisms or for the complete network. Our model shows that random access only performs best if no additional receive windows are opened. A simple improvement is Listen before Talk. For networks with high load, improvements are achieved by a more complex scheduled MAC. Our model serves as a basis for future energy consumption studies, conducted through measurements or simulations.}, author = {Loh, Frank and Raffeck, Simon and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {18th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob)}, keywords = {5mart}, month = 10, title = {Generic Model to Quantify Energy Consumption for Different LoRaWAN Channel Access Methods}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-21 %A Loh, Frank %A Raffeck, Simon %A Geißler, Stefan %A Hoßfeld, Tobias %B 18th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob) %D 2022 %T Generic Model to Quantify Energy Consumption for Different LoRaWAN Channel Access Methods %X LoRaWAN is one of the most promising Internet of Things technologies with regard to low energy consumption. However, the currently used random channel access has much potential for improvement. Thus, current literature studies alternative channel access approaches, but the energy consumption is often not taken into consideration. For that reason, we present a generic model to quantify energy consumption in LoRaWAN for different channel access mechanisms based on a state machine. With our model, we can describe the energy consumption for specific access mechanisms or for the complete network. Our model shows that random access only performs best if no additional receive windows are opened. A simple improvement is Listen before Talk. For networks with high load, improvements are achieved by a more complex scheduled MAC. Our model serves as a basis for future energy consumption studies, conducted through measurements or simulations.
• Comparing Traditional and GAN-based Approaches for the Synthesis of Wide Area Network Topologies. Dietz, Katharina; Seufert, Michael; Hoßfeld, Tobias. In 18th International Conference on Network and Service Management (CNSM). Thessaloniki, Greece, 2022.
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  @inproceedings{info3-inproceedings-2022-16, address = {Thessaloniki, Greece}, author = {Dietz, Katharina and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {18th International Conference on Network and Service Management (CNSM)}, keywords = {ucn}, month = 10, title = {Comparing Traditional and GAN-based Approaches for the Synthesis of Wide Area Network Topologies}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-16 %A Dietz, Katharina %A Seufert, Michael %A Hoßfeld, Tobias %B 18th International Conference on Network and Service Management (CNSM) %C Thessaloniki, Greece %D 2022 %T Comparing Traditional and GAN-based Approaches for the Synthesis of Wide Area Network Topologies
• A Vital Improvement? Relating Google’s Core Web Vitals to Actual Web QoE. Wehner, Nikolas; Amir, Monisha; Seufert, Michael; Schatz, Raimund; Hoßfeld, Tobias. In 14th International Conference on Quality of Multimedia Experience (QoMEX), Best Paper Award. Lippstadt, Germany, 2022.
  • [ Abstract ]
  • [ BibTeX ]
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  Providing sophisticated Web Quality of Experience (QoE) has become paramount for web service providers and network operators alike. Due to advances in Web technologies (HTML5, responsive design, etc.), traditional Web QoE models focusing mainly on loading times have to be refined and improved. In this work, we relate Google's Core Web Vitals, a set of metrics for improving user experience, to the loading time aspects of Web QoE. To this end, we first perform objective measurements in the Web using Google's Lighthouse. To close the gap between metrics and experience, we complement these objective measurements with subjective assessment by performing multiple crowdsourcing QoE studies. In these studies, we use CWeQS, a customized framework to emulate the entire web page loading process, and ask users for their experience while controlling the Core Web Vitals. Our results suggest that the Core Web Vitals have less predictive value for Web QoE than expected and that page loading times remain the main influence factor in this context.

  @inproceedings{info3-inproceedings-2022-12, abstract = {Providing sophisticated Web Quality of Experience (QoE) has become paramount for web service providers and network operators alike. Due to advances in Web technologies (HTML5, responsive design, etc.), traditional Web QoE models focusing mainly on loading times have to be refined and improved. In this work, we relate Google's Core Web Vitals, a set of metrics for improving user experience, to the loading time aspects of Web QoE. To this end, we first perform objective measurements in the Web using Google's Lighthouse. To close the gap between metrics and experience, we complement these objective measurements with subjective assessment by performing multiple crowdsourcing QoE studies. In these studies, we use CWeQS, a customized framework to emulate the entire web page loading process, and ask users for their experience while controlling the Core Web Vitals. Our results suggest that the Core Web Vitals have less predictive value for Web QoE than expected and that page loading times remain the main influence factor in this context.}, address = {Lippstadt, Germany}, author = {Wehner, Nikolas and Amir, Monisha and Seufert, Michael and Schatz, Raimund and Hoßfeld, Tobias}, booktitle = {14th International Conference on Quality of Multimedia Experience (QoMEX), Best Paper Award}, keywords = {ucn}, month = {09}, title = {A Vital Improvement? Relating Google's Core Web Vitals to Actual Web QoE}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-12 %A Wehner, Nikolas %A Amir, Monisha %A Seufert, Michael %A Schatz, Raimund %A Hoßfeld, Tobias %B 14th International Conference on Quality of Multimedia Experience (QoMEX), Best Paper Award %C Lippstadt, Germany %D 2022 %T A Vital Improvement? Relating Google's Core Web Vitals to Actual Web QoE %X Providing sophisticated Web Quality of Experience (QoE) has become paramount for web service providers and network operators alike. Due to advances in Web technologies (HTML5, responsive design, etc.), traditional Web QoE models focusing mainly on loading times have to be refined and improved. In this work, we relate Google's Core Web Vitals, a set of metrics for improving user experience, to the loading time aspects of Web QoE. To this end, we first perform objective measurements in the Web using Google's Lighthouse. To close the gap between metrics and experience, we complement these objective measurements with subjective assessment by performing multiple crowdsourcing QoE studies. In these studies, we use CWeQS, a customized framework to emulate the entire web page loading process, and ask users for their experience while controlling the Core Web Vitals. Our results suggest that the Core Web Vitals have less predictive value for Web QoE than expected and that page loading times remain the main influence factor in this context.
• Identification of Signaling Patterns in Mobile IoT Signaling Traffic. Vomhoff, Viktoria; Geißler, Stefan; Hoßfeld, Tobias. In WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks. 2022.
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  @inproceedings{info3-inproceedings-2022-8, author = {Vomhoff, Viktoria and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks}, keywords = {can}, month = {07}, title = {Identification of Signaling Patterns in Mobile IoT Signaling Traffic}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-8 %A Vomhoff, Viktoria %A Geißler, Stefan %A Hoßfeld, Tobias %B WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks %D 2022 %T Identification of Signaling Patterns in Mobile IoT Signaling Traffic
• LoRaWAN Network Planning in Smart Environments: Towards Reliability, Scalability, and Cost Reduction. Loh, Frank; Geißler, Stefan; Hoßfeld, Tobias. In WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks. 2022.
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  The goal in this work is to present a guidance for LoRaWAN planning to improve overall reliability for message transmissions and scalability. At the end, the cost component is discussed. Therefore, a five step approach is presented that helps to plan a LoRaWAN deployment step by step: Based on the device locations, an initial gateway placement is suggested followed by in-depth frequency and channel access planning. After an initial planning phase, updates for channel access and the initial gateway planning is suggested that should also be done periodically during network operation. Since current gateway placement approaches are only studied with random channel access, there is a lot of potential in the cell planning phase. Furthermore, the performance of different channel access approaches is highly related on network load, and thus cell size and sensor density. Last, the influence of different cell planning ideas on expected costs are discussed.

  @inproceedings{info3-inproceedings-2022-20, abstract = {The goal in this work is to present a guidance for LoRaWAN planning to improve overall reliability for message transmissions and scalability. At the end, the cost component is discussed. Therefore, a five step approach is presented that helps to plan a LoRaWAN deployment step by step: Based on the device locations, an initial gateway placement is suggested followed by in-depth frequency and channel access planning. After an initial planning phase, updates for channel access and the initial gateway planning is suggested that should also be done periodically during network operation. Since current gateway placement approaches are only studied with random channel access, there is a lot of potential in the cell planning phase. Furthermore, the performance of different channel access approaches is highly related on network load, and thus cell size and sensor density. Last, the influence of different cell planning ideas on expected costs are discussed.}, author = {Loh, Frank and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks}, keywords = {5mart}, month = {07}, title = {LoRaWAN Network Planning in Smart Environments: Towards Reliability, Scalability, and Cost Reduction}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-20 %A Loh, Frank %A Geißler, Stefan %A Hoßfeld, Tobias %B WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks %D 2022 %T LoRaWAN Network Planning in Smart Environments: Towards Reliability, Scalability, and Cost Reduction %X The goal in this work is to present a guidance for LoRaWAN planning to improve overall reliability for message transmissions and scalability. At the end, the cost component is discussed. Therefore, a five step approach is presented that helps to plan a LoRaWAN deployment step by step: Based on the device locations, an initial gateway placement is suggested followed by in-depth frequency and channel access planning. After an initial planning phase, updates for channel access and the initial gateway planning is suggested that should also be done periodically during network operation. Since current gateway placement approaches are only studied with random channel access, there is a lot of potential in the cell planning phase. Furthermore, the performance of different channel access approaches is highly related on network load, and thus cell size and sensor density. Last, the influence of different cell planning ideas on expected costs are discussed.
• Not all Web Pages are Born the Same. Content Tailored Learning for Web QoE Inference. Casas, Pedro; Wassermann, Sarah; Wehner, Nikolas; Seufert, Michael; Hoßfeld, Tobias. In IEEE International Symposium on Measurements & Networking (M&N 2022). 2022.
  • [ Abstract ]
  • [ BibTeX ]
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  Web Quality of Experience (QoE) monitoring is a critical task for Internet Service Providers (ISPs), especially due to the key role played by customer experience in churn management. Previously, we have tackled the problem of Web QoE inference from the ISP perspective, relying on passive measurement of encrypted network traffic and machine learning models. In this paper, we exploit the broad heterogeneity of contents embedded in web pages to improve the state of the art performance in Web QoE inference, relying on web-content learning model tailoring. By analyzing the top-500 most popular web pages of the Internet through unsupervised learning, we discover different web page content classes which realize significantly different Web QoE inference performance. We train supervised learning inference models separately for each of these classes, using the well-known Speed Index (SI) metric as proxy to Web QoE. Empirical evaluations on a large corpus of Web QoE measurements for top popular websites demonstrate that our combined content-tailored approach improves the inference performance of the SI by almost 30% with respect to previous single-model approaches, reducing the QoE inference error in terms of mean opinion scores by more than 40%.

  @inproceedings{info3-inproceedings-2022-10, abstract = {Web Quality of Experience (QoE) monitoring is a critical task for Internet Service Providers (ISPs), especially due to the key role played by customer experience in churn management. Previously, we have tackled the problem of Web QoE inference from the ISP perspective, relying on passive measurement of encrypted network traffic and machine learning models. In this paper, we exploit the broad heterogeneity of contents embedded in web pages to improve the state of the art performance in Web QoE inference, relying on web-content learning model tailoring. By analyzing the top-500 most popular web pages of the Internet through unsupervised learning, we discover different web page content classes which realize significantly different Web QoE inference performance. We train supervised learning inference models separately for each of these classes, using the well-known Speed Index (SI) metric as proxy to Web QoE. Empirical evaluations on a large corpus of Web QoE measurements for top popular websites demonstrate that our combined content-tailored approach improves the inference performance of the SI by almost 30% with respect to previous single-model approaches, reducing the QoE inference error in terms of mean opinion scores by more than 40%.}, author = {Casas, Pedro and Wassermann, Sarah and Wehner, Nikolas and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {IEEE International Symposium on Measurements & Networking (M&N 2022)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Not all Web Pages are Born the Same. Content Tailored Learning for Web QoE Inference}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-10 %A Casas, Pedro %A Wassermann, Sarah %A Wehner, Nikolas %A Seufert, Michael %A Hoßfeld, Tobias %B IEEE International Symposium on Measurements & Networking (M&N 2022) %D 2022 %T Not all Web Pages are Born the Same. Content Tailored Learning for Web QoE Inference %X Web Quality of Experience (QoE) monitoring is a critical task for Internet Service Providers (ISPs), especially due to the key role played by customer experience in churn management. Previously, we have tackled the problem of Web QoE inference from the ISP perspective, relying on passive measurement of encrypted network traffic and machine learning models. In this paper, we exploit the broad heterogeneity of contents embedded in web pages to improve the state of the art performance in Web QoE inference, relying on web-content learning model tailoring. By analyzing the top-500 most popular web pages of the Internet through unsupervised learning, we discover different web page content classes which realize significantly different Web QoE inference performance. We train supervised learning inference models separately for each of these classes, using the well-known Speed Index (SI) metric as proxy to Web QoE. Empirical evaluations on a large corpus of Web QoE measurements for top popular websites demonstrate that our combined content-tailored approach improves the inference performance of the SI by almost 30% with respect to previous single-model approaches, reducing the QoE inference error in terms of mean opinion scores by more than 40%.

• Distributed Implementation of Deterministic Networking in Existing Non-TSN Ethernet Switches. Grigorjew, Alexej; Baier, Christian; Metzger, Florian; Hoßfeld, Tobias. In Workshop on Time-sensitive and Deterministic Networking (TsDN). 2021.
  • [ Abstract ]
  • [ BibTeX ]
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  Deterministic networking is quickly gaining importance, as several domains previously dominated by bus systems are now switching to Ethernet. While standardization efforts, especially from the Time-Sensitive Networking (TSN) group, are ongoing, practical deployments are still far off until configuration guidelines and resource management are able to use these tools to their full potential. As an alternative, this work presents a working implementation of bounded latency with an off-the-shelf non-TSN Ethernet switch. The solution is based on a distributed reservation protocol and admission control. It proves that bounded latency is already possible with simple priority-based transmission, and it provides valuable insights for the development and operation of future real-time networking solutions.

  @inproceedings{info3-inproceedings-2021-6, abstract = {Deterministic networking is quickly gaining importance, as several domains previously dominated by bus systems are now switching to Ethernet. While standardization efforts, especially from the Time-Sensitive Networking (TSN) group, are ongoing, practical deployments are still far off until configuration guidelines and resource management are able to use these tools to their full potential. As an alternative, this work presents a working implementation of bounded latency with an off-the-shelf non-TSN Ethernet switch. The solution is based on a distributed reservation protocol and admission control. It proves that bounded latency is already possible with simple priority-based transmission, and it provides valuable insights for the development and operation of future real-time networking solutions.}, author = {Grigorjew, Alexej and Baier, Christian and Metzger, Florian and Hoßfeld, Tobias}, booktitle = {Workshop on Time-sensitive and Deterministic Networking (TsDN)}, keywords = {ats-performance}, month = {06}, title = {Distributed Implementation of Deterministic Networking in Existing Non-TSN Ethernet Switches}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-6 %A Grigorjew, Alexej %A Baier, Christian %A Metzger, Florian %A Hoßfeld, Tobias %B Workshop on Time-sensitive and Deterministic Networking (TsDN) %D 2021 %T Distributed Implementation of Deterministic Networking in Existing Non-TSN Ethernet Switches %X Deterministic networking is quickly gaining importance, as several domains previously dominated by bus systems are now switching to Ethernet. While standardization efforts, especially from the Time-Sensitive Networking (TSN) group, are ongoing, practical deployments are still far off until configuration guidelines and resource management are able to use these tools to their full potential. As an alternative, this work presents a working implementation of bounded latency with an off-the-shelf non-TSN Ethernet switch. The solution is based on a distributed reservation protocol and admission control. It proves that bounded latency is already possible with simple priority-based transmission, and it provides valuable insights for the development and operation of future real-time networking solutions.
• Talk to Me: Investigating the Traffic Characteristics of Amazon Echo Dot and Google Home. Loh, Frank; Geissler, Stefan; Schaible, Fabian; Hoßfeld, Tobias. In International Conference on Communications and Electronics, ICCE. 2021.
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  The application area of smart speakers is steadily increasing with the Amazon Echo family and Google Home being brand leaders. Use cases include, among others, updating the calendar, home automation, or simply assisting users in their every day life. With the increasing amount of devices, the traffic generation and requesting process becomes a relevant subject to be studied in order to create traffic models and predict the impact on networks by these types of devices. Furthermore, with a detailed understanding of the devices, service quality can be monitored and improved for the end user. For that reason, in this work the requesting and traffic generation process of the Amazon Echo Dot and Google Home are studied and the generated network load of both devices is compared. With the insights of this study and additional device usage statistics, detailed traffic and usage models can be created.

  @inproceedings{info3-inproceedings-2021-5, abstract = {The application area of smart speakers is steadily increasing with the Amazon Echo family and Google Home being brand leaders. Use cases include, among others, updating the calendar, home automation, or simply assisting users in their every day life. With the increasing amount of devices, the traffic generation and requesting process becomes a relevant subject to be studied in order to create traffic models and predict the impact on networks by these types of devices. Furthermore, with a detailed understanding of the devices, service quality can be monitored and improved for the end user. For that reason, in this work the requesting and traffic generation process of the Amazon Echo Dot and Google Home are studied and the generated network load of both devices is compared. With the insights of this study and additional device usage statistics, detailed traffic and usage models can be created.}, author = {Loh, Frank and Geissler, Stefan and Schaible, Fabian and Hoßfeld, Tobias}, booktitle = {International Conference on Communications and Electronics, ICCE}, keywords = {sys:hidden:inproceedings}, month = {01}, title = {Talk to Me: Investigating the Traffic Characteristics of Amazon Echo Dot and Google Home}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-5 %A Loh, Frank %A Geissler, Stefan %A Schaible, Fabian %A Hoßfeld, Tobias %B International Conference on Communications and Electronics, ICCE %D 2021 %T Talk to Me: Investigating the Traffic Characteristics of Amazon Echo Dot and Google Home %X The application area of smart speakers is steadily increasing with the Amazon Echo family and Google Home being brand leaders. Use cases include, among others, updating the calendar, home automation, or simply assisting users in their every day life. With the increasing amount of devices, the traffic generation and requesting process becomes a relevant subject to be studied in order to create traffic models and predict the impact on networks by these types of devices. Furthermore, with a detailed understanding of the devices, service quality can be monitored and improved for the end user. For that reason, in this work the requesting and traffic generation process of the Amazon Echo Dot and Google Home are studied and the generated network load of both devices is compared. With the insights of this study and additional device usage statistics, detailed traffic and usage models can be created.
• Signaling Traffic in Internet-of-Things Mobile Networks. Geissler, Stefan; Wamser, Florian; Bauer, Wolfang; Krolikowski, Michael; Gebert, Steffen; Hoßfeld, Tobias. In IFIP/IEEE International Symposium on Integrated Network Management (IM 2021). Bordeaux, France (Virtual Conference), 2021.
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  The Internet of Things (IoT) is expected to play an increasingly important role in next-generation mobile networks. Detailed knowledge of this type of traffic and the associated signaling in those networks is of interest to operators and standardization in order to run these networks successfully. The aim of this study is to characterize IoT signaling traffic for mobile communication networks (i) from a network operator’s point of view, (ii) at device level, and (iii) for the establishment of data connections. General statistics on signaling and device behavior, such as the observed IoT traffic volume and message composition, are given before device classes with statistically different signaling behavior are identified. Finally, by characterizing the aggre- gated signaling traffic, we show that the Markov assumption, widespread in standardization and literature, regarding the aggregated arrival process for data connections does not apply in reality.

  @inproceedings{info3-inproceedings-2021-1, abstract = {The Internet of Things (IoT) is expected to play an increasingly important role in next-generation mobile networks. Detailed knowledge of this type of traffic and the associated signaling in those networks is of interest to operators and standardization in order to run these networks successfully. The aim of this study is to characterize IoT signaling traffic for mobile communication networks (i) from a network operator’s point of view, (ii) at device level, and (iii) for the establishment of data connections. General statistics on signaling and device behavior, such as the observed IoT traffic volume and message composition, are given before device classes with statistically different signaling behavior are identified. Finally, by characterizing the aggre- gated signaling traffic, we show that the Markov assumption, widespread in standardization and literature, regarding the aggregated arrival process for data connections does not apply in reality.}, address = {Bordeaux, France (Virtual Conference)}, author = {Geissler, Stefan and Wamser, Florian and Bauer, Wolfang and Krolikowski, Michael and Gebert, Steffen and Hoßfeld, Tobias}, booktitle = {IFIP/IEEE International Symposium on Integrated Network Management (IM 2021)}, keywords = {can}, month = {05}, title = {Signaling Traffic in Internet-of-Things Mobile Networks}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-1 %A Geissler, Stefan %A Wamser, Florian %A Bauer, Wolfang %A Krolikowski, Michael %A Gebert, Steffen %A Hoßfeld, Tobias %B IFIP/IEEE International Symposium on Integrated Network Management (IM 2021) %C Bordeaux, France (Virtual Conference) %D 2021 %T Signaling Traffic in Internet-of-Things Mobile Networks %X The Internet of Things (IoT) is expected to play an increasingly important role in next-generation mobile networks. Detailed knowledge of this type of traffic and the associated signaling in those networks is of interest to operators and standardization in order to run these networks successfully. The aim of this study is to characterize IoT signaling traffic for mobile communication networks (i) from a network operator’s point of view, (ii) at device level, and (iii) for the establishment of data connections. General statistics on signaling and device behavior, such as the observed IoT traffic volume and message composition, are given before device classes with statistically different signaling behavior are identified. Finally, by characterizing the aggre- gated signaling traffic, we show that the Markov assumption, widespread in standardization and literature, regarding the aggregated arrival process for data connections does not apply in reality.
• Quality that Matters: QoE Monitoring in Education Service Provider (ESP) Networks. Wehner, Nikolas; Seufert, Michael; Wieser, Viktoria; Casas, Pedro; Capdehourat, Germán. In IFIP/IEEE International Symposium on Integrated Network Management (IM 2021). Bordeaux, France (Virtual Conference), 2021.
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  Education Service Providers (ESPs) play a crucial role in the digitization of education as they equip students and teachers with reliable devices and provide high quality Internet access at schools. This paper investigates four months worth of continuous measurements conducted by an ESP using a largescale, passive, in-device Quality of Experience (QoE) monitoring system deployed into a nationwide network of education-purpose devices. These measurements cover more than 800 education centers and about 4000 devices, used both in schools and at home. Using this rich dataset, we present an exhaustive characterization of the browsing behavior, and a quantification of the web and video QoE in this educational context. Web QoE results showed a better performance for school Wi-Fi networks compared to home connections, suggesting that several issues may arise for ESPs due to the increasing relevance of home-schooling caused by the COVID-19 pandemic.

  @inproceedings{info3-inproceedings-2021-3, abstract = {Education Service Providers (ESPs) play a crucial role in the digitization of education as they equip students and teachers with reliable devices and provide high quality Internet access at schools. This paper investigates four months worth of continuous measurements conducted by an ESP using a largescale, passive, in-device Quality of Experience (QoE) monitoring system deployed into a nationwide network of education-purpose devices. These measurements cover more than 800 education centers and about 4000 devices, used both in schools and at home. Using this rich dataset, we present an exhaustive characterization of the browsing behavior, and a quantification of the web and video QoE in this educational context. Web QoE results showed a better performance for school Wi-Fi networks compared to home connections, suggesting that several issues may arise for ESPs due to the increasing relevance of home-schooling caused by the COVID-19 pandemic.}, address = {Bordeaux, France (Virtual Conference)}, author = {Wehner, Nikolas and Seufert, Michael and Wieser, Viktoria and Casas, Pedro and Capdehourat, Germán}, booktitle = {IFIP/IEEE International Symposium on Integrated Network Management (IM 2021)}, keywords = {ucn}, month = {05}, title = {Quality that Matters: QoE Monitoring in Education Service Provider (ESP) Networks}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-3 %A Wehner, Nikolas %A Seufert, Michael %A Wieser, Viktoria %A Casas, Pedro %A Capdehourat, Germán %B IFIP/IEEE International Symposium on Integrated Network Management (IM 2021) %C Bordeaux, France (Virtual Conference) %D 2021 %T Quality that Matters: QoE Monitoring in Education Service Provider (ESP) Networks %X Education Service Providers (ESPs) play a crucial role in the digitization of education as they equip students and teachers with reliable devices and provide high quality Internet access at schools. This paper investigates four months worth of continuous measurements conducted by an ESP using a largescale, passive, in-device Quality of Experience (QoE) monitoring system deployed into a nationwide network of education-purpose devices. These measurements cover more than 800 education centers and about 4000 devices, used both in schools and at home. Using this rich dataset, we present an exhaustive characterization of the browsing behavior, and a quantification of the web and video QoE in this educational context. Web QoE results showed a better performance for school Wi-Fi networks compared to home connections, suggesting that several issues may arise for ESPs due to the increasing relevance of home-schooling caused by the COVID-19 pandemic.
• ML-Assisted Latency Assignments in Time-Sensitive Networking. Grigorjew, Alexej; Seufert, Michael; Wehner, Nikolas; Hofmann, Jan; Hoßfeld, Tobias. In IFIP/IEEE International Symposium on Integrated Network Management (IM 2021). Bordeaux, France (Virtual Conference), 2021.
  • [ Abstract ]
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  Recent developments in industrial automation and invehicle communication have raised the requirements of real-time networking. Bus systems that were traditionally deployed in these fields cannot provide sufficient bandwidth and are now shifting towards Ethernet for their real-time communication needs. In this field, standardization efforts from the IEEE and the IETF have developed new data plane mechanisms such as shapers and schedulers, as well as control plane mechanisms such as reservation protocols to support their new requirements. However, their implementation and their optimal configuration remain an important factor for their efficiency. This work presents a machine learning framework that takes on the configuration task. Four different models are trained for the configuration of per-hop latency guarantees in a distributed resource reservation process and compared with respect to their real-time traffic capacity. The evaluation shows that all models provide good configurations for the provided scenarios, but more importantly, they represent a first step for a semi-automated configuration of parameters in Time-Sensitive Networking.

  @inproceedings{info3-inproceedings-2021-2, abstract = {Recent developments in industrial automation and invehicle communication have raised the requirements of real-time networking. Bus systems that were traditionally deployed in these fields cannot provide sufficient bandwidth and are now shifting towards Ethernet for their real-time communication needs. In this field, standardization efforts from the IEEE and the IETF have developed new data plane mechanisms such as shapers and schedulers, as well as control plane mechanisms such as reservation protocols to support their new requirements. However, their implementation and their optimal configuration remain an important factor for their efficiency. This work presents a machine learning framework that takes on the configuration task. Four different models are trained for the configuration of per-hop latency guarantees in a distributed resource reservation process and compared with respect to their real-time traffic capacity. The evaluation shows that all models provide good configurations for the provided scenarios, but more importantly, they represent a first step for a semi-automated configuration of parameters in Time-Sensitive Networking.}, address = {Bordeaux, France (Virtual Conference)}, author = {Grigorjew, Alexej and Seufert, Michael and Wehner, Nikolas and Hofmann, Jan and Hoßfeld, Tobias}, booktitle = {IFIP/IEEE International Symposium on Integrated Network Management (IM 2021)}, keywords = {kikdin}, month = {05}, title = {ML-Assisted Latency Assignments in Time-Sensitive Networking}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-2 %A Grigorjew, Alexej %A Seufert, Michael %A Wehner, Nikolas %A Hofmann, Jan %A Hoßfeld, Tobias %B IFIP/IEEE International Symposium on Integrated Network Management (IM 2021) %C Bordeaux, France (Virtual Conference) %D 2021 %T ML-Assisted Latency Assignments in Time-Sensitive Networking %X Recent developments in industrial automation and invehicle communication have raised the requirements of real-time networking. Bus systems that were traditionally deployed in these fields cannot provide sufficient bandwidth and are now shifting towards Ethernet for their real-time communication needs. In this field, standardization efforts from the IEEE and the IETF have developed new data plane mechanisms such as shapers and schedulers, as well as control plane mechanisms such as reservation protocols to support their new requirements. However, their implementation and their optimal configuration remain an important factor for their efficiency. This work presents a machine learning framework that takes on the configuration task. Four different models are trained for the configuration of per-hop latency guarantees in a distributed resource reservation process and compared with respect to their real-time traffic capacity. The evaluation shows that all models provide good configurations for the provided scenarios, but more importantly, they represent a first step for a semi-automated configuration of parameters in Time-Sensitive Networking.
• Trust but Verify: Crowdsourced Mobile Network Measurements and Statistical Validity Measures. Seufert, Anika; Wamser, Florian; Wunderer, Stefan; Hall, Andrew; Hoßfeld, Tobias. In 2021 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit). Porto, Portugal (virtual conference), 2021.
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  Network operators, regulators, and big data companies use crowdsourced measurements to study the performance of mobile networks on a large scale. Such a type of measurement is defined as the collection and processing of data measured by the crowd, here the crowd of mobile subscribers. Crowdsourced network measurements make it relatively easy and inexpensive to obtain large amounts of network data that also reflect the quality actually received by the end user. However, this measurement method also involves some uncertainties, since, for example, it is not possible to precisely control when, where and with which devices measurements are taken. Thus, there is a trade-off between the reliability of the individual measurement and the scope of the measurements. Therefore, how data of this type is analyzed is particularly important in order to obtain valid results. To address this issue, our paper defines concepts and guidelines for analyzing the validity of crowdsourced mobile network measurements. In particular, we address precision, for example the number of measurements needed to make valid statements, and also representativeness, for example the spatial and temporal distribution of the data. In addition to the formal definition of these two aspects, we illustrate the issue and possible evaluation approaches with the help of an extensive example data set. This data set consists of more than 11.7M crowdsourced mobile measurements from all over France, measured by a commercial mobile data provider. In the end, we provide an evaluation guideline and two possible use cases.

  @inproceedings{info3-inproceedings-2021-11, abstract = {Network operators, regulators, and big data companies use crowdsourced measurements to study the performance of mobile networks on a large scale. Such a type of measurement is defined as the collection and processing of data measured by the crowd, here the crowd of mobile subscribers. Crowdsourced network measurements make it relatively easy and inexpensive to obtain large amounts of network data that also reflect the quality actually received by the end user. However, this measurement method also involves some uncertainties, since, for example, it is not possible to precisely control when, where and with which devices measurements are taken. Thus, there is a trade-off between the reliability of the individual measurement and the scope of the measurements. Therefore, how data of this type is analyzed is particularly important in order to obtain valid results. To address this issue, our paper defines concepts and guidelines for analyzing the validity of crowdsourced mobile network measurements. In particular, we address precision, for example the number of measurements needed to make valid statements, and also representativeness, for example the spatial and temporal distribution of the data. In addition to the formal definition of these two aspects, we illustrate the issue and possible evaluation approaches with the help of an extensive example data set. This data set consists of more than 11.7M crowdsourced mobile measurements from all over France, measured by a commercial mobile data provider. In the end, we provide an evaluation guideline and two possible use cases.}, address = {Porto, Portugal (virtual conference)}, author = {Seufert, Anika and Wamser, Florian and Wunderer, Stefan and Hall, Andrew and Hoßfeld, Tobias}, booktitle = {2021 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit)}, keywords = {can}, month = {06}, title = {Trust but Verify: Crowdsourced Mobile Network Measurements and Statistical Validity Measures}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-11 %A Seufert, Anika %A Wamser, Florian %A Wunderer, Stefan %A Hall, Andrew %A Hoßfeld, Tobias %B 2021 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit) %C Porto, Portugal (virtual conference) %D 2021 %T Trust but Verify: Crowdsourced Mobile Network Measurements and Statistical Validity Measures %X Network operators, regulators, and big data companies use crowdsourced measurements to study the performance of mobile networks on a large scale. Such a type of measurement is defined as the collection and processing of data measured by the crowd, here the crowd of mobile subscribers. Crowdsourced network measurements make it relatively easy and inexpensive to obtain large amounts of network data that also reflect the quality actually received by the end user. However, this measurement method also involves some uncertainties, since, for example, it is not possible to precisely control when, where and with which devices measurements are taken. Thus, there is a trade-off between the reliability of the individual measurement and the scope of the measurements. Therefore, how data of this type is analyzed is particularly important in order to obtain valid results. To address this issue, our paper defines concepts and guidelines for analyzing the validity of crowdsourced mobile network measurements. In particular, we address precision, for example the number of measurements needed to make valid statements, and also representativeness, for example the spatial and temporal distribution of the data. In addition to the formal definition of these two aspects, we illustrate the issue and possible evaluation approaches with the help of an extensive example data set. This data set consists of more than 11.7M crowdsourced mobile measurements from all over France, measured by a commercial mobile data provider. In the end, we provide an evaluation guideline and two possible use cases.
• QoE Models in the Wild: Comparing Video QoE Models Using a Crowdsourced Data Set. Seufert, Anika; Wamser, Florian; Yarish, David; Macdonald, Hunter; Hoßfeld, Tobias. In 2021 13th International Conference on Quality of Multimedia Experience (QoMEX). Montreal, Canada (virtual conference), 2021.
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  Crowdsourced measurements solve the problem of being able to assess the performance of a communication network from an end-user perspective, but the new characteristics of the data pose new challenges for QoE modeling. In contrast to existing laboratory or network measurements, this type of measurement at the end-user device primarily involves taking a large number of short sample measurements, which, however, are rich in measured parameters, including many user-, application-, and device-related parameters. To test the applicability and to facilitate the integration of such data, we applied four QoE models from the literature to 290k worldwide video streaming measurements from a commercial data set from August to October 2020. In this work, we will therefore first describe the crowdsourcing video streaming data set to provide insights into the properties of video streaming KPIs in the real-world. Second, we run four popular QoE models using this data set, compare the resulting QoE scores, and derive the impact of individual KPIs for each model. We show that the models assess the QoE at least differently, but sometimes with contradicting statements. Reading this paper, it becomes evident that more work and subjective studies, based on real-world data like the one we have shown, are needed to extend the current QoE models.

  @inproceedings{info3-inproceedings-2021-12, abstract = {Crowdsourced measurements solve the problem of being able to assess the performance of a communication network from an end-user perspective, but the new characteristics of the data pose new challenges for QoE modeling. In contrast to existing laboratory or network measurements, this type of measurement at the end-user device primarily involves taking a large number of short sample measurements, which, however, are rich in measured parameters, including many user-, application-, and device-related parameters. To test the applicability and to facilitate the integration of such data, we applied four QoE models from the literature to 290k worldwide video streaming measurements from a commercial data set from August to October 2020. In this work, we will therefore first describe the crowdsourcing video streaming data set to provide insights into the properties of video streaming KPIs in the real-world. Second, we run four popular QoE models using this data set, compare the resulting QoE scores, and derive the impact of individual KPIs for each model. We show that the models assess the QoE at least differently, but sometimes with contradicting statements. Reading this paper, it becomes evident that more work and subjective studies, based on real-world data like the one we have shown, are needed to extend the current QoE models.}, address = {Montreal, Canada (virtual conference)}, author = {Seufert, Anika and Wamser, Florian and Yarish, David and Macdonald, Hunter and Hoßfeld, Tobias}, booktitle = {2021 13th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {can}, month = {06}, title = {QoE Models in the Wild: Comparing Video QoE Models Using a Crowdsourced Data Set}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-12 %A Seufert, Anika %A Wamser, Florian %A Yarish, David %A Macdonald, Hunter %A Hoßfeld, Tobias %B 2021 13th International Conference on Quality of Multimedia Experience (QoMEX) %C Montreal, Canada (virtual conference) %D 2021 %T QoE Models in the Wild: Comparing Video QoE Models Using a Crowdsourced Data Set %X Crowdsourced measurements solve the problem of being able to assess the performance of a communication network from an end-user perspective, but the new characteristics of the data pose new challenges for QoE modeling. In contrast to existing laboratory or network measurements, this type of measurement at the end-user device primarily involves taking a large number of short sample measurements, which, however, are rich in measured parameters, including many user-, application-, and device-related parameters. To test the applicability and to facilitate the integration of such data, we applied four QoE models from the literature to 290k worldwide video streaming measurements from a commercial data set from August to October 2020. In this work, we will therefore first describe the crowdsourcing video streaming data set to provide insights into the properties of video streaming KPIs in the real-world. Second, we run four popular QoE models using this data set, compare the resulting QoE scores, and derive the impact of individual KPIs for each model. We show that the models assess the QoE at least differently, but sometimes with contradicting statements. Reading this paper, it becomes evident that more work and subjective studies, based on real-world data like the one we have shown, are needed to extend the current QoE models.
• High Performance Network Metadata Extraction Using P4 for ML-Based Intrusion Detection Systems. Gray, Nicholas; Dietz, Katharina; Seufert, Michael; Hoßfeld, Tobias. In 22nd International Conference on High Performance Switching and Routing (HPSR). Paris, France (Virtual Conference), 2021.
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  @inproceedings{info3-inproceedings-2021-8, address = {Paris, France (Virtual Conference)}, author = {Gray, Nicholas and Dietz, Katharina and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {22nd International Conference on High Performance Switching and Routing (HPSR)}, keywords = {ucn}, month = {06}, title = {High Performance Network Metadata Extraction Using P4 for ML-Based Intrusion Detection Systems}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-8 %A Gray, Nicholas %A Dietz, Katharina %A Seufert, Michael %A Hoßfeld, Tobias %B 22nd International Conference on High Performance Switching and Routing (HPSR) %C Paris, France (Virtual Conference) %D 2021 %T High Performance Network Metadata Extraction Using P4 for ML-Based Intrusion Detection Systems
• Dynamic Real-Time Stream Reservation with TAS and Shared Time Windows. Grigorjew, Alexej; Gray, Nicholas; Hoßfeld, Tobias. In 2nd International Workshop on Time-Sensitive and Deterministic Networking (TENSOR). 2021.
  • [ Abstract ]
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  Motivated by new use cases such as industrial automation and in-vehicle communication, Time-Sensitive Networking is further improving the layer~2 standards for real-time communication in Ethernet networks. As periodic traffic is a common requirement in such scenarios, the Time Aware Shaper (TAS) is a highly popular mechanism that allows the realization of real-time guarantees in synchronized networks. Most applications in literature suggest to configure the TAS for full stream isolation such that the lowest delays can be achieved. However, this ``zero-queuing'' strategy requires a high amount of computational resources and time, as the configuration of the gate control lists of each port is a complex task, which is not suitable for scenarios with dynamically changing requirements. This paper presents a novel approach with shared time windows. In combination with stream reservation techniques that are commonly applied for asynchronous mechanisms, the network is able to accept new streams during operation without complex reconfiguration, while still benefiting from some degree of isolation compared to conventional asynchronous shapers. The evaluation shows that, given the right circumstances, the number of accepted real-time streams can be improved significantly.

  @inproceedings{info3-inproceedings-2021-7, abstract = {Motivated by new use cases such as industrial automation and in-vehicle communication, Time-Sensitive Networking is further improving the layer 2 standards for real-time communication in Ethernet networks. As periodic traffic is a common requirement in such scenarios, the Time Aware Shaper (TAS) is a highly popular mechanism that allows the realization of real-time guarantees in synchronized networks. Most applications in literature suggest to configure the TAS for full stream isolation such that the lowest delays can be achieved. However, this ``zero-queuing'' strategy requires a high amount of computational resources and time, as the configuration of the gate control lists of each port is a complex task, which is not suitable for scenarios with dynamically changing requirements. This paper presents a novel approach with shared time windows. In combination with stream reservation techniques that are commonly applied for asynchronous mechanisms, the network is able to accept new streams during operation without complex reconfiguration, while still benefiting from some degree of isolation compared to conventional asynchronous shapers. The evaluation shows that, given the right circumstances, the number of accepted real-time streams can be improved significantly.}, author = {Grigorjew, Alexej and Gray, Nicholas and Hoßfeld, Tobias}, booktitle = {2nd International Workshop on Time-Sensitive and Deterministic Networking (TENSOR)}, keywords = {ngn}, month = {06}, title = {Dynamic Real-Time Stream Reservation with TAS and Shared Time Windows}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-7 %A Grigorjew, Alexej %A Gray, Nicholas %A Hoßfeld, Tobias %B 2nd International Workshop on Time-Sensitive and Deterministic Networking (TENSOR) %D 2021 %T Dynamic Real-Time Stream Reservation with TAS and Shared Time Windows %X Motivated by new use cases such as industrial automation and in-vehicle communication, Time-Sensitive Networking is further improving the layer~2 standards for real-time communication in Ethernet networks. As periodic traffic is a common requirement in such scenarios, the Time Aware Shaper (TAS) is a highly popular mechanism that allows the realization of real-time guarantees in synchronized networks. Most applications in literature suggest to configure the TAS for full stream isolation such that the lowest delays can be achieved. However, this ``zero-queuing'' strategy requires a high amount of computational resources and time, as the configuration of the gate control lists of each port is a complex task, which is not suitable for scenarios with dynamically changing requirements. This paper presents a novel approach with shared time windows. In combination with stream reservation techniques that are commonly applied for asynchronous mechanisms, the network is able to accept new streams during operation without complex reconfiguration, while still benefiting from some degree of isolation compared to conventional asynchronous shapers. The evaluation shows that, given the right circumstances, the number of accepted real-time streams can be improved significantly.
• How are your Apps Doing? QoE Inference and Analysis in Mobile Devices. Wehner, Nikolas; Seufert, Michael; Schüler, Joshua; Casas, Pedro; Hoßfeld, Tobias. In 17th International Conference on Network and Service Management (CNSM). Izmir, Turkey (Virtual Conference), 2021.
  • [ Abstract ]
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  Web browsing has become the most important application of the Internet for the end user. When it comes to mobile devices, web services are mainly accessed through apps. This paper tackles the problem of Web Quality of Experience (QoE) in mobile devices, with a specific focus on apps QoE monitoring and analysis, using in-network (encrypted) traffic measurements. Measuring apps QoE is complex, not only from an instrumentation point of view, but also from the heterogeneity of user interactions which might realize substantially different user experience. To this end, we conduct a feasibility study on four specific and popular Android apps and their corresponding web services. Our test automation framework emulates and measures different user interactions commonly executed during an app session, including the app startup, clicking, scrolling, and searching. The resulting traffic is characterized on different dimensions, and machine learning models are trained to identify web services, apps, and user interactions, and to infer their QoE. The proposed models can correctly identify the specific web service and app in 86% of the cases and accurately estimate the associated QoE with small errors. Our preliminary study represents a first step towards an in-network, web QoE monitoring solution for mobile-device apps.

  @inproceedings{info3-inproceedings-2021-15, abstract = {Web browsing has become the most important application of the Internet for the end user. When it comes to mobile devices, web services are mainly accessed through apps. This paper tackles the problem of Web Quality of Experience (QoE) in mobile devices, with a specific focus on apps QoE monitoring and analysis, using in-network (encrypted) traffic measurements. Measuring apps QoE is complex, not only from an instrumentation point of view, but also from the heterogeneity of user interactions which might realize substantially different user experience. To this end, we conduct a feasibility study on four specific and popular Android apps and their corresponding web services. Our test automation framework emulates and measures different user interactions commonly executed during an app session, including the app startup, clicking, scrolling, and searching. The resulting traffic is characterized on different dimensions, and machine learning models are trained to identify web services, apps, and user interactions, and to infer their QoE. The proposed models can correctly identify the specific web service and app in 86% of the cases and accurately estimate the associated QoE with small errors. Our preliminary study represents a first step towards an in-network, web QoE monitoring solution for mobile-device apps.}, address = {Izmir, Turkey (Virtual Conference)}, author = {Wehner, Nikolas and Seufert, Michael and Schüler, Joshua and Casas, Pedro and Hoßfeld, Tobias}, booktitle = {17th International Conference on Network and Service Management (CNSM)}, keywords = {ucn}, month = 10, title = {How are your Apps Doing? QoE Inference and Analysis in Mobile Devices}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-15 %A Wehner, Nikolas %A Seufert, Michael %A Schüler, Joshua %A Casas, Pedro %A Hoßfeld, Tobias %B 17th International Conference on Network and Service Management (CNSM) %C Izmir, Turkey (Virtual Conference) %D 2021 %T How are your Apps Doing? QoE Inference and Analysis in Mobile Devices %X Web browsing has become the most important application of the Internet for the end user. When it comes to mobile devices, web services are mainly accessed through apps. This paper tackles the problem of Web Quality of Experience (QoE) in mobile devices, with a specific focus on apps QoE monitoring and analysis, using in-network (encrypted) traffic measurements. Measuring apps QoE is complex, not only from an instrumentation point of view, but also from the heterogeneity of user interactions which might realize substantially different user experience. To this end, we conduct a feasibility study on four specific and popular Android apps and their corresponding web services. Our test automation framework emulates and measures different user interactions commonly executed during an app session, including the app startup, clicking, scrolling, and searching. The resulting traffic is characterized on different dimensions, and machine learning models are trained to identify web services, apps, and user interactions, and to infer their QoE. The proposed models can correctly identify the specific web service and app in 86% of the cases and accurately estimate the associated QoE with small errors. Our preliminary study represents a first step towards an in-network, web QoE monitoring solution for mobile-device apps.
• On Inter-Rater Reliability for Crowdsourced QoE. Hoßfeld, Tobias; Seufert, Michael; Naderi, Babak. In 13th International Conference on Quality of Multimedia Experience (QoMEX). Montreal, Canada (Virtual Conference), 2021.
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  @inproceedings{info3-inproceedings-2021-9, address = {Montreal, Canada (Virtual Conference)}, author = {Hoßfeld, Tobias and Seufert, Michael and Naderi, Babak}, booktitle = {13th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ucn}, month = {06}, title = {On Inter-Rater Reliability for Crowdsourced QoE}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-9 %A Hoßfeld, Tobias %A Seufert, Michael %A Naderi, Babak %B 13th International Conference on Quality of Multimedia Experience (QoMEX) %C Montreal, Canada (Virtual Conference) %D 2021 %T On Inter-Rater Reliability for Crowdsourced QoE
• Improving LoRaWAN’s Successful Information Transmission Rate with Redundancy. Loh, Frank; Raffeck, Simon; Metzger, Florian; Hoßfeld, Tobias. In 17th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob). 2021.
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  The adaptation of Internet of Things in our everyday life shows different new demands and challenges. One of the fastest growing technologies in this context are Low Power Wide Area Networks with LoRaWAN as one of their most prominent representatives. The promise of this technology is to transmit sensor data over large distances with very little energy consumption. But transmission behavior, and especially overhead and collision probability, must be studied in detail to improve transmission quality and energy consumption due to the random access nature of LoRaWAN. Because of that, this work investigates the LoRaWAN channel capacity by analyzing the transmission overhead, the collision probability, and the data loss. At the end, an energy consumption comparison is done. The contribution is a novel approach based on aggregation and retransmission that shows a decreased data loss of up to 20% compared to the currently used random channel access.

  @inproceedings{info3-inproceedings-2021-19, abstract = {The adaptation of Internet of Things in our everyday life shows different new demands and challenges. One of the fastest growing technologies in this context are Low Power Wide Area Networks with LoRaWAN as one of their most prominent representatives. The promise of this technology is to transmit sensor data over large distances with very little energy consumption. But transmission behavior, and especially overhead and collision probability, must be studied in detail to improve transmission quality and energy consumption due to the random access nature of LoRaWAN. Because of that, this work investigates the LoRaWAN channel capacity by analyzing the transmission overhead, the collision probability, and the data loss. At the end, an energy consumption comparison is done. The contribution is a novel approach based on aggregation and retransmission that shows a decreased data loss of up to 20% compared to the currently used random channel access.}, author = {Loh, Frank and Raffeck, Simon and Metzger, Florian and Hoßfeld, Tobias}, booktitle = {17th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob)}, keywords = {5mart}, month = 10, title = {Improving LoRaWAN’s Successful Information Transmission Rate with Redundancy}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-19 %A Loh, Frank %A Raffeck, Simon %A Metzger, Florian %A Hoßfeld, Tobias %B 17th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob) %D 2021 %T Improving LoRaWAN’s Successful Information Transmission Rate with Redundancy %X The adaptation of Internet of Things in our everyday life shows different new demands and challenges. One of the fastest growing technologies in this context are Low Power Wide Area Networks with LoRaWAN as one of their most prominent representatives. The promise of this technology is to transmit sensor data over large distances with very little energy consumption. But transmission behavior, and especially overhead and collision probability, must be studied in detail to improve transmission quality and energy consumption due to the random access nature of LoRaWAN. Because of that, this work investigates the LoRaWAN channel capacity by analyzing the transmission overhead, the collision probability, and the data loss. At the end, an energy consumption comparison is done. The contribution is a novel approach based on aggregation and retransmission that shows a decreased data loss of up to 20% compared to the currently used random channel access.
• Relationship Status: It’s Complicated. Using APM as a QoE-qualifying Tempo Metric. Metzger, Florian; Stulier, Norman; Borchert, Kathrin; Hirth, Matthias. In Proceedings of the 13th International Conference on Quality of Multimedia Experience (QoMEX 2021). 2021.
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  @inproceedings{info3-inproceedings-2021-13, author = {Metzger, Florian and Stulier, Norman and Borchert, Kathrin and Hirth, Matthias}, booktitle = {Proceedings of the 13th International Conference on Quality of Multimedia Experience (QoMEX 2021)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Relationship Status: It's Complicated. Using APM as a QoE-qualifying Tempo Metric}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-13 %A Metzger, Florian %A Stulier, Norman %A Borchert, Kathrin %A Hirth, Matthias %B Proceedings of the 13th International Conference on Quality of Multimedia Experience (QoMEX 2021) %D 2021 %T Relationship Status: It's Complicated. Using APM as a QoE-qualifying Tempo Metric
• Discrete-time Analysis of Multicomponent GI/GI/1 Queueing Networks. Geissler, Stefan; Lange, Stanislav; Tran-Gia, Phuoc; Hoßfeld, Tobias. In Conference on Networked Systems (NetSys). 2021.
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  In this work, we provide initial insights regarding the error introduced into multicomponent queueing systems by assuming the departure processes of arbitrary GI/GI/1-∞ queues to be renewal processes. To this end, we compute the sojourn time distribution as well as departure distributions of a linear chain of queueing components and compare the results to a simulation of the same system. By applying the renewal approximation, potential autocorrelations of the departure processes are lost. We investigate the magnitude of this error regarding both the sojourn time as well as interdeparture time distributions for a broad set of parameters. Although more indepth studies are needed, our results show that both distributions can be closely approximated, which allows the application of the model to asses the performance of real world NFV function chains.

  @inproceedings{info3-inproceedings-2021-4, abstract = {In this work, we provide initial insights regarding the error introduced into multicomponent queueing systems by assuming the departure processes of arbitrary GI/GI/1-∞ queues to be renewal processes. To this end, we compute the sojourn time distribution as well as departure distributions of a linear chain of queueing components and compare the results to a simulation of the same system. By applying the renewal approximation, potential autocorrelations of the departure processes are lost. We investigate the magnitude of this error regarding both the sojourn time as well as interdeparture time distributions for a broad set of parameters. Although more indepth studies are needed, our results show that both distributions can be closely approximated, which allows the application of the model to asses the performance of real world NFV function chains.}, author = {Geissler, Stefan and Lange, Stanislav and Tran-Gia, Phuoc and Hoßfeld, Tobias}, booktitle = {Conference on Networked Systems (NetSys)}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Discrete-time Analysis of Multicomponent GI/GI/1 Queueing Networks}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-4 %A Geissler, Stefan %A Lange, Stanislav %A Tran-Gia, Phuoc %A Hoßfeld, Tobias %B Conference on Networked Systems (NetSys) %D 2021 %T Discrete-time Analysis of Multicomponent GI/GI/1 Queueing Networks %X In this work, we provide initial insights regarding the error introduced into multicomponent queueing systems by assuming the departure processes of arbitrary GI/GI/1-∞ queues to be renewal processes. To this end, we compute the sojourn time distribution as well as departure distributions of a linear chain of queueing components and compare the results to a simulation of the same system. By applying the renewal approximation, potential autocorrelations of the departure processes are lost. We investigate the magnitude of this error regarding both the sojourn time as well as interdeparture time distributions for a broad set of parameters. Although more indepth studies are needed, our results show that both distributions can be closely approximated, which allows the application of the model to asses the performance of real world NFV function chains.
• Machine Learning-based Service Function Chain over UAVs: Resource Profiling and Framework. TrungKien, Nguyen; Hoang Anh, Vu; Dinh Phong, Vu; Ngoc Minh, Nguyen; Huu Thanh, Nguyen. In 2021 31st International Telecommunication Networks and Applications Conference (ITNAC). Sydney, Australia, 2021.
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  @inproceedings{info3-inproceedings-2021-21, address = {Sydney, Australia}, author = {TrungKien, Nguyen and Hoang Anh, Vu and Dinh Phong, Vu and Ngoc Minh, Nguyen and Huu Thanh, Nguyen}, booktitle = {2021 31st International Telecommunication Networks and Applications Conference (ITNAC)}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Machine Learning-based Service Function Chain over UAVs: Resource Profiling and Framework}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-21 %A TrungKien, Nguyen %A Hoang Anh, Vu %A Dinh Phong, Vu %A Ngoc Minh, Nguyen %A Huu Thanh, Nguyen %B 2021 31st International Telecommunication Networks and Applications Conference (ITNAC) %C Sydney, Australia %D 2021 %T Machine Learning-based Service Function Chain over UAVs: Resource Profiling and Framework
• Robust Gateway Placement for Scalable LoRaWAN. Loh, Frank; Bau, Dominique; Zink, Johannes; Wolff, Alexander; Hoßfeld, Tobias. In 13th IFIP Wireless and Mobile Networking Conference (WMNC). 2021.
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  Many exciting applications are currently emerging due to the use of technology from the Internet of Things (IoT) in Smart Cities. In recent years, Long Range Wide Area Networks (LoRaWANs) have become one of the main technologies in this field due to long distance coverage, low power consumption sensors, and economic reasons. So far, LoRaWANs have been planned and deployed mainly with the aim of minimizing the number of gateways, while still providing coverage in a geographic area. Packet collisions and future traffic have not been considered. In contrast, we present a gateway placement strategy that is robust against an increase in the number of sensors and in the network load. To this end, we modify an existing local search algorithm for a geometric set cover problem such that it takes the capacities of gateways into account. If we set these capacities below the maximum, the network can accommodate additional sensors in the future. Moreover, our algorithm can extend the initial placement once the capacities are exhausted.

  @inproceedings{info3-inproceedings-2021-20, abstract = {Many exciting applications are currently emerging due to the use of technology from the Internet of Things (IoT) in Smart Cities. In recent years, Long Range Wide Area Networks (LoRaWANs) have become one of the main technologies in this field due to long distance coverage, low power consumption sensors, and economic reasons. So far, LoRaWANs have been planned and deployed mainly with the aim of minimizing the number of gateways, while still providing coverage in a geographic area. Packet collisions and future traffic have not been considered. In contrast, we present a gateway placement strategy that is robust against an increase in the number of sensors and in the network load. To this end, we modify an existing local search algorithm for a geometric set cover problem such that it takes the capacities of gateways into account. If we set these capacities below the maximum, the network can accommodate additional sensors in the future. Moreover, our algorithm can extend the initial placement once the capacities are exhausted.}, author = {Loh, Frank and Bau, Dominique and Zink, Johannes and Wolff, Alexander and Hoßfeld, Tobias}, booktitle = {13th IFIP Wireless and Mobile Networking Conference (WMNC)}, keywords = {5mart}, month = 10, title = {Robust Gateway Placement for Scalable LoRaWAN}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-20 %A Loh, Frank %A Bau, Dominique %A Zink, Johannes %A Wolff, Alexander %A Hoßfeld, Tobias %B 13th IFIP Wireless and Mobile Networking Conference (WMNC) %D 2021 %T Robust Gateway Placement for Scalable LoRaWAN %X Many exciting applications are currently emerging due to the use of technology from the Internet of Things (IoT) in Smart Cities. In recent years, Long Range Wide Area Networks (LoRaWANs) have become one of the main technologies in this field due to long distance coverage, low power consumption sensors, and economic reasons. So far, LoRaWANs have been planned and deployed mainly with the aim of minimizing the number of gateways, while still providing coverage in a geographic area. Packet collisions and future traffic have not been considered. In contrast, we present a gateway placement strategy that is robust against an increase in the number of sensors and in the network load. To this end, we modify an existing local search algorithm for a geometric set cover problem such that it takes the capacities of gateways into account. If we set these capacities below the maximum, the network can accommodate additional sensors in the future. Moreover, our algorithm can extend the initial placement once the capacities are exhausted.
• Machine-Learning Based Prediction of Next HTTP Request Arrival Time in Adaptive Video Streaming. Pimpinella, Andrea; Redondi, Alessandro E.C.; Loh, Frank; Seufert, Michael. In 3rd International Workshop on High-Precision, Predictable, and Low-Latency Networking (HiPNet). Izmir, Turkey (Virtual Conference), 2021.
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  @inproceedings{info3-inproceedings-2021-18, address = {Izmir, Turkey (Virtual Conference)}, author = {Pimpinella, Andrea and Redondi, Alessandro E.C. and Loh, Frank and Seufert, Michael}, booktitle = {3rd International Workshop on High-Precision, Predictable, and Low-Latency Networking (HiPNet)}, keywords = {ucn}, month = 10, title = {Machine-Learning Based Prediction of Next HTTP Request Arrival Time in Adaptive Video Streaming}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-18 %A Pimpinella, Andrea %A Redondi, Alessandro E.C. %A Loh, Frank %A Seufert, Michael %B 3rd International Workshop on High-Precision, Predictable, and Low-Latency Networking (HiPNet) %C Izmir, Turkey (Virtual Conference) %D 2021 %T Machine-Learning Based Prediction of Next HTTP Request Arrival Time in Adaptive Video Streaming
• Mobile Web and App QoE Monitoring for ISPs - from Encrypted Traffic to Speed Index through Machine Learning. Casas, Pedro; Wassermann, Sarah; Wehner, Nikolas; Seufert, Michael; Schüler, Joshua; Hoßfeld, Tobias. In 13th Wireless and Mobile Networking Conference (WMNC), Best Paper Award. Montreal, Canada (Virtual Conference), 2021.
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  @inproceedings{info3-inproceedings-2021-17, address = {Montreal, Canada (Virtual Conference)}, author = {Casas, Pedro and Wassermann, Sarah and Wehner, Nikolas and Seufert, Michael and Schüler, Joshua and Hoßfeld, Tobias}, booktitle = {13th Wireless and Mobile Networking Conference (WMNC), Best Paper Award}, keywords = {ucn}, month = 10, title = {Mobile Web and App QoE Monitoring for ISPs - from Encrypted Traffic to Speed Index through Machine Learning}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-17 %A Casas, Pedro %A Wassermann, Sarah %A Wehner, Nikolas %A Seufert, Michael %A Schüler, Joshua %A Hoßfeld, Tobias %B 13th Wireless and Mobile Networking Conference (WMNC), Best Paper Award %C Montreal, Canada (Virtual Conference) %D 2021 %T Mobile Web and App QoE Monitoring for ISPs - from Encrypted Traffic to Speed Index through Machine Learning
• Browser Fingerprinting: How to Protect Machine Learning Models and Data with Differential Privacy?. Dietz, Katharina; Mühlhauser, Michael; Seufert, Michael; Gray, Nicholas; Hoßfeld, Tobias; Herrmann, Dominik. In 1st International Workshop on Machine Learning in Networking (MaLeNe) as part of NetSys’21. Lübeck, Germany (Virtual Conference), 2021.
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  @inproceedings{info3-inproceedings-2021-16, address = {Lübeck, Germany (Virtual Conference)}, author = {Dietz, Katharina and Mühlhauser, Michael and Seufert, Michael and Gray, Nicholas and Hoßfeld, Tobias and Herrmann, Dominik}, booktitle = {1st International Workshop on Machine Learning in Networking (MaLeNe) as part of NetSys'21}, keywords = {ucn}, month = {09}, title = {Browser Fingerprinting: How to Protect Machine Learning Models and Data with Differential Privacy?}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-16 %A Dietz, Katharina %A Mühlhauser, Michael %A Seufert, Michael %A Gray, Nicholas %A Hoßfeld, Tobias %A Herrmann, Dominik %B 1st International Workshop on Machine Learning in Networking (MaLeNe) as part of NetSys'21 %C Lübeck, Germany (Virtual Conference) %D 2021 %T Browser Fingerprinting: How to Protect Machine Learning Models and Data with Differential Privacy?
• On Machine Learning based Video QoE Estimation Across Different Networks. Orsolic, Irena; Seufert, Michael. In 16th International Conference on Telecommunications (ConTEL), Best Paper Award. Zagreb, Croatia (Virtual Conference), 2021.
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  @inproceedings{info3-inproceedings-2021-10, address = {Zagreb, Croatia (Virtual Conference)}, author = {Orsolic, Irena and Seufert, Michael}, booktitle = {16th International Conference on Telecommunications (ConTEL), Best Paper Award}, keywords = {ucn}, month = {07}, title = {On Machine Learning based Video QoE Estimation Across Different Networks}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-10 %A Orsolic, Irena %A Seufert, Michael %B 16th International Conference on Telecommunications (ConTEL), Best Paper Award %C Zagreb, Croatia (Virtual Conference) %D 2021 %T On Machine Learning based Video QoE Estimation Across Different Networks

• Personal Task Design Preferences of Crowdworkers. Hirth, Matthias; Borchert, Kathrin; de Moor, Katrien; Borst, Vanessa; Hoßfeld, Tobias. In 12th International Conference on Quality of Multimedia Experience (QoMEX). Athlone, Ireland, 2020.
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  @inproceedings{info3-inproceedings-2020-5, address = {Athlone, Ireland}, author = {Hirth, Matthias and Borchert, Kathrin and de Moor, Katrien and Borst, Vanessa and Hoßfeld, Tobias}, booktitle = {12th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ua-net}, month = {05}, title = {Personal Task Design Preferences of Crowdworkers}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-5 %A Hirth, Matthias %A Borchert, Kathrin %A de Moor, Katrien %A Borst, Vanessa %A Hoßfeld, Tobias %B 12th International Conference on Quality of Multimedia Experience (QoMEX) %C Athlone, Ireland %D 2020 %T Personal Task Design Preferences of Crowdworkers
• Simulative Evaluation of KPIs in SDN for Topology Classification and Performance Prediction Models. Gray, Nicholas; Dietz, Katharina; Hoßfeld, Tobias. In 2020 16th International Conference on Network and Service Management (CNSM). 2020.
  • [ Abstract ]
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  • [ EndNote ]
  In recent years Software-defined Networking (SDN) has gained increased popularity by reducing the complexity of management operations and increasing the performance of networks. As a result, the number of purchasable SDN devices and their deployment in real world network constantly rises, making a thorough understanding of their behaviors and interactions even more important. In this work we analyze distributed controller architectures via simulation, identify Key Performance Indicators (KPIs), classify various network topologies with respect to their impact on SDN, as well as create a prediction model to estimate the overall performance of the overall SDN ecosystem, which can be used for network planning.

  @inproceedings{info3-inproceedings-2020-15, abstract = {In recent years Software-defined Networking (SDN) has gained increased popularity by reducing the complexity of management operations and increasing the performance of networks. As a result, the number of purchasable SDN devices and their deployment in real world network constantly rises, making a thorough understanding of their behaviors and interactions even more important. In this work we analyze distributed controller architectures via simulation, identify Key Performance Indicators (KPIs), classify various network topologies with respect to their impact on SDN, as well as create a prediction model to estimate the overall performance of the overall SDN ecosystem, which can be used for network planning.}, author = {Gray, Nicholas and Dietz, Katharina and Hoßfeld, Tobias}, booktitle = {2020 16th International Conference on Network and Service Management (CNSM)}, keywords = {sys:hidden:inproceedings}, title = {Simulative Evaluation of KPIs in SDN for Topology Classification and Performance Prediction Models}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-15 %A Gray, Nicholas %A Dietz, Katharina %A Hoßfeld, Tobias %B 2020 16th International Conference on Network and Service Management (CNSM) %D 2020 %T Simulative Evaluation of KPIs in SDN for Topology Classification and Performance Prediction Models %X In recent years Software-defined Networking (SDN) has gained increased popularity by reducing the complexity of management operations and increasing the performance of networks. As a result, the number of purchasable SDN devices and their deployment in real world network constantly rises, making a thorough understanding of their behaviors and interactions even more important. In this work we analyze distributed controller architectures via simulation, identify Key Performance Indicators (KPIs), classify various network topologies with respect to their impact on SDN, as well as create a prediction model to estimate the overall performance of the overall SDN ecosystem, which can be used for network planning.
• Optimizing HAS for 360-Degree Videos. Moldovan, Christian; Loh, Frank; Seufert, Michael; Hoßfeld, Tobias. In 5th IEEE/IFIP International Workshop on Analytics for Network and Service Management (AnNet). Budapest, Hungary, 2020.
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  @inproceedings{info3-inproceedings-2020-1, address = {Budapest, Hungary}, author = {Moldovan, Christian and Loh, Frank and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {5th IEEE/IFIP International Workshop on Analytics for Network and Service Management (AnNet)}, keywords = {net-man}, month = {04}, title = {Optimizing HAS for 360-Degree Videos}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-1 %A Moldovan, Christian %A Loh, Frank %A Seufert, Michael %A Hoßfeld, Tobias %B 5th IEEE/IFIP International Workshop on Analytics for Network and Service Management (AnNet) %C Budapest, Hungary %D 2020 %T Optimizing HAS for 360-Degree Videos
• Is the Uplink Enough? Estimating Video Stalls from Encrypted Network Traffic. Loh, Frank; Wamser, Florian; Moldovan, Christian; Zeidler, Bernd; Tsilimantos, Dimitrios; Valentin, Stefan; Hoßfeld, Tobias. In 32th IEEE/IFIP Network Operations and Management Symposium. Budapest, Hungary, 2020.
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  Today’s traffic projections speak of almost 58 % video traffic across the Internet. Nearly all video traffic is encrypted, accounting for more than 50 % encrypted traffic worldwide. To analyze video traffic today, or even estimate its quality in the network, a deep look into the traffic characteristics has to be done. But then, important quality metrics from the traffic behavior can be derived. Based on extensive measurements we show in this work how to measure and estimate video stalls for mobile adaptive streaming. The underlying dataset includes more than 900 hours of video footage from the native YouTube app, measured over 18 different videos in 56 network scenarios in two cities in Europe. We outline a possible approach to estimate the video playback buffer size based on uplink video chunk requests in real-time to break down the video stalls. This work is intended as a tool for network operators to receive further knowledge of the characteristics of video streaming traffic to quantify the most important QoE degradation factors of one of the most important applications today.

  @inproceedings{info3-inproceedings-2020-2, abstract = {Today’s traffic projections speak of almost 58 % video traffic across the Internet. Nearly all video traffic is encrypted, accounting for more than 50 % encrypted traffic worldwide. To analyze video traffic today, or even estimate its quality in the network, a deep look into the traffic characteristics has to be done. But then, important quality metrics from the traffic behavior can be derived. Based on extensive measurements we show in this work how to measure and estimate video stalls for mobile adaptive streaming. The underlying dataset includes more than 900 hours of video footage from the native YouTube app, measured over 18 different videos in 56 network scenarios in two cities in Europe. We outline a possible approach to estimate the video playback buffer size based on uplink video chunk requests in real-time to break down the video stalls. This work is intended as a tool for network operators to receive further knowledge of the characteristics of video streaming traffic to quantify the most important QoE degradation factors of one of the most important applications today.}, address = {Budapest, Hungary}, author = {Loh, Frank and Wamser, Florian and Moldovan, Christian and Zeidler, Bernd and Tsilimantos, Dimitrios and Valentin, Stefan and Hoßfeld, Tobias}, booktitle = {32th IEEE/IFIP Network Operations and Management Symposium}, keywords = {can}, month = {04}, title = {Is the Uplink Enough? Estimating Video Stalls from Encrypted Network Traffic}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-2 %A Loh, Frank %A Wamser, Florian %A Moldovan, Christian %A Zeidler, Bernd %A Tsilimantos, Dimitrios %A Valentin, Stefan %A Hoßfeld, Tobias %B 32th IEEE/IFIP Network Operations and Management Symposium %C Budapest, Hungary %D 2020 %T Is the Uplink Enough? Estimating Video Stalls from Encrypted Network Traffic %X Today’s traffic projections speak of almost 58 % video traffic across the Internet. Nearly all video traffic is encrypted, accounting for more than 50 % encrypted traffic worldwide. To analyze video traffic today, or even estimate its quality in the network, a deep look into the traffic characteristics has to be done. But then, important quality metrics from the traffic behavior can be derived. Based on extensive measurements we show in this work how to measure and estimate video stalls for mobile adaptive streaming. The underlying dataset includes more than 900 hours of video footage from the native YouTube app, measured over 18 different videos in 56 network scenarios in two cities in Europe. We outline a possible approach to estimate the video playback buffer size based on uplink video chunk requests in real-time to break down the video stalls. This work is intended as a tool for network operators to receive further knowledge of the characteristics of video streaming traffic to quantify the most important QoE degradation factors of one of the most important applications today.
• Don’t Stop the Music: Crowdsourced QoE Assessment of Music Streaming with Stalling. Schwind, Anika; Moldovan, Christian; Janiak, Tim; Dworschak, Nemo-Dario; Hoßfeld, Tobias. In 12th International Conference on Quality of Multimedia Experience (QoMEX). Athlone, Ireland, 2020.
  • [ Abstract ]
  • [ BibTeX ]
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  Streaming made a lasting effect on the way our society consumes media in the last decade. While due to streaming the way we listen to music and podcasts has changed drastically, there are very few studies about its Quality of Experience (QoE) and possible influence factors. From video QoE studies, we know that, for example, undesirable stops of the stream (stalling events) have a significant impact on QoE. However, the way in which music and video streaming is consumed differs significantly, as music is often played in the background, and thus, the influence of stalling could be significantly different. Thus, this work evaluates the impact of stalling on music streaming QoE. Therefore, we conduct two crowdsourced user studies: In the first study, users have to rate four songs with different stalling patterns and evaluate the degree of impairments. Afterwards, we compare the ratings to the results of a lab study and show that they are highly correlated, and that crowdsourcing is a suitable way of measuring music streaming QoE. In addition, we conduct a second crowdsourcing study to investigate the influence of the user's attentiveness on QoE. Here, participants have to listen to one song with two stalling events, while one half of them had to transcribe a handwritten text with music playing in the background. The attentiveness shows no influence on the perceived streaming quality, but it shows a significant influence on the perceived quality degradation due to stalling events. Furthermore, considerably more stalling events were missed for workers who focused on the transcription. These results are an important step towards establishing new methods for investigating QoE in multimedia.

  @inproceedings{info3-inproceedings-2020-7, abstract = {Streaming made a lasting effect on the way our society consumes media in the last decade. While due to streaming the way we listen to music and podcasts has changed drastically, there are very few studies about its Quality of Experience (QoE) and possible influence factors. From video QoE studies, we know that, for example, undesirable stops of the stream (stalling events) have a significant impact on QoE. However, the way in which music and video streaming is consumed differs significantly, as music is often played in the background, and thus, the influence of stalling could be significantly different. Thus, this work evaluates the impact of stalling on music streaming QoE. Therefore, we conduct two crowdsourced user studies: In the first study, users have to rate four songs with different stalling patterns and evaluate the degree of impairments. Afterwards, we compare the ratings to the results of a lab study and show that they are highly correlated, and that crowdsourcing is a suitable way of measuring music streaming QoE. In addition, we conduct a second crowdsourcing study to investigate the influence of the user's attentiveness on QoE. Here, participants have to listen to one song with two stalling events, while one half of them had to transcribe a handwritten text with music playing in the background. The attentiveness shows no influence on the perceived streaming quality, but it shows a significant influence on the perceived quality degradation due to stalling events. Furthermore, considerably more stalling events were missed for workers who focused on the transcription. These results are an important step towards establishing new methods for investigating QoE in multimedia.}, address = {Athlone, Ireland}, author = {Schwind, Anika and Moldovan, Christian and Janiak, Tim and Dworschak, Nemo-Dario and Hoßfeld, Tobias}, booktitle = {12th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ua-net}, month = {05}, title = {Don’t Stop the Music: Crowdsourced QoE Assessment of Music Streaming with Stalling}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-7 %A Schwind, Anika %A Moldovan, Christian %A Janiak, Tim %A Dworschak, Nemo-Dario %A Hoßfeld, Tobias %B 12th International Conference on Quality of Multimedia Experience (QoMEX) %C Athlone, Ireland %D 2020 %T Don’t Stop the Music: Crowdsourced QoE Assessment of Music Streaming with Stalling %X Streaming made a lasting effect on the way our society consumes media in the last decade. While due to streaming the way we listen to music and podcasts has changed drastically, there are very few studies about its Quality of Experience (QoE) and possible influence factors. From video QoE studies, we know that, for example, undesirable stops of the stream (stalling events) have a significant impact on QoE. However, the way in which music and video streaming is consumed differs significantly, as music is often played in the background, and thus, the influence of stalling could be significantly different. Thus, this work evaluates the impact of stalling on music streaming QoE. Therefore, we conduct two crowdsourced user studies: In the first study, users have to rate four songs with different stalling patterns and evaluate the degree of impairments. Afterwards, we compare the ratings to the results of a lab study and show that they are highly correlated, and that crowdsourcing is a suitable way of measuring music streaming QoE. In addition, we conduct a second crowdsourcing study to investigate the influence of the user's attentiveness on QoE. Here, participants have to listen to one song with two stalling events, while one half of them had to transcribe a handwritten text with music playing in the background. The attentiveness shows no influence on the perceived streaming quality, but it shows a significant influence on the perceived quality degradation due to stalling events. Furthermore, considerably more stalling events were missed for workers who focused on the transcription. These results are an important step towards establishing new methods for investigating QoE in multimedia.
• Studying the Impact of the Content Selection Method on the Video QoE on Mobile Devices. Wehner, Nikolas; Mertinat, Nils; Seufert, Michael; Hoßfeld, Tobias. In 12th International Conference on Quality of Multimedia Experience (QoMEX). Athlone, Ireland, 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  When conducting video QoE studies, participants are usually asked to rate the QoE of prepared test videos. However, participants are given no choice to select content, which they like or in which they are interested. This may cause annoyance or frustration when conducting the QoE study, which eventually might affect the QoE results of the study. The consequent question is whether the content liking has a direct impact on the submitted ratings by the participants and whether the freedom of choosing the video content in QoE studies results in better ratings. To investigate this research question, MCA, an existing framework for crowdsourced video testing, is extended and used in a pilot field study. MCA runs on mobile devices and allows users to watch the tested conditions of a QoE study within video content of their interest. The results of a QoE study with individual and dynamic content selection are compared to a QoE study with pre-selected contents. Moreover, this work includes a comparison to a previous QoE study for validation. As the previous study was conducted on desktop PCs, the MCA study further allows to identify differences in the stalling perception between studies on desktop PCs and mobile devices.

  @inproceedings{info3-inproceedings-2020-8, abstract = {When conducting video QoE studies, participants are usually asked to rate the QoE of prepared test videos. However, participants are given no choice to select content, which they like or in which they are interested. This may cause annoyance or frustration when conducting the QoE study, which eventually might affect the QoE results of the study. The consequent question is whether the content liking has a direct impact on the submitted ratings by the participants and whether the freedom of choosing the video content in QoE studies results in better ratings. To investigate this research question, MCA, an existing framework for crowdsourced video testing, is extended and used in a pilot field study. MCA runs on mobile devices and allows users to watch the tested conditions of a QoE study within video content of their interest. The results of a QoE study with individual and dynamic content selection are compared to a QoE study with pre-selected contents. Moreover, this work includes a comparison to a previous QoE study for validation. As the previous study was conducted on desktop PCs, the MCA study further allows to identify differences in the stalling perception between studies on desktop PCs and mobile devices.}, address = {Athlone, Ireland}, author = {Wehner, Nikolas and Mertinat, Nils and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {12th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ucn}, month = {05}, title = {Studying the Impact of the Content Selection Method on the Video QoE on Mobile Devices}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-8 %A Wehner, Nikolas %A Mertinat, Nils %A Seufert, Michael %A Hoßfeld, Tobias %B 12th International Conference on Quality of Multimedia Experience (QoMEX) %C Athlone, Ireland %D 2020 %T Studying the Impact of the Content Selection Method on the Video QoE on Mobile Devices %X When conducting video QoE studies, participants are usually asked to rate the QoE of prepared test videos. However, participants are given no choice to select content, which they like or in which they are interested. This may cause annoyance or frustration when conducting the QoE study, which eventually might affect the QoE results of the study. The consequent question is whether the content liking has a direct impact on the submitted ratings by the participants and whether the freedom of choosing the video content in QoE studies results in better ratings. To investigate this research question, MCA, an existing framework for crowdsourced video testing, is extended and used in a pilot field study. MCA runs on mobile devices and allows users to watch the tested conditions of a QoE study within video content of their interest. The results of a QoE study with individual and dynamic content selection are compared to a QoE study with pre-selected contents. Moreover, this work includes a comparison to a previous QoE study for validation. As the previous study was conducted on desktop PCs, the MCA study further allows to identify differences in the stalling perception between studies on desktop PCs and mobile devices.
• Different Points of View: Impact of 3D Point Cloud Reduction on QoE of Rendered Images. Seufert, Michael; Kargl, Julian; Schauer, Johannes; Nüchter, Andreas; Hoßfeld, Tobias. In 12th International Conference on Quality of Multimedia Experience (QoMEX). Athlone, Ireland, 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Modern photogrammetric methods as well as laser measurement systems make it easy to collect large 3D point clouds that sample objects or environments. As the recorded point clouds can be used to render computer-generated images and models, they are of particular interest in the domains of geographical and architectural engineering, as well for computer graphics (e.g., games or virtual reality). However, point clouds have a huge storage demand, thus, point clouds shall be reduced by removing some of the points. This will inevitably also reduce the Quality of Experience (QoE) of media, which is rendered from the reduced point clouds. In this work, the impact of two different reduction methods on the QoE of rendered images is investigated from two point of views, i.e., based on ratings from both naive crowdworkers as well as point cloud experts.

  @inproceedings{info3-inproceedings-2020-4, abstract = {Modern photogrammetric methods as well as laser measurement systems make it easy to collect large 3D point clouds that sample objects or environments. As the recorded point clouds can be used to render computer-generated images and models, they are of particular interest in the domains of geographical and architectural engineering, as well for computer graphics (e.g., games or virtual reality). However, point clouds have a huge storage demand, thus, point clouds shall be reduced by removing some of the points. This will inevitably also reduce the Quality of Experience (QoE) of media, which is rendered from the reduced point clouds. In this work, the impact of two different reduction methods on the QoE of rendered images is investigated from two point of views, i.e., based on ratings from both naive crowdworkers as well as point cloud experts.}, address = {Athlone, Ireland}, author = {Seufert, Michael and Kargl, Julian and Schauer, Johannes and Nüchter, Andreas and Hoßfeld, Tobias}, booktitle = {12th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ua-net}, month = {05}, title = {Different Points of View: Impact of 3D Point Cloud Reduction on QoE of Rendered Images}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-4 %A Seufert, Michael %A Kargl, Julian %A Schauer, Johannes %A Nüchter, Andreas %A Hoßfeld, Tobias %B 12th International Conference on Quality of Multimedia Experience (QoMEX) %C Athlone, Ireland %D 2020 %T Different Points of View: Impact of 3D Point Cloud Reduction on QoE of Rendered Images %X Modern photogrammetric methods as well as laser measurement systems make it easy to collect large 3D point clouds that sample objects or environments. As the recorded point clouds can be used to render computer-generated images and models, they are of particular interest in the domains of geographical and architectural engineering, as well for computer graphics (e.g., games or virtual reality). However, point clouds have a huge storage demand, thus, point clouds shall be reduced by removing some of the points. This will inevitably also reduce the Quality of Experience (QoE) of media, which is rendered from the reduced point clouds. In this work, the impact of two different reduction methods on the QoE of rendered images is investigated from two point of views, i.e., based on ratings from both naive crowdworkers as well as point cloud experts.
• QoE Assessment of Enterprise Applications based on Self-motivated Ratings. Borchert, Kathrin; Seufert, Michael; Hildebrand, Kathrin; Hoßfeld, Tobias. In 12th International Conference on Quality of Multimedia Experience (QoMEX). Athlone, Ireland, 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  In most companies, enterprise applications, such as office products or databases, are heavily used by employees during work hours. Impairments and performance issues not only slow down business processes, but might also increase the frustration of the workforce. While Quality of Experience (QoE) has been widely studied for personal multimedia applications, such as video streaming, its application to the business usage domain is still in its infancy. Due to several reasons, e.g., the high complexity of IT infrastructure, classical QoE studies can hardly be transferred to business applications. These studies are often independent from the context of usage and actively poll ratings from their participants. This work contrasts the commonly used "pull" method for collecting user ratings with a self-motivated "push" approach. This approach is inspired by complaint systems, in which users can directly report problems with a technical system as soon as they notice them. Therefore, performance assessments of a business application from employees of a cooperating company are collected with both rating systems during a time span of 1.5 years. Besides the analysis of the interaction of users with the "push" system, differences between the two methods are discussed. Further, QoE models for the monitored business application are derived based on the self-motivated "push" ratings.

  @inproceedings{info3-inproceedings-2020-3, abstract = {In most companies, enterprise applications, such as office products or databases, are heavily used by employees during work hours. Impairments and performance issues not only slow down business processes, but might also increase the frustration of the workforce. While Quality of Experience (QoE) has been widely studied for personal multimedia applications, such as video streaming, its application to the business usage domain is still in its infancy. Due to several reasons, e.g., the high complexity of IT infrastructure, classical QoE studies can hardly be transferred to business applications. These studies are often independent from the context of usage and actively poll ratings from their participants. This work contrasts the commonly used "pull" method for collecting user ratings with a self-motivated "push" approach. This approach is inspired by complaint systems, in which users can directly report problems with a technical system as soon as they notice them. Therefore, performance assessments of a business application from employees of a cooperating company are collected with both rating systems during a time span of 1.5 years. Besides the analysis of the interaction of users with the "push" system, differences between the two methods are discussed. Further, QoE models for the monitored business application are derived based on the self-motivated "push" ratings.}, address = {Athlone, Ireland}, author = {Borchert, Kathrin and Seufert, Michael and Hildebrand, Kathrin and Hoßfeld, Tobias}, booktitle = {12th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {kubus}, month = {05}, title = {QoE Assessment of Enterprise Applications based on Self-motivated Ratings}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-3 %A Borchert, Kathrin %A Seufert, Michael %A Hildebrand, Kathrin %A Hoßfeld, Tobias %B 12th International Conference on Quality of Multimedia Experience (QoMEX) %C Athlone, Ireland %D 2020 %T QoE Assessment of Enterprise Applications based on Self-motivated Ratings %X In most companies, enterprise applications, such as office products or databases, are heavily used by employees during work hours. Impairments and performance issues not only slow down business processes, but might also increase the frustration of the workforce. While Quality of Experience (QoE) has been widely studied for personal multimedia applications, such as video streaming, its application to the business usage domain is still in its infancy. Due to several reasons, e.g., the high complexity of IT infrastructure, classical QoE studies can hardly be transferred to business applications. These studies are often independent from the context of usage and actively poll ratings from their participants. This work contrasts the commonly used "pull" method for collecting user ratings with a self-motivated "push" approach. This approach is inspired by complaint systems, in which users can directly report problems with a technical system as soon as they notice them. Therefore, performance assessments of a business application from employees of a cooperating company are collected with both rating systems during a time span of 1.5 years. Besides the analysis of the interaction of users with the "push" system, differences between the two methods are discussed. Further, QoE models for the monitored business application are derived based on the self-motivated "push" ratings.
• Poster: Per-Hop Bridge-Local Latency Bounds with Strict Priority Transmission Selection. Grigorjew, Alexej; Metzger, Florian; Hoßfeld, Tobias; Specht, Johannes; Götz, Franz-Josef; Chen, Feng; Schmitt, Jürgen. In IFIP Networking Conference. 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  This work presents a proven per-hop latency bound for real-time networks with admission control that does not rely on shaping or timed gates. It can be applied in a distributed control plane using only bridge-local information, making it an ideal candidate for brownfield real-time network installations. A brief comparison with Asynchronous Traffic Shaping (ATS) shows that the achieved network utilization is comparable to that of ATS in some scenarios, while it only lags behind in scenarios with accumulating bursts where re-shaping could actually reduce the interference of the observed streams.

  @inproceedings{info3-inproceedings-2020-16, abstract = {This work presents a proven per-hop latency bound for real-time networks with admission control that does not rely on shaping or timed gates. It can be applied in a distributed control plane using only bridge-local information, making it an ideal candidate for brownfield real-time network installations. A brief comparison with Asynchronous Traffic Shaping (ATS) shows that the achieved network utilization is comparable to that of ATS in some scenarios, while it only lags behind in scenarios with accumulating bursts where re-shaping could actually reduce the interference of the observed streams.}, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes and Götz, Franz-Josef and Chen, Feng and Schmitt, Jürgen}, booktitle = {IFIP Networking Conference}, keywords = {ats-performance}, month = {06}, title = {Poster: Per-Hop Bridge-Local Latency Bounds with Strict Priority Transmission Selection}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-16 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %A Götz, Franz-Josef %A Chen, Feng %A Schmitt, Jürgen %B IFIP Networking Conference %D 2020 %T Poster: Per-Hop Bridge-Local Latency Bounds with Strict Priority Transmission Selection %X This work presents a proven per-hop latency bound for real-time networks with admission control that does not rely on shaping or timed gates. It can be applied in a distributed control plane using only bridge-local information, making it an ideal candidate for brownfield real-time network installations. A brief comparison with Asynchronous Traffic Shaping (ATS) shows that the achieved network utilization is comparable to that of ATS in some scenarios, while it only lags behind in scenarios with accumulating bursts where re-shaping could actually reduce the interference of the observed streams.
• Crowdsourced Network Measurements in Germany: Mobile Internet Experience from End User Perspective. Schwind, Anika; Wamser, Florian; Hoßfeld, Tobias; Wunderer, Stefan; Tarnvik, Erik; Hall, Andy. In Broadband Coverage in Germany; 14. ITG Symposium. Berlin, 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  • [ Download ]
  Collecting and analyzing meaningful data in mobile networks is the key to assessing network performance. Crowdsourced Network Measurements (CNMs) provide insights beyond the network layer and offer performance and other measurements at the application and user-level towards Quality of Experience (QoE). In this paper, the mobile Internet experience for Germany is evaluated with the help of crowdsourcing from the perspective of an end user. We statistically analyze a dataset with throughput measurements on the end device from Tutela Ltd., which covers more than 2.5 million throughput tests across Germany from January to July 2019. We give insights into this emerging methodology and highlight the benefits of this method. The paper contains statistics and conclusions for several large cities as well as regions in Germany compared to general statements for Germany, since individual measurements and averages often only imprecisely reflect the situation. The goal is to give a holistic view of the performance of the current mobile network in Germany. Reading this paper, it becomes evident that reliable statements about the quality of the mobile network for Germany depend on a large number of peculiarities in different regions with their own performance characteristics due to different network deployments and population numbers.

  @inproceedings{info3-inproceedings-2020-13, abstract = {Collecting and analyzing meaningful data in mobile networks is the key to assessing network performance. Crowdsourced Network Measurements (CNMs) provide insights beyond the network layer and offer performance and other measurements at the application and user-level towards Quality of Experience (QoE). In this paper, the mobile Internet experience for Germany is evaluated with the help of crowdsourcing from the perspective of an end user. We statistically analyze a dataset with throughput measurements on the end device from Tutela Ltd., which covers more than 2.5 million throughput tests across Germany from January to July 2019. We give insights into this emerging methodology and highlight the benefits of this method. The paper contains statistics and conclusions for several large cities as well as regions in Germany compared to general statements for Germany, since individual measurements and averages often only imprecisely reflect the situation. The goal is to give a holistic view of the performance of the current mobile network in Germany. Reading this paper, it becomes evident that reliable statements about the quality of the mobile network for Germany depend on a large number of peculiarities in different regions with their own performance characteristics due to different network deployments and population numbers.}, address = {Berlin}, author = {Schwind, Anika and Wamser, Florian and Hoßfeld, Tobias and Wunderer, Stefan and Tarnvik, Erik and Hall, Andy}, booktitle = {Broadband Coverage in Germany; 14. ITG Symposium}, keywords = {can}, month = {08}, title = {Crowdsourced Network Measurements in Germany: Mobile Internet Experience from End User Perspective}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-13 %A Schwind, Anika %A Wamser, Florian %A Hoßfeld, Tobias %A Wunderer, Stefan %A Tarnvik, Erik %A Hall, Andy %B Broadband Coverage in Germany; 14. ITG Symposium %C Berlin %D 2020 %T Crowdsourced Network Measurements in Germany: Mobile Internet Experience from End User Perspective %X Collecting and analyzing meaningful data in mobile networks is the key to assessing network performance. Crowdsourced Network Measurements (CNMs) provide insights beyond the network layer and offer performance and other measurements at the application and user-level towards Quality of Experience (QoE). In this paper, the mobile Internet experience for Germany is evaluated with the help of crowdsourcing from the perspective of an end user. We statistically analyze a dataset with throughput measurements on the end device from Tutela Ltd., which covers more than 2.5 million throughput tests across Germany from January to July 2019. We give insights into this emerging methodology and highlight the benefits of this method. The paper contains statistics and conclusions for several large cities as well as regions in Germany compared to general statements for Germany, since individual measurements and averages often only imprecisely reflect the situation. The goal is to give a holistic view of the performance of the current mobile network in Germany. Reading this paper, it becomes evident that reliable statements about the quality of the mobile network for Germany depend on a large number of peculiarities in different regions with their own performance characteristics due to different network deployments and population numbers.
• Scoring High: Analysis and Prediction of Viewer Behavior and Engagement in the Context of 2018 FIFA WC Live Streaming. Wehner, Nikolas; Seufert, Michael; Egger-Lampl, Sebastian; Gardlo, Bruno; Casas, Pedro; Schatz, Raimund. In Proceedings of the 28th ACM International Conference on Multimedia (MM). Seattle, WA, USA, 2020.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2020-9, address = {Seattle, WA, USA}, author = {Wehner, Nikolas and Seufert, Michael and Egger-Lampl, Sebastian and Gardlo, Bruno and Casas, Pedro and Schatz, Raimund}, booktitle = {Proceedings of the 28th ACM International Conference on Multimedia (MM)}, keywords = {ucn}, month = 10, title = {Scoring High: Analysis and Prediction of Viewer Behavior and Engagement in the Context of 2018 FIFA WC Live Streaming}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-9 %A Wehner, Nikolas %A Seufert, Michael %A Egger-Lampl, Sebastian %A Gardlo, Bruno %A Casas, Pedro %A Schatz, Raimund %B Proceedings of the 28th ACM International Conference on Multimedia (MM) %C Seattle, WA, USA %D 2020 %T Scoring High: Analysis and Prediction of Viewer Behavior and Engagement in the Context of 2018 FIFA WC Live Streaming
• Are you on Mobile or Desktop? On the Impact of End-User Device on Web QoE Inference from Encrypted Traffic. Wassermann, Sarah; Casas, Pedro; Ben Houidi, Zied; Huet, Alexis; Seufert, Michael; Wehner, Nikolas; Schüler, Joshua; Cai, Sheng-Ming; Shi, Hao; Xu, Jinchun; Hoßfeld, Tobias; Rossi, Dario. In 16th International Conference on Network and Service Management (CNSM). Izmir, Turkey, 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Web browsing is one of the key applications of the Internet, if not the most important one. We address the problem of Web Quality of Experience (QoE) monitoring from the ISP perspective, relying on in-network, passive measurements. As a proxy to Web QoE, we focus on the analysis of the well-known SpeedIndex (SI) metric. Given the lack of app-level data visibility introduced by the wide adoption of end-to-end encryption, we resort to machine-learning models to infer the SI and the QoE level of individual web page loading sessions, using as input only packet- and flow-level data. Our study targets the impact of different end-user device types (e.g., smartphone, desktop, tablet) on the performance of such models. Empirical evaluations on a large, multi-device, heterogeneous corpus of Web QoE measurements for top popular websites demonstrate that the proposed solution can infer the SI as well as estimate QoE ranges with high accuracy, using either packet-level or flow-level measurements. In addition, we show that the device type adds a strong bias in the feasibility of these Web QoE models, putting into question the applicability of previously conceived approaches on single-device measurements. To improve the state of affairs, we conceive cross-device generalizable models operating at both packet and flow levels, offering a feasible solution for Web QoE monitoring in operational, multi-device networks. To the best of our knowledge, this is the first study tackling the analysis of Web QoE from encrypted network traffic in multi-device scenarios.

  @inproceedings{info3-inproceedings-2020-10, abstract = {Web browsing is one of the key applications of the Internet, if not the most important one. We address the problem of Web Quality of Experience (QoE) monitoring from the ISP perspective, relying on in-network, passive measurements. As a proxy to Web QoE, we focus on the analysis of the well-known SpeedIndex (SI) metric. Given the lack of app-level data visibility introduced by the wide adoption of end-to-end encryption, we resort to machine-learning models to infer the SI and the QoE level of individual web page loading sessions, using as input only packet- and flow-level data. Our study targets the impact of different end-user device types (e.g., smartphone, desktop, tablet) on the performance of such models. Empirical evaluations on a large, multi-device, heterogeneous corpus of Web QoE measurements for top popular websites demonstrate that the proposed solution can infer the SI as well as estimate QoE ranges with high accuracy, using either packet-level or flow-level measurements. In addition, we show that the device type adds a strong bias in the feasibility of these Web QoE models, putting into question the applicability of previously conceived approaches on single-device measurements. To improve the state of affairs, we conceive cross-device generalizable models operating at both packet and flow levels, offering a feasible solution for Web QoE monitoring in operational, multi-device networks. To the best of our knowledge, this is the first study tackling the analysis of Web QoE from encrypted network traffic in multi-device scenarios.}, address = {Izmir, Turkey}, author = {Wassermann, Sarah and Casas, Pedro and Ben Houidi, Zied and Huet, Alexis and Seufert, Michael and Wehner, Nikolas and Schüler, Joshua and Cai, Sheng-Ming and Shi, Hao and Xu, Jinchun and Hoßfeld, Tobias and Rossi, Dario}, booktitle = {16th International Conference on Network and Service Management (CNSM)}, keywords = {ucn}, month = 11, title = {Are you on Mobile or Desktop? On the Impact of End-User Device on Web QoE Inference from Encrypted Traffic}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-10 %A Wassermann, Sarah %A Casas, Pedro %A Ben Houidi, Zied %A Huet, Alexis %A Seufert, Michael %A Wehner, Nikolas %A Schüler, Joshua %A Cai, Sheng-Ming %A Shi, Hao %A Xu, Jinchun %A Hoßfeld, Tobias %A Rossi, Dario %B 16th International Conference on Network and Service Management (CNSM) %C Izmir, Turkey %D 2020 %T Are you on Mobile or Desktop? On the Impact of End-User Device on Web QoE Inference from Encrypted Traffic %X Web browsing is one of the key applications of the Internet, if not the most important one. We address the problem of Web Quality of Experience (QoE) monitoring from the ISP perspective, relying on in-network, passive measurements. As a proxy to Web QoE, we focus on the analysis of the well-known SpeedIndex (SI) metric. Given the lack of app-level data visibility introduced by the wide adoption of end-to-end encryption, we resort to machine-learning models to infer the SI and the QoE level of individual web page loading sessions, using as input only packet- and flow-level data. Our study targets the impact of different end-user device types (e.g., smartphone, desktop, tablet) on the performance of such models. Empirical evaluations on a large, multi-device, heterogeneous corpus of Web QoE measurements for top popular websites demonstrate that the proposed solution can infer the SI as well as estimate QoE ranges with high accuracy, using either packet-level or flow-level measurements. In addition, we show that the device type adds a strong bias in the feasibility of these Web QoE models, putting into question the applicability of previously conceived approaches on single-device measurements. To improve the state of affairs, we conceive cross-device generalizable models operating at both packet and flow levels, offering a feasible solution for Web QoE monitoring in operational, multi-device networks. To the best of our knowledge, this is the first study tackling the analysis of Web QoE from encrypted network traffic in multi-device scenarios.
• Bounded Latency with Bridge-Local Stream Reservation and Strict Priority Queuing. Grigorjew, Alexej; Metzger, Florian; Hoßfeld, Tobias; Specht, Johannes; Götz, Franz-Josef; Chen, Feng; Schmitt, Jürgen. In 11th International Conference on Network of the Future (NoF). 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Bridge-local latency computation is often regarded with caution, while new shaping mechanisms and timed gates are developed to achieve deterministic guarantees. However, these new concepts require additional hardware support in the forwarding devices, and many of them are based on assumptions of central control and network-wide information being available. This document presents a per-hop latency bound for individual streams in a class-based network that applies the IEEE 802.1Q strict priority transmission selection algorithm. It does not rely on shaping or timed gates and uses the accumulated latency fields during the reservation process to provide upper bounds with bridge-local information. The presented delay bound is proven formally and then evaluated with respect to its accuracy. It shows that deterministic latency with priority queuing is indeed feasible, and it indicates the required information that must be provided during resource reservation, e.g., to protocols developed in IEEE 802.1Qdd.

  @inproceedings{info3-inproceedings-2020-17, abstract = {Bridge-local latency computation is often regarded with caution, while new shaping mechanisms and timed gates are developed to achieve deterministic guarantees. However, these new concepts require additional hardware support in the forwarding devices, and many of them are based on assumptions of central control and network-wide information being available. This document presents a per-hop latency bound for individual streams in a class-based network that applies the IEEE 802.1Q strict priority transmission selection algorithm. It does not rely on shaping or timed gates and uses the accumulated latency fields during the reservation process to provide upper bounds with bridge-local information. The presented delay bound is proven formally and then evaluated with respect to its accuracy. It shows that deterministic latency with priority queuing is indeed feasible, and it indicates the required information that must be provided during resource reservation, e.g., to protocols developed in IEEE 802.1Qdd.}, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes and Götz, Franz-Josef and Chen, Feng and Schmitt, Jürgen}, booktitle = {11th International Conference on Network of the Future (NoF)}, keywords = {ats-performance}, month = 11, title = {Bounded Latency with Bridge-Local Stream Reservation and Strict Priority Queuing}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-17 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %A Götz, Franz-Josef %A Chen, Feng %A Schmitt, Jürgen %B 11th International Conference on Network of the Future (NoF) %D 2020 %T Bounded Latency with Bridge-Local Stream Reservation and Strict Priority Queuing %X Bridge-local latency computation is often regarded with caution, while new shaping mechanisms and timed gates are developed to achieve deterministic guarantees. However, these new concepts require additional hardware support in the forwarding devices, and many of them are based on assumptions of central control and network-wide information being available. This document presents a per-hop latency bound for individual streams in a class-based network that applies the IEEE 802.1Q strict priority transmission selection algorithm. It does not rely on shaping or timed gates and uses the accumulated latency fields during the reservation process to provide upper bounds with bridge-local information. The presented delay bound is proven formally and then evaluated with respect to its accuracy. It shows that deterministic latency with priority queuing is indeed feasible, and it indicates the required information that must be provided during resource reservation, e.g., to protocols developed in IEEE 802.1Qdd.
• Mind the (QoE) Gap: On the Incompatibility of Web and Video QoE Models in the Wild. Seufert, Michael; Wehner, Nikolas; Wieser, Viktoria; Casas, Pedro; Capdehourat, Germán. In 16th International Conference on Network and Service Management (CNSM). Izmir, Turkey, 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Education Service Providers (ESPs) have a paramount role in the digitization of education, providing reliable devices for students and teachers and high quality Internet access at schools. In this paper, a large-scale, passive, in-device Quality of Experience (QoE) monitoring system is presented, which was deployed into a nationwide network of education-purpose devices. Four months' worth of continuous measurements were conducted by an ESP, covering more than 800 education centers and about 4000 devices, used both in schools and at home. When analyzing the QoE of web sessions in school networks, we identify a fundamental issue with the compatibility of web browsing and video QoE models, which inhibits the successful application of QoE-aware network management for multiple services.

  @inproceedings{info3-inproceedings-2020-11, abstract = {Education Service Providers (ESPs) have a paramount role in the digitization of education, providing reliable devices for students and teachers and high quality Internet access at schools. In this paper, a large-scale, passive, in-device Quality of Experience (QoE) monitoring system is presented, which was deployed into a nationwide network of education-purpose devices. Four months' worth of continuous measurements were conducted by an ESP, covering more than 800 education centers and about 4000 devices, used both in schools and at home. When analyzing the QoE of web sessions in school networks, we identify a fundamental issue with the compatibility of web browsing and video QoE models, which inhibits the successful application of QoE-aware network management for multiple services.}, address = {Izmir, Turkey}, author = {Seufert, Michael and Wehner, Nikolas and Wieser, Viktoria and Casas, Pedro and Capdehourat, Germán}, booktitle = {16th International Conference on Network and Service Management (CNSM)}, keywords = {ucn}, month = 11, title = {Mind the (QoE) Gap: On the Incompatibility of Web and Video QoE Models in the Wild}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-11 %A Seufert, Michael %A Wehner, Nikolas %A Wieser, Viktoria %A Casas, Pedro %A Capdehourat, Germán %B 16th International Conference on Network and Service Management (CNSM) %C Izmir, Turkey %D 2020 %T Mind the (QoE) Gap: On the Incompatibility of Web and Video QoE Models in the Wild %X Education Service Providers (ESPs) have a paramount role in the digitization of education, providing reliable devices for students and teachers and high quality Internet access at schools. In this paper, a large-scale, passive, in-device Quality of Experience (QoE) monitoring system is presented, which was deployed into a nationwide network of education-purpose devices. Four months' worth of continuous measurements were conducted by an ESP, covering more than 800 education centers and about 4000 devices, used both in schools and at home. When analyzing the QoE of web sessions in school networks, we identify a fundamental issue with the compatibility of web browsing and video QoE models, which inhibits the successful application of QoE-aware network management for multiple services.
• Improving Web QoE Monitoring for Encrypted Network Traffic through Time Series Modeling. Wehner, Nikolas; Seufert, Michael; Schüler, Joshua; Wassermann, Sarah; Casas, Pedro; Hoßfeld, Tobias. In 2nd Workshop on AI in Networks and Distributed Systems (WAIN). Milan, Italy, 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  This paper addresses the problem of Quality of Experience (QoE) monitoring for web browsing. In particular, the inference of common Web QoE metrics such as Speed Index (SI) is investigated. Based on a large dataset collected with open web-measurement platforms on different device-types, a unique feature set is designed and used to estimate the RUMSI -- an efficient approximation to SI, with machine-learning based regression and classification approaches. Results indicate that it is possible to estimate the RUMSI accurately, and that in particular, recurrent neural networks are highly suitable for the task, as they capture the network dynamics more precisely.

  @inproceedings{info3-inproceedings-2020-12, abstract = {This paper addresses the problem of Quality of Experience (QoE) monitoring for web browsing. In particular, the inference of common Web QoE metrics such as Speed Index (SI) is investigated. Based on a large dataset collected with open web-measurement platforms on different device-types, a unique feature set is designed and used to estimate the RUMSI – an efficient approximation to SI, with machine-learning based regression and classification approaches. Results indicate that it is possible to estimate the RUMSI accurately, and that in particular, recurrent neural networks are highly suitable for the task, as they capture the network dynamics more precisely.}, address = {Milan, Italy}, author = {Wehner, Nikolas and Seufert, Michael and Schüler, Joshua and Wassermann, Sarah and Casas, Pedro and Hoßfeld, Tobias}, booktitle = {2nd Workshop on AI in Networks and Distributed Systems (WAIN)}, keywords = {ucn}, month = 11, title = {Improving Web QoE Monitoring for Encrypted Network Traffic through Time Series Modeling}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-12 %A Wehner, Nikolas %A Seufert, Michael %A Schüler, Joshua %A Wassermann, Sarah %A Casas, Pedro %A Hoßfeld, Tobias %B 2nd Workshop on AI in Networks and Distributed Systems (WAIN) %C Milan, Italy %D 2020 %T Improving Web QoE Monitoring for Encrypted Network Traffic through Time Series Modeling %X This paper addresses the problem of Quality of Experience (QoE) monitoring for web browsing. In particular, the inference of common Web QoE metrics such as Speed Index (SI) is investigated. Based on a large dataset collected with open web-measurement platforms on different device-types, a unique feature set is designed and used to estimate the RUMSI -- an efficient approximation to SI, with machine-learning based regression and classification approaches. Results indicate that it is possible to estimate the RUMSI accurately, and that in particular, recurrent neural networks are highly suitable for the task, as they capture the network dynamics more precisely.
• From QoS Distributions to QoE Distributions: a System’s Perspective. Hoßfeld, Tobias; Heegaard, Poul E.; Varela, Martin; Skorin-Kapov, Lea; Fiedler, Markus. In 4th International Workshop on Quality of Experience Management (QoE Management 2020), featured by IEEE Conference on Network Softwarization (IEEE NetSoft 2020). Ghent, Belgium, 2020.
  • [ Abstract ]
  • [ BibTeX ]
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  • [ Download ]
  In the context of QoE management, network and service providers commonly rely on models that map system QoS conditions (e.g., system response time, packet loss, etc.) to estimated end user QoE values. Observable QoS conditions in the system may be assumed to follow a certain distribution, meaning that different end users will experience different conditions. On the other hand, drawing from the results of subjective user studies, we know that user diversity leads to distributions of user scores for any given test conditions (in this case referring to the QoS parameters of interest). Our previous studies have shown that to correctly derive various QoE metrics (e.g., Mean Opinion Score (MOS), quantiles, probability of users rating 'good or better', etc.) in a system under given conditions, there is a need to consider rating distributions obtained from user studies, which are often times not available. In the paper we extend these findings to show how to approximate user rating distributions given a QoS-to-MOS mapping function and second order statistics. Such a user rating distribution may then be combined with a QoS distribution observed in a system to finally derive corresponding distributions of QoE scores. Scripts are provided for the approximating a QoE distribution with a Beta distribution for given MOS and SOS parameter at https://github.com/hossfeld/approx-qoe-distribution.

  @inproceedings{info3-inproceedings-2020-6, abstract = {In the context of QoE management, network and service providers commonly rely on models that map system QoS conditions (e.g., system response time, packet loss, etc.) to estimated end user QoE values. Observable QoS conditions in the system may be assumed to follow a certain distribution, meaning that different end users will experience different conditions. On the other hand, drawing from the results of subjective user studies, we know that user diversity leads to distributions of user scores for any given test conditions (in this case referring to the QoS parameters of interest). Our previous studies have shown that to correctly derive various QoE metrics (e.g., Mean Opinion Score (MOS), quantiles, probability of users rating 'good or better', etc.) in a system under given conditions, there is a need to consider rating distributions obtained from user studies, which are often times not available. In the paper we extend these findings to show how to approximate user rating distributions given a QoS-to-MOS mapping function and second order statistics. Such a user rating distribution may then be combined with a QoS distribution observed in a system to finally derive corresponding distributions of QoE scores. Scripts are provided for the approximating a QoE distribution with a Beta distribution for given MOS and SOS parameter at https://github.com/hossfeld/approx-qoe-distribution.}, address = {Ghent, Belgium}, author = {Hoßfeld, Tobias and Heegaard, Poul E. and Varela, Martin and Skorin-Kapov, Lea and Fiedler, Markus}, booktitle = {4th International Workshop on Quality of Experience Management (QoE Management 2020), featured by IEEE Conference on Network Softwarization (IEEE NetSoft 2020)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {From QoS Distributions to QoE Distributions: a System's Perspective}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-6 %A Hoßfeld, Tobias %A Heegaard, Poul E. %A Varela, Martin %A Skorin-Kapov, Lea %A Fiedler, Markus %B 4th International Workshop on Quality of Experience Management (QoE Management 2020), featured by IEEE Conference on Network Softwarization (IEEE NetSoft 2020) %C Ghent, Belgium %D 2020 %T From QoS Distributions to QoE Distributions: a System's Perspective %X In the context of QoE management, network and service providers commonly rely on models that map system QoS conditions (e.g., system response time, packet loss, etc.) to estimated end user QoE values. Observable QoS conditions in the system may be assumed to follow a certain distribution, meaning that different end users will experience different conditions. On the other hand, drawing from the results of subjective user studies, we know that user diversity leads to distributions of user scores for any given test conditions (in this case referring to the QoS parameters of interest). Our previous studies have shown that to correctly derive various QoE metrics (e.g., Mean Opinion Score (MOS), quantiles, probability of users rating 'good or better', etc.) in a system under given conditions, there is a need to consider rating distributions obtained from user studies, which are often times not available. In the paper we extend these findings to show how to approximate user rating distributions given a QoS-to-MOS mapping function and second order statistics. Such a user rating distribution may then be combined with a QoS distribution observed in a system to finally derive corresponding distributions of QoE scores. Scripts are provided for the approximating a QoE distribution with a Beta distribution for given MOS and SOS parameter at https://github.com/hossfeld/approx-qoe-distribution.

• QUICker or not? - an Empirical Analysis of QUIC vs TCP for Video Streaming QoE Provisioning. Seufert, Michael; Schatz, Raimund; Wehner, Nikolas; Casas, Pedro. In 3rd International Workshop on Quality of Experience Management (QoE-Management). Paris, France, 2019.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  The introduction of the QUIC (Quick UDP Internet Connections) transport protocol by Google aimed to improve the Quality of Experience (QoE) with web services compared to the prevailing Transport Control Protocol (TCP). Nowadays, QUIC has become the default protocol to communicate between the Google Chrome browser and Google servers and accounts for an increasing share of the Internet traffic. This work investigates whether the promised QoE benefits of QUIC are indeed noticeable for end users or not. A measurement study was conducted for YouTube video streaming in two mobile and two fixed access networks, in which a defined set of videos was streamed back-to-back with QUIC and TCP in randomized order. QoE factors of video streaming (such as initial delay, the visual quality of the video, and stalling) were compared statistically to find significant differences between the streaming over QUIC and the streaming over TCP. Surprisingly, no evidence for any QoE improvement of QUIC over TCP in the context of YouTube streaming could be found.

  @inproceedings{info3-inproceedings-2019-7, abstract = {The introduction of the QUIC (Quick UDP Internet Connections) transport protocol by Google aimed to improve the Quality of Experience (QoE) with web services compared to the prevailing Transport Control Protocol (TCP). Nowadays, QUIC has become the default protocol to communicate between the Google Chrome browser and Google servers and accounts for an increasing share of the Internet traffic. This work investigates whether the promised QoE benefits of QUIC are indeed noticeable for end users or not. A measurement study was conducted for YouTube video streaming in two mobile and two fixed access networks, in which a defined set of videos was streamed back-to-back with QUIC and TCP in randomized order. QoE factors of video streaming (such as initial delay, the visual quality of the video, and stalling) were compared statistically to find significant differences between the streaming over QUIC and the streaming over TCP. Surprisingly, no evidence for any QoE improvement of QUIC over TCP in the context of YouTube streaming could be found.}, address = {Paris, France}, author = {Seufert, Michael and Schatz, Raimund and Wehner, Nikolas and Casas, Pedro}, booktitle = {3rd International Workshop on Quality of Experience Management (QoE-Management)}, keywords = {ua-net}, month = {02}, title = {QUICker or not? - an Empirical Analysis of QUIC vs TCP for Video Streaming QoE Provisioning}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-7 %A Seufert, Michael %A Schatz, Raimund %A Wehner, Nikolas %A Casas, Pedro %B 3rd International Workshop on Quality of Experience Management (QoE-Management) %C Paris, France %D 2019 %T QUICker or not? - an Empirical Analysis of QUIC vs TCP for Video Streaming QoE Provisioning %X The introduction of the QUIC (Quick UDP Internet Connections) transport protocol by Google aimed to improve the Quality of Experience (QoE) with web services compared to the prevailing Transport Control Protocol (TCP). Nowadays, QUIC has become the default protocol to communicate between the Google Chrome browser and Google servers and accounts for an increasing share of the Internet traffic. This work investigates whether the promised QoE benefits of QUIC are indeed noticeable for end users or not. A measurement study was conducted for YouTube video streaming in two mobile and two fixed access networks, in which a defined set of videos was streamed back-to-back with QUIC and TCP in randomized order. QoE factors of video streaming (such as initial delay, the visual quality of the video, and stalling) were compared statistically to find significant differences between the streaming over QUIC and the streaming over TCP. Surprisingly, no evidence for any QoE improvement of QUIC over TCP in the context of YouTube streaming could be found.
• Gray, Nicholas, et al. "Highlighting the Gap Between Expected and Actual Behavior in P4-enabled Networks. Gray, Nicholas; Grigorjew, Alexej; Hoßfeld, Tobias; Shukla, Apoorv; Zinner, Thomas. In IFIP/IEEE Symposium on Integrated Network and Service Management (IM). 2019.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Modern networks increasingly rely on Software-defined Networking (SDN) and Network Function Virtualization (NFV) to augment their flexibility in high load scenarios. To further enhance the performance, a part of the functionality is often offloaded to forwarding devices, which are used as hardware accelerators and are configured by high level programming languages such as P4. However, hardware vendors use sophisticated technologies to implement these standards, which need to be understood by the programmer to avoid unintended behavior. In this demonstration we highlight the severe consequences of only relying on the network programming language when ignoring the device-specific limitations. We show this by the example of a Denial of Service attack against a P4-enabled SmartNIC. Finally, we discuss possible mitigations to this attack and stress the importance of an overall understanding of the entire system.

  @inproceedings{info3-demo-2019-1, abstract = {Modern networks increasingly rely on Software-defined Networking (SDN) and Network Function Virtualization (NFV) to augment their flexibility in high load scenarios. To further enhance the performance, a part of the functionality is often offloaded to forwarding devices, which are used as hardware accelerators and are configured by high level programming languages such as P4. However, hardware vendors use sophisticated technologies to implement these standards, which need to be understood by the programmer to avoid unintended behavior. In this demonstration we highlight the severe consequences of only relying on the network programming language when ignoring the device-specific limitations. We show this by the example of a Denial of Service attack against a P4-enabled SmartNIC. Finally, we discuss possible mitigations to this attack and stress the importance of an overall understanding of the entire system.}, author = {Gray, Nicholas and Grigorjew, Alexej and Hoßfeld, Tobias and Shukla, Apoorv and Zinner, Thomas}, booktitle = {IFIP/IEEE Symposium on Integrated Network and Service Management (IM)}, keywords = {sardine}, month = {03}, title = {Gray, Nicholas, et al. "Highlighting the Gap Between Expected and Actual Behavior in P4-enabled Networks}, year = 2019 }

  %0 Conference Paper %1 info3-demo-2019-1 %A Gray, Nicholas %A Grigorjew, Alexej %A Hoßfeld, Tobias %A Shukla, Apoorv %A Zinner, Thomas %B IFIP/IEEE Symposium on Integrated Network and Service Management (IM) %D 2019 %T Gray, Nicholas, et al. "Highlighting the Gap Between Expected and Actual Behavior in P4-enabled Networks %X Modern networks increasingly rely on Software-defined Networking (SDN) and Network Function Virtualization (NFV) to augment their flexibility in high load scenarios. To further enhance the performance, a part of the functionality is often offloaded to forwarding devices, which are used as hardware accelerators and are configured by high level programming languages such as P4. However, hardware vendors use sophisticated technologies to implement these standards, which need to be understood by the programmer to avoid unintended behavior. In this demonstration we highlight the severe consequences of only relying on the network programming language when ignoring the device-specific limitations. We show this by the example of a Denial of Service attack against a P4-enabled SmartNIC. Finally, we discuss possible mitigations to this attack and stress the importance of an overall understanding of the entire system.
• Energy-Efficient Adaptation Logic for HTTP Streaming in Mobile Networks. Moldovan, Christian; Wamser, Florian; Hoßfeld, Tobias. In 2019 International Conference on Networked Systems (NetSys). 2019.
  • [ Abstract ]
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  The requirements for video streaming have changed drastically during the past years. In today's Internet, high definition resolutions are considered default for videos, even in mobile settings, and with 4G penetration reaching 90 percent in the US, this no longer poses a big problem. However, while mobile bandwidth has increased, the battery life time of mobile devices has not increased significantly. Furthermore, current data plans are still not large enough to regularly stream movies during the commute. Users still resort to downloading media before travel. In this paper we propose a new HTTP adaptive streaming algorithm that delivers videos in high quality while avoiding stalling events, schedules the download of video segments so that a energy conserving idle state is often reached and keeps the buffer low at points in the video where many viewers abandon the video to save data. While most adaptive streaming algorithms optimize quality and stalling, this is the first attempt to use an adaptive streaming algorithm to reduce energy consumption. Since video streaming providers mostly care about the Quality of Experience when watching videos, energy efficiency is left to the device manufacturers. Therefore, both parties have little incentive to cooperate in this regard. But on the Internet of tomorrow, where most videos are watched on mobile devices, energy efficiency and the Quality of Experience must go hand in hand.

  @inproceedings{info3-inproceedings-2019-9, abstract = {The requirements for video streaming have changed drastically during the past years. In today's Internet, high definition resolutions are considered default for videos, even in mobile settings, and with 4G penetration reaching 90 percent in the US, this no longer poses a big problem. However, while mobile bandwidth has increased, the battery life time of mobile devices has not increased significantly. Furthermore, current data plans are still not large enough to regularly stream movies during the commute. Users still resort to downloading media before travel. In this paper we propose a new HTTP adaptive streaming algorithm that delivers videos in high quality while avoiding stalling events, schedules the download of video segments so that a energy conserving idle state is often reached and keeps the buffer low at points in the video where many viewers abandon the video to save data. While most adaptive streaming algorithms optimize quality and stalling, this is the first attempt to use an adaptive streaming algorithm to reduce energy consumption. Since video streaming providers mostly care about the Quality of Experience when watching videos, energy efficiency is left to the device manufacturers. Therefore, both parties have little incentive to cooperate in this regard. But on the Internet of tomorrow, where most videos are watched on mobile devices, energy efficiency and the Quality of Experience must go hand in hand.}, author = {Moldovan, Christian and Wamser, Florian and Hoßfeld, Tobias}, booktitle = {2019 International Conference on Networked Systems (NetSys)}, keywords = {energy-efficiency}, month = {03}, title = {Energy-Efficient Adaptation Logic for HTTP Streaming in Mobile Networks}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-9 %A Moldovan, Christian %A Wamser, Florian %A Hoßfeld, Tobias %B 2019 International Conference on Networked Systems (NetSys) %D 2019 %T Energy-Efficient Adaptation Logic for HTTP Streaming in Mobile Networks %X The requirements for video streaming have changed drastically during the past years. In today's Internet, high definition resolutions are considered default for videos, even in mobile settings, and with 4G penetration reaching 90 percent in the US, this no longer poses a big problem. However, while mobile bandwidth has increased, the battery life time of mobile devices has not increased significantly. Furthermore, current data plans are still not large enough to regularly stream movies during the commute. Users still resort to downloading media before travel. In this paper we propose a new HTTP adaptive streaming algorithm that delivers videos in high quality while avoiding stalling events, schedules the download of video segments so that a energy conserving idle state is often reached and keeps the buffer low at points in the video where many viewers abandon the video to save data. While most adaptive streaming algorithms optimize quality and stalling, this is the first attempt to use an adaptive streaming algorithm to reduce energy consumption. Since video streaming providers mostly care about the Quality of Experience when watching videos, energy efficiency is left to the device manufacturers. Therefore, both parties have little incentive to cooperate in this regard. But on the Internet of tomorrow, where most videos are watched on mobile devices, energy efficiency and the Quality of Experience must go hand in hand.
• Web Performance Pitfalls. Enghardt, Theresa; Zinner, Thomas; Feldmann, Anja. In Passive and Active Measurement Conference (PAM). 2019.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2019-1, author = {Enghardt, Theresa and Zinner, Thomas and Feldmann, Anja}, booktitle = {Passive and Active Measurement Conference (PAM)}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Web Performance Pitfalls}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-1 %A Enghardt, Theresa %A Zinner, Thomas %A Feldmann, Anja %B Passive and Active Measurement Conference (PAM) %D 2019 %T Web Performance Pitfalls
• KOMon - Kernel-based Online Monitoring of VNF Packet Processing Times. Geissler, Stefan; Lange, Stanislav; Wamser, Florian; Zinner, Thomas; Hoßfeld, Tobias. In 2019 International Conference on Networked Systems (NetSys), Best Paper Award. 2019.
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  @inproceedings{info3-inproceedings-2019-5, author = {Geissler, Stefan and Lange, Stanislav and Wamser, Florian and Zinner, Thomas and Hoßfeld, Tobias}, booktitle = {2019 International Conference on Networked Systems (NetSys), Best Paper Award}, keywords = {sendate}, month = {03}, title = {KOMon - Kernel-based Online Monitoring of VNF Packet Processing Times}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-5 %A Geissler, Stefan %A Lange, Stanislav %A Wamser, Florian %A Zinner, Thomas %A Hoßfeld, Tobias %B 2019 International Conference on Networked Systems (NetSys), Best Paper Award %D 2019 %T KOMon - Kernel-based Online Monitoring of VNF Packet Processing Times
• A Simulation of Asynchronous Traffic Shapers in Switched Ethernet Networks. Grigorjew, Alexej; Metzger, Florian; Hoßfeld, Tobias; Specht, Johannes. In Workshop for Advanced Communication Networks for Industrial Applications. 2019.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  As the requirements of real-time networking in- crease, the IEEE Time-Sensitive Networking (TSN) task group is working on new standards for high bandwidth and low latency Ethernet switching. In particular, the upcoming P802.1Qcr standard features Asynchronous Traffic Shaping (ATS), which is a promising approach for real-time networks with high dynamics and critical safety requirements. Additionally, parallel concepts such as frame preemption can be used to reduce delays even further. This work presents a discrete event simulation framework that can analyze the performance of these concepts. It implements frame preemption and multiple shaping algorithms, while recording latency and queue utilization statistics at the switches. In addition, an evaluation of a linear topology with four switches is performed under high link utilization, which demonstrates the benefit of the above mechanisms compared to regular Ethernet switching.

  @inproceedings{info3-inproceedings-2019-16, abstract = {As the requirements of real-time networking in- crease, the IEEE Time-Sensitive Networking (TSN) task group is working on new standards for high bandwidth and low latency Ethernet switching. In particular, the upcoming P802.1Qcr standard features Asynchronous Traffic Shaping (ATS), which is a promising approach for real-time networks with high dynamics and critical safety requirements. Additionally, parallel concepts such as frame preemption can be used to reduce delays even further. This work presents a discrete event simulation framework that can analyze the performance of these concepts. It implements frame preemption and multiple shaping algorithms, while recording latency and queue utilization statistics at the switches. In addition, an evaluation of a linear topology with four switches is performed under high link utilization, which demonstrates the benefit of the above mechanisms compared to regular Ethernet switching.}, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes}, booktitle = {Workshop for Advanced Communication Networks for Industrial Applications}, keywords = {fullstack}, month = {03}, title = {A Simulation of Asynchronous Traffic Shapers in Switched Ethernet Networks}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-16 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %B Workshop for Advanced Communication Networks for Industrial Applications %D 2019 %T A Simulation of Asynchronous Traffic Shapers in Switched Ethernet Networks %X As the requirements of real-time networking in- crease, the IEEE Time-Sensitive Networking (TSN) task group is working on new standards for high bandwidth and low latency Ethernet switching. In particular, the upcoming P802.1Qcr standard features Asynchronous Traffic Shaping (ATS), which is a promising approach for real-time networks with high dynamics and critical safety requirements. Additionally, parallel concepts such as frame preemption can be used to reduce delays even further. This work presents a discrete event simulation framework that can analyze the performance of these concepts. It implements frame preemption and multiple shaping algorithms, while recording latency and queue utilization statistics at the switches. In addition, an evaluation of a linear topology with four switches is performed under high link utilization, which demonstrates the benefit of the above mechanisms compared to regular Ethernet switching.
• BBGDASH: A Max-Min Bounded Bitrate Guidance for SDN Enabled Adaptive Video Streaming. Alissa, Ali; Bentalab, Abdelhak; Zinner, Thomas; Ghita, Bogdan; Mkwawa, Is-Haka. In 22nd Conference on Innovation in Clouds, Internet and Networks and Workshops (ICIN. 2019.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2019-2, author = {Alissa, Ali and Bentalab, Abdelhak and Zinner, Thomas and Ghita, Bogdan and Mkwawa, Is-Haka}, booktitle = {22nd Conference on Innovation in Clouds, Internet and Networks and Workshops (ICIN}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {BBGDASH: A Max-Min Bounded Bitrate Guidance for SDN Enabled Adaptive Video Streaming}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-2 %A Alissa, Ali %A Bentalab, Abdelhak %A Zinner, Thomas %A Ghita, Bogdan %A Mkwawa, Is-Haka %B 22nd Conference on Innovation in Clouds, Internet and Networks and Workshops (ICIN %D 2019 %T BBGDASH: A Max-Min Bounded Bitrate Guidance for SDN Enabled Adaptive Video Streaming
• Computing QoE-relevant Adaptive Video Streaming Metrics using Discrete-Time Analysis. Schwarzmann, Susanna; Breitbach, Paula; Zinner, Thomas. In Third International Workshop on Quality of Experience Management 2019. 2019.
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  @inproceedings{info3-inproceedings-2019-3, author = {Schwarzmann, Susanna and Breitbach, Paula and Zinner, Thomas}, booktitle = {Third International Workshop on Quality of Experience Management 2019}, keywords = {dfg-sdn}, month = {02}, title = {Computing QoE-relevant Adaptive Video Streaming Metrics using Discrete-Time Analysis}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-3 %A Schwarzmann, Susanna %A Breitbach, Paula %A Zinner, Thomas %B Third International Workshop on Quality of Experience Management 2019 %D 2019 %T Computing QoE-relevant Adaptive Video Streaming Metrics using Discrete-Time Analysis
• Stream-based Machine Learning for Real-time QoE Analysis of Encrypted Video Streaming Traffic. Seufert, Michael; Casas, Pedro; Wehner, Nikolas; Li, Gang; Kuang, Li. In 3rd International Workshop on Quality of Experience Management (QoE-Management). Paris, France, 2019.
  • [ Abstract ]
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  As stalling is the worst Quality of Experience (QoE) degradation of HTTP adaptive video streaming (HAS), this work presents a stream-based machine learning approach, ViCrypt, which analyzes stalling of YouTube streaming sessions in real-time from encrypted network traffic. The video streaming session is subdivided into a stream of short time slots of 1 s length, while considering two additional macro windows each for the current streaming trend and the whole ongoing streaming session. Constant memory features are extracted from the encrypted network traffic in these three windows in a stream-based fashion, and fed into a random forest model, which predicts whether the current time slot contains stalling or not. The presented system can predict stalling with a very high accuracy and the finest granularity to date (1 s), and thus, can be used in networks for real-time QoE analysis from encrypted YouTube video streaming traffic. The independent predictions for each consecutive slot of a streaming session can further be aggregated to obtain stalling estimations for the whole session. Thereby, the proposed method allows to quantify the initial delay, as well as the overall number of stalling events and the stalling ratio, i.e., the ratio of total stalling time and total playback time.

  @inproceedings{info3-inproceedings-2019-8, abstract = {As stalling is the worst Quality of Experience (QoE) degradation of HTTP adaptive video streaming (HAS), this work presents a stream-based machine learning approach, ViCrypt, which analyzes stalling of YouTube streaming sessions in real-time from encrypted network traffic. The video streaming session is subdivided into a stream of short time slots of 1 s length, while considering two additional macro windows each for the current streaming trend and the whole ongoing streaming session. Constant memory features are extracted from the encrypted network traffic in these three windows in a stream-based fashion, and fed into a random forest model, which predicts whether the current time slot contains stalling or not. The presented system can predict stalling with a very high accuracy and the finest granularity to date (1 s), and thus, can be used in networks for real-time QoE analysis from encrypted YouTube video streaming traffic. The independent predictions for each consecutive slot of a streaming session can further be aggregated to obtain stalling estimations for the whole session. Thereby, the proposed method allows to quantify the initial delay, as well as the overall number of stalling events and the stalling ratio, i.e., the ratio of total stalling time and total playback time.}, address = {Paris, France}, author = {Seufert, Michael and Casas, Pedro and Wehner, Nikolas and Li, Gang and Kuang, Li}, booktitle = {3rd International Workshop on Quality of Experience Management (QoE-Management)}, keywords = {net-man}, month = {02}, title = {Stream-based Machine Learning for Real-time QoE Analysis of Encrypted Video Streaming Traffic}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-8 %A Seufert, Michael %A Casas, Pedro %A Wehner, Nikolas %A Li, Gang %A Kuang, Li %B 3rd International Workshop on Quality of Experience Management (QoE-Management) %C Paris, France %D 2019 %T Stream-based Machine Learning for Real-time QoE Analysis of Encrypted Video Streaming Traffic %X As stalling is the worst Quality of Experience (QoE) degradation of HTTP adaptive video streaming (HAS), this work presents a stream-based machine learning approach, ViCrypt, which analyzes stalling of YouTube streaming sessions in real-time from encrypted network traffic. The video streaming session is subdivided into a stream of short time slots of 1 s length, while considering two additional macro windows each for the current streaming trend and the whole ongoing streaming session. Constant memory features are extracted from the encrypted network traffic in these three windows in a stream-based fashion, and fed into a random forest model, which predicts whether the current time slot contains stalling or not. The presented system can predict stalling with a very high accuracy and the finest granularity to date (1 s), and thus, can be used in networks for real-time QoE analysis from encrypted YouTube video streaming traffic. The independent predictions for each consecutive slot of a streaming session can further be aggregated to obtain stalling estimations for the whole session. Thereby, the proposed method allows to quantify the initial delay, as well as the overall number of stalling events and the stalling ratio, i.e., the ratio of total stalling time and total playback time.
• Peeking under the Hood – How the Measurement Setup Influences the Video Streaming Behavior. Schwind, Anika; Janiak, Lea; Moldovan, Christian; Wamser, Florian; Hoßfeld, Tobias. In The 3rd International Workshop on Quality of Experience Management (QoE-Management 2019). Paris, France, 2019.
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  Global Internet video traffic will dramatically increase in the next years. With this rapid growth, interest in the application behavior of video streaming services and the resulting user experience rises. In particular, there is a need to understand the influence of system parameters on the streaming performance. Thus, several monitoring approaches have been developed which allow conducting automated measurements on a large-scale, for example, lightweight approaches for measurements running in the mobile networks or setups using a virtual frame buffer for servers without a display running in virtualized cloud environments. In some cases, the measurement hardware can totally be controlled, in other cases, there is no knowledge about parallel running services. In this paper, we answer the question whether and how much the measurement setup (e.g., virtualization, headless browsers, load on machines) influences the video streaming behavior. Therefore, we compare eight management setups with the ground truth (an end user watching a video on the own device) by evaluating the key performance indicators on application layer during video streaming, i.e. initial video playout delays and stalling. Our results reveal important insights: some of the common measurement setups heavily influence the measurements and must be avoided to collect reliable results.

  @inproceedings{info3-inproceedings-2019-6, abstract = {Global Internet video traffic will dramatically increase in the next years. With this rapid growth, interest in the application behavior of video streaming services and the resulting user experience rises. In particular, there is a need to understand the influence of system parameters on the streaming performance. Thus, several monitoring approaches have been developed which allow conducting automated measurements on a large-scale, for example, lightweight approaches for measurements running in the mobile networks or setups using a virtual frame buffer for servers without a display running in virtualized cloud environments. In some cases, the measurement hardware can totally be controlled, in other cases, there is no knowledge about parallel running services. In this paper, we answer the question whether and how much the measurement setup (e.g., virtualization, headless browsers, load on machines) influences the video streaming behavior. Therefore, we compare eight management setups with the ground truth (an end user watching a video on the own device) by evaluating the key performance indicators on application layer during video streaming, i.e. initial video playout delays and stalling. Our results reveal important insights: some of the common measurement setups heavily influence the measurements and must be avoided to collect reliable results.}, address = {Paris, France}, author = {Schwind, Anika and Janiak, Lea and Moldovan, Christian and Wamser, Florian and Hoßfeld, Tobias}, booktitle = {The 3rd International Workshop on Quality of Experience Management (QoE-Management 2019)}, keywords = {ua-net}, month = {02}, title = {Peeking under the Hood – How the Measurement Setup Influences the Video Streaming Behavior}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-6 %A Schwind, Anika %A Janiak, Lea %A Moldovan, Christian %A Wamser, Florian %A Hoßfeld, Tobias %B The 3rd International Workshop on Quality of Experience Management (QoE-Management 2019) %C Paris, France %D 2019 %T Peeking under the Hood – How the Measurement Setup Influences the Video Streaming Behavior %X Global Internet video traffic will dramatically increase in the next years. With this rapid growth, interest in the application behavior of video streaming services and the resulting user experience rises. In particular, there is a need to understand the influence of system parameters on the streaming performance. Thus, several monitoring approaches have been developed which allow conducting automated measurements on a large-scale, for example, lightweight approaches for measurements running in the mobile networks or setups using a virtual frame buffer for servers without a display running in virtualized cloud environments. In some cases, the measurement hardware can totally be controlled, in other cases, there is no knowledge about parallel running services. In this paper, we answer the question whether and how much the measurement setup (e.g., virtualization, headless browsers, load on machines) influences the video streaming behavior. Therefore, we compare eight management setups with the ground truth (an end user watching a video on the own device) by evaluating the key performance indicators on application layer during video streaming, i.e. initial video playout delays and stalling. Our results reveal important insights: some of the common measurement setups heavily influence the measurements and must be avoided to collect reliable results.
• The Interplay between QoE, User Behavior and System Blocking in QoE Management. Hoßfeld, Tobias; Atzori, Luigi; Heegaard, Poul E.; Skorin-Kapov, Lea; Varela, Martin. In 22nd Conference on Innovation in Clouds, Internet and Networks and Workshops (ICIN). 2019.
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  @inproceedings{info3-inproceedings-2019-15, author = {Hoßfeld, Tobias and Atzori, Luigi and Heegaard, Poul E. and Skorin-Kapov, Lea and Varela, Martin}, booktitle = {22nd Conference on Innovation in Clouds, Internet and Networks and Workshops (ICIN)}, keywords = {sys:hidden:inproceedings}, title = {The Interplay between QoE, User Behavior and System Blocking in QoE Management}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-15 %A Hoßfeld, Tobias %A Atzori, Luigi %A Heegaard, Poul E. %A Skorin-Kapov, Lea %A Varela, Martin %B 22nd Conference on Innovation in Clouds, Internet and Networks and Workshops (ICIN) %D 2019 %T The Interplay between QoE, User Behavior and System Blocking in QoE Management
• Fundamental Relationships for Deriving QoE in Systems. Hoßfeld, Tobias; Heegaard, Poul E.; Skorin-Kapov, Lea; Varela, Martin. In 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX) (QoMEX 2019). 2019.
  • [ Abstract ]
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  In the context of subjective user studies conducted to derive relationships between influence factors and QoE, user diversity leads to distributions of user scores for test conditions. Such models are commonly exploited by service/network providers to derive various QoE metrics in their system, such as expected QoE, or the percentage of users rating above a certain threshold. The question arises as to how to combine a) user rating distributions obtained from subjective studies, and b) system performance condition distributions, so as to obtain the actual observed QoE distribution in the system? Moreover, how can various QoE metrics of interest in the system be derived? We prove a fundamental relationship showing that the expected system QoE is equal to the expected Mean Opinion Score (MOS) in the system. While subjective user studies commonly report only QoS-to-MOS mapping functions, we show that to derive additional QoE metrics in the system, it is necessary to use corresponding QoS-to-QoE metric mapping functions (beyond only QoS-to-MOS) as derived from user rating distributions in subjective studies. The results of the paper provide important insights for deriving QoE metrics from a systems perspective.

  @inproceedings{info3-inproceedings-2019-23, abstract = {In the context of subjective user studies conducted to derive relationships between influence factors and QoE, user diversity leads to distributions of user scores for test conditions. Such models are commonly exploited by service/network providers to derive various QoE metrics in their system, such as expected QoE, or the percentage of users rating above a certain threshold. The question arises as to how to combine a) user rating distributions obtained from subjective studies, and b) system performance condition distributions, so as to obtain the actual observed QoE distribution in the system? Moreover, how can various QoE metrics of interest in the system be derived? We prove a fundamental relationship showing that the expected system QoE is equal to the expected Mean Opinion Score (MOS) in the system. While subjective user studies commonly report only QoS-to-MOS mapping functions, we show that to derive additional QoE metrics in the system, it is necessary to use corresponding QoS-to-QoE metric mapping functions (beyond only QoS-to-MOS) as derived from user rating distributions in subjective studies. The results of the paper provide important insights for deriving QoE metrics from a systems perspective.}, author = {Hoßfeld, Tobias and Heegaard, Poul E. and Skorin-Kapov, Lea and Varela, Martin}, booktitle = {2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX) (QoMEX 2019)}, keywords = {sys:hidden:inproceedings}, title = {Fundamental Relationships for Deriving QoE in Systems}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-23 %A Hoßfeld, Tobias %A Heegaard, Poul E. %A Skorin-Kapov, Lea %A Varela, Martin %B 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX) (QoMEX 2019) %D 2019 %T Fundamental Relationships for Deriving QoE in Systems %X In the context of subjective user studies conducted to derive relationships between influence factors and QoE, user diversity leads to distributions of user scores for test conditions. Such models are commonly exploited by service/network providers to derive various QoE metrics in their system, such as expected QoE, or the percentage of users rating above a certain threshold. The question arises as to how to combine a) user rating distributions obtained from subjective studies, and b) system performance condition distributions, so as to obtain the actual observed QoE distribution in the system? Moreover, how can various QoE metrics of interest in the system be derived? We prove a fundamental relationship showing that the expected system QoE is equal to the expected Mean Opinion Score (MOS) in the system. While subjective user studies commonly report only QoS-to-MOS mapping functions, we show that to derive additional QoE metrics in the system, it is necessary to use corresponding QoS-to-QoE metric mapping functions (beyond only QoS-to-MOS) as derived from user rating distributions in subjective studies. The results of the paper provide important insights for deriving QoE metrics from a systems perspective.
• Online Detection of Stalling and Scrubbing in Adaptive Video Streaming. Maggi, Lorenzo; Leguay, Jeremy; Seufert, Michael; Casas, Pedro. In 17th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt). Avignon, France, 2019.
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  @inproceedings{info3-inproceedings-2019-12, address = {Avignon, France}, author = {Maggi, Lorenzo and Leguay, Jeremy and Seufert, Michael and Casas, Pedro}, booktitle = {17th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt)}, keywords = {net-man}, month = {06}, title = {Online Detection of Stalling and Scrubbing in Adaptive Video Streaming}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-12 %A Maggi, Lorenzo %A Leguay, Jeremy %A Seufert, Michael %A Casas, Pedro %B 17th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt) %C Avignon, France %D 2019 %T Online Detection of Stalling and Scrubbing in Adaptive Video Streaming
• Features that Matter: Feature Selection for On-line Stalling Prediction in Encrypted Video Streaming. Seufert, Michael; Casas, Pedro; Wehner, Nikolas; Li, Gang; Kuang, Li. In 2nd International Workshop on Network Intelligence (NI). Paris, France, 2019.
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  @inproceedings{info3-inproceedings-2019-11, address = {Paris, France}, author = {Seufert, Michael and Casas, Pedro and Wehner, Nikolas and Li, Gang and Kuang, Li}, booktitle = {2nd International Workshop on Network Intelligence (NI)}, keywords = {net-man}, month = {04}, title = {Features that Matter: Feature Selection for On-line Stalling Prediction in Encrypted Video Streaming}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-11 %A Seufert, Michael %A Casas, Pedro %A Wehner, Nikolas %A Li, Gang %A Kuang, Li %B 2nd International Workshop on Network Intelligence (NI) %C Paris, France %D 2019 %T Features that Matter: Feature Selection for On-line Stalling Prediction in Encrypted Video Streaming
• Discrete-Time Modeling of NFV Accelerators that Exploit Batched Processing. Lange, Stanislav; Linguaglossa, Leonardo; Geissler, Stefan; Rossi, Dario; Zinner, Thomas. In IEEE Conference on Computer Communications (Infocom). 2019.
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  @inproceedings{info3-inproceedings-2019-4, author = {Lange, Stanislav and Linguaglossa, Leonardo and Geissler, Stefan and Rossi, Dario and Zinner, Thomas}, booktitle = {IEEE Conference on Computer Communications (Infocom)}, keywords = {sendate}, month = {04}, title = {Discrete-Time Modeling of NFV Accelerators that Exploit Batched Processing}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-4 %A Lange, Stanislav %A Linguaglossa, Leonardo %A Geissler, Stefan %A Rossi, Dario %A Zinner, Thomas %B IEEE Conference on Computer Communications (Infocom) %D 2019 %T Discrete-Time Modeling of NFV Accelerators that Exploit Batched Processing
• User Behavior and Engagement of a Mobile Video Streaming User from Crowdsourced Measurements. Moldovan, Christian; Wamser, Florian; Hoßfeld, Tobias. In 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX). 2019.
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  Mobile video streaming has gained a lot of popularity in recent year with the introduction of large data plans for mobile phones. While users in non-mobile scenarios have become accustomed to high quality and few stalling events, this is not the case in mobile environments. People are more likely to tolerate stalling since they know high throughput coverage cannot always be guaranteed. Their behavior and their engagement are drastically different when watching videos on mobile devices. In this paper, we characterize mobile phone users who use a video streaming application. We present a data set of over 6,000 video views from a crowdsourced video measurement study. We investigate user activity and engagement during video streaming and how such metrics are correlated with each other. This is the first study that goes beyond user engagement and investigates the direct behavior of mobile video users outside the lab which is an important step towards mobile QoE management.

  @inproceedings{info3-inproceedings-2019-21, abstract = {Mobile video streaming has gained a lot of popularity in recent year with the introduction of large data plans for mobile phones. While users in non-mobile scenarios have become accustomed to high quality and few stalling events, this is not the case in mobile environments. People are more likely to tolerate stalling since they know high throughput coverage cannot always be guaranteed. Their behavior and their engagement are drastically different when watching videos on mobile devices. In this paper, we characterize mobile phone users who use a video streaming application. We present a data set of over 6,000 video views from a crowdsourced video measurement study. We investigate user activity and engagement during video streaming and how such metrics are correlated with each other. This is the first study that goes beyond user engagement and investigates the direct behavior of mobile video users outside the lab which is an important step towards mobile QoE management.}, author = {Moldovan, Christian and Wamser, Florian and Hoßfeld, Tobias}, booktitle = {2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {can}, month = {06}, title = {User Behavior and Engagement of a Mobile Video Streaming User from Crowdsourced Measurements}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-21 %A Moldovan, Christian %A Wamser, Florian %A Hoßfeld, Tobias %B 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX) %D 2019 %T User Behavior and Engagement of a Mobile Video Streaming User from Crowdsourced Measurements %X Mobile video streaming has gained a lot of popularity in recent year with the introduction of large data plans for mobile phones. While users in non-mobile scenarios have become accustomed to high quality and few stalling events, this is not the case in mobile environments. People are more likely to tolerate stalling since they know high throughput coverage cannot always be guaranteed. Their behavior and their engagement are drastically different when watching videos on mobile devices. In this paper, we characterize mobile phone users who use a video streaming application. We present a data set of over 6,000 video views from a crowdsourced video measurement study. We investigate user activity and engagement during video streaming and how such metrics are correlated with each other. This is the first study that goes beyond user engagement and investigates the direct behavior of mobile video users outside the lab which is an important step towards mobile QoE management.
• On the Analysis of YouTube QoE in Cellular Networks through in-Smartphone Measurements. Wassermann, Sarah; Casas, Pedro; Seufert, Michael; Wamser, Florian. In 12th IFIP Wireless and Mobile Networking Conference (WMNC). Paris, France, 2019.
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  @inproceedings{info3-inproceedings-2019-18, address = {Paris, France}, author = {Wassermann, Sarah and Casas, Pedro and Seufert, Michael and Wamser, Florian}, booktitle = {12th IFIP Wireless and Mobile Networking Conference (WMNC)}, keywords = {ua-net}, month = {09}, title = {On the Analysis of YouTube QoE in Cellular Networks through in-Smartphone Measurements}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-18 %A Wassermann, Sarah %A Casas, Pedro %A Seufert, Michael %A Wamser, Florian %B 12th IFIP Wireless and Mobile Networking Conference (WMNC) %C Paris, France %D 2019 %T On the Analysis of YouTube QoE in Cellular Networks through in-Smartphone Measurements
• QoE Analysis of Spotify Audio Streaming and App Browsing. Schwind, Anika; Haberzettl, Lorenz; Wamser, Florian; Hoßfeld, Tobias. In 4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks (Internet-QoE’19). 2019.
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  Spotify is the most-listened audio streaming provider in 2019 with 217 million active users per month. Providers are therefore interested in the quality and functionality of Spotify in order to provide their users with the best possible streaming quality. While video streaming services such as Netflix and their streaming approach have been extensively explored in previous research, audio streaming services like Spotify and their corresponding behavior at certain network conditions have not been considered in detail yet. In this paper, we perform a QoE analysis under various network conditions and examine the app browsing performance of the audio streaming platform Spotify using its native Android mobile application. We have developed a measurement tool that emulates a user listening to audio through Spotify. While streaming, application and network layer parameters are captured that have a high correlation to the user’s QoE. The paper shows a baseline scenario including the streaming of a single song as well as playlist streaming behavior. Next, the effect of interruptions on the streaming behavior is evaluated and finally, the influence of network impairments on QoE key performance indicators such as initial delay is shown.

  @inproceedings{info3-inproceedings-2019-27, abstract = {Spotify is the most-listened audio streaming provider in 2019 with 217 million active users per month. Providers are therefore interested in the quality and functionality of Spotify in order to provide their users with the best possible streaming quality. While video streaming services such as Netflix and their streaming approach have been extensively explored in previous research, audio streaming services like Spotify and their corresponding behavior at certain network conditions have not been considered in detail yet. In this paper, we perform a QoE analysis under various network conditions and examine the app browsing performance of the audio streaming platform Spotify using its native Android mobile application. We have developed a measurement tool that emulates a user listening to audio through Spotify. While streaming, application and network layer parameters are captured that have a high correlation to the user’s QoE. The paper shows a baseline scenario including the streaming of a single song as well as playlist streaming behavior. Next, the effect of interruptions on the streaming behavior is evaluated and finally, the influence of network impairments on QoE key performance indicators such as initial delay is shown.}, author = {Schwind, Anika and Haberzettl, Lorenz and Wamser, Florian and Hoßfeld, Tobias}, booktitle = {4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks (Internet-QoE'19)}, keywords = {can}, month = 10, title = {QoE Analysis of Spotify Audio Streaming and App Browsing}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-27 %A Schwind, Anika %A Haberzettl, Lorenz %A Wamser, Florian %A Hoßfeld, Tobias %B 4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks (Internet-QoE'19) %D 2019 %T QoE Analysis of Spotify Audio Streaming and App Browsing %X Spotify is the most-listened audio streaming provider in 2019 with 217 million active users per month. Providers are therefore interested in the quality and functionality of Spotify in order to provide their users with the best possible streaming quality. While video streaming services such as Netflix and their streaming approach have been extensively explored in previous research, audio streaming services like Spotify and their corresponding behavior at certain network conditions have not been considered in detail yet. In this paper, we perform a QoE analysis under various network conditions and examine the app browsing performance of the audio streaming platform Spotify using its native Android mobile application. We have developed a measurement tool that emulates a user listening to audio through Spotify. While streaming, application and network layer parameters are captured that have a high correlation to the user’s QoE. The paper shows a baseline scenario including the streaming of a single song as well as playlist streaming behavior. Next, the effect of interruptions on the streaming behavior is evaluated and finally, the influence of network impairments on QoE key performance indicators such as initial delay is shown.
• I See What you See: Real Time Prediction of Video Quality from Encrypted Streaming Traffic. Wassermann, Sarah; Seufert, Michael; Casas, Pedro; Li, Gang; Kuang, Li. In 4th Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE). Los Cabos, Mexico, 2019.
  • [ Abstract ]
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  We address the problem of real-time QoE monitoring of HAS, from the ISP perspective, focusing in particular on videoresolution analysis. Given the wide adoption of end-to-end encryption, we resort to machine-learning models to predict different video resolution levels in a fine-grained scale, ranging from 144p to 1080p resolution, using as input only packet-level data. The proposed measurement system performs predictions in real time, during the course of an ongoing video-streaming session, with a time granularity as small as one second. We consider the particular case of YouTube video streaming. Empirical evaluations on a large and heterogeneous corpus of YouTube measurements demonstrate that the proposed system can predict video resolution with very high accuracy, and in real time. Different from state of the art, the prediction task is not bound to coarse-grained video quality classes and does not require chunk-detection approaches for feature extraction.

  @inproceedings{info3-inproceedings-2019-28, abstract = {We address the problem of real-time QoE monitoring of HAS, from the ISP perspective, focusing in particular on videoresolution analysis. Given the wide adoption of end-to-end encryption, we resort to machine-learning models to predict different video resolution levels in a fine-grained scale, ranging from 144p to 1080p resolution, using as input only packet-level data. The proposed measurement system performs predictions in real time, during the course of an ongoing video-streaming session, with a time granularity as small as one second. We consider the particular case of YouTube video streaming. Empirical evaluations on a large and heterogeneous corpus of YouTube measurements demonstrate that the proposed system can predict video resolution with very high accuracy, and in real time. Different from state of the art, the prediction task is not bound to coarse-grained video quality classes and does not require chunk-detection approaches for feature extraction.}, address = {Los Cabos, Mexico}, author = {Wassermann, Sarah and Seufert, Michael and Casas, Pedro and Li, Gang and Kuang, Li}, booktitle = {4th Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE)}, keywords = {ua-net}, month = 10, title = {I See What you See: Real Time Prediction of Video Quality from Encrypted Streaming Traffic}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-28 %A Wassermann, Sarah %A Seufert, Michael %A Casas, Pedro %A Li, Gang %A Kuang, Li %B 4th Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE) %C Los Cabos, Mexico %D 2019 %T I See What you See: Real Time Prediction of Video Quality from Encrypted Streaming Traffic %X We address the problem of real-time QoE monitoring of HAS, from the ISP perspective, focusing in particular on videoresolution analysis. Given the wide adoption of end-to-end encryption, we resort to machine-learning models to predict different video resolution levels in a fine-grained scale, ranging from 144p to 1080p resolution, using as input only packet-level data. The proposed measurement system performs predictions in real time, during the course of an ongoing video-streaming session, with a time granularity as small as one second. We consider the particular case of YouTube video streaming. Empirical evaluations on a large and heterogeneous corpus of YouTube measurements demonstrate that the proposed system can predict video resolution with very high accuracy, and in real time. Different from state of the art, the prediction task is not bound to coarse-grained video quality classes and does not require chunk-detection approaches for feature extraction.
• Traffic Measurement Study on Video Streaming with the Amazon Echo Show. Loh, Frank; Vomhoff, Viktoria; Wamser, Florian; Metzger, Florian; Hoßfeld, Tobias. In 4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks. 2019.
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  The Amazon Echo Show is one of the most widely used smart speakers with the ability to stream video. Due to its popularity, the traffc profiles of such devices are of interest to network operators and providers. This work presents a measurement study of the Amazon Echo Show in terms of network traffc and streaming behavior. More than 470 hours of streaming data are collected and analyzed at network layer. Based on this, streaming quality is derived at application layer. The study quantifies the traffc and shows that streaming with the Amazon Echo Show is comparable to streaming with a native web browser, but in a more conservative way.

  @inproceedings{info3-inproceedings-2019-26, abstract = {The Amazon Echo Show is one of the most widely used smart speakers with the ability to stream video. Due to its popularity, the traffc profiles of such devices are of interest to network operators and providers. This work presents a measurement study of the Amazon Echo Show in terms of network traffc and streaming behavior. More than 470 hours of streaming data are collected and analyzed at network layer. Based on this, streaming quality is derived at application layer. The study quantifies the traffc and shows that streaming with the Amazon Echo Show is comparable to streaming with a native web browser, but in a more conservative way.}, author = {Loh, Frank and Vomhoff, Viktoria and Wamser, Florian and Metzger, Florian and Hoßfeld, Tobias}, booktitle = {4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks}, keywords = {can}, month = 10, title = {Traffic Measurement Study on Video Streaming with the Amazon Echo Show}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-26 %A Loh, Frank %A Vomhoff, Viktoria %A Wamser, Florian %A Metzger, Florian %A Hoßfeld, Tobias %B 4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks %D 2019 %T Traffic Measurement Study on Video Streaming with the Amazon Echo Show %X The Amazon Echo Show is one of the most widely used smart speakers with the ability to stream video. Due to its popularity, the traffc profiles of such devices are of interest to network operators and providers. This work presents a measurement study of the Amazon Echo Show in terms of network traffc and streaming behavior. More than 470 hours of streaming data are collected and analyzed at network layer. Based on this, streaming quality is derived at application layer. The study quantifies the traffc and shows that streaming with the Amazon Echo Show is comparable to streaming with a native web browser, but in a more conservative way.
• Crowd-based Study of Gameplay Impairments and Player Performance in DOTA 2. Hirth, Matthias; Borchert, Kathrin; Allendorf, Fabian; Metzger, Florian; Hoßfeld, Tobias. In 4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks (Internet-QoE’19). Los Cabos, Mexico, 2019.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2019-24, address = {Los Cabos, Mexico}, author = {Hirth, Matthias and Borchert, Kathrin and Allendorf, Fabian and Metzger, Florian and Hoßfeld, Tobias}, booktitle = {4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks (Internet-QoE'19)}, keywords = {ua-net}, month = 10, title = {Crowd-based Study of Gameplay Impairments and Player Performance in DOTA 2}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-24 %A Hirth, Matthias %A Borchert, Kathrin %A Allendorf, Fabian %A Metzger, Florian %A Hoßfeld, Tobias %B 4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks (Internet-QoE'19) %C Los Cabos, Mexico %D 2019 %T Crowd-based Study of Gameplay Impairments and Player Performance in DOTA 2
• Crowd-based Assessment of Deformational Cranial Asymmetries. Borchert, Kathrin; Hirth, Matthias; Stellzig-Eisenhauer, Angelika; Kunz, Felix. In International Workshop on Crowd-Powered e-Services (CROPS). Trondheim, Norway, 2019.
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  @inproceedings{info3-inproceedings-2019-17, address = {Trondheim, Norway}, author = {Borchert, Kathrin and Hirth, Matthias and Stellzig-Eisenhauer, Angelika and Kunz, Felix}, booktitle = {International Workshop on Crowd-Powered e-Services (CROPS)}, keywords = {ua-net}, month = {09}, title = {Crowd-based Assessment of Deformational Cranial Asymmetries}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-17 %A Borchert, Kathrin %A Hirth, Matthias %A Stellzig-Eisenhauer, Angelika %A Kunz, Felix %B International Workshop on Crowd-Powered e-Services (CROPS) %C Trondheim, Norway %D 2019 %T Crowd-based Assessment of Deformational Cranial Asymmetries
• Modeling of Traffic Flows in Internet of Things Using Renewal Approximation. Wamser, Florian; Tran-Gia, Phuoc; Geissler, Stefan; Hoßfeld, Tobias. In International Conference on Optimization and Decision Science (ODS2019). 2019.
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  This paper proposes a versatile approach to model aggregated traffic flows in the Internet of Things (IoT) using renewal approximation. The modeled traffic originates from a large number of sources or devices consisting of a set of sensors mixed with classical elastic random traffic modeled as Poisson arrival process. The work shows the exact derivation in the simple case for periodic sensors. It shows further results in the mixed case with periodic sensors and a background process. The renewal approximation allows to derive the required number of sensors such that the aggregated traffic can be approximated as Poisson process.

  @inproceedings{info3-article-2019-8, abstract = {This paper proposes a versatile approach to model aggregated traffic flows in the Internet of Things (IoT) using renewal approximation. The modeled traffic originates from a large number of sources or devices consisting of a set of sensors mixed with classical elastic random traffic modeled as Poisson arrival process. The work shows the exact derivation in the simple case for periodic sensors. It shows further results in the mixed case with periodic sensors and a background process. The renewal approximation allows to derive the required number of sensors such that the aggregated traffic can be approximated as Poisson process.}, author = {Wamser, Florian and Tran-Gia, Phuoc and Geissler, Stefan and Hoßfeld, Tobias}, booktitle = {International Conference on Optimization and Decision Science (ODS2019)}, keywords = {can}, month = {09}, title = {Modeling of Traffic Flows in Internet of Things Using Renewal Approximation}, year = 2019 }

  %0 Conference Paper %1 info3-article-2019-8 %A Wamser, Florian %A Tran-Gia, Phuoc %A Geissler, Stefan %A Hoßfeld, Tobias %B International Conference on Optimization and Decision Science (ODS2019) %D 2019 %T Modeling of Traffic Flows in Internet of Things Using Renewal Approximation %X This paper proposes a versatile approach to model aggregated traffic flows in the Internet of Things (IoT) using renewal approximation. The modeled traffic originates from a large number of sources or devices consisting of a set of sensors mixed with classical elastic random traffic modeled as Poisson arrival process. The work shows the exact derivation in the simple case for periodic sensors. It shows further results in the mixed case with periodic sensors and a background process. The renewal approximation allows to derive the required number of sensors such that the aggregated traffic can be approximated as Poisson process.
• Discrete-Time Analysis of the Blockchain Distributed Ledger Technology. Geissler, Stefan; Prantl, Thomas; Lange, Stanislav; Wamser, Florian; Hoßfeld, Tobias. In 31st International Teletraffic Congress (ITC). , Budapest, Hungary. 2019.
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  Blockchain and distributed ledger technologies have become more and more popular and widespread during recent years. After the initial hype about the technology and many cryptocurrency related use cases, the technology slowly starts to make its way into other domains like food tracking and document management. In order to further contribute to the search of what this technology can be used for, more detailed performance evaluations are required in order to investigate key performance indicators and general limits of the technology. To this end, we develop a discrete-time queueing model that allows a detailed evaluation of the characteristics of a blockchain system, such as the transaction waiting time distribution. Furthermore, we validate the model by comparing the results to values obtained from measurements in a closed lab environment based on the Ethereum blockchain.

  @inproceedings{info3-inproceedings-2019-19, abstract = {Blockchain and distributed ledger technologies have become more and more popular and widespread during recent years. After the initial hype about the technology and many cryptocurrency related use cases, the technology slowly starts to make its way into other domains like food tracking and document management. In order to further contribute to the search of what this technology can be used for, more detailed performance evaluations are required in order to investigate key performance indicators and general limits of the technology. To this end, we develop a discrete-time queueing model that allows a detailed evaluation of the characteristics of a blockchain system, such as the transaction waiting time distribution. Furthermore, we validate the model by comparing the results to values obtained from measurements in a closed lab environment based on the Ethereum blockchain.}, author = {Geissler, Stefan and Prantl, Thomas and Lange, Stanislav and Wamser, Florian and Hoßfeld, Tobias}, booktitle = {31st International Teletraffic Congress (ITC). , Budapest, Hungary}, keywords = {net-man}, month = {08}, title = {Discrete-Time Analysis of the Blockchain Distributed Ledger Technology}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-19 %A Geissler, Stefan %A Prantl, Thomas %A Lange, Stanislav %A Wamser, Florian %A Hoßfeld, Tobias %B 31st International Teletraffic Congress (ITC). , Budapest, Hungary %D 2019 %T Discrete-Time Analysis of the Blockchain Distributed Ledger Technology %X Blockchain and distributed ledger technologies have become more and more popular and widespread during recent years. After the initial hype about the technology and many cryptocurrency related use cases, the technology slowly starts to make its way into other domains like food tracking and document management. In order to further contribute to the search of what this technology can be used for, more detailed performance evaluations are required in order to investigate key performance indicators and general limits of the technology. To this end, we develop a discrete-time queueing model that allows a detailed evaluation of the characteristics of a blockchain system, such as the transaction waiting time distribution. Furthermore, we validate the model by comparing the results to values obtained from measurements in a closed lab environment based on the Ethereum blockchain.
• Task Scheduling on Crowdsourcing Platforms for Enabling Completion Time SLAs. Hirth, Matthias; Steurer, Florian; Borchert, Kathrin; Dubiner, Dan. In 31st International Teletraffic Congress (ITC). Budapest, Hungary, 2019.
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  @inproceedings{info3-inproceedings-2019-20, address = {Budapest, Hungary}, author = {Hirth, Matthias and Steurer, Florian and Borchert, Kathrin and Dubiner, Dan}, booktitle = {31st International Teletraffic Congress (ITC)}, keywords = {ua-net}, month = {08}, title = {Task Scheduling on Crowdsourcing Platforms for Enabling Completion Time SLAs}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-20 %A Hirth, Matthias %A Steurer, Florian %A Borchert, Kathrin %A Dubiner, Dan %B 31st International Teletraffic Congress (ITC) %C Budapest, Hungary %D 2019 %T Task Scheduling on Crowdsourcing Platforms for Enabling Completion Time SLAs
• Fundamental Advantages of Considering Quality of Experience Distributions over Mean Opinion Scores. Seufert, Michael. In 11th International Conference on Quality of Multimedia Experience (QoMEX). Berlin, Germany, 2019.
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  @inproceedings{info3-inproceedings-2019-14, address = {Berlin, Germany}, author = {Seufert, Michael}, booktitle = {11th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ua-net}, month = {06}, title = {Fundamental Advantages of Considering Quality of Experience Distributions over Mean Opinion Scores}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-14 %A Seufert, Michael %B 11th International Conference on Quality of Multimedia Experience (QoMEX) %C Berlin, Germany %D 2019 %T Fundamental Advantages of Considering Quality of Experience Distributions over Mean Opinion Scores
• In Vivo or in Vitro? Influence of the Study Design on Crowdsourced Video QoE. Borchert, Kathrin; Schwind, Anika; Hirth, Matthias; Hoßfeld, Tobias. In 11th International Conference on Quality of Multimedia Experience (QoMEX). 2019.
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  @inproceedings{info3-inproceedings-2019-10, author = {Borchert, Kathrin and Schwind, Anika and Hirth, Matthias and Hoßfeld, Tobias}, booktitle = {11th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ua-net}, month = {06}, title = {In Vivo or in Vitro? Influence of the Study Design on Crowdsourced Video QoE}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-10 %A Borchert, Kathrin %A Schwind, Anika %A Hirth, Matthias %A Hoßfeld, Tobias %B 11th International Conference on Quality of Multimedia Experience (QoMEX) %D 2019 %T In Vivo or in Vitro? Influence of the Study Design on Crowdsourced Video QoE
• From click to playback: a dataset to study the response time of mobile YouTube. Loh, Frank; Wamser, Florian; Moldovan, Christian; Zeidler, Bernd; Hoßfeld, Tobias; Tsilimantos, Dimitrios; Valentin, Stefan. In Proceedings of the 10th ACM Multimedia Systems Conference, pp. 267–272. 2019.
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  Responding fluently to user requests is important to keep them immersed. In this paper, we are presenting an extensive dataset to study the response time of YouTube's mobile video streaming service on Android. We illustrate the application of our dataset by studying YouTube's initial delay for a subset of 9 videos in 75 network scenarios. We find that in 41% of the cases, YouTube exceeds the attention span of a typical user, while deep immersion is only reached in 15% of the cases. Our factor analysis implies that the allocation of the initial CDN node is the critical link in this delay chain. Since our dataset includes a large variety of factors, we are describing setup, methodology, and data structure in detail. Our dataset and measurement tools are publicly available.

  @inproceedings{info3-inproceedings-2019-25, abstract = {Responding fluently to user requests is important to keep them immersed. In this paper, we are presenting an extensive dataset to study the response time of YouTube's mobile video streaming service on Android. We illustrate the application of our dataset by studying YouTube's initial delay for a subset of 9 videos in 75 network scenarios. We find that in 41% of the cases, YouTube exceeds the attention span of a typical user, while deep immersion is only reached in 15% of the cases. Our factor analysis implies that the allocation of the initial CDN node is the critical link in this delay chain. Since our dataset includes a large variety of factors, we are describing setup, methodology, and data structure in detail. Our dataset and measurement tools are publicly available.}, author = {Loh, Frank and Wamser, Florian and Moldovan, Christian and Zeidler, Bernd and Hoßfeld, Tobias and Tsilimantos, Dimitrios and Valentin, Stefan}, booktitle = {Proceedings of the 10th ACM Multimedia Systems Conference}, keywords = {can}, month = {06}, pages = {267-272}, title = {From click to playback: a dataset to study the response time of mobile YouTube}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-25 %A Loh, Frank %A Wamser, Florian %A Moldovan, Christian %A Zeidler, Bernd %A Hoßfeld, Tobias %A Tsilimantos, Dimitrios %A Valentin, Stefan %B Proceedings of the 10th ACM Multimedia Systems Conference %D 2019 %P 267-272 %T From click to playback: a dataset to study the response time of mobile YouTube %X Responding fluently to user requests is important to keep them immersed. In this paper, we are presenting an extensive dataset to study the response time of YouTube's mobile video streaming service on Android. We illustrate the application of our dataset by studying YouTube's initial delay for a subset of 9 videos in 75 network scenarios. We find that in 41% of the cases, YouTube exceeds the attention span of a typical user, while deep immersion is only reached in 15% of the cases. Our factor analysis implies that the allocation of the initial CDN node is the critical link in this delay chain. Since our dataset includes a large variety of factors, we are describing setup, methodology, and data structure in detail. Our dataset and measurement tools are publicly available.
• To Share or Not to Share? How Exploitation of Context Data Can Improve In-Network QoE Monitoring of Encrypted YouTube Streams. Orsolic, Irena; Skorin-Kapov, Lea; Hoßfeld, Tobias. In 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX) (QoMEX 2019). 2019.
  • [ Abstract ]
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  With the widespread use of encryption in Over the Top (OTT) traffic, Internet Service Providers (ISPs) for the most part lack insights into application performance, as well as into Quality of Experience (QoE) perceived by end users. Addressing challenges related to encryption, ISPs are looking into machine learning based solutions that can detect application performance solely from statistical properties of the traffic. On the other hand, OTT service providers are not willing to share service performance and content-related information with ISPs. While related work on OTT-ISP collaboration scenarios has addressed architectural aspects, business models, and to a certain extent incentives for sharing data, the focus of this paper is on the exchanged data itself. We investigate to what extent the performance of in-network machine learning based QoE estimation models for HTTP adaptive video streaming could be improved with the availability of certain context data provided by OTT providers. We motivate OTT-ISP collaboration through more accurate in-network QoE monitoring and potential improvement of user experience, which is of interest to both sides.

  @inproceedings{info3-article-2019-9, abstract = {With the widespread use of encryption in Over the Top (OTT) traffic, Internet Service Providers (ISPs) for the most part lack insights into application performance, as well as into Quality of Experience (QoE) perceived by end users. Addressing challenges related to encryption, ISPs are looking into machine learning based solutions that can detect application performance solely from statistical properties of the traffic. On the other hand, OTT service providers are not willing to share service performance and content-related information with ISPs. While related work on OTT-ISP collaboration scenarios has addressed architectural aspects, business models, and to a certain extent incentives for sharing data, the focus of this paper is on the exchanged data itself. We investigate to what extent the performance of in-network machine learning based QoE estimation models for HTTP adaptive video streaming could be improved with the availability of certain context data provided by OTT providers. We motivate OTT-ISP collaboration through more accurate in-network QoE monitoring and potential improvement of user experience, which is of interest to both sides.}, author = {Orsolic, Irena and Skorin-Kapov, Lea and Hoßfeld, Tobias}, booktitle = {2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX) (QoMEX 2019)}, keywords = {YouTube}, month = {06}, title = {To Share or Not to Share? How Exploitation of Context Data Can Improve In-Network QoE Monitoring of Encrypted YouTube Streams}, year = 2019 }

  %0 Conference Paper %1 info3-article-2019-9 %A Orsolic, Irena %A Skorin-Kapov, Lea %A Hoßfeld, Tobias %B 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX) (QoMEX 2019) %D 2019 %T To Share or Not to Share? How Exploitation of Context Data Can Improve In-Network QoE Monitoring of Encrypted YouTube Streams %X With the widespread use of encryption in Over the Top (OTT) traffic, Internet Service Providers (ISPs) for the most part lack insights into application performance, as well as into Quality of Experience (QoE) perceived by end users. Addressing challenges related to encryption, ISPs are looking into machine learning based solutions that can detect application performance solely from statistical properties of the traffic. On the other hand, OTT service providers are not willing to share service performance and content-related information with ISPs. While related work on OTT-ISP collaboration scenarios has addressed architectural aspects, business models, and to a certain extent incentives for sharing data, the focus of this paper is on the exchanged data itself. We investigate to what extent the performance of in-network machine learning based QoE estimation models for HTTP adaptive video streaming could be improved with the availability of certain context data provided by OTT providers. We motivate OTT-ISP collaboration through more accurate in-network QoE monitoring and potential improvement of user experience, which is of interest to both sides.
• Is QUIC becoming the New TCP? On the Potential Impact of a New Protocol on Networked Multimedia QoE. Seufert, Michael; Schatz, Raimund; Wehner, Nikolas; Gardlo, Bruno; Casas, Pedro. In 11th International Conference on Quality of Multimedia Experience (QoMEX). Berlin, Germany, 2019.
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  @inproceedings{info3-inproceedings-2019-13, address = {Berlin, Germany}, author = {Seufert, Michael and Schatz, Raimund and Wehner, Nikolas and Gardlo, Bruno and Casas, Pedro}, booktitle = {11th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ua-net}, month = {06}, title = {Is QUIC becoming the New TCP? On the Potential Impact of a New Protocol on Networked Multimedia QoE}, year = 2019 }

  %0 Conference Paper %1 info3-inproceedings-2019-13 %A Seufert, Michael %A Schatz, Raimund %A Wehner, Nikolas %A Gardlo, Bruno %A Casas, Pedro %B 11th International Conference on Quality of Multimedia Experience (QoMEX) %C Berlin, Germany %D 2019 %T Is QUIC becoming the New TCP? On the Potential Impact of a New Protocol on Networked Multimedia QoE

• Pervasive Communities in the Internet of People. Lagerspetz, Eemil; Flores, Huber; Mäkitalo, Niko; Hui, Pan; Nurmi, Petteri; Tarkoma, Sasu; Passarella, Andrea; Ott, Jörg; Reichl, Peter; Conti, Marco; Fiedler, Markus; Singh, Jatinder; Strufe, Thorsten; Hoßfeld, Tobias. In Proceedings of the 1st International Workshop on Context-Awareness for Multi-Device Pervasive and Mobile Computing (PerCrowd). Athens, Greece, 2018.
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  @inproceedings{info3-inproceedings-2018-5, address = {Athens, Greece}, author = {Lagerspetz, Eemil and Flores, Huber and Mäkitalo, Niko and Hui, Pan and Nurmi, Petteri and Tarkoma, Sasu and Passarella, Andrea and Ott, Jörg and Reichl, Peter and Conti, Marco and Fiedler, Markus and Singh, Jatinder and Strufe, Thorsten and Hoßfeld, Tobias}, booktitle = {Proceedings of the 1st International Workshop on Context-Awareness for Multi-Device Pervasive and Mobile Computing (PerCrowd)}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Pervasive Communities in the Internet of People}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-5 %A Lagerspetz, Eemil %A Flores, Huber %A Mäkitalo, Niko %A Hui, Pan %A Nurmi, Petteri %A Tarkoma, Sasu %A Passarella, Andrea %A Ott, Jörg %A Reichl, Peter %A Conti, Marco %A Fiedler, Markus %A Singh, Jatinder %A Strufe, Thorsten %A Hoßfeld, Tobias %B Proceedings of the 1st International Workshop on Context-Awareness for Multi-Device Pervasive and Mobile Computing (PerCrowd) %C Athens, Greece %D 2018 %T Pervasive Communities in the Internet of People
• Streaming Characteristics of Spotify Sessions. Schwind, Anika; Wamser, Florian; Gensler, Thomas; Seufert, Michael; Casas, Pedro; Tran-Gia, Phuoc. In The 2nd International Workshop on Quality of Experience Management. Sardinia, Italy, 2018.
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  Internet Service Providers need a thorough understanding of a service to maximize the Quality of Experience (QoE) of their customers by network management. Instead of quantifying the user satisfaction with long and cost-intensive subjective user studies, the QoE can often be estimated with the help of dedicated measurements of application and network parameters. We designed a QoE measurement tool for the popular audio streaming service Spotify that runs inside a Docker software container. The container is able to run headlessly as active measurement probe and emulates a user who is streaming audio files via Spotify. While streaming, network and application parameters are collected that have a high correlation to the user's QoE. The results of the measurements are used to characterize audio streaming in Spotify on application and network layer, and to evaluate important QoE factors.

  @inproceedings{info3-inproceedings-2018-13, abstract = {Internet Service Providers need a thorough understanding of a service to maximize the Quality of Experience (QoE) of their customers by network management. Instead of quantifying the user satisfaction with long and cost-intensive subjective user studies, the QoE can often be estimated with the help of dedicated measurements of application and network parameters. We designed a QoE measurement tool for the popular audio streaming service Spotify that runs inside a Docker software container. The container is able to run headlessly as active measurement probe and emulates a user who is streaming audio files via Spotify. While streaming, network and application parameters are collected that have a high correlation to the user's QoE. The results of the measurements are used to characterize audio streaming in Spotify on application and network layer, and to evaluate important QoE factors.}, address = {Sardinia, Italy}, author = {Schwind, Anika and Wamser, Florian and Gensler, Thomas and Seufert, Michael and Casas, Pedro and Tran-Gia, Phuoc}, booktitle = {The 2nd International Workshop on Quality of Experience Management}, keywords = {can}, month = {05}, title = {Streaming Characteristics of Spotify Sessions}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-13 %A Schwind, Anika %A Wamser, Florian %A Gensler, Thomas %A Seufert, Michael %A Casas, Pedro %A Tran-Gia, Phuoc %B The 2nd International Workshop on Quality of Experience Management %C Sardinia, Italy %D 2018 %T Streaming Characteristics of Spotify Sessions %X Internet Service Providers need a thorough understanding of a service to maximize the Quality of Experience (QoE) of their customers by network management. Instead of quantifying the user satisfaction with long and cost-intensive subjective user studies, the QoE can often be estimated with the help of dedicated measurements of application and network parameters. We designed a QoE measurement tool for the popular audio streaming service Spotify that runs inside a Docker software container. The container is able to run headlessly as active measurement probe and emulates a user who is streaming audio files via Spotify. While streaming, network and application parameters are collected that have a high correlation to the user's QoE. The results of the measurements are used to characterize audio streaming in Spotify on application and network layer, and to evaluate important QoE factors.
• Identification of Delay Thresholds Representing the Perceived Quality of Enterprise Applications. Borchert, Kathrin; Lange, Stanislav; Zinner, Thomas; Hirth, Matthias. In The 2nd International Workshop on Quality of Experience Management. Sardinia, Italy, 2018.
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  @inproceedings{info3-inproceedings-2018-11, address = {Sardinia, Italy}, author = {Borchert, Kathrin and Lange, Stanislav and Zinner, Thomas and Hirth, Matthias}, booktitle = {The 2nd International Workshop on Quality of Experience Management}, keywords = {ua-net}, month = {05}, title = {Identification of Delay Thresholds Representing the Perceived Quality of Enterprise Applications}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-11 %A Borchert, Kathrin %A Lange, Stanislav %A Zinner, Thomas %A Hirth, Matthias %B The 2nd International Workshop on Quality of Experience Management %C Sardinia, Italy %D 2018 %T Identification of Delay Thresholds Representing the Perceived Quality of Enterprise Applications
• Evaluation of the Benefits of Variable Segment Durations for Adaptive Streaming. Schwarzmann, Susanna; Zinner, Thomas; Sieber, Christian; Geissler, Stefan. In The 2nd International Workshop on Quality of Experience Management. Sardinia, Italy, 2018.
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  HTTP Adaptive Streaming (HAS) is the de-facto standard for video delivery over the Internet. It enables the dynamic adaptation of video quality by splitting the video clip into small segments and providing multiple quality levels per segment. Current HAS streaming services typically utilize segments of equal durations. However, this leads to video encoding overhead as segments have to start with I-frames, independently of the encoded video content. In this paper we evaluate the prospects of variable segment durations, where video segments are aligned to the video characteristics. We evaluate the reduction of the encoding overhead and investigate its impact on the stalling probability using a theoretical model. It turns out that the variable approach outperforms the fixed approach in 86% of the evaluated cases with respect to video stalls.

  @inproceedings{info3-inproceedings-2018-12, abstract = {HTTP Adaptive Streaming (HAS) is the de-facto standard for video delivery over the Internet. It enables the dynamic adaptation of video quality by splitting the video clip into small segments and providing multiple quality levels per segment. Current HAS streaming services typically utilize segments of equal durations. However, this leads to video encoding overhead as segments have to start with I-frames, independently of the encoded video content. In this paper we evaluate the prospects of variable segment durations, where video segments are aligned to the video characteristics. We evaluate the reduction of the encoding overhead and investigate its impact on the stalling probability using a theoretical model. It turns out that the variable approach outperforms the fixed approach in 86% of the evaluated cases with respect to video stalls.}, address = {Sardinia, Italy}, author = {Schwarzmann, Susanna and Zinner, Thomas and Sieber, Christian and Geissler, Stefan}, booktitle = {The 2nd International Workshop on Quality of Experience Management}, keywords = {dfg-sdn}, month = {05}, title = {Evaluation of the Benefits of Variable Segment Durations for Adaptive Streaming}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-12 %A Schwarzmann, Susanna %A Zinner, Thomas %A Sieber, Christian %A Geissler, Stefan %B The 2nd International Workshop on Quality of Experience Management %C Sardinia, Italy %D 2018 %T Evaluation of the Benefits of Variable Segment Durations for Adaptive Streaming %X HTTP Adaptive Streaming (HAS) is the de-facto standard for video delivery over the Internet. It enables the dynamic adaptation of video quality by splitting the video clip into small segments and providing multiple quality levels per segment. Current HAS streaming services typically utilize segments of equal durations. However, this leads to video encoding overhead as segments have to start with I-frames, independently of the encoded video content. In this paper we evaluate the prospects of variable segment durations, where video segments are aligned to the video characteristics. We evaluate the reduction of the encoding overhead and investigate its impact on the stalling probability using a theoretical model. It turns out that the variable approach outperforms the fixed approach in 86% of the evaluated cases with respect to video stalls.
• Speed Index: Relating the Industrial Standard for User Perceived Web Performance to Web QoE. Hoßfeld, Tobias; Metzger, Florian; Rossi, Dario. In Proceedings of the 10th International Conference on Quality of Multimedia Experience (QoMEX 2018). Sardinia, Italy, 2018.
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  • [ EndNote ]
  @inproceedings{info3-inproceedings-2018-9, address = {Sardinia, Italy}, author = {Hoßfeld, Tobias and Metzger, Florian and Rossi, Dario}, booktitle = {Proceedings of the 10th International Conference on Quality of Multimedia Experience (QoMEX 2018)}, keywords = {fullstack}, month = {05}, title = {Speed Index: Relating the Industrial Standard for User Perceived Web Performance to Web QoE}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-9 %A Hoßfeld, Tobias %A Metzger, Florian %A Rossi, Dario %B Proceedings of the 10th International Conference on Quality of Multimedia Experience (QoMEX 2018) %C Sardinia, Italy %D 2018 %T Speed Index: Relating the Industrial Standard for User Perceived Web Performance to Web QoE
• A Wrapper for Automatic Measurements with YouTube’s Native Android App. Seufert, Michael; Zeidler, Bernd; Wamser, Florian; Karagkioules, Theodoros; Tsilimantos, Dimitrios; Loh, Frank; Tran-Gia, Phuoc; Valentin, Stefan. In Network Traffic Measurement and Analysis Conference (TMA). Vienna, Austria, 2018.
  • [ Abstract ]
  • [ BibTeX ]
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  YouTube is one of the most popular and demanding services in the Internet today. Thereby, a large portion of this traffic is generated by YouTube's mobile app. While past studies have shown how to monitor browser-based streaming on desktop PCs (e.g., YoMo) or mobile devices (e.g., YoMoApp), streaming in the native app has not been monitored yet. This paper presents an automated framework for monitoring the streaming in YouTube's native app for Android. The concept is based on a wrapper application and the Android Debug Bridge (adb), and can be also extended to automatic measurements with other apps. For YouTube, it allows to collect application-layer streaming data, such as current playtime, buffered playtime, video encoding, and quality switches. These data can be complemented with network measurements on the mobile access link to obtain a holistic view on mobile YouTube streaming on Android devices. In addition to describing the software design and testbed setup, this paper discusses an experimental measurement. This study analyzes the streaming in the native YouTube app and compares it to the streaming from the mobile YouTube website via YoMoApp.

  @inproceedings{info3-article-2018-4, abstract = {YouTube is one of the most popular and demanding services in the Internet today. Thereby, a large portion of this traffic is generated by YouTube's mobile app. While past studies have shown how to monitor browser-based streaming on desktop PCs (e.g., YoMo) or mobile devices (e.g., YoMoApp), streaming in the native app has not been monitored yet. This paper presents an automated framework for monitoring the streaming in YouTube's native app for Android. The concept is based on a wrapper application and the Android Debug Bridge (adb), and can be also extended to automatic measurements with other apps. For YouTube, it allows to collect application-layer streaming data, such as current playtime, buffered playtime, video encoding, and quality switches. These data can be complemented with network measurements on the mobile access link to obtain a holistic view on mobile YouTube streaming on Android devices. In addition to describing the software design and testbed setup, this paper discusses an experimental measurement. This study analyzes the streaming in the native YouTube app and compares it to the streaming from the mobile YouTube website via YoMoApp.}, address = {Vienna, Austria}, author = {Seufert, Michael and Zeidler, Bernd and Wamser, Florian and Karagkioules, Theodoros and Tsilimantos, Dimitrios and Loh, Frank and Tran-Gia, Phuoc and Valentin, Stefan}, booktitle = {Network Traffic Measurement and Analysis Conference (TMA)}, keywords = {can}, month = {04}, title = {A Wrapper for Automatic Measurements with YouTube's Native Android App}, year = 2018 }

  %0 Conference Paper %1 info3-article-2018-4 %A Seufert, Michael %A Zeidler, Bernd %A Wamser, Florian %A Karagkioules, Theodoros %A Tsilimantos, Dimitrios %A Loh, Frank %A Tran-Gia, Phuoc %A Valentin, Stefan %B Network Traffic Measurement and Analysis Conference (TMA) %C Vienna, Austria %D 2018 %T A Wrapper for Automatic Measurements with YouTube's Native Android App %X YouTube is one of the most popular and demanding services in the Internet today. Thereby, a large portion of this traffic is generated by YouTube's mobile app. While past studies have shown how to monitor browser-based streaming on desktop PCs (e.g., YoMo) or mobile devices (e.g., YoMoApp), streaming in the native app has not been monitored yet. This paper presents an automated framework for monitoring the streaming in YouTube's native app for Android. The concept is based on a wrapper application and the Android Debug Bridge (adb), and can be also extended to automatic measurements with other apps. For YouTube, it allows to collect application-layer streaming data, such as current playtime, buffered playtime, video encoding, and quality switches. These data can be complemented with network measurements on the mobile access link to obtain a holistic view on mobile YouTube streaming on Android devices. In addition to describing the software design and testbed setup, this paper discusses an experimental measurement. This study analyzes the streaming in the native YouTube app and compares it to the streaming from the mobile YouTube website via YoMoApp.
• Quality of Experience and Access Network Traffic Management of HTTP Adaptive Video Streaming. Seufert, Michael; Tran-Gia, Phuoc. In IEEE/IFIP Network Operations and Management Symposium (NOMS), Best Dissertation Award. Taipei, Taiwan, 2018.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  The thesis focuses on Quality of Experience (QoE) of HTTP adaptive video streaming (HAS) and traffic management in access networks to improve the QoE of HAS. First, the QoE impact of adaptation parameters and time on layer was investigated with subjective crowdsourcing studies. The results were used to compute a QoE-optimal adaptation strategy for given video and network conditions. This allows video service providers to develop and benchmark improved adaptation logics for HAS. Furthermore, the thesis investigated concepts to monitor video QoE on application and network layer, which can be used by network providers in the QoE-aware traffic management cycle. Moreover, an analytic and simulative performance evaluation of QoE-aware traffic management on a bottleneck link was conducted. Finally, the thesis investigated socially-aware traffic management for HAS via Wi-Fi offloading of mobile HAS flows. A model for the distribution of public Wi-Fi hotspots and a platform for socially-aware traffic management on private home routers was presented. A simulative performance evaluation investigated the impact of Wi-Fi offloading on the QoE and energy consumption of mobile HAS.

  @inproceedings{info3-inproceedings-2018-42, abstract = {The thesis focuses on Quality of Experience (QoE) of HTTP adaptive video streaming (HAS) and traffic management in access networks to improve the QoE of HAS. First, the QoE impact of adaptation parameters and time on layer was investigated with subjective crowdsourcing studies. The results were used to compute a QoE-optimal adaptation strategy for given video and network conditions. This allows video service providers to develop and benchmark improved adaptation logics for HAS. Furthermore, the thesis investigated concepts to monitor video QoE on application and network layer, which can be used by network providers in the QoE-aware traffic management cycle. Moreover, an analytic and simulative performance evaluation of QoE-aware traffic management on a bottleneck link was conducted. Finally, the thesis investigated socially-aware traffic management for HAS via Wi-Fi offloading of mobile HAS flows. A model for the distribution of public Wi-Fi hotspots and a platform for socially-aware traffic management on private home routers was presented. A simulative performance evaluation investigated the impact of Wi-Fi offloading on the QoE and energy consumption of mobile HAS.}, address = {Taipei, Taiwan}, author = {Seufert, Michael and Tran-Gia, Phuoc}, booktitle = {IEEE/IFIP Network Operations and Management Symposium (NOMS), Best Dissertation Award}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Quality of Experience and Access Network Traffic Management of HTTP Adaptive Video Streaming}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-42 %A Seufert, Michael %A Tran-Gia, Phuoc %B IEEE/IFIP Network Operations and Management Symposium (NOMS), Best Dissertation Award %C Taipei, Taiwan %D 2018 %T Quality of Experience and Access Network Traffic Management of HTTP Adaptive Video Streaming %X The thesis focuses on Quality of Experience (QoE) of HTTP adaptive video streaming (HAS) and traffic management in access networks to improve the QoE of HAS. First, the QoE impact of adaptation parameters and time on layer was investigated with subjective crowdsourcing studies. The results were used to compute a QoE-optimal adaptation strategy for given video and network conditions. This allows video service providers to develop and benchmark improved adaptation logics for HAS. Furthermore, the thesis investigated concepts to monitor video QoE on application and network layer, which can be used by network providers in the QoE-aware traffic management cycle. Moreover, an analytic and simulative performance evaluation of QoE-aware traffic management on a bottleneck link was conducted. Finally, the thesis investigated socially-aware traffic management for HAS via Wi-Fi offloading of mobile HAS flows. A model for the distribution of public Wi-Fi hotspots and a platform for socially-aware traffic management on private home routers was presented. A simulative performance evaluation investigated the impact of Wi-Fi offloading on the QoE and energy consumption of mobile HAS.
• Integrating Network Management Information into the SDN Control Plane. Lange, Stanislav; Reinhart, Lorenz; Zinner, Thomas; Hock, David; Gray, Nicholas; Tran-Gia, Phuoc. In IEEE/IFIP Network Operations and Management Symposium (NOMS). 2018.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  With software defined networking (SDN), operators benefit from a higher flexibility, cost efficiency, as well as programmability of their networks. Since modern networks are comprised of a multitude of heterogeneous devices and also include non-SDN legacy devices, network management systems (NMSs) are often used in order to monitor and configure the network. Although both, the SDN controller and the NMS, have a centralized view of the network, they operate at different time scales and deal with information at different levels of granularity. In this work, we investigate the impact on the network performance when an NMS regularly provides information to an SDN controller. To this end, we design, implement, and compare three interaction mechanisms based on the ONOS controller. These represent different trade-offs regarding the complexity of the resulting system and its performance. In addition to the default ONOS controller, we develop two extended versions. One performs hash-based load balancing on equal cost paths while the other utilizes external NMS information via ONOS's intent and annotation framework to optimize control plane decisions. In addition to evaluations that show a significant performance improvement when using the optimized controllers, we present a parameter study that highlights the performance impact of network characteristics like the flow interarrival time, the flow duration, and the number of active flows.

  @inproceedings{info3-inproceedings-2018-10, abstract = {With software defined networking (SDN), operators benefit from a higher flexibility, cost efficiency, as well as programmability of their networks. Since modern networks are comprised of a multitude of heterogeneous devices and also include non-SDN legacy devices, network management systems (NMSs) are often used in order to monitor and configure the network. Although both, the SDN controller and the NMS, have a centralized view of the network, they operate at different time scales and deal with information at different levels of granularity. In this work, we investigate the impact on the network performance when an NMS regularly provides information to an SDN controller. To this end, we design, implement, and compare three interaction mechanisms based on the ONOS controller. These represent different trade-offs regarding the complexity of the resulting system and its performance. In addition to the default ONOS controller, we develop two extended versions. One performs hash-based load balancing on equal cost paths while the other utilizes external NMS information via ONOS's intent and annotation framework to optimize control plane decisions. In addition to evaluations that show a significant performance improvement when using the optimized controllers, we present a parameter study that highlights the performance impact of network characteristics like the flow interarrival time, the flow duration, and the number of active flows.}, author = {Lange, Stanislav and Reinhart, Lorenz and Zinner, Thomas and Hock, David and Gray, Nicholas and Tran-Gia, Phuoc}, booktitle = {IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {sdnperf}, month = {04}, title = {Integrating Network Management Information into the SDN Control Plane}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-10 %A Lange, Stanislav %A Reinhart, Lorenz %A Zinner, Thomas %A Hock, David %A Gray, Nicholas %A Tran-Gia, Phuoc %B IEEE/IFIP Network Operations and Management Symposium (NOMS) %D 2018 %T Integrating Network Management Information into the SDN Control Plane %X With software defined networking (SDN), operators benefit from a higher flexibility, cost efficiency, as well as programmability of their networks. Since modern networks are comprised of a multitude of heterogeneous devices and also include non-SDN legacy devices, network management systems (NMSs) are often used in order to monitor and configure the network. Although both, the SDN controller and the NMS, have a centralized view of the network, they operate at different time scales and deal with information at different levels of granularity. In this work, we investigate the impact on the network performance when an NMS regularly provides information to an SDN controller. To this end, we design, implement, and compare three interaction mechanisms based on the ONOS controller. These represent different trade-offs regarding the complexity of the resulting system and its performance. In addition to the default ONOS controller, we develop two extended versions. One performs hash-based load balancing on equal cost paths while the other utilizes external NMS information via ONOS's intent and annotation framework to optimize control plane decisions. In addition to evaluations that show a significant performance improvement when using the optimized controllers, we present a parameter study that highlights the performance impact of network characteristics like the flow interarrival time, the flow duration, and the number of active flows.
• Observations on Emerging Aspects in QoE Modeling and Their Impact on QoE Management. Hoßfeld, Tobias; Varela, Martin; Heegaard, Poul E.; Skorin-Kapov, Lea. In 2018 Tenth International Conference on Quality of Multimedia Experience (QoMEX). 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2018-50, author = {Hoßfeld, Tobias and Varela, Martin and Heegaard, Poul E. and Skorin-Kapov, Lea}, booktitle = {2018 Tenth International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, title = {Observations on Emerging Aspects in QoE Modeling and Their Impact on QoE Management}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-50 %A Hoßfeld, Tobias %A Varela, Martin %A Heegaard, Poul E. %A Skorin-Kapov, Lea %B 2018 Tenth International Conference on Quality of Multimedia Experience (QoMEX) %D 2018 %T Observations on Emerging Aspects in QoE Modeling and Their Impact on QoE Management
• Performance Evaluation of Mobile Crowdsensing for Event Detection. Hirth, Matthias; Lange, Stanislav; Seufert, Michael; Tran-Gia, Phuoc. In Proceedings of the 5th International Workshop on Crowd Assisted Sensing, Pervasive Systems and Communications. Athens, Greece, 2018.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Crowdsensing offers a cost effective way to collect large amounts of sensor data. However, in contrast to fixed sensor deployments, the spatial distribution of the sensors can hardly be influence, as the sensors are carried by participants of the crowdsensing system. This in turn raises the question about the performance of such systems with respect to the detection probability and detection time of spatial events. In order to address this question, we analyze the performance of such a crowdsensing system by means of simulation. We use the traffic infrastructure of a small size city in Germany and simulate the inhabitants’ movement patterns with the well established SUMO mobility generator. Our results show that even if only a small share of inhabitants participates in crowdsensing, events, which have locations that are correlated with the population density, can be easily and quickly detected using such a system. On the contrary, events whose locations are uniformly randomly distributed are much harder to detect using a crowdsensing approach.

  @inproceedings{info3-inproceedings-2017-21, abstract = {Crowdsensing offers a cost effective way to collect large amounts of sensor data. However, in contrast to fixed sensor deployments, the spatial distribution of the sensors can hardly be influence, as the sensors are carried by participants of the crowdsensing system. This in turn raises the question about the performance of such systems with respect to the detection probability and detection time of spatial events. In order to address this question, we analyze the performance of such a crowdsensing system by means of simulation. We use the traffic infrastructure of a small size city in Germany and simulate the inhabitants’ movement patterns with the well established SUMO mobility generator. Our results show that even if only a small share of inhabitants participates in crowdsensing, events, which have locations that are correlated with the population density, can be easily and quickly detected using such a system. On the contrary, events whose locations are uniformly randomly distributed are much harder to detect using a crowdsensing approach.}, address = {Athens, Greece}, author = {Hirth, Matthias and Lange, Stanislav and Seufert, Michael and Tran-Gia, Phuoc}, booktitle = {Proceedings of the 5th International Workshop on Crowd Assisted Sensing, Pervasive Systems and Communications}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Performance Evaluation of Mobile Crowdsensing for Event Detection}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2017-21 %A Hirth, Matthias %A Lange, Stanislav %A Seufert, Michael %A Tran-Gia, Phuoc %B Proceedings of the 5th International Workshop on Crowd Assisted Sensing, Pervasive Systems and Communications %C Athens, Greece %D 2018 %T Performance Evaluation of Mobile Crowdsensing for Event Detection %X Crowdsensing offers a cost effective way to collect large amounts of sensor data. However, in contrast to fixed sensor deployments, the spatial distribution of the sensors can hardly be influence, as the sensors are carried by participants of the crowdsensing system. This in turn raises the question about the performance of such systems with respect to the detection probability and detection time of spatial events. In order to address this question, we analyze the performance of such a crowdsensing system by means of simulation. We use the traffic infrastructure of a small size city in Germany and simulate the inhabitants’ movement patterns with the well established SUMO mobility generator. Our results show that even if only a small share of inhabitants participates in crowdsensing, events, which have locations that are correlated with the population density, can be easily and quickly detected using such a system. On the contrary, events whose locations are uniformly randomly distributed are much harder to detect using a crowdsensing approach.
• Practical QoE Evaluation of Adaptive Video Streaming. Surminski, Sebastian; Moldovan, Christian; Hoßfeld, Tobias. In Proceedings of the 19th International Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB). Erlangen, Germany, 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2018-7, address = {Erlangen, Germany}, author = {Surminski, Sebastian and Moldovan, Christian and Hoßfeld, Tobias}, booktitle = {Proceedings of the 19th International Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB)}, keywords = {dfg-sdn}, month = {02}, title = {Practical QoE Evaluation of Adaptive Video Streaming}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-7 %A Surminski, Sebastian %A Moldovan, Christian %A Hoßfeld, Tobias %B Proceedings of the 19th International Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB) %C Erlangen, Germany %D 2018 %T Practical QoE Evaluation of Adaptive Video Streaming
• Estimating the Flow Rule Installation Time of SDN Switches when Facing Control Plane Delay. Nguyen-Ngoc, Anh; Lange, Stanislav; Geissler, Stefan; Zinner, Thomas; Tran-Gia, Phuoc. In 19th International GI/ITG Conference on “Measurement, Modelling and Evaluation of Computing Systems”. Erlangen, 2018.
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  The software defined networking (SDN) paradigm has numerous benefits for network operators, including cost aspects, flexibility, and programmability. In the centralized SDN architecture, the controller can order the installation of flow rules in the switches it manages via FlowMod messages. Since the processing time of these messages has a direct impact on the reaction time of the network, it is a key performance indicator for switches and quantifying it in a reliable manner is required for ensuring state consistency between the control and the data plane. Furthermore, real world deployments not only consist of different data plane hardware, but may feature varying control plane delays. Hence, in this work, we investigate the impact of such a delay on the FlowMod processing time of OpenFlow switches. Firstly, we identify a significant heterogeneity between data plane hardware in terms of processing times as well as the underlying TCP-level behavior. Secondly, we show that despite this heterogeneity, combining switch specific information with delay measurements at the controller can be used to reliably infer FlowMod processing times. We confirm our results with measurements in a dedicated testbed that is comprised of three different hardware switches, three different SDN controllers, and several high precision measurement devices.

  @inproceedings{info3-inproceedings-2018-4, abstract = {The software defined networking (SDN) paradigm has numerous benefits for network operators, including cost aspects, flexibility, and programmability. In the centralized SDN architecture, the controller can order the installation of flow rules in the switches it manages via FlowMod messages. Since the processing time of these messages has a direct impact on the reaction time of the network, it is a key performance indicator for switches and quantifying it in a reliable manner is required for ensuring state consistency between the control and the data plane. Furthermore, real world deployments not only consist of different data plane hardware, but may feature varying control plane delays. Hence, in this work, we investigate the impact of such a delay on the FlowMod processing time of OpenFlow switches. Firstly, we identify a significant heterogeneity between data plane hardware in terms of processing times as well as the underlying TCP-level behavior. Secondly, we show that despite this heterogeneity, combining switch specific information with delay measurements at the controller can be used to reliably infer FlowMod processing times. We confirm our results with measurements in a dedicated testbed that is comprised of three different hardware switches, three different SDN controllers, and several high precision measurement devices.}, address = {Erlangen}, author = {Nguyen-Ngoc, Anh and Lange, Stanislav and Geissler, Stefan and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {19th International GI/ITG Conference on “Measurement, Modelling and Evaluation of Computing Systems”}, keywords = {sendate}, month = {02}, title = {Estimating the Flow Rule Installation Time of SDN Switches when Facing Control Plane Delay}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-4 %A Nguyen-Ngoc, Anh %A Lange, Stanislav %A Geissler, Stefan %A Zinner, Thomas %A Tran-Gia, Phuoc %B 19th International GI/ITG Conference on “Measurement, Modelling and Evaluation of Computing Systems” %C Erlangen %D 2018 %T Estimating the Flow Rule Installation Time of SDN Switches when Facing Control Plane Delay %X The software defined networking (SDN) paradigm has numerous benefits for network operators, including cost aspects, flexibility, and programmability. In the centralized SDN architecture, the controller can order the installation of flow rules in the switches it manages via FlowMod messages. Since the processing time of these messages has a direct impact on the reaction time of the network, it is a key performance indicator for switches and quantifying it in a reliable manner is required for ensuring state consistency between the control and the data plane. Furthermore, real world deployments not only consist of different data plane hardware, but may feature varying control plane delays. Hence, in this work, we investigate the impact of such a delay on the FlowMod processing time of OpenFlow switches. Firstly, we identify a significant heterogeneity between data plane hardware in terms of processing times as well as the underlying TCP-level behavior. Secondly, we show that despite this heterogeneity, combining switch specific information with delay measurements at the controller can be used to reliably infer FlowMod processing times. We confirm our results with measurements in a dedicated testbed that is comprised of three different hardware switches, three different SDN controllers, and several high precision measurement devices.
• Traffic Modeling for Aggregated Periodic IoT Data. Hoßfeld, Tobias; Metzger, Florian; Heegaard, Poul E. In Proceedings of the 21st Conference on Innovation in Clouds, Internet and Networks (ICIN). Paris, France, 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2018-6, address = {Paris, France}, author = {Hoßfeld, Tobias and Metzger, Florian and Heegaard, Poul E.}, booktitle = {Proceedings of the 21st Conference on Innovation in Clouds, Internet and Networks (ICIN)}, keywords = {fullstack}, month = {02}, title = {Traffic Modeling for Aggregated Periodic IoT Data}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-6 %A Hoßfeld, Tobias %A Metzger, Florian %A Heegaard, Poul E. %B Proceedings of the 21st Conference on Innovation in Clouds, Internet and Networks (ICIN) %C Paris, France %D 2018 %T Traffic Modeling for Aggregated Periodic IoT Data
• QoE Analysis of the Setup of Different Internet Services for FIFO Server Systems. Hoßfeld, Tobias; Varela, Martin; Heegaard, Poul E.; Skorin-Kapov, Lea. In Proceedings of the 19th International Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB). Erlangen, Germany, 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2018-8, address = {Erlangen, Germany}, author = {Hoßfeld, Tobias and Varela, Martin and Heegaard, Poul E. and Skorin-Kapov, Lea}, booktitle = {Proceedings of the 19th International Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB)}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {QoE Analysis of the Setup of Different Internet Services for FIFO Server Systems}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-8 %A Hoßfeld, Tobias %A Varela, Martin %A Heegaard, Poul E. %A Skorin-Kapov, Lea %B Proceedings of the 19th International Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB) %C Erlangen, Germany %D 2018 %T QoE Analysis of the Setup of Different Internet Services for FIFO Server Systems
• A Public Dataset for YouTube’s Mobile Streaming Client. Karagkioules, Theodoros; Tsilimantos, Dimitrios; Valentin, Stefan; Wamser, Florian; Zeidler, Bernd; Seufert, Michael; Loh, Frank; Tran-Gia, Phuoc. In Network Traffic Measurement and Analysis Conference (TMA). Vienna, Austria, 2018.
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  @inproceedings{info3-inproceedings-2018-41, address = {Vienna, Austria}, author = {Karagkioules, Theodoros and Tsilimantos, Dimitrios and Valentin, Stefan and Wamser, Florian and Zeidler, Bernd and Seufert, Michael and Loh, Frank and Tran-Gia, Phuoc}, booktitle = {Network Traffic Measurement and Analysis Conference (TMA)}, keywords = {can}, title = {A Public Dataset for YouTube’s Mobile Streaming Client}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-41 %A Karagkioules, Theodoros %A Tsilimantos, Dimitrios %A Valentin, Stefan %A Wamser, Florian %A Zeidler, Bernd %A Seufert, Michael %A Loh, Frank %A Tran-Gia, Phuoc %B Network Traffic Measurement and Analysis Conference (TMA) %C Vienna, Austria %D 2018 %T A Public Dataset for YouTube’s Mobile Streaming Client
• How do crowdworker communities and microtask markets influenceeach other? A data-driven study on Amazon Mechanical Turk. Yang, Jie; van der Valk, Carlo; Hoßfeld, Tobias; Redi, Judith; Bozzon, Alessandro. In Sixth AAAI Conference on Human Computation and Crowdsourcing. 2018.
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  • [ EndNote ]
  @inproceedings{info3-techreport-2018-1, author = {Yang, Jie and van der Valk, Carlo and Hoßfeld, Tobias and Redi, Judith and Bozzon, Alessandro}, booktitle = {Sixth AAAI Conference on Human Computation and Crowdsourcing}, keywords = {sys:hidden:inproceedings}, title = {How do crowdworker communities and microtask markets influenceeach other? A data-driven study on Amazon Mechanical Turk}, year = 2018 }

  %0 Conference Paper %1 info3-techreport-2018-1 %A Yang, Jie %A van der Valk, Carlo %A Hoßfeld, Tobias %A Redi, Judith %A Bozzon, Alessandro %B Sixth AAAI Conference on Human Computation and Crowdsourcing %D 2018 %T How do crowdworker communities and microtask markets influenceeach other? A data-driven study on Amazon Mechanical Turk
• User Experience of Web Browsing-The Relationship of Usability and Quality of Experience. Voigt-Antons, Jan-Niklas; Hoßfeld, Tobias; Egger-Lampl, Sebastian; Schatz, Raimund; Möller, Sebastian. In Tenth International Conference on Quality of Multimedia Experience (QoMEX). 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2018-48, author = {Voigt-Antons, Jan-Niklas and Hoßfeld, Tobias and Egger-Lampl, Sebastian and Schatz, Raimund and Möller, Sebastian}, booktitle = {Tenth International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {User Experience of Web Browsing-The Relationship of Usability and Quality of Experience}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-48 %A Voigt-Antons, Jan-Niklas %A Hoßfeld, Tobias %A Egger-Lampl, Sebastian %A Schatz, Raimund %A Möller, Sebastian %B Tenth International Conference on Quality of Multimedia Experience (QoMEX) %D 2018 %T User Experience of Web Browsing-The Relationship of Usability and Quality of Experience
• A Cumulative Quality Model for HTTP Adaptive Streaming. Tran, Huyen TT; Pham Ngoc, Nam; Hoßfeld, Tobias; Thang, Truong Cong. In Tenth International Conference on Quality of Multimedia Experience (QoMEX). 2018.
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  @inproceedings{info3-inproceedings-2018-47, author = {Tran, Huyen TT and Pham Ngoc, Nam and Hoßfeld, Tobias and Thang, Truong Cong}, booktitle = {Tenth International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {A Cumulative Quality Model for HTTP Adaptive Streaming}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-47 %A Tran, Huyen TT %A Pham Ngoc, Nam %A Hoßfeld, Tobias %A Thang, Truong Cong %B Tenth International Conference on Quality of Multimedia Experience (QoMEX) %D 2018 %T A Cumulative Quality Model for HTTP Adaptive Streaming
• Performance Benchmarking of Network Function Chain Placement Algorithms. Grigorjew, Alexej; Lange, Stanislav; Zinner, Thomas; Tran-Gia, Phuoc. In 19th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB). 2018.
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  @inproceedings{info3-inproceedings-2018-1, author = {Grigorjew, Alexej and Lange, Stanislav and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {19th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB)}, keywords = {sendate}, month = {02}, title = {Performance Benchmarking of Network Function Chain Placement Algorithms}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-1 %A Grigorjew, Alexej %A Lange, Stanislav %A Zinner, Thomas %A Tran-Gia, Phuoc %B 19th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB) %D 2018 %T Performance Benchmarking of Network Function Chain Placement Algorithms
• Orchestration and Monitoring in Fog Computing for Personal Edge Cloud Service Support. Wamser, Florian; Lombardo, Chiara; Vassilakis, Constantinos; Dinh-Xuan, Lam; Lago, Paolo; Bruschi, Roberto; Tran-Gia, Phuoc. In 2018 IEEE International Symposium on Local and Metropolitan Area Networks (LANMAN). 2018.
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  @inproceedings{info3-inproceedings-2018-30, author = {Wamser, Florian and Lombardo, Chiara and Vassilakis, Constantinos and Dinh-Xuan, Lam and Lago, Paolo and Bruschi, Roberto and Tran-Gia, Phuoc}, booktitle = {2018 IEEE International Symposium on Local and Metropolitan Area Networks (LANMAN)}, keywords = {can}, month = {06}, title = {Orchestration and Monitoring in Fog Computing for Personal Edge Cloud Service Support}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-30 %A Wamser, Florian %A Lombardo, Chiara %A Vassilakis, Constantinos %A Dinh-Xuan, Lam %A Lago, Paolo %A Bruschi, Roberto %A Tran-Gia, Phuoc %B 2018 IEEE International Symposium on Local and Metropolitan Area Networks (LANMAN) %D 2018 %T Orchestration and Monitoring in Fog Computing for Personal Edge Cloud Service Support
• Optimal Fairness and Quality in Video Streaming With Multiple Users. Moldovan, Christian; Skorin-Kapov, Lea; Heegaard, Poul E.; Hoßfeld, Tobias. In 30th International Teletraffic Congress (ITC 30), p. 6. Vienna, Austria, 2018.
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  With the majority of video distribution services relying on the HTTP adaptive streaming paradigm, a great deal of research is geared towards developing algorithms and solutions for improving user perceived quality while making efficient use of available resources. Our goal is to provide the means for benchmarking such solutions in the context of multiple users accessing Video on Demand content while sharing a bottleneck link. For that purpose, we propose a quadratic problem formulation to compute the theoretical optimum in terms of adaptation strategies and corresponding segment downloads across multiple users under given bandwidth constraints. By aiming to maximize both service quality and fairness, we quantify and compare the impact of different fairness objectives (bandwidth fairness, pattern fairness, and session fairness) on resulting quality and achieved QoE fairness. Based on conducted simulations and parameter studies, our results demonstrate the benefits of optimizing for session fairness as compared to other approaches.

  @inproceedings{info3-inproceedings-2018-37, abstract = {With the majority of video distribution services relying on the HTTP adaptive streaming paradigm, a great deal of research is geared towards developing algorithms and solutions for improving user perceived quality while making efficient use of available resources. Our goal is to provide the means for benchmarking such solutions in the context of multiple users accessing Video on Demand content while sharing a bottleneck link. For that purpose, we propose a quadratic problem formulation to compute the theoretical optimum in terms of adaptation strategies and corresponding segment downloads across multiple users under given bandwidth constraints. By aiming to maximize both service quality and fairness, we quantify and compare the impact of different fairness objectives (bandwidth fairness, pattern fairness, and session fairness) on resulting quality and achieved QoE fairness. Based on conducted simulations and parameter studies, our results demonstrate the benefits of optimizing for session fairness as compared to other approaches.}, address = {Vienna, Austria}, author = {Moldovan, Christian and Skorin-Kapov, Lea and Heegaard, Poul E. and Hoßfeld, Tobias}, booktitle = {30th International Teletraffic Congress (ITC 30)}, keywords = {video-quality}, month = {09}, pages = 6, title = {Optimal Fairness and Quality in Video Streaming With Multiple Users}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-37 %A Moldovan, Christian %A Skorin-Kapov, Lea %A Heegaard, Poul E. %A Hoßfeld, Tobias %B 30th International Teletraffic Congress (ITC 30) %C Vienna, Austria %D 2018 %P 6 %T Optimal Fairness and Quality in Video Streaming With Multiple Users %X With the majority of video distribution services relying on the HTTP adaptive streaming paradigm, a great deal of research is geared towards developing algorithms and solutions for improving user perceived quality while making efficient use of available resources. Our goal is to provide the means for benchmarking such solutions in the context of multiple users accessing Video on Demand content while sharing a bottleneck link. For that purpose, we propose a quadratic problem formulation to compute the theoretical optimum in terms of adaptation strategies and corresponding segment downloads across multiple users under given bandwidth constraints. By aiming to maximize both service quality and fairness, we quantify and compare the impact of different fairness objectives (bandwidth fairness, pattern fairness, and session fairness) on resulting quality and achieved QoE fairness. Based on conducted simulations and parameter studies, our results demonstrate the benefits of optimizing for session fairness as compared to other approaches.
• Evaluation of the Detection Capabilities of the ONOS SDN Controller. Metter, Christopher; Burger, Valentin; Hu, Zheng; Pei, Ke; Wamser, Florian. In 7th IEEE International Conference on Communications and Electronics (IEEE ICCE 2018), pp. 96–101. Hue, Vietnam, 2018.
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  The process of monitoring the network, especially for larger ones, is very complex and contains many pitfalls. For instance the balance between granularity of information and their performance impact on the network. With the help of SDN this challenge can become easier, as it offers new methods, mechanisms and opportunities. One of the current most important Open Source controllers is the ONOS SDN controller. According to its developers it is a production ready controller that offers high availability due to its logically centralized and physically distributed architecture. But, as our investigations show, it is unable to cope with hazardous network conditions such as sporadic or recurring packet loss. It either does not detect packet loss or only detects it after long time periods, failing all common network availability targets.

  @inproceedings{info3-inproceedings-2018-22, abstract = {The process of monitoring the network, especially for larger ones, is very complex and contains many pitfalls. For instance the balance between granularity of information and their performance impact on the network. With the help of SDN this challenge can become easier, as it offers new methods, mechanisms and opportunities. One of the current most important Open Source controllers is the ONOS SDN controller. According to its developers it is a production ready controller that offers high availability due to its logically centralized and physically distributed architecture. But, as our investigations show, it is unable to cope with hazardous network conditions such as sporadic or recurring packet loss. It either does not detect packet loss or only detects it after long time periods, failing all common network availability targets.}, address = {Hue, Vietnam}, author = {Metter, Christopher and Burger, Valentin and Hu, Zheng and Pei, Ke and Wamser, Florian}, booktitle = {7th IEEE International Conference on Communications and Electronics (IEEE ICCE 2018)}, keywords = {can}, month = {07}, pages = {96 - 101}, title = {Evaluation of the Detection Capabilities of the ONOS SDN Controller}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-22 %A Metter, Christopher %A Burger, Valentin %A Hu, Zheng %A Pei, Ke %A Wamser, Florian %B 7th IEEE International Conference on Communications and Electronics (IEEE ICCE 2018) %C Hue, Vietnam %D 2018 %P 96 - 101 %T Evaluation of the Detection Capabilities of the ONOS SDN Controller %X The process of monitoring the network, especially for larger ones, is very complex and contains many pitfalls. For instance the balance between granularity of information and their performance impact on the network. With the help of SDN this challenge can become easier, as it offers new methods, mechanisms and opportunities. One of the current most important Open Source controllers is the ONOS SDN controller. According to its developers it is a production ready controller that offers high availability due to its logically centralized and physically distributed architecture. But, as our investigations show, it is unable to cope with hazardous network conditions such as sporadic or recurring packet loss. It either does not detect packet loss or only detects it after long time periods, failing all common network availability targets.
• A Fair Share for All: Novel Adaptation Logic for QoE Fairness of HTTP Adaptive Video Streaming. Seufert, Michael; Wehner, Nikolas; Casas, Pedro; Wamser, Florian. In 14th International Conference on Network and Service Management (CNSM), Best Paper Award. Rome, Italy, 2018.
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  This paper presents a novel adaptation logic for HTTP adaptive streaming (HAS), which achieves not only a high Quality of Experience (QoE) but also high QoE fairness among independent and heterogeneous clients. The algorithm forces video clients to adapt the requested quality level based on the current network conditions and their individual bit rate requirements, such that the overall quality levels selected by all currently active streaming clients are fairly distributed, i.e., they do not diverge too much. The design of the algorithm is inspired by the well-known Transmission Control Protocol (TCP) congestion control, and drives heterogeneous clients to independently converge on similar quality levels without the need for communicating with each other and/or with a centralized controller in the network. By defining quality levels with equal visual quality, and preparing video representations accordingly, the quality level fairness is extended to QoE fairness. In this work, the design of the algorithm is described and a simulative performance evaluation is conducted to compare the QoE and QoE fairness of the proposed algorithm with other HAS adaptation logics.

  @inproceedings{info3-inproceedings-2018-38, abstract = {This paper presents a novel adaptation logic for HTTP adaptive streaming (HAS), which achieves not only a high Quality of Experience (QoE) but also high QoE fairness among independent and heterogeneous clients. The algorithm forces video clients to adapt the requested quality level based on the current network conditions and their individual bit rate requirements, such that the overall quality levels selected by all currently active streaming clients are fairly distributed, i.e., they do not diverge too much. The design of the algorithm is inspired by the well-known Transmission Control Protocol (TCP) congestion control, and drives heterogeneous clients to independently converge on similar quality levels without the need for communicating with each other and/or with a centralized controller in the network. By defining quality levels with equal visual quality, and preparing video representations accordingly, the quality level fairness is extended to QoE fairness. In this work, the design of the algorithm is described and a simulative performance evaluation is conducted to compare the QoE and QoE fairness of the proposed algorithm with other HAS adaptation logics.}, address = {Rome, Italy}, author = {Seufert, Michael and Wehner, Nikolas and Casas, Pedro and Wamser, Florian}, booktitle = {14th International Conference on Network and Service Management (CNSM), Best Paper Award}, keywords = {can}, month = 11, title = {A Fair Share for All: Novel Adaptation Logic for QoE Fairness of HTTP Adaptive Video Streaming}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-38 %A Seufert, Michael %A Wehner, Nikolas %A Casas, Pedro %A Wamser, Florian %B 14th International Conference on Network and Service Management (CNSM), Best Paper Award %C Rome, Italy %D 2018 %T A Fair Share for All: Novel Adaptation Logic for QoE Fairness of HTTP Adaptive Video Streaming %X This paper presents a novel adaptation logic for HTTP adaptive streaming (HAS), which achieves not only a high Quality of Experience (QoE) but also high QoE fairness among independent and heterogeneous clients. The algorithm forces video clients to adapt the requested quality level based on the current network conditions and their individual bit rate requirements, such that the overall quality levels selected by all currently active streaming clients are fairly distributed, i.e., they do not diverge too much. The design of the algorithm is inspired by the well-known Transmission Control Protocol (TCP) congestion control, and drives heterogeneous clients to independently converge on similar quality levels without the need for communicating with each other and/or with a centralized controller in the network. By defining quality levels with equal visual quality, and preparing video representations accordingly, the quality level fairness is extended to QoE fairness. In this work, the design of the algorithm is described and a simulative performance evaluation is conducted to compare the QoE and QoE fairness of the proposed algorithm with other HAS adaptation logics.
• Towards an Active Probing Extension for the {ONOS} {SDN} Controller. Metter, Christopher; Burger, Valentin; Hu, Zheng; Pei, Ke; Wamser, Florian. In 2018 28th International Telecommunication Networks and Applications Conference (ITNAC) (ITNAC 2018), p. 8. Sydney, Australia, 2018.
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  Network monitoring is a complex task and is always a trade-off between granularity of information and the performance impact of the monitoring itself on the network. SDN controllers, such as the ONOS SDN controller make this challenge easier as they can supply centralized information over the whole network. In our previous work we mathematically analyzed the built-in detection mechanism of ONOS and revealed a lack of detection performance and the vulnerability of this process to jitter. These results were also verified by measurements. In this paper we present an Active Probing extension for the ONOS SDN controller that overcomes these shortcomings by emitting probing packets that are transmitted through the network. Statistics over a history of those packets allow for the detection of packet loss. The evaluation by the means of measurements proves the benefits in terms of detection performance and controller load of this application. Furthermore, our extension is able to detect jitter being present in the network and to automatically adapt the probing process to these conditions.

  @inproceedings{info3-inproceedings-2018-34, abstract = {Network monitoring is a complex task and is always a trade-off between granularity of information and the performance impact of the monitoring itself on the network. SDN controllers, such as the ONOS SDN controller make this challenge easier as they can supply centralized information over the whole network. In our previous work we mathematically analyzed the built-in detection mechanism of ONOS and revealed a lack of detection performance and the vulnerability of this process to jitter. These results were also verified by measurements. In this paper we present an Active Probing extension for the ONOS SDN controller that overcomes these shortcomings by emitting probing packets that are transmitted through the network. Statistics over a history of those packets allow for the detection of packet loss. The evaluation by the means of measurements proves the benefits in terms of detection performance and controller load of this application. Furthermore, our extension is able to detect jitter being present in the network and to automatically adapt the probing process to these conditions.}, address = {Sydney, Australia}, author = {Metter, Christopher and Burger, Valentin and Hu, Zheng and Pei, Ke and Wamser, Florian}, booktitle = {2018 28th International Telecommunication Networks and Applications Conference (ITNAC) (ITNAC 2018)}, keywords = {can}, month = 11, pages = 8, title = {Towards an Active Probing Extension for the {ONOS} {SDN} Controller}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-34 %A Metter, Christopher %A Burger, Valentin %A Hu, Zheng %A Pei, Ke %A Wamser, Florian %B 2018 28th International Telecommunication Networks and Applications Conference (ITNAC) (ITNAC 2018) %C Sydney, Australia %D 2018 %P 8 %T Towards an Active Probing Extension for the {ONOS} {SDN} Controller %X Network monitoring is a complex task and is always a trade-off between granularity of information and the performance impact of the monitoring itself on the network. SDN controllers, such as the ONOS SDN controller make this challenge easier as they can supply centralized information over the whole network. In our previous work we mathematically analyzed the built-in detection mechanism of ONOS and revealed a lack of detection performance and the vulnerability of this process to jitter. These results were also verified by measurements. In this paper we present an Active Probing extension for the ONOS SDN controller that overcomes these shortcomings by emitting probing packets that are transmitted through the network. Statistics over a history of those packets allow for the detection of packet loss. The evaluation by the means of measurements proves the benefits in terms of detection performance and controller load of this application. Furthermore, our extension is able to detect jitter being present in the network and to automatically adapt the probing process to these conditions.
• Potential Traffic Savings by Leveraging Proximity of Communication Groups in Mobile Messaging. Seufert, Michael; Schwind, Anika; Waigand, Marco; Hoßfeld, Tobias. In 14th International Conference on Network and Service Management (CNSM). Rome, Italy, 2018.
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  Communication groups in mobile messaging applications (MMAs) multiply the data transmissions, because every message has to be delivered to all members of the communication group. Thereby, they put a high load on mobile networks. As the number of recipients is still comparably small, the dataintensive user-generated content cannot be handled efficiently in large content delivery networks. However, small communication groups, such as groups of friends or teams, might often be in close proximity, which can be leveraged to locally deliver messages by applying edge caching or device-to-device (D2D) communication. In this work, a simulation study is conducted to investigate these potential traffic savings in the mobile network. It is based on a realistic communication model of the MMA WhatsApp and utilizes different models for human mobility. The user mobility and MMA communication are simulated for a single day in a small city to obtain the ratio of messages, which could be potentially transmitted locally when utilizing edge caching and D2D communication.

  @inproceedings{info3-inproceedings-2018-40, abstract = {Communication groups in mobile messaging applications (MMAs) multiply the data transmissions, because every message has to be delivered to all members of the communication group. Thereby, they put a high load on mobile networks. As the number of recipients is still comparably small, the dataintensive user-generated content cannot be handled efficiently in large content delivery networks. However, small communication groups, such as groups of friends or teams, might often be in close proximity, which can be leveraged to locally deliver messages by applying edge caching or device-to-device (D2D) communication. In this work, a simulation study is conducted to investigate these potential traffic savings in the mobile network. It is based on a realistic communication model of the MMA WhatsApp and utilizes different models for human mobility. The user mobility and MMA communication are simulated for a single day in a small city to obtain the ratio of messages, which could be potentially transmitted locally when utilizing edge caching and D2D communication.}, address = {Rome, Italy}, author = {Seufert, Michael and Schwind, Anika and Waigand, Marco and Hoßfeld, Tobias}, booktitle = {14th International Conference on Network and Service Management (CNSM)}, keywords = {can}, month = 11, title = {Potential Traffic Savings by Leveraging Proximity of Communication Groups in Mobile Messaging}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-40 %A Seufert, Michael %A Schwind, Anika %A Waigand, Marco %A Hoßfeld, Tobias %B 14th International Conference on Network and Service Management (CNSM) %C Rome, Italy %D 2018 %T Potential Traffic Savings by Leveraging Proximity of Communication Groups in Mobile Messaging %X Communication groups in mobile messaging applications (MMAs) multiply the data transmissions, because every message has to be delivered to all members of the communication group. Thereby, they put a high load on mobile networks. As the number of recipients is still comparably small, the dataintensive user-generated content cannot be handled efficiently in large content delivery networks. However, small communication groups, such as groups of friends or teams, might often be in close proximity, which can be leveraged to locally deliver messages by applying edge caching or device-to-device (D2D) communication. In this work, a simulation study is conducted to investigate these potential traffic savings in the mobile network. It is based on a realistic communication model of the MMA WhatsApp and utilizes different models for human mobility. The user mobility and MMA communication are simulated for a single day in a small city to obtain the ratio of messages, which could be potentially transmitted locally when utilizing edge caching and D2D communication.
• Machine Learning Models for YouTube QoE and User Engagement Prediction in Smartphones. Wassermann, Sarah; Wehner, Nikolas; Casas, Pedro. In WAIN - Workshop on AI in Networks and Distributed Systems. Toulouse, France, 2018.
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  Measuring and monitoring YouTube Quality of Experience is a challenging task, especially when dealing with cellular networks and smartphone users. Using a large-scale database of crowdsourced YouTube-QoE measurements in smartphones, we conceive multiple machine-learning models to infer different YouTube-QoE-relevant metrics and userbehavior- related metrics from network-level measurements, without requiring root access to the smartphone, video-player embedding, or any other reverse-engineering-like approaches. The dataset includes measurements from more than 360 users worldwide, spanning over the last five years. Our preliminary results suggest that QoE-based monitoring of YouTube mobile can be realized through machine learning models with high accuracy, relying only on network-related features and without accessing any higher-layer metric to perform the estimations.

  @inproceedings{info3-inproceedings-2018-54, abstract = {Measuring and monitoring YouTube Quality of Experience is a challenging task, especially when dealing with cellular networks and smartphone users. Using a large-scale database of crowdsourced YouTube-QoE measurements in smartphones, we conceive multiple machine-learning models to infer different YouTube-QoE-relevant metrics and userbehavior- related metrics from network-level measurements, without requiring root access to the smartphone, video-player embedding, or any other reverse-engineering-like approaches. The dataset includes measurements from more than 360 users worldwide, spanning over the last five years. Our preliminary results suggest that QoE-based monitoring of YouTube mobile can be realized through machine learning models with high accuracy, relying only on network-related features and without accessing any higher-layer metric to perform the estimations.}, address = {Toulouse, France}, author = {Wassermann, Sarah and Wehner, Nikolas and Casas, Pedro}, booktitle = {WAIN - Workshop on AI in Networks and Distributed Systems}, keywords = {old}, month = 11, title = {Machine Learning Models for YouTube QoE and User Engagement Prediction in Smartphones}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-54 %A Wassermann, Sarah %A Wehner, Nikolas %A Casas, Pedro %B WAIN - Workshop on AI in Networks and Distributed Systems %C Toulouse, France %D 2018 %T Machine Learning Models for YouTube QoE and User Engagement Prediction in Smartphones %X Measuring and monitoring YouTube Quality of Experience is a challenging task, especially when dealing with cellular networks and smartphone users. Using a large-scale database of crowdsourced YouTube-QoE measurements in smartphones, we conceive multiple machine-learning models to infer different YouTube-QoE-relevant metrics and userbehavior- related metrics from network-level measurements, without requiring root access to the smartphone, video-player embedding, or any other reverse-engineering-like approaches. The dataset includes measurements from more than 360 users worldwide, spanning over the last five years. Our preliminary results suggest that QoE-based monitoring of YouTube mobile can be realized through machine learning models with high accuracy, relying only on network-related features and without accessing any higher-layer metric to perform the estimations.
• Bridging the Gap Between Programming and Implementation of Networking Devices. Grigorjew, Alexej; Gray, Nicholas; Hoßfeld, Tobias; Shukla, Apoorv; Zinner, Thomas. In Student Workshop of the 14th International Conference on emerging Networking EXperiments and Technologies. 2018.
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  @inproceedings{info3-inproceedings-2018-49, author = {Grigorjew, Alexej and Gray, Nicholas and Hoßfeld, Tobias and Shukla, Apoorv and Zinner, Thomas}, booktitle = {Student Workshop of the 14th International Conference on emerging Networking EXperiments and Technologies}, keywords = {ngn}, month = 12, title = {Bridging the Gap Between Programming and Implementation of Networking Devices}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-49 %A Grigorjew, Alexej %A Gray, Nicholas %A Hoßfeld, Tobias %A Shukla, Apoorv %A Zinner, Thomas %B Student Workshop of the 14th International Conference on emerging Networking EXperiments and Technologies %D 2018 %T Bridging the Gap Between Programming and Implementation of Networking Devices
• Addressing Shortcomings of Existing DDoS Protection Software Using Software-Defined Networking. Iffländer, Lukas; Geissler, Stefan; Walter, Jürgen; Beierlieb, Lukas; Kounev, Samuel. In 9th Symposium on Software Performance 2018 (SSP’18). Hildesheim, Germany, 2018.
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  DDoS attacks are becoming increasingly frequent and violent. A typical type of attack is the TCP SYN flood, inhibiting a server from opening new TCP connections. Current countermeasures to this attack introduce inefficiencies by either reducing computing resources on the service host or creating new network bottlenecks. In this work, we present a novel approach to mitigate TCP SYN flood attacks using software-defined networking. We perform an initial evaluation of a proof-of-concept implementation that exhibits performance measures close to existing countermeasures while circumventing their inefficiencies.

  @inproceedings{info3-article-2018-7, abstract = {DDoS attacks are becoming increasingly frequent and violent. A typical type of attack is the TCP SYN flood, inhibiting a server from opening new TCP connections. Current countermeasures to this attack introduce inefficiencies by either reducing computing resources on the service host or creating new network bottlenecks. In this work, we present a novel approach to mitigate TCP SYN flood attacks using software-defined networking. We perform an initial evaluation of a proof-of-concept implementation that exhibits performance measures close to existing countermeasures while circumventing their inefficiencies.}, address = {Hildesheim, Germany}, author = {Iffländer, Lukas and Geissler, Stefan and Walter, Jürgen and Beierlieb, Lukas and Kounev, Samuel}, booktitle = {9th Symposium on Software Performance 2018 (SSP'18)}, keywords = {ngn}, month = 10, title = {Addressing Shortcomings of Existing DDoS Protection Software Using Software-Defined Networking}, year = 2018 }

  %0 Conference Paper %1 info3-article-2018-7 %A Iffländer, Lukas %A Geissler, Stefan %A Walter, Jürgen %A Beierlieb, Lukas %A Kounev, Samuel %B 9th Symposium on Software Performance 2018 (SSP'18) %C Hildesheim, Germany %D 2018 %T Addressing Shortcomings of Existing DDoS Protection Software Using Software-Defined Networking %X DDoS attacks are becoming increasingly frequent and violent. A typical type of attack is the TCP SYN flood, inhibiting a server from opening new TCP connections. Current countermeasures to this attack introduce inefficiencies by either reducing computing resources on the service host or creating new network bottlenecks. In this work, we present a novel approach to mitigate TCP SYN flood attacks using software-defined networking. We perform an initial evaluation of a proof-of-concept implementation that exhibits performance measures close to existing countermeasures while circumventing their inefficiencies.
• Performance Evaluation of Service Functions Chain Placement Algorithms in Edge Cloud. Dinh-Xuan, Lam; Seufert, Michael; Wamser, Florian; Vassilakis, Constantinos; Zafeiropoulos, Anastasios; Tran-Gia, Phuoc. In 30th International Teletraffic Congress (ITC30). Vienna, Austria, 2018.
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  The emergence of Network Function Virtualization (NFV) paradigm has become a potential solution dealing with the rapid growth of the global Internet traffic in the last decades. There, network appliances are transformed into Virtual Network Functions (VNF) running on a standard server. This promises to significantly reduce overall cost and energy consumption. Additionally, hardware-based network function chain is replaced by a chain of the VNFs, called Service Function Chain (SFC). The expected benefit of SFC is the reduction in the complexity when deploying heterogeneous network services. However, the considerable drawback of SFC is the distribution of the VNFs over different hosts. An inefficient placement of VNFs can induce a high latency within the chain and wasted server resources. In this work, we propose four placement algorithms that aim to efficiently place the SFC in servers with regard to minimizing service response time and resource utilization. Herein, heuristic approaches are evaluated against optimal solutions for the placement problems, which are formulated by using Integer Linear Programming. We evaluate and compare these placement strategies in a simulator. Our result shows that the optimized solutions produce lowest service response time and least server utilization in all types of simulated SFCs. On the other hand, the heuristic algorithms are also able to come close to the optimum by simple placing rules.

  @inproceedings{info3-inproceedings-2018-14, abstract = {The emergence of Network Function Virtualization (NFV) paradigm has become a potential solution dealing with the rapid growth of the global Internet traffic in the last decades. There, network appliances are transformed into Virtual Network Functions (VNF) running on a standard server. This promises to significantly reduce overall cost and energy consumption. Additionally, hardware-based network function chain is replaced by a chain of the VNFs, called Service Function Chain (SFC). The expected benefit of SFC is the reduction in the complexity when deploying heterogeneous network services. However, the considerable drawback of SFC is the distribution of the VNFs over different hosts. An inefficient placement of VNFs can induce a high latency within the chain and wasted server resources. In this work, we propose four placement algorithms that aim to efficiently place the SFC in servers with regard to minimizing service response time and resource utilization. Herein, heuristic approaches are evaluated against optimal solutions for the placement problems, which are formulated by using Integer Linear Programming. We evaluate and compare these placement strategies in a simulator. Our result shows that the optimized solutions produce lowest service response time and least server utilization in all types of simulated SFCs. On the other hand, the heuristic algorithms are also able to come close to the optimum by simple placing rules.}, address = {Vienna, Austria}, author = {Dinh-Xuan, Lam and Seufert, Michael and Wamser, Florian and Vassilakis, Constantinos and Zafeiropoulos, Anastasios and Tran-Gia, Phuoc}, booktitle = {30th International Teletraffic Congress (ITC30)}, keywords = {can}, month = {09}, title = {Performance Evaluation of Service Functions Chain Placement Algorithms in Edge Cloud}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-14 %A Dinh-Xuan, Lam %A Seufert, Michael %A Wamser, Florian %A Vassilakis, Constantinos %A Zafeiropoulos, Anastasios %A Tran-Gia, Phuoc %B 30th International Teletraffic Congress (ITC30) %C Vienna, Austria %D 2018 %T Performance Evaluation of Service Functions Chain Placement Algorithms in Edge Cloud %X The emergence of Network Function Virtualization (NFV) paradigm has become a potential solution dealing with the rapid growth of the global Internet traffic in the last decades. There, network appliances are transformed into Virtual Network Functions (VNF) running on a standard server. This promises to significantly reduce overall cost and energy consumption. Additionally, hardware-based network function chain is replaced by a chain of the VNFs, called Service Function Chain (SFC). The expected benefit of SFC is the reduction in the complexity when deploying heterogeneous network services. However, the considerable drawback of SFC is the distribution of the VNFs over different hosts. An inefficient placement of VNFs can induce a high latency within the chain and wasted server resources. In this work, we propose four placement algorithms that aim to efficiently place the SFC in servers with regard to minimizing service response time and resource utilization. Herein, heuristic approaches are evaluated against optimal solutions for the placement problems, which are formulated by using Integer Linear Programming. We evaluate and compare these placement strategies in a simulator. Our result shows that the optimized solutions produce lowest service response time and least server utilization in all types of simulated SFCs. On the other hand, the heuristic algorithms are also able to come close to the optimum by simple placing rules.
• Beauty is in the Eye of the Smartphone Holder - A Data Driven Analysis of YouTube Mobile QoE. Wehner, Nikolas; Wassermann, Sarah; Casas, Pedro; Seufert, Michael; Wamser, Florian. In 14th International Conference on Network and Service Management (CNSM). Rome, Italy, 2018.
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  Measuring the Quality of Experience (QoE) undergone by cellular network users has become paramount for cellular ISPs. Given its overwhelming dominance and ever-growing popularity, this paper focuses on the analysis of QoE for YouTube in mobile networks. Using a large-scale dataset of crowdsourced YouTube QoE measurements collected in smartphones with YoMoApp, we analyze the evolution of multiple relevant QoE-related metrics over time for YouTube mobile users. The dataset includes measurements from more than 360 users worldwide, spanning over the last five years. Our data-driven analysis shows a systematic performance and QoE improvement of YouTube in mobile devices over time, accompanied by an improvement of cellular network performance and by an optimization of the YouTube streaming behavior for smartphones.

  @inproceedings{info3-inproceedings-2018-39, abstract = {Measuring the Quality of Experience (QoE) undergone by cellular network users has become paramount for cellular ISPs. Given its overwhelming dominance and ever-growing popularity, this paper focuses on the analysis of QoE for YouTube in mobile networks. Using a large-scale dataset of crowdsourced YouTube QoE measurements collected in smartphones with YoMoApp, we analyze the evolution of multiple relevant QoE-related metrics over time for YouTube mobile users. The dataset includes measurements from more than 360 users worldwide, spanning over the last five years. Our data-driven analysis shows a systematic performance and QoE improvement of YouTube in mobile devices over time, accompanied by an improvement of cellular network performance and by an optimization of the YouTube streaming behavior for smartphones.}, address = {Rome, Italy}, author = {Wehner, Nikolas and Wassermann, Sarah and Casas, Pedro and Seufert, Michael and Wamser, Florian}, booktitle = {14th International Conference on Network and Service Management (CNSM)}, keywords = {can}, month = 11, title = {Beauty is in the Eye of the Smartphone Holder - A Data Driven Analysis of YouTube Mobile QoE}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-39 %A Wehner, Nikolas %A Wassermann, Sarah %A Casas, Pedro %A Seufert, Michael %A Wamser, Florian %B 14th International Conference on Network and Service Management (CNSM) %C Rome, Italy %D 2018 %T Beauty is in the Eye of the Smartphone Holder - A Data Driven Analysis of YouTube Mobile QoE %X Measuring the Quality of Experience (QoE) undergone by cellular network users has become paramount for cellular ISPs. Given its overwhelming dominance and ever-growing popularity, this paper focuses on the analysis of QoE for YouTube in mobile networks. Using a large-scale dataset of crowdsourced YouTube QoE measurements collected in smartphones with YoMoApp, we analyze the evolution of multiple relevant QoE-related metrics over time for YouTube mobile users. The dataset includes measurements from more than 360 users worldwide, spanning over the last five years. Our data-driven analysis shows a systematic performance and QoE improvement of YouTube in mobile devices over time, accompanied by an improvement of cellular network performance and by an optimization of the YouTube streaming behavior for smartphones.
• Exploring the Transmission Behaviour of Overwatch: The Source of Lag. Metzger, Florian; Heger, Roman. In 30th International Teletraffic Congress (ITC 30). 2018.
  • [ Abstract ]
  • [ BibTeX ]
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  This paper explores the full chain of lag contribution factors in a specific online multiplayer game, namely Overwatch: From creating input events over the network and back to displaying the results on the local screen. Together result in the dreaded end-to-end lag. which has a direct impact on the subjective quality one experiences when playing video games. In its investigation, this paper reveals surprising effects in the game's networking behavior that are omitted when colloquially talking about, e.g. a 60 Hz update rate, but must be considered nonetheless. These insights, gained from examining network traces of Overwatch matches that were played on a realistic, resource constrained PC, can then be used to refine end-to-end lag simulation models and reach a better understanding of all responsible components.

  @inproceedings{info3-inproceedings-2018-36, abstract = {This paper explores the full chain of lag contribution factors in a specific online multiplayer game, namely Overwatch: From creating input events over the network and back to displaying the results on the local screen. Together result in the dreaded end-to-end lag. which has a direct impact on the subjective quality one experiences when playing video games. In its investigation, this paper reveals surprising effects in the game's networking behavior that are omitted when colloquially talking about, e.g. a 60 Hz update rate, but must be considered nonetheless. These insights, gained from examining network traces of Overwatch matches that were played on a realistic, resource constrained PC, can then be used to refine end-to-end lag simulation models and reach a better understanding of all responsible components.}, author = {Metzger, Florian and Heger, Roman}, booktitle = {30th International Teletraffic Congress (ITC 30)}, keywords = {fullstack}, month = {09}, title = {Exploring the Transmission Behaviour of Overwatch: The Source of Lag}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-36 %A Metzger, Florian %A Heger, Roman %B 30th International Teletraffic Congress (ITC 30) %D 2018 %T Exploring the Transmission Behaviour of Overwatch: The Source of Lag %X This paper explores the full chain of lag contribution factors in a specific online multiplayer game, namely Overwatch: From creating input events over the network and back to displaying the results on the local screen. Together result in the dreaded end-to-end lag. which has a direct impact on the subjective quality one experiences when playing video games. In its investigation, this paper reveals surprising effects in the game's networking behavior that are omitted when colloquially talking about, e.g. a 60 Hz update rate, but must be considered nonetheless. These insights, gained from examining network traces of Overwatch matches that were played on a realistic, resource constrained PC, can then be used to refine end-to-end lag simulation models and reach a better understanding of all responsible components.
• Application of Visual Analysis to Detect and Analyze Patterns in VoIP Attack Traffic. Volodina, Ekaterina; Aziz, Adnan; Rathgeb, Erwin; Hoßfeld, Tobias. In 17th IEEE International Conference On Trust, Security And Privacy In Computing And Communications/12th IEEE International Conference On Big Data Science And Engineering (TrustCom/BigDataSE). 2018.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2018-35, author = {Volodina, Ekaterina and Aziz, Adnan and Rathgeb, Erwin and Hoßfeld, Tobias}, booktitle = {17th IEEE International Conference On Trust, Security And Privacy In Computing And Communications/12th IEEE International Conference On Big Data Science And Engineering (TrustCom/BigDataSE)}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Application of Visual Analysis to Detect and Analyze Patterns in VoIP Attack Traffic}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-35 %A Volodina, Ekaterina %A Aziz, Adnan %A Rathgeb, Erwin %A Hoßfeld, Tobias %B 17th IEEE International Conference On Trust, Security And Privacy In Computing And Communications/12th IEEE International Conference On Big Data Science And Engineering (TrustCom/BigDataSE) %D 2018 %T Application of Visual Analysis to Detect and Analyze Patterns in VoIP Attack Traffic
• Quality of Service Assessment of Live Video Streaming with a Remote-Controlled Drone. Loh, Frank; Wamser, Florian; Hoßfeld, Tobias; Tran-Gia, Phuoc. In IEEE Conference on Network Softwarization. Montreal, Canada, 2018.
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  Today's networks require a deep understanding of applications to optimize networks, efficiently design networks, and meet traffic demands, application heterogeneity, and application requirements. Current application areas include live video streaming and real-time applications, such as those that are named in 5G use cases with automation, disaster recovery, gaming, and Industry 4.0. In this work, we examine an application scenario with live video streaming and parallel real-time requirements in the uplink for disaster recovery. We study the quality of service (QoS) features of a remote-controlled drone. The drone is controlled via a tablet or smartphone while the video from the camera is transmitted from the drone to the user. There are high demands in both the uplink and downlink direction. The contribution of the work is the measurement of the QoS and application parameters for this scenario and the definition of influencing parameters for the application-layer.

  @inproceedings{info3-inproceedings-2018-31, abstract = {Today's networks require a deep understanding of applications to optimize networks, efficiently design networks, and meet traffic demands, application heterogeneity, and application requirements. Current application areas include live video streaming and real-time applications, such as those that are named in 5G use cases with automation, disaster recovery, gaming, and Industry 4.0. In this work, we examine an application scenario with live video streaming and parallel real-time requirements in the uplink for disaster recovery. We study the quality of service (QoS) features of a remote-controlled drone. The drone is controlled via a tablet or smartphone while the video from the camera is transmitted from the drone to the user. There are high demands in both the uplink and downlink direction. The contribution of the work is the measurement of the QoS and application parameters for this scenario and the definition of influencing parameters for the application-layer.}, address = {Montreal, Canada}, author = {Loh, Frank and Wamser, Florian and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {IEEE Conference on Network Softwarization}, keywords = {can}, month = {07}, title = {Quality of Service Assessment of Live Video Streaming with a Remote-Controlled Drone}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-31 %A Loh, Frank %A Wamser, Florian %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B IEEE Conference on Network Softwarization %C Montreal, Canada %D 2018 %T Quality of Service Assessment of Live Video Streaming with a Remote-Controlled Drone %X Today's networks require a deep understanding of applications to optimize networks, efficiently design networks, and meet traffic demands, application heterogeneity, and application requirements. Current application areas include live video streaming and real-time applications, such as those that are named in 5G use cases with automation, disaster recovery, gaming, and Industry 4.0. In this work, we examine an application scenario with live video streaming and parallel real-time requirements in the uplink for disaster recovery. We study the quality of service (QoS) features of a remote-controlled drone. The drone is controlled via a tablet or smartphone while the video from the camera is transmitted from the drone to the user. There are high demands in both the uplink and downlink direction. The contribution of the work is the measurement of the QoS and application parameters for this scenario and the definition of influencing parameters for the application-layer.
• Benchmarking the ONOS Controller with OFCProbe. Nguyen-Ngoc, Anh; Raffeck, Simon; Lange, Stanislav; Geissler, Stefan; Zinner, Thomas; Tran-Gia, Phuoc. In 7th International Conference on Communications and Electronics (ICCE). Hue, Vietnam, 2018.
  • [ Abstract ]
  • [ BibTeX ]
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  The increased popularity of Software Defined Networking (SDN) drives the development and research of all involved components. In particular, state-of-the-art SDN controllers are a central part of the resulting network architecture and have a large impact on the performance of the entire network. Hence, it is necessary to quantify various performance indicators of the SDN controller in order to assess its feasibility in the context of different network characteristics such as topology and network size w.r.t. the number of nodes and links. To this end, we extend the open-source controller benchmarking tool OFCProbe with several novel modules that are capable of recording relevant performance metrics and demonstrate their use in the context of benchmarking the ONOS controller. Furthermore, we investigate the impact of different types of topology characteristics on the performance of the controller. In this work, we focus on several performance indicators for SDN controllers. First, the time that the ONOS controller needs to discover the network topology and update its internal representation of the topology. Second, we investigate the duration of the installation of flow rules that are used for reactive path provisioning. Finally, we measure the response time of the controller when dealing with asynchronous messages.

  @inproceedings{info3-inproceedings-2018-15, abstract = {The increased popularity of Software Defined Networking (SDN) drives the development and research of all involved components. In particular, state-of-the-art SDN controllers are a central part of the resulting network architecture and have a large impact on the performance of the entire network. Hence, it is necessary to quantify various performance indicators of the SDN controller in order to assess its feasibility in the context of different network characteristics such as topology and network size w.r.t. the number of nodes and links. To this end, we extend the open-source controller benchmarking tool OFCProbe with several novel modules that are capable of recording relevant performance metrics and demonstrate their use in the context of benchmarking the ONOS controller. Furthermore, we investigate the impact of different types of topology characteristics on the performance of the controller. In this work, we focus on several performance indicators for SDN controllers. First, the time that the ONOS controller needs to discover the network topology and update its internal representation of the topology. Second, we investigate the duration of the installation of flow rules that are used for reactive path provisioning. Finally, we measure the response time of the controller when dealing with asynchronous messages.}, address = {Hue, Vietnam}, author = {Nguyen-Ngoc, Anh and Raffeck, Simon and Lange, Stanislav and Geissler, Stefan and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {7th International Conference on Communications and Electronics (ICCE)}, keywords = {ngn}, month = {07}, title = {Benchmarking the ONOS Controller with OFCProbe}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-15 %A Nguyen-Ngoc, Anh %A Raffeck, Simon %A Lange, Stanislav %A Geissler, Stefan %A Zinner, Thomas %A Tran-Gia, Phuoc %B 7th International Conference on Communications and Electronics (ICCE) %C Hue, Vietnam %D 2018 %T Benchmarking the ONOS Controller with OFCProbe %X The increased popularity of Software Defined Networking (SDN) drives the development and research of all involved components. In particular, state-of-the-art SDN controllers are a central part of the resulting network architecture and have a large impact on the performance of the entire network. Hence, it is necessary to quantify various performance indicators of the SDN controller in order to assess its feasibility in the context of different network characteristics such as topology and network size w.r.t. the number of nodes and links. To this end, we extend the open-source controller benchmarking tool OFCProbe with several novel modules that are capable of recording relevant performance metrics and demonstrate their use in the context of benchmarking the ONOS controller. Furthermore, we investigate the impact of different types of topology characteristics on the performance of the controller. In this work, we focus on several performance indicators for SDN controllers. First, the time that the ONOS controller needs to discover the network topology and update its internal representation of the topology. Second, we investigate the duration of the installation of flow rules that are used for reactive path provisioning. Finally, we measure the response time of the controller when dealing with asynchronous messages.
• Studying the Impact of HAS QoE Factors on the Standardized QoE Model P.1203. Seufert, Michael; Wehner, Nikolas; Casas, Pedro. In 3rd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE). Vienna, Austria, 2018.
  • [ Abstract ]
  • [ BibTeX ]
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  P.1203 is a recent standardized model for assessing the Quality of Experience (QoE) of HTTP Adaptive Video Streaming (HAS). However, its complex definition does not allow for a straightforward identification of the underlying assumptions. To overcome this issue, this work investigates the impact of the well-known QoE factors of HAS, namely, initial delay, stalling, and adaptation, on the output QoE score of the model. Therefore, parameter studies are conducted using a reference implementation of P.1203, and the model response to variations of the input QoE factors are compared to results of previous QoE studies in order to get a deeper understanding of the standardized model and its inherent weighting of the QoE factors of HAS.

  @inproceedings{info3-inproceedings-2018-44, abstract = {P.1203 is a recent standardized model for assessing the Quality of Experience (QoE) of HTTP Adaptive Video Streaming (HAS). However, its complex definition does not allow for a straightforward identification of the underlying assumptions. To overcome this issue, this work investigates the impact of the well-known QoE factors of HAS, namely, initial delay, stalling, and adaptation, on the output QoE score of the model. Therefore, parameter studies are conducted using a reference implementation of P.1203, and the model response to variations of the input QoE factors are compared to results of previous QoE studies in order to get a deeper understanding of the standardized model and its inherent weighting of the QoE factors of HAS.}, address = {Vienna, Austria}, author = {Seufert, Michael and Wehner, Nikolas and Casas, Pedro}, booktitle = {3rd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Studying the Impact of HAS QoE Factors on the Standardized QoE Model P.1203}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-44 %A Seufert, Michael %A Wehner, Nikolas %A Casas, Pedro %B 3rd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE) %C Vienna, Austria %D 2018 %T Studying the Impact of HAS QoE Factors on the Standardized QoE Model P.1203 %X P.1203 is a recent standardized model for assessing the Quality of Experience (QoE) of HTTP Adaptive Video Streaming (HAS). However, its complex definition does not allow for a straightforward identification of the underlying assumptions. To overcome this issue, this work investigates the impact of the well-known QoE factors of HAS, namely, initial delay, stalling, and adaptation, on the output QoE score of the model. Therefore, parameter studies are conducted using a reference implementation of P.1203, and the model response to variations of the input QoE factors are compared to results of previous QoE studies in order to get a deeper understanding of the standardized model and its inherent weighting of the QoE factors of HAS.
• Investigating the Impact of Advertisement Banners and Clips on Video QoE. Zach, Ondrej; Slanina, Martin; Seufert, Michael. In 3rd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE). Vienna, Austria, 2018.
  • [ Abstract ]
  • [ BibTeX ]
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  Although Quality of Experience (QoE) of Internet services can be affected by context influence factors, their actual impact is not widely investigated yet. In the context of online video services, web portals often display advertisement banners or clips to monetize their service. However, these advertisements can distract or annoy the users, which might degrade the QoE of the actual video service. In this work, two crowdsourcing studies were conducted to investigate the impact of advertisement banners and clips on video QoE. Therefore, both theoretical opinions on in-service advertisements and subjective quality ratings are evaluated. The findings confirm that advertisements are negatively perceived by users during service consumption, but a generally negative impact on video QoE cannot be supported, as the interplay of advertisement and the QoE of video services is rather complex.

  @inproceedings{info3-inproceedings-2018-43, abstract = {Although Quality of Experience (QoE) of Internet services can be affected by context influence factors, their actual impact is not widely investigated yet. In the context of online video services, web portals often display advertisement banners or clips to monetize their service. However, these advertisements can distract or annoy the users, which might degrade the QoE of the actual video service. In this work, two crowdsourcing studies were conducted to investigate the impact of advertisement banners and clips on video QoE. Therefore, both theoretical opinions on in-service advertisements and subjective quality ratings are evaluated. The findings confirm that advertisements are negatively perceived by users during service consumption, but a generally negative impact on video QoE cannot be supported, as the interplay of advertisement and the QoE of video services is rather complex.}, address = {Vienna, Austria}, author = {Zach, Ondrej and Slanina, Martin and Seufert, Michael}, booktitle = {3rd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Investigating the Impact of Advertisement Banners and Clips on Video QoE}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-43 %A Zach, Ondrej %A Slanina, Martin %A Seufert, Michael %B 3rd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE) %C Vienna, Austria %D 2018 %T Investigating the Impact of Advertisement Banners and Clips on Video QoE %X Although Quality of Experience (QoE) of Internet services can be affected by context influence factors, their actual impact is not widely investigated yet. In the context of online video services, web portals often display advertisement banners or clips to monetize their service. However, these advertisements can distract or annoy the users, which might degrade the QoE of the actual video service. In this work, two crowdsourcing studies were conducted to investigate the impact of advertisement banners and clips on video QoE. Therefore, both theoretical opinions on in-service advertisements and subjective quality ratings are evaluated. The findings confirm that advertisements are negatively perceived by users during service consumption, but a generally negative impact on video QoE cannot be supported, as the interplay of advertisement and the QoE of video services is rather complex.
• Evaluation of a Distributed Control Plane for Managing Heterogeneous SDN-enabled and Legacy Networks. Gray, Nicholas; Lange, Stanislav; Zinner, Thomas; Pfaff, Benedikt; Hock, David. In 7th International Conference on Communications and Electronics (ICCE). Hue, Vietnam, 2018.
  • [ Abstract ]
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  With the increasing number of devices, protocols and applications, today’s networks are becoming more and more complex. Hence, Software-defined Networking (SDN) tries to ad- dress this issue by separating the data from the control plane and by providing centralized interfaces for network configuration. As legacy devices cannot be replaced instantly due to high costs, both network segments have to be operated in coexistence with defined joints at their edges. To ensure a smooth operation, both controlling instances of these segments are required to exchange information. In this work, we design and implement a data model for storing the information needed to keep the controller and a Network Management System (NMS) synchronized, which are responsible for configuring the SDN-enabled network and the legacy devices respectively. For this, we implement and evaluate a total of three different synchronization strategies by the example of an SDN-based Bring Your Own Device (BYOD) use case. Index Terms—SDN, NMS, Management, Integration, Hetero- geneous Networks, Distributed Control Plane.

  @inproceedings{info3-inproceedings-2018-33, abstract = {With the increasing number of devices, protocols and applications, today’s networks are becoming more and more complex. Hence, Software-defined Networking (SDN) tries to ad- dress this issue by separating the data from the control plane and by providing centralized interfaces for network configuration. As legacy devices cannot be replaced instantly due to high costs, both network segments have to be operated in coexistence with defined joints at their edges. To ensure a smooth operation, both controlling instances of these segments are required to exchange information. In this work, we design and implement a data model for storing the information needed to keep the controller and a Network Management System (NMS) synchronized, which are responsible for configuring the SDN-enabled network and the legacy devices respectively. For this, we implement and evaluate a total of three different synchronization strategies by the example of an SDN-based Bring Your Own Device (BYOD) use case. Index Terms—SDN, NMS, Management, Integration, Hetero- geneous Networks, Distributed Control Plane.}, address = {Hue, Vietnam}, author = {Gray, Nicholas and Lange, Stanislav and Zinner, Thomas and Pfaff, Benedikt and Hock, David}, booktitle = {7th International Conference on Communications and Electronics (ICCE)}, keywords = {sardine}, month = {07}, title = {Evaluation of a Distributed Control Plane for Managing Heterogeneous SDN-enabled and Legacy Networks}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-33 %A Gray, Nicholas %A Lange, Stanislav %A Zinner, Thomas %A Pfaff, Benedikt %A Hock, David %B 7th International Conference on Communications and Electronics (ICCE) %C Hue, Vietnam %D 2018 %T Evaluation of a Distributed Control Plane for Managing Heterogeneous SDN-enabled and Legacy Networks %X With the increasing number of devices, protocols and applications, today’s networks are becoming more and more complex. Hence, Software-defined Networking (SDN) tries to ad- dress this issue by separating the data from the control plane and by providing centralized interfaces for network configuration. As legacy devices cannot be replaced instantly due to high costs, both network segments have to be operated in coexistence with defined joints at their edges. To ensure a smooth operation, both controlling instances of these segments are required to exchange information. In this work, we design and implement a data model for storing the information needed to keep the controller and a Network Management System (NMS) synchronized, which are responsible for configuring the SDN-enabled network and the legacy devices respectively. For this, we implement and evaluate a total of three different synchronization strategies by the example of an SDN-based Bring Your Own Device (BYOD) use case. Index Terms—SDN, NMS, Management, Integration, Hetero- geneous Networks, Distributed Control Plane.
• Enhancing Machine Learning based QoE Prediction by Ensemble Models. Casas, Pedro; Seufert, Michael; Wehner, Nikolas; Schwind, Anika; Wamser, Florian. In 3rd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE). Vienna, Austria, 2018.
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  The number of smartphones connected to wireless networks and the volume of wireless network traffic generated by such devices have dramatically increased in the last few years, making it more challenging to tackle wireless network monitoring applications. The high-dimensionality of network data provided by current smartphone devices opens the door to the massive application of machine learning approaches to improve different wireless networking applications. In this paper we study the specific problem of Quality of Experience (QoE) prediction for popular smartphone apps, using machine learning models and in-smartphone measurements. We evaluate and compare different models for the analysis of smartphone generated data, including single models as well as machine learning ensembles such as bagging, boosting and stacking. Results suggest that, while decision-tree based models are the most accurate single models to predict QoE, ensemble learning models, and in particular stacking ones, are capable to significantly increase accuracy prediction and overall classification performance.

  @inproceedings{info3-inproceedings-2018-29, abstract = {The number of smartphones connected to wireless networks and the volume of wireless network traffic generated by such devices have dramatically increased in the last few years, making it more challenging to tackle wireless network monitoring applications. The high-dimensionality of network data provided by current smartphone devices opens the door to the massive application of machine learning approaches to improve different wireless networking applications. In this paper we study the specific problem of Quality of Experience (QoE) prediction for popular smartphone apps, using machine learning models and in-smartphone measurements. We evaluate and compare different models for the analysis of smartphone generated data, including single models as well as machine learning ensembles such as bagging, boosting and stacking. Results suggest that, while decision-tree based models are the most accurate single models to predict QoE, ensemble learning models, and in particular stacking ones, are capable to significantly increase accuracy prediction and overall classification performance.}, address = {Vienna, Austria}, author = {Casas, Pedro and Seufert, Michael and Wehner, Nikolas and Schwind, Anika and Wamser, Florian}, booktitle = {3rd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE)}, keywords = {can}, month = {07}, title = {Enhancing Machine Learning based QoE Prediction by Ensemble Models}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-29 %A Casas, Pedro %A Seufert, Michael %A Wehner, Nikolas %A Schwind, Anika %A Wamser, Florian %B 3rd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE) %C Vienna, Austria %D 2018 %T Enhancing Machine Learning based QoE Prediction by Ensemble Models %X The number of smartphones connected to wireless networks and the volume of wireless network traffic generated by such devices have dramatically increased in the last few years, making it more challenging to tackle wireless network monitoring applications. The high-dimensionality of network data provided by current smartphone devices opens the door to the massive application of machine learning approaches to improve different wireless networking applications. In this paper we study the specific problem of Quality of Experience (QoE) prediction for popular smartphone apps, using machine learning models and in-smartphone measurements. We evaluate and compare different models for the analysis of smartphone generated data, including single models as well as machine learning ensembles such as bagging, boosting and stacking. Results suggest that, while decision-tree based models are the most accurate single models to predict QoE, ensemble learning models, and in particular stacking ones, are capable to significantly increase accuracy prediction and overall classification performance.
• Taming the complexity of artifact reproducibility. Flittner, Matthias; Bauer, Robert; Rizk, Amr; Geissler, Stefan; Zinner, Thomas; Zitterbart, Martina. In Proceedings of the Reproducibility Workshop. 2018.
  • [ Abstract ]
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  Reproducing research results, as it is required for peer review, can be a time-consuming and difficult task. In this work, we propose three approaches to improve the way of how research results can be substantiated and discuss their applicability. Our proposals are based on a brief study on evaluation methods (for SDN research) and insights from a comprehensive discussion on reproducibility.

  @inproceedings{info3-inproceedings-2018-45, abstract = {Reproducing research results, as it is required for peer review, can be a time-consuming and difficult task. In this work, we propose three approaches to improve the way of how research results can be substantiated and discuss their applicability. Our proposals are based on a brief study on evaluation methods (for SDN research) and insights from a comprehensive discussion on reproducibility.}, author = {Flittner, Matthias and Bauer, Robert and Rizk, Amr and Geissler, Stefan and Zinner, Thomas and Zitterbart, Martina}, booktitle = {Proceedings of the Reproducibility Workshop}, keywords = {ngn}, month = {08}, title = {Taming the complexity of artifact reproducibility}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-45 %A Flittner, Matthias %A Bauer, Robert %A Rizk, Amr %A Geissler, Stefan %A Zinner, Thomas %A Zitterbart, Martina %B Proceedings of the Reproducibility Workshop %D 2018 %T Taming the complexity of artifact reproducibility %X Reproducing research results, as it is required for peer review, can be a time-consuming and difficult task. In this work, we propose three approaches to improve the way of how research results can be substantiated and discuss their applicability. Our proposals are based on a brief study on evaluation methods (for SDN research) and insights from a comprehensive discussion on reproducibility.

• An AAL-Oriented Measurement-based Evaluation of Different HTTP-based Data Transport Protocols. Zinner, Thomas; Geissler, Stefan; Helmschrott, Fabian; Spinsante, Susanna; Braeken, An. In International Workshop on Protocols, Applications and Platforms for Enhanced Living Environments. 2017.
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  A key requirement for Active and Assisted Living (AAL) environments is the exchange of data between different communication endpoints to support wide range of services and applications. Used communication protocols need to support the bidirectional flow of information and have to be optimized with regard to security or latency constraints. To address these issues, RESTful approaches have recently gained much attention from the community. In this context, different application layer transport protocols can be used to realize the required data exchange. Besides HTTP/1.1, developed and standardized in the 1990s, new protocols like HTTP/2 and the QUIC transfer protocol my be suitable candidates. The impact of the different protocols on the overall performance for web and AAL services is still an open research question. This paper narrows this gap by conducting a measurement-based comparison of the three described protocols with regard to their performance in terms of web page loading times for Google web services.

  @inproceedings{info3-inproceedings-2017-5, abstract = {A key requirement for Active and Assisted Living (AAL) environments is the exchange of data between different communication endpoints to support wide range of services and applications. Used communication protocols need to support the bidirectional flow of information and have to be optimized with regard to security or latency constraints. To address these issues, RESTful approaches have recently gained much attention from the community. In this context, different application layer transport protocols can be used to realize the required data exchange. Besides HTTP/1.1, developed and standardized in the 1990s, new protocols like HTTP/2 and the QUIC transfer protocol my be suitable candidates. The impact of the different protocols on the overall performance for web and AAL services is still an open research question. This paper narrows this gap by conducting a measurement-based comparison of the three described protocols with regard to their performance in terms of web page loading times for Google web services.}, author = {Zinner, Thomas and Geissler, Stefan and Helmschrott, Fabian and Spinsante, Susanna and Braeken, An}, booktitle = {International Workshop on Protocols, Applications and Platforms for Enhanced Living Environments}, keywords = {ngn}, month = {02}, title = {An AAL-Oriented Measurement-based Evaluation of Different HTTP-based Data Transport Protocols}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-5 %A Zinner, Thomas %A Geissler, Stefan %A Helmschrott, Fabian %A Spinsante, Susanna %A Braeken, An %B International Workshop on Protocols, Applications and Platforms for Enhanced Living Environments %D 2017 %T An AAL-Oriented Measurement-based Evaluation of Different HTTP-based Data Transport Protocols %X A key requirement for Active and Assisted Living (AAL) environments is the exchange of data between different communication endpoints to support wide range of services and applications. Used communication protocols need to support the bidirectional flow of information and have to be optimized with regard to security or latency constraints. To address these issues, RESTful approaches have recently gained much attention from the community. In this context, different application layer transport protocols can be used to realize the required data exchange. Besides HTTP/1.1, developed and standardized in the 1990s, new protocols like HTTP/2 and the QUIC transfer protocol my be suitable candidates. The impact of the different protocols on the overall performance for web and AAL services is still an open research question. This paper narrows this gap by conducting a measurement-based comparison of the three described protocols with regard to their performance in terms of web page loading times for Google web services.
• An Approximation of the Backhaul Bandwidth Aggregation Potential Using a Partial Sharing Scheme. Burger, Valentin; Seufert, Michael; Zinner, Thomas; Tran-Gia, Phuoc. In 15th IFIP/IEEE International Symposium on Integrated Network Management (IM). Lisbon, Portugal, 2017.
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  To cope with the increasing demands of mobile devices and the limited capacity of cellular networks, mobile connections are offloaded to WiFi. The access capacity is further increased by aggregating backhaul bandwidth of WiFi access links. To analyze the performance of aggregated access links we develop a model for two and more cooperating systems sharing capacities using an offloading scheme. The state probabilities of the different cooperating systems in the analytic model are determined by a fixed point iterative procedure. By investigating an inner and outer composite system we are able to analyze the system in imbalanced load conditions where the system reaches its full potential utilizing spare bandwidth. To evaluate the robustness of the system against users that try to exploit the system, the bandwidth received by prioritized users is quantified.

  @inproceedings{info3-inproceedings-2017-1, abstract = {To cope with the increasing demands of mobile devices and the limited capacity of cellular networks, mobile connections are offloaded to WiFi. The access capacity is further increased by aggregating backhaul bandwidth of WiFi access links. To analyze the performance of aggregated access links we develop a model for two and more cooperating systems sharing capacities using an offloading scheme. The state probabilities of the different cooperating systems in the analytic model are determined by a fixed point iterative procedure. By investigating an inner and outer composite system we are able to analyze the system in imbalanced load conditions where the system reaches its full potential utilizing spare bandwidth. To evaluate the robustness of the system against users that try to exploit the system, the bandwidth received by prioritized users is quantified.}, address = {Lisbon, Portugal}, author = {Burger, Valentin and Seufert, Michael and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {15th IFIP/IEEE International Symposium on Integrated Network Management (IM)}, keywords = {can}, month = {05}, title = {An Approximation of the Backhaul Bandwidth Aggregation Potential Using a Partial Sharing Scheme}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-1 %A Burger, Valentin %A Seufert, Michael %A Zinner, Thomas %A Tran-Gia, Phuoc %B 15th IFIP/IEEE International Symposium on Integrated Network Management (IM) %C Lisbon, Portugal %D 2017 %T An Approximation of the Backhaul Bandwidth Aggregation Potential Using a Partial Sharing Scheme %X To cope with the increasing demands of mobile devices and the limited capacity of cellular networks, mobile connections are offloaded to WiFi. The access capacity is further increased by aggregating backhaul bandwidth of WiFi access links. To analyze the performance of aggregated access links we develop a model for two and more cooperating systems sharing capacities using an offloading scheme. The state probabilities of the different cooperating systems in the analytic model are determined by a fixed point iterative procedure. By investigating an inner and outer composite system we are able to analyze the system in imbalanced load conditions where the system reaches its full potential utilizing spare bandwidth. To evaluate the robustness of the system against users that try to exploit the system, the bandwidth received by prioritized users is quantified.
• Predicting QoE in Cellular Networks using Machine Learning and in-Smartphone Measurements. Casas, Pedro; D’Alconzo, Alessandro; Wamser, Florian; Seufert, Michael; Gardlo, Bruno; Schwind, Anika; Tran-Gia, Phuoc; Schatz, Raimund. In 9th International Conference on Quality of Multimedia Experience (QoMEX). Erfurt, Germany, 2017.
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  Monitoring the Quality of Experience (QoE) undergone by cellular network customers has become paramount for cellular ISPs, who need to ensure high quality levels to limit customer churn due to quality dissatisfaction. This paper tackles the problem of QoE monitoring, assessment and prediction in cellular networks, relying on end-user device (i.e., smartphone) QoS passive traffic measurements and QoE crowdsourced feedback. We conceive different QoE assessment models based on supervised machine learning techniques, which are capable to predict the QoE experienced by the end user of popular smartphone apps (e.g., YouTube and Facebook), using as input the passive in-device measurements. Using a rich QoE dataset derived from field trials in operational cellular networks, we benchmark the performance of multiple machine learning based predictors, and construct a decision-tree based model which is capable to predict the per-user overall experience and service acceptability with a success rate of 91% and 98% respectively. To the best of our knowledge, this is the first paper using end-user, in-device passive measurements and machine learning models to predict the QoE of smartphone users in operational cellular networks.

  @inproceedings{info3-inproceedings-2017-10, abstract = {Monitoring the Quality of Experience (QoE) undergone by cellular network customers has become paramount for cellular ISPs, who need to ensure high quality levels to limit customer churn due to quality dissatisfaction. This paper tackles the problem of QoE monitoring, assessment and prediction in cellular networks, relying on end-user device (i.e., smartphone) QoS passive traffic measurements and QoE crowdsourced feedback. We conceive different QoE assessment models based on supervised machine learning techniques, which are capable to predict the QoE experienced by the end user of popular smartphone apps (e.g., YouTube and Facebook), using as input the passive in-device measurements. Using a rich QoE dataset derived from field trials in operational cellular networks, we benchmark the performance of multiple machine learning based predictors, and construct a decision-tree based model which is capable to predict the per-user overall experience and service acceptability with a success rate of 91% and 98% respectively. To the best of our knowledge, this is the first paper using end-user, in-device passive measurements and machine learning models to predict the QoE of smartphone users in operational cellular networks.}, address = {Erfurt, Germany}, author = {Casas, Pedro and D'Alconzo, Alessandro and Wamser, Florian and Seufert, Michael and Gardlo, Bruno and Schwind, Anika and Tran-Gia, Phuoc and Schatz, Raimund}, booktitle = {9th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {can}, month = {05}, title = {Predicting QoE in Cellular Networks using Machine Learning and in-Smartphone Measurements}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-10 %A Casas, Pedro %A D'Alconzo, Alessandro %A Wamser, Florian %A Seufert, Michael %A Gardlo, Bruno %A Schwind, Anika %A Tran-Gia, Phuoc %A Schatz, Raimund %B 9th International Conference on Quality of Multimedia Experience (QoMEX) %C Erfurt, Germany %D 2017 %T Predicting QoE in Cellular Networks using Machine Learning and in-Smartphone Measurements %X Monitoring the Quality of Experience (QoE) undergone by cellular network customers has become paramount for cellular ISPs, who need to ensure high quality levels to limit customer churn due to quality dissatisfaction. This paper tackles the problem of QoE monitoring, assessment and prediction in cellular networks, relying on end-user device (i.e., smartphone) QoS passive traffic measurements and QoE crowdsourced feedback. We conceive different QoE assessment models based on supervised machine learning techniques, which are capable to predict the QoE experienced by the end user of popular smartphone apps (e.g., YouTube and Facebook), using as input the passive in-device measurements. Using a rich QoE dataset derived from field trials in operational cellular networks, we benchmark the performance of multiple machine learning based predictors, and construct a decision-tree based model which is capable to predict the per-user overall experience and service acceptability with a success rate of 91% and 98% respectively. To the best of our knowledge, this is the first paper using end-user, in-device passive measurements and machine learning models to predict the QoE of smartphone users in operational cellular networks.
• Viability of Wi-Fi Caches in an Era of HTTPS Prevalence. Moldovan, Christian; Burger, Valentin; Metzger, Florian; Surminski, Sebastian; Hoßfeld, Tobias. In 2017 IEEE International Conference on Communications Workshops (ICC Workshops). Paris, France, 2017.
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  Caches are often employed to better manage the ever-growing amount of global Internet traffic. Particularly, reverse proxies are often used to free up congested peering links and reduce inter-domain traffic. In addition, caches place content close to the edge, leading to lower latency which can be beneficial for many applications. In an effort to bring content even closer to end devices, home routers and public access points are now in the spotlight as a novel location for caches. Compared to CDNs, a Wi-Fi router only offers scarce storage and processing capabilities, putting an increased emphasis on resource management. In addition, a large share of traffic is transmitted through secured connections preventing the use of forward caches and other middle boxes. This paper strives to analyze how effective caching can be in public Wi-Fi routers. For this purpose, we conducted a field study with caches at public Wi-Fi hotspots in a field study. In addition, we present a queueing model for caches that we use to perform a mean-value analysis. We compare results from both methods in a performance analysis. Our results provide insights into difficulties of caching systems that are caused by an increase in the ratio of secured connections in the Internet.

  @inproceedings{info3-inproceedings-2017-8, abstract = {Caches are often employed to better manage the ever-growing amount of global Internet traffic. Particularly, reverse proxies are often used to free up congested peering links and reduce inter-domain traffic. In addition, caches place content close to the edge, leading to lower latency which can be beneficial for many applications. In an effort to bring content even closer to end devices, home routers and public access points are now in the spotlight as a novel location for caches. Compared to CDNs, a Wi-Fi router only offers scarce storage and processing capabilities, putting an increased emphasis on resource management. In addition, a large share of traffic is transmitted through secured connections preventing the use of forward caches and other middle boxes. This paper strives to analyze how effective caching can be in public Wi-Fi routers. For this purpose, we conducted a field study with caches at public Wi-Fi hotspots in a field study. In addition, we present a queueing model for caches that we use to perform a mean-value analysis. We compare results from both methods in a performance analysis. Our results provide insights into difficulties of caching systems that are caused by an increase in the ratio of secured connections in the Internet.}, address = {Paris, France}, author = {Moldovan, Christian and Burger, Valentin and Metzger, Florian and Surminski, Sebastian and Hoßfeld, Tobias}, booktitle = {2017 IEEE International Conference on Communications Workshops (ICC Workshops)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Viability of Wi-Fi Caches in an Era of HTTPS Prevalence}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-8 %A Moldovan, Christian %A Burger, Valentin %A Metzger, Florian %A Surminski, Sebastian %A Hoßfeld, Tobias %B 2017 IEEE International Conference on Communications Workshops (ICC Workshops) %C Paris, France %D 2017 %T Viability of Wi-Fi Caches in an Era of HTTPS Prevalence %X Caches are often employed to better manage the ever-growing amount of global Internet traffic. Particularly, reverse proxies are often used to free up congested peering links and reduce inter-domain traffic. In addition, caches place content close to the edge, leading to lower latency which can be beneficial for many applications. In an effort to bring content even closer to end devices, home routers and public access points are now in the spotlight as a novel location for caches. Compared to CDNs, a Wi-Fi router only offers scarce storage and processing capabilities, putting an increased emphasis on resource management. In addition, a large share of traffic is transmitted through secured connections preventing the use of forward caches and other middle boxes. This paper strives to analyze how effective caching can be in public Wi-Fi routers. For this purpose, we conducted a field study with caches at public Wi-Fi hotspots in a field study. In addition, we present a queueing model for caches that we use to perform a mean-value analysis. We compare results from both methods in a performance analysis. Our results provide insights into difficulties of caching systems that are caused by an increase in the ratio of secured connections in the Internet.
• On Use of Crowdsourcing for H.264/AVC and H.265/HEVC Video Quality Evaluation. Zach, Ondrej; Seufert, Michael; Hirth, Matthias; Slanina, Martin; Tran-Gia, Phuoc. In Radioelektronika. Brno, Czech Republic, 2017.
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  Crowdsourcing has become a popular method in the field of video quality evaluation. Gathering the opinion of the users using crowdsourcing is quick and relatively cheap but such a study has to be designed very carefully in order to give relevant results. So far, the majority of the QoE studies using crowdsourcing has been focusing on the performance of H.264/AVC algorithm in different situations (such as encoder settings, stalling effects, etc). Modern video coding methods, however, are only rarely tested using the crowdsourcing approach. We designed a study comparing the performance of both H.264/AVC and H.265/HEVC standards in the crowdsourcing environment. We deal with the possibilities of delivering and presenting the HEVC encoded content to the participants of the crowdsourcing study and potential challenges. Finally, the study was performed using Microworkers platform and gathered results are then compared with three different objective video quality metrics.

  @inproceedings{info3-inproceedings-2017-7, abstract = {Crowdsourcing has become a popular method in the field of video quality evaluation. Gathering the opinion of the users using crowdsourcing is quick and relatively cheap but such a study has to be designed very carefully in order to give relevant results. So far, the majority of the QoE studies using crowdsourcing has been focusing on the performance of H.264/AVC algorithm in different situations (such as encoder settings, stalling effects, etc). Modern video coding methods, however, are only rarely tested using the crowdsourcing approach. We designed a study comparing the performance of both H.264/AVC and H.265/HEVC standards in the crowdsourcing environment. We deal with the possibilities of delivering and presenting the HEVC encoded content to the participants of the crowdsourcing study and potential challenges. Finally, the study was performed using Microworkers platform and gathered results are then compared with three different objective video quality metrics.}, address = {Brno, Czech Republic}, author = {Zach, Ondrej and Seufert, Michael and Hirth, Matthias and Slanina, Martin and Tran-Gia, Phuoc}, booktitle = {Radioelektronika}, keywords = {can}, month = {04}, title = {On Use of Crowdsourcing for H.264/AVC and H.265/HEVC Video Quality Evaluation}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-7 %A Zach, Ondrej %A Seufert, Michael %A Hirth, Matthias %A Slanina, Martin %A Tran-Gia, Phuoc %B Radioelektronika %C Brno, Czech Republic %D 2017 %T On Use of Crowdsourcing for H.264/AVC and H.265/HEVC Video Quality Evaluation %X Crowdsourcing has become a popular method in the field of video quality evaluation. Gathering the opinion of the users using crowdsourcing is quick and relatively cheap but such a study has to be designed very carefully in order to give relevant results. So far, the majority of the QoE studies using crowdsourcing has been focusing on the performance of H.264/AVC algorithm in different situations (such as encoder settings, stalling effects, etc). Modern video coding methods, however, are only rarely tested using the crowdsourcing approach. We designed a study comparing the performance of both H.264/AVC and H.265/HEVC standards in the crowdsourcing environment. We deal with the possibilities of delivering and presenting the HEVC encoded content to the participants of the crowdsourcing study and potential challenges. Finally, the study was performed using Microworkers platform and gathered results are then compared with three different objective video quality metrics.
• Betas: Deriving Quantiles from MOS-QoS Relations of IQX Models for QoE Management. Hoßfeld, Tobias; Fiedler, Markus; Gustafsson, Jörgen. In IFIP/IEEE International Workshop on Quality of Experience Management (QoE-Management). Lisbon, Portugal, 2017.
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  @inproceedings{info3-inproceedings-2017-25, address = {Lisbon, Portugal}, author = {Hoßfeld, Tobias and Fiedler, Markus and Gustafsson, Jörgen}, booktitle = {IFIP/IEEE International Workshop on Quality of Experience Management (QoE-Management)}, keywords = {sys:hidden:inproceedings}, title = {Betas: Deriving Quantiles from MOS-QoS Relations of IQX Models for QoE Management}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-25 %A Hoßfeld, Tobias %A Fiedler, Markus %A Gustafsson, Jörgen %B IFIP/IEEE International Workshop on Quality of Experience Management (QoE-Management) %C Lisbon, Portugal %D 2017 %T Betas: Deriving Quantiles from MOS-QoS Relations of IQX Models for QoE Management
• Comparison of the Initial Delay for Video Playout Start for Different HTTP-based Transport Protocols. Zinner, Thomas; Geissler, Stefan; Helmschrott, Fabian; Burger, Valentin. In Workshop on Quality of Experience Management. 2017.
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  This paper details a measurement study on the impact of different HTTP-based application layer protocols, namely HTTP/1, HTTP/2 and QUIC, on video streaming performance. In this context we evaluate the influence on the initial delay until video playout is started using the live version of the YouTube platform. Furthermore, we evaluate how different network parameters, i.e. bandwidth, RTTs and packet loss influence the different protocols. This work presents an verview over the characteristics of the compared protocols and presents a detailed measurement methodology on how the data has been obtained. Finally, the observed data is evaluated in the context of YouTube video streaming.

  @inproceedings{info3-inproceedings-2017-6, abstract = {This paper details a measurement study on the impact of different HTTP-based application layer protocols, namely HTTP/1, HTTP/2 and QUIC, on video streaming performance. In this context we evaluate the influence on the initial delay until video playout is started using the live version of the YouTube platform. Furthermore, we evaluate how different network parameters, i.e. bandwidth, RTTs and packet loss influence the different protocols. This work presents an verview over the characteristics of the compared protocols and presents a detailed measurement methodology on how the data has been obtained. Finally, the observed data is evaluated in the context of YouTube video streaming.}, author = {Zinner, Thomas and Geissler, Stefan and Helmschrott, Fabian and Burger, Valentin}, booktitle = {Workshop on Quality of Experience Management}, keywords = {ngn}, month = {02}, title = {Comparison of the Initial Delay for Video Playout Start for Different HTTP-based Transport Protocols}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-6 %A Zinner, Thomas %A Geissler, Stefan %A Helmschrott, Fabian %A Burger, Valentin %B Workshop on Quality of Experience Management %D 2017 %T Comparison of the Initial Delay for Video Playout Start for Different HTTP-based Transport Protocols %X This paper details a measurement study on the impact of different HTTP-based application layer protocols, namely HTTP/1, HTTP/2 and QUIC, on video streaming performance. In this context we evaluate the influence on the initial delay until video playout is started using the live version of the YouTube platform. Furthermore, we evaluate how different network parameters, i.e. bandwidth, RTTs and packet loss influence the different protocols. This work presents an verview over the characteristics of the compared protocols and presents a detailed measurement methodology on how the data has been obtained. Finally, the observed data is evaluated in the context of YouTube video streaming.
• TableVisor 2.0: Towards Full-Featured, Scalable and Hardware-Independent Multi Table Processing. Geissler, Stefan; Gebert, Steffen; Herrnleben, Stefan; Zinner, Thomas; Bauer, Robert; Jarschel, Michael. In NetSoft 2017, Best Student Paper Award. 2017.
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  Modern Software Defined Networking (SDN) appli- cations rely on sophisticated packet processing. However, there is a mismatch between control plane requirements and data plane capabilities caused by increasing hardware heterogeneity. To overcome this challenge, we propose TableVisor, a proxy-layer for the OpenFlow control channel that enables the flexible and scalable abstraction of multiple physical devices into one emu- lated data plane switch that meets the requirements of the control plane application. TableVisor registers with the SDN controller as a single switch with use-case specific capabilities. It translates the instructions and rules from the control application towards the appropriate physical device where they are executed. In this paper, we present the updated architecture and functionality of TableVisor as well as first evaluation results based on testbed experiments.

  @inproceedings{info3-inproceedings-2017-4, abstract = {Modern Software Defined Networking (SDN) appli- cations rely on sophisticated packet processing. However, there is a mismatch between control plane requirements and data plane capabilities caused by increasing hardware heterogeneity. To overcome this challenge, we propose TableVisor, a proxy-layer for the OpenFlow control channel that enables the flexible and scalable abstraction of multiple physical devices into one emu- lated data plane switch that meets the requirements of the control plane application. TableVisor registers with the SDN controller as a single switch with use-case specific capabilities. It translates the instructions and rules from the control application towards the appropriate physical device where they are executed. In this paper, we present the updated architecture and functionality of TableVisor as well as first evaluation results based on testbed experiments.}, author = {Geissler, Stefan and Gebert, Steffen and Herrnleben, Stefan and Zinner, Thomas and Bauer, Robert and Jarschel, Michael}, booktitle = {NetSoft 2017, Best Student Paper Award}, keywords = {sendate}, month = {02}, title = {TableVisor 2.0: Towards Full-Featured, Scalable and Hardware-Independent Multi Table Processing}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-4 %A Geissler, Stefan %A Gebert, Steffen %A Herrnleben, Stefan %A Zinner, Thomas %A Bauer, Robert %A Jarschel, Michael %B NetSoft 2017, Best Student Paper Award %D 2017 %T TableVisor 2.0: Towards Full-Featured, Scalable and Hardware-Independent Multi Table Processing %X Modern Software Defined Networking (SDN) appli- cations rely on sophisticated packet processing. However, there is a mismatch between control plane requirements and data plane capabilities caused by increasing hardware heterogeneity. To overcome this challenge, we propose TableVisor, a proxy-layer for the OpenFlow control channel that enables the flexible and scalable abstraction of multiple physical devices into one emu- lated data plane switch that meets the requirements of the control plane application. TableVisor registers with the SDN controller as a single switch with use-case specific capabilities. It translates the instructions and rules from the control application towards the appropriate physical device where they are executed. In this paper, we present the updated architecture and functionality of TableVisor as well as first evaluation results based on testbed experiments.
• No Silver Bullet: QoE Metrics, QoE Fairness, and User Diversity in the Context of QoE Management. Hoßfeld, Tobias; Heegaard, Poul E.; Skorin-Kapov, Lea; Varela, Martin. In 9th International Conference on Quality of Multimedia Experience (QoMEX 2017). Erfurt, Germany, 2017.
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  @inproceedings{info3-inproceedings-2017-23, address = {Erfurt, Germany}, author = {Hoßfeld, Tobias and Heegaard, Poul E. and Skorin-Kapov, Lea and Varela, Martin}, booktitle = {9th International Conference on Quality of Multimedia Experience (QoMEX 2017)}, keywords = {sys:hidden:inproceedings}, title = {No Silver Bullet: QoE Metrics, QoE Fairness, and User Diversity in the Context of QoE Management}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-23 %A Hoßfeld, Tobias %A Heegaard, Poul E. %A Skorin-Kapov, Lea %A Varela, Martin %B 9th International Conference on Quality of Multimedia Experience (QoMEX 2017) %C Erfurt, Germany %D 2017 %T No Silver Bullet: QoE Metrics, QoE Fairness, and User Diversity in the Context of QoE Management
• The BitTorrent Peer Collector Problem. Lareida, Andri; Hoßfeld, Tobias; Stiller, Burkhard. In IFIP/IEEE International Symposium on Integrated Network Management. Lisbon, Portugal, 2017.
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  @inproceedings{info3-inproceedings-2017-24, address = {Lisbon, Portugal}, author = {Lareida, Andri and Hoßfeld, Tobias and Stiller, Burkhard}, booktitle = {IFIP/IEEE International Symposium on Integrated Network Management}, keywords = {sys:hidden:inproceedings}, title = {The BitTorrent Peer Collector Problem}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-24 %A Lareida, Andri %A Hoßfeld, Tobias %A Stiller, Burkhard %B IFIP/IEEE International Symposium on Integrated Network Management %C Lisbon, Portugal %D 2017 %T The BitTorrent Peer Collector Problem
• A Priori State Synchronization for Fast Failover of Stateful Firewall VNFs. Gray, Nicholas; Lorenz, Class; Müssig, Alexander; Gebert, Steffen; Zinner, Thomas; Tran-Gia, Phuoc. In Workshop on Software-Defined Networking and Network Function Virtualization for Flexible Network Management (SDNFlex 2017). Göttingen, Germany, 2017.
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  Network Functions Virtualization (NFV) replaces physical middleboxes with software instances running network functions in cloud environments. To support this new paradigm, it is necessary to port the code basis from highly specialized hardware devices to virtual machines running on COTS hard- ware. In order to fully exploit the inherent capabilities of cloud environments it is further necessary to redesign the software to support a large amount of distributed, cooperating function instances instead of single, isolated and monolithic instances. This development can be observed for network functions like stateful firewalling. Until now, available software firewalls lack support for active/active operation in clustered environments, which hinders horizontal scalability. This is due to the fact that the required synchronization of connection states among the cluster’s instances is an impediment that still has to be resolved. Therefore, this work investigates different synchronization strategies and mechanisms, which allow to share connection states among the cluster to maintain scalability and high-availability

  @inproceedings{info3-inproceedings-2017-2, abstract = {Network Functions Virtualization (NFV) replaces physical middleboxes with software instances running network functions in cloud environments. To support this new paradigm, it is necessary to port the code basis from highly specialized hardware devices to virtual machines running on COTS hard- ware. In order to fully exploit the inherent capabilities of cloud environments it is further necessary to redesign the software to support a large amount of distributed, cooperating function instances instead of single, isolated and monolithic instances. This development can be observed for network functions like stateful firewalling. Until now, available software firewalls lack support for active/active operation in clustered environments, which hinders horizontal scalability. This is due to the fact that the required synchronization of connection states among the cluster’s instances is an impediment that still has to be resolved. Therefore, this work investigates different synchronization strategies and mechanisms, which allow to share connection states among the cluster to maintain scalability and high-availability}, address = {Göttingen, Germany}, author = {Gray, Nicholas and Lorenz, Class and Müssig, Alexander and Gebert, Steffen and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {Workshop on Software-Defined Networking and Network Function Virtualization for Flexible Network Management (SDNFlex 2017)}, keywords = {sardine}, title = {A Priori State Synchronization for Fast Failover of Stateful Firewall VNFs}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-2 %A Gray, Nicholas %A Lorenz, Class %A Müssig, Alexander %A Gebert, Steffen %A Zinner, Thomas %A Tran-Gia, Phuoc %B Workshop on Software-Defined Networking and Network Function Virtualization for Flexible Network Management (SDNFlex 2017) %C Göttingen, Germany %D 2017 %T A Priori State Synchronization for Fast Failover of Stateful Firewall VNFs %X Network Functions Virtualization (NFV) replaces physical middleboxes with software instances running network functions in cloud environments. To support this new paradigm, it is necessary to port the code basis from highly specialized hardware devices to virtual machines running on COTS hard- ware. In order to fully exploit the inherent capabilities of cloud environments it is further necessary to redesign the software to support a large amount of distributed, cooperating function instances instead of single, isolated and monolithic instances. This development can be observed for network functions like stateful firewalling. Until now, available software firewalls lack support for active/active operation in clustered environments, which hinders horizontal scalability. This is due to the fact that the required synchronization of connection states among the cluster’s instances is an impediment that still has to be resolved. Therefore, this work investigates different synchronization strategies and mechanisms, which allow to share connection states among the cluster to maintain scalability and high-availability
• Unsupervised QoE Field Study for Mobile YouTube Video Streaming with YoMoApp. Seufert, Michael; Wehner, Nikolas; Wamser, Florian; Casas, Pedro; D’Alconzo, Alessandro; Tran-Gia, Phuoc. In 9th International Conference on Quality of Multimedia Experience (QoMEX). Erfurt, Germany, 2017.
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  YoMoApp (YouTube Monitoring App) is an Android app to monitor mobile YouTube video streaming on both application- and network-layer. Additionally, it allows to collect subjective Quality of Experience (QoE) feedback of end users. During the development of the app, the stable versions of YoMoApp were already available in the Google Play Store, and the app was downloaded, installed, and used on many devices to monitor streaming sessions. As the app was not advertised in special campaigns or used for dedicated QoE studies, the monitored streaming sessions of this period compose the data set of a large unsupervised field study. The collected data set is evaluated to characterize current mobile YouTube streaming on both application and network layers. Furthermore, the problems and methodology to obtain QoE results from such unsupervised field study are discussed together with the actual QoE results. Correlations between QoE factors are investigated, and the QoE of clusters of similar streaming sessions is analyzed.

  @inproceedings{info3-inproceedings-2017-9, abstract = {YoMoApp (YouTube Monitoring App) is an Android app to monitor mobile YouTube video streaming on both application- and network-layer. Additionally, it allows to collect subjective Quality of Experience (QoE) feedback of end users. During the development of the app, the stable versions of YoMoApp were already available in the Google Play Store, and the app was downloaded, installed, and used on many devices to monitor streaming sessions. As the app was not advertised in special campaigns or used for dedicated QoE studies, the monitored streaming sessions of this period compose the data set of a large unsupervised field study. The collected data set is evaluated to characterize current mobile YouTube streaming on both application and network layers. Furthermore, the problems and methodology to obtain QoE results from such unsupervised field study are discussed together with the actual QoE results. Correlations between QoE factors are investigated, and the QoE of clusters of similar streaming sessions is analyzed.}, address = {Erfurt, Germany}, author = {Seufert, Michael and Wehner, Nikolas and Wamser, Florian and Casas, Pedro and D'Alconzo, Alessandro and Tran-Gia, Phuoc}, booktitle = {9th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {can}, month = {05}, title = {Unsupervised QoE Field Study for Mobile YouTube Video Streaming with YoMoApp}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-9 %A Seufert, Michael %A Wehner, Nikolas %A Wamser, Florian %A Casas, Pedro %A D'Alconzo, Alessandro %A Tran-Gia, Phuoc %B 9th International Conference on Quality of Multimedia Experience (QoMEX) %C Erfurt, Germany %D 2017 %T Unsupervised QoE Field Study for Mobile YouTube Video Streaming with YoMoApp %X YoMoApp (YouTube Monitoring App) is an Android app to monitor mobile YouTube video streaming on both application- and network-layer. Additionally, it allows to collect subjective Quality of Experience (QoE) feedback of end users. During the development of the app, the stable versions of YoMoApp were already available in the Google Play Store, and the app was downloaded, installed, and used on many devices to monitor streaming sessions. As the app was not advertised in special campaigns or used for dedicated QoE studies, the monitored streaming sessions of this period compose the data set of a large unsupervised field study. The collected data set is evaluated to characterize current mobile YouTube streaming on both application and network layers. Furthermore, the problems and methodology to obtain QoE results from such unsupervised field study are discussed together with the actual QoE results. Correlations between QoE factors are investigated, and the QoE of clusters of similar streaming sessions is analyzed.
• Unperturbed Video Streaming QoE Under Web Page Related Context Factors. Seufert, Michael; Zach, Ondrej; Slanina, Martin; Tran-Gia, Phuoc. In 9th International Conference on Quality of Multimedia Experience (QoMEX). Erfurt, Germany, 2017.
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  Quality of Experience (QoE) of Internet services is affected by human, system, and context influence factors. While most QoE studies so far are focused on system factors only, this work will assess the impact of context factors of video streaming on QoE. As video streaming is mostly consumed from web pages, such as video portals, the investigated test conditions are applied to the web page, which embeds the video player. Therefore, the study of context factors is implicitly conducted within a crowdsourced QoE study. The test conditions considered different page load times, poster image qualities, and displayed advertisements on the web page, which are typical context factors when consuming a video streaming service. The results of the study show that the modification of the context factors on the streaming web page leaves the users' QoE rating unperturbed, which suggests that the investigated context factors have a negligible impact on video streaming QoE, or that the rating task of the subjective QoE study superimposed the context factors.

  @inproceedings{info3-inproceedings-2017-11, abstract = {Quality of Experience (QoE) of Internet services is affected by human, system, and context influence factors. While most QoE studies so far are focused on system factors only, this work will assess the impact of context factors of video streaming on QoE. As video streaming is mostly consumed from web pages, such as video portals, the investigated test conditions are applied to the web page, which embeds the video player. Therefore, the study of context factors is implicitly conducted within a crowdsourced QoE study. The test conditions considered different page load times, poster image qualities, and displayed advertisements on the web page, which are typical context factors when consuming a video streaming service. The results of the study show that the modification of the context factors on the streaming web page leaves the users' QoE rating unperturbed, which suggests that the investigated context factors have a negligible impact on video streaming QoE, or that the rating task of the subjective QoE study superimposed the context factors.}, address = {Erfurt, Germany}, author = {Seufert, Michael and Zach, Ondrej and Slanina, Martin and Tran-Gia, Phuoc}, booktitle = {9th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {can}, month = {05}, title = {Unperturbed Video Streaming QoE Under Web Page Related Context Factors}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-11 %A Seufert, Michael %A Zach, Ondrej %A Slanina, Martin %A Tran-Gia, Phuoc %B 9th International Conference on Quality of Multimedia Experience (QoMEX) %C Erfurt, Germany %D 2017 %T Unperturbed Video Streaming QoE Under Web Page Related Context Factors %X Quality of Experience (QoE) of Internet services is affected by human, system, and context influence factors. While most QoE studies so far are focused on system factors only, this work will assess the impact of context factors of video streaming on QoE. As video streaming is mostly consumed from web pages, such as video portals, the investigated test conditions are applied to the web page, which embeds the video player. Therefore, the study of context factors is implicitly conducted within a crowdsourced QoE study. The test conditions considered different page load times, poster image qualities, and displayed advertisements on the web page, which are typical context factors when consuming a video streaming service. The results of the study show that the modification of the context factors on the streaming web page leaves the users' QoE rating unperturbed, which suggests that the investigated context factors have a negligible impact on video streaming QoE, or that the rating task of the subjective QoE study superimposed the context factors.
• EdgeNetworkCloudSim: Placement of Service Chains in Edge Clouds Using NetworkCloudSim. Seufert, Michael; Kamneng Kwam, Brice; Wamser, Florian; Tran-Gia, Phuoc. In 1st IEEE International Workshop on Network Programmability - From the Data Center to the Ground (NetFoG). Bologna, Italy, 2017.
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  Edge cloud computing is a trending paradigm, which extends cloud computing by additionally utilizing computing resources at the network edge, e.g., at mobile base stations. Especially personalized services can be instantiated or migrated close to end users, which improves the latency and supports user mobility. However, the placement of the service chains is crucial for the performance of the services and the energy consumption of the edge cloud platform, and appropriate algorithms have to be designed. To support the simulative performance evaluation of such algorithms, EdgeNetworkCloudSim was developed. It is an extension of NetworkCloudSim, and allows to simulate and evaluate the orchestration and consolidation of service chains in an edge network cloud.

  @inproceedings{info3-inproceedings-2017-12, abstract = {Edge cloud computing is a trending paradigm, which extends cloud computing by additionally utilizing computing resources at the network edge, e.g., at mobile base stations. Especially personalized services can be instantiated or migrated close to end users, which improves the latency and supports user mobility. However, the placement of the service chains is crucial for the performance of the services and the energy consumption of the edge cloud platform, and appropriate algorithms have to be designed. To support the simulative performance evaluation of such algorithms, EdgeNetworkCloudSim was developed. It is an extension of NetworkCloudSim, and allows to simulate and evaluate the orchestration and consolidation of service chains in an edge network cloud.}, address = {Bologna, Italy}, author = {Seufert, Michael and Kamneng Kwam, Brice and Wamser, Florian and Tran-Gia, Phuoc}, booktitle = {1st IEEE International Workshop on Network Programmability - From the Data Center to the Ground (NetFoG)}, keywords = {can}, month = {07}, title = {EdgeNetworkCloudSim: Placement of Service Chains in Edge Clouds Using NetworkCloudSim}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-12 %A Seufert, Michael %A Kamneng Kwam, Brice %A Wamser, Florian %A Tran-Gia, Phuoc %B 1st IEEE International Workshop on Network Programmability - From the Data Center to the Ground (NetFoG) %C Bologna, Italy %D 2017 %T EdgeNetworkCloudSim: Placement of Service Chains in Edge Clouds Using NetworkCloudSim %X Edge cloud computing is a trending paradigm, which extends cloud computing by additionally utilizing computing resources at the network edge, e.g., at mobile base stations. Especially personalized services can be instantiated or migrated close to end users, which improves the latency and supports user mobility. However, the placement of the service chains is crucial for the performance of the services and the energy consumption of the edge cloud platform, and appropriate algorithms have to be designed. To support the simulative performance evaluation of such algorithms, EdgeNetworkCloudSim was developed. It is an extension of NetworkCloudSim, and allows to simulate and evaluate the orchestration and consolidation of service chains in an edge network cloud.
• Study on the Accuracy of QoE Monitoring for HTTP Adaptive Video Streaming Using VNF. Dinh-Xuan, Lam; Seufert, Michael; Wamser, Florian; Tran-Gia, Phuoc. In 1st IFIP/IEEE International Workshop on Quality of Experience Management (QoE-Management). Lisbon, Portugal, 2017.
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  The fast growth of HTTP video streaming is responsible for a huge amount of traffic over the past few years. Due to the variety and popularity of video content, more and more people are watching videos on the smart TV or on mobile devices. As a result, a potential market is emerging for video providers, which can significantly increase their revenues. In order to offer users a good experience, adaptive video streaming has been introduced to adapt the video quality to the network conditions. Nevertheless, it is still difficult for the network operators to assess the actual video quality on the device of the users and therefore they can not react to improve the service on the network. In this work, we propose a Virtual Network Function (VNF) to monitor the Quality of Experience (QoE) for online video service in the network. To conduct the study, on the one hand, we design a VNF monitoring to measure the video quality and estimate the QoE at the client machine. Our function is placed in two locations nearby and far away from the user to analyze the impact of geographical placement of the VNF on its performance. On the other hand, we set up a local testbed to examine the functional operation and measure the actual video buffer from a client web browser directly to validate the accuracy of the function. Our findings show that with respect to function placement, the VNF has high accuracy in estimating the QoE if it is deployed at the edge network close to the user. However, the VNF does not perform well when it operates far away from the users, e.g., at data centers. These insights help network vendors to more closely monitor the quality of the videos streamed to their customers.

  @inproceedings{info3-inproceedings-2017-3, abstract = {The fast growth of HTTP video streaming is responsible for a huge amount of traffic over the past few years. Due to the variety and popularity of video content, more and more people are watching videos on the smart TV or on mobile devices. As a result, a potential market is emerging for video providers, which can significantly increase their revenues. In order to offer users a good experience, adaptive video streaming has been introduced to adapt the video quality to the network conditions. Nevertheless, it is still difficult for the network operators to assess the actual video quality on the device of the users and therefore they can not react to improve the service on the network. In this work, we propose a Virtual Network Function (VNF) to monitor the Quality of Experience (QoE) for online video service in the network. To conduct the study, on the one hand, we design a VNF monitoring to measure the video quality and estimate the QoE at the client machine. Our function is placed in two locations nearby and far away from the user to analyze the impact of geographical placement of the VNF on its performance. On the other hand, we set up a local testbed to examine the functional operation and measure the actual video buffer from a client web browser directly to validate the accuracy of the function. Our findings show that with respect to function placement, the VNF has high accuracy in estimating the QoE if it is deployed at the edge network close to the user. However, the VNF does not perform well when it operates far away from the users, e.g., at data centers. These insights help network vendors to more closely monitor the quality of the videos streamed to their customers.}, address = {Lisbon, Portugal}, author = {Dinh-Xuan, Lam and Seufert, Michael and Wamser, Florian and Tran-Gia, Phuoc}, booktitle = {1st IFIP/IEEE International Workshop on Quality of Experience Management (QoE-Management)}, keywords = {can}, month = {05}, title = {Study on the Accuracy of QoE Monitoring for HTTP Adaptive Video Streaming Using VNF}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-3 %A Dinh-Xuan, Lam %A Seufert, Michael %A Wamser, Florian %A Tran-Gia, Phuoc %B 1st IFIP/IEEE International Workshop on Quality of Experience Management (QoE-Management) %C Lisbon, Portugal %D 2017 %T Study on the Accuracy of QoE Monitoring for HTTP Adaptive Video Streaming Using VNF %X The fast growth of HTTP video streaming is responsible for a huge amount of traffic over the past few years. Due to the variety and popularity of video content, more and more people are watching videos on the smart TV or on mobile devices. As a result, a potential market is emerging for video providers, which can significantly increase their revenues. In order to offer users a good experience, adaptive video streaming has been introduced to adapt the video quality to the network conditions. Nevertheless, it is still difficult for the network operators to assess the actual video quality on the device of the users and therefore they can not react to improve the service on the network. In this work, we propose a Virtual Network Function (VNF) to monitor the Quality of Experience (QoE) for online video service in the network. To conduct the study, on the one hand, we design a VNF monitoring to measure the video quality and estimate the QoE at the client machine. Our function is placed in two locations nearby and far away from the user to analyze the impact of geographical placement of the VNF on its performance. On the other hand, we set up a local testbed to examine the functional operation and measure the actual video buffer from a client web browser directly to validate the accuracy of the function. Our findings show that with respect to function placement, the VNF has high accuracy in estimating the QoE if it is deployed at the edge network close to the user. However, the VNF does not perform well when it operates far away from the users, e.g., at data centers. These insights help network vendors to more closely monitor the quality of the videos streamed to their customers.
• Automated Decision Making based on Pareto Frontiers in the Context of Service Placement in Networks. Seufert, Michael; Lange, Stanislav; Meixner, Markus. In 29th International Teletraffic Congress (ITC). Genoa, Italy, 2017.
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  Virtualization paradigms like cloud computing, software defined networking (SDN), and network functions virtualization (NFV) provide advantages with respect to aspects like flexibility, costs, and scalability. However, management and orchestration of the resulting networks also introduce new challenges. The placement of services, such as virtual machines~(VMs), virtualized network functions~(VNFs), or SDN controllers, is a multi-objective optimization task that confronts operators with a multitude of possible solutions that are incomparable among each other. The goal of this work is to investigate mechanisms that enable automated decision making between such multi-dimensional solutions. To this end, we investigate techniques from the domain of multi-attribute decision making that aggregate the performance of placements to a single numeric score. A comparison between resulting rankings of placements shows that many techniques produce similar results. Hence, placements that achieve good rankings according to many approaches might be viable candidates in the context of automated decision making. In order to illustrate the functionality of the different scoring mechanisms, we perform a case study on a single network graph and a fixed number of objectives and service instances. Additionally, we present aggregated results from broad evaluations on the Internet Topology Zoo and a larger number of objectives as well as varying numbers of service instances. These allow making more reliable statements about the mechanisms' performance and agreement.

  @inproceedings{info3-article-2017-6, abstract = {Virtualization paradigms like cloud computing, software defined networking (SDN), and network functions virtualization (NFV) provide advantages with respect to aspects like flexibility, costs, and scalability. However, management and orchestration of the resulting networks also introduce new challenges. The placement of services, such as virtual machines (VMs), virtualized network functions (VNFs), or SDN controllers, is a multi-objective optimization task that confronts operators with a multitude of possible solutions that are incomparable among each other. The goal of this work is to investigate mechanisms that enable automated decision making between such multi-dimensional solutions. To this end, we investigate techniques from the domain of multi-attribute decision making that aggregate the performance of placements to a single numeric score. A comparison between resulting rankings of placements shows that many techniques produce similar results. Hence, placements that achieve good rankings according to many approaches might be viable candidates in the context of automated decision making. In order to illustrate the functionality of the different scoring mechanisms, we perform a case study on a single network graph and a fixed number of objectives and service instances. Additionally, we present aggregated results from broad evaluations on the Internet Topology Zoo and a larger number of objectives as well as varying numbers of service instances. These allow making more reliable statements about the mechanisms' performance and agreement.}, address = {Genoa, Italy}, author = {Seufert, Michael and Lange, Stanislav and Meixner, Markus}, booktitle = {29th International Teletraffic Congress (ITC)}, keywords = {can}, month = {09}, title = {Automated Decision Making based on Pareto Frontiers in the Context of Service Placement in Networks}, year = 2017 }

  %0 Conference Paper %1 info3-article-2017-6 %A Seufert, Michael %A Lange, Stanislav %A Meixner, Markus %B 29th International Teletraffic Congress (ITC) %C Genoa, Italy %D 2017 %T Automated Decision Making based on Pareto Frontiers in the Context of Service Placement in Networks %X Virtualization paradigms like cloud computing, software defined networking (SDN), and network functions virtualization (NFV) provide advantages with respect to aspects like flexibility, costs, and scalability. However, management and orchestration of the resulting networks also introduce new challenges. The placement of services, such as virtual machines~(VMs), virtualized network functions~(VNFs), or SDN controllers, is a multi-objective optimization task that confronts operators with a multitude of possible solutions that are incomparable among each other. The goal of this work is to investigate mechanisms that enable automated decision making between such multi-dimensional solutions. To this end, we investigate techniques from the domain of multi-attribute decision making that aggregate the performance of placements to a single numeric score. A comparison between resulting rankings of placements shows that many techniques produce similar results. Hence, placements that achieve good rankings according to many approaches might be viable candidates in the context of automated decision making. In order to illustrate the functionality of the different scoring mechanisms, we perform a case study on a single network graph and a fixed number of objectives and service instances. Additionally, we present aggregated results from broad evaluations on the Internet Topology Zoo and a larger number of objectives as well as varying numbers of service instances. These allow making more reliable statements about the mechanisms' performance and agreement.
• Collecting Subjective Ratings in Enterprise Environments. Borchert, Kathrin; Hirth, Matthias; Zinner, Thomas; Göritz, Anja. In 9th International Conference on Quality of Multimedia Experience (QoMEX). Erfurt, Germany, 2017.
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  @inproceedings{info3-inproceedings-2017-14, address = {Erfurt, Germany}, author = {Borchert, Kathrin and Hirth, Matthias and Zinner, Thomas and Göritz, Anja}, booktitle = {9th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ua-net}, month = {05}, title = {Collecting Subjective Ratings in Enterprise Environments}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-14 %A Borchert, Kathrin %A Hirth, Matthias %A Zinner, Thomas %A Göritz, Anja %B 9th International Conference on Quality of Multimedia Experience (QoMEX) %C Erfurt, Germany %D 2017 %T Collecting Subjective Ratings in Enterprise Environments
• Performance Assessment of Cloud Migrations from Network and Application Point of View. Iffländer, Lukas; Wamser, Florian; Metter, Christopher; Tran-Gia, Phuoc; Kounev, Samuel. In Proceedings of 9th EAI International Conference on Mobile Networks and Management (MONAMI 2017). Melbourne, Australia, 2017.
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  @inproceedings{info3-inproceedings-2017-22, address = {Melbourne, Australia}, author = {Iffländer, Lukas and Wamser, Florian and Metter, Christopher and Tran-Gia, Phuoc and Kounev, Samuel}, booktitle = {Proceedings of 9th EAI International Conference on Mobile Networks and Management (MONAMI 2017)}, keywords = {can}, month = 12, title = {Performance Assessment of Cloud Migrations from Network and Application Point of View}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-22 %A Iffländer, Lukas %A Wamser, Florian %A Metter, Christopher %A Tran-Gia, Phuoc %A Kounev, Samuel %B Proceedings of 9th EAI International Conference on Mobile Networks and Management (MONAMI 2017) %C Melbourne, Australia %D 2017 %T Performance Assessment of Cloud Migrations from Network and Application Point of View
• Performance Evaluation of Selective Flow Monitoring in the ONOS Controller. Nguyen-Ngoc, Anh; Lange, Stanislav; Zinner, Thomas; Seufert, Michael; Tran-Gia, Phuoc; Aerts, Nieke; Hock, David. In 4th International Workshop on Management of SDN and NFV Systems (ManSDN/NFV). Tokio, Japan, 2017.
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  One of the benefits when network operators adopt the Software Defined Networking (SDN) paradigm is the ability to monitor the traffic in the network without an additional network management system. Usually, SDN controllers utilize OpenFlow statistics messages in order to regularly gather information about all flows in the network. However, using the same polling interval for all flows does not take into account the heterogeneity of real world traffic and thus results in an imbalance between monitoring accuracy and control plane overhead. In particular, frequent querying results in a high resource consumption at the controller. This work proposes a Selective Flow Monitoring (SFM) mechanism that allows administrators to classify flows according to their individual requirements in terms of monitoring frequency, e.g., less frequent polling of elephant flows and frequent polling of QoS sensitive VoIP connections. We compare the performance of the SFM mechanism with the default monitoring scheme in a testbed featuring the Open Network Operating System (ONOS) controller. In this context, the CPU utilization of the controller is used as performance indicator. After identifying relevant influence factors like the number of flows and switches in the network, we investigate the viability of the approaches in different scenarios. Finally, we provide guidelines regarding their choice.

  @inproceedings{info3-inproceedings-2017-20, abstract = {One of the benefits when network operators adopt the Software Defined Networking (SDN) paradigm is the ability to monitor the traffic in the network without an additional network management system. Usually, SDN controllers utilize OpenFlow statistics messages in order to regularly gather information about all flows in the network. However, using the same polling interval for all flows does not take into account the heterogeneity of real world traffic and thus results in an imbalance between monitoring accuracy and control plane overhead. In particular, frequent querying results in a high resource consumption at the controller. This work proposes a Selective Flow Monitoring (SFM) mechanism that allows administrators to classify flows according to their individual requirements in terms of monitoring frequency, e.g., less frequent polling of elephant flows and frequent polling of QoS sensitive VoIP connections. We compare the performance of the SFM mechanism with the default monitoring scheme in a testbed featuring the Open Network Operating System (ONOS) controller. In this context, the CPU utilization of the controller is used as performance indicator. After identifying relevant influence factors like the number of flows and switches in the network, we investigate the viability of the approaches in different scenarios. Finally, we provide guidelines regarding their choice.}, address = {Tokio, Japan}, author = {Nguyen-Ngoc, Anh and Lange, Stanislav and Zinner, Thomas and Seufert, Michael and Tran-Gia, Phuoc and Aerts, Nieke and Hock, David}, booktitle = {4th International Workshop on Management of SDN and NFV Systems (ManSDN/NFV)}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Performance Evaluation of Selective Flow Monitoring in the ONOS Controller}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-20 %A Nguyen-Ngoc, Anh %A Lange, Stanislav %A Zinner, Thomas %A Seufert, Michael %A Tran-Gia, Phuoc %A Aerts, Nieke %A Hock, David %B 4th International Workshop on Management of SDN and NFV Systems (ManSDN/NFV) %C Tokio, Japan %D 2017 %T Performance Evaluation of Selective Flow Monitoring in the ONOS Controller %X One of the benefits when network operators adopt the Software Defined Networking (SDN) paradigm is the ability to monitor the traffic in the network without an additional network management system. Usually, SDN controllers utilize OpenFlow statistics messages in order to regularly gather information about all flows in the network. However, using the same polling interval for all flows does not take into account the heterogeneity of real world traffic and thus results in an imbalance between monitoring accuracy and control plane overhead. In particular, frequent querying results in a high resource consumption at the controller. This work proposes a Selective Flow Monitoring (SFM) mechanism that allows administrators to classify flows according to their individual requirements in terms of monitoring frequency, e.g., less frequent polling of elephant flows and frequent polling of QoS sensitive VoIP connections. We compare the performance of the SFM mechanism with the default monitoring scheme in a testbed featuring the Open Network Operating System (ONOS) controller. In this context, the CPU utilization of the controller is used as performance indicator. After identifying relevant influence factors like the number of flows and switches in the network, we investigate the viability of the approaches in different scenarios. Finally, we provide guidelines regarding their choice.
• Applicability and Limitations of a Simple WiFi Hotspot Model for Cities. Seufert, Michael; Moldovan, Christian; Burger, Valentin; Hoßfeld, Tobias. In 13th International Conference on Network and Service Management (CNSM). Tokio, Japan, 2017.
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  Offloading mobile Internet data via WiFi has emerged as an omnipresent trend. WiFi networks are already widely deployed by many private and public institutions (e.g., libraries, cafes, restaurants) but also by commercial services to provide alternative Internet access for their customers and to mitigate the load on mobile networks. Moreover, smart cities start to install WiFi infrastructure for current and future civic services, e.g., based on sensor networks or the Internet of Things. A simple model for the distribution of WiFi hotspots in an urban environment is presented. The hotspot locations are modeled with a uniform distribution of the angle and an exponential distribution of the distance, which is truncated to the city limits. We compare the characteristics of this model in detail to the real distributions. Moreover, we show the applicability and the limitations of this model, and the results suggest that the model can be used in scenarios, which do not require an accurate spatial collocation of the hotspots, such as offloading potential, coverage, or signal strength.

  @inproceedings{info3-inproceedings-2017-19, abstract = {Offloading mobile Internet data via WiFi has emerged as an omnipresent trend. WiFi networks are already widely deployed by many private and public institutions (e.g., libraries, cafes, restaurants) but also by commercial services to provide alternative Internet access for their customers and to mitigate the load on mobile networks. Moreover, smart cities start to install WiFi infrastructure for current and future civic services, e.g., based on sensor networks or the Internet of Things. A simple model for the distribution of WiFi hotspots in an urban environment is presented. The hotspot locations are modeled with a uniform distribution of the angle and an exponential distribution of the distance, which is truncated to the city limits. We compare the characteristics of this model in detail to the real distributions. Moreover, we show the applicability and the limitations of this model, and the results suggest that the model can be used in scenarios, which do not require an accurate spatial collocation of the hotspots, such as offloading potential, coverage, or signal strength.}, address = {Tokio, Japan}, author = {Seufert, Michael and Moldovan, Christian and Burger, Valentin and Hoßfeld, Tobias}, booktitle = {13th International Conference on Network and Service Management (CNSM)}, keywords = {can}, month = 11, title = {Applicability and Limitations of a Simple WiFi Hotspot Model for Cities}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-19 %A Seufert, Michael %A Moldovan, Christian %A Burger, Valentin %A Hoßfeld, Tobias %B 13th International Conference on Network and Service Management (CNSM) %C Tokio, Japan %D 2017 %T Applicability and Limitations of a Simple WiFi Hotspot Model for Cities %X Offloading mobile Internet data via WiFi has emerged as an omnipresent trend. WiFi networks are already widely deployed by many private and public institutions (e.g., libraries, cafes, restaurants) but also by commercial services to provide alternative Internet access for their customers and to mitigate the load on mobile networks. Moreover, smart cities start to install WiFi infrastructure for current and future civic services, e.g., based on sensor networks or the Internet of Things. A simple model for the distribution of WiFi hotspots in an urban environment is presented. The hotspot locations are modeled with a uniform distribution of the angle and an exponential distribution of the distance, which is truncated to the city limits. We compare the characteristics of this model in detail to the real distributions. Moreover, we show the applicability and the limitations of this model, and the results suggest that the model can be used in scenarios, which do not require an accurate spatial collocation of the hotspots, such as offloading potential, coverage, or signal strength.
• Keep Calm and Don’t Switch: About the Relationship Between Switches and Quality in HAS. Moldovan, Christian; Hagn, Korbinian; Sieber, Christian; Kellerer, Wolfgang; Hoßfeld, Tobias. In 29th International Teletraffic Congress (ITC 29), p. 6. Genoa, Italy, 2017.
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  Video streaming has established itself as the main method to consume multimedia content on the Internet. The most widespread technique is HTTP Adaptive Streaming which is used by large video service platforms such as YouTube and Netflix. In order to guarantee a high QoE, different adaptation strategies have been developed that lead to different video playout patterns. While some strategies may be more aggressive than others and often adapt the video quality, it is not clear which strategy is the best. In this paper, we want to identify the trade-off between the av- erage video quality and switches in the quality during playout. We do this with a user-centric view and try to optimize the adaptation depending on the user preference with a quadratic program. This work allows us to put existing and future video adaptation algorithms in perspective with respect to user preferences. Our results show that the video quality can already be increased greatly by allowing few switches while more switches lead to diminishing gains. This is a novel discovery that is important for user-centric QoE-management which is of high interest for ISPs and video service providers.

  @inproceedings{info3-inproceedings-2017-26, abstract = {Video streaming has established itself as the main method to consume multimedia content on the Internet. The most widespread technique is HTTP Adaptive Streaming which is used by large video service platforms such as YouTube and Netflix. In order to guarantee a high QoE, different adaptation strategies have been developed that lead to different video playout patterns. While some strategies may be more aggressive than others and often adapt the video quality, it is not clear which strategy is the best. In this paper, we want to identify the trade-off between the av- erage video quality and switches in the quality during playout. We do this with a user-centric view and try to optimize the adaptation depending on the user preference with a quadratic program. This work allows us to put existing and future video adaptation algorithms in perspective with respect to user preferences. Our results show that the video quality can already be increased greatly by allowing few switches while more switches lead to diminishing gains. This is a novel discovery that is important for user-centric QoE-management which is of high interest for ISPs and video service providers.}, address = {Genoa, Italy}, author = {Moldovan, Christian and Hagn, Korbinian and Sieber, Christian and Kellerer, Wolfgang and Hoßfeld, Tobias}, booktitle = {29th International Teletraffic Congress (ITC 29)}, keywords = {video-quality}, month = {09}, pages = 6, title = {Keep Calm and Don’t Switch: About the Relationship Between Switches and Quality in HAS}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-26 %A Moldovan, Christian %A Hagn, Korbinian %A Sieber, Christian %A Kellerer, Wolfgang %A Hoßfeld, Tobias %B 29th International Teletraffic Congress (ITC 29) %C Genoa, Italy %D 2017 %P 6 %T Keep Calm and Don’t Switch: About the Relationship Between Switches and Quality in HAS %X Video streaming has established itself as the main method to consume multimedia content on the Internet. The most widespread technique is HTTP Adaptive Streaming which is used by large video service platforms such as YouTube and Netflix. In order to guarantee a high QoE, different adaptation strategies have been developed that lead to different video playout patterns. While some strategies may be more aggressive than others and often adapt the video quality, it is not clear which strategy is the best. In this paper, we want to identify the trade-off between the av- erage video quality and switches in the quality during playout. We do this with a user-centric view and try to optimize the adaptation depending on the user preference with a quadratic program. This work allows us to put existing and future video adaptation algorithms in perspective with respect to user preferences. Our results show that the video quality can already be increased greatly by allowing few switches while more switches lead to diminishing gains. This is a novel discovery that is important for user-centric QoE-management which is of high interest for ISPs and video service providers.
• Performance Evaluation of Video Streaming Service Chains in Softwarized 5G Networks with Task Graph Reduction. Loh, Frank; Burger, Valentin; Wamser, Florian; Tran-Gia, Phuoc; Schembra, Giovanni; Rametta, Corrado. In 29th International Teletraffic Congress (ITC). 2017.
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  @inproceedings{info3-inproceedings-2017-18, author = {Loh, Frank and Burger, Valentin and Wamser, Florian and Tran-Gia, Phuoc and Schembra, Giovanni and Rametta, Corrado}, booktitle = {29th International Teletraffic Congress (ITC)}, keywords = {can}, month = {09}, title = {Performance Evaluation of Video Streaming Service Chains in Softwarized 5G Networks with Task Graph Reduction}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-18 %A Loh, Frank %A Burger, Valentin %A Wamser, Florian %A Tran-Gia, Phuoc %A Schembra, Giovanni %A Rametta, Corrado %B 29th International Teletraffic Congress (ITC) %D 2017 %T Performance Evaluation of Video Streaming Service Chains in Softwarized 5G Networks with Task Graph Reduction
• A Multi-Objective Heuristic for the Optimization of Virtual Network Function Chain Placement. Lange, Stanislav; Grigorjew, Alexej; Zinner, Thomas; Tran-Gia, Phuoc; Jarschel, Michael. In 29th International Teletraffic Congress (ITC). 2017.
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  @inproceedings{info3-inproceedings-2017-16, author = {Lange, Stanislav and Grigorjew, Alexej and Zinner, Thomas and Tran-Gia, Phuoc and Jarschel, Michael}, booktitle = {29th International Teletraffic Congress (ITC)}, keywords = {sendate}, month = {09}, title = {A Multi-Objective Heuristic for the Optimization of Virtual Network Function Chain Placement}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-16 %A Lange, Stanislav %A Grigorjew, Alexej %A Zinner, Thomas %A Tran-Gia, Phuoc %A Jarschel, Michael %B 29th International Teletraffic Congress (ITC) %D 2017 %T A Multi-Objective Heuristic for the Optimization of Virtual Network Function Chain Placement
• Saving Bandwidth by Limiting the Buffer Size in HTTP Adaptive Streaming. Surminski, Sebastian; Moldovan, Christian; Hoßfeld, Tobias. In MMBnet 2017 Proceedings of the 9th GI/ITG Workshop. Hamburg, Germany, 2017.
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  Video streaming is one of the most bandwidth-intensive applications on the Internet. In HTTP adaptive video streaming the video quality is selected according to the available bandwidth. To compensate bandwidth fluctuations, players use a buffer in order to ensure a smooth video output. On one hand, if the buffer runs empty, the video playback stops, which users experience as negative. On the other hand, if the user aborts video playback, the video in the buffer was unnecessarily transmitted, hence this bandwidth was wasted. In this paper, we present a study in which we investigate the behavior of two video players and different buffer configurations in real-world bandwidth scenarios. Thereby, we focus on the dimensioning of the buffer size and the tradeoff between wasted bandwidth and the playback quality

  @inproceedings{info3-inproceedings-2017-27, abstract = {Video streaming is one of the most bandwidth-intensive applications on the Internet. In HTTP adaptive video streaming the video quality is selected according to the available bandwidth. To compensate bandwidth fluctuations, players use a buffer in order to ensure a smooth video output. On one hand, if the buffer runs empty, the video playback stops, which users experience as negative. On the other hand, if the user aborts video playback, the video in the buffer was unnecessarily transmitted, hence this bandwidth was wasted. In this paper, we present a study in which we investigate the behavior of two video players and different buffer configurations in real-world bandwidth scenarios. Thereby, we focus on the dimensioning of the buffer size and the tradeoff between wasted bandwidth and the playback quality}, address = {Hamburg, Germany}, author = {Surminski, Sebastian and Moldovan, Christian and Hoßfeld, Tobias}, booktitle = {MMBnet 2017 Proceedings of the 9th GI/ITG Workshop}, keywords = {dfg-sdn}, month = {09}, title = {Saving Bandwidth by Limiting the Buffer Size in HTTP Adaptive Streaming}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-27 %A Surminski, Sebastian %A Moldovan, Christian %A Hoßfeld, Tobias %B MMBnet 2017 Proceedings of the 9th GI/ITG Workshop %C Hamburg, Germany %D 2017 %T Saving Bandwidth by Limiting the Buffer Size in HTTP Adaptive Streaming %X Video streaming is one of the most bandwidth-intensive applications on the Internet. In HTTP adaptive video streaming the video quality is selected according to the available bandwidth. To compensate bandwidth fluctuations, players use a buffer in order to ensure a smooth video output. On one hand, if the buffer runs empty, the video playback stops, which users experience as negative. On the other hand, if the user aborts video playback, the video in the buffer was unnecessarily transmitted, hence this bandwidth was wasted. In this paper, we present a study in which we investigate the behavior of two video players and different buffer configurations in real-world bandwidth scenarios. Thereby, we focus on the dimensioning of the buffer size and the tradeoff between wasted bandwidth and the playback quality
• Designing a Survey Tool for Monitoring Enterprise QoE. Borchert, Kathrin; Hirth, Matthias; Zinner, Thomas; Göritz, Anja. In ACM SIGCOMM Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE). Los Angeles, CA, USA, 2017.
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  Enterprise applications like SAP are part of the day-to-day work of a large number of employees. Similar to many modern applications, enterprise applications are often implemented in a distributed fashion and consequently suffer from network degradations resulting in impairments like increased loading delays. While the influence of these impairments on the perceived quality of users is well researched for consumer applications and network services, the impact of these impairments in a business environment is still unclear. To address this gap we develop a non-intrusive software tool for continuously collecting subjective ratings on the performance of an enterprise application from a large crowd of employees. Based on the feedback from a company and results from two initial field studies we discuss the specific challenges when assessing the perceived quality of employees during regular working hours and point our further research directions.

  @inproceedings{info3-inproceedings-2017-13, abstract = {Enterprise applications like SAP are part of the day-to-day work of a large number of employees. Similar to many modern applications, enterprise applications are often implemented in a distributed fashion and consequently suffer from network degradations resulting in impairments like increased loading delays. While the influence of these impairments on the perceived quality of users is well researched for consumer applications and network services, the impact of these impairments in a business environment is still unclear. To address this gap we develop a non-intrusive software tool for continuously collecting subjective ratings on the performance of an enterprise application from a large crowd of employees. Based on the feedback from a company and results from two initial field studies we discuss the specific challenges when assessing the perceived quality of employees during regular working hours and point our further research directions.}, address = {Los Angeles, CA, USA}, author = {Borchert, Kathrin and Hirth, Matthias and Zinner, Thomas and Göritz, Anja}, booktitle = {ACM SIGCOMM Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE)}, keywords = {ua-net}, month = {08}, title = {Designing a Survey Tool for Monitoring Enterprise QoE}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-13 %A Borchert, Kathrin %A Hirth, Matthias %A Zinner, Thomas %A Göritz, Anja %B ACM SIGCOMM Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE) %C Los Angeles, CA, USA %D 2017 %T Designing a Survey Tool for Monitoring Enterprise QoE %X Enterprise applications like SAP are part of the day-to-day work of a large number of employees. Similar to many modern applications, enterprise applications are often implemented in a distributed fashion and consequently suffer from network degradations resulting in impairments like increased loading delays. While the influence of these impairments on the perceived quality of users is well researched for consumer applications and network services, the impact of these impairments in a business environment is still unclear. To address this gap we develop a non-intrusive software tool for continuously collecting subjective ratings on the performance of an enterprise application from a large crowd of employees. Based on the feedback from a company and results from two initial field studies we discuss the specific challenges when assessing the perceived quality of employees during regular working hours and point our further research directions.
• Server and Content Selection for MPEG DASH Video Streaming with Client Information. Wamser, Florian; Höfner, Steffen; Seufert, Michael; Tran-Gia, Phuoc. In ACM SIGCOMM Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE). Los Angeles, CA, USA, 2017.
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  In HTTP adaptive streaming (HAS), such as MPEG DASH, the video is split into chunks and is available in different quality levels. If the video chunks are stored or cached on different servers to deal with the high load in the network and the Quality of Experience (QoE) requirements of the users, the problem of content selection arises. In this paper, we evaluate client-side algorithms for dynamically selecting an appropriate content server during DASH video streaming. We present three algorithms with which the DASH client itself can determine the most appropriate server based on client-specific metrics, like actual latency or bandwidth to the content servers. We evaluate and discuss the proposed algorithms with respect to the resulting DASH streaming behavior in terms of buffer levels and quality level selection.

  @inproceedings{info3-article-2017-3, abstract = {In HTTP adaptive streaming (HAS), such as MPEG DASH, the video is split into chunks and is available in different quality levels. If the video chunks are stored or cached on different servers to deal with the high load in the network and the Quality of Experience (QoE) requirements of the users, the problem of content selection arises. In this paper, we evaluate client-side algorithms for dynamically selecting an appropriate content server during DASH video streaming. We present three algorithms with which the DASH client itself can determine the most appropriate server based on client-specific metrics, like actual latency or bandwidth to the content servers. We evaluate and discuss the proposed algorithms with respect to the resulting DASH streaming behavior in terms of buffer levels and quality level selection.}, address = {Los Angeles, CA, USA}, author = {Wamser, Florian and Höfner, Steffen and Seufert, Michael and Tran-Gia, Phuoc}, booktitle = {ACM SIGCOMM Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE)}, keywords = {can}, month = {08}, title = {Server and Content Selection for MPEG DASH Video Streaming with Client Information}, year = 2017 }

  %0 Conference Paper %1 info3-article-2017-3 %A Wamser, Florian %A Höfner, Steffen %A Seufert, Michael %A Tran-Gia, Phuoc %B ACM SIGCOMM Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE) %C Los Angeles, CA, USA %D 2017 %T Server and Content Selection for MPEG DASH Video Streaming with Client Information %X In HTTP adaptive streaming (HAS), such as MPEG DASH, the video is split into chunks and is available in different quality levels. If the video chunks are stored or cached on different servers to deal with the high load in the network and the Quality of Experience (QoE) requirements of the users, the problem of content selection arises. In this paper, we evaluate client-side algorithms for dynamically selecting an appropriate content server during DASH video streaming. We present three algorithms with which the DASH client itself can determine the most appropriate server based on client-specific metrics, like actual latency or bandwidth to the content servers. We evaluate and discuss the proposed algorithms with respect to the resulting DASH streaming behavior in terms of buffer levels and quality level selection.
• Impact of Task Recommendation Systems in Crowdsourcing Platforms. Borchert, Kathrin; Hirth, Matthias; Schnitzer, Steffen; Rensing, Christoph. In Workshop on Responsible Recommendation at RecSys 2017. Como, Italy, 2017.
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  @inproceedings{info3-inproceedings-2017-17, address = {Como, Italy}, author = {Borchert, Kathrin and Hirth, Matthias and Schnitzer, Steffen and Rensing, Christoph}, booktitle = {Workshop on Responsible Recommendation at RecSys 2017}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Impact of Task Recommendation Systems in Crowdsourcing Platforms}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-17 %A Borchert, Kathrin %A Hirth, Matthias %A Schnitzer, Steffen %A Rensing, Christoph %B Workshop on Responsible Recommendation at RecSys 2017 %C Como, Italy %D 2017 %T Impact of Task Recommendation Systems in Crowdsourcing Platforms
• Concept and Implementation of Video QoE Measurements in a Mobile Broadband Testbed. Schwind, Anika; Seufert, Michael; Alay, Özgü; Casas, Pedro; Tran-Gia, Phuoc; Wamser, Florian. In IEEE/IFIP Workshop on Mobile Network Measurement (MNM’17). Dublin, Ireland, 2017.
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  The MONROE testbed enables the objective performance assessment of MBB networks from the end-user perspective, using highly distributed measurements from fixed and mobile nodes. To quantify the performance of MBB networks for popular Internet services from a user-centric perspective, dedicated tools are needed. In this paper we extend the MONROE testbed to the Quality of Experience (QoE) domain, presenting the design and implementation of a QoE-capable measurement tool for YouTube video streaming. The measurement concept is based on emulating a virtual end-user device requesting video streams, which are then monitored at the network and application layers, on the basis of QoE-relevant features. The initial measurements conducted in the MONROE testbed and reported in this paper demonstrate the applicability of the implemented measurement concept.

  @inproceedings{info3-inproceedings-2017-15, abstract = {The MONROE testbed enables the objective performance assessment of MBB networks from the end-user perspective, using highly distributed measurements from fixed and mobile nodes. To quantify the performance of MBB networks for popular Internet services from a user-centric perspective, dedicated tools are needed. In this paper we extend the MONROE testbed to the Quality of Experience (QoE) domain, presenting the design and implementation of a QoE-capable measurement tool for YouTube video streaming. The measurement concept is based on emulating a virtual end-user device requesting video streams, which are then monitored at the network and application layers, on the basis of QoE-relevant features. The initial measurements conducted in the MONROE testbed and reported in this paper demonstrate the applicability of the implemented measurement concept.}, address = {Dublin, Ireland}, author = {Schwind, Anika and Seufert, Michael and Alay, Özgü and Casas, Pedro and Tran-Gia, Phuoc and Wamser, Florian}, booktitle = {IEEE/IFIP Workshop on Mobile Network Measurement (MNM’17)}, keywords = {can}, month = {06}, title = {Concept and Implementation of Video QoE Measurements in a Mobile Broadband Testbed}, year = 2017 }

  %0 Conference Paper %1 info3-inproceedings-2017-15 %A Schwind, Anika %A Seufert, Michael %A Alay, Özgü %A Casas, Pedro %A Tran-Gia, Phuoc %A Wamser, Florian %B IEEE/IFIP Workshop on Mobile Network Measurement (MNM’17) %C Dublin, Ireland %D 2017 %T Concept and Implementation of Video QoE Measurements in a Mobile Broadband Testbed %X The MONROE testbed enables the objective performance assessment of MBB networks from the end-user perspective, using highly distributed measurements from fixed and mobile nodes. To quantify the performance of MBB networks for popular Internet services from a user-centric perspective, dedicated tools are needed. In this paper we extend the MONROE testbed to the Quality of Experience (QoE) domain, presenting the design and implementation of a QoE-capable measurement tool for YouTube video streaming. The measurement concept is based on emulating a virtual end-user device requesting video streams, which are then monitored at the network and application layers, on the basis of QoE-relevant features. The initial measurements conducted in the MONROE testbed and reported in this paper demonstrate the applicability of the implemented measurement concept.

• Group-based Communication in WhatsApp. Seufert, Michael; Hoßfeld, Tobias; Schwind, Anika; Burger, Valentin; Tran-Gia, Phuoc. In 1st IFIP Internet of People Workshop (IoP). Vienna, Austria, 2016.
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  WhatsApp is a very popular mobile messaging application, which dominates today’s mobile communication. Especially the feature of group chats contributes to its success and changes the way people communicate. The group-based communication paradigm is investigated in this work, particularly focusing on the usage of WhatsApp, communication in group chats, and implications on mobile network traffic.

  @inproceedings{info3-inproceedings-2016-1, abstract = {WhatsApp is a very popular mobile messaging application, which dominates today’s mobile communication. Especially the feature of group chats contributes to its success and changes the way people communicate. The group-based communication paradigm is investigated in this work, particularly focusing on the usage of WhatsApp, communication in group chats, and implications on mobile network traffic.}, address = {Vienna, Austria}, author = {Seufert, Michael and Hoßfeld, Tobias and Schwind, Anika and Burger, Valentin and Tran-Gia, Phuoc}, booktitle = {1st IFIP Internet of People Workshop (IoP)}, keywords = {can}, month = {05}, title = {Group-based Communication in WhatsApp}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-1 %A Seufert, Michael %A Hoßfeld, Tobias %A Schwind, Anika %A Burger, Valentin %A Tran-Gia, Phuoc %B 1st IFIP Internet of People Workshop (IoP) %C Vienna, Austria %D 2016 %T Group-based Communication in WhatsApp %X WhatsApp is a very popular mobile messaging application, which dominates today’s mobile communication. Especially the feature of group chats contributes to its success and changes the way people communicate. The group-based communication paradigm is investigated in this work, particularly focusing on the usage of WhatsApp, communication in group chats, and implications on mobile network traffic.
• Performance Evaluation Mechanisms for FlowMod Message Processing in OpenFlow Switches. Nguyen-Ngoc, Anh; Lange, Stanislav; Gebert, Steffen; Zinner, Thomas; Tran-Gia, Phuoc; Jarschel, Michael. In IEEE Sixth International Conference on Communications and Electronics. Ha Long City, Vietnam, 2016.
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  Network operators can benefit in terms of flexibility, cost, and vendor-independence when adopting the Software Defined Networking (SDN) paradigm. In many scenarios, the SDN controller orders the installation of new flow table entries in the switches it manages. Since such operations are handled in the slow path of the switches, the corresponding processing times constitute an important performance indicator for switches. This work focuses on a comparison of two mechanisms for evaluating the performance of OpenFlow switches with respect to the processing time of FlowMod messages. These mechanisms are characterized by different degrees of accuracy, cost, complexity, and the capability of performing measurements at run time. The first mechanism is based on the Spirent C1 dedicated testing platform, while the other uses a software module for the OpenDaylight controller. We assess their capabilities with respect to the abovementioned characteristics and quantify their accuracy by means of wiretaps that provide a ground truth regarding the measured processing times. By using three different switches in the experiments, it is possible to distinguish between hardware specific side-effects and general phenomena.

  @inproceedings{info3-inproceedings-2016-7, abstract = {Network operators can benefit in terms of flexibility, cost, and vendor-independence when adopting the Software Defined Networking (SDN) paradigm. In many scenarios, the SDN controller orders the installation of new flow table entries in the switches it manages. Since such operations are handled in the slow path of the switches, the corresponding processing times constitute an important performance indicator for switches. This work focuses on a comparison of two mechanisms for evaluating the performance of OpenFlow switches with respect to the processing time of FlowMod messages. These mechanisms are characterized by different degrees of accuracy, cost, complexity, and the capability of performing measurements at run time. The first mechanism is based on the Spirent C1 dedicated testing platform, while the other uses a software module for the OpenDaylight controller. We assess their capabilities with respect to the abovementioned characteristics and quantify their accuracy by means of wiretaps that provide a ground truth regarding the measured processing times. By using three different switches in the experiments, it is possible to distinguish between hardware specific side-effects and general phenomena.}, address = {Ha Long City, Vietnam}, author = {Nguyen-Ngoc, Anh and Lange, Stanislav and Gebert, Steffen and Zinner, Thomas and Tran-Gia, Phuoc and Jarschel, Michael}, booktitle = {IEEE Sixth International Conference on Communications and Electronics}, keywords = {sendate}, month = {07}, title = {Performance Evaluation Mechanisms for FlowMod Message Processing in OpenFlow Switches}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-7 %A Nguyen-Ngoc, Anh %A Lange, Stanislav %A Gebert, Steffen %A Zinner, Thomas %A Tran-Gia, Phuoc %A Jarschel, Michael %B IEEE Sixth International Conference on Communications and Electronics %C Ha Long City, Vietnam %D 2016 %T Performance Evaluation Mechanisms for FlowMod Message Processing in OpenFlow Switches %X Network operators can benefit in terms of flexibility, cost, and vendor-independence when adopting the Software Defined Networking (SDN) paradigm. In many scenarios, the SDN controller orders the installation of new flow table entries in the switches it manages. Since such operations are handled in the slow path of the switches, the corresponding processing times constitute an important performance indicator for switches. This work focuses on a comparison of two mechanisms for evaluating the performance of OpenFlow switches with respect to the processing time of FlowMod messages. These mechanisms are characterized by different degrees of accuracy, cost, complexity, and the capability of performing measurements at run time. The first mechanism is based on the Spirent C1 dedicated testing platform, while the other uses a software module for the OpenDaylight controller. We assess their capabilities with respect to the abovementioned characteristics and quantify their accuracy by means of wiretaps that provide a ground truth regarding the measured processing times. By using three different switches in the experiments, it is possible to distinguish between hardware specific side-effects and general phenomena.
• ERWIN - Enabling the Reproducible Investigation of WaItiNg Times for Arbitrary Workflows. Zinner, Thomas; Hirth, Matthias; Fischer, Valentin; Hohlfeld, Oliver. In 8th International Conference on Quality of Multimedia Experiene (QoMEX). Lisbon, Portugal, 2016.
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  Delay effects can impact the Quality of Experience of interactive systems, which motivates research assessing delay impairments, mostly for web based systems. Current studies follow individual methodologies and typically assesses individual and custom-made web pages, whose construction requires expert knowledge in web technologies. A range of native, non-web applications cannot be easily modified for delay studies. Thus, a generalized methodology for assessing delay impacts for a broad range of applications that is assessable to researchers without (web) development expertise is still missing. This paper con- tributes to this open problem by i) presenting a new methodology for reproducible delay assessments in a broad class of (web-based) systems and ii) presenting an open-source implementation to be used by the community. This methodology particularly aims at making delay assessment available to a broad range of researchers by avoiding programming skills and thus by lowering the barrier for setting-up delay assessments.

  @inproceedings{info3-inproceedings-2016-6, abstract = {Delay effects can impact the Quality of Experience of interactive systems, which motivates research assessing delay impairments, mostly for web based systems. Current studies follow individual methodologies and typically assesses individual and custom-made web pages, whose construction requires expert knowledge in web technologies. A range of native, non-web applications cannot be easily modified for delay studies. Thus, a generalized methodology for assessing delay impacts for a broad range of applications that is assessable to researchers without (web) development expertise is still missing. This paper con- tributes to this open problem by i) presenting a new methodology for reproducible delay assessments in a broad class of (web-based) systems and ii) presenting an open-source implementation to be used by the community. This methodology particularly aims at making delay assessment available to a broad range of researchers by avoiding programming skills and thus by lowering the barrier for setting-up delay assessments.}, address = {Lisbon, Portugal}, author = {Zinner, Thomas and Hirth, Matthias and Fischer, Valentin and Hohlfeld, Oliver}, booktitle = {8th International Conference on Quality of Multimedia Experiene (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {ERWIN - Enabling the Reproducible Investigation of WaItiNg Times for Arbitrary Workflows}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-6 %A Zinner, Thomas %A Hirth, Matthias %A Fischer, Valentin %A Hohlfeld, Oliver %B 8th International Conference on Quality of Multimedia Experiene (QoMEX) %C Lisbon, Portugal %D 2016 %T ERWIN - Enabling the Reproducible Investigation of WaItiNg Times for Arbitrary Workflows %X Delay effects can impact the Quality of Experience of interactive systems, which motivates research assessing delay impairments, mostly for web based systems. Current studies follow individual methodologies and typically assesses individual and custom-made web pages, whose construction requires expert knowledge in web technologies. A range of native, non-web applications cannot be easily modified for delay studies. Thus, a generalized methodology for assessing delay impacts for a broad range of applications that is assessable to researchers without (web) development expertise is still missing. This paper con- tributes to this open problem by i) presenting a new methodology for reproducible delay assessments in a broad class of (web-based) systems and ii) presenting an open-source implementation to be used by the community. This methodology particularly aims at making delay assessment available to a broad range of researchers by avoiding programming skills and thus by lowering the barrier for setting-up delay assessments.
• Impact of Test Condition Selection in Adaptive Crowdsourcing Studies on Subjective Quality. Seufert, Michael; Zach, Ondrej; Hoßfeld, Tobias; Slanina, Martin; Tran-Gia, Phuoc. In 8th International Conference on Quality of Multimedia Experience (QoMEX). Lisbon, Portugal, 2016.
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  Adaptive crowdsourcing is a new approach to crowdsourced Quality of Experience (QoE) studies, which aims to improve the certainty of resulting QoE models by adaptively distributing a fixed budget of user ratings to the test conditions. The main idea of the adaptation is to dynamically allocate the next rating to a condition, for which the submitted ratings so far show a low certainty. This paper investigates the effects of statistical adaptation on the distribution of ratings and the goodness of the resulting QoE models. Thereby, it gives methodological advice how to select test conditions for future crowdsourced QoE studies.

  @inproceedings{info3-inproceedings-2016-10, abstract = {Adaptive crowdsourcing is a new approach to crowdsourced Quality of Experience (QoE) studies, which aims to improve the certainty of resulting QoE models by adaptively distributing a fixed budget of user ratings to the test conditions. The main idea of the adaptation is to dynamically allocate the next rating to a condition, for which the submitted ratings so far show a low certainty. This paper investigates the effects of statistical adaptation on the distribution of ratings and the goodness of the resulting QoE models. Thereby, it gives methodological advice how to select test conditions for future crowdsourced QoE studies.}, address = {Lisbon, Portugal}, author = {Seufert, Michael and Zach, Ondrej and Hoßfeld, Tobias and Slanina, Martin and Tran-Gia, Phuoc}, booktitle = {8th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {can}, month = {06}, title = {Impact of Test Condition Selection in Adaptive Crowdsourcing Studies on Subjective Quality}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-10 %A Seufert, Michael %A Zach, Ondrej %A Hoßfeld, Tobias %A Slanina, Martin %A Tran-Gia, Phuoc %B 8th International Conference on Quality of Multimedia Experience (QoMEX) %C Lisbon, Portugal %D 2016 %T Impact of Test Condition Selection in Adaptive Crowdsourcing Studies on Subjective Quality %X Adaptive crowdsourcing is a new approach to crowdsourced Quality of Experience (QoE) studies, which aims to improve the certainty of resulting QoE models by adaptively distributing a fixed budget of user ratings to the test conditions. The main idea of the adaptation is to dynamically allocate the next rating to a condition, for which the submitted ratings so far show a low certainty. This paper investigates the effects of statistical adaptation on the distribution of ratings and the goodness of the resulting QoE models. Thereby, it gives methodological advice how to select test conditions for future crowdsourced QoE studies.
• Load Dynamics of a Multiplayer Online Battle Area and Simulative Assessment of Edge Server Placements. Burger, Valentin; Frances Pajo, Jane; Sanchez, Odnan Ref; Seufert, Michael; Schwartz, Christian; Wamser, Florian; Davoli, Franco; Tran-Gia, Phuoc. In ACM Multimedia Systems Conference (MMSys). Klagenfurt, Austria, 2016.
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  Free-to-play models, streaming of games and eSports are reasons for online gaming to grow in popularity recently. On the forefront are multiplayer online battle arenas, which gain high popularity by introducing a competitive format that is easy to access and requires cooperation and team play. These games highly rely on fast reaction of the players, which makes latency the key performance indicator of such applications. To obtain low latency, this paper proposes moving game servers close to players towards the edge of the network. The performance of such mechanism highly depends on the geographic distribution of players. By analyzing match histories and statistics, we develop models for the arrival process and location of game requests. This allows us to evaluate the performance of edge server resource migration policies in an event based simulation. Our results show that a high number of edge servers is preferable compared to few larger edge servers to reduce the latency of players. This supports approaches that allow deploying virtual server instances in the back-haul.

  @inproceedings{info3-inproceedings-2016-2, abstract = {Free-to-play models, streaming of games and eSports are reasons for online gaming to grow in popularity recently. On the forefront are multiplayer online battle arenas, which gain high popularity by introducing a competitive format that is easy to access and requires cooperation and team play. These games highly rely on fast reaction of the players, which makes latency the key performance indicator of such applications. To obtain low latency, this paper proposes moving game servers close to players towards the edge of the network. The performance of such mechanism highly depends on the geographic distribution of players. By analyzing match histories and statistics, we develop models for the arrival process and location of game requests. This allows us to evaluate the performance of edge server resource migration policies in an event based simulation. Our results show that a high number of edge servers is preferable compared to few larger edge servers to reduce the latency of players. This supports approaches that allow deploying virtual server instances in the back-haul.}, address = {Klagenfurt, Austria}, author = {Burger, Valentin and Frances Pajo, Jane and Sanchez, Odnan Ref and Seufert, Michael and Schwartz, Christian and Wamser, Florian and Davoli, Franco and Tran-Gia, Phuoc}, booktitle = {ACM Multimedia Systems Conference (MMSys)}, keywords = {can}, month = {05}, title = {Load Dynamics of a Multiplayer Online Battle Area and Simulative Assessment of Edge Server Placements}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-2 %A Burger, Valentin %A Frances Pajo, Jane %A Sanchez, Odnan Ref %A Seufert, Michael %A Schwartz, Christian %A Wamser, Florian %A Davoli, Franco %A Tran-Gia, Phuoc %B ACM Multimedia Systems Conference (MMSys) %C Klagenfurt, Austria %D 2016 %T Load Dynamics of a Multiplayer Online Battle Area and Simulative Assessment of Edge Server Placements %X Free-to-play models, streaming of games and eSports are reasons for online gaming to grow in popularity recently. On the forefront are multiplayer online battle arenas, which gain high popularity by introducing a competitive format that is easy to access and requires cooperation and team play. These games highly rely on fast reaction of the players, which makes latency the key performance indicator of such applications. To obtain low latency, this paper proposes moving game servers close to players towards the edge of the network. The performance of such mechanism highly depends on the geographic distribution of players. By analyzing match histories and statistics, we develop models for the arrival process and location of game requests. This allows us to evaluate the performance of edge server resource migration policies in an event based simulation. Our results show that a high number of edge servers is preferable compared to few larger edge servers to reduce the latency of players. This supports approaches that allow deploying virtual server instances in the back-haul.
• Design and Experimental Evaluation of Network-assisted Strategies for HTTP Adaptive Video Streaming. Cofano, Guiseppe; De Cicco, Luca; Zinner, Thomas; Nguyen-Ngoc, Anh; Tran-Gia, Phuoc; Mascolo, Saverio. In Best Student Paper Award, ACM Multimedia Systems Conference (MMSys). Klagenfurt, Austria, 2016.
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  In this paper we investigate several network-assisted streaming approaches which rely on active cooperation between video streaming applications and the network. We build a Video Control Plane which enforces Video Quality Fairness among concurrent video flows generated by heterogeneous client devices. To the purpose, a max-min fairness optimization problem is solved at run-time. We compare two approaches to actuate the optimal solution in an SDN network: the first one allocating network bandwidth slices to video flows, the second one guiding video players in the video bitrate selection. Performance is assessed through several QoE-related metrics, such as Video Quality Fairness, video quality, and switching frequency. The impact of client-side adaptation algorithms is also investigated.

  @inproceedings{info3-inproceedings-2016-3, abstract = {In this paper we investigate several network-assisted streaming approaches which rely on active cooperation between video streaming applications and the network. We build a Video Control Plane which enforces Video Quality Fairness among concurrent video flows generated by heterogeneous client devices. To the purpose, a max-min fairness optimization problem is solved at run-time. We compare two approaches to actuate the optimal solution in an SDN network: the first one allocating network bandwidth slices to video flows, the second one guiding video players in the video bitrate selection. Performance is assessed through several QoE-related metrics, such as Video Quality Fairness, video quality, and switching frequency. The impact of client-side adaptation algorithms is also investigated.}, address = {Klagenfurt, Austria}, author = {Cofano, Guiseppe and De Cicco, Luca and Zinner, Thomas and Nguyen-Ngoc, Anh and Tran-Gia, Phuoc and Mascolo, Saverio}, booktitle = {Best Student Paper Award, ACM Multimedia Systems Conference (MMSys)}, keywords = {Paper}, month = {05}, title = {Design and Experimental Evaluation of Network-assisted Strategies for HTTP Adaptive Video Streaming}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-3 %A Cofano, Guiseppe %A De Cicco, Luca %A Zinner, Thomas %A Nguyen-Ngoc, Anh %A Tran-Gia, Phuoc %A Mascolo, Saverio %B Best Student Paper Award, ACM Multimedia Systems Conference (MMSys) %C Klagenfurt, Austria %D 2016 %T Design and Experimental Evaluation of Network-assisted Strategies for HTTP Adaptive Video Streaming %X In this paper we investigate several network-assisted streaming approaches which rely on active cooperation between video streaming applications and the network. We build a Video Control Plane which enforces Video Quality Fairness among concurrent video flows generated by heterogeneous client devices. To the purpose, a max-min fairness optimization problem is solved at run-time. We compare two approaches to actuate the optimal solution in an SDN network: the first one allocating network bandwidth slices to video flows, the second one guiding video players in the video bitrate selection. Performance is assessed through several QoE-related metrics, such as Video Quality Fairness, video quality, and switching frequency. The impact of client-side adaptation algorithms is also investigated.
• QoE Aware Placement of Content in Edge Networks on the Example of a Photo Album Cloud Service. Dinh-Xuan, Lam; Seufert, Michael; Wamser, Florian; Tran-Gia, Phuoc. In IEEE 6th International Conference on Communications and Electronics (ICCE). Ha Long, Vietnam, 2016.
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  The paradigm of Software as a Service has gained great achievements in the last decade. By transferring computation and storage to the cloud and migrating services to the edge network, users benefit from using demanding services on lightweight devices. However, the user perceived quality of experience (QoE) for these services is facing the challenges of network impairments and the accessibility of users. Unlike a typical PC-based software, the cloud provides users a location-aware, flexible placement of resource for a cost effective service. The geographical placement of content is therefore one of the key factors that affects the user's satisfaction. The closer the content to the user geographically is, the faster it will be delivered to the user that will also increase the user perceived QoE. In this work, we estimate more precisely the QoE for photo loading time in a particular usage of a photo album cloud service with regard to the influence of various parameters. Firstly, we validate a TCP throughput model and use it to calculate the photo loading time from a given photo size and network QoS. Thereafter, we formulate a mapping function to calculate the MOS value from a QoE model adding the output of the TCP model. From this mapping function, we can estimate QoE for photo loading time from a given photo size, its placement and network QoS. Our main contribution is to determine the trade-off between the size of photo and its placement to acquire a high QoE for photo loading time, which is important for the development of a photo album cloud service.

  @inproceedings{info3-inproceedings-2016-16, abstract = {The paradigm of Software as a Service has gained great achievements in the last decade. By transferring computation and storage to the cloud and migrating services to the edge network, users benefit from using demanding services on lightweight devices. However, the user perceived quality of experience (QoE) for these services is facing the challenges of network impairments and the accessibility of users. Unlike a typical PC-based software, the cloud provides users a location-aware, flexible placement of resource for a cost effective service. The geographical placement of content is therefore one of the key factors that affects the user's satisfaction. The closer the content to the user geographically is, the faster it will be delivered to the user that will also increase the user perceived QoE. In this work, we estimate more precisely the QoE for photo loading time in a particular usage of a photo album cloud service with regard to the influence of various parameters. Firstly, we validate a TCP throughput model and use it to calculate the photo loading time from a given photo size and network QoS. Thereafter, we formulate a mapping function to calculate the MOS value from a QoE model adding the output of the TCP model. From this mapping function, we can estimate QoE for photo loading time from a given photo size, its placement and network QoS. Our main contribution is to determine the trade-off between the size of photo and its placement to acquire a high QoE for photo loading time, which is important for the development of a photo album cloud service.}, address = {Ha Long, Vietnam}, author = {Dinh-Xuan, Lam and Seufert, Michael and Wamser, Florian and Tran-Gia, Phuoc}, booktitle = {IEEE 6th International Conference on Communications and Electronics (ICCE)}, keywords = {can}, month = {07}, title = {QoE Aware Placement of Content in Edge Networks on the Example of a Photo Album Cloud Service}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-16 %A Dinh-Xuan, Lam %A Seufert, Michael %A Wamser, Florian %A Tran-Gia, Phuoc %B IEEE 6th International Conference on Communications and Electronics (ICCE) %C Ha Long, Vietnam %D 2016 %T QoE Aware Placement of Content in Edge Networks on the Example of a Photo Album Cloud Service %X The paradigm of Software as a Service has gained great achievements in the last decade. By transferring computation and storage to the cloud and migrating services to the edge network, users benefit from using demanding services on lightweight devices. However, the user perceived quality of experience (QoE) for these services is facing the challenges of network impairments and the accessibility of users. Unlike a typical PC-based software, the cloud provides users a location-aware, flexible placement of resource for a cost effective service. The geographical placement of content is therefore one of the key factors that affects the user's satisfaction. The closer the content to the user geographically is, the faster it will be delivered to the user that will also increase the user perceived QoE. In this work, we estimate more precisely the QoE for photo loading time in a particular usage of a photo album cloud service with regard to the influence of various parameters. Firstly, we validate a TCP throughput model and use it to calculate the photo loading time from a given photo size and network QoS. Thereafter, we formulate a mapping function to calculate the MOS value from a QoE model adding the output of the TCP model. From this mapping function, we can estimate QoE for photo loading time from a given photo size, its placement and network QoS. Our main contribution is to determine the trade-off between the size of photo and its placement to acquire a high QoE for photo loading time, which is important for the development of a photo album cloud service.
• On Additive and Multiplicative QoS-QoE Models for Multiple QoS Parameters. Hoßfeld, Tobias; Skorin-Kapov, Lea; Heegaard, Poul E.; Varela, Martin; Chen, Kuan-Ta. In 5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS). 2016.
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  @inproceedings{info3-inproceedings-2016-23, author = {Hoßfeld, Tobias and Skorin-Kapov, Lea and Heegaard, Poul E. and Varela, Martin and Chen, Kuan-Ta}, booktitle = {5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS)}, keywords = {sys:hidden:inproceedings}, title = {On Additive and Multiplicative QoS-QoE Models for Multiple QoS Parameters}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-23 %A Hoßfeld, Tobias %A Skorin-Kapov, Lea %A Heegaard, Poul E. %A Varela, Martin %A Chen, Kuan-Ta %B 5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS) %D 2016 %T On Additive and Multiplicative QoS-QoE Models for Multiple QoS Parameters
• Sacrificing efficiency for quality of experience: YouTube’s redundant traffic behavior. Sieber, Christian; Heegaard, Poul E.; Hoßfeld, Tobias; Kellerer, Wolfgang. In IFIP Networking Conference. 2016.
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  @inproceedings{info3-inproceedings-2016-24, author = {Sieber, Christian and Heegaard, Poul E. and Hoßfeld, Tobias and Kellerer, Wolfgang}, booktitle = {IFIP Networking Conference}, keywords = {sys:hidden:inproceedings}, title = {Sacrificing efficiency for quality of experience: YouTube's redundant traffic behavior}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-24 %A Sieber, Christian %A Heegaard, Poul E. %A Hoßfeld, Tobias %A Kellerer, Wolfgang %B IFIP Networking Conference %D 2016 %T Sacrificing efficiency for quality of experience: YouTube's redundant traffic behavior
• QoE Management made uneasy: The case of Cloud Gaming. Sackl, Andreas; Schatz, Raimund; Hoßfeld, Tobias; Metzger, Florian; Lister, David; Irmer, Ralf. In IEEE Workshop on Quality of Experience-based Management for Future Internet Applications and Services (QoE-FI). 2016.
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  @inproceedings{info3-inproceedings-2016-26, author = {Sackl, Andreas and Schatz, Raimund and Hoßfeld, Tobias and Metzger, Florian and Lister, David and Irmer, Ralf}, booktitle = {IEEE Workshop on Quality of Experience-based Management for Future Internet Applications and Services (QoE-FI)}, keywords = {sys:hidden:inproceedings}, title = {QoE Management made uneasy: The case of Cloud Gaming}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-26 %A Sackl, Andreas %A Schatz, Raimund %A Hoßfeld, Tobias %A Metzger, Florian %A Lister, David %A Irmer, Ralf %B IEEE Workshop on Quality of Experience-based Management for Future Internet Applications and Services (QoE-FI) %D 2016 %T QoE Management made uneasy: The case of Cloud Gaming
• Enriching HTTP adaptive streaming with context awareness: A tunnel case study. Liotou, Eirini; Hoßfeld, Tobias; Moldovan, Christian; Metzger, Florian; Tsolkas, Dimitris; Passas, Nikos. In IEEE International Conference on Communications Workshops (ICC). 2016.
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  @inproceedings{info3-inproceedings-2016-25, author = {Liotou, Eirini and Hoßfeld, Tobias and Moldovan, Christian and Metzger, Florian and Tsolkas, Dimitris and Passas, Nikos}, booktitle = {IEEE International Conference on Communications Workshops (ICC)}, keywords = {sys:hidden:inproceedings}, title = {Enriching HTTP adaptive streaming with context awareness: A tunnel case study}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-25 %A Liotou, Eirini %A Hoßfeld, Tobias %A Moldovan, Christian %A Metzger, Florian %A Tsolkas, Dimitris %A Passas, Nikos %B IEEE International Conference on Communications Workshops (ICC) %D 2016 %T Enriching HTTP adaptive streaming with context awareness: A tunnel case study
• YouTube Can Do Better: Getting the Most Out of Video Adaptation. Moldovan, Christian; Sieber, Christian; Heegaard, Poul E.; Kellerer, Wolfgang; Hoßfeld, Tobias. In ITC and IEEE Workshop on QoE Centric Management (QCMan). 2016.
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  @inproceedings{info3-inproceedings-2016-28, author = {Moldovan, Christian and Sieber, Christian and Heegaard, Poul E. and Kellerer, Wolfgang and Hoßfeld, Tobias}, booktitle = {ITC and IEEE Workshop on QoE Centric Management (QCMan)}, keywords = {sys:hidden:inproceedings}, title = {YouTube Can Do Better: Getting the Most Out of Video Adaptation}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-28 %A Moldovan, Christian %A Sieber, Christian %A Heegaard, Poul E. %A Kellerer, Wolfgang %A Hoßfeld, Tobias %B ITC and IEEE Workshop on QoE Centric Management (QCMan) %D 2016 %T YouTube Can Do Better: Getting the Most Out of Video Adaptation
• Impact of Variances on the QoE in Video Streaming. Moldovan, Christian; Hoßfeld, Tobias. In ITC and IEEE Workshop on QoE Centric Management (QCMan). 2016.
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  @inproceedings{info3-inproceedings-2016-29, author = {Moldovan, Christian and Hoßfeld, Tobias}, booktitle = {ITC and IEEE Workshop on QoE Centric Management (QCMan)}, keywords = {sys:hidden:inproceedings}, title = {Impact of Variances on the QoE in Video Streaming}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-29 %A Moldovan, Christian %A Hoßfeld, Tobias %B ITC and IEEE Workshop on QoE Centric Management (QCMan) %D 2016 %T Impact of Variances on the QoE in Video Streaming
• Games and frames: A strange tale of QoE studies. Metzger, Florian; Rafetseder, Albert; Schwartz, Christian; Hoßfeld, Tobias. In Eighth International Conference on Quality of Multimedia Experience (QoMEX). 2016.
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  @inproceedings{info3-inproceedings-2016-27, author = {Metzger, Florian and Rafetseder, Albert and Schwartz, Christian and Hoßfeld, Tobias}, booktitle = {Eighth International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, title = {Games and frames: A strange tale of QoE studies}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-27 %A Metzger, Florian %A Rafetseder, Albert %A Schwartz, Christian %A Hoßfeld, Tobias %B Eighth International Conference on Quality of Multimedia Experience (QoMEX) %D 2016 %T Games and frames: A strange tale of QoE studies
• Application-Layer Monitoring of QoE Parameters for Mobile YouTube Video Streaming in the Field. Seufert, Michael; Casas, Pedro; Wamser, Florian; Wehner, Nikolas; Schatz, Raimund; Tran-Gia, Phuoc. In IEEE 6th International Conference on Communications and Electronics (ICCE). Ha Long, Vietnam, 2016.
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  YouTube video streaming is one of the most popular and most demanding services in cellular networks. Thus, operators are concerned about the quality of the streaming delivered by their networks and would like to monitor the Quality of Experience (QoE) of the end users. In this work, we conduct a field study of mobile YouTube video streaming, in which both network flow parameters and application-layer streaming parameters were monitored, and present the characteristics of current mobile YouTube streaming. The impact of both approaches is investigated showing that monitoring network parameters is not sufficient to directly infer the resulting QoE. In contrast, the streaming parameters, which can be obtained from application-layer monitoring, show high correlations to the subjectively experienced quality, and thus, are better suited for QoE monitoring.

  @inproceedings{info3-inproceedings-2016-9, abstract = {YouTube video streaming is one of the most popular and most demanding services in cellular networks. Thus, operators are concerned about the quality of the streaming delivered by their networks and would like to monitor the Quality of Experience (QoE) of the end users. In this work, we conduct a field study of mobile YouTube video streaming, in which both network flow parameters and application-layer streaming parameters were monitored, and present the characteristics of current mobile YouTube streaming. The impact of both approaches is investigated showing that monitoring network parameters is not sufficient to directly infer the resulting QoE. In contrast, the streaming parameters, which can be obtained from application-layer monitoring, show high correlations to the subjectively experienced quality, and thus, are better suited for QoE monitoring.}, address = {Ha Long, Vietnam}, author = {Seufert, Michael and Casas, Pedro and Wamser, Florian and Wehner, Nikolas and Schatz, Raimund and Tran-Gia, Phuoc}, booktitle = {IEEE 6th International Conference on Communications and Electronics (ICCE)}, keywords = {can}, month = {07}, title = {Application-Layer Monitoring of QoE Parameters for Mobile YouTube Video Streaming in the Field}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-9 %A Seufert, Michael %A Casas, Pedro %A Wamser, Florian %A Wehner, Nikolas %A Schatz, Raimund %A Tran-Gia, Phuoc %B IEEE 6th International Conference on Communications and Electronics (ICCE) %C Ha Long, Vietnam %D 2016 %T Application-Layer Monitoring of QoE Parameters for Mobile YouTube Video Streaming in the Field %X YouTube video streaming is one of the most popular and most demanding services in cellular networks. Thus, operators are concerned about the quality of the streaming delivered by their networks and would like to monitor the Quality of Experience (QoE) of the end users. In this work, we conduct a field study of mobile YouTube video streaming, in which both network flow parameters and application-layer streaming parameters were monitored, and present the characteristics of current mobile YouTube streaming. The impact of both approaches is investigated showing that monitoring network parameters is not sufficient to directly infer the resulting QoE. In contrast, the streaming parameters, which can be obtained from application-layer monitoring, show high correlations to the subjectively experienced quality, and thus, are better suited for QoE monitoring.
• Automated Decision Making Methods for the Multi-objective Optimization Task of Cloud Service Placement. Seufert, Michael; Lange, Stanislav; Meixner, Markus. In 1st International Workshop on Programmability for Cloud Networks and Applications (PROCON). Würzburg, Germany, 2016.
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  The network functions virtualization (NFV) paradigm provides advantages with respect to aspects like flexibility, costs, and scalability of networks. However, management and orchestration of the resulting networks also introduce new challenges. The placement of services and virtualized network functions (VNFs) is a multi-objective optimization task that confronts operators with a multitude of possible solutions that are incomparable among each other. The goal of this work is to investigate mechanisms that enable automated decision making between such multi dimensional solutions. To this end, we investigate techniques from the domain of multi attribute decision making that aggregate the performance of placements to a single numeric score. A comparison between resulting rankings of placements shows that many techniques produce similar results. Hence, placements that achieve good rankings according to many approaches might be viable candidates in the context of automated decision making.

  @inproceedings{info3-inproceedings-2016-12, abstract = {The network functions virtualization (NFV) paradigm provides advantages with respect to aspects like flexibility, costs, and scalability of networks. However, management and orchestration of the resulting networks also introduce new challenges. The placement of services and virtualized network functions (VNFs) is a multi-objective optimization task that confronts operators with a multitude of possible solutions that are incomparable among each other. The goal of this work is to investigate mechanisms that enable automated decision making between such multi dimensional solutions. To this end, we investigate techniques from the domain of multi attribute decision making that aggregate the performance of placements to a single numeric score. A comparison between resulting rankings of placements shows that many techniques produce similar results. Hence, placements that achieve good rankings according to many approaches might be viable candidates in the context of automated decision making.}, address = {Würzburg, Germany}, author = {Seufert, Michael and Lange, Stanislav and Meixner, Markus}, booktitle = {1st International Workshop on Programmability for Cloud Networks and Applications (PROCON)}, keywords = {can}, month = {09}, title = {Automated Decision Making Methods for the Multi-objective Optimization Task of Cloud Service Placement}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-12 %A Seufert, Michael %A Lange, Stanislav %A Meixner, Markus %B 1st International Workshop on Programmability for Cloud Networks and Applications (PROCON) %C Würzburg, Germany %D 2016 %T Automated Decision Making Methods for the Multi-objective Optimization Task of Cloud Service Placement %X The network functions virtualization (NFV) paradigm provides advantages with respect to aspects like flexibility, costs, and scalability of networks. However, management and orchestration of the resulting networks also introduce new challenges. The placement of services and virtualized network functions (VNFs) is a multi-objective optimization task that confronts operators with a multitude of possible solutions that are incomparable among each other. The goal of this work is to investigate mechanisms that enable automated decision making between such multi dimensional solutions. To this end, we investigate techniques from the domain of multi attribute decision making that aggregate the performance of placements to a single numeric score. A comparison between resulting rankings of placements shows that many techniques produce similar results. Hence, placements that achieve good rankings according to many approaches might be viable candidates in the context of automated decision making.
• A Comprehensive End-to-End Lag Model for Online and Cloud Video Gaming. Metzger, Florian; Rafetseder, Albert; Schwartz, Christian. In Proc. 5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS 2016). 2016.
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  To further the knowledge of basic game mechanics and improve future video game Quality of Experience (QoE) studies we present a model and simulation for End-to-End (E2E) lag in networked and cloud computer games. E2E lag describes the latency between a user's action and the display of the action's results on the screen, thus providing both a basic measure for interactivity and a fundamental parameter to derived QoE metrics. In contrast to E2E lag models that focus on the network Round-Trip Time (RTT), the presented work also factors in the game's tickrate and framerate (and codec latencies in the case of cloud games). This reveals side effects that can entirely mask the network delay's contribution to the total lag, an important notion to consider for future game studies.

  @inproceedings{info3-inproceedings-2016-31, abstract = {To further the knowledge of basic game mechanics and improve future video game Quality of Experience (QoE) studies we present a model and simulation for End-to-End (E2E) lag in networked and cloud computer games. E2E lag describes the latency between a user's action and the display of the action's results on the screen, thus providing both a basic measure for interactivity and a fundamental parameter to derived QoE metrics. In contrast to E2E lag models that focus on the network Round-Trip Time (RTT), the presented work also factors in the game's tickrate and framerate (and codec latencies in the case of cloud games). This reveals side effects that can entirely mask the network delay's contribution to the total lag, an important notion to consider for future game studies.}, author = {Metzger, Florian and Rafetseder, Albert and Schwartz, Christian}, booktitle = {Proc. 5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS 2016)}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {A Comprehensive End-to-End Lag Model for Online and Cloud Video Gaming}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-31 %A Metzger, Florian %A Rafetseder, Albert %A Schwartz, Christian %B Proc. 5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS 2016) %D 2016 %T A Comprehensive End-to-End Lag Model for Online and Cloud Video Gaming %X To further the knowledge of basic game mechanics and improve future video game Quality of Experience (QoE) studies we present a model and simulation for End-to-End (E2E) lag in networked and cloud computer games. E2E lag describes the latency between a user's action and the display of the action's results on the screen, thus providing both a basic measure for interactivity and a fundamental parameter to derived QoE metrics. In contrast to E2E lag models that focus on the network Round-Trip Time (RTT), the presented work also factors in the game's tickrate and framerate (and codec latencies in the case of cloud games). This reveals side effects that can entirely mask the network delay's contribution to the total lag, an important notion to consider for future game studies.
• Performance Analysis of Hierarchical Caching Systems with Bandwidth Constraints. Burger, Valentin; Zinner, Thomas. In Proceedings of the International Telecommunication Networks and Applications Conference. Dunedin, New Zealand, 2016.
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  The vast majority of Internet traffic is carried by content delivery networks. A high potential to bring content even closer to consumers and to reduce energy cost is achieved by the nano data center (NaDa) concept that has been proposed in recent work. In this approach the capacity available on small devices such as home gateways is used to support content delivery in an hierarchical caching system. In this work, we present a method to determine the efficiency of hierarchical content delivery networks with limited bandwidth, such as in the NaDa approach, analytically. We analyze the Internet Census Dataset to assess the number of available devices on autonomous system level. We evaluate the potential of hierarchical cache networks with bandwidth constraints to assist content delivery and determine its limits.

  @inproceedings{info3-inproceedings-2016-22, abstract = {The vast majority of Internet traffic is carried by content delivery networks. A high potential to bring content even closer to consumers and to reduce energy cost is achieved by the nano data center (NaDa) concept that has been proposed in recent work. In this approach the capacity available on small devices such as home gateways is used to support content delivery in an hierarchical caching system. In this work, we present a method to determine the efficiency of hierarchical content delivery networks with limited bandwidth, such as in the NaDa approach, analytically. We analyze the Internet Census Dataset to assess the number of available devices on autonomous system level. We evaluate the potential of hierarchical cache networks with bandwidth constraints to assist content delivery and determine its limits.}, address = {Dunedin, New Zealand}, author = {Burger, Valentin and Zinner, Thomas}, booktitle = {Proceedings of the International Telecommunication Networks and Applications Conference}, keywords = {can}, month = 12, title = {Performance Analysis of Hierarchical Caching Systems with Bandwidth Constraints}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-22 %A Burger, Valentin %A Zinner, Thomas %B Proceedings of the International Telecommunication Networks and Applications Conference %C Dunedin, New Zealand %D 2016 %T Performance Analysis of Hierarchical Caching Systems with Bandwidth Constraints %X The vast majority of Internet traffic is carried by content delivery networks. A high potential to bring content even closer to consumers and to reduce energy cost is achieved by the nano data center (NaDa) concept that has been proposed in recent work. In this approach the capacity available on small devices such as home gateways is used to support content delivery in an hierarchical caching system. In this work, we present a method to determine the efficiency of hierarchical content delivery networks with limited bandwidth, such as in the NaDa approach, analytically. We analyze the Internet Census Dataset to assess the number of available devices on autonomous system level. We evaluate the potential of hierarchical cache networks with bandwidth constraints to assist content delivery and determine its limits.
• Evaluating the Impact of WiFi Offloading on Mobile Users of HTTP Adaptive Video Streaming. Seufert, Michael; Burger, Valentin; Kaup, Fabian. In 5th IEEE International Workshop on Quality of Experience for Multimedia Communications (QoEMC). Washington, DC, USA, 2016.
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  In a recent trend to lessen the load on cellular networks in cities, users are offered to offload mobile connections to lower cost WiFi networks. In this work, we conduct a simulative performance evaluation of the impact of WiFi offloading for a mobile end user of a HTTP adaptive video streaming (HAS) service depending on availability and range of the WiFi hotspots. The simulation is based on connectivity measurements from a German city and evaluates the key performance indicators for the QoE of HAS, i.e., initial delay, stalling, and quality adaptation. Additionally, a smartphone energy model is applied to assess the energy consumption during the streaming. The results indicate that WiFi offloading of HAS connections to public WiFi hotspots is not attractive for end users both in terms of QoE and energy consumption. However, it can be shown that WiFi offloading can be beneficial also for end users in case high bandwidths can be received via WiFi.

  @inproceedings{info3-inproceedings-2016-18, abstract = {In a recent trend to lessen the load on cellular networks in cities, users are offered to offload mobile connections to lower cost WiFi networks. In this work, we conduct a simulative performance evaluation of the impact of WiFi offloading for a mobile end user of a HTTP adaptive video streaming (HAS) service depending on availability and range of the WiFi hotspots. The simulation is based on connectivity measurements from a German city and evaluates the key performance indicators for the QoE of HAS, i.e., initial delay, stalling, and quality adaptation. Additionally, a smartphone energy model is applied to assess the energy consumption during the streaming. The results indicate that WiFi offloading of HAS connections to public WiFi hotspots is not attractive for end users both in terms of QoE and energy consumption. However, it can be shown that WiFi offloading can be beneficial also for end users in case high bandwidths can be received via WiFi.}, address = {Washington, DC, USA}, author = {Seufert, Michael and Burger, Valentin and Kaup, Fabian}, booktitle = {5th IEEE International Workshop on Quality of Experience for Multimedia Communications (QoEMC)}, keywords = {can}, month = 12, title = {Evaluating the Impact of WiFi Offloading on Mobile Users of HTTP Adaptive Video Streaming}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-18 %A Seufert, Michael %A Burger, Valentin %A Kaup, Fabian %B 5th IEEE International Workshop on Quality of Experience for Multimedia Communications (QoEMC) %C Washington, DC, USA %D 2016 %T Evaluating the Impact of WiFi Offloading on Mobile Users of HTTP Adaptive Video Streaming %X In a recent trend to lessen the load on cellular networks in cities, users are offered to offload mobile connections to lower cost WiFi networks. In this work, we conduct a simulative performance evaluation of the impact of WiFi offloading for a mobile end user of a HTTP adaptive video streaming (HAS) service depending on availability and range of the WiFi hotspots. The simulation is based on connectivity measurements from a German city and evaluates the key performance indicators for the QoE of HAS, i.e., initial delay, stalling, and quality adaptation. Additionally, a smartphone energy model is applied to assess the energy consumption during the streaming. The results indicate that WiFi offloading of HAS connections to public WiFi hotspots is not attractive for end users both in terms of QoE and energy consumption. However, it can be shown that WiFi offloading can be beneficial also for end users in case high bandwidths can be received via WiFi.
• Simulation Framework for Distributed SDN-Controller Architectures in OMNeT++. Gray, Nicholas; Zinner, Thomas; Gebert, Steffen; Tran-Gia, Phuoc. In 8th EAI International Conference on Mobile Networks and Management (MONAMI 2016). Abu Dhabi, United Arab Emirates, 2016.
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  SDN introduces the seperation of network control and network data plane. The control plane is removed from distributed network entities and logically centralized as the SDN controller. To provide resilience and performance such a logically centralized controller may again be physically distributed. Scenarios featuring distributed controller architectures include data center deployments, where controller instances synchronize states on small distances and delays, or continental WAN deployments with long distances and delays between controllers. The contribution of this paper is an OMNET++ based simulation framework for assessing the performance of distributed SDN controller architectures. Relevant protocols and controller applications are modelled with a high level of detail. Further, an exemplary implementation of two different controller architectures, namely Hyperflow and Kandoo, is included. Initial results based on the provided implementations are presented.

  @inproceedings{info3-inproceedings-2016-20, abstract = {SDN introduces the seperation of network control and network data plane. The control plane is removed from distributed network entities and logically centralized as the SDN controller. To provide resilience and performance such a logically centralized controller may again be physically distributed. Scenarios featuring distributed controller architectures include data center deployments, where controller instances synchronize states on small distances and delays, or continental WAN deployments with long distances and delays between controllers. The contribution of this paper is an OMNET++ based simulation framework for assessing the performance of distributed SDN controller architectures. Relevant protocols and controller applications are modelled with a high level of detail. Further, an exemplary implementation of two different controller architectures, namely Hyperflow and Kandoo, is included. Initial results based on the provided implementations are presented.}, address = {Abu Dhabi, United Arab Emirates}, author = {Gray, Nicholas and Zinner, Thomas and Gebert, Steffen and Tran-Gia, Phuoc}, booktitle = {8th EAI International Conference on Mobile Networks and Management (MONAMI 2016)}, keywords = {sendate}, month = 10, title = {Simulation Framework for Distributed SDN-Controller Architectures in OMNeT++}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-20 %A Gray, Nicholas %A Zinner, Thomas %A Gebert, Steffen %A Tran-Gia, Phuoc %B 8th EAI International Conference on Mobile Networks and Management (MONAMI 2016) %C Abu Dhabi, United Arab Emirates %D 2016 %T Simulation Framework for Distributed SDN-Controller Architectures in OMNeT++ %X SDN introduces the seperation of network control and network data plane. The control plane is removed from distributed network entities and logically centralized as the SDN controller. To provide resilience and performance such a logically centralized controller may again be physically distributed. Scenarios featuring distributed controller architectures include data center deployments, where controller instances synchronize states on small distances and delays, or continental WAN deployments with long distances and delays between controllers. The contribution of this paper is an OMNET++ based simulation framework for assessing the performance of distributed SDN controller architectures. Relevant protocols and controller applications are modelled with a high level of detail. Further, an exemplary implementation of two different controller architectures, namely Hyperflow and Kandoo, is included. Initial results based on the provided implementations are presented.
• Processing Time Comparison of a Hardware-Based Firewall and its Virtualized Counterpart. Gebert, Steffen; Müssig, Alexander; Lange, Stanislav; Zinner, Thomas; Gray, Nicholas; Tran-Gia, Phuoc. In 8th EAI International Conference on Mobile Networks and Management (MONAMI 2016). Abu Dhabi, United Arab Emirates, 2016.
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  @inproceedings{info3-inproceedings-2016-19, address = {Abu Dhabi, United Arab Emirates}, author = {Gebert, Steffen and Müssig, Alexander and Lange, Stanislav and Zinner, Thomas and Gray, Nicholas and Tran-Gia, Phuoc}, booktitle = {8th EAI International Conference on Mobile Networks and Management (MONAMI 2016)}, keywords = {sardine}, month = 10, title = {Processing Time Comparison of a Hardware-Based Firewall and its Virtualized Counterpart}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-19 %A Gebert, Steffen %A Müssig, Alexander %A Lange, Stanislav %A Zinner, Thomas %A Gray, Nicholas %A Tran-Gia, Phuoc %B 8th EAI International Conference on Mobile Networks and Management (MONAMI 2016) %C Abu Dhabi, United Arab Emirates %D 2016 %T Processing Time Comparison of a Hardware-Based Firewall and its Virtualized Counterpart
• Concept for Client-initiated Selection of Cloud Instances for Improving QoE of Distributed Cloud Services. Wamser, Florian; Seufert, Michael; Höfner, Steffen; Tran-Gia, Phuoc. In ACM SIGCOMM Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE). Florianópolis, Brazil, 2016.
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  We introduce a concept for client-initiated selection of service location and service quality for improving the Quality of Experience (QoE) of general cloud services. It is loosely based on the HTTP adaptive streaming approach (e.g., MPEG DASH). A manifest file compiled by the cloud service provider specifies the available service locations and qualities, from which the user selects the optimal service instance based on contextual information obtained from client measurements and user preferences. The proposed concept is defined and is implemented in two client-based decision algorithms for improving the QoE of a simple picture gallery cloud service. These decision algorithms are evaluated and their impact on the service delivery is discussed. The evaluation shows that it is possible to improve the service location and quality selection by light-weight client-based algorithms.

  @inproceedings{info3-inproceedings-2016-14, abstract = {We introduce a concept for client-initiated selection of service location and service quality for improving the Quality of Experience (QoE) of general cloud services. It is loosely based on the HTTP adaptive streaming approach (e.g., MPEG DASH). A manifest file compiled by the cloud service provider specifies the available service locations and qualities, from which the user selects the optimal service instance based on contextual information obtained from client measurements and user preferences. The proposed concept is defined and is implemented in two client-based decision algorithms for improving the QoE of a simple picture gallery cloud service. These decision algorithms are evaluated and their impact on the service delivery is discussed. The evaluation shows that it is possible to improve the service location and quality selection by light-weight client-based algorithms.}, address = {Florianópolis, Brazil}, author = {Wamser, Florian and Seufert, Michael and Höfner, Steffen and Tran-Gia, Phuoc}, booktitle = {ACM SIGCOMM Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE)}, keywords = {can}, month = {08}, title = {Concept for Client-initiated Selection of Cloud Instances for Improving QoE of Distributed Cloud Services}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-14 %A Wamser, Florian %A Seufert, Michael %A Höfner, Steffen %A Tran-Gia, Phuoc %B ACM SIGCOMM Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE) %C Florianópolis, Brazil %D 2016 %T Concept for Client-initiated Selection of Cloud Instances for Improving QoE of Distributed Cloud Services %X We introduce a concept for client-initiated selection of service location and service quality for improving the Quality of Experience (QoE) of general cloud services. It is loosely based on the HTTP adaptive streaming approach (e.g., MPEG DASH). A manifest file compiled by the cloud service provider specifies the available service locations and qualities, from which the user selects the optimal service instance based on contextual information obtained from client measurements and user preferences. The proposed concept is defined and is implemented in two client-based decision algorithms for improving the QoE of a simple picture gallery cloud service. These decision algorithms are evaluated and their impact on the service delivery is discussed. The evaluation shows that it is possible to improve the service location and quality selection by light-weight client-based algorithms.
• ZOOM: Lightweight SDN-based Elephant Detection. Gebert, Steffen; Geissler, Stefan; Zinner, Thomas; Nguyen-Ngoc, Anh; Lange, Stanislav; Tran-Gia, Phuoc. In First International Workshop on Programmability for Cloud Networks and Applications (PROCON). Würzburg, Germany, 2016.
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  Software Defined Networking (SDN) offers a holistic view of the network through a centralized control plane. Consequently, routing decisions can be made based on global knowledge about the network topology as well as its current state. As long living flows are suitable candidates for rerouting, their detection is crucial for efficient flow based traffic management. This work proposes the ZOOM algorithm for elephant detection in SDN networks. To this end, ZOOM follows a very lightweight approach that only uses packet counters implemented by OpenFlow switches and thus does not require any additional hardware. By exploiting this feature of OpenFlow switches, ZOOM allows lightweight and cost-effective elephant detection.

  @inproceedings{info3-inproceedings-2016-8, abstract = {Software Defined Networking (SDN) offers a holistic view of the network through a centralized control plane. Consequently, routing decisions can be made based on global knowledge about the network topology as well as its current state. As long living flows are suitable candidates for rerouting, their detection is crucial for efficient flow based traffic management. This work proposes the ZOOM algorithm for elephant detection in SDN networks. To this end, ZOOM follows a very lightweight approach that only uses packet counters implemented by OpenFlow switches and thus does not require any additional hardware. By exploiting this feature of OpenFlow switches, ZOOM allows lightweight and cost-effective elephant detection.}, address = {Würzburg, Germany}, author = {Gebert, Steffen and Geissler, Stefan and Zinner, Thomas and Nguyen-Ngoc, Anh and Lange, Stanislav and Tran-Gia, Phuoc}, booktitle = {First International Workshop on Programmability for Cloud Networks and Applications (PROCON)}, keywords = {sardine}, month = {09}, title = {ZOOM: Lightweight SDN-based Elephant Detection}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-8 %A Gebert, Steffen %A Geissler, Stefan %A Zinner, Thomas %A Nguyen-Ngoc, Anh %A Lange, Stanislav %A Tran-Gia, Phuoc %B First International Workshop on Programmability for Cloud Networks and Applications (PROCON) %C Würzburg, Germany %D 2016 %T ZOOM: Lightweight SDN-based Elephant Detection %X Software Defined Networking (SDN) offers a holistic view of the network through a centralized control plane. Consequently, routing decisions can be made based on global knowledge about the network topology as well as its current state. As long living flows are suitable candidates for rerouting, their detection is crucial for efficient flow based traffic management. This work proposes the ZOOM algorithm for elephant detection in SDN networks. To this end, ZOOM follows a very lightweight approach that only uses packet counters implemented by OpenFlow switches and thus does not require any additional hardware. By exploiting this feature of OpenFlow switches, ZOOM allows lightweight and cost-effective elephant detection.
• Analytic Model for SDN Controller Traffic and Switch Table Occupancy. Metter, Christopher; Seufert, Michael; Wamser, Florian; Zinner, Thomas; Tran-Gia, Phuoc. In 12th International Conference on Network and Service Management (CNSM). Best Paper Award, Montreal, Canada, 2016.
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  Software Defined Networking (SDN) is a major paradigm in the field of current communication networks. SDN is used as the basis of many new networks although few performance models are available in the literature, and the majority of performance evaluations are based primarily on practical measurements. To fill this gap, we develop an analytical model to assess SDN control plane traffic as well as the occupancy of the flow table of an SDN switch. The contribution of this work is the formulation of the model for the performance-decisive parameters control-plane traffic and flow table occupancy and the application of the model for different data plane traffic characteristics. In the end, there is a discussion about the setting of time-out values for storing flow entries in the switch flow table depending on the traffic characteristics in the data plane. The trade-off between the signaling traffic in the control plane and the occupancy of the flow table is discussed in order to minimize both.

  @inproceedings{info3-inproceedings-2016-17, abstract = {Software Defined Networking (SDN) is a major paradigm in the field of current communication networks. SDN is used as the basis of many new networks although few performance models are available in the literature, and the majority of performance evaluations are based primarily on practical measurements. To fill this gap, we develop an analytical model to assess SDN control plane traffic as well as the occupancy of the flow table of an SDN switch. The contribution of this work is the formulation of the model for the performance-decisive parameters control-plane traffic and flow table occupancy and the application of the model for different data plane traffic characteristics. In the end, there is a discussion about the setting of time-out values for storing flow entries in the switch flow table depending on the traffic characteristics in the data plane. The trade-off between the signaling traffic in the control plane and the occupancy of the flow table is discussed in order to minimize both.}, address = {Best Paper Award, Montreal, Canada}, author = {Metter, Christopher and Seufert, Michael and Wamser, Florian and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {12th International Conference on Network and Service Management (CNSM)}, keywords = {can}, month = 10, title = {Analytic Model for SDN Controller Traffic and Switch Table Occupancy}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-17 %A Metter, Christopher %A Seufert, Michael %A Wamser, Florian %A Zinner, Thomas %A Tran-Gia, Phuoc %B 12th International Conference on Network and Service Management (CNSM) %C Best Paper Award, Montreal, Canada %D 2016 %T Analytic Model for SDN Controller Traffic and Switch Table Occupancy %X Software Defined Networking (SDN) is a major paradigm in the field of current communication networks. SDN is used as the basis of many new networks although few performance models are available in the literature, and the majority of performance evaluations are based primarily on practical measurements. To fill this gap, we develop an analytical model to assess SDN control plane traffic as well as the occupancy of the flow table of an SDN switch. The contribution of this work is the formulation of the model for the performance-decisive parameters control-plane traffic and flow table occupancy and the application of the model for different data plane traffic characteristics. In the end, there is a discussion about the setting of time-out values for storing flow entries in the switch flow table depending on the traffic characteristics in the data plane. The trade-off between the signaling traffic in the control plane and the occupancy of the flow table is discussed in order to minimize both.
• Towards a Framework for Comparing QoE-Centric Mechanisms of Application-Network Interaction. Schwarzmann, Susanna; Zinner, Thomas; Dobrijevic, Ognjen. In Proceedings of the 4th International IEEE Workshop on Quality of Experience Centric Management (2016). Würzburg, 2016.
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  @inproceedings{info3-inproceedings-2015-26, address = {Würzburg}, author = {Schwarzmann, Susanna and Zinner, Thomas and Dobrijevic, Ognjen}, booktitle = {Proceedings of the 4th International IEEE Workshop on Quality of Experience Centric Management (2016)}, keywords = {dfg-sdn}, month = {09}, title = {Towards a Framework for Comparing QoE-Centric Mechanisms of Application-Network Interaction}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2015-26 %A Schwarzmann, Susanna %A Zinner, Thomas %A Dobrijevic, Ognjen %B Proceedings of the 4th International IEEE Workshop on Quality of Experience Centric Management (2016) %C Würzburg %D 2016 %T Towards a Framework for Comparing QoE-Centric Mechanisms of Application-Network Interaction
• Correlating QoE and Technical Parameters of an SAP System in an Enterprise Environment. Borchert, Kathrin; Hirth, Matthias; Zinner, Thomas; Mocanu, Decebal Constantin. In QCMan IEEE Workshop on QoE centric Management. 2016.
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  @inproceedings{info3-inproceedings-2016-15, author = {Borchert, Kathrin and Hirth, Matthias and Zinner, Thomas and Mocanu, Decebal Constantin}, booktitle = {QCMan IEEE Workshop on QoE centric Management}, keywords = {oekonet}, month = {09}, title = {Correlating QoE and Technical Parameters of an SAP System in an Enterprise Environment}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-15 %A Borchert, Kathrin %A Hirth, Matthias %A Zinner, Thomas %A Mocanu, Decebal Constantin %B QCMan IEEE Workshop on QoE centric Management %D 2016 %T Correlating QoE and Technical Parameters of an SAP System in an Enterprise Environment
• Bridging the Gap between QoE and User Engagement in HTTP Video Streaming. Moldovan, Christian; Metzger, Florian. In 28th International Teletraffic Congress (ITC 28). 2016.
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  On video streaming platforms, users expect a high Quality of Experience (QoE). In contrast, service and content providers aim at high User Engagement, most notably because their revenue is usually dependent on it. In order to satisfy users, it is critical to know how QoE is related to the User Engagement. However, no model for this relation exists yet. Current approaches to managing QoE are usually based on traffic analysis. However, this will become more difficult in the future since the encryption of Internet traffic progresses. In this paper, we present an approach to bringing QoE and User Engagement together with video streaming as the use case. We do this by fitting existing measurement data of User Engagement to obtain a model. Furthermore, we extend the existing queuing model for QoE and investigate the correlation between QoE and User Engagement in a simulation. Hereby, we model different scenarios where we quantify network bandwidth and video requirements. Our results show that there is a strong correlation between QoE and User Engagement. Additionally, we observe that simple buffer policies, which do not rely on buffer information, can still perform well. These revelations open the way for new approaches to QoE Management in the future Internet.

  @inproceedings{info3-inproceedings-2016-30, abstract = {On video streaming platforms, users expect a high Quality of Experience (QoE). In contrast, service and content providers aim at high User Engagement, most notably because their revenue is usually dependent on it. In order to satisfy users, it is critical to know how QoE is related to the User Engagement. However, no model for this relation exists yet. Current approaches to managing QoE are usually based on traffic analysis. However, this will become more difficult in the future since the encryption of Internet traffic progresses. In this paper, we present an approach to bringing QoE and User Engagement together with video streaming as the use case. We do this by fitting existing measurement data of User Engagement to obtain a model. Furthermore, we extend the existing queuing model for QoE and investigate the correlation between QoE and User Engagement in a simulation. Hereby, we model different scenarios where we quantify network bandwidth and video requirements. Our results show that there is a strong correlation between QoE and User Engagement. Additionally, we observe that simple buffer policies, which do not rely on buffer information, can still perform well. These revelations open the way for new approaches to QoE Management in the future Internet.}, author = {Moldovan, Christian and Metzger, Florian}, booktitle = {28th International Teletraffic Congress (ITC 28)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Bridging the Gap between QoE and User Engagement in HTTP Video Streaming}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-30 %A Moldovan, Christian %A Metzger, Florian %B 28th International Teletraffic Congress (ITC 28) %D 2016 %T Bridging the Gap between QoE and User Engagement in HTTP Video Streaming %X On video streaming platforms, users expect a high Quality of Experience (QoE). In contrast, service and content providers aim at high User Engagement, most notably because their revenue is usually dependent on it. In order to satisfy users, it is critical to know how QoE is related to the User Engagement. However, no model for this relation exists yet. Current approaches to managing QoE are usually based on traffic analysis. However, this will become more difficult in the future since the encryption of Internet traffic progresses. In this paper, we present an approach to bringing QoE and User Engagement together with video streaming as the use case. We do this by fitting existing measurement data of User Engagement to obtain a model. Furthermore, we extend the existing queuing model for QoE and investigate the correlation between QoE and User Engagement in a simulation. Hereby, we model different scenarios where we quantify network bandwidth and video requirements. Our results show that there is a strong correlation between QoE and User Engagement. Additionally, we observe that simple buffer policies, which do not rely on buffer information, can still perform well. These revelations open the way for new approaches to QoE Management in the future Internet.
• Performance Modeling of Softwarized Network Functions Using Discrete-Time Analysis. Gebert, Steffen; Zinner, Thomas; Lange, Stanislav; Schwartz, Christian; Tran-Gia, Phuoc. In 28th International Teletraffic Congress (ITC). Würzburg, Germany, 2016.
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  The softwarization of networks promises cost savings and better scalability of network functions by moving functionality from specialized devices into commercial off-the-shelf hardware. Generalized computing hardware offers many degrees for adjustment and tuning, which can affect performance and resource utilization. One of these adjustments are the interrupt mitigation techniques implemented by modern network interface cards and operating systems. Using these, an administrator can optimize either lower latencies or lower CPU overhead for processing of network traffic. In this work, an analytical model that allows computing relevant performance metrics like the packet processing time and the packet loss for generic virtualized network functions running on commodity hardware is developed. The applicability of the model is shown by comparing its outcome with measurements conducted in a local testbed. Based on this model, impact factors like the average packet interarrival time, the interarrival time distribution, and the duration of the interrupt aggregation interval are studied.

  @inproceedings{info3-inproceedings-2016-4, abstract = {The softwarization of networks promises cost savings and better scalability of network functions by moving functionality from specialized devices into commercial off-the-shelf hardware. Generalized computing hardware offers many degrees for adjustment and tuning, which can affect performance and resource utilization. One of these adjustments are the interrupt mitigation techniques implemented by modern network interface cards and operating systems. Using these, an administrator can optimize either lower latencies or lower CPU overhead for processing of network traffic. In this work, an analytical model that allows computing relevant performance metrics like the packet processing time and the packet loss for generic virtualized network functions running on commodity hardware is developed. The applicability of the model is shown by comparing its outcome with measurements conducted in a local testbed. Based on this model, impact factors like the average packet interarrival time, the interarrival time distribution, and the duration of the interrupt aggregation interval are studied.}, address = {Würzburg, Germany}, author = {Gebert, Steffen and Zinner, Thomas and Lange, Stanislav and Schwartz, Christian and Tran-Gia, Phuoc}, booktitle = {28th International Teletraffic Congress (ITC)}, keywords = {sendate}, month = {09}, title = {Performance Modeling of Softwarized Network Functions Using Discrete-Time Analysis}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-4 %A Gebert, Steffen %A Zinner, Thomas %A Lange, Stanislav %A Schwartz, Christian %A Tran-Gia, Phuoc %B 28th International Teletraffic Congress (ITC) %C Würzburg, Germany %D 2016 %T Performance Modeling of Softwarized Network Functions Using Discrete-Time Analysis %X The softwarization of networks promises cost savings and better scalability of network functions by moving functionality from specialized devices into commercial off-the-shelf hardware. Generalized computing hardware offers many degrees for adjustment and tuning, which can affect performance and resource utilization. One of these adjustments are the interrupt mitigation techniques implemented by modern network interface cards and operating systems. Using these, an administrator can optimize either lower latencies or lower CPU overhead for processing of network traffic. In this work, an analytical model that allows computing relevant performance metrics like the packet processing time and the packet loss for generic virtualized network functions running on commodity hardware is developed. The applicability of the model is shown by comparing its outcome with measurements conducted in a local testbed. Based on this model, impact factors like the average packet interarrival time, the interarrival time distribution, and the duration of the interrupt aggregation interval are studied.
• Principles of Information Neutrality and Counter Measures Against Biased Information. Burger, Valentin; Hirth, Matthias; Hoßfeld, Tobias; Tran-Gia, Phuoc. In Lecture Notes in Informatics: Value-Sensitive Design of Internet-Based Services. Klagenfurt, Austria, 2016.
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  The Internet serves as ubiquitous, prompt source of information in our society. Due to the giant amount of information, the access to the information relies on information processing mechanisms as implemented in search engines, product recommendation systems, or online social networks. As a result of the engineered preprocessing mechanism, the retrieved information is biased and does not represent a neutral view on the available information, while end-users often are not aware of this bias. In this article, we define the term “Information Neutrality”, review current principles of information processing in the Internet and discuss influence factors hindering Information Neutrality as well as appropriate countermeasures. The main contribution of this article is to raise the awareness of Information Neutrality as an emerging key challenge in the Internet and to potentially consider Information Neutrality as a factor in the value-sensitive design of Internet-based services.

  @inproceedings{info3-inproceedings-2016-21, abstract = {The Internet serves as ubiquitous, prompt source of information in our society. Due to the giant amount of information, the access to the information relies on information processing mechanisms as implemented in search engines, product recommendation systems, or online social networks. As a result of the engineered preprocessing mechanism, the retrieved information is biased and does not represent a neutral view on the available information, while end-users often are not aware of this bias. In this article, we define the term “Information Neutrality”, review current principles of information processing in the Internet and discuss influence factors hindering Information Neutrality as well as appropriate countermeasures. The main contribution of this article is to raise the awareness of Information Neutrality as an emerging key challenge in the Internet and to potentially consider Information Neutrality as a factor in the value-sensitive design of Internet-based services.}, address = {Klagenfurt, Austria}, author = {Burger, Valentin and Hirth, Matthias and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {Lecture Notes in Informatics: Value-Sensitive Design of Internet-Based Services}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Principles of Information Neutrality and Counter Measures Against Biased Information}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-21 %A Burger, Valentin %A Hirth, Matthias %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B Lecture Notes in Informatics: Value-Sensitive Design of Internet-Based Services %C Klagenfurt, Austria %D 2016 %T Principles of Information Neutrality and Counter Measures Against Biased Information %X The Internet serves as ubiquitous, prompt source of information in our society. Due to the giant amount of information, the access to the information relies on information processing mechanisms as implemented in search engines, product recommendation systems, or online social networks. As a result of the engineered preprocessing mechanism, the retrieved information is biased and does not represent a neutral view on the available information, while end-users often are not aware of this bias. In this article, we define the term “Information Neutrality”, review current principles of information processing in the Internet and discuss influence factors hindering Information Neutrality as well as appropriate countermeasures. The main contribution of this article is to raise the awareness of Information Neutrality as an emerging key challenge in the Internet and to potentially consider Information Neutrality as a factor in the value-sensitive design of Internet-based services.
• Assessing the Accuracy of Network Estimations in the DOTA 2 Game Client. Hirth, Matthias; Allendorf, Fabian; Metzger, Florian; Schwartz, Christian. In Workshop on Perceptual Quality of Systems (PQS). Berlin, Germany, 2016.
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  Online video games and the subjective quality of player inter- actions with them rely on good network conditions. Almost equally important is a good and timely knowledge of such conditions in order to take proper countermeasures to worsening conditions. To this end, many online video games include components for estimating the current network status. In this paper, we examine the accuracy of those estimations for the popular competitive multiplayer game DOTA 2. Our results show that the game client is capable of performing a good estimation of the delay and packet loss, but only after a rather large initial delay.

  @inproceedings{info3-inproceedings-2016-13, abstract = {Online video games and the subjective quality of player inter- actions with them rely on good network conditions. Almost equally important is a good and timely knowledge of such conditions in order to take proper countermeasures to worsening conditions. To this end, many online video games include components for estimating the current network status. In this paper, we examine the accuracy of those estimations for the popular competitive multiplayer game DOTA 2. Our results show that the game client is capable of performing a good estimation of the delay and packet loss, but only after a rather large initial delay.}, address = {Berlin, Germany}, author = {Hirth, Matthias and Allendorf, Fabian and Metzger, Florian and Schwartz, Christian}, booktitle = {Workshop on Perceptual Quality of Systems (PQS)}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Assessing the Accuracy of Network Estimations in the DOTA 2 Game Client}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-13 %A Hirth, Matthias %A Allendorf, Fabian %A Metzger, Florian %A Schwartz, Christian %B Workshop on Perceptual Quality of Systems (PQS) %C Berlin, Germany %D 2016 %T Assessing the Accuracy of Network Estimations in the DOTA 2 Game Client %X Online video games and the subjective quality of player inter- actions with them rely on good network conditions. Almost equally important is a good and timely knowledge of such conditions in order to take proper countermeasures to worsening conditions. To this end, many online video games include components for estimating the current network status. In this paper, we examine the accuracy of those estimations for the popular competitive multiplayer game DOTA 2. Our results show that the game client is capable of performing a good estimation of the delay and packet loss, but only after a rather large initial delay.
• One Shot Crowdtesting: Approaching the Extremes of Crowdsourced Subjective Quality Testing. Seufert, Michael; Hoßfeld, Tobias. In 5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS). Berlin, Germany, 2016.
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  Crowdsourcing studies for subjective quality testing have become a particularly useful tool for Quality of Experience researchers. Typically, crowdsouring studies are conducted by many unsupervised workers, which rate the perceived quality of several test conditions during one session (mixed within-subject test design). However, those studies often show to be very sensitive, for example, to test instructions, design, and filtering of unreliable participants. Moreover, the exposure of several test conditions to single workers potentially leads to an implicit training and anchoring of ratings. Therefore, this works investigates the extreme case of presenting only a single test condition to each worker (completely between-subjects test design). The results are compared to a typical crowdsourcing study design with multiple test conditions to discuss training effects in crowdsourcing studies. Thus, this work investigates if it is possible to use a simple ``one shot'' design with only one rating of a large number of workers instead of sophisticated (mixed or within-subject) test designs in crowdsourcing.

  @inproceedings{info3-inproceedings-2016-11, abstract = {Crowdsourcing studies for subjective quality testing have become a particularly useful tool for Quality of Experience researchers. Typically, crowdsouring studies are conducted by many unsupervised workers, which rate the perceived quality of several test conditions during one session (mixed within-subject test design). However, those studies often show to be very sensitive, for example, to test instructions, design, and filtering of unreliable participants. Moreover, the exposure of several test conditions to single workers potentially leads to an implicit training and anchoring of ratings. Therefore, this works investigates the extreme case of presenting only a single test condition to each worker (completely between-subjects test design). The results are compared to a typical crowdsourcing study design with multiple test conditions to discuss training effects in crowdsourcing studies. Thus, this work investigates if it is possible to use a simple ``one shot'' design with only one rating of a large number of workers instead of sophisticated (mixed or within-subject) test designs in crowdsourcing.}, address = {Berlin, Germany}, author = {Seufert, Michael and Hoßfeld, Tobias}, booktitle = {5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS)}, keywords = {can}, month = {08}, title = {One Shot Crowdtesting: Approaching the Extremes of Crowdsourced Subjective Quality Testing}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-11 %A Seufert, Michael %A Hoßfeld, Tobias %B 5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS) %C Berlin, Germany %D 2016 %T One Shot Crowdtesting: Approaching the Extremes of Crowdsourced Subjective Quality Testing %X Crowdsourcing studies for subjective quality testing have become a particularly useful tool for Quality of Experience researchers. Typically, crowdsouring studies are conducted by many unsupervised workers, which rate the perceived quality of several test conditions during one session (mixed within-subject test design). However, those studies often show to be very sensitive, for example, to test instructions, design, and filtering of unreliable participants. Moreover, the exposure of several test conditions to single workers potentially leads to an implicit training and anchoring of ratings. Therefore, this works investigates the extreme case of presenting only a single test condition to each worker (completely between-subjects test design). The results are compared to a typical crowdsourcing study design with multiple test conditions to discuss training effects in crowdsourcing studies. Thus, this work investigates if it is possible to use a simple ``one shot'' design with only one rating of a large number of workers instead of sophisticated (mixed or within-subject) test designs in crowdsourcing.

• YoMoApp: a Tool for Analyzing QoE of YouTube HTTP Adaptive Streaming in Mobile Networks. Wamser, Florian; Seufert, Michael; Casas, Pedro; Irmer, Ralf; Tran-Gia, Phuoc; Schatz, Raimund. In European Conference on Networks and Communications (EuCNC). Paris, France, 2015.
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  The performance of YouTube in mobile networks is crucial to network operators, who try to find a trade-off between cost-efficient handling of the huge traffic amounts and high perceived end-user Quality of Experience (QoE). This paper introduces YoMoApp (YouTube Performance Monitoring Application), an Android application, which passively monitors key performance indicators (KPIs) of YouTube adaptive video streaming on end-user smartphones. The monitored KPIs (i.e., player state/events, buffer, and video quality level) can be used to analyze the QoE of mobile YouTube video sessions. YoMoApp is a valuable tool to assess the performance of mobile networks with respect to YouTube traffic, as well as to develop optimizations and QoE models for mobile HTTP adaptive streaming. We test YoMoApp through real subjective QoE tests showing that the tool is accurate to capture the experience of end-users watching YouTube on smartphones.

  @inproceedings{info3-inproceedings-2015-513, abstract = {The performance of YouTube in mobile networks is crucial to network operators, who try to find a trade-off between cost-efficient handling of the huge traffic amounts and high perceived end-user Quality of Experience (QoE). This paper introduces YoMoApp (YouTube Performance Monitoring Application), an Android application, which passively monitors key performance indicators (KPIs) of YouTube adaptive video streaming on end-user smartphones. The monitored KPIs (i.e., player state/events, buffer, and video quality level) can be used to analyze the QoE of mobile YouTube video sessions. YoMoApp is a valuable tool to assess the performance of mobile networks with respect to YouTube traffic, as well as to develop optimizations and QoE models for mobile HTTP adaptive streaming. We test YoMoApp through real subjective QoE tests showing that the tool is accurate to capture the experience of end-users watching YouTube on smartphones.}, address = {Paris, France}, author = {Wamser, Florian and Seufert, Michael and Casas, Pedro and Irmer, Ralf and Tran-Gia, Phuoc and Schatz, Raimund}, booktitle = {European Conference on Networks and Communications (EuCNC)}, keywords = {demobenefit}, month = {06}, title = {YoMoApp: a Tool for Analyzing QoE of YouTube HTTP Adaptive Streaming in Mobile Networks}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-513 %A Wamser, Florian %A Seufert, Michael %A Casas, Pedro %A Irmer, Ralf %A Tran-Gia, Phuoc %A Schatz, Raimund %B European Conference on Networks and Communications (EuCNC) %C Paris, France %D 2015 %T YoMoApp: a Tool for Analyzing QoE of YouTube HTTP Adaptive Streaming in Mobile Networks %X The performance of YouTube in mobile networks is crucial to network operators, who try to find a trade-off between cost-efficient handling of the huge traffic amounts and high perceived end-user Quality of Experience (QoE). This paper introduces YoMoApp (YouTube Performance Monitoring Application), an Android application, which passively monitors key performance indicators (KPIs) of YouTube adaptive video streaming on end-user smartphones. The monitored KPIs (i.e., player state/events, buffer, and video quality level) can be used to analyze the QoE of mobile YouTube video sessions. YoMoApp is a valuable tool to assess the performance of mobile networks with respect to YouTube traffic, as well as to develop optimizations and QoE models for mobile HTTP adaptive streaming. We test YoMoApp through real subjective QoE tests showing that the tool is accurate to capture the experience of end-users watching YouTube on smartphones.
• Interaction of Control Loops on Application, Transport, and Network Layer. Zinner, Thomas; Cofano, Giuseppe; Wamser, Florian; De Cicco, Luca; Mascolo, Saverio; Tran-Gia, Phuoc. In EUCNC - Special Session 3 QoS/QoE Monitoring and Management with SDN. Paris, 2015.
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  @inproceedings{info3-inproceedings-2015-520, address = {Paris}, author = {Zinner, Thomas and Cofano, Giuseppe and Wamser, Florian and De Cicco, Luca and Mascolo, Saverio and Tran-Gia, Phuoc}, booktitle = {EUCNC - Special Session 3 QoS/QoE Monitoring and Management with SDN}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Interaction of Control Loops on Application, Transport, and Network Layer}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-520 %A Zinner, Thomas %A Cofano, Giuseppe %A Wamser, Florian %A De Cicco, Luca %A Mascolo, Saverio %A Tran-Gia, Phuoc %B EUCNC - Special Session 3 QoS/QoE Monitoring and Management with SDN %C Paris %D 2015 %T Interaction of Control Loops on Application, Transport, and Network Layer
• The Unexpected QoE Killer: When the Network Emulator Misshapes Traffic and QoE. Reichl, Peter; Egger, Sebastian; Möller, Sebastian; Kilkki, Kalevi; Fiedler, Markus; Hoßfeld, Tobias; Tsiaras, Christos; Asrese, Almnew. In 7th International Workshop on Quality of Multimedia Experience (QoMEX). 2015.
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  @inproceedings{info3-inproceedings-2015-30, author = {Reichl, Peter and Egger, Sebastian and Möller, Sebastian and Kilkki, Kalevi and Fiedler, Markus and Hoßfeld, Tobias and Tsiaras, Christos and Asrese, Almnew}, booktitle = {7th International Workshop on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {The Unexpected QoE Killer: When the Network Emulator Misshapes Traffic and QoE}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-30 %A Reichl, Peter %A Egger, Sebastian %A Möller, Sebastian %A Kilkki, Kalevi %A Fiedler, Markus %A Hoßfeld, Tobias %A Tsiaras, Christos %A Asrese, Almnew %B 7th International Workshop on Quality of Multimedia Experience (QoMEX) %D 2015 %T The Unexpected QoE Killer: When the Network Emulator Misshapes Traffic and QoE
• QoE in the Web: A Dance of Design and Performance. Varela, Martin; Skorin-Kapov, Lea; Mäki, Toni; Hoßfeld, Tobias. In 7th International Workshop on Quality of Multimedia Experience (QoMEX). Costa Navarino, Greece, 2015.
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  @inproceedings{info3-inproceedings-2015-33, address = {Costa Navarino, Greece}, author = {Varela, Martin and Skorin-Kapov, Lea and Mäki, Toni and Hoßfeld, Tobias}, booktitle = {7th International Workshop on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {QoE in the Web: A Dance of Design and Performance}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-33 %A Varela, Martin %A Skorin-Kapov, Lea %A Mäki, Toni %A Hoßfeld, Tobias %B 7th International Workshop on Quality of Multimedia Experience (QoMEX) %C Costa Navarino, Greece %D 2015 %T QoE in the Web: A Dance of Design and Performance
• QoE beyond the MOS: Added Value Using Quantiles and Distributions. Hoßfeld, Tobias; Heegaard, Poul E.; Varela, Martin. In 7th International Workshop on Quality of Multimedia Experience (QoMEX). Costa Navarino, Greece, 2015.
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  @inproceedings{info3-inproceedings-2015-32, address = {Costa Navarino, Greece}, author = {Hoßfeld, Tobias and Heegaard, Poul E. and Varela, Martin}, booktitle = {7th International Workshop on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {QoE beyond the MOS: Added Value Using Quantiles and Distributions}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-32 %A Hoßfeld, Tobias %A Heegaard, Poul E. %A Varela, Martin %B 7th International Workshop on Quality of Multimedia Experience (QoMEX) %C Costa Navarino, Greece %D 2015 %T QoE beyond the MOS: Added Value Using Quantiles and Distributions
• Can context monitoring improve QoE? A case study of video flash crowds in the Internet of Services. Hoßfeld, Tobias; Skorin-Kapov, Lea; Haddad, Yoram; Pocta, Peter; Siris, Vasilios; Zgank, Andrej; Melvin, Hugh. In Third IFIP/IEEE International Workshop on Quality of Experience Centric Management. Ottawa, Canada, 2015.
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  @inproceedings{info3-inproceedings-2015-34, address = {Ottawa, Canada}, author = {Hoßfeld, Tobias and Skorin-Kapov, Lea and Haddad, Yoram and Pocta, Peter and Siris, Vasilios and Zgank, Andrej and Melvin, Hugh}, booktitle = {Third IFIP/IEEE International Workshop on Quality of Experience Centric Management}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Can context monitoring improve QoE? A case study of video flash crowds in the Internet of Services}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-34 %A Hoßfeld, Tobias %A Skorin-Kapov, Lea %A Haddad, Yoram %A Pocta, Peter %A Siris, Vasilios %A Zgank, Andrej %A Melvin, Hugh %B Third IFIP/IEEE International Workshop on Quality of Experience Centric Management %C Ottawa, Canada %D 2015 %T Can context monitoring improve QoE? A case study of video flash crowds in the Internet of Services
• Investigating the Impact of Network Topology on the Processing Times of SDN Controllers. Metter, Christopher; Gebert, Steffen; Lange, Stanislav; Zinner, Thomas; Tran-Gia, Phuoc; Jarschel, Michael. In Seventh IFIP/IEEE International Workshop on Management of the Future Internet. Ottawa, Canada, 2015.
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  Software Defined Networking (SDN) introduces the concept of logically-centralized controllers in charge of managing the forwarding behavior of network elements. The new possibilities enabled through the centralization of control logic come with a certain risk: The controller might become a performance bottleneck. Therefore, ensuring sufficient controller performance is one of the crucial tasks prior to a successful SDN deployment. Furthermore, fine-grained traffic engineering, e.g., to achieve higher link utilization, results in a higher frequency of requests that are sent to the controller, which leads to an increased controller load. It is therefore important to analyze the capabilities of SDN controllers prior to deployment. This paper investigates two software implementations, the OpenDaylight and Ryu controllers. The control message throughput of different controllers has been studied several times already; however, it is not yet known what influence the number and topology of connected switches have. This paper investigates this influence in detail for a fat-tree data center topology and a WAN topology as well as 261 topologies with varying characteristics from the Internet Topology Zoo.

  @inproceedings{info3-inproceedings-2015-510, abstract = {Software Defined Networking (SDN) introduces the concept of logically-centralized controllers in charge of managing the forwarding behavior of network elements. The new possibilities enabled through the centralization of control logic come with a certain risk: The controller might become a performance bottleneck. Therefore, ensuring sufficient controller performance is one of the crucial tasks prior to a successful SDN deployment. Furthermore, fine-grained traffic engineering, e.g., to achieve higher link utilization, results in a higher frequency of requests that are sent to the controller, which leads to an increased controller load. It is therefore important to analyze the capabilities of SDN controllers prior to deployment. This paper investigates two software implementations, the OpenDaylight and Ryu controllers. The control message throughput of different controllers has been studied several times already; however, it is not yet known what influence the number and topology of connected switches have. This paper investigates this influence in detail for a fat-tree data center topology and a WAN topology as well as 261 topologies with varying characteristics from the Internet Topology Zoo.}, address = {Ottawa, Canada}, author = {Metter, Christopher and Gebert, Steffen and Lange, Stanislav and Zinner, Thomas and Tran-Gia, Phuoc and Jarschel, Michael}, booktitle = {Seventh IFIP/IEEE International Workshop on Management of the Future Internet}, keywords = {saser-siegfried}, month = {05}, title = {Investigating the Impact of Network Topology on the Processing Times of SDN Controllers}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-510 %A Metter, Christopher %A Gebert, Steffen %A Lange, Stanislav %A Zinner, Thomas %A Tran-Gia, Phuoc %A Jarschel, Michael %B Seventh IFIP/IEEE International Workshop on Management of the Future Internet %C Ottawa, Canada %D 2015 %T Investigating the Impact of Network Topology on the Processing Times of SDN Controllers %X Software Defined Networking (SDN) introduces the concept of logically-centralized controllers in charge of managing the forwarding behavior of network elements. The new possibilities enabled through the centralization of control logic come with a certain risk: The controller might become a performance bottleneck. Therefore, ensuring sufficient controller performance is one of the crucial tasks prior to a successful SDN deployment. Furthermore, fine-grained traffic engineering, e.g., to achieve higher link utilization, results in a higher frequency of requests that are sent to the controller, which leads to an increased controller load. It is therefore important to analyze the capabilities of SDN controllers prior to deployment. This paper investigates two software implementations, the OpenDaylight and Ryu controllers. The control message throughput of different controllers has been studied several times already; however, it is not yet known what influence the number and topology of connected switches have. This paper investigates this influence in detail for a fat-tree data center topology and a WAN topology as well as 261 topologies with varying characteristics from the Internet Topology Zoo.
• When the Crowd Challenges the Lab: Lessons Learnt from Subjective Studies on Image Aesthetic Appeal. Redi, Judith; Siahaan, Ernestasia; Korshunov, Pavel; Habigt, Julian; Hoßfeld, Tobias. In Fourth International Workshop on Crowdsourcing for Multimedia (CrowdMM). 2015.
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  @inproceedings{info3-inproceedings-2015-27, author = {Redi, Judith and Siahaan, Ernestasia and Korshunov, Pavel and Habigt, Julian and Hoßfeld, Tobias}, booktitle = {Fourth International Workshop on Crowdsourcing for Multimedia (CrowdMM)}, keywords = {sys:hidden:inproceedings}, title = {When the Crowd Challenges the Lab: Lessons Learnt from Subjective Studies on Image Aesthetic Appeal}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-27 %A Redi, Judith %A Siahaan, Ernestasia %A Korshunov, Pavel %A Habigt, Julian %A Hoßfeld, Tobias %B Fourth International Workshop on Crowdsourcing for Multimedia (CrowdMM) %D 2015 %T When the Crowd Challenges the Lab: Lessons Learnt from Subjective Studies on Image Aesthetic Appeal
• Journey through the crowd: Best Practices and Recommendations for Crowdsourced QoE. Hoßfeld, Tobias; Redi, Judith. In 7th International Workshop on Quality of Multimedia Experience (QoMEX). Costa Navarino, Greece, 2015.
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  @inproceedings{info3-inproceedings-2015-31, address = {Costa Navarino, Greece}, author = {Hoßfeld, Tobias and Redi, Judith}, booktitle = {7th International Workshop on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Journey through the crowd: Best Practices and Recommendations for Crowdsourced QoE}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-31 %A Hoßfeld, Tobias %A Redi, Judith %B 7th International Workshop on Quality of Multimedia Experience (QoMEX) %C Costa Navarino, Greece %D 2015 %T Journey through the crowd: Best Practices and Recommendations for Crowdsourced QoE
• To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior. Hoßfeld, Tobias; Moldovan, Christian; Schwartz, Christian. In Third IFIP/IEEE International Workshop on Quality of Experience Centric Management. Ottawa, Canada, 2015.
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  @inproceedings{info3-inproceedings-2015-35, address = {Ottawa, Canada}, author = {Hoßfeld, Tobias and Moldovan, Christian and Schwartz, Christian}, booktitle = {Third IFIP/IEEE International Workshop on Quality of Experience Centric Management}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-35 %A Hoßfeld, Tobias %A Moldovan, Christian %A Schwartz, Christian %B Third IFIP/IEEE International Workshop on Quality of Experience Centric Management %C Ottawa, Canada %D 2015 %T To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior
• Investigating Isolation between Virtual Networks in Case of Congestion for a Pronto 3290 Switch. Nguyen-Ngoc, Anh; Lange, Stanislav; Gebert, Steffen; Zinner, Thomas; Tran-Gia, Phuoc; Jarschel, Michael. In Workshop on Software-Defined Networking and Network Function Virtualization for Flexible Network Management (SDNFlex 2015). Cottbus, Germany, 2015.
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  Resource isolation between virtual networks is one of the key features of network virtualization. It is typically realized by configuring queues with specific rate guarantees on the egress ports of the network devices. The drawback of this architectural choice, however, is that traffic from several ingress ports may result in congestion on an egress port. Hence, the question arises to which extent isolation between virtual networks is realized in state-of-the-art hardware. This work aims at investigating whether congestion within one virtual network may affect the throughput performance of another virtual network. For that, measurements in a local testbed using a Pronto 3290 switch running an OpenFlow-enabling Pica8 firmware are performed.

  @inproceedings{info3-inproceedings-2015-508, abstract = {Resource isolation between virtual networks is one of the key features of network virtualization. It is typically realized by configuring queues with specific rate guarantees on the egress ports of the network devices. The drawback of this architectural choice, however, is that traffic from several ingress ports may result in congestion on an egress port. Hence, the question arises to which extent isolation between virtual networks is realized in state-of-the-art hardware. This work aims at investigating whether congestion within one virtual network may affect the throughput performance of another virtual network. For that, measurements in a local testbed using a Pronto 3290 switch running an OpenFlow-enabling Pica8 firmware are performed.}, address = {Cottbus, Germany}, author = {Nguyen-Ngoc, Anh and Lange, Stanislav and Gebert, Steffen and Zinner, Thomas and Tran-Gia, Phuoc and Jarschel, Michael}, booktitle = {Workshop on Software-Defined Networking and Network Function Virtualization for Flexible Network Management (SDNFlex 2015)}, keywords = {saser-siegfried}, month = {03}, title = {Investigating Isolation between Virtual Networks in Case of Congestion for a Pronto 3290 Switch}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-508 %A Nguyen-Ngoc, Anh %A Lange, Stanislav %A Gebert, Steffen %A Zinner, Thomas %A Tran-Gia, Phuoc %A Jarschel, Michael %B Workshop on Software-Defined Networking and Network Function Virtualization for Flexible Network Management (SDNFlex 2015) %C Cottbus, Germany %D 2015 %T Investigating Isolation between Virtual Networks in Case of Congestion for a Pronto 3290 Switch %X Resource isolation between virtual networks is one of the key features of network virtualization. It is typically realized by configuring queues with specific rate guarantees on the egress ports of the network devices. The drawback of this architectural choice, however, is that traffic from several ingress ports may result in congestion on an egress port. Hence, the question arises to which extent isolation between virtual networks is realized in state-of-the-art hardware. This work aims at investigating whether congestion within one virtual network may affect the throughput performance of another virtual network. For that, measurements in a local testbed using a Pronto 3290 switch running an OpenFlow-enabling Pica8 firmware are performed.
• Bridging the Gap Between Eye Tracking and Crowdsourcing. Lebreton, Pierre; Mäki, Toni; Skodras, Evangelos; Hupont Torres, Isabelle; Hirth, Matthias. In SPIE 9394, Human Vision and Electronic Imaging XX. San Francisco, USA, 2015.
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  Visual attention studies aim at understanding how people scan images or videos. However, these types of studies require dedicated equipment such as IR-based eye trackers, which can be highly expensive. Moreover, one of the challenges with visual attention studies is that they require a large amount of tests to go beyond individuals. They are time consuming, may be intrusive and require specific setup that can be only obtained in a laboratory environment. This paper proposes a novel framework enabling crowd-sourced eye tracking tests using a standard web-cam and web-based techniques, to collect visual attention information from the users while interacting with the contents in ecologically valid environments. The performance of the preliminary user tests is promising and paves the way for low-cost universal eye tracking.

  @inproceedings{info3-inproceedings-2015-505, abstract = {Visual attention studies aim at understanding how people scan images or videos. However, these types of studies require dedicated equipment such as IR-based eye trackers, which can be highly expensive. Moreover, one of the challenges with visual attention studies is that they require a large amount of tests to go beyond individuals. They are time consuming, may be intrusive and require specific setup that can be only obtained in a laboratory environment. This paper proposes a novel framework enabling crowd-sourced eye tracking tests using a standard web-cam and web-based techniques, to collect visual attention information from the users while interacting with the contents in ecologically valid environments. The performance of the preliminary user tests is promising and paves the way for low-cost universal eye tracking.}, address = {San Francisco, USA}, author = {Lebreton, Pierre and Mäki, Toni and Skodras, Evangelos and Hupont Torres, Isabelle and Hirth, Matthias}, booktitle = {SPIE 9394, Human Vision and Electronic Imaging XX}, keywords = {crowdsourcing-design}, month = {02}, title = {Bridging the Gap Between Eye Tracking and Crowdsourcing}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-505 %A Lebreton, Pierre %A Mäki, Toni %A Skodras, Evangelos %A Hupont Torres, Isabelle %A Hirth, Matthias %B SPIE 9394, Human Vision and Electronic Imaging XX %C San Francisco, USA %D 2015 %T Bridging the Gap Between Eye Tracking and Crowdsourcing %X Visual attention studies aim at understanding how people scan images or videos. However, these types of studies require dedicated equipment such as IR-based eye trackers, which can be highly expensive. Moreover, one of the challenges with visual attention studies is that they require a large amount of tests to go beyond individuals. They are time consuming, may be intrusive and require specific setup that can be only obtained in a laboratory environment. This paper proposes a novel framework enabling crowd-sourced eye tracking tests using a standard web-cam and web-based techniques, to collect visual attention information from the users while interacting with the contents in ecologically valid environments. The performance of the preliminary user tests is promising and paves the way for low-cost universal eye tracking.
• Do Scale-Design and Training Matter for Video QoE Assessments through Crowdsourcing?. Gardlo, Bruno; Egger, Sebastian; Hoßfeld, Tobias. In Fourth International Workshop on Crowdsourcing for Multimedia (CrowdMM). 2015.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2015-28, author = {Gardlo, Bruno and Egger, Sebastian and Hoßfeld, Tobias}, booktitle = {Fourth International Workshop on Crowdsourcing for Multimedia (CrowdMM)}, keywords = {sys:hidden:inproceedings}, title = {Do Scale-Design and Training Matter for Video QoE Assessments through Crowdsourcing?}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-28 %A Gardlo, Bruno %A Egger, Sebastian %A Hoßfeld, Tobias %B Fourth International Workshop on Crowdsourcing for Multimedia (CrowdMM) %D 2015 %T Do Scale-Design and Training Matter for Video QoE Assessments through Crowdsourcing?
• Towards a comprehensive framework for QoE and user behavior modelling. Reichl, Peter; Egger, Sebastian; Möller, Sebastian; Kilkki, Kalevi; Fiedler, Markus; Hoßfeld, Tobias; Tsiaras, Christos; Asrese, Alemnew. In 2015 Seventh International Workshop on Quality of Multimedia Experience (QoMEX). 2015.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2015-36, author = {Reichl, Peter and Egger, Sebastian and Möller, Sebastian and Kilkki, Kalevi and Fiedler, Markus and Hoßfeld, Tobias and Tsiaras, Christos and Asrese, Alemnew}, booktitle = {2015 Seventh International Workshop on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, title = {Towards a comprehensive framework for QoE and user behavior modelling}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-36 %A Reichl, Peter %A Egger, Sebastian %A Möller, Sebastian %A Kilkki, Kalevi %A Fiedler, Markus %A Hoßfeld, Tobias %A Tsiaras, Christos %A Asrese, Alemnew %B 2015 Seventh International Workshop on Quality of Multimedia Experience (QoMEX) %D 2015 %T Towards a comprehensive framework for QoE and user behavior modelling
• Impact of WiFi Offloading on Video Streaming QoE in Urban Environments. Burger, Valentin; Seufert, Michael; Kaup, Fabian; Wichtlhuber, Matthias; Hausheer, David; Tran-Gia, Phuoc. In IEEE Workshop on Quality of Experience-based Management for Future Internet Applications and Services (QoE-FI). London, UK, 2015.
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  Video streaming is the most popular application in today's mobile Internet and its growing demands and popularity put more and more load on cellular networks. In a recent trend to mitigate the cellular load, followed by many providers, users are offered to offload mobile connections to WiFi hotspots, which are predominately deployed in urban environments. In this work, we conduct a simulative performance evaluation of the impact of WiFi offloading on the Quality of Experience (QoE) of video streaming. The evaluation is based on connectivity measurements from a German city and uses a simple QoE model for estimating the perceived quality of video streaming. Our findings show that, despite its benefits for operators, offloading to WiFi has a negative impact on video streaming QoE for some users when 3G/4G coverage is available. Only in the case of 2G coverage, WiFi offloading can significantly improve the perceived quality for users.

  @inproceedings{info3-inproceedings-2015-511, abstract = {Video streaming is the most popular application in today's mobile Internet and its growing demands and popularity put more and more load on cellular networks. In a recent trend to mitigate the cellular load, followed by many providers, users are offered to offload mobile connections to WiFi hotspots, which are predominately deployed in urban environments. In this work, we conduct a simulative performance evaluation of the impact of WiFi offloading on the Quality of Experience (QoE) of video streaming. The evaluation is based on connectivity measurements from a German city and uses a simple QoE model for estimating the perceived quality of video streaming. Our findings show that, despite its benefits for operators, offloading to WiFi has a negative impact on video streaming QoE for some users when 3G/4G coverage is available. Only in the case of 2G coverage, WiFi offloading can significantly improve the perceived quality for users.}, address = {London, UK}, author = {Burger, Valentin and Seufert, Michael and Kaup, Fabian and Wichtlhuber, Matthias and Hausheer, David and Tran-Gia, Phuoc}, booktitle = {IEEE Workshop on Quality of Experience-based Management for Future Internet Applications and Services (QoE-FI)}, keywords = {smartenit}, month = {06}, title = {Impact of WiFi Offloading on Video Streaming QoE in Urban Environments}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-511 %A Burger, Valentin %A Seufert, Michael %A Kaup, Fabian %A Wichtlhuber, Matthias %A Hausheer, David %A Tran-Gia, Phuoc %B IEEE Workshop on Quality of Experience-based Management for Future Internet Applications and Services (QoE-FI) %C London, UK %D 2015 %T Impact of WiFi Offloading on Video Streaming QoE in Urban Environments %X Video streaming is the most popular application in today's mobile Internet and its growing demands and popularity put more and more load on cellular networks. In a recent trend to mitigate the cellular load, followed by many providers, users are offered to offload mobile connections to WiFi hotspots, which are predominately deployed in urban environments. In this work, we conduct a simulative performance evaluation of the impact of WiFi offloading on the Quality of Experience (QoE) of video streaming. The evaluation is based on connectivity measurements from a German city and uses a simple QoE model for estimating the perceived quality of video streaming. Our findings show that, despite its benefits for operators, offloading to WiFi has a negative impact on video streaming QoE for some users when 3G/4G coverage is available. Only in the case of 2G coverage, WiFi offloading can significantly improve the perceived quality for users.
• Utilizing Home Router Caches to Augment CDNs towards Information-Centric Networking. Seufert, Michael; Burger, Valentin; Wamser, Florian; Tran-Gia, Phuoc; Moldovan, Christian; Hoßfeld, Tobias. In European Conference on Networks and Communications (EuCNC). Paris, France, 2015.
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  To implement improved Quality of Service (QoS) and Quality of Experience (QoE) management for content-heavy services like video streaming, content has to be moved closer to the edge. The concept of information-centric networking (ICN) would be a prospective enabler but is currently not practically feasible yet. We propose a hierarchical caching architecture utilizing caches on home routers to augment existing content delivery network (CDN) infrastructure. This approach can be implemented via Software-defined Networking (SDN) and brings current CDNs closer towards ICN. Based on a simulation study, we confirm that our approach is able to serve content more locally, which results in QoS and QoE benefits for end users as well as inter-domain traffic savings for network operators.

  @inproceedings{info3-inproceedings-2015-514, abstract = {To implement improved Quality of Service (QoS) and Quality of Experience (QoE) management for content-heavy services like video streaming, content has to be moved closer to the edge. The concept of information-centric networking (ICN) would be a prospective enabler but is currently not practically feasible yet. We propose a hierarchical caching architecture utilizing caches on home routers to augment existing content delivery network (CDN) infrastructure. This approach can be implemented via Software-defined Networking (SDN) and brings current CDNs closer towards ICN. Based on a simulation study, we confirm that our approach is able to serve content more locally, which results in QoS and QoE benefits for end users as well as inter-domain traffic savings for network operators.}, address = {Paris, France}, author = {Seufert, Michael and Burger, Valentin and Wamser, Florian and Tran-Gia, Phuoc and Moldovan, Christian and Hoßfeld, Tobias}, booktitle = {European Conference on Networks and Communications (EuCNC)}, keywords = {can}, month = {06}, title = {Utilizing Home Router Caches to Augment CDNs towards Information-Centric Networking}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-514 %A Seufert, Michael %A Burger, Valentin %A Wamser, Florian %A Tran-Gia, Phuoc %A Moldovan, Christian %A Hoßfeld, Tobias %B European Conference on Networks and Communications (EuCNC) %C Paris, France %D 2015 %T Utilizing Home Router Caches to Augment CDNs towards Information-Centric Networking %X To implement improved Quality of Service (QoS) and Quality of Experience (QoE) management for content-heavy services like video streaming, content has to be moved closer to the edge. The concept of information-centric networking (ICN) would be a prospective enabler but is currently not practically feasible yet. We propose a hierarchical caching architecture utilizing caches on home routers to augment existing content delivery network (CDN) infrastructure. This approach can be implemented via Software-defined Networking (SDN) and brings current CDNs closer towards ICN. Based on a simulation study, we confirm that our approach is able to serve content more locally, which results in QoS and QoE benefits for end users as well as inter-domain traffic savings for network operators.
• Continuously Delivering Your Network (Short Paper). Gebert, Steffen; Schwartz, Christian; Zinner, Thomas; Tran-Gia, Phuoc. In IEEE/IFIP International Symposium on Integrated Network Management (IM). Ottawa, Canada, 2015.
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  Softwarization and cloudification of networks through software defined networking and network functions virtualisation promise a new degree of flexibility and agility. By moving logic from device firmware into software applications and applying software development mechanisms, innovation can be introduced with less effort. Concrete ways how to operate and orchestrate such systems are not yet defined. The process of making changes to a controller software or a virtualized network function in a production network without the risk of network disruption is not covered by literature. Complexity of systems brings the risk of unexpected side-effects and has so long been a show-stopper for administrators applying changes to networking devices. This paper suggests the adaption of the successful concept of continuous delivery into the software defined networking world. Test-driven development and automatic acceptance tests demonstrate that the software engineering community already found ways to ensure that changes do not break. Applied to network engineering, the adaption of continuous delivery can be seen as an enabler for risk-free and frequent changes in production infrastructure through push button deployments.

  @inproceedings{info3-inproceedings-2015-512, abstract = {Softwarization and cloudification of networks through software defined networking and network functions virtualisation promise a new degree of flexibility and agility. By moving logic from device firmware into software applications and applying software development mechanisms, innovation can be introduced with less effort. Concrete ways how to operate and orchestrate such systems are not yet defined. The process of making changes to a controller software or a virtualized network function in a production network without the risk of network disruption is not covered by literature. Complexity of systems brings the risk of unexpected side-effects and has so long been a show-stopper for administrators applying changes to networking devices. This paper suggests the adaption of the successful concept of continuous delivery into the software defined networking world. Test-driven development and automatic acceptance tests demonstrate that the software engineering community already found ways to ensure that changes do not break. Applied to network engineering, the adaption of continuous delivery can be seen as an enabler for risk-free and frequent changes in production infrastructure through push button deployments.}, address = {Ottawa, Canada}, author = {Gebert, Steffen and Schwartz, Christian and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {IEEE/IFIP International Symposium on Integrated Network Management (IM)}, keywords = {saser-siegfried}, month = {05}, title = {Continuously Delivering Your Network (Short Paper)}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-512 %A Gebert, Steffen %A Schwartz, Christian %A Zinner, Thomas %A Tran-Gia, Phuoc %B IEEE/IFIP International Symposium on Integrated Network Management (IM) %C Ottawa, Canada %D 2015 %T Continuously Delivering Your Network (Short Paper) %X Softwarization and cloudification of networks through software defined networking and network functions virtualisation promise a new degree of flexibility and agility. By moving logic from device firmware into software applications and applying software development mechanisms, innovation can be introduced with less effort. Concrete ways how to operate and orchestrate such systems are not yet defined. The process of making changes to a controller software or a virtualized network function in a production network without the risk of network disruption is not covered by literature. Complexity of systems brings the risk of unexpected side-effects and has so long been a show-stopper for administrators applying changes to networking devices. This paper suggests the adaption of the successful concept of continuous delivery into the software defined networking world. Test-driven development and automatic acceptance tests demonstrate that the software engineering community already found ways to ensure that changes do not break. Applied to network engineering, the adaption of continuous delivery can be seen as an enabler for risk-free and frequent changes in production infrastructure through push button deployments.
• Exploring QoE in Cellular Networks: How Much Bandwidth do you Need for Popular Smartphone Apps?. Casas, Pedro; Schatz, Raimund; Wamser, Florian; Seufert, Michael; Irmer, Ralf. In 5th ACM SIGCOMM Workshop on All Things Cellular: Operations, Applications and Challenges. London, UK, 2015.
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  A quarter of the world population will be using smartphones to access the Internet in the near future. In this context, understanding the Quality of Experience (QoE) of popular services in such devices becomes paramount for cellular network operators, who need to offer high quality levels to reduce the risks of customers churning for quality dissatisfaction. In this paper we study the problemof QoE provisioning in smartphones, presenting the results obtained from subjective lab tests performed for five popular apps: YouTube, Facebook, Web browsing through Chrome, Google Maps, and WhatsApp. The analysis addresses the impact of the access downlink bandwidth on the QoE of these apps when accessed through smartphones. The results presented in this paper provide a sound basis for better understanding the QoE requirements of popular services and mobile apps, as well as for dimensioning the underlying provisioning network. To the best of our knowledge, this is the first paper providing such a comprehensive analysis of QoE in mobile devices.

  @inproceedings{info3-inproceedings-2015-516, abstract = {A quarter of the world population will be using smartphones to access the Internet in the near future. In this context, understanding the Quality of Experience (QoE) of popular services in such devices becomes paramount for cellular network operators, who need to offer high quality levels to reduce the risks of customers churning for quality dissatisfaction. In this paper we study the problemof QoE provisioning in smartphones, presenting the results obtained from subjective lab tests performed for five popular apps: YouTube, Facebook, Web browsing through Chrome, Google Maps, and WhatsApp. The analysis addresses the impact of the access downlink bandwidth on the QoE of these apps when accessed through smartphones. The results presented in this paper provide a sound basis for better understanding the QoE requirements of popular services and mobile apps, as well as for dimensioning the underlying provisioning network. To the best of our knowledge, this is the first paper providing such a comprehensive analysis of QoE in mobile devices.}, address = {London, UK}, author = {Casas, Pedro and Schatz, Raimund and Wamser, Florian and Seufert, Michael and Irmer, Ralf}, booktitle = {5th ACM SIGCOMM Workshop on All Things Cellular: Operations, Applications and Challenges}, keywords = {can}, month = {08}, title = {Exploring QoE in Cellular Networks: How Much Bandwidth do you Need for Popular Smartphone Apps?}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-516 %A Casas, Pedro %A Schatz, Raimund %A Wamser, Florian %A Seufert, Michael %A Irmer, Ralf %B 5th ACM SIGCOMM Workshop on All Things Cellular: Operations, Applications and Challenges %C London, UK %D 2015 %T Exploring QoE in Cellular Networks: How Much Bandwidth do you Need for Popular Smartphone Apps? %X A quarter of the world population will be using smartphones to access the Internet in the near future. In this context, understanding the Quality of Experience (QoE) of popular services in such devices becomes paramount for cellular network operators, who need to offer high quality levels to reduce the risks of customers churning for quality dissatisfaction. In this paper we study the problemof QoE provisioning in smartphones, presenting the results obtained from subjective lab tests performed for five popular apps: YouTube, Facebook, Web browsing through Chrome, Google Maps, and WhatsApp. The analysis addresses the impact of the access downlink bandwidth on the QoE of these apps when accessed through smartphones. The results presented in this paper provide a sound basis for better understanding the QoE requirements of popular services and mobile apps, as well as for dimensioning the underlying provisioning network. To the best of our knowledge, this is the first paper providing such a comprehensive analysis of QoE in mobile devices.
• Eye Tracker in the Wild: Studying the Delta Between What is Said and Measured in a Crowdsourcing Experiment. Lebreton, Pierre; Hupont Torres, Isabelle; Mäki, Toni; Skodras, Evangelos; Hirth, Matthias. In Workshop on Crowdsourcing for Multimedia (CrowdMM). Brisbane, Australia, 2015.
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  Self-reported metrics collected in crowdsourcing experiments do not always match the actual user behaviour. Therefore in the laboratory studies the visual attention, the capability of humans to selectively process the visual information with which they are confronted, is traditionally measured by means of eye trackers. Visual attention has not been typically considered in crowdsourcing environments, mainly because of the requirements of specific hardware and challenging gaze calibration. This paper proposes the use of a non- intrusive eye tracking crowdsourcing framework, where the only technical requirements from the users’ side are a web- cam and a HTML5 compatible web browser, to study the differences between what a participant implicitly and explicitly does during a crowdsourcing experiment. To demonstrate the feasibility of this approach, an exemplary crowdsourcing campaign was launched to collect and compare both eye tracking data and self-reported metrics from the users. Participants performed a movie selection task, where they were asked about the main reasons motivating them to choose a particular movie. Results demonstrate the added value of monitoring gaze in crowdsourcing contexts: consciously or not, users behave differently than what they report through questionnaires.

  @inproceedings{info3-inproceedings-2015-528, abstract = {Self-reported metrics collected in crowdsourcing experiments do not always match the actual user behaviour. Therefore in the laboratory studies the visual attention, the capability of humans to selectively process the visual information with which they are confronted, is traditionally measured by means of eye trackers. Visual attention has not been typically considered in crowdsourcing environments, mainly because of the requirements of specific hardware and challenging gaze calibration. This paper proposes the use of a non- intrusive eye tracking crowdsourcing framework, where the only technical requirements from the users’ side are a web- cam and a HTML5 compatible web browser, to study the differences between what a participant implicitly and explicitly does during a crowdsourcing experiment. To demonstrate the feasibility of this approach, an exemplary crowdsourcing campaign was launched to collect and compare both eye tracking data and self-reported metrics from the users. Participants performed a movie selection task, where they were asked about the main reasons motivating them to choose a particular movie. Results demonstrate the added value of monitoring gaze in crowdsourcing contexts: consciously or not, users behave differently than what they report through questionnaires.}, address = {Brisbane, Australia}, author = {Lebreton, Pierre and Hupont Torres, Isabelle and Mäki, Toni and Skodras, Evangelos and Hirth, Matthias}, booktitle = {Workshop on Crowdsourcing for Multimedia (CrowdMM)}, keywords = {crowdsourcing-design}, month = 10, title = {Eye Tracker in the Wild: Studying the Delta Between What is Said and Measured in a Crowdsourcing Experiment}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-528 %A Lebreton, Pierre %A Hupont Torres, Isabelle %A Mäki, Toni %A Skodras, Evangelos %A Hirth, Matthias %B Workshop on Crowdsourcing for Multimedia (CrowdMM) %C Brisbane, Australia %D 2015 %T Eye Tracker in the Wild: Studying the Delta Between What is Said and Measured in a Crowdsourcing Experiment %X Self-reported metrics collected in crowdsourcing experiments do not always match the actual user behaviour. Therefore in the laboratory studies the visual attention, the capability of humans to selectively process the visual information with which they are confronted, is traditionally measured by means of eye trackers. Visual attention has not been typically considered in crowdsourcing environments, mainly because of the requirements of specific hardware and challenging gaze calibration. This paper proposes the use of a non- intrusive eye tracking crowdsourcing framework, where the only technical requirements from the users’ side are a web- cam and a HTML5 compatible web browser, to study the differences between what a participant implicitly and explicitly does during a crowdsourcing experiment. To demonstrate the feasibility of this approach, an exemplary crowdsourcing campaign was launched to collect and compare both eye tracking data and self-reported metrics from the users. Participants performed a movie selection task, where they were asked about the main reasons motivating them to choose a particular movie. Results demonstrate the added value of monitoring gaze in crowdsourcing contexts: consciously or not, users behave differently than what they report through questionnaires.
• YouTube QoE on Mobile Devices: Subjective Analysis of Classical vs. Adaptive Video Streaming. Seufert, Michael; Wamser, Florian; Casas, Pedro; Irmer, Ralf; Tran-Gia, Phuoc; Schatz, Raimund. In 6th International Workshop on Traffic Analysis and Characterization (TRAC). Dubrovnik, Croatia, 2015.
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  YouTube is the most popular service in the Internet and is increasingly consumed on mobile devices. With emerging adaptive video streaming technology, the question arises whether it should be also employed in the mobile context, which shows different characteristics in terms of display sizes and reliability of Internet connection. This paper compares YouTube QoE on mobile devices for both classical and adaptive video streaming based on a subjective lab experiment, in which different network conditions were emulated. Our results show that adaptive video streaming provides almost excellent results for the poorest network conditions. Thereby, it clearly outperforms classical video streaming, and thus, should be considered to achieve higher QoE in future mobile streaming applications.

  @inproceedings{info3-inproceedings-2015-515, abstract = {YouTube is the most popular service in the Internet and is increasingly consumed on mobile devices. With emerging adaptive video streaming technology, the question arises whether it should be also employed in the mobile context, which shows different characteristics in terms of display sizes and reliability of Internet connection. This paper compares YouTube QoE on mobile devices for both classical and adaptive video streaming based on a subjective lab experiment, in which different network conditions were emulated. Our results show that adaptive video streaming provides almost excellent results for the poorest network conditions. Thereby, it clearly outperforms classical video streaming, and thus, should be considered to achieve higher QoE in future mobile streaming applications.}, address = {Dubrovnik, Croatia}, author = {Seufert, Michael and Wamser, Florian and Casas, Pedro and Irmer, Ralf and Tran-Gia, Phuoc and Schatz, Raimund}, booktitle = {6th International Workshop on Traffic Analysis and Characterization (TRAC)}, keywords = {can}, month = {08}, title = {YouTube QoE on Mobile Devices: Subjective Analysis of Classical vs. Adaptive Video Streaming}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-515 %A Seufert, Michael %A Wamser, Florian %A Casas, Pedro %A Irmer, Ralf %A Tran-Gia, Phuoc %A Schatz, Raimund %B 6th International Workshop on Traffic Analysis and Characterization (TRAC) %C Dubrovnik, Croatia %D 2015 %T YouTube QoE on Mobile Devices: Subjective Analysis of Classical vs. Adaptive Video Streaming %X YouTube is the most popular service in the Internet and is increasingly consumed on mobile devices. With emerging adaptive video streaming technology, the question arises whether it should be also employed in the mobile context, which shows different characteristics in terms of display sizes and reliability of Internet connection. This paper compares YouTube QoE on mobile devices for both classical and adaptive video streaming based on a subjective lab experiment, in which different network conditions were emulated. Our results show that adaptive video streaming provides almost excellent results for the poorest network conditions. Thereby, it clearly outperforms classical video streaming, and thus, should be considered to achieve higher QoE in future mobile streaming applications.
• Taming QoE in Cellular Networks: from Subjective Lab Studies to Measurements in the Field. Casas, Pedro; Gardlo, Bruno; Seufert, Michael; Wamser, Florian; Schatz, Raimund. In 11th International Conference on Network and Service Management (CNSM). Barcelona, Spain, 2015.
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  A quarter of the world population will be using smartphones to access the Internet in the near future. In this context, understanding the Quality of Experience (QoE) of popular apps in such devices becomes paramount to cellular network operators, who need to offer high quality levels to reduce the risks of customers churning for quality dissatisfaction. In this paper we address the problem of QoE provisioning in smartphones from a double perspective, combining the results obtained from subjective lab tests with end-device passive measurements and QoE crowd-sourced feedback obtained in operational cellular networks. The study addresses the impact of the downlink bandwidth on the QoE of three popular smartphone apps: YouTube, Facebook and Google Maps. As a main contribution, we show that the results obtained in the lab are highly applicable in the live scenario, as mappings track the QoE provided by users in real networks. We additionally provide hints and bandwidth thresholds for good QoE levels on such apps, as well as discussion on end-device passive measurements and analysis. The results presented in this paper provide a sound basis to better understand the QoE requirements of popular mobile apps, as well as for monitoring the underlying provisioning network. To the best of our knowledge, this is the first paper providing such a comprehensive analysis of QoE in mobile devices, combining network measurements with users QoE feedback in lab tests and operational networks.

  @inproceedings{info3-inproceedings-2015-531, abstract = {A quarter of the world population will be using smartphones to access the Internet in the near future. In this context, understanding the Quality of Experience (QoE) of popular apps in such devices becomes paramount to cellular network operators, who need to offer high quality levels to reduce the risks of customers churning for quality dissatisfaction. In this paper we address the problem of QoE provisioning in smartphones from a double perspective, combining the results obtained from subjective lab tests with end-device passive measurements and QoE crowd-sourced feedback obtained in operational cellular networks. The study addresses the impact of the downlink bandwidth on the QoE of three popular smartphone apps: YouTube, Facebook and Google Maps. As a main contribution, we show that the results obtained in the lab are highly applicable in the live scenario, as mappings track the QoE provided by users in real networks. We additionally provide hints and bandwidth thresholds for good QoE levels on such apps, as well as discussion on end-device passive measurements and analysis. The results presented in this paper provide a sound basis to better understand the QoE requirements of popular mobile apps, as well as for monitoring the underlying provisioning network. To the best of our knowledge, this is the first paper providing such a comprehensive analysis of QoE in mobile devices, combining network measurements with users QoE feedback in lab tests and operational networks.}, address = {Barcelona, Spain}, author = {Casas, Pedro and Gardlo, Bruno and Seufert, Michael and Wamser, Florian and Schatz, Raimund}, booktitle = {11th International Conference on Network and Service Management (CNSM)}, keywords = {can}, month = 11, title = {Taming QoE in Cellular Networks: from Subjective Lab Studies to Measurements in the Field}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-531 %A Casas, Pedro %A Gardlo, Bruno %A Seufert, Michael %A Wamser, Florian %A Schatz, Raimund %B 11th International Conference on Network and Service Management (CNSM) %C Barcelona, Spain %D 2015 %T Taming QoE in Cellular Networks: from Subjective Lab Studies to Measurements in the Field %X A quarter of the world population will be using smartphones to access the Internet in the near future. In this context, understanding the Quality of Experience (QoE) of popular apps in such devices becomes paramount to cellular network operators, who need to offer high quality levels to reduce the risks of customers churning for quality dissatisfaction. In this paper we address the problem of QoE provisioning in smartphones from a double perspective, combining the results obtained from subjective lab tests with end-device passive measurements and QoE crowd-sourced feedback obtained in operational cellular networks. The study addresses the impact of the downlink bandwidth on the QoE of three popular smartphone apps: YouTube, Facebook and Google Maps. As a main contribution, we show that the results obtained in the lab are highly applicable in the live scenario, as mappings track the QoE provided by users in real networks. We additionally provide hints and bandwidth thresholds for good QoE levels on such apps, as well as discussion on end-device passive measurements and analysis. The results presented in this paper provide a sound basis to better understand the QoE requirements of popular mobile apps, as well as for monitoring the underlying provisioning network. To the best of our knowledge, this is the first paper providing such a comprehensive analysis of QoE in mobile devices, combining network measurements with users QoE feedback in lab tests and operational networks.
• Performance Benchmarking of a Software-Based LTE SGW. Lange, Stanislav; Nguyen-Ngoc, Anh; Gebert, Steffen; Zinner, Thomas; Jarschel, Michael; Koepsel, Andreas; Sune, Marc; Raumer, Daniel; Gallenmüller, Sebastian; Carle, Georg; Tran-Gia, Phuoc. In 2nd International Workshop on Management of SDN and NFV Systems. Barcelona, Spain, 2015.
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  Network Functions Virtualization (NFV) is a concept that aims at providing network operators with benefits in terms of cost, flexibility, and vendor independence by utilizing virtualization techniques to run network functions as software on commercial off-the-shelf (COTS) hardware. In contrast, prior solutions rely on specialized hardware for each function. Performance evaluation of such systems usually requires a dedicated testbed for each individual component. Rather than analyzing these proprietary black-box components, Virtualized Network Functions (VNFs) are pieces of software that run on COTS hardware and whose properties can be investigated in a generic testbed. However, depending on the underlying hardware, operating system, and implementation, VNFs might behave differently. Therefore, mechanisms for the performance evaluation of VNFs should be similar to benchmarking of software, where different implementations are compared by applying them to predefined test cases and scenarios. This work presents a first step towards a benchmarking framework for VNFs. Given two different implementations of a VNF that acts as LTE Serving Gateway (SGW), influence factors and key performance indicators are identified and a comparison between the two mechanisms is drawn.

  @inproceedings{info3-inproceedings-2015-533, abstract = {Network Functions Virtualization (NFV) is a concept that aims at providing network operators with benefits in terms of cost, flexibility, and vendor independence by utilizing virtualization techniques to run network functions as software on commercial off-the-shelf (COTS) hardware. In contrast, prior solutions rely on specialized hardware for each function. Performance evaluation of such systems usually requires a dedicated testbed for each individual component. Rather than analyzing these proprietary black-box components, Virtualized Network Functions (VNFs) are pieces of software that run on COTS hardware and whose properties can be investigated in a generic testbed. However, depending on the underlying hardware, operating system, and implementation, VNFs might behave differently. Therefore, mechanisms for the performance evaluation of VNFs should be similar to benchmarking of software, where different implementations are compared by applying them to predefined test cases and scenarios. This work presents a first step towards a benchmarking framework for VNFs. Given two different implementations of a VNF that acts as LTE Serving Gateway (SGW), influence factors and key performance indicators are identified and a comparison between the two mechanisms is drawn.}, address = {Barcelona, Spain}, author = {Lange, Stanislav and Nguyen-Ngoc, Anh and Gebert, Steffen and Zinner, Thomas and Jarschel, Michael and Koepsel, Andreas and Sune, Marc and Raumer, Daniel and Gallenmüller, Sebastian and Carle, Georg and Tran-Gia, Phuoc}, booktitle = {2nd International Workshop on Management of SDN and NFV Systems}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Performance Benchmarking of a Software-Based LTE SGW}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-533 %A Lange, Stanislav %A Nguyen-Ngoc, Anh %A Gebert, Steffen %A Zinner, Thomas %A Jarschel, Michael %A Koepsel, Andreas %A Sune, Marc %A Raumer, Daniel %A Gallenmüller, Sebastian %A Carle, Georg %A Tran-Gia, Phuoc %B 2nd International Workshop on Management of SDN and NFV Systems %C Barcelona, Spain %D 2015 %T Performance Benchmarking of a Software-Based LTE SGW %X Network Functions Virtualization (NFV) is a concept that aims at providing network operators with benefits in terms of cost, flexibility, and vendor independence by utilizing virtualization techniques to run network functions as software on commercial off-the-shelf (COTS) hardware. In contrast, prior solutions rely on specialized hardware for each function. Performance evaluation of such systems usually requires a dedicated testbed for each individual component. Rather than analyzing these proprietary black-box components, Virtualized Network Functions (VNFs) are pieces of software that run on COTS hardware and whose properties can be investigated in a generic testbed. However, depending on the underlying hardware, operating system, and implementation, VNFs might behave differently. Therefore, mechanisms for the performance evaluation of VNFs should be similar to benchmarking of software, where different implementations are compared by applying them to predefined test cases and scenarios. This work presents a first step towards a benchmarking framework for VNFs. Given two different implementations of a VNF that acts as LTE Serving Gateway (SGW), influence factors and key performance indicators are identified and a comparison between the two mechanisms is drawn.
• Impact of Intermediate Layer on Quality of Experience of HTTP Adaptive Streaming. Seufert, Michael; Hoßfeld, Tobias; Sieber, Christian. In 11th International Conference on Network and Service Management (CNSM). Barcelona, Spain, 2015.
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  HTTP Adaptive Streaming (HAS) adapts the video quality to the current network condition by switching between different quality layers. As HAS was shown to perform better than classical video streaming, it is becoming increasingly popular. Recent research showed that quality switch amplitude and time on layer have an impact on the Quality of Experience (QoE) of HAS. However, those studies focused only on adaptation between two layers so far. This work extends these findings by taking adaptation between three layers into account. Thereby, especially the impact of an intermediate layer on user perceived quality is investigated. Crowdsourcing experiments were conducted in order to collect subjective ratings for adaptation between three layers. The results indicate that the quality of each layer and the time on each layer are important QoE parameters. This encourages the usage of temporal pooling approaches for QoE prediction and QoE-aware traffic management. Therefore, mean pooling of per-frame metrics will be applied and its performance will be validated with the subjective crowdsourcing results.

  @inproceedings{info3-inproceedings-2015-532, abstract = {HTTP Adaptive Streaming (HAS) adapts the video quality to the current network condition by switching between different quality layers. As HAS was shown to perform better than classical video streaming, it is becoming increasingly popular. Recent research showed that quality switch amplitude and time on layer have an impact on the Quality of Experience (QoE) of HAS. However, those studies focused only on adaptation between two layers so far. This work extends these findings by taking adaptation between three layers into account. Thereby, especially the impact of an intermediate layer on user perceived quality is investigated. Crowdsourcing experiments were conducted in order to collect subjective ratings for adaptation between three layers. The results indicate that the quality of each layer and the time on each layer are important QoE parameters. This encourages the usage of temporal pooling approaches for QoE prediction and QoE-aware traffic management. Therefore, mean pooling of per-frame metrics will be applied and its performance will be validated with the subjective crowdsourcing results.}, address = {Barcelona, Spain}, author = {Seufert, Michael and Hoßfeld, Tobias and Sieber, Christian}, booktitle = {11th International Conference on Network and Service Management (CNSM)}, keywords = {can}, month = 11, title = {Impact of Intermediate Layer on Quality of Experience of HTTP Adaptive Streaming}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-532 %A Seufert, Michael %A Hoßfeld, Tobias %A Sieber, Christian %B 11th International Conference on Network and Service Management (CNSM) %C Barcelona, Spain %D 2015 %T Impact of Intermediate Layer on Quality of Experience of HTTP Adaptive Streaming %X HTTP Adaptive Streaming (HAS) adapts the video quality to the current network condition by switching between different quality layers. As HAS was shown to perform better than classical video streaming, it is becoming increasingly popular. Recent research showed that quality switch amplitude and time on layer have an impact on the Quality of Experience (QoE) of HAS. However, those studies focused only on adaptation between two layers so far. This work extends these findings by taking adaptation between three layers into account. Thereby, especially the impact of an intermediate layer on user perceived quality is investigated. Crowdsourcing experiments were conducted in order to collect subjective ratings for adaptation between three layers. The results indicate that the quality of each layer and the time on each layer are important QoE parameters. This encourages the usage of temporal pooling approaches for QoE prediction and QoE-aware traffic management. Therefore, mean pooling of per-frame metrics will be applied and its performance will be validated with the subjective crowdsourcing results.
• Trade-Off between QoE and Operational Cost in Edge Resource Supported Video Streaming. Burger, Valentin; Darzanos, George; Papafili, Ioanna; Seufert, Michael. In 10th International Conference on P2P, Parallel, Grid, Cloud and Internet Computing (3PGCIC). Krakow, Poland, 2015.
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  The largest share of today`s consumer Internet traffic is video streaming and its demand on content delivery networks is continuously growing. To cope with the increasing demand of video streaming, recent work proposes mitigating end-user equipment to support content delivery at the edge of the network. The throughput of end-user equipment supporting content delivery is limited by the uplink of the users Internet connection.Especially for video streaming insufficient throughput causes the video to stall and affects the Quality of Experience (QoE) of end-users.To prevent video streams from stalling, we consider a tiered caching architecture, which requests higher tier caches to support content delivery, if the uplink throughput drops below a certain threshold. We conduct a simulative performance evaluation of the mechanism to investigate its impact on the QoE of end-users. Our results show that especially if the upload bandwidth of end-user equipment is low the setting of the threshold has a high impact. This can be used by operators to achieve the desired trade-off between QoE and operational cost for cache resources.

  @inproceedings{info3-inproceedings-2015-530, abstract = {The largest share of today`s consumer Internet traffic is video streaming and its demand on content delivery networks is continuously growing. To cope with the increasing demand of video streaming, recent work proposes mitigating end-user equipment to support content delivery at the edge of the network. The throughput of end-user equipment supporting content delivery is limited by the uplink of the users Internet connection.Especially for video streaming insufficient throughput causes the video to stall and affects the Quality of Experience (QoE) of end-users.To prevent video streams from stalling, we consider a tiered caching architecture, which requests higher tier caches to support content delivery, if the uplink throughput drops below a certain threshold. We conduct a simulative performance evaluation of the mechanism to investigate its impact on the QoE of end-users. Our results show that especially if the upload bandwidth of end-user equipment is low the setting of the threshold has a high impact. This can be used by operators to achieve the desired trade-off between QoE and operational cost for cache resources.}, address = {Krakow, Poland}, author = {Burger, Valentin and Darzanos, George and Papafili, Ioanna and Seufert, Michael}, booktitle = {10th International Conference on P2P, Parallel, Grid, Cloud and Internet Computing (3PGCIC)}, keywords = {can}, month = 11, title = {Trade-Off between QoE and Operational Cost in Edge Resource Supported Video Streaming}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-530 %A Burger, Valentin %A Darzanos, George %A Papafili, Ioanna %A Seufert, Michael %B 10th International Conference on P2P, Parallel, Grid, Cloud and Internet Computing (3PGCIC) %C Krakow, Poland %D 2015 %T Trade-Off between QoE and Operational Cost in Edge Resource Supported Video Streaming %X The largest share of today`s consumer Internet traffic is video streaming and its demand on content delivery networks is continuously growing. To cope with the increasing demand of video streaming, recent work proposes mitigating end-user equipment to support content delivery at the edge of the network. The throughput of end-user equipment supporting content delivery is limited by the uplink of the users Internet connection.Especially for video streaming insufficient throughput causes the video to stall and affects the Quality of Experience (QoE) of end-users.To prevent video streams from stalling, we consider a tiered caching architecture, which requests higher tier caches to support content delivery, if the uplink throughput drops below a certain threshold. We conduct a simulative performance evaluation of the mechanism to investigate its impact on the QoE of end-users. Our results show that especially if the upload bandwidth of end-user equipment is low the setting of the threshold has a high impact. This can be used by operators to achieve the desired trade-off between QoE and operational cost for cache resources.
• MicroTrails: Comparing Hypotheses about Task Selection on a Crowd Sourcing Platform. Becker, Martin; Borchert, Kathrin; Hirth, Matthias; Mewes, Hauke; Hotho, Andreas; Tran-Gia, Phuoc. In International Conference on Knowledge Technologies and Data-driven Business (I-KNOW). Graz, Austria, 2015.
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  To optimize the workflow on commercial crowdsourcing platforms like Amazon Mechanical Turk or Microworkers, it is important to understand how users choose their tasks. Current work usually explores the underlying processes by employing user studies based on surveys with a limited set of participants. In contrast, we formulate hypotheses based on the different findings in these studies and, in- stead of verifying them based on user feedback, we compare them directly on data from a commercial crowdsourcing platform. For evaluation, we use a Bayesian approach called HypTrails which allows us to give a relative ranking of the corresponding hypotheses. The hypotheses considered, are for example based on task categories, monetary incentives or semantic similarity of task descriptions. We find that, in our scenario, hypotheses based on employers as well the the task descriptions work best. Overall, we objectively compare different factors influencing users when choosing their tasks. Our approach enables crowdsourcing companies to better understand their users in order to optimize their platforms, e.g., by incorporating the gained knowledge about these factors into task recommendation systems.

  @inproceedings{info3-inproceedings-2015-526, abstract = {To optimize the workflow on commercial crowdsourcing platforms like Amazon Mechanical Turk or Microworkers, it is important to understand how users choose their tasks. Current work usually explores the underlying processes by employing user studies based on surveys with a limited set of participants. In contrast, we formulate hypotheses based on the different findings in these studies and, in- stead of verifying them based on user feedback, we compare them directly on data from a commercial crowdsourcing platform. For evaluation, we use a Bayesian approach called HypTrails which allows us to give a relative ranking of the corresponding hypotheses. The hypotheses considered, are for example based on task categories, monetary incentives or semantic similarity of task descriptions. We find that, in our scenario, hypotheses based on employers as well the the task descriptions work best. Overall, we objectively compare different factors influencing users when choosing their tasks. Our approach enables crowdsourcing companies to better understand their users in order to optimize their platforms, e.g., by incorporating the gained knowledge about these factors into task recommendation systems.}, address = {Graz, Austria}, author = {Becker, Martin and Borchert, Kathrin and Hirth, Matthias and Mewes, Hauke and Hotho, Andreas and Tran-Gia, Phuoc}, booktitle = {International Conference on Knowledge Technologies and Data-driven Business (I-KNOW)}, keywords = {crowdsourcing-design}, month = 10, title = {MicroTrails: Comparing Hypotheses about Task Selection on a Crowd Sourcing Platform}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-526 %A Becker, Martin %A Borchert, Kathrin %A Hirth, Matthias %A Mewes, Hauke %A Hotho, Andreas %A Tran-Gia, Phuoc %B International Conference on Knowledge Technologies and Data-driven Business (I-KNOW) %C Graz, Austria %D 2015 %T MicroTrails: Comparing Hypotheses about Task Selection on a Crowd Sourcing Platform %X To optimize the workflow on commercial crowdsourcing platforms like Amazon Mechanical Turk or Microworkers, it is important to understand how users choose their tasks. Current work usually explores the underlying processes by employing user studies based on surveys with a limited set of participants. In contrast, we formulate hypotheses based on the different findings in these studies and, in- stead of verifying them based on user feedback, we compare them directly on data from a commercial crowdsourcing platform. For evaluation, we use a Bayesian approach called HypTrails which allows us to give a relative ranking of the corresponding hypotheses. The hypotheses considered, are for example based on task categories, monetary incentives or semantic similarity of task descriptions. We find that, in our scenario, hypotheses based on employers as well the the task descriptions work best. Overall, we objectively compare different factors influencing users when choosing their tasks. Our approach enables crowdsourcing companies to better understand their users in order to optimize their platforms, e.g., by incorporating the gained knowledge about these factors into task recommendation systems.
• Augmenting Home Routers for Socially-Aware Traffic Management. Lareida, Andri; Petropoulos, George; Burger, Valentin; Seufert, Michael; Soursos, Sergios; Stiller, Burkhard. In 40th Annual IEEE Conference on Local Computer Networks (LCN). Clearwater Beach, FL, USA, 2015.
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  Mobile users' Quality-of-Experience (QoE) is degrading as network usage increases while Internet Service Providers (ISP) face increased inter-domain traffic. This paper presents a network traffic management mechanism, named RB-HORST, addressing these inefficiencies. RB-HORST exploits home routers by using them as caches and forming an overlay network between them to transfer content. To shift traffic from peak hours, RB-HORST employs predictions based on social network properties and based on similarity in the overlay network. To further improve user QoE, home routers allow trusted mobile devices to offload their mobile connection to the local WiFi. Simulation results show that an overlay is imperative for the success of the proposed caching mechanism. Especially ISPs with a large number of customers can benefit if only every thousandth user shares its router, reducing inter-domain traffic by half and superseding an ISP operated cache. The presented implementation proves that the concept is technically feasible and can be deployed and run on constrained devices.

  @inproceedings{info3-inproceedings-2015-518, abstract = {Mobile users' Quality-of-Experience (QoE) is degrading as network usage increases while Internet Service Providers (ISP) face increased inter-domain traffic. This paper presents a network traffic management mechanism, named RB-HORST, addressing these inefficiencies. RB-HORST exploits home routers by using them as caches and forming an overlay network between them to transfer content. To shift traffic from peak hours, RB-HORST employs predictions based on social network properties and based on similarity in the overlay network. To further improve user QoE, home routers allow trusted mobile devices to offload their mobile connection to the local WiFi. Simulation results show that an overlay is imperative for the success of the proposed caching mechanism. Especially ISPs with a large number of customers can benefit if only every thousandth user shares its router, reducing inter-domain traffic by half and superseding an ISP operated cache. The presented implementation proves that the concept is technically feasible and can be deployed and run on constrained devices.}, address = {Clearwater Beach, FL, USA}, author = {Lareida, Andri and Petropoulos, George and Burger, Valentin and Seufert, Michael and Soursos, Sergios and Stiller, Burkhard}, booktitle = {40th Annual IEEE Conference on Local Computer Networks (LCN)}, keywords = {smartenit}, month = 10, title = {Augmenting Home Routers for Socially-Aware Traffic Management}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-518 %A Lareida, Andri %A Petropoulos, George %A Burger, Valentin %A Seufert, Michael %A Soursos, Sergios %A Stiller, Burkhard %B 40th Annual IEEE Conference on Local Computer Networks (LCN) %C Clearwater Beach, FL, USA %D 2015 %T Augmenting Home Routers for Socially-Aware Traffic Management %X Mobile users' Quality-of-Experience (QoE) is degrading as network usage increases while Internet Service Providers (ISP) face increased inter-domain traffic. This paper presents a network traffic management mechanism, named RB-HORST, addressing these inefficiencies. RB-HORST exploits home routers by using them as caches and forming an overlay network between them to transfer content. To shift traffic from peak hours, RB-HORST employs predictions based on social network properties and based on similarity in the overlay network. To further improve user QoE, home routers allow trusted mobile devices to offload their mobile connection to the local WiFi. Simulation results show that an overlay is imperative for the success of the proposed caching mechanism. Especially ISPs with a large number of customers can benefit if only every thousandth user shares its router, reducing inter-domain traffic by half and superseding an ISP operated cache. The presented implementation proves that the concept is technically feasible and can be deployed and run on constrained devices.
• Modeling Crowdsourcing Platforms to Enable Workforce Dimensioning. Schwartz, Christian; Borchert, Kathrin; Hirth, Matthias; Tran-Gia, Phuoc. In International Telecommunication Networks and Applications Conference. Sydney, Australia, 2015.
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  Crowdsourcing platforms provide an easy and scalable access to human workforce that can, e.g., provide subjective judgements, tagging information, or even generate knowledge. In conjunction with machine clouds offering scalable access to computing resources, these human cloud provider offer numerous possibilities for creating new applications which would not have been possible a few years ago. However, in order to build sustainable services on top of this inter-cloud environment, scalability considerations have to be made. While cloud computing systems are already well studied in terms of dimensioning of the hardware resources, there still exists little work on the appropriate scaling of crowdsourcing platforms. This is especially challenging, as the complex interaction between all involved stakeholders, platform providers, workers and employers have to be considered. The contribution of this work is threefold. First we develop a model for common crowdsourcing platforms and implement the model using a simulative approach, which is validated with a comparison to an analytic M[X]/M/c − ∞ system. In a second step we evaluate inter-arrival times as well as campaign size distributions based on a dataset of a large commercial crowdsourcing platform to derive realistic model parameters and illustrate the differences to the analytic approximation. Finally, we perform a parameter study using the simulation model to derive guidelines for dimensioning crowdsourcing platforms, while considering relevant parameters for the involved stakeholders, i.e., the delay before work on a task begins and the work load of the workers.

  @inproceedings{info3-inproceedings-2015-529, abstract = {Crowdsourcing platforms provide an easy and scalable access to human workforce that can, e.g., provide subjective judgements, tagging information, or even generate knowledge. In conjunction with machine clouds offering scalable access to computing resources, these human cloud provider offer numerous possibilities for creating new applications which would not have been possible a few years ago. However, in order to build sustainable services on top of this inter-cloud environment, scalability considerations have to be made. While cloud computing systems are already well studied in terms of dimensioning of the hardware resources, there still exists little work on the appropriate scaling of crowdsourcing platforms. This is especially challenging, as the complex interaction between all involved stakeholders, platform providers, workers and employers have to be considered. The contribution of this work is threefold. First we develop a model for common crowdsourcing platforms and implement the model using a simulative approach, which is validated with a comparison to an analytic M[X]/M/c − ∞ system. In a second step we evaluate inter-arrival times as well as campaign size distributions based on a dataset of a large commercial crowdsourcing platform to derive realistic model parameters and illustrate the differences to the analytic approximation. Finally, we perform a parameter study using the simulation model to derive guidelines for dimensioning crowdsourcing platforms, while considering relevant parameters for the involved stakeholders, i.e., the delay before work on a task begins and the work load of the workers.}, address = {Sydney, Australia}, author = {Schwartz, Christian and Borchert, Kathrin and Hirth, Matthias and Tran-Gia, Phuoc}, booktitle = {International Telecommunication Networks and Applications Conference}, keywords = {crowdsourcing-design}, month = 11, title = {Modeling Crowdsourcing Platforms to Enable Workforce Dimensioning}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-529 %A Schwartz, Christian %A Borchert, Kathrin %A Hirth, Matthias %A Tran-Gia, Phuoc %B International Telecommunication Networks and Applications Conference %C Sydney, Australia %D 2015 %T Modeling Crowdsourcing Platforms to Enable Workforce Dimensioning %X Crowdsourcing platforms provide an easy and scalable access to human workforce that can, e.g., provide subjective judgements, tagging information, or even generate knowledge. In conjunction with machine clouds offering scalable access to computing resources, these human cloud provider offer numerous possibilities for creating new applications which would not have been possible a few years ago. However, in order to build sustainable services on top of this inter-cloud environment, scalability considerations have to be made. While cloud computing systems are already well studied in terms of dimensioning of the hardware resources, there still exists little work on the appropriate scaling of crowdsourcing platforms. This is especially challenging, as the complex interaction between all involved stakeholders, platform providers, workers and employers have to be considered. The contribution of this work is threefold. First we develop a model for common crowdsourcing platforms and implement the model using a simulative approach, which is validated with a comparison to an analytic M[X]/M/c − ∞ system. In a second step we evaluate inter-arrival times as well as campaign size distributions based on a dataset of a large commercial crowdsourcing platform to derive realistic model parameters and illustrate the differences to the analytic approximation. Finally, we perform a parameter study using the simulation model to derive guidelines for dimensioning crowdsourcing platforms, while considering relevant parameters for the involved stakeholders, i.e., the delay before work on a task begins and the work load of the workers.
• Demands on Task Recommendation in Crowdsourcing Platforms - The Worker’s Perspective. Schnitzer, Steffen; Rensing, Christoph; Schmidt, Sebastian; Borchert, Kathrin; Hirth, Matthias; Tran-Gia, Phuoc. In CrowdRec Workshop. Vienna, Austria, 2015.
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  Crowdsourcing platforms support the assignment of jobs to help requesters in their project completion and allow workers to earn money. Most crowdsourcing platforms apply simple schemes in order to filter the tasks a worker can choose from or rely on the workers’ search capabilities. Using genuine task recommendation within such crowdsourcing plat- forms opens promising opportunities. Such recommendation schemes will only be effective if the workers are confident that they are used towards their own good. In order to gain insights on what kind of recommendations the workers would expect and accept, this work provides an empirical study about the demands of the workers.

  @inproceedings{info3-inproceedings-2015-525, abstract = {Crowdsourcing platforms support the assignment of jobs to help requesters in their project completion and allow workers to earn money. Most crowdsourcing platforms apply simple schemes in order to filter the tasks a worker can choose from or rely on the workers’ search capabilities. Using genuine task recommendation within such crowdsourcing plat- forms opens promising opportunities. Such recommendation schemes will only be effective if the workers are confident that they are used towards their own good. In order to gain insights on what kind of recommendations the workers would expect and accept, this work provides an empirical study about the demands of the workers.}, address = {Vienna, Austria}, author = {Schnitzer, Steffen and Rensing, Christoph and Schmidt, Sebastian and Borchert, Kathrin and Hirth, Matthias and Tran-Gia, Phuoc}, booktitle = {CrowdRec Workshop}, keywords = {crowdsourcing-design}, month = {09}, title = {Demands on Task Recommendation in Crowdsourcing Platforms - The Worker’s Perspective}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-525 %A Schnitzer, Steffen %A Rensing, Christoph %A Schmidt, Sebastian %A Borchert, Kathrin %A Hirth, Matthias %A Tran-Gia, Phuoc %B CrowdRec Workshop %C Vienna, Austria %D 2015 %T Demands on Task Recommendation in Crowdsourcing Platforms - The Worker’s Perspective %X Crowdsourcing platforms support the assignment of jobs to help requesters in their project completion and allow workers to earn money. Most crowdsourcing platforms apply simple schemes in order to filter the tasks a worker can choose from or rely on the workers’ search capabilities. Using genuine task recommendation within such crowdsourcing plat- forms opens promising opportunities. Such recommendation schemes will only be effective if the workers are confident that they are used towards their own good. In order to gain insights on what kind of recommendations the workers would expect and accept, this work provides an empirical study about the demands of the workers.
• Specialized Heuristics for the Controller Placement Problem in Large Scale SDN Networks. Lange, Stanislav; Gebert, Steffen; Spoerhase, Joachim; Rygielski, Piotr; Zinner, Thomas; Kounev, Samuel; Tran-Gia, Phuoc. In International Teletraffic Congress (ITC 27). Ghent, Belgium, 2015.
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  The Software Defined Networking~(SDN) concept introduces a paradigm shift in the networking world towards an externalized control plane which is logically centralized. When designing an SDN-based WAN architecture, it is of vital importance to find a feasible solution to the controller placement problem, i.e., to decide where to position a limited amount of resources within the network. In addition to time-independent constraints regarding aspects like scalability, resilience, and control plane communication delays, dynamically changing network conditions like traffic patterns or bandwidth demands need to be considered as well. Consequently, such dynamic environments call for a regular and fast recalculation of placements in order to adapt to the current situation in a timely manner. While an exhaustive evaluation of all possible solutions can be performed within a practically feasible time frame for small and medium-sized networks, such an approach is out of scope for large problem instances which have significantly higher time and memory requirements. Therefore, this work investigates a specialized heuristic, which takes into account a particular set of optimization objectives and returns solutions representing the possible trade-offs between them. Due to its low computation time and acceptable margin of error, this heuristic can be employed by automatic decision systems operating in dynamic environments.

  @inproceedings{info3-inproceedings-2015-519, abstract = {The Software Defined Networking (SDN) concept introduces a paradigm shift in the networking world towards an externalized control plane which is logically centralized. When designing an SDN-based WAN architecture, it is of vital importance to find a feasible solution to the controller placement problem, i.e., to decide where to position a limited amount of resources within the network. In addition to time-independent constraints regarding aspects like scalability, resilience, and control plane communication delays, dynamically changing network conditions like traffic patterns or bandwidth demands need to be considered as well. Consequently, such dynamic environments call for a regular and fast recalculation of placements in order to adapt to the current situation in a timely manner. While an exhaustive evaluation of all possible solutions can be performed within a practically feasible time frame for small and medium-sized networks, such an approach is out of scope for large problem instances which have significantly higher time and memory requirements. Therefore, this work investigates a specialized heuristic, which takes into account a particular set of optimization objectives and returns solutions representing the possible trade-offs between them. Due to its low computation time and acceptable margin of error, this heuristic can be employed by automatic decision systems operating in dynamic environments.}, address = {Ghent, Belgium}, author = {Lange, Stanislav and Gebert, Steffen and Spoerhase, Joachim and Rygielski, Piotr and Zinner, Thomas and Kounev, Samuel and Tran-Gia, Phuoc}, booktitle = {International Teletraffic Congress (ITC 27)}, keywords = {poco}, month = {09}, title = {Specialized Heuristics for the Controller Placement Problem in Large Scale SDN Networks}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-519 %A Lange, Stanislav %A Gebert, Steffen %A Spoerhase, Joachim %A Rygielski, Piotr %A Zinner, Thomas %A Kounev, Samuel %A Tran-Gia, Phuoc %B International Teletraffic Congress (ITC 27) %C Ghent, Belgium %D 2015 %T Specialized Heuristics for the Controller Placement Problem in Large Scale SDN Networks %X The Software Defined Networking~(SDN) concept introduces a paradigm shift in the networking world towards an externalized control plane which is logically centralized. When designing an SDN-based WAN architecture, it is of vital importance to find a feasible solution to the controller placement problem, i.e., to decide where to position a limited amount of resources within the network. In addition to time-independent constraints regarding aspects like scalability, resilience, and control plane communication delays, dynamically changing network conditions like traffic patterns or bandwidth demands need to be considered as well. Consequently, such dynamic environments call for a regular and fast recalculation of placements in order to adapt to the current situation in a timely manner. While an exhaustive evaluation of all possible solutions can be performed within a practically feasible time frame for small and medium-sized networks, such an approach is out of scope for large problem instances which have significantly higher time and memory requirements. Therefore, this work investigates a specialized heuristic, which takes into account a particular set of optimization objectives and returns solutions representing the possible trade-offs between them. Due to its low computation time and acceptable margin of error, this heuristic can be employed by automatic decision systems operating in dynamic environments.
• TableVisor: An Emulation Layer for Multi-Table OpenFlow Switches. Gebert, Steffen; Jarschel, Michael; Herrnleben, Stefan; Zinner, Thomas; Tran-Gia, Phuoc. In 4th European Workshop on Software Defined Networks (EWSDN). Bilbao, Spain, 2015.
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  This demonstration introduces TableVisor, which acts as a proxy layer between an OpenFlow controller and switches. Multiple hardware switches connect to TableVisor before it establishes a connection with the OpenFlow controller instance. During connection establishment, TableVisor advertises in the answer to the controller's features-request that this switch comprises a certain number of tables, which actually reflects the number of connected switches. All communication between controller and switch is passed through the proxy layer. Depending on the type of message, it will be answered directly by TableVisor (hello, features-reply), modified in such a way that particular fields are rewritten (packet-in, flow-mod), or a response merging data from multiple switches will be returned (flow-stats). The demonstration shows TableVisor in a MPLS use case using multiple switches, which is motivated by a mobile network scenario.

  @inproceedings{info3-inproceedings-2015-527, abstract = {This demonstration introduces TableVisor, which acts as a proxy layer between an OpenFlow controller and switches. Multiple hardware switches connect to TableVisor before it establishes a connection with the OpenFlow controller instance. During connection establishment, TableVisor advertises in the answer to the controller's features-request that this switch comprises a certain number of tables, which actually reflects the number of connected switches. All communication between controller and switch is passed through the proxy layer. Depending on the type of message, it will be answered directly by TableVisor (hello, features-reply), modified in such a way that particular fields are rewritten (packet-in, flow-mod), or a response merging data from multiple switches will be returned (flow-stats). The demonstration shows TableVisor in a MPLS use case using multiple switches, which is motivated by a mobile network scenario.}, address = {Bilbao, Spain}, author = {Gebert, Steffen and Jarschel, Michael and Herrnleben, Stefan and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {4th European Workshop on Software Defined Networks (EWSDN)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {TableVisor: An Emulation Layer for Multi-Table OpenFlow Switches}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-527 %A Gebert, Steffen %A Jarschel, Michael %A Herrnleben, Stefan %A Zinner, Thomas %A Tran-Gia, Phuoc %B 4th European Workshop on Software Defined Networks (EWSDN) %C Bilbao, Spain %D 2015 %T TableVisor: An Emulation Layer for Multi-Table OpenFlow Switches %X This demonstration introduces TableVisor, which acts as a proxy layer between an OpenFlow controller and switches. Multiple hardware switches connect to TableVisor before it establishes a connection with the OpenFlow controller instance. During connection establishment, TableVisor advertises in the answer to the controller's features-request that this switch comprises a certain number of tables, which actually reflects the number of connected switches. All communication between controller and switch is passed through the proxy layer. Depending on the type of message, it will be answered directly by TableVisor (hello, features-reply), modified in such a way that particular fields are rewritten (packet-in, flow-mod), or a response merging data from multiple switches will be returned (flow-stats). The demonstration shows TableVisor in a MPLS use case using multiple switches, which is motivated by a mobile network scenario.
• Analysis of Group-based Communication in WhatsApp. Seufert, Michael; Schwind, Anika; Hoßfeld, Tobias; Tran-Gia, Phuoc. In 7th EAI International Conference on Mobile Networks and Management (MONAMI). Santander, Spain, 2015.
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  This work investigates group-based communication in WhatsApp based on a survey and the analysis of messaging logs. The characteristics of WhatsApp group chats in terms of usage and topics are outlined. We present a classification based on the topic of the group and classify anonymized messaging logs based on message statistics. Finally, we model WhatsApp group communication with a semi-Markov process, which can be used to generate network traffic similar to real messaging logs.

  @inproceedings{info3-inproceedings-2015-523, abstract = {This work investigates group-based communication in WhatsApp based on a survey and the analysis of messaging logs. The characteristics of WhatsApp group chats in terms of usage and topics are outlined. We present a classification based on the topic of the group and classify anonymized messaging logs based on message statistics. Finally, we model WhatsApp group communication with a semi-Markov process, which can be used to generate network traffic similar to real messaging logs.}, address = {Santander, Spain}, author = {Seufert, Michael and Schwind, Anika and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {7th EAI International Conference on Mobile Networks and Management (MONAMI)}, keywords = {smartenit}, month = {09}, title = {Analysis of Group-based Communication in WhatsApp}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-523 %A Seufert, Michael %A Schwind, Anika %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B 7th EAI International Conference on Mobile Networks and Management (MONAMI) %C Santander, Spain %D 2015 %T Analysis of Group-based Communication in WhatsApp %X This work investigates group-based communication in WhatsApp based on a survey and the analysis of messaging logs. The characteristics of WhatsApp group chats in terms of usage and topics are outlined. We present a classification based on the topic of the group and classify anonymized messaging logs based on message statistics. Finally, we model WhatsApp group communication with a semi-Markov process, which can be used to generate network traffic similar to real messaging logs.
• A Simulation Framework for Evaluating the QoS and QoE of TCP-based Streaming in an LTE Network. Metzger, Florian; Steindl, Christoph; Hoßfeld, Tobias. In 27th International Teletraffic Congress (ITC). Ghent, Belgium, 2015.
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  @inproceedings{info3-inproceedings-2015-29, address = {Ghent, Belgium}, author = {Metzger, Florian and Steindl, Christoph and Hoßfeld, Tobias}, booktitle = {27th International Teletraffic Congress (ITC)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {A Simulation Framework for Evaluating the QoS and QoE of TCP-based Streaming in an LTE Network}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-29 %A Metzger, Florian %A Steindl, Christoph %A Hoßfeld, Tobias %B 27th International Teletraffic Congress (ITC) %C Ghent, Belgium %D 2015 %T A Simulation Framework for Evaluating the QoS and QoE of TCP-based Streaming in an LTE Network
• Analyzing the Impact of Delay and Packet Loss on Google Docs. Dinh-Xuan, Lam; Schwartz, Christian; Hirth, Matthias; Wamser, Florian; Truong Thu, Huong. In 7th International Conference on Mobile Networks and Management. Santander, Spain, 2015.
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  Software as a Service allows end users to use complex soft- ware directly from their browsers, transferring heavy computation to servers in the cloud. One use of this paradigm is word processing, former a classic use cases of Thin-Client computing. Similar to Thin-Client systems, the network parameters are an important influence factor for the cloud application performance. In this paper, we study Google Docs as an example for online word processing tools. We consider a traditional single user scenario as well as a collaborative scenario with two users working on one document simultaneously. We identify multiple relevant sub-processes per scenario as performance metrics and use a testbed to automatically evaluate the performance of Google Docs under varying network parameters. The main contributions of the paper are (1) the quantification of the impact of network parameters such as delay and packet loss on application performance metrics for both scenarios and (2) linear regression models to derive the application performance for giving network parameters.

  @inproceedings{info3-inproceedings-2015-522, abstract = {Software as a Service allows end users to use complex soft- ware directly from their browsers, transferring heavy computation to servers in the cloud. One use of this paradigm is word processing, former a classic use cases of Thin-Client computing. Similar to Thin-Client systems, the network parameters are an important influence factor for the cloud application performance. In this paper, we study Google Docs as an example for online word processing tools. We consider a traditional single user scenario as well as a collaborative scenario with two users working on one document simultaneously. We identify multiple relevant sub-processes per scenario as performance metrics and use a testbed to automatically evaluate the performance of Google Docs under varying network parameters. The main contributions of the paper are (1) the quantification of the impact of network parameters such as delay and packet loss on application performance metrics for both scenarios and (2) linear regression models to derive the application performance for giving network parameters.}, address = {Santander, Spain}, author = {Dinh-Xuan, Lam and Schwartz, Christian and Hirth, Matthias and Wamser, Florian and Truong Thu, Huong}, booktitle = {7th International Conference on Mobile Networks and Management}, keywords = {can}, month = {09}, title = {Analyzing the Impact of Delay and Packet Loss on Google Docs}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-522 %A Dinh-Xuan, Lam %A Schwartz, Christian %A Hirth, Matthias %A Wamser, Florian %A Truong Thu, Huong %B 7th International Conference on Mobile Networks and Management %C Santander, Spain %D 2015 %T Analyzing the Impact of Delay and Packet Loss on Google Docs %X Software as a Service allows end users to use complex soft- ware directly from their browsers, transferring heavy computation to servers in the cloud. One use of this paradigm is word processing, former a classic use cases of Thin-Client computing. Similar to Thin-Client systems, the network parameters are an important influence factor for the cloud application performance. In this paper, we study Google Docs as an example for online word processing tools. We consider a traditional single user scenario as well as a collaborative scenario with two users working on one document simultaneously. We identify multiple relevant sub-processes per scenario as performance metrics and use a testbed to automatically evaluate the performance of Google Docs under varying network parameters. The main contributions of the paper are (1) the quantification of the impact of network parameters such as delay and packet loss on application performance metrics for both scenarios and (2) linear regression models to derive the application performance for giving network parameters.
• Energy Considerations for WiFi Offloading of Video Streaming. Burger, Valentin; Kaup, Fabian; Seufert, Michael; Wichtlhuber, Matthias; Hausheer, David; Tran-Gia, Phuoc. In 7th EAI International Conference on Mobile Networks and Management (MONAMI). Santander, Spain, 2015.
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  The load on cellular networks is constantly increasing. Especially video streaming applications, whose demands and requirements keep growing, put high loads on cellular networks. A solution to mitigate the cellular load in urban environments is offloading mobile connections to WiFi access points, which is followed by many providers recently. Because of the large number of mobile users and devices there is also a high potential to save energy by WiFi offloading. In this work, we develop a model to assess the energy consumption of mobile devices during video sessions. We evaluate the potential of WiFi offloading in an urban environment and the implications of offloading connections on energy consumption of mobile devices. Our results show that, although WiFi is more energy efficient than 3G and 4G for equal data rates, the energy consumption increases with the amount of connections offloaded to WiFi, due to poor data rates obtained for WiFi in the streets. This suggests further deployment of WiFi access points or WiFi sharing incentives to increase data rates for WiFi and energy efficiency of mobile access.

  @inproceedings{info3-inproceedings-2015-524, abstract = {The load on cellular networks is constantly increasing. Especially video streaming applications, whose demands and requirements keep growing, put high loads on cellular networks. A solution to mitigate the cellular load in urban environments is offloading mobile connections to WiFi access points, which is followed by many providers recently. Because of the large number of mobile users and devices there is also a high potential to save energy by WiFi offloading. In this work, we develop a model to assess the energy consumption of mobile devices during video sessions. We evaluate the potential of WiFi offloading in an urban environment and the implications of offloading connections on energy consumption of mobile devices. Our results show that, although WiFi is more energy efficient than 3G and 4G for equal data rates, the energy consumption increases with the amount of connections offloaded to WiFi, due to poor data rates obtained for WiFi in the streets. This suggests further deployment of WiFi access points or WiFi sharing incentives to increase data rates for WiFi and energy efficiency of mobile access.}, address = {Santander, Spain}, author = {Burger, Valentin and Kaup, Fabian and Seufert, Michael and Wichtlhuber, Matthias and Hausheer, David and Tran-Gia, Phuoc}, booktitle = {7th EAI International Conference on Mobile Networks and Management (MONAMI)}, keywords = {smartenit}, month = {09}, title = {Energy Considerations for WiFi Offloading of Video Streaming}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-524 %A Burger, Valentin %A Kaup, Fabian %A Seufert, Michael %A Wichtlhuber, Matthias %A Hausheer, David %A Tran-Gia, Phuoc %B 7th EAI International Conference on Mobile Networks and Management (MONAMI) %C Santander, Spain %D 2015 %T Energy Considerations for WiFi Offloading of Video Streaming %X The load on cellular networks is constantly increasing. Especially video streaming applications, whose demands and requirements keep growing, put high loads on cellular networks. A solution to mitigate the cellular load in urban environments is offloading mobile connections to WiFi access points, which is followed by many providers recently. Because of the large number of mobile users and devices there is also a high potential to save energy by WiFi offloading. In this work, we develop a model to assess the energy consumption of mobile devices during video sessions. We evaluate the potential of WiFi offloading in an urban environment and the implications of offloading connections on energy consumption of mobile devices. Our results show that, although WiFi is more energy efficient than 3G and 4G for equal data rates, the energy consumption increases with the amount of connections offloaded to WiFi, due to poor data rates obtained for WiFi in the streets. This suggests further deployment of WiFi access points or WiFi sharing incentives to increase data rates for WiFi and energy efficiency of mobile access.
• Text Categorization for Deriving the Application Quality in Enterprises using Ticketing Systems. Zinner, Thomas; Lemmerich, Florian; Schwarzmann, Susanna; Hirth, Matthias; Karg, Peter; Hotho, Andreas. In 17th International Conference on Big Data Analytics and Knowledge Discovery (DaWaK 2015). Valencia, Spain, 2015.
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  Today’s enterprise services and business applications are of- ten centralized in a small number of data centers. Employees located at branches and side offices access the computing infrastructure via the internet using thin client architectures. The task to provide a good application quality to the employers using a multitude of different applications and access networks has thus become complex. Enterprises have to be able to identify resource bottlenecks and applications with a poor performance quickly to take appropriate countermeasures and enable a good application quality for their employees. Ticketing systems within an enterprise use large databases for collecting complaints and problems of the users over a long period of time and thus are an interesting starting point to identify performance problems. However, manual categorization of tickets comes with a high workload. In this paper, we analyze in a case study the applicability of supervised learning algorithms for the automatic identification of relevant tickets, i.e., tickets indicating problematic applications. In that regard, we evaluate different classification algorithms using 12,000 manually annotated tickets accumulated in July 2013 at the ticketing system of a nation- wide operating enterprise. In addition to traditional machine learning metrics, we also analyze the performance of the different classifiers on business-relevant metrics.

  @inproceedings{info3-inproceedings-2015-517, abstract = {Today’s enterprise services and business applications are of- ten centralized in a small number of data centers. Employees located at branches and side offices access the computing infrastructure via the internet using thin client architectures. The task to provide a good application quality to the employers using a multitude of different applications and access networks has thus become complex. Enterprises have to be able to identify resource bottlenecks and applications with a poor performance quickly to take appropriate countermeasures and enable a good application quality for their employees. Ticketing systems within an enterprise use large databases for collecting complaints and problems of the users over a long period of time and thus are an interesting starting point to identify performance problems. However, manual categorization of tickets comes with a high workload. In this paper, we analyze in a case study the applicability of supervised learning algorithms for the automatic identification of relevant tickets, i.e., tickets indicating problematic applications. In that regard, we evaluate different classification algorithms using 12,000 manually annotated tickets accumulated in July 2013 at the ticketing system of a nation- wide operating enterprise. In addition to traditional machine learning metrics, we also analyze the performance of the different classifiers on business-relevant metrics.}, address = {Valencia, Spain}, author = {Zinner, Thomas and Lemmerich, Florian and Schwarzmann, Susanna and Hirth, Matthias and Karg, Peter and Hotho, Andreas}, booktitle = {17th International Conference on Big Data Analytics and Knowledge Discovery (DaWaK 2015)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Text Categorization for Deriving the Application Quality in Enterprises using Ticketing Systems}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-517 %A Zinner, Thomas %A Lemmerich, Florian %A Schwarzmann, Susanna %A Hirth, Matthias %A Karg, Peter %A Hotho, Andreas %B 17th International Conference on Big Data Analytics and Knowledge Discovery (DaWaK 2015) %C Valencia, Spain %D 2015 %T Text Categorization for Deriving the Application Quality in Enterprises using Ticketing Systems %X Today’s enterprise services and business applications are of- ten centralized in a small number of data centers. Employees located at branches and side offices access the computing infrastructure via the internet using thin client architectures. The task to provide a good application quality to the employers using a multitude of different applications and access networks has thus become complex. Enterprises have to be able to identify resource bottlenecks and applications with a poor performance quickly to take appropriate countermeasures and enable a good application quality for their employees. Ticketing systems within an enterprise use large databases for collecting complaints and problems of the users over a long period of time and thus are an interesting starting point to identify performance problems. However, manual categorization of tickets comes with a high workload. In this paper, we analyze in a case study the applicability of supervised learning algorithms for the automatic identification of relevant tickets, i.e., tickets indicating problematic applications. In that regard, we evaluate different classification algorithms using 12,000 manually annotated tickets accumulated in July 2013 at the ticketing system of a nation- wide operating enterprise. In addition to traditional machine learning metrics, we also analyze the performance of the different classifiers on business-relevant metrics.

• Crowdsourcing 2.0: Enhancing Execution Speed and Reliability of Web-based QoE Testing. Gardlo, Bruno; Egger, Sebastian; Seufert, Michael; Schatz, Raimund. In IEEE International Conference on Communications (ICC). Sydney, Australia, 2014.
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  Since its introduction a few years ago, the concept of 'Crowdsourcing' has been heralded as highly attractive alternative approach towards evaluating the Quality of Experience (QoE) of networked multimedia services. The main reason is that, in comparison to traditional laboratory-based subjective quality testing, crowd-based QoE assessment over the Internet promises to be not only much more cost-effective (no lab facilities required, less cost per subject) but also much faster in terms of shorter campaign setup and turnaround times. However, the reliability of remote test subjects and consequently, the trustworthiness of study results is still an issue that prevents the widespread adoption of crowd-based QoE testing. Various ideas for improving user rating reliability and test efficiency have been proposed, with the majority of them relying on a posteriori analysis of results. However, such methods introduce a major lag that significantly affects efficiency of campaign execution. In this paper we address these shortcomings by introducing in momento methods for crowdsourced video QoE assessment, which yield improvements of results reliability by the factor two and campaign execution efficiency by the factor ten. The proposed in momento methods are applicable to existing crowd-based QoE testing approaches and suitable for a variety of service scenarios.

  @inproceedings{info3-inproceedings-2014-488, abstract = {Since its introduction a few years ago, the concept of 'Crowdsourcing' has been heralded as highly attractive alternative approach towards evaluating the Quality of Experience (QoE) of networked multimedia services. The main reason is that, in comparison to traditional laboratory-based subjective quality testing, crowd-based QoE assessment over the Internet promises to be not only much more cost-effective (no lab facilities required, less cost per subject) but also much faster in terms of shorter campaign setup and turnaround times. However, the reliability of remote test subjects and consequently, the trustworthiness of study results is still an issue that prevents the widespread adoption of crowd-based QoE testing. Various ideas for improving user rating reliability and test efficiency have been proposed, with the majority of them relying on a posteriori analysis of results. However, such methods introduce a major lag that significantly affects efficiency of campaign execution. In this paper we address these shortcomings by introducing in momento methods for crowdsourced video QoE assessment, which yield improvements of results reliability by the factor two and campaign execution efficiency by the factor ten. The proposed in momento methods are applicable to existing crowd-based QoE testing approaches and suitable for a variety of service scenarios.}, address = {Sydney, Australia}, author = {Gardlo, Bruno and Egger, Sebastian and Seufert, Michael and Schatz, Raimund}, booktitle = {IEEE International Conference on Communications (ICC)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Crowdsourcing 2.0: Enhancing Execution Speed and Reliability of Web-based QoE Testing}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-488 %A Gardlo, Bruno %A Egger, Sebastian %A Seufert, Michael %A Schatz, Raimund %B IEEE International Conference on Communications (ICC) %C Sydney, Australia %D 2014 %T Crowdsourcing 2.0: Enhancing Execution Speed and Reliability of Web-based QoE Testing %X Since its introduction a few years ago, the concept of 'Crowdsourcing' has been heralded as highly attractive alternative approach towards evaluating the Quality of Experience (QoE) of networked multimedia services. The main reason is that, in comparison to traditional laboratory-based subjective quality testing, crowd-based QoE assessment over the Internet promises to be not only much more cost-effective (no lab facilities required, less cost per subject) but also much faster in terms of shorter campaign setup and turnaround times. However, the reliability of remote test subjects and consequently, the trustworthiness of study results is still an issue that prevents the widespread adoption of crowd-based QoE testing. Various ideas for improving user rating reliability and test efficiency have been proposed, with the majority of them relying on a posteriori analysis of results. However, such methods introduce a major lag that significantly affects efficiency of campaign execution. In this paper we address these shortcomings by introducing in momento methods for crowdsourced video QoE assessment, which yield improvements of results reliability by the factor two and campaign execution efficiency by the factor ten. The proposed in momento methods are applicable to existing crowd-based QoE testing approaches and suitable for a variety of service scenarios.
• Including Energy Efficiency Aspects in Multi-Layer Optical Network Design. Gebert, Steffen; Hock, David; Hartmann, Matthias; Spoerhase, Joachim; Zinner, Thomas; Tran-Gia, Phuoc. In 5th International Conference on Communications and Electronics (ICCE 2014). Da Nang, Vietnam, 2014.
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  This paper investigates the influence of the network planning process on a higher energy-awareness of optical multi-layer core networks. In particular, we propose to remove redundant links in the network, and to route corresponding network traffic on other links. Based on the reduced network topology, we compute the required network equipment for realistic traffic demands using a network planning tool. Due to the lack of an accurate model for operational expenditures and energy consumption, we choose the link length as cost function. We show the applicability of our idea and demonstrate the energy saving potential using realistic network topologies.

  @inproceedings{info3-inproceedings-2014-492, abstract = {This paper investigates the influence of the network planning process on a higher energy-awareness of optical multi-layer core networks. In particular, we propose to remove redundant links in the network, and to route corresponding network traffic on other links. Based on the reduced network topology, we compute the required network equipment for realistic traffic demands using a network planning tool. Due to the lack of an accurate model for operational expenditures and energy consumption, we choose the link length as cost function. We show the applicability of our idea and demonstrate the energy saving potential using realistic network topologies.}, address = {Da Nang, Vietnam}, author = {Gebert, Steffen and Hock, David and Hartmann, Matthias and Spoerhase, Joachim and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {5th International Conference on Communications and Electronics (ICCE 2014)}, keywords = {saser-siegfried}, month = {07}, title = {Including Energy Efficiency Aspects in Multi-Layer Optical Network Design}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-492 %A Gebert, Steffen %A Hock, David %A Hartmann, Matthias %A Spoerhase, Joachim %A Zinner, Thomas %A Tran-Gia, Phuoc %B 5th International Conference on Communications and Electronics (ICCE 2014) %C Da Nang, Vietnam %D 2014 %T Including Energy Efficiency Aspects in Multi-Layer Optical Network Design %X This paper investigates the influence of the network planning process on a higher energy-awareness of optical multi-layer core networks. In particular, we propose to remove redundant links in the network, and to route corresponding network traffic on other links. Based on the reduced network topology, we compute the required network equipment for realistic traffic demands using a network planning tool. Due to the lack of an accurate model for operational expenditures and energy consumption, we choose the link length as cost function. We show the applicability of our idea and demonstrate the energy saving potential using realistic network topologies.
• GTP-based Load Model and Virtualization Gain for a Mobile Network’s GGSN. Metzger, Florian; Schwartz, Christian; Hoßfeld, Tobias. In 5th International Conference on Communications and Electronics. Da Nang, Vietnam, 2014.
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  Multiple outages in major mobile networks have been reported in the recent past. In fixed and datacenter networks, such capacity problems are solved by scaling out, i.e. purchasing additional hardware. In mobile networks this is not easily possible as network components are usually sold as sealed middleboxes. With the advances in server performance and SDN it has been suggested to virtualize these boxes. This also opens up opportunities to dimension according to current load and save energy by switching off parts of the infrastructure. Such suggestions immediately raise the question on the cost of virtualization. To answer this question, we introduce models for both a traditional as well as a virtualized GGSN. In addition, we provide distributions for the load experienced at the GGSN based on network measurements. With this at hand, we study the influence of different dimensioning parameters on important performance metrics, with special consideration for the impact of provisioning new instances for the virtual GGSN.

  @inproceedings{info3-inproceedings-2014-497, abstract = {Multiple outages in major mobile networks have been reported in the recent past. In fixed and datacenter networks, such capacity problems are solved by scaling out, i.e. purchasing additional hardware. In mobile networks this is not easily possible as network components are usually sold as sealed middleboxes. With the advances in server performance and SDN it has been suggested to virtualize these boxes. This also opens up opportunities to dimension according to current load and save energy by switching off parts of the infrastructure. Such suggestions immediately raise the question on the cost of virtualization. To answer this question, we introduce models for both a traditional as well as a virtualized GGSN. In addition, we provide distributions for the load experienced at the GGSN based on network measurements. With this at hand, we study the influence of different dimensioning parameters on important performance metrics, with special consideration for the impact of provisioning new instances for the virtual GGSN.}, address = {Da Nang, Vietnam}, author = {Metzger, Florian and Schwartz, Christian and Hoßfeld, Tobias}, booktitle = {5th International Conference on Communications and Electronics}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {GTP-based Load Model and Virtualization Gain for a Mobile Network's GGSN}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-497 %A Metzger, Florian %A Schwartz, Christian %A Hoßfeld, Tobias %B 5th International Conference on Communications and Electronics %C Da Nang, Vietnam %D 2014 %T GTP-based Load Model and Virtualization Gain for a Mobile Network's GGSN %X Multiple outages in major mobile networks have been reported in the recent past. In fixed and datacenter networks, such capacity problems are solved by scaling out, i.e. purchasing additional hardware. In mobile networks this is not easily possible as network components are usually sold as sealed middleboxes. With the advances in server performance and SDN it has been suggested to virtualize these boxes. This also opens up opportunities to dimension according to current load and save energy by switching off parts of the infrastructure. Such suggestions immediately raise the question on the cost of virtualization. To answer this question, we introduce models for both a traditional as well as a virtualized GGSN. In addition, we provide distributions for the load experienced at the GGSN based on network measurements. With this at hand, we study the influence of different dimensioning parameters on important performance metrics, with special consideration for the impact of provisioning new instances for the virtual GGSN.
• Crowdsourcing: From Theory to Practice and Long-Term Perspectives. Hoßfeld, Tobias; Tran-Gia, Phuoc; Vukovic, Maja. In Dagstuhl Reports. 2014.
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  @inproceedings{info3-inproceedings-2014-21, author = {Hoßfeld, Tobias and Tran-Gia, Phuoc and Vukovic, Maja}, booktitle = {Dagstuhl Reports}, keywords = {sys:hidden:inproceedings}, title = {Crowdsourcing: From Theory to Practice and Long-Term Perspectives}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-21 %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %A Vukovic, Maja %B Dagstuhl Reports %D 2014 %T Crowdsourcing: From Theory to Practice and Long-Term Perspectives
• Dynamic Application-Aware Resource Management Using Software-Defined Networking: Implementation Prospects and Challenges. Zinner, Thomas; Jarschel, Michael; Blenk, Andreas; Wamser, Florian; Kellerer, Wolfgang. In IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan). Krakow, Poland, 2014.
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  Today’s Internet does not provide an exchange of information between applications and networks, which may result in poor application performance. Concepts such as applicationaware networking or network-aware application programming try to overcome these limitations. The introduction of Software- Defined Networking (SDN) opens a path towards the realization of an enhanced interaction between networks and applications. Hence, a more dynamic and demand-based allocation of network resources to heterogeneous applications can be realized. The implementation of the resource management action, however, may have an impact on the data transport and application quality. This paper summarizes resource management mechanisms provided by current SDN approaches based on OpenFlow and exemplary evaluates implementation prospects and challenges.

  @inproceedings{info3-inproceedings-2014-490, abstract = {Today’s Internet does not provide an exchange of information between applications and networks, which may result in poor application performance. Concepts such as applicationaware networking or network-aware application programming try to overcome these limitations. The introduction of Software- Defined Networking (SDN) opens a path towards the realization of an enhanced interaction between networks and applications. Hence, a more dynamic and demand-based allocation of network resources to heterogeneous applications can be realized. The implementation of the resource management action, however, may have an impact on the data transport and application quality. This paper summarizes resource management mechanisms provided by current SDN approaches based on OpenFlow and exemplary evaluates implementation prospects and challenges.}, address = {Krakow, Poland}, author = {Zinner, Thomas and Jarschel, Michael and Blenk, Andreas and Wamser, Florian and Kellerer, Wolfgang}, booktitle = {IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Dynamic Application-Aware Resource Management Using Software-Defined Networking: Implementation Prospects and Challenges}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-490 %A Zinner, Thomas %A Jarschel, Michael %A Blenk, Andreas %A Wamser, Florian %A Kellerer, Wolfgang %B IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan) %C Krakow, Poland %D 2014 %T Dynamic Application-Aware Resource Management Using Software-Defined Networking: Implementation Prospects and Challenges %X Today’s Internet does not provide an exchange of information between applications and networks, which may result in poor application performance. Concepts such as applicationaware networking or network-aware application programming try to overcome these limitations. The introduction of Software- Defined Networking (SDN) opens a path towards the realization of an enhanced interaction between networks and applications. Hence, a more dynamic and demand-based allocation of network resources to heterogeneous applications can be realized. The implementation of the resource management action, however, may have an impact on the data transport and application quality. This paper summarizes resource management mechanisms provided by current SDN approaches based on OpenFlow and exemplary evaluates implementation prospects and challenges.
• Increasing the Coverage of Vantage Points in Distributed Active Network Measurements by Crowdsourcing. Burger, Valentin; Hirth, Matthias; Schwartz, Christian; Hoßfeld, Tobias. In Measurement, Modelling and Evaluation of Computing Systems (MMB 2014). Bamberg, Germany, 2014.
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  Internet video constitutes more than half of all consumer traffic. Most of the video traffic is delivered by content delivery networks (CDNs). The huge amount of traffic from video CDNs poses problems to access providers. To understand and monitor the impact of video traffic on access networks and the topology of CDNs, distributed active measurements are needed. Recently used measurement platforms are mainly hosted in National Research and Education Networks (NRENs). However, the view of these platforms on the CDN is very limited, since the coverage of NRENs is low in developing countries. Furthermore campus networks do not reflect the characteristics of end user access networks. We propose to use crowdsourcing to increase the coverage of vantage points in distributed active network measurements. In this study, we compare measurements of a global CDN conducted in PlanetLab with measurements assigned to workers of a crowdsourcing platform. Therewith, the coverage of vantage points and the sampled part of the global video CDN are analyzed. Our results show that the capability of PlanetLab to measure global CDNs is rather low, since the vast majority of requests is directed to the US. By using the crowdsourcing platform we obtain a diverse set of vantage points that reveals more than twice as many autonomous systems deploying video servers.

  @inproceedings{info3-inproceedings-2014-486, abstract = {Internet video constitutes more than half of all consumer traffic. Most of the video traffic is delivered by content delivery networks (CDNs). The huge amount of traffic from video CDNs poses problems to access providers. To understand and monitor the impact of video traffic on access networks and the topology of CDNs, distributed active measurements are needed. Recently used measurement platforms are mainly hosted in National Research and Education Networks (NRENs). However, the view of these platforms on the CDN is very limited, since the coverage of NRENs is low in developing countries. Furthermore campus networks do not reflect the characteristics of end user access networks. We propose to use crowdsourcing to increase the coverage of vantage points in distributed active network measurements. In this study, we compare measurements of a global CDN conducted in PlanetLab with measurements assigned to workers of a crowdsourcing platform. Therewith, the coverage of vantage points and the sampled part of the global video CDN are analyzed. Our results show that the capability of PlanetLab to measure global CDNs is rather low, since the vast majority of requests is directed to the US. By using the crowdsourcing platform we obtain a diverse set of vantage points that reveals more than twice as many autonomous systems deploying video servers.}, address = {Bamberg, Germany}, author = {Burger, Valentin and Hirth, Matthias and Schwartz, Christian and Hoßfeld, Tobias}, booktitle = {Measurement, Modelling and Evaluation of Computing Systems (MMB 2014)}, keywords = {smartenit}, month = {03}, title = {Increasing the Coverage of Vantage Points in Distributed Active Network Measurements by Crowdsourcing}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-486 %A Burger, Valentin %A Hirth, Matthias %A Schwartz, Christian %A Hoßfeld, Tobias %B Measurement, Modelling and Evaluation of Computing Systems (MMB 2014) %C Bamberg, Germany %D 2014 %T Increasing the Coverage of Vantage Points in Distributed Active Network Measurements by Crowdsourcing %X Internet video constitutes more than half of all consumer traffic. Most of the video traffic is delivered by content delivery networks (CDNs). The huge amount of traffic from video CDNs poses problems to access providers. To understand and monitor the impact of video traffic on access networks and the topology of CDNs, distributed active measurements are needed. Recently used measurement platforms are mainly hosted in National Research and Education Networks (NRENs). However, the view of these platforms on the CDN is very limited, since the coverage of NRENs is low in developing countries. Furthermore campus networks do not reflect the characteristics of end user access networks. We propose to use crowdsourcing to increase the coverage of vantage points in distributed active network measurements. In this study, we compare measurements of a global CDN conducted in PlanetLab with measurements assigned to workers of a crowdsourcing platform. Therewith, the coverage of vantage points and the sampled part of the global video CDN are analyzed. Our results show that the capability of PlanetLab to measure global CDNs is rather low, since the vast majority of requests is directed to the US. By using the crowdsourcing platform we obtain a diverse set of vantage points that reveals more than twice as many autonomous systems deploying video servers.
• QoE of YouTube Video Streaming for Current Internet Transport Protocols. Hoßfeld, Tobias; Schatz, Raimund; Krieger, Udo. In Measurement, Modelling and Evaluation of Computing Systems (MMB 2014). Bamberg, Germany, 2014.
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  Video streaming currently dominates global Internet traffic and will be of even increasing importance in the future. In this paper we assess the impact of the underlying transport protocol on the user perceived quality for video streaming using YouTube as example. In particular, we investigate whether UDP or TCP fits better for Video-on-Demand delivery from the end user's perspective, when the video is transmitted over a bottleneck link. For UDP based streaming, the bottleneck link results in spatial and temporal video artifacts, decreasing the video quality. In contrast, in the case of TCP based streaming, the displayed content itself is not disturbed but playback suffers from stalling due to rebufferung. The results of subjective user studies for both scenarios are analyzed in order to assess the transport protocol influences on Quality of Experience of YouTube. To this end, application-level measurements are conducted for YouTube streaming over a network bottleneck in order to develop models for realistic stalling patterns. Furthermore, mapping functions are derived that accurately describe the relationship between network-level impairments and QoE for both protocols.

  @inproceedings{info3-inproceedings-2014-485, abstract = {Video streaming currently dominates global Internet traffic and will be of even increasing importance in the future. In this paper we assess the impact of the underlying transport protocol on the user perceived quality for video streaming using YouTube as example. In particular, we investigate whether UDP or TCP fits better for Video-on-Demand delivery from the end user's perspective, when the video is transmitted over a bottleneck link. For UDP based streaming, the bottleneck link results in spatial and temporal video artifacts, decreasing the video quality. In contrast, in the case of TCP based streaming, the displayed content itself is not disturbed but playback suffers from stalling due to rebufferung. The results of subjective user studies for both scenarios are analyzed in order to assess the transport protocol influences on Quality of Experience of YouTube. To this end, application-level measurements are conducted for YouTube streaming over a network bottleneck in order to develop models for realistic stalling patterns. Furthermore, mapping functions are derived that accurately describe the relationship between network-level impairments and QoE for both protocols.}, address = {Bamberg, Germany}, author = {Hoßfeld, Tobias and Schatz, Raimund and Krieger, Udo}, booktitle = {Measurement, Modelling and Evaluation of Computing Systems (MMB 2014)}, keywords = {demobenefit}, month = {03}, title = {QoE of YouTube Video Streaming for Current Internet Transport Protocols}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-485 %A Hoßfeld, Tobias %A Schatz, Raimund %A Krieger, Udo %B Measurement, Modelling and Evaluation of Computing Systems (MMB 2014) %C Bamberg, Germany %D 2014 %T QoE of YouTube Video Streaming for Current Internet Transport Protocols %X Video streaming currently dominates global Internet traffic and will be of even increasing importance in the future. In this paper we assess the impact of the underlying transport protocol on the user perceived quality for video streaming using YouTube as example. In particular, we investigate whether UDP or TCP fits better for Video-on-Demand delivery from the end user's perspective, when the video is transmitted over a bottleneck link. For UDP based streaming, the bottleneck link results in spatial and temporal video artifacts, decreasing the video quality. In contrast, in the case of TCP based streaming, the displayed content itself is not disturbed but playback suffers from stalling due to rebufferung. The results of subjective user studies for both scenarios are analyzed in order to assess the transport protocol influences on Quality of Experience of YouTube. To this end, application-level measurements are conducted for YouTube streaming over a network bottleneck in order to develop models for realistic stalling patterns. Furthermore, mapping functions are derived that accurately describe the relationship between network-level impairments and QoE for both protocols.
• Welcome message from the international workshop organizers FINGNet 2014. Hoßfeld, Tobias; Do, I; Jeong, HDJ; Chae, K; Nakao, Akihiro; Lim, J. In Proceedings-2014 8th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2014. 2014.
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  @inproceedings{info3-inproceedings-2014-22, author = {Hoßfeld, Tobias and Do, I and Jeong, HDJ and Chae, K and Nakao, Akihiro and Lim, J}, booktitle = {Proceedings-2014 8th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2014}, keywords = {sys:hidden:inproceedings}, title = {Welcome message from the international workshop organizers FINGNet 2014}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-22 %A Hoßfeld, Tobias %A Do, I %A Jeong, HDJ %A Chae, K %A Nakao, Akihiro %A Lim, J %B Proceedings-2014 8th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2014 %D 2014 %T Welcome message from the international workshop organizers FINGNet 2014
• Predicting Result Quality in Crowdsourcing Using Application Layer Monitoring. Hirth, Matthias; Scheuring, Sven; Hoßfeld, Tobias; Schwartz, Christian; Tran-Gia, Phuoc. In 5th International Conference on Communications and Electronics (ICCE 2014). Da Nang, Vietnam, 2014.
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  Crowdsourcing has become a valuable tool for many business applications requiring to meet a certain quality of the results generated by the workers. Therefore, several quality assurance mechanisms have been developed which are partly deployed in commercial crowdsourcing platforms. However, these mechanisms usually impose additional work overhead for the worker, e.g. by adding test questions, or increase the costs for the employer, e.g. by replicating the task for majority decisions. In this work, we analyze the applicability of implicit measurements to objectively estimate the quality of the workers' results. First efforts in this area have already been made by investigating the impact of the task completion time. We extend this research by deploying an application layer monitoring (ALM), which enables monitoring the workers' interactions with our task interface on a much more detailed level. Based on an exemplary use case, we discuss a possible implementation and demonstrate the potential of the approach by predicting the quality of the workers' submission based on our monitoring results. This ALM provides a new way to identify low quality work as well as difficulties in fulfilling the formulated tasks in the domain of Crowdsourcing.

  @inproceedings{info3-inproceedings-2014-494, abstract = {Crowdsourcing has become a valuable tool for many business applications requiring to meet a certain quality of the results generated by the workers. Therefore, several quality assurance mechanisms have been developed which are partly deployed in commercial crowdsourcing platforms. However, these mechanisms usually impose additional work overhead for the worker, e.g. by adding test questions, or increase the costs for the employer, e.g. by replicating the task for majority decisions. In this work, we analyze the applicability of implicit measurements to objectively estimate the quality of the workers' results. First efforts in this area have already been made by investigating the impact of the task completion time. We extend this research by deploying an application layer monitoring (ALM), which enables monitoring the workers' interactions with our task interface on a much more detailed level. Based on an exemplary use case, we discuss a possible implementation and demonstrate the potential of the approach by predicting the quality of the workers' submission based on our monitoring results. This ALM provides a new way to identify low quality work as well as difficulties in fulfilling the formulated tasks in the domain of Crowdsourcing.}, address = {Da Nang, Vietnam}, author = {Hirth, Matthias and Scheuring, Sven and Hoßfeld, Tobias and Schwartz, Christian and Tran-Gia, Phuoc}, booktitle = {5th International Conference on Communications and Electronics (ICCE 2014)}, keywords = {crowdsourcing-design}, month = {07}, title = {Predicting Result Quality in Crowdsourcing Using Application Layer Monitoring}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-494 %A Hirth, Matthias %A Scheuring, Sven %A Hoßfeld, Tobias %A Schwartz, Christian %A Tran-Gia, Phuoc %B 5th International Conference on Communications and Electronics (ICCE 2014) %C Da Nang, Vietnam %D 2014 %T Predicting Result Quality in Crowdsourcing Using Application Layer Monitoring %X Crowdsourcing has become a valuable tool for many business applications requiring to meet a certain quality of the results generated by the workers. Therefore, several quality assurance mechanisms have been developed which are partly deployed in commercial crowdsourcing platforms. However, these mechanisms usually impose additional work overhead for the worker, e.g. by adding test questions, or increase the costs for the employer, e.g. by replicating the task for majority decisions. In this work, we analyze the applicability of implicit measurements to objectively estimate the quality of the workers' results. First efforts in this area have already been made by investigating the impact of the task completion time. We extend this research by deploying an application layer monitoring (ALM), which enables monitoring the workers' interactions with our task interface on a much more detailed level. Based on an exemplary use case, we discuss a possible implementation and demonstrate the potential of the approach by predicting the quality of the workers' submission based on our monitoring results. This ALM provides a new way to identify low quality work as well as difficulties in fulfilling the formulated tasks in the domain of Crowdsourcing.
• Is affective crowdsourcing reliable?. Hupont, Isabelle; Lebreton, Pierre; Mäki, Toni; Skodras, Evangelos; Hirth, Matthias. In 5th International Conference on Communications and Electronics (ICCE 2014). Da Nang, Vietnam, 2014.
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  Affective content annotations are typically acquired from subjective manual assessments by experts in supervised laboratory tests. While well manageable, such campaigns are expensive, time-consuming and results may not be generalizable to larger audiences. Crowdsourcing constitutes a promising approach for quickly collecting data with wide demographic scope and reasonable costs. Undeniably, affective crowdsourcing is particularly challenging in the sense that it attempts to collect subjective perceptions from humans with different cultures, languages, knowledge background, etc. In this study we analyze the validity of well-known user affective scales in a crowdsourcing context by comparing results with the ones obtained in laboratory tests. Experimental results demonstrate that pictorial scales possess promising features for affective crowdsourcing.

  @inproceedings{info3-inproceedings-2014-493, abstract = {Affective content annotations are typically acquired from subjective manual assessments by experts in supervised laboratory tests. While well manageable, such campaigns are expensive, time-consuming and results may not be generalizable to larger audiences. Crowdsourcing constitutes a promising approach for quickly collecting data with wide demographic scope and reasonable costs. Undeniably, affective crowdsourcing is particularly challenging in the sense that it attempts to collect subjective perceptions from humans with different cultures, languages, knowledge background, etc. In this study we analyze the validity of well-known user affective scales in a crowdsourcing context by comparing results with the ones obtained in laboratory tests. Experimental results demonstrate that pictorial scales possess promising features for affective crowdsourcing.}, address = {Da Nang, Vietnam}, author = {Hupont, Isabelle and Lebreton, Pierre and Mäki, Toni and Skodras, Evangelos and Hirth, Matthias}, booktitle = {5th International Conference on Communications and Electronics (ICCE 2014)}, keywords = {crowdsourcing-design}, month = {07}, title = {Is affective crowdsourcing reliable?}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-493 %A Hupont, Isabelle %A Lebreton, Pierre %A Mäki, Toni %A Skodras, Evangelos %A Hirth, Matthias %B 5th International Conference on Communications and Electronics (ICCE 2014) %C Da Nang, Vietnam %D 2014 %T Is affective crowdsourcing reliable? %X Affective content annotations are typically acquired from subjective manual assessments by experts in supervised laboratory tests. While well manageable, such campaigns are expensive, time-consuming and results may not be generalizable to larger audiences. Crowdsourcing constitutes a promising approach for quickly collecting data with wide demographic scope and reasonable costs. Undeniably, affective crowdsourcing is particularly challenging in the sense that it attempts to collect subjective perceptions from humans with different cultures, languages, knowledge background, etc. In this study we analyze the validity of well-known user affective scales in a crowdsourcing context by comparing results with the ones obtained in laboratory tests. Experimental results demonstrate that pictorial scales possess promising features for affective crowdsourcing.
• OFCProbe: A Platform-Independent Tool for OpenFlow Controller Analysis. Jarschel, Michael; Metter, Christopher; Zinner, Thomas; Gebert, Steffen; Tran-Gia, Phuoc. In 5th IEEE International Conference on Communications and Electronics (IEEE ICCE 2014). Da Nang, Vietnam, 2014.
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  Controller performance and behavior are key to the operation of an SDN network. Therefore, choosing the right controller implementation and corresponding set of applications is essential. In order to facilitate this decision we previously introduced a tool for controller performance analysis called ”OFCBenchmark”. In this paper, we present ”OFCProbe” a platform-independent and extended re-design of our original approach. We describe the new architecture and explain the implemented features. Finally, we provide some sample results to illustrate the kind of investigations that can be performed using the tool.

  @inproceedings{info3-inproceedings-2014-496, abstract = {Controller performance and behavior are key to the operation of an SDN network. Therefore, choosing the right controller implementation and corresponding set of applications is essential. In order to facilitate this decision we previously introduced a tool for controller performance analysis called ”OFCBenchmark”. In this paper, we present ”OFCProbe” a platform-independent and extended re-design of our original approach. We describe the new architecture and explain the implemented features. Finally, we provide some sample results to illustrate the kind of investigations that can be performed using the tool.}, address = {Da Nang, Vietnam}, author = {Jarschel, Michael and Metter, Christopher and Zinner, Thomas and Gebert, Steffen and Tran-Gia, Phuoc}, booktitle = {5th IEEE International Conference on Communications and Electronics (IEEE ICCE 2014)}, keywords = {saser-siegfried}, month = {08}, title = {OFCProbe: A Platform-Independent Tool for OpenFlow Controller Analysis}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-496 %A Jarschel, Michael %A Metter, Christopher %A Zinner, Thomas %A Gebert, Steffen %A Tran-Gia, Phuoc %B 5th IEEE International Conference on Communications and Electronics (IEEE ICCE 2014) %C Da Nang, Vietnam %D 2014 %T OFCProbe: A Platform-Independent Tool for OpenFlow Controller Analysis %X Controller performance and behavior are key to the operation of an SDN network. Therefore, choosing the right controller implementation and corresponding set of applications is essential. In order to facilitate this decision we previously introduced a tool for controller performance analysis called ”OFCBenchmark”. In this paper, we present ”OFCProbe” a platform-independent and extended re-design of our original approach. We describe the new architecture and explain the implemented features. Finally, we provide some sample results to illustrate the kind of investigations that can be performed using the tool.
• An Overview of Application Traffic Management Approaches: Challenges and Potential Extensions. Papafili, Ioanna; Wajda, Krzysztof; Lapacz, Roman; Predieri, Alessandro; Bocek, Thomas; Seufert, Michael. In 8th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS). Birmingham, UK, 2014.
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  The Internet has seen a strong move to support overlay applications and services, which demand a coherent and integrated control in underlying heterogeneous networks in a scalable, resilient, and energy-efficient manner. To do so, a tighter integration of network management and overlay service functionality can lead to cross-layer optimization of operations and management, which is a promising approach and may offer a large business potential in operational perspectives for all players involved. Therefore, the objective of this paper is to present and discuss the impact of new paradigms such as cloud computing and software-defined networking which will play central role in the Future Internet, discuss major traffic trends and identify key challenges due to the adoption and operation of the new applications. Translating the key challenges to requirements for Future Internet traffic management mechanisms, the paper provides an extensive overview of existing mechanisms in literature, assesses them w.r.t. the aforementioned requirements, and qualitatively estimates the expected optimization potential and gain, as well as provides hint for their potential extension and exploitation within the challenging environment of the Future Internet.

  @inproceedings{info3-inproceedings-2014-489, abstract = {The Internet has seen a strong move to support overlay applications and services, which demand a coherent and integrated control in underlying heterogeneous networks in a scalable, resilient, and energy-efficient manner. To do so, a tighter integration of network management and overlay service functionality can lead to cross-layer optimization of operations and management, which is a promising approach and may offer a large business potential in operational perspectives for all players involved. Therefore, the objective of this paper is to present and discuss the impact of new paradigms such as cloud computing and software-defined networking which will play central role in the Future Internet, discuss major traffic trends and identify key challenges due to the adoption and operation of the new applications. Translating the key challenges to requirements for Future Internet traffic management mechanisms, the paper provides an extensive overview of existing mechanisms in literature, assesses them w.r.t. the aforementioned requirements, and qualitatively estimates the expected optimization potential and gain, as well as provides hint for their potential extension and exploitation within the challenging environment of the Future Internet.}, address = {Birmingham, UK}, author = {Papafili, Ioanna and Wajda, Krzysztof and Lapacz, Roman and Predieri, Alessandro and Bocek, Thomas and Seufert, Michael}, booktitle = {8th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS)}, keywords = {smartenit}, month = {07}, title = {An Overview of Application Traffic Management Approaches: Challenges and Potential Extensions}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-489 %A Papafili, Ioanna %A Wajda, Krzysztof %A Lapacz, Roman %A Predieri, Alessandro %A Bocek, Thomas %A Seufert, Michael %B 8th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS) %C Birmingham, UK %D 2014 %T An Overview of Application Traffic Management Approaches: Challenges and Potential Extensions %X The Internet has seen a strong move to support overlay applications and services, which demand a coherent and integrated control in underlying heterogeneous networks in a scalable, resilient, and energy-efficient manner. To do so, a tighter integration of network management and overlay service functionality can lead to cross-layer optimization of operations and management, which is a promising approach and may offer a large business potential in operational perspectives for all players involved. Therefore, the objective of this paper is to present and discuss the impact of new paradigms such as cloud computing and software-defined networking which will play central role in the Future Internet, discuss major traffic trends and identify key challenges due to the adoption and operation of the new applications. Translating the key challenges to requirements for Future Internet traffic management mechanisms, the paper provides an extensive overview of existing mechanisms in literature, assesses them w.r.t. the aforementioned requirements, and qualitatively estimates the expected optimization potential and gain, as well as provides hint for their potential extension and exploitation within the challenging environment of the Future Internet.
• Dynamic Bandwidth Allocation for Multiple Network Connections: Improving User QoE and Network Usage of YouTube in Mobile Broadband. Wamser, Florian; Zinner, Thomas; Z Zhu, Jing; Tran-Gia, Phuoc. In ACM SIGCOMM Capacity Sharing Workshop (CSWS 2014). Chicago, IL, USA, 2014.
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  @inproceedings{info3-inproceedings-2014-500, address = {Chicago, IL, USA}, author = {Wamser, Florian and Zinner, Thomas and Z Zhu, Jing and Tran-Gia, Phuoc}, booktitle = {ACM SIGCOMM Capacity Sharing Workshop (CSWS 2014)}, keywords = {demobenefit}, month = {08}, title = {Dynamic Bandwidth Allocation for Multiple Network Connections: Improving User QoE and Network Usage of YouTube in Mobile Broadband}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-500 %A Wamser, Florian %A Zinner, Thomas %A Z Zhu, Jing %A Tran-Gia, Phuoc %B ACM SIGCOMM Capacity Sharing Workshop (CSWS 2014) %C Chicago, IL, USA %D 2014 %T Dynamic Bandwidth Allocation for Multiple Network Connections: Improving User QoE and Network Usage of YouTube in Mobile Broadband
• Performance Model for Waiting Times in Cloud File Synchronization Services. Schwartz, Christian; Hirth, Matthias; Hoßfeld, Tobias; Tran-Gia, Phuoc. In 26th International Teletraffic Congress (ITC). Karlskrona, Sweden, 2014.
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  Over the last few years, the importance of cloud services for file synchronization has been increasing. With the release of network enabled cameras like Google Glass the trend of synchronizing new photos with the cloud has emerged as an important new use case for mobile networks. Multiple stakeholder are interested in optimizing this synchronization process according to different orthogonal metrics. The end user is interested in a fast synchronization of images as well as a low energy consumption of the client used for upload to the network. The network operator requires a low number of network connections per synchronization of a batch of images in order to reduce the signaling load of the mobile network. This paper answers the question if the goals of the stakeholders can be achieved by selecting an appropriate synchronization scheduling mechanism. Therefore, we first present a model for the waiting time of cloud file synchronization services. Second, we perform measurements on the popular Dropbox service to obtain parameters required in the model. Finally, we perform a parameter study over the considered mechanisms and parameters, suggest a preferable algorithm and identify trade-offs favorable for all stakeholders.

  @inproceedings{info3-inproceedings-2014-495, abstract = {Over the last few years, the importance of cloud services for file synchronization has been increasing. With the release of network enabled cameras like Google Glass the trend of synchronizing new photos with the cloud has emerged as an important new use case for mobile networks. Multiple stakeholder are interested in optimizing this synchronization process according to different orthogonal metrics. The end user is interested in a fast synchronization of images as well as a low energy consumption of the client used for upload to the network. The network operator requires a low number of network connections per synchronization of a batch of images in order to reduce the signaling load of the mobile network. This paper answers the question if the goals of the stakeholders can be achieved by selecting an appropriate synchronization scheduling mechanism. Therefore, we first present a model for the waiting time of cloud file synchronization services. Second, we perform measurements on the popular Dropbox service to obtain parameters required in the model. Finally, we perform a parameter study over the considered mechanisms and parameters, suggest a preferable algorithm and identify trade-offs favorable for all stakeholders.}, address = {Karlskrona, Sweden}, author = {Schwartz, Christian and Hirth, Matthias and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {26th International Teletraffic Congress (ITC)}, keywords = {smartenit}, month = {09}, title = {Performance Model for Waiting Times in Cloud File Synchronization Services}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-495 %A Schwartz, Christian %A Hirth, Matthias %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B 26th International Teletraffic Congress (ITC) %C Karlskrona, Sweden %D 2014 %T Performance Model for Waiting Times in Cloud File Synchronization Services %X Over the last few years, the importance of cloud services for file synchronization has been increasing. With the release of network enabled cameras like Google Glass the trend of synchronizing new photos with the cloud has emerged as an important new use case for mobile networks. Multiple stakeholder are interested in optimizing this synchronization process according to different orthogonal metrics. The end user is interested in a fast synchronization of images as well as a low energy consumption of the client used for upload to the network. The network operator requires a low number of network connections per synchronization of a batch of images in order to reduce the signaling load of the mobile network. This paper answers the question if the goals of the stakeholders can be achieved by selecting an appropriate synchronization scheduling mechanism. Therefore, we first present a model for the waiting time of cloud file synchronization services. Second, we perform measurements on the popular Dropbox service to obtain parameters required in the model. Finally, we perform a parameter study over the considered mechanisms and parameters, suggest a preferable algorithm and identify trade-offs favorable for all stakeholders.
• Implementing Application-Aware Resource Allocation on a Home Gateway for the Example of YouTube. Wamser, Florian; Iffländer, Lukas; Zinner, Thomas; Tran-Gia, Phuoc. In Mobile Networks and Management, Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering. Würzburg, Germany, 2014.
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  Today’s Internet does not offer any quality level beyond best effort for the majority of applications used by private customers. If multiple customers with heterogeneous applications share a bottleneck link to the Internet, this often leads to quality deterioration for the customers. This particularly holds for home networks with smallband Internet access and for home networks with resource limitation like a bad channel quality within a wireless network. For such cases, the best effort allocation of resources between heterogeneous applications leads to an unfair distribution of the application quality among the users. To provide a similar application quality for all users, we propose to implement an application-oriented resource management on a home gateway. Therefore, allocation mechanisms need to be implemented such as the prioritization of network flows. Furthermore, a component monitoring the application quality and dynamically triggering these mechanisms is required. We show the feasibility of this concept by the implementation of an application monitor for YouTube on a standard home gateway. The gateway estimates the YouTube video buffers and prioritizes the video clip before the playback buffer depletes.

  @inproceedings{info3-inproceedings-2014-504, abstract = {Today’s Internet does not offer any quality level beyond best effort for the majority of applications used by private customers. If multiple customers with heterogeneous applications share a bottleneck link to the Internet, this often leads to quality deterioration for the customers. This particularly holds for home networks with smallband Internet access and for home networks with resource limitation like a bad channel quality within a wireless network. For such cases, the best effort allocation of resources between heterogeneous applications leads to an unfair distribution of the application quality among the users. To provide a similar application quality for all users, we propose to implement an application-oriented resource management on a home gateway. Therefore, allocation mechanisms need to be implemented such as the prioritization of network flows. Furthermore, a component monitoring the application quality and dynamically triggering these mechanisms is required. We show the feasibility of this concept by the implementation of an application monitor for YouTube on a standard home gateway. The gateway estimates the YouTube video buffers and prioritizes the video clip before the playback buffer depletes.}, address = {Würzburg, Germany}, author = {Wamser, Florian and Iffländer, Lukas and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {Mobile Networks and Management, Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering}, keywords = {demobenefit}, month = {09}, title = {Implementing Application-Aware Resource Allocation on a Home Gateway for the Example of YouTube}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-504 %A Wamser, Florian %A Iffländer, Lukas %A Zinner, Thomas %A Tran-Gia, Phuoc %B Mobile Networks and Management, Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering %C Würzburg, Germany %D 2014 %T Implementing Application-Aware Resource Allocation on a Home Gateway for the Example of YouTube %X Today’s Internet does not offer any quality level beyond best effort for the majority of applications used by private customers. If multiple customers with heterogeneous applications share a bottleneck link to the Internet, this often leads to quality deterioration for the customers. This particularly holds for home networks with smallband Internet access and for home networks with resource limitation like a bad channel quality within a wireless network. For such cases, the best effort allocation of resources between heterogeneous applications leads to an unfair distribution of the application quality among the users. To provide a similar application quality for all users, we propose to implement an application-oriented resource management on a home gateway. Therefore, allocation mechanisms need to be implemented such as the prioritization of network flows. Furthermore, a component monitoring the application quality and dynamically triggering these mechanisms is required. We show the feasibility of this concept by the implementation of an application monitor for YouTube on a standard home gateway. The gateway estimates the YouTube video buffers and prioritizes the video clip before the playback buffer depletes.
• Catching the Download Train: Energy-efficient File Downloading On Smartphones. Ickin, Selim; Zinner, Thomas; Wac, Katarzyna; Fiedler, Markus. In Workshop on End-to-end Green Cellular Networks (Proceedings of 26th ITC Teletraffic Conference). Karlskrona, 2014.
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  @inproceedings{info3-inproceedings-2014-521, address = {Karlskrona}, author = {Ickin, Selim and Zinner, Thomas and Wac, Katarzyna and Fiedler, Markus}, booktitle = {Workshop on End-to-end Green Cellular Networks (Proceedings of 26th ITC Teletraffic Conference)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Catching the Download Train: Energy-efficient File Downloading On Smartphones}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-521 %A Ickin, Selim %A Zinner, Thomas %A Wac, Katarzyna %A Fiedler, Markus %B Workshop on End-to-end Green Cellular Networks (Proceedings of 26th ITC Teletraffic Conference) %C Karlskrona %D 2014 %T Catching the Download Train: Energy-efficient File Downloading On Smartphones
• Socially-aware Management of New Overlay Applications Traffic - The Optimization Potentials of the SmartenIT Approach. Wajda, Krzysztof; Stankiewicz, Rafal; Dulinski, Zbigniew; Hoßfeld, Tobias; Seufert, Michael; Hausheer, David; Wichtlhuber, Matthias; Papafili, Ioanna; Dramitinos, Manos; Cruschelli, Paolo; Soursos, Sergios; Lapacz, Roman; Stiller, Burkhard. In 6th International Conference on Mobile Networks and Management (MONAMI). Würzburg, Germany, 2014.
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  Today`s overlay-based mobile cloud applications determine a challenge to operators and cloud providers in terms of increasing traffic demands and energy costs. The social-aware management of overlay traffic is a promising optimization approach, which shows potential for improvements by exploiting social information. This paper identifies key stakeholders and their roles in the service provisioning value chain and outlines major markets and optimization potentials. Accordingly, two scenarios are developed: the end user focused scenario aming at increased QoE for end users, and the operator focused scenario targeting at the highest operating efficiency in terms of low cost and high revenue for the operator. The energy efficiency plays a major role as a key performance metric in both scenarios. SmartenIT`s socially-aware management approach is illustrated based on two example mechanisms for traffic optimization: the home router sharing mechanism (HORST) on the end user side, as well as the dynamic traffic management mechanism (DTM) on the operator side. The paper is concluded by a first sketch of SmartenIT`s architecture and its mapping to the two scenarios.

  @inproceedings{info3-inproceedings-2014-501, abstract = {Today`s overlay-based mobile cloud applications determine a challenge to operators and cloud providers in terms of increasing traffic demands and energy costs. The social-aware management of overlay traffic is a promising optimization approach, which shows potential for improvements by exploiting social information. This paper identifies key stakeholders and their roles in the service provisioning value chain and outlines major markets and optimization potentials. Accordingly, two scenarios are developed: the end user focused scenario aming at increased QoE for end users, and the operator focused scenario targeting at the highest operating efficiency in terms of low cost and high revenue for the operator. The energy efficiency plays a major role as a key performance metric in both scenarios. SmartenIT`s socially-aware management approach is illustrated based on two example mechanisms for traffic optimization: the home router sharing mechanism (HORST) on the end user side, as well as the dynamic traffic management mechanism (DTM) on the operator side. The paper is concluded by a first sketch of SmartenIT`s architecture and its mapping to the two scenarios.}, address = {Würzburg, Germany}, author = {Wajda, Krzysztof and Stankiewicz, Rafal and Dulinski, Zbigniew and Hoßfeld, Tobias and Seufert, Michael and Hausheer, David and Wichtlhuber, Matthias and Papafili, Ioanna and Dramitinos, Manos and Cruschelli, Paolo and Soursos, Sergios and Lapacz, Roman and Stiller, Burkhard}, booktitle = {6th International Conference on Mobile Networks and Management (MONAMI)}, keywords = {smartenit}, month = {09}, title = {Socially-aware Management of New Overlay Applications Traffic - The Optimization Potentials of the SmartenIT Approach}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-501 %A Wajda, Krzysztof %A Stankiewicz, Rafal %A Dulinski, Zbigniew %A Hoßfeld, Tobias %A Seufert, Michael %A Hausheer, David %A Wichtlhuber, Matthias %A Papafili, Ioanna %A Dramitinos, Manos %A Cruschelli, Paolo %A Soursos, Sergios %A Lapacz, Roman %A Stiller, Burkhard %B 6th International Conference on Mobile Networks and Management (MONAMI) %C Würzburg, Germany %D 2014 %T Socially-aware Management of New Overlay Applications Traffic - The Optimization Potentials of the SmartenIT Approach %X Today`s overlay-based mobile cloud applications determine a challenge to operators and cloud providers in terms of increasing traffic demands and energy costs. The social-aware management of overlay traffic is a promising optimization approach, which shows potential for improvements by exploiting social information. This paper identifies key stakeholders and their roles in the service provisioning value chain and outlines major markets and optimization potentials. Accordingly, two scenarios are developed: the end user focused scenario aming at increased QoE for end users, and the operator focused scenario targeting at the highest operating efficiency in terms of low cost and high revenue for the operator. The energy efficiency plays a major role as a key performance metric in both scenarios. SmartenIT`s socially-aware management approach is illustrated based on two example mechanisms for traffic optimization: the home router sharing mechanism (HORST) on the end user side, as well as the dynamic traffic management mechanism (DTM) on the operator side. The paper is concluded by a first sketch of SmartenIT`s architecture and its mapping to the two scenarios.
• Assessing Effect Sizes of Influence Factors Towards a QoE Model for HTTP Adaptive Streaming. Hoßfeld, Tobias; Seufert, Michael; Sieber, Christian; Zinner, Thomas. In 6th International Workshop on Quality of Multimedia Experience (QoMEX). Singapore, 2014.
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  HTTP Adaptive Streaming (HAS) is employed by more and more video streaming services in the Internet. It allows to adapt the downloaded video quality to the current network conditions, and thus, avoids stalling (i.e., playback interruptions) to the greatest possible extend. The adaptation of video streams is done by switching between different quality representation levels, which influences the user perceived quality of the video stream. In this work, the influence of several adaptation parameters, namely, switch amplitude (i.e., quality level difference), switching frequency, and recency effects, on Quality of Experience (QoE) is investigated. Therefore, crowdsourcing experiments were conducted in order to collect subjective ratings for different adaptation-related test conditions. The results of these subjective studies indicate the influence of the adaptation parameters, and based on these findings a simplified QoE model for HAS is presented, which only relies on the switch amplitude and the playback time of each layer.

  @inproceedings{info3-inproceedings-2014-503, abstract = {HTTP Adaptive Streaming (HAS) is employed by more and more video streaming services in the Internet. It allows to adapt the downloaded video quality to the current network conditions, and thus, avoids stalling (i.e., playback interruptions) to the greatest possible extend. The adaptation of video streams is done by switching between different quality representation levels, which influences the user perceived quality of the video stream. In this work, the influence of several adaptation parameters, namely, switch amplitude (i.e., quality level difference), switching frequency, and recency effects, on Quality of Experience (QoE) is investigated. Therefore, crowdsourcing experiments were conducted in order to collect subjective ratings for different adaptation-related test conditions. The results of these subjective studies indicate the influence of the adaptation parameters, and based on these findings a simplified QoE model for HAS is presented, which only relies on the switch amplitude and the playback time of each layer.}, address = {Singapore}, author = {Hoßfeld, Tobias and Seufert, Michael and Sieber, Christian and Zinner, Thomas}, booktitle = {6th International Workshop on Quality of Multimedia Experience (QoMEX)}, keywords = {smartenit}, month = {09}, title = {Assessing Effect Sizes of Influence Factors Towards a QoE Model for HTTP Adaptive Streaming}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-503 %A Hoßfeld, Tobias %A Seufert, Michael %A Sieber, Christian %A Zinner, Thomas %B 6th International Workshop on Quality of Multimedia Experience (QoMEX) %C Singapore %D 2014 %T Assessing Effect Sizes of Influence Factors Towards a QoE Model for HTTP Adaptive Streaming %X HTTP Adaptive Streaming (HAS) is employed by more and more video streaming services in the Internet. It allows to adapt the downloaded video quality to the current network conditions, and thus, avoids stalling (i.e., playback interruptions) to the greatest possible extend. The adaptation of video streams is done by switching between different quality representation levels, which influences the user perceived quality of the video stream. In this work, the influence of several adaptation parameters, namely, switch amplitude (i.e., quality level difference), switching frequency, and recency effects, on Quality of Experience (QoE) is investigated. Therefore, crowdsourcing experiments were conducted in order to collect subjective ratings for different adaptation-related test conditions. The results of these subjective studies indicate the influence of the adaptation parameters, and based on these findings a simplified QoE model for HAS is presented, which only relies on the switch amplitude and the playback time of each layer.
• Deriving the Employee-perceived Application Quality in Enterprise IT Infrastructures using Information from Ticketing Systems. Schwarzmann, Susanna; Zinner, Thomas; Hirth, Matthias. In Workshop on Knowledge Discovery, Data Mining and Machine Learning (KDML 2014). Aachen, Germany, 2014.
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  @inproceedings{info3-inproceedings-2014-502, address = {Aachen, Germany}, author = {Schwarzmann, Susanna and Zinner, Thomas and Hirth, Matthias}, booktitle = {Workshop on Knowledge Discovery, Data Mining and Machine Learning (KDML 2014)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Deriving the Employee-perceived Application Quality in Enterprise IT Infrastructures using Information from Ticketing Systems}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-502 %A Schwarzmann, Susanna %A Zinner, Thomas %A Hirth, Matthias %B Workshop on Knowledge Discovery, Data Mining and Machine Learning (KDML 2014) %C Aachen, Germany %D 2014 %T Deriving the Employee-perceived Application Quality in Enterprise IT Infrastructures using Information from Ticketing Systems
• Survey of Web-based Crowdsourcing Frameworks for Subjective Quality Assessment. Hoßfeld, Tobias; Hirth, Matthias; Korshunov, Pavel; Hanhart, Philippe; Gardlo, Bruno; Keimel, Christian; Timmerer, Christian. In 16th International Workshop on Multimedia Signal Processing. Jakarta, Indonesia, 2014.
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  The popularity of the crowdsourcing for performing various tasks online increased significantly in the past few years. The low cost and flexibility of crowdsourcing, in particular, attracted researchers in the field of subjective multimedia evaluations and Quality of Experience (QoE). Since online assessment of multimedia content is challenging, several dedicated frameworks were created to aid in the designing of the tests, including the support of the testing methodologies like ACR, DCR, and PC, setting up the tasks, training sessions, screening of the subjects, and storage of the resulted data. In this paper, we focus on the web-based frameworks for multimedia quality assessments that support commonly used crowdsourcing platforms such as Amazon Mechanical Turk and Microworkers. We provide a detailed overview of the crowdsourcing frameworks and evaluate them to aid researchers in the field of QoE assessment in the selection of frameworks and crowdsourcing platforms that are adequate for their experiments.

  @inproceedings{info3-inproceedings-2014-498, abstract = {The popularity of the crowdsourcing for performing various tasks online increased significantly in the past few years. The low cost and flexibility of crowdsourcing, in particular, attracted researchers in the field of subjective multimedia evaluations and Quality of Experience (QoE). Since online assessment of multimedia content is challenging, several dedicated frameworks were created to aid in the designing of the tests, including the support of the testing methodologies like ACR, DCR, and PC, setting up the tasks, training sessions, screening of the subjects, and storage of the resulted data. In this paper, we focus on the web-based frameworks for multimedia quality assessments that support commonly used crowdsourcing platforms such as Amazon Mechanical Turk and Microworkers. We provide a detailed overview of the crowdsourcing frameworks and evaluate them to aid researchers in the field of QoE assessment in the selection of frameworks and crowdsourcing platforms that are adequate for their experiments.}, address = {Jakarta, Indonesia}, author = {Hoßfeld, Tobias and Hirth, Matthias and Korshunov, Pavel and Hanhart, Philippe and Gardlo, Bruno and Keimel, Christian and Timmerer, Christian}, booktitle = {16th International Workshop on Multimedia Signal Processing}, keywords = {crowdsourcing-design}, month = {09}, title = {Survey of Web-based Crowdsourcing Frameworks for Subjective Quality Assessment}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-498 %A Hoßfeld, Tobias %A Hirth, Matthias %A Korshunov, Pavel %A Hanhart, Philippe %A Gardlo, Bruno %A Keimel, Christian %A Timmerer, Christian %B 16th International Workshop on Multimedia Signal Processing %C Jakarta, Indonesia %D 2014 %T Survey of Web-based Crowdsourcing Frameworks for Subjective Quality Assessment %X The popularity of the crowdsourcing for performing various tasks online increased significantly in the past few years. The low cost and flexibility of crowdsourcing, in particular, attracted researchers in the field of subjective multimedia evaluations and Quality of Experience (QoE). Since online assessment of multimedia content is challenging, several dedicated frameworks were created to aid in the designing of the tests, including the support of the testing methodologies like ACR, DCR, and PC, setting up the tasks, training sessions, screening of the subjects, and storage of the resulted data. In this paper, we focus on the web-based frameworks for multimedia quality assessments that support commonly used crowdsourcing platforms such as Amazon Mechanical Turk and Microworkers. We provide a detailed overview of the crowdsourcing frameworks and evaluate them to aid researchers in the field of QoE assessment in the selection of frameworks and crowdsourcing platforms that are adequate for their experiments.
• The Impact of Adaptation Strategies on Perceived Quality of HTTP Adaptive Streaming. Egger, Sebastian; Gardlo, Bruno; Seufert, Michael; Schatz, Raimund. In 1st Workshop on Design, Quality and Deployment of Adaptive Video Streaming (VideoNext). Sydney, Australia, 2014.
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  Changing network conditions like bandwidth fluctuations and resulting bad user experience issues (e.g. video freezes) pose severe challenges to Internet video streaming. To address this problem, an increasing number of video services utilizes HTTP adaptive streaming (HAS). HAS enables service providers to improve Quality of Experience (QoE) and resource utilization by incorporating information from different layers. However, these adaptation possibilities of HAS also introduce new perceivable impairments such as the fluctuation of audiovisual quality levels over time, which in turn lead to novel QoE-related research questions.The main contribution of this paper is the formulation of open research questions as well as a thorough systematic user-centric analysis of different quality adaptation dimensions and strategies. The underlying data has been acquired through two crowdsourcing and one lab study. The results provide guidance w.r.t. which encoding dimensions are combined best for the creation of the adaptation set and what type of adaptation strategy should be used. Furthermore it provides insights on the impact of adaptation frequency and the true QoE gain of adaptation over stallings.

  @inproceedings{info3-inproceedings-2014-507, abstract = {Changing network conditions like bandwidth fluctuations and resulting bad user experience issues (e.g. video freezes) pose severe challenges to Internet video streaming. To address this problem, an increasing number of video services utilizes HTTP adaptive streaming (HAS). HAS enables service providers to improve Quality of Experience (QoE) and resource utilization by incorporating information from different layers. However, these adaptation possibilities of HAS also introduce new perceivable impairments such as the fluctuation of audiovisual quality levels over time, which in turn lead to novel QoE-related research questions.The main contribution of this paper is the formulation of open research questions as well as a thorough systematic user-centric analysis of different quality adaptation dimensions and strategies. The underlying data has been acquired through two crowdsourcing and one lab study. The results provide guidance w.r.t. which encoding dimensions are combined best for the creation of the adaptation set and what type of adaptation strategy should be used. Furthermore it provides insights on the impact of adaptation frequency and the true QoE gain of adaptation over stallings.}, address = {Sydney, Australia}, author = {Egger, Sebastian and Gardlo, Bruno and Seufert, Michael and Schatz, Raimund}, booktitle = {1st Workshop on Design, Quality and Deployment of Adaptive Video Streaming (VideoNext)}, keywords = {sys:hidden:inproceedings}, month = 12, title = {The Impact of Adaptation Strategies on Perceived Quality of HTTP Adaptive Streaming}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-507 %A Egger, Sebastian %A Gardlo, Bruno %A Seufert, Michael %A Schatz, Raimund %B 1st Workshop on Design, Quality and Deployment of Adaptive Video Streaming (VideoNext) %C Sydney, Australia %D 2014 %T The Impact of Adaptation Strategies on Perceived Quality of HTTP Adaptive Streaming %X Changing network conditions like bandwidth fluctuations and resulting bad user experience issues (e.g. video freezes) pose severe challenges to Internet video streaming. To address this problem, an increasing number of video services utilizes HTTP adaptive streaming (HAS). HAS enables service providers to improve Quality of Experience (QoE) and resource utilization by incorporating information from different layers. However, these adaptation possibilities of HAS also introduce new perceivable impairments such as the fluctuation of audiovisual quality levels over time, which in turn lead to novel QoE-related research questions.The main contribution of this paper is the formulation of open research questions as well as a thorough systematic user-centric analysis of different quality adaptation dimensions and strategies. The underlying data has been acquired through two crowdsourcing and one lab study. The results provide guidance w.r.t. which encoding dimensions are combined best for the creation of the adaptation set and what type of adaptation strategy should be used. Furthermore it provides insights on the impact of adaptation frequency and the true QoE gain of adaptation over stallings.
• Visions and Challenges for Sensor Network Collaboration in the Cloud. Oechsner, Simon; Bellalta, Boris; Dimitrova, Desislava; Hoßfeld, Tobias. In The Eighth International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS-2014). Birmingham, UK, 2014.
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  The rapid growth in sensor network coverage, aided by the use of smartphones as capable sensing devices, leads to an enormous amount of gathered data from a multitude of different sources. However, generally data from one specific sensor network is only used by a very limited set of users and applications. This wastes a potentially greater usefulness for other, related data sinks that could use this additional input to improve their performance or services. In this paper, we outline visions and challenges for a widespread application of sensor network collaboration in the sense of sharing and exchanging information. We also describe a basic cloud-based architecture enabling this collaboration by providing the required support to store, manage and combine the gathered data. In particular, we include collaboration between sensor networks themselves to optimize performance, a facet that was up to now neglected in literature.

  @inproceedings{info3-inproceedings-2014-491, abstract = {The rapid growth in sensor network coverage, aided by the use of smartphones as capable sensing devices, leads to an enormous amount of gathered data from a multitude of different sources. However, generally data from one specific sensor network is only used by a very limited set of users and applications. This wastes a potentially greater usefulness for other, related data sinks that could use this additional input to improve their performance or services. In this paper, we outline visions and challenges for a widespread application of sensor network collaboration in the sense of sharing and exchanging information. We also describe a basic cloud-based architecture enabling this collaboration by providing the required support to store, manage and combine the gathered data. In particular, we include collaboration between sensor networks themselves to optimize performance, a facet that was up to now neglected in literature.}, address = {Birmingham, UK}, author = {Oechsner, Simon and Bellalta, Boris and Dimitrova, Desislava and Hoßfeld, Tobias}, booktitle = {The Eighth International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS-2014)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Visions and Challenges for Sensor Network Collaboration in the Cloud}, year = 2014 }

  %0 Conference Paper %1 info3-inproceedings-2014-491 %A Oechsner, Simon %A Bellalta, Boris %A Dimitrova, Desislava %A Hoßfeld, Tobias %B The Eighth International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS-2014) %C Birmingham, UK %D 2014 %T Visions and Challenges for Sensor Network Collaboration in the Cloud %X The rapid growth in sensor network coverage, aided by the use of smartphones as capable sensing devices, leads to an enormous amount of gathered data from a multitude of different sources. However, generally data from one specific sensor network is only used by a very limited set of users and applications. This wastes a potentially greater usefulness for other, related data sinks that could use this additional input to improve their performance or services. In this paper, we outline visions and challenges for a widespread application of sensor network collaboration in the sense of sharing and exchanging information. We also describe a basic cloud-based architecture enabling this collaboration by providing the required support to store, manage and combine the gathered data. In particular, we include collaboration between sensor networks themselves to optimize performance, a facet that was up to now neglected in literature.

• Implementation and User-centric Comparison of a Novel Adaptation Logic for DASH with SVC. Sieber, Christian; Hoßfeld, Tobias; Zinner, Thomas; Tran-Gia, Phuoc; Timmerer, Christian. In IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan), Best Paper Award. Ghent, Belgium, 2013.
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  The MPEG-DASH standard allows the client-centric access to different representations of video content via the HTTP protocol. The client can flexibly switch between different qualities, i.e., different bit rates and thus avoid waiting times during the video playback due to empty playback buffers. However, quality switches and the playback of lower qualities is perceived by the user which may reduce the Quality of Experience (QoE). Therefore, novel algorithms are required which manage the streaming behavior with respect to the user's requirements and which do not waste network resources. As indicated by recent studies, scalable video coding (SVC) may use the current network and content distribution infrastructure in a more efficient way than with single layer codecs. The contribution of this paper is the design and the implementation of a novel DASH/SVC streaming algorithm. By means of measurements in a test-bed, its performance and benefits are evaluated and compared to existing algorithms from an user-centric view point with objective performance metrics. Our findings show that the proposed algorithm outperforms other DASH mechanisms in terms of video quality, low switching frequency and usage of the available resources in a realistic mobile network scenario. This is a first step towards true QoE management of video streaming in the Internet with DASH and SVC.

  @inproceedings{info3-inproceedings-2013-462, abstract = {The MPEG-DASH standard allows the client-centric access to different representations of video content via the HTTP protocol. The client can flexibly switch between different qualities, i.e., different bit rates and thus avoid waiting times during the video playback due to empty playback buffers. However, quality switches and the playback of lower qualities is perceived by the user which may reduce the Quality of Experience (QoE). Therefore, novel algorithms are required which manage the streaming behavior with respect to the user's requirements and which do not waste network resources. As indicated by recent studies, scalable video coding (SVC) may use the current network and content distribution infrastructure in a more efficient way than with single layer codecs. The contribution of this paper is the design and the implementation of a novel DASH/SVC streaming algorithm. By means of measurements in a test-bed, its performance and benefits are evaluated and compared to existing algorithms from an user-centric view point with objective performance metrics. Our findings show that the proposed algorithm outperforms other DASH mechanisms in terms of video quality, low switching frequency and usage of the available resources in a realistic mobile network scenario. This is a first step towards true QoE management of video streaming in the Internet with DASH and SVC.}, address = {Ghent, Belgium}, author = {Sieber, Christian and Hoßfeld, Tobias and Zinner, Thomas and Tran-Gia, Phuoc and Timmerer, Christian}, booktitle = {IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan), Best Paper Award}, keywords = {smartenit}, month = {05}, title = {Implementation and User-centric Comparison of a Novel Adaptation Logic for DASH with SVC}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-462 %A Sieber, Christian %A Hoßfeld, Tobias %A Zinner, Thomas %A Tran-Gia, Phuoc %A Timmerer, Christian %B IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan), Best Paper Award %C Ghent, Belgium %D 2013 %T Implementation and User-centric Comparison of a Novel Adaptation Logic for DASH with SVC %X The MPEG-DASH standard allows the client-centric access to different representations of video content via the HTTP protocol. The client can flexibly switch between different qualities, i.e., different bit rates and thus avoid waiting times during the video playback due to empty playback buffers. However, quality switches and the playback of lower qualities is perceived by the user which may reduce the Quality of Experience (QoE). Therefore, novel algorithms are required which manage the streaming behavior with respect to the user's requirements and which do not waste network resources. As indicated by recent studies, scalable video coding (SVC) may use the current network and content distribution infrastructure in a more efficient way than with single layer codecs. The contribution of this paper is the design and the implementation of a novel DASH/SVC streaming algorithm. By means of measurements in a test-bed, its performance and benefits are evaluated and compared to existing algorithms from an user-centric view point with objective performance metrics. Our findings show that the proposed algorithm outperforms other DASH mechanisms in terms of video quality, low switching frequency and usage of the available resources in a realistic mobile network scenario. This is a first step towards true QoE management of video streaming in the Internet with DASH and SVC.
• Evaluation of Video Quality Monitoring based on Pre-computed Frame Distortions. Klein, Dominik; Zinner, Thomas; Borchert, Kathrin; Lange, Stanislav; Singeorzan, Vlad; Schmid, Matthias. In 19th EUNICE Workshop on Advances in Communication Networking, Best Paper Award. Chemnitz, Germany, 2013.
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  A large fraction of the current Internet traffic is caused by video streaming. Due to the growing expectations of video consumers, monitoring video applications is getting more and more important for network and service providers. In a previous work, we proposed a video quality monitoring solution which utilizes the full reference SSIM metric to improve the monitoring in the network by distributing pre-computed distortion information induced by frame losses. To improve scalability, we introduced a less complex algorithm which infers the distortion for higher loss scenarios from single loss scenarios and inter-frame dependencies. In this work, we evaluate the accuracy of our algorithm by comparing it with the exact calculation of the SSIM metric for different frame loss scenarios. We further consider different high definition test video sequences and group of picture structures and investigate the influence on the accuracy of our proposed approximation.

  @inproceedings{info3-inproceedings-2013-474, abstract = {A large fraction of the current Internet traffic is caused by video streaming. Due to the growing expectations of video consumers, monitoring video applications is getting more and more important for network and service providers. In a previous work, we proposed a video quality monitoring solution which utilizes the full reference SSIM metric to improve the monitoring in the network by distributing pre-computed distortion information induced by frame losses. To improve scalability, we introduced a less complex algorithm which infers the distortion for higher loss scenarios from single loss scenarios and inter-frame dependencies. In this work, we evaluate the accuracy of our algorithm by comparing it with the exact calculation of the SSIM metric for different frame loss scenarios. We further consider different high definition test video sequences and group of picture structures and investigate the influence on the accuracy of our proposed approximation.}, address = {Chemnitz, Germany}, author = {Klein, Dominik and Zinner, Thomas and Borchert, Kathrin and Lange, Stanislav and Singeorzan, Vlad and Schmid, Matthias}, booktitle = {19th EUNICE Workshop on Advances in Communication Networking, Best Paper Award}, keywords = {video-quality}, month = {08}, title = {Evaluation of Video Quality Monitoring based on Pre-computed Frame Distortions}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-474 %A Klein, Dominik %A Zinner, Thomas %A Borchert, Kathrin %A Lange, Stanislav %A Singeorzan, Vlad %A Schmid, Matthias %B 19th EUNICE Workshop on Advances in Communication Networking, Best Paper Award %C Chemnitz, Germany %D 2013 %T Evaluation of Video Quality Monitoring based on Pre-computed Frame Distortions %X A large fraction of the current Internet traffic is caused by video streaming. Due to the growing expectations of video consumers, monitoring video applications is getting more and more important for network and service providers. In a previous work, we proposed a video quality monitoring solution which utilizes the full reference SSIM metric to improve the monitoring in the network by distributing pre-computed distortion information induced by frame losses. To improve scalability, we introduced a less complex algorithm which infers the distortion for higher loss scenarios from single loss scenarios and inter-frame dependencies. In this work, we evaluate the accuracy of our algorithm by comparing it with the exact calculation of the SSIM metric for different frame loss scenarios. We further consider different high definition test video sequences and group of picture structures and investigate the influence on the accuracy of our proposed approximation.
• Towards an understanding of visual appeal in website design. Varela, Martin; Mäki, Toni; Skorin-Kapov, Lea; Hoßfeld, Tobias. In Fifth International Workshop on Quality of Multimedia Experience (QoMEX 2013). Klagenfurt, Austria, 2013.
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  Visual appeal (VA), as judged by users accessing different websites, has been shown to impact overall user preferences and satisfaction. In the context of Web Quality of Experience (QoE), we hypothesize that VA has a non-trivial impact on end user quality perception and hence needs to be accounted for when modeling overall Web QoE. In this paper, we aim to quantify the impact of VA factors on perceived visual design quality for different types of tested websites. We carried out two large-scale (>350 users each) crowd-sourced campaigns to test the influence of several factors often found in design best practices recommendations. While results have identified color goodness and font goodness as Key Influence Factors (KIF) for VA, an analysis of user demographics has further shown a strong impact of user's origin on subjective ratings. By quantifying the impact of identified KIFs on VA, we provide guidelines for successful VA manipulations to be considered in future Web QoE subjective tests.

  @inproceedings{info3-inproceedings-2013-468, abstract = {Visual appeal (VA), as judged by users accessing different websites, has been shown to impact overall user preferences and satisfaction. In the context of Web Quality of Experience (QoE), we hypothesize that VA has a non-trivial impact on end user quality perception and hence needs to be accounted for when modeling overall Web QoE. In this paper, we aim to quantify the impact of VA factors on perceived visual design quality for different types of tested websites. We carried out two large-scale (>350 users each) crowd-sourced campaigns to test the influence of several factors often found in design best practices recommendations. While results have identified color goodness and font goodness as Key Influence Factors (KIF) for VA, an analysis of user demographics has further shown a strong impact of user's origin on subjective ratings. By quantifying the impact of identified KIFs on VA, we provide guidelines for successful VA manipulations to be considered in future Web QoE subjective tests.}, address = {Klagenfurt, Austria}, author = {Varela, Martin and Mäki, Toni and Skorin-Kapov, Lea and Hoßfeld, Tobias}, booktitle = {Fifth International Workshop on Quality of Multimedia Experience (QoMEX 2013)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Towards an understanding of visual appeal in website design}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-468 %A Varela, Martin %A Mäki, Toni %A Skorin-Kapov, Lea %A Hoßfeld, Tobias %B Fifth International Workshop on Quality of Multimedia Experience (QoMEX 2013) %C Klagenfurt, Austria %D 2013 %T Towards an understanding of visual appeal in website design %X Visual appeal (VA), as judged by users accessing different websites, has been shown to impact overall user preferences and satisfaction. In the context of Web Quality of Experience (QoE), we hypothesize that VA has a non-trivial impact on end user quality perception and hence needs to be accounted for when modeling overall Web QoE. In this paper, we aim to quantify the impact of VA factors on perceived visual design quality for different types of tested websites. We carried out two large-scale (>350 users each) crowd-sourced campaigns to test the influence of several factors often found in design best practices recommendations. While results have identified color goodness and font goodness as Key Influence Factors (KIF) for VA, an analysis of user demographics has further shown a strong impact of user's origin on subjective ratings. By quantifying the impact of identified KIFs on VA, we provide guidelines for successful VA manipulations to be considered in future Web QoE subjective tests.
• To Pool or not to Pool: A Comparison of Temporal Pooling Methods for HTTP Adaptive Video Streaming. Seufert, Michael; Slanina, Martin; Egger, Sebastian; Kottkamp, Meik. In 5th International Workshop on Quality of Multimedia Experience (QoMEX). Klagenfurt, Austria, 2013.
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  Current objective video quality metrics typically estimate video quality for short video sequences (10 to 15 sec) of constant quality. However, customers of video services typically watch longer sequences of videos which are more and more delivered via adaptive streaming methods such as HTTP adaptive streaming (HAS). Typically a viewing session in such a setting contains several different video qualities over time. In order to express this in an overall score for the whole viewing session several temporal pooling methods have been proposed in the related work. Within this paper we set out to compare the performance of different temporal pooling methods for the prediction of Quality of Experience (QoE) for HTTP video streams with varying qualities. We perform this comparison based on ground truth rating data gathered in a crowdsourcing study in the context of the NGMN P-SERQU project. As input data for the models we use bjective video quality metrics such as PSNR, SSIM but also very basic inputs such as the bitrate of the clips only. Our results show that certain pooling methods perform clearly better than others. These results can help in identifying well performing temporal pooling methods in the context of HAS.

  @inproceedings{info3-inproceedings-2013-465, abstract = {Current objective video quality metrics typically estimate video quality for short video sequences (10 to 15 sec) of constant quality. However, customers of video services typically watch longer sequences of videos which are more and more delivered via adaptive streaming methods such as HTTP adaptive streaming (HAS). Typically a viewing session in such a setting contains several different video qualities over time. In order to express this in an overall score for the whole viewing session several temporal pooling methods have been proposed in the related work. Within this paper we set out to compare the performance of different temporal pooling methods for the prediction of Quality of Experience (QoE) for HTTP video streams with varying qualities. We perform this comparison based on ground truth rating data gathered in a crowdsourcing study in the context of the NGMN P-SERQU project. As input data for the models we use bjective video quality metrics such as PSNR, SSIM but also very basic inputs such as the bitrate of the clips only. Our results show that certain pooling methods perform clearly better than others. These results can help in identifying well performing temporal pooling methods in the context of HAS.}, address = {Klagenfurt, Austria}, author = {Seufert, Michael and Slanina, Martin and Egger, Sebastian and Kottkamp, Meik}, booktitle = {5th International Workshop on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {To Pool or not to Pool: A Comparison of Temporal Pooling Methods for HTTP Adaptive Video Streaming}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-465 %A Seufert, Michael %A Slanina, Martin %A Egger, Sebastian %A Kottkamp, Meik %B 5th International Workshop on Quality of Multimedia Experience (QoMEX) %C Klagenfurt, Austria %D 2013 %T To Pool or not to Pool: A Comparison of Temporal Pooling Methods for HTTP Adaptive Video Streaming %X Current objective video quality metrics typically estimate video quality for short video sequences (10 to 15 sec) of constant quality. However, customers of video services typically watch longer sequences of videos which are more and more delivered via adaptive streaming methods such as HTTP adaptive streaming (HAS). Typically a viewing session in such a setting contains several different video qualities over time. In order to express this in an overall score for the whole viewing session several temporal pooling methods have been proposed in the related work. Within this paper we set out to compare the performance of different temporal pooling methods for the prediction of Quality of Experience (QoE) for HTTP video streams with varying qualities. We perform this comparison based on ground truth rating data gathered in a crowdsourcing study in the context of the NGMN P-SERQU project. As input data for the models we use bjective video quality metrics such as PSNR, SSIM but also very basic inputs such as the bitrate of the clips only. Our results show that certain pooling methods perform clearly better than others. These results can help in identifying well performing temporal pooling methods in the context of HAS.
• Quality of Experience in Remote Virtual Desktop Services. Casas, Pedro; Seufert, Michael; Egger, Sebastian; Schatz, Raimund. In IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan). Ghent, Belgium, 2013.
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  Remote Virtual Desktop (RVD) services provide flexible and cost-effective means to deliver virtual PCs to end-users. RVD services have been traditionally deployed in enterprise LAN scenarios, where network performance is optimal and the Quality of Experience (QoE) undergone by its users is generally not an issue. However, the need for mobility of RVD users (e.g., remote office, home office, etc.) and the explosion of Cloud-based services have pushed RVD to WAN scenarios, and nowadays it is common to find RVD services running at large datacenters in the Cloud. In such a context, network delay and bandwidth are very dynamic and difficult to guarantee or even to control, and QoE becomes a real bottleneck. In this paper we present a complete study of the QoE undergone by 52 RVD users in controlled subjective lab tests. The study is performed on a dedicated RVD testbed based on Citrix technology, which is the de-facto RVD solution used in enterprise scenarios. The study permits not only to better understand the interplays between network performance (i.e., network delay and bandwidth) and QoE in RVD services, but also provides results on the behavior of RVD users when confronted to variable network conditions w.r.t. their behavior on standard local desktops.

  @inproceedings{info3-inproceedings-2013-463, abstract = {Remote Virtual Desktop (RVD) services provide flexible and cost-effective means to deliver virtual PCs to end-users. RVD services have been traditionally deployed in enterprise LAN scenarios, where network performance is optimal and the Quality of Experience (QoE) undergone by its users is generally not an issue. However, the need for mobility of RVD users (e.g., remote office, home office, etc.) and the explosion of Cloud-based services have pushed RVD to WAN scenarios, and nowadays it is common to find RVD services running at large datacenters in the Cloud. In such a context, network delay and bandwidth are very dynamic and difficult to guarantee or even to control, and QoE becomes a real bottleneck. In this paper we present a complete study of the QoE undergone by 52 RVD users in controlled subjective lab tests. The study is performed on a dedicated RVD testbed based on Citrix technology, which is the de-facto RVD solution used in enterprise scenarios. The study permits not only to better understand the interplays between network performance (i.e., network delay and bandwidth) and QoE in RVD services, but also provides results on the behavior of RVD users when confronted to variable network conditions w.r.t. their behavior on standard local desktops.}, address = {Ghent, Belgium}, author = {Casas, Pedro and Seufert, Michael and Egger, Sebastian and Schatz, Raimund}, booktitle = {IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Quality of Experience in Remote Virtual Desktop Services}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-463 %A Casas, Pedro %A Seufert, Michael %A Egger, Sebastian %A Schatz, Raimund %B IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan) %C Ghent, Belgium %D 2013 %T Quality of Experience in Remote Virtual Desktop Services %X Remote Virtual Desktop (RVD) services provide flexible and cost-effective means to deliver virtual PCs to end-users. RVD services have been traditionally deployed in enterprise LAN scenarios, where network performance is optimal and the Quality of Experience (QoE) undergone by its users is generally not an issue. However, the need for mobility of RVD users (e.g., remote office, home office, etc.) and the explosion of Cloud-based services have pushed RVD to WAN scenarios, and nowadays it is common to find RVD services running at large datacenters in the Cloud. In such a context, network delay and bandwidth are very dynamic and difficult to guarantee or even to control, and QoE becomes a real bottleneck. In this paper we present a complete study of the QoE undergone by 52 RVD users in controlled subjective lab tests. The study is performed on a dedicated RVD testbed based on Citrix technology, which is the de-facto RVD solution used in enterprise scenarios. The study permits not only to better understand the interplays between network performance (i.e., network delay and bandwidth) and QoE in RVD services, but also provides results on the behavior of RVD users when confronted to variable network conditions w.r.t. their behavior on standard local desktops.
• Pippi Longstocking Calculus for Temporal Stimuli Pattern on YouTube QoE. Hoßfeld, Tobias; Strohmeier, Dominik; Raake, Alexander; Schatz, Raimund. In 5th ACM Workshop on Mobile Video (MoVid 2013). Oslo, Norway, 2013.
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  Video streaming over wireless broadband is currently re- sponsible for half of the world-wide mobile data traffic and its share is expected to even further increase. Therefore, mobile operators need to understand how Quality of Ex- perience (QoE) of mobile video streaming is impacted by through the network delivery. Due to HTTP video stream- ing used by video portals like YouTube or NetFlix, problems or insufficient resources in the networks manifest as stalling events during service consumption on an end user device. In this paper, we discuss the challenges for QoE monitoring for HTTP-based mobile video regarding three aspects. First, the impact of different patterns in terms of stalling event frequency and length on QoE is quantified on behalf of a study on YouTube. Second, we evaluate predictive power of aggregate measures like total stalling time. Third, we discuss the resulting consequences and challenges for mobile video QoE modeling, monitoring and provisioning.

  @inproceedings{info3-inproceedings-2013-459, abstract = {Video streaming over wireless broadband is currently re- sponsible for half of the world-wide mobile data traffic and its share is expected to even further increase. Therefore, mobile operators need to understand how Quality of Ex- perience (QoE) of mobile video streaming is impacted by through the network delivery. Due to HTTP video stream- ing used by video portals like YouTube or NetFlix, problems or insufficient resources in the networks manifest as stalling events during service consumption on an end user device. In this paper, we discuss the challenges for QoE monitoring for HTTP-based mobile video regarding three aspects. First, the impact of different patterns in terms of stalling event frequency and length on QoE is quantified on behalf of a study on YouTube. Second, we evaluate predictive power of aggregate measures like total stalling time. Third, we discuss the resulting consequences and challenges for mobile video QoE modeling, monitoring and provisioning.}, address = {Oslo, Norway}, author = {Hoßfeld, Tobias and Strohmeier, Dominik and Raake, Alexander and Schatz, Raimund}, booktitle = {5th ACM Workshop on Mobile Video (MoVid 2013)}, keywords = {demobenefit}, month = {02}, title = {Pippi Longstocking Calculus for Temporal Stimuli Pattern on YouTube QoE}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-459 %A Hoßfeld, Tobias %A Strohmeier, Dominik %A Raake, Alexander %A Schatz, Raimund %B 5th ACM Workshop on Mobile Video (MoVid 2013) %C Oslo, Norway %D 2013 %T Pippi Longstocking Calculus for Temporal Stimuli Pattern on YouTube QoE %X Video streaming over wireless broadband is currently re- sponsible for half of the world-wide mobile data traffic and its share is expected to even further increase. Therefore, mobile operators need to understand how Quality of Ex- perience (QoE) of mobile video streaming is impacted by through the network delivery. Due to HTTP video stream- ing used by video portals like YouTube or NetFlix, problems or insufficient resources in the networks manifest as stalling events during service consumption on an end user device. In this paper, we discuss the challenges for QoE monitoring for HTTP-based mobile video regarding three aspects. First, the impact of different patterns in terms of stalling event frequency and length on QoE is quantified on behalf of a study on YouTube. Second, we evaluate predictive power of aggregate measures like total stalling time. Third, we discuss the resulting consequences and challenges for mobile video QoE modeling, monitoring and provisioning.
• Video Quality Monitoring based on Precomputed Frame Distortions. Klein, Dominik; Zinner, Thomas; Lange, Stanislav; Singeorzan, Vlad; Schmid, Matthias. In IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan). Ghent, Belgium, 2013.
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  In the past decade, video streaming has taken over a large part of the current Internet traffic and more and more TV broadcasters and network providers extend their portfolio of video streaming services. With the growing expectations of video consumers with respect to the service quality, monitoring is an important aspect for network providers to detect possible performance problems or high network load. In parallel, emerging technologies like software defined networking or network virtualization introduce support for specialized networks which allow enhanced functionality in the network. This development enables more sophisticated monitoring techniques in the specialized networks which use knowledge about the video content to better predict the service quality at consumers. In this work, we present a content-aware SSIM-based monitoring technique and compare it with the current state-of-the art which infers the service quality from the monitored packet loss. We further show how network conditions like packet loss or bursts influence the two different monitoring techniques.

  @inproceedings{info3-inproceedings-2013-464, abstract = {In the past decade, video streaming has taken over a large part of the current Internet traffic and more and more TV broadcasters and network providers extend their portfolio of video streaming services. With the growing expectations of video consumers with respect to the service quality, monitoring is an important aspect for network providers to detect possible performance problems or high network load. In parallel, emerging technologies like software defined networking or network virtualization introduce support for specialized networks which allow enhanced functionality in the network. This development enables more sophisticated monitoring techniques in the specialized networks which use knowledge about the video content to better predict the service quality at consumers. In this work, we present a content-aware SSIM-based monitoring technique and compare it with the current state-of-the art which infers the service quality from the monitored packet loss. We further show how network conditions like packet loss or bursts influence the two different monitoring techniques.}, address = {Ghent, Belgium}, author = {Klein, Dominik and Zinner, Thomas and Lange, Stanislav and Singeorzan, Vlad and Schmid, Matthias}, booktitle = {IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Video Quality Monitoring based on Precomputed Frame Distortions}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-464 %A Klein, Dominik %A Zinner, Thomas %A Lange, Stanislav %A Singeorzan, Vlad %A Schmid, Matthias %B IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan) %C Ghent, Belgium %D 2013 %T Video Quality Monitoring based on Precomputed Frame Distortions %X In the past decade, video streaming has taken over a large part of the current Internet traffic and more and more TV broadcasters and network providers extend their portfolio of video streaming services. With the growing expectations of video consumers with respect to the service quality, monitoring is an important aspect for network providers to detect possible performance problems or high network load. In parallel, emerging technologies like software defined networking or network virtualization introduce support for specialized networks which allow enhanced functionality in the network. This development enables more sophisticated monitoring techniques in the specialized networks which use knowledge about the video content to better predict the service quality at consumers. In this work, we present a content-aware SSIM-based monitoring technique and compare it with the current state-of-the art which infers the service quality from the monitored packet loss. We further show how network conditions like packet loss or bursts influence the two different monitoring techniques.
• Monitoring YouTube QoE: Is Your Mobile Network Delivering the Right Experience to your Customers?. Casas, Pedro; Schatz, Raimund; Hoßfeld, Tobias. In 2013 IEEE Wireless Communications and Networking Conference (WCNC 2013). Shanghai, China, 2013.
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  YouTube, the monster application of today’s Internet, is changing the way ISPs and network operators manage quality monitoring and provisioning on their IP networks. YouTube is currently the most consumed Internet application, accounting for more than 30% of the overall Internet’s traffic worldwide. Coupling such an overwhelming traffic volume with the ever intensifying competition among ISPs is pushing operators to integrate Quality of Experience (QoE) paradigms into their traffic management systems. The need for automatic QoE assessment solutions becomes even more critical in mobile broadband networks, where over-provisioning solutions can not be foreseen and bad user experience translates into churning clients. This paper presents a complete study on the problem of YouTube Quality of Experience monitoring and assessment in mobile networks. The paper considers not only the QoE analysis, modeling and assessment based on real users’ experience, but also the passive monitoring of the quality provided by the ISP to its end-customers in a large mobile broadband network.

  @inproceedings{info3-inproceedings-2013-458, abstract = {YouTube, the monster application of today’s Internet, is changing the way ISPs and network operators manage quality monitoring and provisioning on their IP networks. YouTube is currently the most consumed Internet application, accounting for more than 30% of the overall Internet’s traffic worldwide. Coupling such an overwhelming traffic volume with the ever intensifying competition among ISPs is pushing operators to integrate Quality of Experience (QoE) paradigms into their traffic management systems. The need for automatic QoE assessment solutions becomes even more critical in mobile broadband networks, where over-provisioning solutions can not be foreseen and bad user experience translates into churning clients. This paper presents a complete study on the problem of YouTube Quality of Experience monitoring and assessment in mobile networks. The paper considers not only the QoE analysis, modeling and assessment based on real users’ experience, but also the passive monitoring of the quality provided by the ISP to its end-customers in a large mobile broadband network.}, address = {Shanghai, China}, author = {Casas, Pedro and Schatz, Raimund and Hoßfeld, Tobias}, booktitle = {2013 IEEE Wireless Communications and Networking Conference (WCNC 2013)}, keywords = {demobenefit}, month = {04}, title = {Monitoring YouTube QoE: Is Your Mobile Network Delivering the Right Experience to your Customers?}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-458 %A Casas, Pedro %A Schatz, Raimund %A Hoßfeld, Tobias %B 2013 IEEE Wireless Communications and Networking Conference (WCNC 2013) %C Shanghai, China %D 2013 %T Monitoring YouTube QoE: Is Your Mobile Network Delivering the Right Experience to your Customers? %X YouTube, the monster application of today’s Internet, is changing the way ISPs and network operators manage quality monitoring and provisioning on their IP networks. YouTube is currently the most consumed Internet application, accounting for more than 30% of the overall Internet’s traffic worldwide. Coupling such an overwhelming traffic volume with the ever intensifying competition among ISPs is pushing operators to integrate Quality of Experience (QoE) paradigms into their traffic management systems. The need for automatic QoE assessment solutions becomes even more critical in mobile broadband networks, where over-provisioning solutions can not be foreseen and bad user experience translates into churning clients. This paper presents a complete study on the problem of YouTube Quality of Experience monitoring and assessment in mobile networks. The paper considers not only the QoE analysis, modeling and assessment based on real users’ experience, but also the passive monitoring of the quality provided by the ISP to its end-customers in a large mobile broadband network.
• Entropy Production in Stationary Social Networks. Hinrichsen, Haye; Hoßfeld, Tobias; Hirth, Matthias; Tran-Gia, Phuoc. In 4th Workshop on Complex Networks (CompleNet 2013). Berlin, Germany, 2013.
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  Completing their initial phase of rapid growth social networks are expected to reach a plateau from where on they are in a statistically stationary state. Such stationary conditions may have different dynamical properties. For example, if each message in a network is followed by a reply in opposite direction, the dynamics is locally balanced. Otherwise, if messages are ignored or forwarded to a different user, one may reach a stationary state with a directed flow of information. To distinguish between the two situations, we propose a quantity called *entropy production* that was introduced in statistical physics as a measure for non-vanishing probability currents in nonequilibrium stationary states. The proposed quantity closes a gap for characterizing social networks. As major contribution, we present a general scheme that allows one to measure the entropy production in arbitrary social networks in which individuals are interacting with each other, e.g. by exchanging messages. The scheme is then applied for a specific example of the R mailing list.

  @inproceedings{info3-inproceedings-2013-457, abstract = {Completing their initial phase of rapid growth social networks are expected to reach a plateau from where on they are in a statistically stationary state. Such stationary conditions may have different dynamical properties. For example, if each message in a network is followed by a reply in opposite direction, the dynamics is locally balanced. Otherwise, if messages are ignored or forwarded to a different user, one may reach a stationary state with a directed flow of information. To distinguish between the two situations, we propose a quantity called *entropy production* that was introduced in statistical physics as a measure for non-vanishing probability currents in nonequilibrium stationary states. The proposed quantity closes a gap for characterizing social networks. As major contribution, we present a general scheme that allows one to measure the entropy production in arbitrary social networks in which individuals are interacting with each other, e.g. by exchanging messages. The scheme is then applied for a specific example of the R mailing list.}, address = {Berlin, Germany}, author = {Hinrichsen, Haye and Hoßfeld, Tobias and Hirth, Matthias and Tran-Gia, Phuoc}, booktitle = {4th Workshop on Complex Networks (CompleNet 2013)}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Entropy Production in Stationary Social Networks}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-457 %A Hinrichsen, Haye %A Hoßfeld, Tobias %A Hirth, Matthias %A Tran-Gia, Phuoc %B 4th Workshop on Complex Networks (CompleNet 2013) %C Berlin, Germany %D 2013 %T Entropy Production in Stationary Social Networks %X Completing their initial phase of rapid growth social networks are expected to reach a plateau from where on they are in a statistically stationary state. Such stationary conditions may have different dynamical properties. For example, if each message in a network is followed by a reply in opposite direction, the dynamics is locally balanced. Otherwise, if messages are ignored or forwarded to a different user, one may reach a stationary state with a directed flow of information. To distinguish between the two situations, we propose a quantity called *entropy production* that was introduced in statistical physics as a measure for non-vanishing probability currents in nonequilibrium stationary states. The proposed quantity closes a gap for characterizing social networks. As major contribution, we present a general scheme that allows one to measure the entropy production in arbitrary social networks in which individuals are interacting with each other, e.g. by exchanging messages. The scheme is then applied for a specific example of the R mailing list.
• Using Optimized Virtual Network Embedding for Network Dimensioning. Inführ, Johannes; Stezenbach, David; Hartmann, Matthias; Tutschku, Kurt; Raidl, Günther R. In IEEE Conference on Networked Systems (NetSys) 2013. Stuttgart, Germany, 2013.
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  Virtual Network Embedding will be one of the key concepts of the Future Internet. For an ISP it is important to know how many additional Virtual Networks (VNs) of a specific application (e.g. web, streaming, P2P, and VoIP) are mappable into the current resource substrate with a certain probability. In this work we calculate this probability with our embedding algorithm which enables us to consider side effects based on remapping of VNs (e.g. due to reduced link delay). Our results show that minimal extra resources can significantly increase embedding probability of additional VNs.

  @inproceedings{info3-inproceedings-2013-460, abstract = {Virtual Network Embedding will be one of the key concepts of the Future Internet. For an ISP it is important to know how many additional Virtual Networks (VNs) of a specific application (e.g. web, streaming, P2P, and VoIP) are mappable into the current resource substrate with a certain probability. In this work we calculate this probability with our embedding algorithm which enables us to consider side effects based on remapping of VNs (e.g. due to reduced link delay). Our results show that minimal extra resources can significantly increase embedding probability of additional VNs.}, address = {Stuttgart, Germany}, author = {Inführ, Johannes and Stezenbach, David and Hartmann, Matthias and Tutschku, Kurt and Raidl, Günther R.}, booktitle = {IEEE Conference on Networked Systems (NetSys) 2013}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Using Optimized Virtual Network Embedding for Network Dimensioning}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-460 %A Inführ, Johannes %A Stezenbach, David %A Hartmann, Matthias %A Tutschku, Kurt %A Raidl, Günther R. %B IEEE Conference on Networked Systems (NetSys) 2013 %C Stuttgart, Germany %D 2013 %T Using Optimized Virtual Network Embedding for Network Dimensioning %X Virtual Network Embedding will be one of the key concepts of the Future Internet. For an ISP it is important to know how many additional Virtual Networks (VNs) of a specific application (e.g. web, streaming, P2P, and VoIP) are mappable into the current resource substrate with a certain probability. In this work we calculate this probability with our embedding algorithm which enables us to consider side effects based on remapping of VNs (e.g. due to reduced link delay). Our results show that minimal extra resources can significantly increase embedding probability of additional VNs.
• An OpenFlow Extension for the OMNeT++ INET Framework. Klein, Dominik; Jarschel, Michael. In 6th International Workshop on OMNeT++. Cannes, France, 2013.
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  Software Defined Networking (SDN) is a new paradigm for communication networks which separates the control plane from the data plane of forwarding elements. This way, SDN constitutes a flexible architecture that allows quick and easy configuration of network devices. This ability is particularly useful when networks have to be adapted to changing traffic volumes of different applications running on the network. OpenFlow is currently the most prominent approach which implements the SDN concept and offers a high flexibility in the routing of network flows. In this paper, we describe the implementation of our model of the OpenFlow system in the INET framework for OMNeT++. We present performance results to show the correctness of our model. As a first application, we use the simulation model to assess the round-trip-times in a theoretical OpenFlow deployment in a real topology of a North-American Testbed.

  @inproceedings{info3-inproceedings-2013-461, abstract = {Software Defined Networking (SDN) is a new paradigm for communication networks which separates the control plane from the data plane of forwarding elements. This way, SDN constitutes a flexible architecture that allows quick and easy configuration of network devices. This ability is particularly useful when networks have to be adapted to changing traffic volumes of different applications running on the network. OpenFlow is currently the most prominent approach which implements the SDN concept and offers a high flexibility in the routing of network flows. In this paper, we describe the implementation of our model of the OpenFlow system in the INET framework for OMNeT++. We present performance results to show the correctness of our model. As a first application, we use the simulation model to assess the round-trip-times in a theoretical OpenFlow deployment in a real topology of a North-American Testbed.}, address = {Cannes, France}, author = {Klein, Dominik and Jarschel, Michael}, booktitle = {6th International Workshop on OMNeT++}, keywords = {openflow}, month = {03}, title = {An OpenFlow Extension for the OMNeT++ INET Framework}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-461 %A Klein, Dominik %A Jarschel, Michael %B 6th International Workshop on OMNeT++ %C Cannes, France %D 2013 %T An OpenFlow Extension for the OMNeT++ INET Framework %X Software Defined Networking (SDN) is a new paradigm for communication networks which separates the control plane from the data plane of forwarding elements. This way, SDN constitutes a flexible architecture that allows quick and easy configuration of network devices. This ability is particularly useful when networks have to be adapted to changing traffic volumes of different applications running on the network. OpenFlow is currently the most prominent approach which implements the SDN concept and offers a high flexibility in the routing of network flows. In this paper, we describe the implementation of our model of the OpenFlow system in the INET framework for OMNeT++. We present performance results to show the correctness of our model. As a first application, we use the simulation model to assess the round-trip-times in a theoretical OpenFlow deployment in a real topology of a North-American Testbed.
• Resilience in Enterprise Social Networks. Burger, Valentin; Hoßfeld, Tobias; Garcia, David; Seufert, Michael; Scholtes, Ingo; Hock, David. In Workshop Sozioinformatik 2013. Koblenz, Germany, 2013.
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  The goal of human resource management is to ensure an effective company environment. Crucial for a good corporate culture is a comfortable atmosphere and positive social relationships between the employees. The interactions of the people and groups working in the company define their relationships and are reflected in the company's social network. Projections of such networks are Enterprise Social Networks which are more and more integrated in companies. These social networks can be a powerful tool to analyse the structure of a company and indicate potential problems. This extended abstract poses research questions to identify and quantify mechanisms that have an impact on the social network of a company to ensure resilience. To address these questions we make assumptions based on real-world observations for a subsequent model.

  @inproceedings{info3-inproceedings-2013-473, abstract = {The goal of human resource management is to ensure an effective company environment. Crucial for a good corporate culture is a comfortable atmosphere and positive social relationships between the employees. The interactions of the people and groups working in the company define their relationships and are reflected in the company's social network. Projections of such networks are Enterprise Social Networks which are more and more integrated in companies. These social networks can be a powerful tool to analyse the structure of a company and indicate potential problems. This extended abstract poses research questions to identify and quantify mechanisms that have an impact on the social network of a company to ensure resilience. To address these questions we make assumptions based on real-world observations for a subsequent model.}, address = {Koblenz, Germany}, author = {Burger, Valentin and Hoßfeld, Tobias and Garcia, David and Seufert, Michael and Scholtes, Ingo and Hock, David}, booktitle = {Workshop Sozioinformatik 2013}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Resilience in Enterprise Social Networks}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-473 %A Burger, Valentin %A Hoßfeld, Tobias %A Garcia, David %A Seufert, Michael %A Scholtes, Ingo %A Hock, David %B Workshop Sozioinformatik 2013 %C Koblenz, Germany %D 2013 %T Resilience in Enterprise Social Networks %X The goal of human resource management is to ensure an effective company environment. Crucial for a good corporate culture is a comfortable atmosphere and positive social relationships between the employees. The interactions of the people and groups working in the company define their relationships and are reflected in the company's social network. Projections of such networks are Enterprise Social Networks which are more and more integrated in companies. These social networks can be a powerful tool to analyse the structure of a company and indicate potential problems. This extended abstract poses research questions to identify and quantify mechanisms that have an impact on the social network of a company to ensure resilience. To address these questions we make assumptions based on real-world observations for a subsequent model.
• Smart-Phone Energy Consumption Vs. 3G Signaling Load: The Influence of Application Traffic Patterns. Schwartz, Christian; Lehrieder, Frank; Wamser, Florian; Hoßfeld, Tobias; Tran-Gia, Phuoc. In Tyrrhenian International Workshop 2013 on Digital Communications: Green ICT. Genova, Italy, 2013.
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  The high signaling load in today’s UMTS networks has recently lead to severe problems and network outages of several hours, so called Signaling Storms. The reason is that cer- tain network access patterns of popular smart-phone applications trigger frequent connection re-establishments, which are signaled to the network via the radio resource control (RRC) protocol. As a consequence of the network agnostic implementation of smart- phone applications, entities of the mobile network operator may experience overload, while energy consumption at the smart- phones is mutually determined. The aim of this work is to study the impact of traffic charac- teristics on the power consumption of the smart-phone and the signaling messages in the mobile network. For that purpose, we first develop a simple model for the RRC states of a smart-phone. Second, we estimate the resulting power drain and the signalling traffic of the smart-phone. Then, we investigate the applicability of our model by comparing analytical with simulation results for real-world smart-phone traffic measurements. Finally, we evaluate the effect of network parameter optimization on traffic with different statistical characteristics. Our counter-intuitive results show that in particular bursty traffic patterns are suitable for UMTS networks while periodic patterns may cause increased power consumption and signaling overload – in contrast to classical queueing systems.

  @inproceedings{info3-inproceedings-2013-481, abstract = {The high signaling load in today’s UMTS networks has recently lead to severe problems and network outages of several hours, so called Signaling Storms. The reason is that cer- tain network access patterns of popular smart-phone applications trigger frequent connection re-establishments, which are signaled to the network via the radio resource control (RRC) protocol. As a consequence of the network agnostic implementation of smart- phone applications, entities of the mobile network operator may experience overload, while energy consumption at the smart- phones is mutually determined. The aim of this work is to study the impact of traffic charac- teristics on the power consumption of the smart-phone and the signaling messages in the mobile network. For that purpose, we first develop a simple model for the RRC states of a smart-phone. Second, we estimate the resulting power drain and the signalling traffic of the smart-phone. Then, we investigate the applicability of our model by comparing analytical with simulation results for real-world smart-phone traffic measurements. Finally, we evaluate the effect of network parameter optimization on traffic with different statistical characteristics. Our counter-intuitive results show that in particular bursty traffic patterns are suitable for UMTS networks while periodic patterns may cause increased power consumption and signaling overload – in contrast to classical queueing systems.}, address = {Genova, Italy}, author = {Schwartz, Christian and Lehrieder, Frank and Wamser, Florian and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {Tyrrhenian International Workshop 2013 on Digital Communications: Green ICT}, keywords = {oekonet}, month = {09}, title = {Smart-Phone Energy Consumption Vs. 3G Signaling Load: The Influence of Application Traffic Patterns}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-481 %A Schwartz, Christian %A Lehrieder, Frank %A Wamser, Florian %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B Tyrrhenian International Workshop 2013 on Digital Communications: Green ICT %C Genova, Italy %D 2013 %T Smart-Phone Energy Consumption Vs. 3G Signaling Load: The Influence of Application Traffic Patterns %X The high signaling load in today’s UMTS networks has recently lead to severe problems and network outages of several hours, so called Signaling Storms. The reason is that cer- tain network access patterns of popular smart-phone applications trigger frequent connection re-establishments, which are signaled to the network via the radio resource control (RRC) protocol. As a consequence of the network agnostic implementation of smart- phone applications, entities of the mobile network operator may experience overload, while energy consumption at the smart- phones is mutually determined. The aim of this work is to study the impact of traffic charac- teristics on the power consumption of the smart-phone and the signaling messages in the mobile network. For that purpose, we first develop a simple model for the RRC states of a smart-phone. Second, we estimate the resulting power drain and the signalling traffic of the smart-phone. Then, we investigate the applicability of our model by comparing analytical with simulation results for real-world smart-phone traffic measurements. Finally, we evaluate the effect of network parameter optimization on traffic with different statistical characteristics. Our counter-intuitive results show that in particular bursty traffic patterns are suitable for UMTS networks while periodic patterns may cause increased power consumption and signaling overload – in contrast to classical queueing systems.
• Investigation of Different Approaches for QoE-Oriented Scheduling in OFDMA Networks. Wamser, Florian; Deschner, Sebastian; Zinner, Thomas; Tran-Gia, Phuoc. In Mobile Networks and Management, Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering Volume 125, pp. 172–187. Cork, Irland, 2013.
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  QoE- and application-aware scheduling is a new paradigm for mobile communication networks. It aims at making better use of network resources with respect to the perceived quality of the users. To achieve this, it specifies an interaction between application and networking layers. Previous work has shown that such a resource management is possible by the weighting of applications and the definition of key quality indicators. However, quantification of the benefits and the impact on the application itself is hardly studied, since it requires precise modeling of both the data transmission in the mobile network as well as the application itself. In this paper the influence of different cross-layer scheduling heuristics on the application is examined for the air interface of LTE mobile networks. For this, not only the physical data transmission but also the application behavior is simulated in detail for Skype, YouTube, web browsing, and downloads. For each application quality indicators are defined that provide information on the current performance of the application. The investigated scheduling approaches take into account detailed application information of different levels like the application type, the current status of the application, or the ability of an application to adapt to the network situation.

  @inproceedings{info3-inproceedings-2013-478, abstract = {QoE- and application-aware scheduling is a new paradigm for mobile communication networks. It aims at making better use of network resources with respect to the perceived quality of the users. To achieve this, it specifies an interaction between application and networking layers. Previous work has shown that such a resource management is possible by the weighting of applications and the definition of key quality indicators. However, quantification of the benefits and the impact on the application itself is hardly studied, since it requires precise modeling of both the data transmission in the mobile network as well as the application itself. In this paper the influence of different cross-layer scheduling heuristics on the application is examined for the air interface of LTE mobile networks. For this, not only the physical data transmission but also the application behavior is simulated in detail for Skype, YouTube, web browsing, and downloads. For each application quality indicators are defined that provide information on the current performance of the application. The investigated scheduling approaches take into account detailed application information of different levels like the application type, the current status of the application, or the ability of an application to adapt to the network situation.}, address = {Cork, Irland}, author = {Wamser, Florian and Deschner, Sebastian and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {Mobile Networks and Management, Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering Volume 125}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {172-187}, title = {Investigation of Different Approaches for QoE-Oriented Scheduling in OFDMA Networks}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-478 %A Wamser, Florian %A Deschner, Sebastian %A Zinner, Thomas %A Tran-Gia, Phuoc %B Mobile Networks and Management, Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering Volume 125 %C Cork, Irland %D 2013 %P 172-187 %T Investigation of Different Approaches for QoE-Oriented Scheduling in OFDMA Networks %X QoE- and application-aware scheduling is a new paradigm for mobile communication networks. It aims at making better use of network resources with respect to the perceived quality of the users. To achieve this, it specifies an interaction between application and networking layers. Previous work has shown that such a resource management is possible by the weighting of applications and the definition of key quality indicators. However, quantification of the benefits and the impact on the application itself is hardly studied, since it requires precise modeling of both the data transmission in the mobile network as well as the application itself. In this paper the influence of different cross-layer scheduling heuristics on the application is examined for the air interface of LTE mobile networks. For this, not only the physical data transmission but also the application behavior is simulated in detail for Skype, YouTube, web browsing, and downloads. For each application quality indicators are defined that provide information on the current performance of the application. The investigated scheduling approaches take into account detailed application information of different levels like the application type, the current status of the application, or the ability of an application to adapt to the network situation.
• Crowdsourcing-based multimedia subjective evaluations: a case study on image recognizability and aesthetic appeal. Redi, Judith; Hoßfeld, Tobias; Korshunov, Pavel; Mazza, Filippo; Povoa, Isabel; Keimel, Christian. In ACM CrowdMM 2013. Barcelona, Spain, 2013.
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  Crowdsourcing is a popular approach for employing people online to perform short and simple tasks. Research on Quality of Experience (QoE), which relies on subjective evaluations of media, could especially benefit from it. One question related to QoE, which is as well important for image retrieval and summarization systems, concerns modelling and quantifying the subjective notions of `beauty' (aesthetic appeal) and `something well-known' (content recognizability). Since both notions may be subject to cultural and social effects, crowdsourcing, which allows to employ worldwide, can be a great tool for carrying on subjective studies in a time and cost-effective way. On the other hand, the crowdsourcing environment does not allow for the degree of excperimental control which is necessary to guarantee reliable subjective data. In this paper, we evaluate aesthetic appeal and recognizability of images using a crowdsourcing platform and compare the outcomes with more conventional evaluations conducted in a controlled lab environment. We find high correlation between crowdsourcing and lab scores for recognizability but not for aesthetic appeal. The analysis of the results indicates possible causes for this, suggesting that crowdsourcing can be used for QoE subjective assessments as long as the workers' tasks are designed with extreme care to avoid misinterpretations and unreliability.

  @inproceedings{info3-inproceedings-2013-475, abstract = {Crowdsourcing is a popular approach for employing people online to perform short and simple tasks. Research on Quality of Experience (QoE), which relies on subjective evaluations of media, could especially benefit from it. One question related to QoE, which is as well important for image retrieval and summarization systems, concerns modelling and quantifying the subjective notions of `beauty' (aesthetic appeal) and `something well-known' (content recognizability). Since both notions may be subject to cultural and social effects, crowdsourcing, which allows to employ worldwide, can be a great tool for carrying on subjective studies in a time and cost-effective way. On the other hand, the crowdsourcing environment does not allow for the degree of excperimental control which is necessary to guarantee reliable subjective data. In this paper, we evaluate aesthetic appeal and recognizability of images using a crowdsourcing platform and compare the outcomes with more conventional evaluations conducted in a controlled lab environment. We find high correlation between crowdsourcing and lab scores for recognizability but not for aesthetic appeal. The analysis of the results indicates possible causes for this, suggesting that crowdsourcing can be used for QoE subjective assessments as long as the workers' tasks are designed with extreme care to avoid misinterpretations and unreliability.}, address = {Barcelona, Spain}, author = {Redi, Judith and Hoßfeld, Tobias and Korshunov, Pavel and Mazza, Filippo and Povoa, Isabel and Keimel, Christian}, booktitle = {ACM CrowdMM 2013}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Crowdsourcing-based multimedia subjective evaluations: a case study on image recognizability and aesthetic appeal}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-475 %A Redi, Judith %A Hoßfeld, Tobias %A Korshunov, Pavel %A Mazza, Filippo %A Povoa, Isabel %A Keimel, Christian %B ACM CrowdMM 2013 %C Barcelona, Spain %D 2013 %T Crowdsourcing-based multimedia subjective evaluations: a case study on image recognizability and aesthetic appeal %X Crowdsourcing is a popular approach for employing people online to perform short and simple tasks. Research on Quality of Experience (QoE), which relies on subjective evaluations of media, could especially benefit from it. One question related to QoE, which is as well important for image retrieval and summarization systems, concerns modelling and quantifying the subjective notions of `beauty' (aesthetic appeal) and `something well-known' (content recognizability). Since both notions may be subject to cultural and social effects, crowdsourcing, which allows to employ worldwide, can be a great tool for carrying on subjective studies in a time and cost-effective way. On the other hand, the crowdsourcing environment does not allow for the degree of excperimental control which is necessary to guarantee reliable subjective data. In this paper, we evaluate aesthetic appeal and recognizability of images using a crowdsourcing platform and compare the outcomes with more conventional evaluations conducted in a controlled lab environment. We find high correlation between crowdsourcing and lab scores for recognizability but not for aesthetic appeal. The analysis of the results indicates possible causes for this, suggesting that crowdsourcing can be used for QoE subjective assessments as long as the workers' tasks are designed with extreme care to avoid misinterpretations and unreliability.
• Increasing Payments in Crowdsourcing: Don’t look a gift horse in the mouth. Varela, Martin; Mäki, Toni; Skorin-Kapov, Lea; Hoßfeld, Tobias. In 4th International Workshop on Perceptual Quality of Systems (PQS 2013). Vienna, Austria, 2013.
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  A commonly cited maxim states that 'you get what you pay for'. Implicit in it is the idea that there is a strong correlation between the price paid for something, and its quality. In this paper, we examine whether that applies to crowdsourcing for QoE experiments, and if so, how. As part of a large-scale Web QoE experiment, we conducted two crowdsourced campaigns to try and understand the influence of certain website design parameters related to typography and color on the overall visual appeal of the site. The second campaign was set up to pay three times the reward of the first one. We analyze the impact of payment on a number of parameters, including ratio of reliable users and obtained MOS values, and provide recommendations for QoE modeling.

  @inproceedings{info3-inproceedings-2013-470, abstract = {A commonly cited maxim states that 'you get what you pay for'. Implicit in it is the idea that there is a strong correlation between the price paid for something, and its quality. In this paper, we examine whether that applies to crowdsourcing for QoE experiments, and if so, how. As part of a large-scale Web QoE experiment, we conducted two crowdsourced campaigns to try and understand the influence of certain website design parameters related to typography and color on the overall visual appeal of the site. The second campaign was set up to pay three times the reward of the first one. We analyze the impact of payment on a number of parameters, including ratio of reliable users and obtained MOS values, and provide recommendations for QoE modeling.}, address = {Vienna, Austria}, author = {Varela, Martin and Mäki, Toni and Skorin-Kapov, Lea and Hoßfeld, Tobias}, booktitle = {4th International Workshop on Perceptual Quality of Systems (PQS 2013)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Increasing Payments in Crowdsourcing: Don't look a gift horse in the mouth}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-470 %A Varela, Martin %A Mäki, Toni %A Skorin-Kapov, Lea %A Hoßfeld, Tobias %B 4th International Workshop on Perceptual Quality of Systems (PQS 2013) %C Vienna, Austria %D 2013 %T Increasing Payments in Crowdsourcing: Don't look a gift horse in the mouth %X A commonly cited maxim states that 'you get what you pay for'. Implicit in it is the idea that there is a strong correlation between the price paid for something, and its quality. In this paper, we examine whether that applies to crowdsourcing for QoE experiments, and if so, how. As part of a large-scale Web QoE experiment, we conducted two crowdsourced campaigns to try and understand the influence of certain website design parameters related to typography and color on the overall visual appeal of the site. The second campaign was set up to pay three times the reward of the first one. We analyze the impact of payment on a number of parameters, including ratio of reliable users and obtained MOS values, and provide recommendations for QoE modeling.
• On the Accuracy of Leveraging SDN for Passive Network Measurements. Jarschel, Michael; Zinner, Thomas; Höhn, Thomas; Tran-Gia, Phuoc. In Australasian Telecommunication Networks & Applications Conference (ATNAC 2013). Christchurch, New Zealand, 2013.
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  Network Measurement has emerged as one promising field of application for Software Defined Networking. The reason for this is that the logically centralized control plane of an SDN network inherently has to aggregate network state information in order to function. This circumstance can be leveraged for network measurements at the SDN controller without the need for additional equipment or active – and possibly disruptive – measurements in the network itself. However, the accuracy and potential resource overhead of this approach has not been discussed. In this paper we compare an SDN-based solution to actual traffic measurements in order to determine its accuracy and resource demand by performing tests in an OpenFlow testbed.

  @inproceedings{info3-inproceedings-2013-480, abstract = {Network Measurement has emerged as one promising field of application for Software Defined Networking. The reason for this is that the logically centralized control plane of an SDN network inherently has to aggregate network state information in order to function. This circumstance can be leveraged for network measurements at the SDN controller without the need for additional equipment or active – and possibly disruptive – measurements in the network itself. However, the accuracy and potential resource overhead of this approach has not been discussed. In this paper we compare an SDN-based solution to actual traffic measurements in order to determine its accuracy and resource demand by performing tests in an OpenFlow testbed.}, address = {Christchurch, New Zealand}, author = {Jarschel, Michael and Zinner, Thomas and Höhn, Thomas and Tran-Gia, Phuoc}, booktitle = {Australasian Telecommunication Networks & Applications Conference (ATNAC 2013)}, keywords = {sys:hidden:inproceedings}, month = 11, title = {On the Accuracy of Leveraging SDN for Passive Network Measurements}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-480 %A Jarschel, Michael %A Zinner, Thomas %A Höhn, Thomas %A Tran-Gia, Phuoc %B Australasian Telecommunication Networks & Applications Conference (ATNAC 2013) %C Christchurch, New Zealand %D 2013 %T On the Accuracy of Leveraging SDN for Passive Network Measurements %X Network Measurement has emerged as one promising field of application for Software Defined Networking. The reason for this is that the logically centralized control plane of an SDN network inherently has to aggregate network state information in order to function. This circumstance can be leveraged for network measurements at the SDN controller without the need for additional equipment or active – and possibly disruptive – measurements in the network itself. However, the accuracy and potential resource overhead of this approach has not been discussed. In this paper we compare an SDN-based solution to actual traffic measurements in order to determine its accuracy and resource demand by performing tests in an OpenFlow testbed.
• Trade-Offs for Video-Providers in LTE Networks: Smartphone Energy Consumption Vs Wasted Traffic. Schwartz, Christian; Scheib, Marc; Hoßfeld, Tobias; Tran-Gia, Phuoc; Manuel Gimenez-Guzman, Jose. In 22nd International Teletraffic Congress Specialist Seminar on Energy Efficient and Green Networking. Christchurch, New Zealand, 2013.
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  Long Term Evolution (LTE) networks provide broadband Internet access to mobile users. One of the main use cases for LTE is a mobile video. When selecting a video transmis- sion mechanism, a video provider has to consider different and orthogonal metrics. The consumer expects a high video Quality of Experience (QoE) and a low energy consumption during download and playback. The video provider is interested in minimizing its resources and corresponding costs, like bandwidth and wasted traffic. Wasted traffic occurs if a user aborts and additional video data is already downloaded but not played out, consuming resources unnecessarily. This raises the questions 1) how a video provider delivers the video contents while reducing the operational costs and satisfying the customers demands 2) what is the influence of the customer abort behaviour. To answer these questions, we first study the influence of mechanism selection on energy consumption and wasted traffic. Second, we show that the different user models do not influence the wasted traffic significantly. Finally, we provide parameter se- lection guidelines for the Streaming mechanism, which are shown to satisfy better both the requirements of the video provider as well as those of the customer, to achieve Pareto optimal results with regard to the smartphone energy consumption and wasted traffic.

  @inproceedings{info3-inproceedings-2013-482, abstract = {Long Term Evolution (LTE) networks provide broadband Internet access to mobile users. One of the main use cases for LTE is a mobile video. When selecting a video transmis- sion mechanism, a video provider has to consider different and orthogonal metrics. The consumer expects a high video Quality of Experience (QoE) and a low energy consumption during download and playback. The video provider is interested in minimizing its resources and corresponding costs, like bandwidth and wasted traffic. Wasted traffic occurs if a user aborts and additional video data is already downloaded but not played out, consuming resources unnecessarily. This raises the questions 1) how a video provider delivers the video contents while reducing the operational costs and satisfying the customers demands 2) what is the influence of the customer abort behaviour. To answer these questions, we first study the influence of mechanism selection on energy consumption and wasted traffic. Second, we show that the different user models do not influence the wasted traffic significantly. Finally, we provide parameter se- lection guidelines for the Streaming mechanism, which are shown to satisfy better both the requirements of the video provider as well as those of the customer, to achieve Pareto optimal results with regard to the smartphone energy consumption and wasted traffic.}, address = {Christchurch, New Zealand}, author = {Schwartz, Christian and Scheib, Marc and Hoßfeld, Tobias and Tran-Gia, Phuoc and Manuel Gimenez-Guzman, Jose}, booktitle = {22nd International Teletraffic Congress Specialist Seminar on Energy Efficient and Green Networking}, keywords = {smartenit}, month = 11, title = {Trade-Offs for Video-Providers in LTE Networks: Smartphone Energy Consumption Vs Wasted Traffic}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-482 %A Schwartz, Christian %A Scheib, Marc %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %A Manuel Gimenez-Guzman, Jose %B 22nd International Teletraffic Congress Specialist Seminar on Energy Efficient and Green Networking %C Christchurch, New Zealand %D 2013 %T Trade-Offs for Video-Providers in LTE Networks: Smartphone Energy Consumption Vs Wasted Traffic %X Long Term Evolution (LTE) networks provide broadband Internet access to mobile users. One of the main use cases for LTE is a mobile video. When selecting a video transmis- sion mechanism, a video provider has to consider different and orthogonal metrics. The consumer expects a high video Quality of Experience (QoE) and a low energy consumption during download and playback. The video provider is interested in minimizing its resources and corresponding costs, like bandwidth and wasted traffic. Wasted traffic occurs if a user aborts and additional video data is already downloaded but not played out, consuming resources unnecessarily. This raises the questions 1) how a video provider delivers the video contents while reducing the operational costs and satisfying the customers demands 2) what is the influence of the customer abort behaviour. To answer these questions, we first study the influence of mechanism selection on energy consumption and wasted traffic. Second, we show that the different user models do not influence the wasted traffic significantly. Finally, we provide parameter se- lection guidelines for the Streaming mechanism, which are shown to satisfy better both the requirements of the video provider as well as those of the customer, to achieve Pareto optimal results with regard to the smartphone energy consumption and wasted traffic.
• SDN-based Application-Aware Networking on the Example of YouTube Video Streaming. Jarschel, Michael; Wamser, Florian; Höhn, Thomas; Zinner, Thomas; Tran-Gia, Phuoc. In 2nd European Workshop on Software Defined Networks (EWSDN 2013). Berlin, Germany, 2013.
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  Application-Aware Networking is a promising approach to provide good application quality to users in scenarios with limited network resources, like today’s access networks. With SDN, a particularly interesting method to enable flowbased traffic management in networks has become available. In this work we take a look at how a specific application, i.e., YouTube Streaming, can benefit from such an SDN-based Application-Aware Network. We implement and investigate an approach based on Deep Packet Inspection (DPI) and one based on direct information input from the application in an OpenFlow testbed in order to show, how these different types of application information can be exploited to enhance the Quality of Experience (QoE). Furthermore, we determine the overhead caused by each of the presented approaches.

  @inproceedings{info3-inproceedings-2013-477, abstract = {Application-Aware Networking is a promising approach to provide good application quality to users in scenarios with limited network resources, like today’s access networks. With SDN, a particularly interesting method to enable flowbased traffic management in networks has become available. In this work we take a look at how a specific application, i.e., YouTube Streaming, can benefit from such an SDN-based Application-Aware Network. We implement and investigate an approach based on Deep Packet Inspection (DPI) and one based on direct information input from the application in an OpenFlow testbed in order to show, how these different types of application information can be exploited to enhance the Quality of Experience (QoE). Furthermore, we determine the overhead caused by each of the presented approaches.}, address = {Berlin, Germany}, author = {Jarschel, Michael and Wamser, Florian and Höhn, Thomas and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {2nd European Workshop on Software Defined Networks (EWSDN 2013)}, keywords = {demobenefit}, month = 10, title = {SDN-based Application-Aware Networking on the Example of YouTube Video Streaming}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-477 %A Jarschel, Michael %A Wamser, Florian %A Höhn, Thomas %A Zinner, Thomas %A Tran-Gia, Phuoc %B 2nd European Workshop on Software Defined Networks (EWSDN 2013) %C Berlin, Germany %D 2013 %T SDN-based Application-Aware Networking on the Example of YouTube Video Streaming %X Application-Aware Networking is a promising approach to provide good application quality to users in scenarios with limited network resources, like today’s access networks. With SDN, a particularly interesting method to enable flowbased traffic management in networks has become available. In this work we take a look at how a specific application, i.e., YouTube Streaming, can benefit from such an SDN-based Application-Aware Network. We implement and investigate an approach based on Deep Packet Inspection (DPI) and one based on direct information input from the application in an OpenFlow testbed in order to show, how these different types of application information can be exploited to enhance the Quality of Experience (QoE). Furthermore, we determine the overhead caused by each of the presented approaches.
• HORST - Home Router Sharing based on Trust. Seufert, Michael; Burger, Valentin; Hoßfeld, Tobias. In Workshop on Social-aware Economic Traffic Management for Overlay and Cloud Applications (SETM). Zurich, Switzerland, 2013.
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  Today’s Internet services are increasingly accessed from mobile devices, thus being responsible for growing load in mobile networks. At the same time, more and more WiFi routers are deployed such that a dense coverage of WiFi is available. Results from different related works suggest that there is a high potential of reducing load on the mobile networks by offloading data to WiFi networks, thereby improving mobile users’ quality of experience (QoE) with Internet services. Additionally, the storage of the router could be used for content caching and delivery close to the end user, which is more energy efficient compared to classical content servers, and saves costs for network operators by reducing traffic between autonomous systems. Going one step beyond, we foresee that merging these approaches and augmenting them with social information from online social networks (OSNs) will result both in even less costs for network operators and increased QoE of end users. Therefore, we propose home router sharing based on trust (HORST) - a socially-aware traffic management solution which targets three popular use cases: data offloading to WiFi, content caching/prefetching, and content delivery.

  @inproceedings{info3-inproceedings-2013-476, abstract = {Today’s Internet services are increasingly accessed from mobile devices, thus being responsible for growing load in mobile networks. At the same time, more and more WiFi routers are deployed such that a dense coverage of WiFi is available. Results from different related works suggest that there is a high potential of reducing load on the mobile networks by offloading data to WiFi networks, thereby improving mobile users’ quality of experience (QoE) with Internet services. Additionally, the storage of the router could be used for content caching and delivery close to the end user, which is more energy efficient compared to classical content servers, and saves costs for network operators by reducing traffic between autonomous systems. Going one step beyond, we foresee that merging these approaches and augmenting them with social information from online social networks (OSNs) will result both in even less costs for network operators and increased QoE of end users. Therefore, we propose home router sharing based on trust (HORST) - a socially-aware traffic management solution which targets three popular use cases: data offloading to WiFi, content caching/prefetching, and content delivery.}, address = {Zurich, Switzerland}, author = {Seufert, Michael and Burger, Valentin and Hoßfeld, Tobias}, booktitle = {Workshop on Social-aware Economic Traffic Management for Overlay and Cloud Applications (SETM)}, keywords = {can}, month = 10, title = {HORST - Home Router Sharing based on Trust}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-476 %A Seufert, Michael %A Burger, Valentin %A Hoßfeld, Tobias %B Workshop on Social-aware Economic Traffic Management for Overlay and Cloud Applications (SETM) %C Zurich, Switzerland %D 2013 %T HORST - Home Router Sharing based on Trust %X Today’s Internet services are increasingly accessed from mobile devices, thus being responsible for growing load in mobile networks. At the same time, more and more WiFi routers are deployed such that a dense coverage of WiFi is available. Results from different related works suggest that there is a high potential of reducing load on the mobile networks by offloading data to WiFi networks, thereby improving mobile users’ quality of experience (QoE) with Internet services. Additionally, the storage of the router could be used for content caching and delivery close to the end user, which is more energy efficient compared to classical content servers, and saves costs for network operators by reducing traffic between autonomous systems. Going one step beyond, we foresee that merging these approaches and augmenting them with social information from online social networks (OSNs) will result both in even less costs for network operators and increased QoE of end users. Therefore, we propose home router sharing based on trust (HORST) - a socially-aware traffic management solution which targets three popular use cases: data offloading to WiFi, content caching/prefetching, and content delivery.
• Gamification Framework for Personalized Surveys on Relationships in Online Social Networks. Seufert, Michael; Lorey, Karl; Hirth, Matthias; Hoßfeld, Tobias. In 1st International Workshop on Crowdsourcing and Gamification in the Cloud (CGCloud). Dresden, Germany, 2013.
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  The estimation of psychological properties of relationships (e.g., popularity, influence, or trust) only from objective data in online social networks (OSNs) is a rather vague approach. A subjective assessment produces more accurate results, but it requires very complex and cumbersome surveys. The key contribution of this paper is a framework for personalized surveys on relationships in OSNs which follows a gamification approach. A game was developed and integrated into Facebook as an app, which makes it possible to obtain subjective ratings of users' relationships and objective data about the users, their interactions, and their social network. The combination of both subjective and objective data facilitates a deeper understanding of the psychological properties of relationships in OSNs, and lays the foundations for future research of subjective aspects within OSNs.

  @inproceedings{info3-inproceedings-2013-484, abstract = {The estimation of psychological properties of relationships (e.g., popularity, influence, or trust) only from objective data in online social networks (OSNs) is a rather vague approach. A subjective assessment produces more accurate results, but it requires very complex and cumbersome surveys. The key contribution of this paper is a framework for personalized surveys on relationships in OSNs which follows a gamification approach. A game was developed and integrated into Facebook as an app, which makes it possible to obtain subjective ratings of users' relationships and objective data about the users, their interactions, and their social network. The combination of both subjective and objective data facilitates a deeper understanding of the psychological properties of relationships in OSNs, and lays the foundations for future research of subjective aspects within OSNs.}, address = {Dresden, Germany}, author = {Seufert, Michael and Lorey, Karl and Hirth, Matthias and Hoßfeld, Tobias}, booktitle = {1st International Workshop on Crowdsourcing and Gamification in the Cloud (CGCloud)}, keywords = {smartenit}, month = 12, title = {Gamification Framework for Personalized Surveys on Relationships in Online Social Networks}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-484 %A Seufert, Michael %A Lorey, Karl %A Hirth, Matthias %A Hoßfeld, Tobias %B 1st International Workshop on Crowdsourcing and Gamification in the Cloud (CGCloud) %C Dresden, Germany %D 2013 %T Gamification Framework for Personalized Surveys on Relationships in Online Social Networks %X The estimation of psychological properties of relationships (e.g., popularity, influence, or trust) only from objective data in online social networks (OSNs) is a rather vague approach. A subjective assessment produces more accurate results, but it requires very complex and cumbersome surveys. The key contribution of this paper is a framework for personalized surveys on relationships in OSNs which follows a gamification approach. A game was developed and integrated into Facebook as an app, which makes it possible to obtain subjective ratings of users' relationships and objective data about the users, their interactions, and their social network. The combination of both subjective and objective data facilitates a deeper understanding of the psychological properties of relationships in OSNs, and lays the foundations for future research of subjective aspects within OSNs.
• YOUQMON: A System for On-line Monitoring of YouTube QoE in Operational 3G Networks. Casas, Pedro; Seufert, Michael; Schatz, Raimund. In 31st International Symposium on Computer Performance, Modeling, Measurements and Evaluation (IFIP Performance). Vienna, Austria, 2013.
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  YouTube is changing the way operators manage network performance monitoring. In this paper we present YOUQMON, a novel on-line monitoring system for assessing the Quality of Experience (QoE) undergone by HSPA/3G users watching YouTube videos, using network-layer measurements only. YOUQMON combines passive traffic analysis techniques to detect stalling events in YouTube video streams, with a QoE model to map stallings into a Mean Opinion Score reflecting the end-user experience. We evaluate the stalling detection performance of YOUQMON with hundreds of YouTube video streams, and present results showing the feasibility of performing real-time YouTube QoE monitoring in an operational mobile broadband network.

  @inproceedings{info3-inproceedings-2013-472, abstract = {YouTube is changing the way operators manage network performance monitoring. In this paper we present YOUQMON, a novel on-line monitoring system for assessing the Quality of Experience (QoE) undergone by HSPA/3G users watching YouTube videos, using network-layer measurements only. YOUQMON combines passive traffic analysis techniques to detect stalling events in YouTube video streams, with a QoE model to map stallings into a Mean Opinion Score reflecting the end-user experience. We evaluate the stalling detection performance of YOUQMON with hundreds of YouTube video streams, and present results showing the feasibility of performing real-time YouTube QoE monitoring in an operational mobile broadband network.}, address = {Vienna, Austria}, author = {Casas, Pedro and Seufert, Michael and Schatz, Raimund}, booktitle = {31st International Symposium on Computer Performance, Modeling, Measurements and Evaluation (IFIP Performance)}, keywords = {demobenefit}, month = {09}, title = {YOUQMON: A System for On-line Monitoring of YouTube QoE in Operational 3G Networks}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-472 %A Casas, Pedro %A Seufert, Michael %A Schatz, Raimund %B 31st International Symposium on Computer Performance, Modeling, Measurements and Evaluation (IFIP Performance) %C Vienna, Austria %D 2013 %T YOUQMON: A System for On-line Monitoring of YouTube QoE in Operational 3G Networks %X YouTube is changing the way operators manage network performance monitoring. In this paper we present YOUQMON, a novel on-line monitoring system for assessing the Quality of Experience (QoE) undergone by HSPA/3G users watching YouTube videos, using network-layer measurements only. YOUQMON combines passive traffic analysis techniques to detect stalling events in YouTube video streams, with a QoE model to map stallings into a Mean Opinion Score reflecting the end-user experience. We evaluate the stalling detection performance of YOUQMON with hundreds of YouTube video streams, and present results showing the feasibility of performing real-time YouTube QoE monitoring in an operational mobile broadband network.
• Dynamic HTTP Download Scheduling with Respect to Energy Consumption. Blenk, Andreas; Wamser, Florian; Zinner, Thomas; Kellerer, Wolfgang; Tran-Gia, Phuoc. In 24th Tyrrhenian International Workshop on Digital Communications (TIWDC). Genoa, Italy, 2013.
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  Mobile devices, in particular smartphones, are battery powered. As their small size limits their energy capacity, an intelligent and energy-saving use of resources is crucial for the mobile user experience. Especially energy saving while sending and receiving data becomes important due to the always-on nature of smartphones. One solution for a sophisticated resource usage in wireless access networks is to tailor resource management to applications. The advantage of such mechanisms is to be able to address both the perceived quality of the users and the energy consumption of mobile devices at the same time. We propose several traffic scheduling algorithms for HTTP file download in wireless networks based on this application-aware paradigm. The core idea is to use download scheduling that avoids parallel transmissions and, in contrast, favors sequential transmission. We have implemented and measured the algorithms in a wireless mesh network. The evaluation results quantify the gain of an application-aware resource management with respect to quality of experience and energy consumption.

  @inproceedings{info3-inproceedings-2013-479, abstract = {Mobile devices, in particular smartphones, are battery powered. As their small size limits their energy capacity, an intelligent and energy-saving use of resources is crucial for the mobile user experience. Especially energy saving while sending and receiving data becomes important due to the always-on nature of smartphones. One solution for a sophisticated resource usage in wireless access networks is to tailor resource management to applications. The advantage of such mechanisms is to be able to address both the perceived quality of the users and the energy consumption of mobile devices at the same time. We propose several traffic scheduling algorithms for HTTP file download in wireless networks based on this application-aware paradigm. The core idea is to use download scheduling that avoids parallel transmissions and, in contrast, favors sequential transmission. We have implemented and measured the algorithms in a wireless mesh network. The evaluation results quantify the gain of an application-aware resource management with respect to quality of experience and energy consumption.}, address = {Genoa, Italy}, author = {Blenk, Andreas and Wamser, Florian and Zinner, Thomas and Kellerer, Wolfgang and Tran-Gia, Phuoc}, booktitle = {24th Tyrrhenian International Workshop on Digital Communications (TIWDC)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Dynamic HTTP Download Scheduling with Respect to Energy Consumption}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-479 %A Blenk, Andreas %A Wamser, Florian %A Zinner, Thomas %A Kellerer, Wolfgang %A Tran-Gia, Phuoc %B 24th Tyrrhenian International Workshop on Digital Communications (TIWDC) %C Genoa, Italy %D 2013 %T Dynamic HTTP Download Scheduling with Respect to Energy Consumption %X Mobile devices, in particular smartphones, are battery powered. As their small size limits their energy capacity, an intelligent and energy-saving use of resources is crucial for the mobile user experience. Especially energy saving while sending and receiving data becomes important due to the always-on nature of smartphones. One solution for a sophisticated resource usage in wireless access networks is to tailor resource management to applications. The advantage of such mechanisms is to be able to address both the perceived quality of the users and the energy consumption of mobile devices at the same time. We propose several traffic scheduling algorithms for HTTP file download in wireless networks based on this application-aware paradigm. The core idea is to use download scheduling that avoids parallel transmissions and, in contrast, favors sequential transmission. We have implemented and measured the algorithms in a wireless mesh network. The evaluation results quantify the gain of an application-aware resource management with respect to quality of experience and energy consumption.
• Pareto-Optimal Resilient Controller Placement in SDN-based Core Networks. Hock, David; Hartmann, Matthias; Gebert, Steffen; Jarschel, Michael; Zinner, Thomas; Tran-Gia, Phuoc. In 25th International Teletraffic Congress (ITC). Shanghai, China, 2013.
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  With the introduction of Software Defined Networking (SDN), the concept of an external and optionally centralized network control plane, i.e. controller, is drawing the attention of researchers and industry. A particularly important task in the SDN context is the placement of such external resources in the network. In this paper, we discuss important aspects of the controller placement problem with a focus on SDN-based core networks, including different types of resilience and failure tolerance. When several performance and resilience metrics are considered, there is usually no single best controller placement solution, but a trade-off between these metrics. We introduce our framework for resilient Pareto-based Optimal COntroller-placement (POCO) that provides the operator of a network with all Pareto-optimal placements. The ideas and mechanisms are illustrated using the Internet2 OS3E topology and further evaluated on more than 140 topologies of the Topology Zoo. In particular, our findings reveal that for most of the topologies more than 20% of all nodes need to be controllers to assure a continuous connection of all nodes to one of the controllers in any arbitrary double link or node failure scenario.

  @inproceedings{info3-inproceedings-2013-466, abstract = {With the introduction of Software Defined Networking (SDN), the concept of an external and optionally centralized network control plane, i.e. controller, is drawing the attention of researchers and industry. A particularly important task in the SDN context is the placement of such external resources in the network. In this paper, we discuss important aspects of the controller placement problem with a focus on SDN-based core networks, including different types of resilience and failure tolerance. When several performance and resilience metrics are considered, there is usually no single best controller placement solution, but a trade-off between these metrics. We introduce our framework for resilient Pareto-based Optimal COntroller-placement (POCO) that provides the operator of a network with all Pareto-optimal placements. The ideas and mechanisms are illustrated using the Internet2 OS3E topology and further evaluated on more than 140 topologies of the Topology Zoo. In particular, our findings reveal that for most of the topologies more than 20% of all nodes need to be controllers to assure a continuous connection of all nodes to one of the controllers in any arbitrary double link or node failure scenario.}, address = {Shanghai, China}, author = {Hock, David and Hartmann, Matthias and Gebert, Steffen and Jarschel, Michael and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {25th International Teletraffic Congress (ITC)}, keywords = {poco}, month = {09}, title = {Pareto-Optimal Resilient Controller Placement in SDN-based Core Networks}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-466 %A Hock, David %A Hartmann, Matthias %A Gebert, Steffen %A Jarschel, Michael %A Zinner, Thomas %A Tran-Gia, Phuoc %B 25th International Teletraffic Congress (ITC) %C Shanghai, China %D 2013 %T Pareto-Optimal Resilient Controller Placement in SDN-based Core Networks %X With the introduction of Software Defined Networking (SDN), the concept of an external and optionally centralized network control plane, i.e. controller, is drawing the attention of researchers and industry. A particularly important task in the SDN context is the placement of such external resources in the network. In this paper, we discuss important aspects of the controller placement problem with a focus on SDN-based core networks, including different types of resilience and failure tolerance. When several performance and resilience metrics are considered, there is usually no single best controller placement solution, but a trade-off between these metrics. We introduce our framework for resilient Pareto-based Optimal COntroller-placement (POCO) that provides the operator of a network with all Pareto-optimal placements. The ideas and mechanisms are illustrated using the Internet2 OS3E topology and further evaluated on more than 140 topologies of the Topology Zoo. In particular, our findings reveal that for most of the topologies more than 20% of all nodes need to be controllers to assure a continuous connection of all nodes to one of the controllers in any arbitrary double link or node failure scenario.
• Need for Speed? On Quality of Experience for File Storage Services. Amrehn, Philipp; Vandenbroucke, Karel; Hoßfeld, Tobias; de Moor, Katrien; Hirth, Matthias; Schatz, Raimund; Casas, Pedro. In 4th International Workshop on Perceptual Quality of Systems (PQS 2013). Vienna, Austria, 2013.
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  Cloud computing has received a lot of attention within several research domains. However, there are only a few studies that focus on Quality of Experience (QoE) from a user perspective in the context of personal cloud storage services. In order to gain insights in existing use practices and to detect possible QoE influencing factors and relevant features, we conducted an online survey amongst users of personal cloud storage services and applications in general (N=349) and one specifically targeted at Dropbox users (N=49). Both studies point to accessibility, data sharing and data back-up as key features of personal cloud storage services. In addition, performance, i.e. upload and download speed, goes hand in hand with synchro-nization speed and should be taken into account when measur-ing QoE. However, cost, privacy and security related issues are as important factors as well.

  @inproceedings{info3-inproceedings-2013-469, abstract = {Cloud computing has received a lot of attention within several research domains. However, there are only a few studies that focus on Quality of Experience (QoE) from a user perspective in the context of personal cloud storage services. In order to gain insights in existing use practices and to detect possible QoE influencing factors and relevant features, we conducted an online survey amongst users of personal cloud storage services and applications in general (N=349) and one specifically targeted at Dropbox users (N=49). Both studies point to accessibility, data sharing and data back-up as key features of personal cloud storage services. In addition, performance, i.e. upload and download speed, goes hand in hand with synchro-nization speed and should be taken into account when measur-ing QoE. However, cost, privacy and security related issues are as important factors as well.}, address = {Vienna, Austria}, author = {Amrehn, Philipp and Vandenbroucke, Karel and Hoßfeld, Tobias and de Moor, Katrien and Hirth, Matthias and Schatz, Raimund and Casas, Pedro}, booktitle = {4th International Workshop on Perceptual Quality of Systems (PQS 2013)}, keywords = {smartenit}, month = {09}, title = {Need for Speed? On Quality of Experience for File Storage Services}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-469 %A Amrehn, Philipp %A Vandenbroucke, Karel %A Hoßfeld, Tobias %A de Moor, Katrien %A Hirth, Matthias %A Schatz, Raimund %A Casas, Pedro %B 4th International Workshop on Perceptual Quality of Systems (PQS 2013) %C Vienna, Austria %D 2013 %T Need for Speed? On Quality of Experience for File Storage Services %X Cloud computing has received a lot of attention within several research domains. However, there are only a few studies that focus on Quality of Experience (QoE) from a user perspective in the context of personal cloud storage services. In order to gain insights in existing use practices and to detect possible QoE influencing factors and relevant features, we conducted an online survey amongst users of personal cloud storage services and applications in general (N=349) and one specifically targeted at Dropbox users (N=49). Both studies point to accessibility, data sharing and data back-up as key features of personal cloud storage services. In addition, performance, i.e. upload and download speed, goes hand in hand with synchro-nization speed and should be taken into account when measur-ing QoE. However, cost, privacy and security related issues are as important factors as well.
• Socially-Aware Traffic Management. Seufert, Michael; Darzanos, George; Burger, Valentin; Papafili, Ioanna; Hoßfeld, Tobias. In Workshop Sozioinformatik. Koblenz, Germany, 2013.
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  Socially-aware traffic management exploits social signals to optimize traffic management in the Internet in terms of traffic load, energy consumption, or end-user satisfaction. Several use cases can benefit from socially-aware traffic management and the performance of overlay applications can be enhanced. In the talk we show interdisciplinary efforts between communication networks and social network analysis. Specifically, we give an overview on existing use cases and solutions, but also raise discussions at the workshop on additional benefits from the integration of social information into traffic management.

  @inproceedings{info3-inproceedings-2013-471, abstract = {Socially-aware traffic management exploits social signals to optimize traffic management in the Internet in terms of traffic load, energy consumption, or end-user satisfaction. Several use cases can benefit from socially-aware traffic management and the performance of overlay applications can be enhanced. In the talk we show interdisciplinary efforts between communication networks and social network analysis. Specifically, we give an overview on existing use cases and solutions, but also raise discussions at the workshop on additional benefits from the integration of social information into traffic management.}, address = {Koblenz, Germany}, author = {Seufert, Michael and Darzanos, George and Burger, Valentin and Papafili, Ioanna and Hoßfeld, Tobias}, booktitle = {Workshop Sozioinformatik}, keywords = {smartenit}, month = {09}, title = {Socially-Aware Traffic Management}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-471 %A Seufert, Michael %A Darzanos, George %A Burger, Valentin %A Papafili, Ioanna %A Hoßfeld, Tobias %B Workshop Sozioinformatik %C Koblenz, Germany %D 2013 %T Socially-Aware Traffic Management %X Socially-aware traffic management exploits social signals to optimize traffic management in the Internet in terms of traffic load, energy consumption, or end-user satisfaction. Several use cases can benefit from socially-aware traffic management and the performance of overlay applications can be enhanced. In the talk we show interdisciplinary efforts between communication networks and social network analysis. Specifically, we give an overview on existing use cases and solutions, but also raise discussions at the workshop on additional benefits from the integration of social information into traffic management.
• Asking Costs Little? The Impact of Tasks in Video QoE Studies on User Behavior and User Ratings. Sackl, Andreas; Seufert, Michael; Hoßfeld, Tobias. In 4th International Workshop on Perceptual Quality of Systems (PQS). Vienna, Austria, 2013.
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  Three crowdsourcing video QoE studies have been conducted to investigate the influence of tasks on user behavior and quality perception. Different dimensions of tasks have been applied to impaired video clips and their impact on task success, focus time, and QoE was measured. Our findings suggest that task presence or absence has no influence on the user. However, continuous tasks can improve the focus times of users, and hard tasks are suitable to filter unreliable participants.

  @inproceedings{info3-inproceedings-2013-467, abstract = {Three crowdsourcing video QoE studies have been conducted to investigate the influence of tasks on user behavior and quality perception. Different dimensions of tasks have been applied to impaired video clips and their impact on task success, focus time, and QoE was measured. Our findings suggest that task presence or absence has no influence on the user. However, continuous tasks can improve the focus times of users, and hard tasks are suitable to filter unreliable participants.}, address = {Vienna, Austria}, author = {Sackl, Andreas and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {4th International Workshop on Perceptual Quality of Systems (PQS)}, keywords = {oekonet}, month = {09}, title = {Asking Costs Little? The Impact of Tasks in Video QoE Studies on User Behavior and User Ratings}, year = 2013 }

  %0 Conference Paper %1 info3-inproceedings-2013-467 %A Sackl, Andreas %A Seufert, Michael %A Hoßfeld, Tobias %B 4th International Workshop on Perceptual Quality of Systems (PQS) %C Vienna, Austria %D 2013 %T Asking Costs Little? The Impact of Tasks in Video QoE Studies on User Behavior and User Ratings %X Three crowdsourcing video QoE studies have been conducted to investigate the influence of tasks on user behavior and quality perception. Different dimensions of tasks have been applied to impaired video clips and their impact on task success, focus time, and QoE was measured. Our findings suggest that task presence or absence has no influence on the user. However, continuous tasks can improve the focus times of users, and hard tasks are suitable to filter unreliable participants.

• Quality Adaptation in P2P Video Streaming based on Objective QoE Assessment. Rückert, Julius; Abboud, Osama; Zinner, Thomas; Hausheer, David; Steinmetz, Ralf. In FIP/TC6 NETWORKING 2012 (NETWORKING 2012). Prague, 2012.
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  The transmission of video data is a major part of traffc on today's Internet. Since the Internet is a highly dynamic environment, quality adaptation is essential in matching user device resources with the streamed video quality. This can be achieved by applying mechanisms that follow the Scalable Video Coding (SVC) standard, which enables scalability of the video quality in multiple dimensions. In SVCbased streaming, adaptation decisions have long been driven by Quality of Service (QoS) metrics, such as throughput. However, these metrics do not very well match the way human users perceive video quality. Therefore, in this paper, the classical SVC-based video streaming approach is expanded to consider Quality of Experience (QoE) for adaptation decisions. The video quality is assessed using existing objective techniques with a high correlation to the human perception of video quality. The approach is evaluated in context of a P2P-based Video-on-Demand (VoD) system and shows that by making peers favor always layers with a high estimated QoE but not necessarily high bandwidth requirements, the performance of the entire system can be enhanced in terms of playback delay and SVC video quality by up to 20%. At the same time, content providers are able to reduce up to 60% of their server costs, compared to the classical QoS-based approach.

  @inproceedings{info3-inproceedings-2012-439, abstract = {The transmission of video data is a major part of traffc on today's Internet. Since the Internet is a highly dynamic environment, quality adaptation is essential in matching user device resources with the streamed video quality. This can be achieved by applying mechanisms that follow the Scalable Video Coding (SVC) standard, which enables scalability of the video quality in multiple dimensions. In SVCbased streaming, adaptation decisions have long been driven by Quality of Service (QoS) metrics, such as throughput. However, these metrics do not very well match the way human users perceive video quality. Therefore, in this paper, the classical SVC-based video streaming approach is expanded to consider Quality of Experience (QoE) for adaptation decisions. The video quality is assessed using existing objective techniques with a high correlation to the human perception of video quality. The approach is evaluated in context of a P2P-based Video-on-Demand (VoD) system and shows that by making peers favor always layers with a high estimated QoE but not necessarily high bandwidth requirements, the performance of the entire system can be enhanced in terms of playback delay and SVC video quality by up to 20%. At the same time, content providers are able to reduce up to 60% of their server costs, compared to the classical QoS-based approach.}, address = {Prague}, author = {Rückert, Julius and Abboud, Osama and Zinner, Thomas and Hausheer, David and Steinmetz, Ralf}, booktitle = {FIP/TC6 NETWORKING 2012 (NETWORKING 2012)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Quality Adaptation in P2P Video Streaming based on Objective QoE Assessment}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-439 %A Rückert, Julius %A Abboud, Osama %A Zinner, Thomas %A Hausheer, David %A Steinmetz, Ralf %B FIP/TC6 NETWORKING 2012 (NETWORKING 2012) %C Prague %D 2012 %T Quality Adaptation in P2P Video Streaming based on Objective QoE Assessment %X The transmission of video data is a major part of traffc on today's Internet. Since the Internet is a highly dynamic environment, quality adaptation is essential in matching user device resources with the streamed video quality. This can be achieved by applying mechanisms that follow the Scalable Video Coding (SVC) standard, which enables scalability of the video quality in multiple dimensions. In SVCbased streaming, adaptation decisions have long been driven by Quality of Service (QoS) metrics, such as throughput. However, these metrics do not very well match the way human users perceive video quality. Therefore, in this paper, the classical SVC-based video streaming approach is expanded to consider Quality of Experience (QoE) for adaptation decisions. The video quality is assessed using existing objective techniques with a high correlation to the human perception of video quality. The approach is evaluated in context of a P2P-based Video-on-Demand (VoD) system and shows that by making peers favor always layers with a high estimated QoE but not necessarily high bandwidth requirements, the performance of the entire system can be enhanced in terms of playback delay and SVC video quality by up to 20%. At the same time, content providers are able to reduce up to 60% of their server costs, compared to the classical QoS-based approach.
• An HTTP Web Traffic Model Based on the Top One Million Visited Web Pages. Pries, Rastin; Magyari, Zsolt; Tran-Gia, Phuoc. In 8th Euro-NF Conference on Next Generation Internet. Karlskrona, Sweden, 2012.
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  @inproceedings{info3-inproceedings-2012-445, address = {Karlskrona, Sweden}, author = {Pries, Rastin and Magyari, Zsolt and Tran-Gia, Phuoc}, booktitle = {8th Euro-NF Conference on Next Generation Internet}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {An HTTP Web Traffic Model Based on the Top One Million Visited Web Pages}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-445 %A Pries, Rastin %A Magyari, Zsolt %A Tran-Gia, Phuoc %B 8th Euro-NF Conference on Next Generation Internet %C Karlskrona, Sweden %D 2012 %T An HTTP Web Traffic Model Based on the Top One Million Visited Web Pages
• Experimental Demonstration of Network Virtualization and Resource Flexibility in the COMCON Project. Duelli, Michael; Meier, Sebastian; Wagner, David; Zinner, Thomas; Schmid, Matthias; Hoffmann, Marco; Kiess, Wolfgang. In 8th International ICST Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities. Thessaloniki, 2012.
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  In the recent past, Network Virtualization (NV) received much attention. In the beginning, the Future Internet research community was interested in deploying innovative protocols in isolated networks. Then, business models have been developed that separate functions today being united in the Internet Service Provider (ISP) and by that defining a vertically and horizontally divided market. Nevertheless, Virtual Net- works (VNs) are still not available on the market. The consortium of the COntrol and Management of COexisting Networks (COMCON) project examines the potential interactions in such divided market and evaluates the applicability of existing technologies for automated virtualizationenabled network management. To promote the manifold research, a selected scenario was demonstrated at the Euroview 2011. The network virtualization in this scenario is based on Generalized Multi-Protocol La- bel Switching (GMPLS) and allows exible resource provisioning, i.e. the topology and its elements may be changed during life time of the VN. As innovative service we selected a Video on Demand (VoD) service using a Scalable Video Codec (SVC) that allows to route the video on layer granularity. A multi-level multi-tennant monitoring system is used to provide status information on physical as well as on virtual network level. The scenario shows how exible VN provisioning and innovative services may interact across the different players and by that solving challenging situations. All necessary components have been implemented and the selected scenario has been executed on a real network based on Linux PCs. In this paper, we describe the components, the scenario and the insights gained in more detail.

  @inproceedings{info3-inproceedings-2012-443, abstract = {In the recent past, Network Virtualization (NV) received much attention. In the beginning, the Future Internet research community was interested in deploying innovative protocols in isolated networks. Then, business models have been developed that separate functions today being united in the Internet Service Provider (ISP) and by that defining a vertically and horizontally divided market. Nevertheless, Virtual Net- works (VNs) are still not available on the market. The consortium of the COntrol and Management of COexisting Networks (COMCON) project examines the potential interactions in such divided market and evaluates the applicability of existing technologies for automated virtualizationenabled network management. To promote the manifold research, a selected scenario was demonstrated at the Euroview 2011. The network virtualization in this scenario is based on Generalized Multi-Protocol La- bel Switching (GMPLS) and allows exible resource provisioning, i.e. the topology and its elements may be changed during life time of the VN. As innovative service we selected a Video on Demand (VoD) service using a Scalable Video Codec (SVC) that allows to route the video on layer granularity. A multi-level multi-tennant monitoring system is used to provide status information on physical as well as on virtual network level. The scenario shows how exible VN provisioning and innovative services may interact across the different players and by that solving challenging situations. All necessary components have been implemented and the selected scenario has been executed on a real network based on Linux PCs. In this paper, we describe the components, the scenario and the insights gained in more detail.}, address = {Thessaloniki}, author = {Duelli, Michael and Meier, Sebastian and Wagner, David and Zinner, Thomas and Schmid, Matthias and Hoffmann, Marco and Kiess, Wolfgang}, booktitle = {8th International ICST Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Experimental Demonstration of Network Virtualization and Resource Flexibility in the COMCON Project}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-443 %A Duelli, Michael %A Meier, Sebastian %A Wagner, David %A Zinner, Thomas %A Schmid, Matthias %A Hoffmann, Marco %A Kiess, Wolfgang %B 8th International ICST Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities %C Thessaloniki %D 2012 %T Experimental Demonstration of Network Virtualization and Resource Flexibility in the COMCON Project %X In the recent past, Network Virtualization (NV) received much attention. In the beginning, the Future Internet research community was interested in deploying innovative protocols in isolated networks. Then, business models have been developed that separate functions today being united in the Internet Service Provider (ISP) and by that defining a vertically and horizontally divided market. Nevertheless, Virtual Net- works (VNs) are still not available on the market. The consortium of the COntrol and Management of COexisting Networks (COMCON) project examines the potential interactions in such divided market and evaluates the applicability of existing technologies for automated virtualizationenabled network management. To promote the manifold research, a selected scenario was demonstrated at the Euroview 2011. The network virtualization in this scenario is based on Generalized Multi-Protocol La- bel Switching (GMPLS) and allows exible resource provisioning, i.e. the topology and its elements may be changed during life time of the VN. As innovative service we selected a Video on Demand (VoD) service using a Scalable Video Codec (SVC) that allows to route the video on layer granularity. A multi-level multi-tennant monitoring system is used to provide status information on physical as well as on virtual network level. The scenario shows how exible VN provisioning and innovative services may interact across the different players and by that solving challenging situations. All necessary components have been implemented and the selected scenario has been executed on a real network based on Linux PCs. In this paper, we describe the components, the scenario and the insights gained in more detail.
• On the Usability of OpenFlow in Data Center Environments. Pries, Rastin; Jarschel, Michael; Goll, Sebastian. In Workshop on Clouds, Networks and Data Centers collocated with the IEEE International Conference on Communications (ICC 2012). Ottawa, Canada, 2012.
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  Since its introduction OpenFlow has been used as an enabler for network experiments in a variety of fields. Although OpenFlow was initially only used in the research domain, the concept is now finding its way into data centers due to the relatively cheap hardware and high flexibility. In this paper, we take a look at the scalability and usability of OpenFlow in data centers. Based on data center traffic models and OpenFlow measurements, we evaluate whether OpenFlow is able to cope with the short flow inter-arrival times in data centers by means of simulation.

  @inproceedings{info3-inproceedings-2012-438, abstract = {Since its introduction OpenFlow has been used as an enabler for network experiments in a variety of fields. Although OpenFlow was initially only used in the research domain, the concept is now finding its way into data centers due to the relatively cheap hardware and high flexibility. In this paper, we take a look at the scalability and usability of OpenFlow in data centers. Based on data center traffic models and OpenFlow measurements, we evaluate whether OpenFlow is able to cope with the short flow inter-arrival times in data centers by means of simulation.}, address = {Ottawa, Canada}, author = {Pries, Rastin and Jarschel, Michael and Goll, Sebastian}, booktitle = {Workshop on Clouds, Networks and Data Centers collocated with the IEEE International Conference on Communications (ICC 2012)}, keywords = {openflow}, month = {06}, title = {On the Usability of OpenFlow in Data Center Environments}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-438 %A Pries, Rastin %A Jarschel, Michael %A Goll, Sebastian %B Workshop on Clouds, Networks and Data Centers collocated with the IEEE International Conference on Communications (ICC 2012) %C Ottawa, Canada %D 2012 %T On the Usability of OpenFlow in Data Center Environments %X Since its introduction OpenFlow has been used as an enabler for network experiments in a variety of fields. Although OpenFlow was initially only used in the research domain, the concept is now finding its way into data centers due to the relatively cheap hardware and high flexibility. In this paper, we take a look at the scalability and usability of OpenFlow in data centers. Based on data center traffic models and OpenFlow measurements, we evaluate whether OpenFlow is able to cope with the short flow inter-arrival times in data centers by means of simulation.
• A performance evaluation framework for video streaming. Metzger, Florian; Rafetseder, Albert; Tutschku, Kurt. In 19th International Packet Video Workshop (PV). 2012.
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  In this paper, we present a generic framework for performance evaluation of video streams. We embrace the perspective of a streaming application, and model the playback buffer level at given network and playback conditions. That way, our model enables flexible, adaptable evaluation of a wide variety of streaming methods and protocols. We test our model on HTML5 and Flash video as served by the YouTube web site. We find universal achievable limits in any streaming process, and explore quality trade-offs every application has to decide on.

  @inproceedings{info3-inproceedings-2012-27, abstract = {In this paper, we present a generic framework for performance evaluation of video streams. We embrace the perspective of a streaming application, and model the playback buffer level at given network and playback conditions. That way, our model enables flexible, adaptable evaluation of a wide variety of streaming methods and protocols. We test our model on HTML5 and Flash video as served by the YouTube web site. We find universal achievable limits in any streaming process, and explore quality trade-offs every application has to decide on.}, author = {Metzger, Florian and Rafetseder, Albert and Tutschku, Kurt}, booktitle = {19th International Packet Video Workshop (PV)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {A performance evaluation framework for video streaming}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-27 %A Metzger, Florian %A Rafetseder, Albert %A Tutschku, Kurt %B 19th International Packet Video Workshop (PV) %D 2012 %T A performance evaluation framework for video streaming %X In this paper, we present a generic framework for performance evaluation of video streams. We embrace the perspective of a streaming application, and model the playback buffer level at given network and playback conditions. That way, our model enables flexible, adaptable evaluation of a wide variety of streaming methods and protocols. We test our model on HTML5 and Flash video as served by the YouTube web site. We find universal achievable limits in any streaming process, and explore quality trade-offs every application has to decide on.
• Integration of LISP and LISP-MN into INET. Klein, Dominik; Höfling, Michael; Hartmann, Matthias; Menth, Michael. In 5th International Workshop on OMNeT++, pp. 299–306. Desenzano, Italy, 2012.
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  The Locator/Identifier Separation Protocol (LISP) is a new naming and addressing architecture which is currently standardized in the IETF and which is deemed to improve the scalability and flexibility of the current routing architecture. LISP mobile node (LISP-MN) is an extension to the basic LISP architecture and enables mobile nodes to roam into LISP and non-LISP domains. The basic LISP architecture is currently deployed in a beta-network which can be used to test the protocol behavior on a smaller scale. However, a realistic simulation model for the LISP architecture and its various extensions is still missing. Such a simulation model could be used by researchers to quickly test new extensions on a larger scale for different load and network scenarios. In this paper, we describe the implementation of our model of the LISP architecture and its various extensions in the INET framework for OMNeT++. We present performance results to show the correctness of our model. As a first application, we used the simulation model to assess proposed improvements to LISP-MN and to verify our proposed NAT traversal mechanism for LISP-MN.

  @inproceedings{info3-inproceedings-2012-435, abstract = {The Locator/Identifier Separation Protocol (LISP) is a new naming and addressing architecture which is currently standardized in the IETF and which is deemed to improve the scalability and flexibility of the current routing architecture. LISP mobile node (LISP-MN) is an extension to the basic LISP architecture and enables mobile nodes to roam into LISP and non-LISP domains. The basic LISP architecture is currently deployed in a beta-network which can be used to test the protocol behavior on a smaller scale. However, a realistic simulation model for the LISP architecture and its various extensions is still missing. Such a simulation model could be used by researchers to quickly test new extensions on a larger scale for different load and network scenarios. In this paper, we describe the implementation of our model of the LISP architecture and its various extensions in the INET framework for OMNeT++. We present performance results to show the correctness of our model. As a first application, we used the simulation model to assess proposed improvements to LISP-MN and to verify our proposed NAT traversal mechanism for LISP-MN.}, address = {Desenzano, Italy}, author = {Klein, Dominik and Höfling, Michael and Hartmann, Matthias and Menth, Michael}, booktitle = {5th International Workshop on OMNeT++}, keywords = {sys:hidden:inproceedings}, month = {03}, pages = {299-306}, title = {Integration of LISP and LISP-MN into INET}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-435 %A Klein, Dominik %A Höfling, Michael %A Hartmann, Matthias %A Menth, Michael %B 5th International Workshop on OMNeT++ %C Desenzano, Italy %D 2012 %P 299-306 %T Integration of LISP and LISP-MN into INET %X The Locator/Identifier Separation Protocol (LISP) is a new naming and addressing architecture which is currently standardized in the IETF and which is deemed to improve the scalability and flexibility of the current routing architecture. LISP mobile node (LISP-MN) is an extension to the basic LISP architecture and enables mobile nodes to roam into LISP and non-LISP domains. The basic LISP architecture is currently deployed in a beta-network which can be used to test the protocol behavior on a smaller scale. However, a realistic simulation model for the LISP architecture and its various extensions is still missing. Such a simulation model could be used by researchers to quickly test new extensions on a larger scale for different load and network scenarios. In this paper, we describe the implementation of our model of the LISP architecture and its various extensions in the INET framework for OMNeT++. We present performance results to show the correctness of our model. As a first application, we used the simulation model to assess proposed improvements to LISP-MN and to verify our proposed NAT traversal mechanism for LISP-MN.
• Impact of Screening Technique on Crowdsourcing QoE Assessments. Gardlo, Bruno; Ries, Michal; Hoßfeld, Tobias. In 22nd International Conference Radioelektronika 2012, Special Session on Quality in multimedia systems. Brno, Czech Republic, 2012.
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  Evaluation of quality as perceived by the user in his natural environment is a difficult and strenuous task. Simulation of real world conditions in the laboratory is often inefficient and expensive. Recently, crowdsourcing as novel methodology for testing Quality of Experience (QoE) at the end user side has been proposed. In this paper we discuss (a) the challenges of performing subjective assessments in the crowdsourcing domain and (b) highlight the importance of proper filtering of unreliable users from the overall results. In particular, we introduce various ways for detecting unreliable users and compare results from two similar QoE studies applying different screening techniques.

  @inproceedings{info3-inproceedings-2012-441, abstract = {Evaluation of quality as perceived by the user in his natural environment is a difficult and strenuous task. Simulation of real world conditions in the laboratory is often inefficient and expensive. Recently, crowdsourcing as novel methodology for testing Quality of Experience (QoE) at the end user side has been proposed. In this paper we discuss (a) the challenges of performing subjective assessments in the crowdsourcing domain and (b) highlight the importance of proper filtering of unreliable users from the overall results. In particular, we introduce various ways for detecting unreliable users and compare results from two similar QoE studies applying different screening techniques.}, address = {Brno, Czech Republic}, author = {Gardlo, Bruno and Ries, Michal and Hoßfeld, Tobias}, booktitle = {22nd International Conference Radioelektronika 2012, Special Session on Quality in multimedia systems}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Impact of Screening Technique on Crowdsourcing QoE Assessments}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-441 %A Gardlo, Bruno %A Ries, Michal %A Hoßfeld, Tobias %B 22nd International Conference Radioelektronika 2012, Special Session on Quality in multimedia systems %C Brno, Czech Republic %D 2012 %T Impact of Screening Technique on Crowdsourcing QoE Assessments %X Evaluation of quality as perceived by the user in his natural environment is a difficult and strenuous task. Simulation of real world conditions in the laboratory is often inefficient and expensive. Recently, crowdsourcing as novel methodology for testing Quality of Experience (QoE) at the end user side has been proposed. In this paper we discuss (a) the challenges of performing subjective assessments in the crowdsourcing domain and (b) highlight the importance of proper filtering of unreliable users from the overall results. In particular, we introduce various ways for detecting unreliable users and compare results from two similar QoE studies applying different screening techniques.
• Cache Capacity Allocation for BitTorrent-like Systems to Minimize Inter-ISP Traffic. Pacifici, Valentino; Lehrieder, Frank; Dán, György. In IEEE Infocom. Orlando, USA, 2012.
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  Many Internet service providers (ISPs) have deployed peer-to-peer (P2P) caches in their networks in order to decrease costly inter-ISP traffic. A P2P cache stores parts of the most popular contents locally, and if possible serves the requests of local peers to decrease the transit traffic. Traditionally, P2P cache resource management focuses on managing the storage resource of the cache such as to maximize the transit traffic savings. In this paper we show that when there are many overlays competing for the upload bandwidth of a P2P cache then in order to maximize the transit traffic savings the cache’s upload bandwidth should be actively allocated among the overlays. We formulate the problem of P2P cache capacity allocation as a Markov decision process, and describe two approximations to the optimal cache capacity allocation policy. Based on the insights obtained from the approximate policies we propose a cache capacity allocation policy for BitTorrent-like P2P networks. We use extensive simulations to evaluate the performance of the proposed policies, and show that cache capacity allocation can improve the transit traffic savings by up to 30 to 60 percent. We validate the results via BitTorrent experiments on Planet-lab.

  @inproceedings{info3-inproceedings-2012-431, abstract = {Many Internet service providers (ISPs) have deployed peer-to-peer (P2P) caches in their networks in order to decrease costly inter-ISP traffic. A P2P cache stores parts of the most popular contents locally, and if possible serves the requests of local peers to decrease the transit traffic. Traditionally, P2P cache resource management focuses on managing the storage resource of the cache such as to maximize the transit traffic savings. In this paper we show that when there are many overlays competing for the upload bandwidth of a P2P cache then in order to maximize the transit traffic savings the cache’s upload bandwidth should be actively allocated among the overlays. We formulate the problem of P2P cache capacity allocation as a Markov decision process, and describe two approximations to the optimal cache capacity allocation policy. Based on the insights obtained from the approximate policies we propose a cache capacity allocation policy for BitTorrent-like P2P networks. We use extensive simulations to evaluate the performance of the proposed policies, and show that cache capacity allocation can improve the transit traffic savings by up to 30 to 60 percent. We validate the results via BitTorrent experiments on Planet-lab.}, address = {Orlando, USA}, author = {Pacifici, Valentino and Lehrieder, Frank and Dán, György}, booktitle = {IEEE Infocom}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Cache Capacity Allocation for BitTorrent-like Systems to Minimize Inter-ISP Traffic}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-431 %A Pacifici, Valentino %A Lehrieder, Frank %A Dán, György %B IEEE Infocom %C Orlando, USA %D 2012 %T Cache Capacity Allocation for BitTorrent-like Systems to Minimize Inter-ISP Traffic %X Many Internet service providers (ISPs) have deployed peer-to-peer (P2P) caches in their networks in order to decrease costly inter-ISP traffic. A P2P cache stores parts of the most popular contents locally, and if possible serves the requests of local peers to decrease the transit traffic. Traditionally, P2P cache resource management focuses on managing the storage resource of the cache such as to maximize the transit traffic savings. In this paper we show that when there are many overlays competing for the upload bandwidth of a P2P cache then in order to maximize the transit traffic savings the cache’s upload bandwidth should be actively allocated among the overlays. We formulate the problem of P2P cache capacity allocation as a Markov decision process, and describe two approximations to the optimal cache capacity allocation policy. Based on the insights obtained from the approximate policies we propose a cache capacity allocation policy for BitTorrent-like P2P networks. We use extensive simulations to evaluate the performance of the proposed policies, and show that cache capacity allocation can improve the transit traffic savings by up to 30 to 60 percent. We validate the results via BitTorrent experiments on Planet-lab.
• Internet Access Traffic Measurement and Analysis. Gebert, Steffen; Pries, Rastin; Schlosser, Daniel; Heck, Klaus. In Traffic Monitoring and Analysis (TMA) workshop co-located with the 13th Passive and Active Measurement (PAM) conference. Vienna, Austria, 2012.
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  The fast changing application types and their behavior require consecutive measurements of access networks. In this paper, we present the results of a 14-day measurement in an access network connecting 600 users with the Internet. Our application classification reveals a trend back to HTTP traffic, underlines the immense usage of flash videos, and unveils a participant of a Botnet. In addition, flow and user statistics are presented, which resulting traffic models can be used for simulation and emulation of access networks.

  @inproceedings{info3-inproceedings-2012-432, abstract = {The fast changing application types and their behavior require consecutive measurements of access networks. In this paper, we present the results of a 14-day measurement in an access network connecting 600 users with the Internet. Our application classification reveals a trend back to HTTP traffic, underlines the immense usage of flash videos, and unveils a participant of a Botnet. In addition, flow and user statistics are presented, which resulting traffic models can be used for simulation and emulation of access networks.}, address = {Vienna, Austria}, author = {Gebert, Steffen and Pries, Rastin and Schlosser, Daniel and Heck, Klaus}, booktitle = {Traffic Monitoring and Analysis (TMA) workshop co-located with the 13th Passive and Active Measurement (PAM) conference}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Internet Access Traffic Measurement and Analysis}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-432 %A Gebert, Steffen %A Pries, Rastin %A Schlosser, Daniel %A Heck, Klaus %B Traffic Monitoring and Analysis (TMA) workshop co-located with the 13th Passive and Active Measurement (PAM) conference %C Vienna, Austria %D 2012 %T Internet Access Traffic Measurement and Analysis %X The fast changing application types and their behavior require consecutive measurements of access networks. In this paper, we present the results of a 14-day measurement in an access network connecting 600 users with the Internet. Our application classification reveals a trend back to HTTP traffic, underlines the immense usage of flash videos, and unveils a participant of a Botnet. In addition, flow and user statistics are presented, which resulting traffic models can be used for simulation and emulation of access networks.
• A Queuing Analysis of an Energy-Saving Mechanism in Data Centers. Schwartz, Christian; Pries, Rastin; Tran-Gia, Phuoc. In International Conference on Information Networking (ICOIN). Bali, Indonesia, 2012.
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  The high energy costs for running a data center led to a rethinking towards an energy-efficient operation of a data center. Designed for supporting the expected peak traffic load, the goal of the data center provider such as Amazon or Google is now to dynamically adapt the number of offered resources according to the current traffic load. In this paper, we present a queuing theoretical model to evaluate the trade-off between waiting time and power consumption if only a subset of servers is active all the time and the remaining servers are enabled on demand. We develop a queuing model with thresholds to turn-on reserve servers when needed. Furthermore, the resulting system behavior under varying parameters and requirements for Pareto optimality are studied.

  @inproceedings{info3-inproceedings-2012-430, abstract = {The high energy costs for running a data center led to a rethinking towards an energy-efficient operation of a data center. Designed for supporting the expected peak traffic load, the goal of the data center provider such as Amazon or Google is now to dynamically adapt the number of offered resources according to the current traffic load. In this paper, we present a queuing theoretical model to evaluate the trade-off between waiting time and power consumption if only a subset of servers is active all the time and the remaining servers are enabled on demand. We develop a queuing model with thresholds to turn-on reserve servers when needed. Furthermore, the resulting system behavior under varying parameters and requirements for Pareto optimality are studied.}, address = {Bali, Indonesia}, author = {Schwartz, Christian and Pries, Rastin and Tran-Gia, Phuoc}, booktitle = {International Conference on Information Networking (ICOIN)}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {A Queuing Analysis of an Energy-Saving Mechanism in Data Centers}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-430 %A Schwartz, Christian %A Pries, Rastin %A Tran-Gia, Phuoc %B International Conference on Information Networking (ICOIN) %C Bali, Indonesia %D 2012 %T A Queuing Analysis of an Energy-Saving Mechanism in Data Centers %X The high energy costs for running a data center led to a rethinking towards an energy-efficient operation of a data center. Designed for supporting the expected peak traffic load, the goal of the data center provider such as Amazon or Google is now to dynamically adapt the number of offered resources according to the current traffic load. In this paper, we present a queuing theoretical model to evaluate the trade-off between waiting time and power consumption if only a subset of servers is active all the time and the remaining servers are enabled on demand. We develop a queuing model with thresholds to turn-on reserve servers when needed. Furthermore, the resulting system behavior under varying parameters and requirements for Pareto optimality are studied.
• Prospects for Realizing User-Centric Network Orchestration: FEC-protected SVC Streaming. Zinner, Thomas; Liers, Florian; Hoßfeld, Tobias; Rauscher, Dirk; Reuther, Bernd; Günther, Daniel; Volkert, Thomas; Fiedler, Markus. In 7. GI/ITG KuVS Fachgespräch ’Future Internet’. München, 2012.
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  @inproceedings{info3-inproceedings-2012-436, address = {München}, author = {Zinner, Thomas and Liers, Florian and Hoßfeld, Tobias and Rauscher, Dirk and Reuther, Bernd and Günther, Daniel and Volkert, Thomas and Fiedler, Markus}, booktitle = {7. GI/ITG KuVS Fachgespräch 'Future Internet'}, keywords = {sys:hidden:inproceedings}, month = {01}, title = {Prospects for Realizing User-Centric Network Orchestration: FEC-protected SVC Streaming}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-436 %A Zinner, Thomas %A Liers, Florian %A Hoßfeld, Tobias %A Rauscher, Dirk %A Reuther, Bernd %A Günther, Daniel %A Volkert, Thomas %A Fiedler, Markus %B 7. GI/ITG KuVS Fachgespräch 'Future Internet' %C München %D 2012 %T Prospects for Realizing User-Centric Network Orchestration: FEC-protected SVC Streaming
• Parameters and Challenges for Virtual Network Embedding in the Future Internet. Stezenbach, David; Hartmann, Matthias; Tutschku, Kurt. In First IEEE Workshop on Algorithms and Operating Procedures for Federated Virtualized Networks (FEDNET2012) – Collocated with IEEE NOMS 2012. Maui, Hawaii, USA, 2012.
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  Recent developments in network science will facilitate the Internet as we know it today to integrate existing and upcoming technologies into a heterogeneous and highly dynamic resource pool. This enables the design of new applications and services which will form the Future Internet (FI). From this, many interesting prospects and unknown flexibility in terms of resource usage arise. In order to achieve this flexibility and make it usable for Service Providers (SPs) the FI will be build upon Virtual Networks (VNs) embedded into this resource pool. Furthermore, a closer interaction, resource sharing, and information exchange between providers, we refer to as Federation will be an enabler for this freedom of design. This allows the operation of heterogeneous and divergent services on the same physical infrastructure substrate. It is clear to see that all these upcoming possibilities offer new areas of research. In this work we structure the parameters required to describe resources and services accurately. Furthermore, we summarize research questions that need to be resolved in order to make the FI a story of success.

  @inproceedings{info3-inproceedings-2012-440, abstract = {Recent developments in network science will facilitate the Internet as we know it today to integrate existing and upcoming technologies into a heterogeneous and highly dynamic resource pool. This enables the design of new applications and services which will form the Future Internet (FI). From this, many interesting prospects and unknown flexibility in terms of resource usage arise. In order to achieve this flexibility and make it usable for Service Providers (SPs) the FI will be build upon Virtual Networks (VNs) embedded into this resource pool. Furthermore, a closer interaction, resource sharing, and information exchange between providers, we refer to as Federation will be an enabler for this freedom of design. This allows the operation of heterogeneous and divergent services on the same physical infrastructure substrate. It is clear to see that all these upcoming possibilities offer new areas of research. In this work we structure the parameters required to describe resources and services accurately. Furthermore, we summarize research questions that need to be resolved in order to make the FI a story of success.}, address = {Maui, Hawaii, USA}, author = {Stezenbach, David and Hartmann, Matthias and Tutschku, Kurt}, booktitle = {First IEEE Workshop on Algorithms and Operating Procedures for Federated Virtualized Networks (FEDNET2012) – Collocated with IEEE NOMS 2012}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Parameters and Challenges for Virtual Network Embedding in the Future Internet}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-440 %A Stezenbach, David %A Hartmann, Matthias %A Tutschku, Kurt %B First IEEE Workshop on Algorithms and Operating Procedures for Federated Virtualized Networks (FEDNET2012) – Collocated with IEEE NOMS 2012 %C Maui, Hawaii, USA %D 2012 %T Parameters and Challenges for Virtual Network Embedding in the Future Internet %X Recent developments in network science will facilitate the Internet as we know it today to integrate existing and upcoming technologies into a heterogeneous and highly dynamic resource pool. This enables the design of new applications and services which will form the Future Internet (FI). From this, many interesting prospects and unknown flexibility in terms of resource usage arise. In order to achieve this flexibility and make it usable for Service Providers (SPs) the FI will be build upon Virtual Networks (VNs) embedded into this resource pool. Furthermore, a closer interaction, resource sharing, and information exchange between providers, we refer to as Federation will be an enabler for this freedom of design. This allows the operation of heterogeneous and divergent services on the same physical infrastructure substrate. It is clear to see that all these upcoming possibilities offer new areas of research. In this work we structure the parameters required to describe resources and services accurately. Furthermore, we summarize research questions that need to be resolved in order to make the FI a story of success.
• Modeling and Evaluation of Address Resolution Scalability in VPLS. Klein, Dominik; Pries, Rastin; Scharf, Michael; Söllner, Michael; Menth, Michael. In IEEE ICC 2012 - Next-Generation Networking Symposium. Ottawa, Canada, 2012.
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  More and more services are provided by large data centers with a potentially very large number of physical or virtual hosts. As the number of hosted services and service consumers increases, also the number of hosts inside a data center raises to cope with the increasing end-user demand. Current data center networks are usually based on Ethernet and mechanisms like load balancing or redundancy between data centers require a transparent connection of these Ethernet networks over a Wide Area Network (WAN). Due to the large number of hosts, these interconnected data center networks face scalability problems on different protocol layers. One such issue, which is currently discussed within the IETF, is the scalability of the link layer Address Resolution Protocol (ARP). This paper studies the control traffic caused by address resolution for interconnected data centers. We develop an analytical model for the ARP traffic between data center locations that takes into account the number of hosts and connected sites. This model can then be used to quantify the ARP traffic for a data center interconnect solution. As an example, we apply our model to Virtual Private LAN Services (VPLS). In addition, we study how an ARP proxy can improve the overall scalability, and we show that a proxy significantly reduces the ARP traffic at VPLS switches.

  @inproceedings{info3-inproceedings-2012-434, abstract = {More and more services are provided by large data centers with a potentially very large number of physical or virtual hosts. As the number of hosted services and service consumers increases, also the number of hosts inside a data center raises to cope with the increasing end-user demand. Current data center networks are usually based on Ethernet and mechanisms like load balancing or redundancy between data centers require a transparent connection of these Ethernet networks over a Wide Area Network (WAN). Due to the large number of hosts, these interconnected data center networks face scalability problems on different protocol layers. One such issue, which is currently discussed within the IETF, is the scalability of the link layer Address Resolution Protocol (ARP). This paper studies the control traffic caused by address resolution for interconnected data centers. We develop an analytical model for the ARP traffic between data center locations that takes into account the number of hosts and connected sites. This model can then be used to quantify the ARP traffic for a data center interconnect solution. As an example, we apply our model to Virtual Private LAN Services (VPLS). In addition, we study how an ARP proxy can improve the overall scalability, and we show that a proxy significantly reduces the ARP traffic at VPLS switches.}, address = {Ottawa, Canada}, author = {Klein, Dominik and Pries, Rastin and Scharf, Michael and Söllner, Michael and Menth, Michael}, booktitle = {IEEE ICC 2012 - Next-Generation Networking Symposium}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Modeling and Evaluation of Address Resolution Scalability in VPLS}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-434 %A Klein, Dominik %A Pries, Rastin %A Scharf, Michael %A Söllner, Michael %A Menth, Michael %B IEEE ICC 2012 - Next-Generation Networking Symposium %C Ottawa, Canada %D 2012 %T Modeling and Evaluation of Address Resolution Scalability in VPLS %X More and more services are provided by large data centers with a potentially very large number of physical or virtual hosts. As the number of hosted services and service consumers increases, also the number of hosts inside a data center raises to cope with the increasing end-user demand. Current data center networks are usually based on Ethernet and mechanisms like load balancing or redundancy between data centers require a transparent connection of these Ethernet networks over a Wide Area Network (WAN). Due to the large number of hosts, these interconnected data center networks face scalability problems on different protocol layers. One such issue, which is currently discussed within the IETF, is the scalability of the link layer Address Resolution Protocol (ARP). This paper studies the control traffic caused by address resolution for interconnected data centers. We develop an analytical model for the ARP traffic between data center locations that takes into account the number of hosts and connected sites. This model can then be used to quantify the ARP traffic for a data center interconnect solution. As an example, we apply our model to Virtual Private LAN Services (VPLS). In addition, we study how an ARP proxy can improve the overall scalability, and we show that a proxy significantly reduces the ARP traffic at VPLS switches.
• Time is Bandwidth? Narrowing the Gap between Subjective Time Perception and Quality of Experience. Egger, Sebastian; Reichl, Peter; Hoßfeld, Tobias; Schatz, Raimund. In 2012 IEEE International Conference on Communications (ICC 2012). Ottawa, Canada, 2012.
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  Abstract—Over the last couple of years, the scope of Quality of Experience (QoE) research has been constantly extended, most recently to the field of Web QoE in the context of HTTP-based applications. In this paper, we address the question whether it is sufficient to reduce typical Web QoE assessment scenarios to the temporal aspects of waiting for task completion, which would allow to attribute the resulting logarithmic laws to well-known psychological insights on human time perception. We demonstrate that while this attribution is valid for simple waiting tasks which are typical for simple data services like e.g. file downloads, the case of interactive web browsing is much more complex. We show that this is not only because technical issues prevent bandwidth and download time from being directly correlated with each other in a simple manner, but also because user perceived web page load times strongly deviate from technical page load times. Consequently, existing approaches towards assessment and modeling of web browsing QoE have to be critically reviewed and redesigned.

  @inproceedings{info3-inproceedings-2012-433, abstract = {Abstract—Over the last couple of years, the scope of Quality of Experience (QoE) research has been constantly extended, most recently to the field of Web QoE in the context of HTTP-based applications. In this paper, we address the question whether it is sufficient to reduce typical Web QoE assessment scenarios to the temporal aspects of waiting for task completion, which would allow to attribute the resulting logarithmic laws to well-known psychological insights on human time perception. We demonstrate that while this attribution is valid for simple waiting tasks which are typical for simple data services like e.g. file downloads, the case of interactive web browsing is much more complex. We show that this is not only because technical issues prevent bandwidth and download time from being directly correlated with each other in a simple manner, but also because user perceived web page load times strongly deviate from technical page load times. Consequently, existing approaches towards assessment and modeling of web browsing QoE have to be critically reviewed and redesigned.}, address = {Ottawa, Canada}, author = {Egger, Sebastian and Reichl, Peter and Hoßfeld, Tobias and Schatz, Raimund}, booktitle = {2012 IEEE International Conference on Communications (ICC 2012)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Time is Bandwidth? Narrowing the Gap between Subjective Time Perception and Quality of Experience}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-433 %A Egger, Sebastian %A Reichl, Peter %A Hoßfeld, Tobias %A Schatz, Raimund %B 2012 IEEE International Conference on Communications (ICC 2012) %C Ottawa, Canada %D 2012 %T Time is Bandwidth? Narrowing the Gap between Subjective Time Perception and Quality of Experience %X Abstract—Over the last couple of years, the scope of Quality of Experience (QoE) research has been constantly extended, most recently to the field of Web QoE in the context of HTTP-based applications. In this paper, we address the question whether it is sufficient to reduce typical Web QoE assessment scenarios to the temporal aspects of waiting for task completion, which would allow to attribute the resulting logarithmic laws to well-known psychological insights on human time perception. We demonstrate that while this attribution is valid for simple waiting tasks which are typical for simple data services like e.g. file downloads, the case of interactive web browsing is much more complex. We show that this is not only because technical issues prevent bandwidth and download time from being directly correlated with each other in a simple manner, but also because user perceived web page load times strongly deviate from technical page load times. Consequently, existing approaches towards assessment and modeling of web browsing QoE have to be critically reviewed and redesigned.
• Enabling Experiments for Energy-Efficient Data Center Networks on OpenFlow-based Platform. Huu Thanh, Nguyen; Nam, Pham; Thu Truong, Huong; Tai Hung, Nguyen; Pries, Rastin. In 4th International Conference on Communications and Electronics (ICCE 12). Hué, Vietnam, 2012.
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  @inproceedings{info3-inproceedings-2012-446, address = {Hué, Vietnam}, author = {Huu Thanh, Nguyen and Nam, Pham and Thu Truong, Huong and Tai Hung, Nguyen and Pries, Rastin}, booktitle = {4th International Conference on Communications and Electronics (ICCE 12)}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Enabling Experiments for Energy-Efficient Data Center Networks on OpenFlow-based Platform}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-446 %A Huu Thanh, Nguyen %A Nam, Pham %A Thu Truong, Huong %A Tai Hung, Nguyen %A Pries, Rastin %B 4th International Conference on Communications and Electronics (ICCE 12) %C Hué, Vietnam %D 2012 %T Enabling Experiments for Energy-Efficient Data Center Networks on OpenFlow-based Platform
• A Flexible OpenFlow-Controller Benchmark. Jarschel, Michael; Lehrieder, Frank; Magyari, Zsolt; Pries, Rastin. In 1st European Workshop on Software Defined Networks (EWSDN 2012). Darmstadt, Germany, 2012.
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  Software defined networking (SDN) promises a way to more flexible networks that can adapt to changing demands. At the same time these networks should also benefit from simpler management mechanisms. This is achieved by moving the network control out of the forwarding devices to purpose-tailored software-applications on top of a ”networking operating system”. Currently, the most notable representative of this approach is OpenFlow. In the OpenFlow architecture the operating system is represented by the OpenFlow controller. As the key component of the OpenFlow ecosystem, the behavior and performance of the controller are significant for the entire network. Therefore, it is important to understand these influence factors, when planning an OpenFlow-based SDN deployment. In this work, we introduce a tool to help achieving just that - a flexible OpenFlow controller benchmark. The benchmark creates a set of message-generating virtual switches, which can be configured independently from each other to emulate a certain scenario and also keep their own statistics. This way a granular controller performance analysis is possible.

  @inproceedings{info3-inproceedings-2012-455, abstract = {Software defined networking (SDN) promises a way to more flexible networks that can adapt to changing demands. At the same time these networks should also benefit from simpler management mechanisms. This is achieved by moving the network control out of the forwarding devices to purpose-tailored software-applications on top of a ”networking operating system”. Currently, the most notable representative of this approach is OpenFlow. In the OpenFlow architecture the operating system is represented by the OpenFlow controller. As the key component of the OpenFlow ecosystem, the behavior and performance of the controller are significant for the entire network. Therefore, it is important to understand these influence factors, when planning an OpenFlow-based SDN deployment. In this work, we introduce a tool to help achieving just that - a flexible OpenFlow controller benchmark. The benchmark creates a set of message-generating virtual switches, which can be configured independently from each other to emulate a certain scenario and also keep their own statistics. This way a granular controller performance analysis is possible.}, address = {Darmstadt, Germany}, author = {Jarschel, Michael and Lehrieder, Frank and Magyari, Zsolt and Pries, Rastin}, booktitle = {1st European Workshop on Software Defined Networks (EWSDN 2012)}, keywords = {openflow}, month = 10, title = {A Flexible OpenFlow-Controller Benchmark}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-455 %A Jarschel, Michael %A Lehrieder, Frank %A Magyari, Zsolt %A Pries, Rastin %B 1st European Workshop on Software Defined Networks (EWSDN 2012) %C Darmstadt, Germany %D 2012 %T A Flexible OpenFlow-Controller Benchmark %X Software defined networking (SDN) promises a way to more flexible networks that can adapt to changing demands. At the same time these networks should also benefit from simpler management mechanisms. This is achieved by moving the network control out of the forwarding devices to purpose-tailored software-applications on top of a ”networking operating system”. Currently, the most notable representative of this approach is OpenFlow. In the OpenFlow architecture the operating system is represented by the OpenFlow controller. As the key component of the OpenFlow ecosystem, the behavior and performance of the controller are significant for the entire network. Therefore, it is important to understand these influence factors, when planning an OpenFlow-based SDN deployment. In this work, we introduce a tool to help achieving just that - a flexible OpenFlow controller benchmark. The benchmark creates a set of message-generating virtual switches, which can be configured independently from each other to emulate a certain scenario and also keep their own statistics. This way a granular controller performance analysis is possible.
• Performance Optimization in Access Networks Using a Combined Control Strategy. Wamser, Florian; Hock, David; Seufert, Michael; Pries, Rastin; Tran-Gia, Phuoc. In 12th Würzburg Workshop on IP: ITG Workshop ’Visions of Future Generation Networks’ (Euroview). Würzburg, Germany, 2012.
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  @inproceedings{info3-inproceedings-2012-454, address = {Würzburg, Germany}, author = {Wamser, Florian and Hock, David and Seufert, Michael and Pries, Rastin and Tran-Gia, Phuoc}, booktitle = {12th Würzburg Workshop on IP: ITG Workshop 'Visions of Future Generation Networks' (Euroview)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Performance Optimization in Access Networks Using a Combined Control Strategy}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-454 %A Wamser, Florian %A Hock, David %A Seufert, Michael %A Pries, Rastin %A Tran-Gia, Phuoc %B 12th Würzburg Workshop on IP: ITG Workshop 'Visions of Future Generation Networks' (Euroview) %C Würzburg, Germany %D 2012 %T Performance Optimization in Access Networks Using a Combined Control Strategy
• Initial Delay vs. Interruptions: Between the Devil and the Deep Blue Sea. Hoßfeld, Tobias; Egger, Sebastian; Schatz, Raimund; Fiedler, Markus; Masuch, Kathrin; Lorentzen, Charlott. In QoMEX 2012. Yarra Valley, Australia, 2012.
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  End user quality perception in the context of Internet applications and services is often characterized by waiting times before service consumption as well as interruptions during service consumption. In particular in case of bad network conditions, network and service providers have to trade off between these two impairment types, i.e. between the devil and the deep blue sea. In this paper we investigate this trade-off in order to guide the design and development of Internet applications and network management approaches. The contribution of this paper is twofold. Firstly, we quantify the impact of initial delays on the user perceived Quality of Experience (QoE) for different application scenarios by means of subjective laboratory and crowdsourcing studies. We show that QoE for a given waiting time strongly depends on the concrete application at hand but that rating diversity remains fairly application-invariant. Secondly, using the example of YouTube video streaming we compare the influence of initial delays and interruptions (stallings) during watching. Our results demonstrate that users are extremely sensitive to interruptions and that services should be designed accordingly e.g. by increasing initial delay for prebuffering to overcome lack of resources.

  @inproceedings{info3-inproceedings-2012-444, abstract = {End user quality perception in the context of Internet applications and services is often characterized by waiting times before service consumption as well as interruptions during service consumption. In particular in case of bad network conditions, network and service providers have to trade off between these two impairment types, i.e. between the devil and the deep blue sea. In this paper we investigate this trade-off in order to guide the design and development of Internet applications and network management approaches. The contribution of this paper is twofold. Firstly, we quantify the impact of initial delays on the user perceived Quality of Experience (QoE) for different application scenarios by means of subjective laboratory and crowdsourcing studies. We show that QoE for a given waiting time strongly depends on the concrete application at hand but that rating diversity remains fairly application-invariant. Secondly, using the example of YouTube video streaming we compare the influence of initial delays and interruptions (stallings) during watching. Our results demonstrate that users are extremely sensitive to interruptions and that services should be designed accordingly e.g. by increasing initial delay for prebuffering to overcome lack of resources.}, address = {Yarra Valley, Australia}, author = {Hoßfeld, Tobias and Egger, Sebastian and Schatz, Raimund and Fiedler, Markus and Masuch, Kathrin and Lorentzen, Charlott}, booktitle = {QoMEX 2012}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Initial Delay vs. Interruptions: Between the Devil and the Deep Blue Sea}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-444 %A Hoßfeld, Tobias %A Egger, Sebastian %A Schatz, Raimund %A Fiedler, Markus %A Masuch, Kathrin %A Lorentzen, Charlott %B QoMEX 2012 %C Yarra Valley, Australia %D 2012 %T Initial Delay vs. Interruptions: Between the Devil and the Deep Blue Sea %X End user quality perception in the context of Internet applications and services is often characterized by waiting times before service consumption as well as interruptions during service consumption. In particular in case of bad network conditions, network and service providers have to trade off between these two impairment types, i.e. between the devil and the deep blue sea. In this paper we investigate this trade-off in order to guide the design and development of Internet applications and network management approaches. The contribution of this paper is twofold. Firstly, we quantify the impact of initial delays on the user perceived Quality of Experience (QoE) for different application scenarios by means of subjective laboratory and crowdsourcing studies. We show that QoE for a given waiting time strongly depends on the concrete application at hand but that rating diversity remains fairly application-invariant. Secondly, using the example of YouTube video streaming we compare the influence of initial delays and interruptions (stallings) during watching. Our results demonstrate that users are extremely sensitive to interruptions and that services should be designed accordingly e.g. by increasing initial delay for prebuffering to overcome lack of resources.
• Waiting Times in Quality of Experience for Web Based Services. Egger, Sebastian; Hoßfeld, Tobias; Schatz, Raimund; Fiedler, Markus. In QoMEX 2012. Yarra Valley, Australia, 2012.
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  A considerable share of applications such as web or e-mail browsing, online picture viewing and file downloads imply waiting times for their users, which is due to the turn-taking of information requests by the user and correspoding response times until each request is fulfilled. Thus, end-user quality perception in the context of interactive data services is dominated by waiting times; the longer the latter, the less satisfied the user becomes. As opposed to heavily researched multimedia experience, perception of waiting times is still not strongly explored in the context of Quality of Experience (QoE). This tutorial will contribute to closing this gap. In its first part, it addresses perception principles and discusses their applicability towards fundamental relationships between waiting times and resulting QoE. It then investigates to which extent the same relationships can also be used to describe QoE for more complex services such as web browsing. Finally, it discusses applications where waiting times determine QoE, amongst other factors. For example, the past shift from UDP media streaming to TCP media streaming (e.g. youtube.com) has extended the relevance of waiting times also to the domain of online video services. In particular, user-perceived quality suffers from initial delays when applications are launched, as well as from freezes during the delivery of the stream. These aspects, which have to be traded against each other to some extent, will be discussed mainly for HTTP video streaming in the last part of this tutorial.

  @inproceedings{info3-inproceedings-2012-452, abstract = {A considerable share of applications such as web or e-mail browsing, online picture viewing and file downloads imply waiting times for their users, which is due to the turn-taking of information requests by the user and correspoding response times until each request is fulfilled. Thus, end-user quality perception in the context of interactive data services is dominated by waiting times; the longer the latter, the less satisfied the user becomes. As opposed to heavily researched multimedia experience, perception of waiting times is still not strongly explored in the context of Quality of Experience (QoE). This tutorial will contribute to closing this gap. In its first part, it addresses perception principles and discusses their applicability towards fundamental relationships between waiting times and resulting QoE. It then investigates to which extent the same relationships can also be used to describe QoE for more complex services such as web browsing. Finally, it discusses applications where waiting times determine QoE, amongst other factors. For example, the past shift from UDP media streaming to TCP media streaming (e.g. youtube.com) has extended the relevance of waiting times also to the domain of online video services. In particular, user-perceived quality suffers from initial delays when applications are launched, as well as from freezes during the delivery of the stream. These aspects, which have to be traded against each other to some extent, will be discussed mainly for HTTP video streaming in the last part of this tutorial.}, address = {Yarra Valley, Australia}, author = {Egger, Sebastian and Hoßfeld, Tobias and Schatz, Raimund and Fiedler, Markus}, booktitle = {QoMEX 2012}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Waiting Times in Quality of Experience for Web Based Services}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-452 %A Egger, Sebastian %A Hoßfeld, Tobias %A Schatz, Raimund %A Fiedler, Markus %B QoMEX 2012 %C Yarra Valley, Australia %D 2012 %T Waiting Times in Quality of Experience for Web Based Services %X A considerable share of applications such as web or e-mail browsing, online picture viewing and file downloads imply waiting times for their users, which is due to the turn-taking of information requests by the user and correspoding response times until each request is fulfilled. Thus, end-user quality perception in the context of interactive data services is dominated by waiting times; the longer the latter, the less satisfied the user becomes. As opposed to heavily researched multimedia experience, perception of waiting times is still not strongly explored in the context of Quality of Experience (QoE). This tutorial will contribute to closing this gap. In its first part, it addresses perception principles and discusses their applicability towards fundamental relationships between waiting times and resulting QoE. It then investigates to which extent the same relationships can also be used to describe QoE for more complex services such as web browsing. Finally, it discusses applications where waiting times determine QoE, amongst other factors. For example, the past shift from UDP media streaming to TCP media streaming (e.g. youtube.com) has extended the relevance of waiting times also to the domain of online video services. In particular, user-perceived quality suffers from initial delays when applications are launched, as well as from freezes during the delivery of the stream. These aspects, which have to be traded against each other to some extent, will be discussed mainly for HTTP video streaming in the last part of this tutorial.
• Passive YouTube QoE Monitoring for ISPs. Schatz, Raimund; Hoßfeld, Tobias; Casas, Pedro. In Best Paper Award at Workshop on Future Internet and Next Generation Networks (FINGNet-2012). Palermo, Italy, 2012.
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  Over last decade, Quality of Experience (QoE) has become the guiding paradigm for enabling a more usercentric understanding of quality of communication networks and services. The intensifying competition among ISPs and the exponentially increasing traffic volumes caused by online video platforms like YouTube is forcing service providers to integrate QoE into their corporate DNA. This paper investigates the problem of YouTube QoE monitoring from an access provider’s perspective. To this end, we present three novel methods for in-network measurement of the QoE impairment that dominates user perception in the context of HTTP video-streaming: stalling of playback. Our evaluation results show that it is possible to detect applicationlevel stalling events at high accuracy by using network-level passive probing only. However, only the most complex and most accurate approach can be used for QoE prediction due to the non-linearities inherent in human quality perception.

  @inproceedings{info3-inproceedings-2012-437, abstract = {Over last decade, Quality of Experience (QoE) has become the guiding paradigm for enabling a more usercentric understanding of quality of communication networks and services. The intensifying competition among ISPs and the exponentially increasing traffic volumes caused by online video platforms like YouTube is forcing service providers to integrate QoE into their corporate DNA. This paper investigates the problem of YouTube QoE monitoring from an access provider’s perspective. To this end, we present three novel methods for in-network measurement of the QoE impairment that dominates user perception in the context of HTTP video-streaming: stalling of playback. Our evaluation results show that it is possible to detect applicationlevel stalling events at high accuracy by using network-level passive probing only. However, only the most complex and most accurate approach can be used for QoE prediction due to the non-linearities inherent in human quality perception.}, address = {Palermo, Italy}, author = {Schatz, Raimund and Hoßfeld, Tobias and Casas, Pedro}, booktitle = {Best Paper Award at Workshop on Future Internet and Next Generation Networks (FINGNet-2012)}, keywords = {demobenefit}, month = {07}, title = {Passive YouTube QoE Monitoring for ISPs}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-437 %A Schatz, Raimund %A Hoßfeld, Tobias %A Casas, Pedro %B Best Paper Award at Workshop on Future Internet and Next Generation Networks (FINGNet-2012) %C Palermo, Italy %D 2012 %T Passive YouTube QoE Monitoring for ISPs %X Over last decade, Quality of Experience (QoE) has become the guiding paradigm for enabling a more usercentric understanding of quality of communication networks and services. The intensifying competition among ISPs and the exponentially increasing traffic volumes caused by online video platforms like YouTube is forcing service providers to integrate QoE into their corporate DNA. This paper investigates the problem of YouTube QoE monitoring from an access provider’s perspective. To this end, we present three novel methods for in-network measurement of the QoE impairment that dominates user perception in the context of HTTP video-streaming: stalling of playback. Our evaluation results show that it is possible to detect applicationlevel stalling events at high accuracy by using network-level passive probing only. However, only the most complex and most accurate approach can be used for QoE prediction due to the non-linearities inherent in human quality perception.
• Microworkers vs. Facebook: The Impact of Crowdsourcing Platform Choice on Experimental Results. Gardlo, Bruno; Ries, Michal; Hoßfeld, Tobias; Schatz, Raimund. In QoMEX 2012. Yarra Valley, Australia, 2012.
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  Subjective laboratory tests represent a proven, reliable approach towards multimedia quality assessment. Nonetheless, in certain cases novel progressive quality of experience (QoE) assessment methods can lead to better results or enable test execution in more cost-effective ways. In this respect, crowdsourcing can be considered as emerging method enabling researchers to better explore end-user quality perception when requiring a large panel of subjects, particularly for Web application usage scenarios. However, the crowdsourcing platform chosen for recruiting participants can have an impact on the experimental results. In this paper, we examine the platform’s influence on QoE results by comparing MOS scores of two otherwise identical subjective HD video quality experiments executed on one paid and one non-paid crowdsourcing platform.

  @inproceedings{info3-inproceedings-2012-448, abstract = {Subjective laboratory tests represent a proven, reliable approach towards multimedia quality assessment. Nonetheless, in certain cases novel progressive quality of experience (QoE) assessment methods can lead to better results or enable test execution in more cost-effective ways. In this respect, crowdsourcing can be considered as emerging method enabling researchers to better explore end-user quality perception when requiring a large panel of subjects, particularly for Web application usage scenarios. However, the crowdsourcing platform chosen for recruiting participants can have an impact on the experimental results. In this paper, we examine the platform’s influence on QoE results by comparing MOS scores of two otherwise identical subjective HD video quality experiments executed on one paid and one non-paid crowdsourcing platform.}, address = {Yarra Valley, Australia}, author = {Gardlo, Bruno and Ries, Michal and Hoßfeld, Tobias and Schatz, Raimund}, booktitle = {QoMEX 2012}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Microworkers vs. Facebook: The Impact of Crowdsourcing Platform Choice on Experimental Results}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-448 %A Gardlo, Bruno %A Ries, Michal %A Hoßfeld, Tobias %A Schatz, Raimund %B QoMEX 2012 %C Yarra Valley, Australia %D 2012 %T Microworkers vs. Facebook: The Impact of Crowdsourcing Platform Choice on Experimental Results %X Subjective laboratory tests represent a proven, reliable approach towards multimedia quality assessment. Nonetheless, in certain cases novel progressive quality of experience (QoE) assessment methods can lead to better results or enable test execution in more cost-effective ways. In this respect, crowdsourcing can be considered as emerging method enabling researchers to better explore end-user quality perception when requiring a large panel of subjects, particularly for Web application usage scenarios. However, the crowdsourcing platform chosen for recruiting participants can have an impact on the experimental results. In this paper, we examine the platform’s influence on QoE results by comparing MOS scores of two otherwise identical subjective HD video quality experiments executed on one paid and one non-paid crowdsourcing platform.
• Wikipedia and its Network of Authors from a Social Network Perspective. Hirth, Matthias; Lehrieder, Frank; Oberste-Vorth, Stephan; Hoßfeld, Tobias; Tran-Gia, Phuoc. In International Conference on Communications and Electronics (ICCE). Hue, Vietnam, 2012.
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  Online social networks (OSNs) become more and more important in today's social and business life. Therefore, considerable effort is put in research to gain a deeper knowledge of the development of these networks and their dynamics. However, most of the existing literature is based on very limited subsets of the network data, which is often filtered by the OSN operator providing the data or biased by the crawling mechanisms used to obtain the data. This makes it difficult to analyze the temporal evolution of OSNs based on complete data. To overcome this issue, we investigate the dynamics of the publicly available collaboration network of the Wikipedia authors as an example for an OSN-like network. In particular, we study the temporal evolution of this network since its beginning and demonstrate that it exhibits prominent similarities to well known social networks such as the small-world phenomenon. This indicates that the insights gained from the analysis of Wikipedia's collaboration network might be transferable to social networks in general.

  @inproceedings{info3-inproceedings-2012-450, abstract = {Online social networks (OSNs) become more and more important in today's social and business life. Therefore, considerable effort is put in research to gain a deeper knowledge of the development of these networks and their dynamics. However, most of the existing literature is based on very limited subsets of the network data, which is often filtered by the OSN operator providing the data or biased by the crawling mechanisms used to obtain the data. This makes it difficult to analyze the temporal evolution of OSNs based on complete data. To overcome this issue, we investigate the dynamics of the publicly available collaboration network of the Wikipedia authors as an example for an OSN-like network. In particular, we study the temporal evolution of this network since its beginning and demonstrate that it exhibits prominent similarities to well known social networks such as the small-world phenomenon. This indicates that the insights gained from the analysis of Wikipedia's collaboration network might be transferable to social networks in general.}, address = {Hue, Vietnam}, author = {Hirth, Matthias and Lehrieder, Frank and Oberste-Vorth, Stephan and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {International Conference on Communications and Electronics (ICCE)}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Wikipedia and its Network of Authors from a Social Network Perspective}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-450 %A Hirth, Matthias %A Lehrieder, Frank %A Oberste-Vorth, Stephan %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B International Conference on Communications and Electronics (ICCE) %C Hue, Vietnam %D 2012 %T Wikipedia and its Network of Authors from a Social Network Perspective %X Online social networks (OSNs) become more and more important in today's social and business life. Therefore, considerable effort is put in research to gain a deeper knowledge of the development of these networks and their dynamics. However, most of the existing literature is based on very limited subsets of the network data, which is often filtered by the OSN operator providing the data or biased by the crawling mechanisms used to obtain the data. This makes it difficult to analyze the temporal evolution of OSNs based on complete data. To overcome this issue, we investigate the dynamics of the publicly available collaboration network of the Wikipedia authors as an example for an OSN-like network. In particular, we study the temporal evolution of this network since its beginning and demonstrate that it exhibits prominent similarities to well known social networks such as the small-world phenomenon. This indicates that the insights gained from the analysis of Wikipedia's collaboration network might be transferable to social networks in general.
• Evaluating the Trade-Off Between Energy-Efficiency and QoE in Wireless Mesh Networks. Hock, David; Bernardo, Vitor; Zinner, Thomas; Wamser, Florian; Hummel, Karin A.; Curado, Marilia; Pries, Rastin; Braun, Torsten; Tran-Gia, Phuoc. In 4th International Conference on Communications and Electronics (ICCE 12). Hué, Vietnam, 2012.
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  @inproceedings{info3-inproceedings-2012-447, address = {Hué, Vietnam}, author = {Hock, David and Bernardo, Vitor and Zinner, Thomas and Wamser, Florian and Hummel, Karin A. and Curado, Marilia and Pries, Rastin and Braun, Torsten and Tran-Gia, Phuoc}, booktitle = {4th International Conference on Communications and Electronics (ICCE 12)}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Evaluating the Trade-Off Between Energy-Efficiency and QoE in Wireless Mesh Networks}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-447 %A Hock, David %A Bernardo, Vitor %A Zinner, Thomas %A Wamser, Florian %A Hummel, Karin A. %A Curado, Marilia %A Pries, Rastin %A Braun, Torsten %A Tran-Gia, Phuoc %B 4th International Conference on Communications and Electronics (ICCE 12) %C Hué, Vietnam %D 2012 %T Evaluating the Trade-Off Between Energy-Efficiency and QoE in Wireless Mesh Networks
• Utilizing Buffered YouTube Playtime for QoE-oriented Scheduling in OFDMA Networks. Wamser, Florian; Staehle, Dirk; Prokopec, Jan; Mäder, Andreas; Tran-Gia, Phuoc. In International Teletraffic Congress (ITC). Kraków, Poland, 2012.
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  With the introduction of 4th generation mobile networks, applications such as high-quality video streaming to the end user becomes possible. However, the expected demand for such services outpaces the capacity increase of the networks. Since there is mostly a capacity bottleneck in the air interface between a base station and user equipment, one of the main challenges for radio resource management is therefore to enforce precise quality guarantees for users with high expectations on service quality. We consider, in this paper, an OFDMA access network with YouTube users, and address the challenge of improving the quality of experience (QoE) of a dedicated user by utilizing the buffered playtime of a YouTube video for scheduling. The advantage of this approach is that scheduling is done according to the instantaneous throughput requirement of the end user application, and not by the network by maintaining average quality-of-service (QoS) parameters. The paper describes the concept and provides a simulative evaluation of the approach in an LTE network to demonstrate the benefits.

  @inproceedings{info3-inproceedings-2012-449, abstract = {With the introduction of 4th generation mobile networks, applications such as high-quality video streaming to the end user becomes possible. However, the expected demand for such services outpaces the capacity increase of the networks. Since there is mostly a capacity bottleneck in the air interface between a base station and user equipment, one of the main challenges for radio resource management is therefore to enforce precise quality guarantees for users with high expectations on service quality. We consider, in this paper, an OFDMA access network with YouTube users, and address the challenge of improving the quality of experience (QoE) of a dedicated user by utilizing the buffered playtime of a YouTube video for scheduling. The advantage of this approach is that scheduling is done according to the instantaneous throughput requirement of the end user application, and not by the network by maintaining average quality-of-service (QoS) parameters. The paper describes the concept and provides a simulative evaluation of the approach in an LTE network to demonstrate the benefits.}, address = {Kraków, Poland}, author = {Wamser, Florian and Staehle, Dirk and Prokopec, Jan and Mäder, Andreas and Tran-Gia, Phuoc}, booktitle = {International Teletraffic Congress (ITC)}, keywords = {demobenefit}, month = {09}, title = {Utilizing Buffered YouTube Playtime for QoE-oriented Scheduling in OFDMA Networks}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-449 %A Wamser, Florian %A Staehle, Dirk %A Prokopec, Jan %A Mäder, Andreas %A Tran-Gia, Phuoc %B International Teletraffic Congress (ITC) %C Kraków, Poland %D 2012 %T Utilizing Buffered YouTube Playtime for QoE-oriented Scheduling in OFDMA Networks %X With the introduction of 4th generation mobile networks, applications such as high-quality video streaming to the end user becomes possible. However, the expected demand for such services outpaces the capacity increase of the networks. Since there is mostly a capacity bottleneck in the air interface between a base station and user equipment, one of the main challenges for radio resource management is therefore to enforce precise quality guarantees for users with high expectations on service quality. We consider, in this paper, an OFDMA access network with YouTube users, and address the challenge of improving the quality of experience (QoE) of a dedicated user by utilizing the buffered playtime of a YouTube video for scheduling. The advantage of this approach is that scheduling is done according to the instantaneous throughput requirement of the end user application, and not by the network by maintaining average quality-of-service (QoS) parameters. The paper describes the concept and provides a simulative evaluation of the approach in an LTE network to demonstrate the benefits.
• User-Centric Network-Application Interaction for Live HD Video Streaming. Zinner, Thomas; Klein, Dominik; Hoßfeld, Tobias. In 4th International Conference on Mobile Networks and Management (MONAMI 2012). Hamburg, Germany, 2012.
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  Applications and resource allocation within the network become more and more exible in supporting divergent user demands. This is re ected by state-of-the-art video codecs like H.264/SVC which allow a dynamic adaptation of the video quality and therewith the required network resources. Within the network, techniques like network virtualization and multipath data transport allow exible allocation of network resources based on application demands. This paper outlines the potential of the interaction between application and network with an example of a scalable video streaming service and a multipath transport network.

  @inproceedings{info3-inproceedings-2012-456, abstract = {Applications and resource allocation within the network become more and more exible in supporting divergent user demands. This is re ected by state-of-the-art video codecs like H.264/SVC which allow a dynamic adaptation of the video quality and therewith the required network resources. Within the network, techniques like network virtualization and multipath data transport allow exible allocation of network resources based on application demands. This paper outlines the potential of the interaction between application and network with an example of a scalable video streaming service and a multipath transport network.}, address = {Hamburg, Germany}, author = {Zinner, Thomas and Klein, Dominik and Hoßfeld, Tobias}, booktitle = {4th International Conference on Mobile Networks and Management (MONAMI 2012)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {User-Centric Network-Application Interaction for Live HD Video Streaming}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-456 %A Zinner, Thomas %A Klein, Dominik %A Hoßfeld, Tobias %B 4th International Conference on Mobile Networks and Management (MONAMI 2012) %C Hamburg, Germany %D 2012 %T User-Centric Network-Application Interaction for Live HD Video Streaming %X Applications and resource allocation within the network become more and more exible in supporting divergent user demands. This is re ected by state-of-the-art video codecs like H.264/SVC which allow a dynamic adaptation of the video quality and therewith the required network resources. Within the network, techniques like network virtualization and multipath data transport allow exible allocation of network resources based on application demands. This paper outlines the potential of the interaction between application and network with an example of a scalable video streaming service and a multipath transport network.
• Who Profits from Peer-to-Peer File-Sharing? Traffic Optimization Potential in BitTorrent Swarms. Burger, Valentin; Lehrieder, Frank; Hoßfeld, Tobias; Seedorf, Jan. In International Teletraffic Congress (ITC 24). Krakow, Poland, 2012.
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  BitTorrent-based peer-to-peer networks constitute a significant share of Internet traffic. Therefore, the IETF working group on application layer traffic optimization (ALTO) discusses several approaches for guiding the BitTorrent traffic that aim at reducing the large amount of inter-ISP traffic costs caused by these networks. However, performance evaluations of these approaches are mostly limited to artificial scenarios that do not take into account the real Internet topology with its inter-ISP relationships and the actual distribution of BitTorrent users across autonomous systems (AS). In this study, we use measurements of the distribution of a large number of live BitTorrent networks and combine them with the AS-level Internet topology provided by Caida.org. Based on this data, we estimate in which tier of the Internet hierarchy BitTorrent traffic is mainly located and how much optimization potential exists for the different types of ISPs. Therewith, traffic flow and revenue implications of guiding Internet-wide BitTorrent swarms are analyzed. Our results show that tier-1 ISPs profit from the un-managed exchange of peer-to-peer traffic and that these profits significantly decrease when the other ISPs would apply ALTO solutions.

  @inproceedings{info3-inproceedings-2012-451, abstract = {BitTorrent-based peer-to-peer networks constitute a significant share of Internet traffic. Therefore, the IETF working group on application layer traffic optimization (ALTO) discusses several approaches for guiding the BitTorrent traffic that aim at reducing the large amount of inter-ISP traffic costs caused by these networks. However, performance evaluations of these approaches are mostly limited to artificial scenarios that do not take into account the real Internet topology with its inter-ISP relationships and the actual distribution of BitTorrent users across autonomous systems (AS). In this study, we use measurements of the distribution of a large number of live BitTorrent networks and combine them with the AS-level Internet topology provided by Caida.org. Based on this data, we estimate in which tier of the Internet hierarchy BitTorrent traffic is mainly located and how much optimization potential exists for the different types of ISPs. Therewith, traffic flow and revenue implications of guiding Internet-wide BitTorrent swarms are analyzed. Our results show that tier-1 ISPs profit from the un-managed exchange of peer-to-peer traffic and that these profits significantly decrease when the other ISPs would apply ALTO solutions.}, address = {Krakow, Poland}, author = {Burger, Valentin and Lehrieder, Frank and Hoßfeld, Tobias and Seedorf, Jan}, booktitle = {International Teletraffic Congress (ITC 24)}, keywords = {oekonet}, month = {09}, title = {Who Profits from Peer-to-Peer File-Sharing? Traffic Optimization Potential in BitTorrent Swarms}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-451 %A Burger, Valentin %A Lehrieder, Frank %A Hoßfeld, Tobias %A Seedorf, Jan %B International Teletraffic Congress (ITC 24) %C Krakow, Poland %D 2012 %T Who Profits from Peer-to-Peer File-Sharing? Traffic Optimization Potential in BitTorrent Swarms %X BitTorrent-based peer-to-peer networks constitute a significant share of Internet traffic. Therefore, the IETF working group on application layer traffic optimization (ALTO) discusses several approaches for guiding the BitTorrent traffic that aim at reducing the large amount of inter-ISP traffic costs caused by these networks. However, performance evaluations of these approaches are mostly limited to artificial scenarios that do not take into account the real Internet topology with its inter-ISP relationships and the actual distribution of BitTorrent users across autonomous systems (AS). In this study, we use measurements of the distribution of a large number of live BitTorrent networks and combine them with the AS-level Internet topology provided by Caida.org. Based on this data, we estimate in which tier of the Internet hierarchy BitTorrent traffic is mainly located and how much optimization potential exists for the different types of ISPs. Therewith, traffic flow and revenue implications of guiding Internet-wide BitTorrent swarms are analyzed. Our results show that tier-1 ISPs profit from the un-managed exchange of peer-to-peer traffic and that these profits significantly decrease when the other ISPs would apply ALTO solutions.
• Intra-Mesh Congestion Control for IEEE 802.11s Wireless Mesh Networks. Staehle, Barbara; Bahr, Michael; Fu, Desheng; Staehle, Dirk. In International Conference on Computer and Communication Networks 2012 (ICCCN 2012). Munich, Germany, 2012.
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  @inproceedings{info3-inproceedings-2012-453, address = {Munich, Germany}, author = {Staehle, Barbara and Bahr, Michael and Fu, Desheng and Staehle, Dirk}, booktitle = {International Conference on Computer and Communication Networks 2012 (ICCCN 2012)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Intra-Mesh Congestion Control for IEEE 802.11s Wireless Mesh Networks}, year = 2012 }

  %0 Conference Paper %1 info3-inproceedings-2012-453 %A Staehle, Barbara %A Bahr, Michael %A Fu, Desheng %A Staehle, Dirk %B International Conference on Computer and Communication Networks 2012 (ICCCN 2012) %C Munich, Germany %D 2012 %T Intra-Mesh Congestion Control for IEEE 802.11s Wireless Mesh Networks

• An Evaluation of QoE in Cloud Gaming Based on Subjective Tests. Jarschel, Michael; Schlosser, Daniel; Scheuring, Sven; Hoßfeld, Tobias. In Workshop on Future Internet and Next Generation Networks (FINGNet-2011). Seoul, Korea, 2011.
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  Cloud Gaming is a new kind of service, which combines the successful concepts of Cloud Computing and Online Gaming. It provides the entire game experience to the users remotely from a data center. The player is no longer dependent on a specific type or quality of gaming hardware, but is able to use common devices. The end device only needs a broadband internet connection and the ability to display High Definition (HD) video. While this may reduce hardware costs for users and increase the revenue for developers by leaving out the retail chain, it also raises new challenges for service quality in terms of bandwidth and latency for the underlying network. In this paper we present the results of a subjective user study we conducted into the user-perceived quality of experience (QoE) in Cloud Gaming. We design a measurement environment, that emulates this new type of service, define tests for users to assess the QoE, derive Key Influence Factors (KFI) and influences of content and perception from our results.

  @inproceedings{info3-inproceedings-2011-411, abstract = {Cloud Gaming is a new kind of service, which combines the successful concepts of Cloud Computing and Online Gaming. It provides the entire game experience to the users remotely from a data center. The player is no longer dependent on a specific type or quality of gaming hardware, but is able to use common devices. The end device only needs a broadband internet connection and the ability to display High Definition (HD) video. While this may reduce hardware costs for users and increase the revenue for developers by leaving out the retail chain, it also raises new challenges for service quality in terms of bandwidth and latency for the underlying network. In this paper we present the results of a subjective user study we conducted into the user-perceived quality of experience (QoE) in Cloud Gaming. We design a measurement environment, that emulates this new type of service, define tests for users to assess the QoE, derive Key Influence Factors (KFI) and influences of content and perception from our results.}, address = {Seoul, Korea}, author = {Jarschel, Michael and Schlosser, Daniel and Scheuring, Sven and Hoßfeld, Tobias}, booktitle = {Workshop on Future Internet and Next Generation Networks (FINGNet-2011)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {An Evaluation of QoE in Cloud Gaming Based on Subjective Tests}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-411 %A Jarschel, Michael %A Schlosser, Daniel %A Scheuring, Sven %A Hoßfeld, Tobias %B Workshop on Future Internet and Next Generation Networks (FINGNet-2011) %C Seoul, Korea %D 2011 %T An Evaluation of QoE in Cloud Gaming Based on Subjective Tests %X Cloud Gaming is a new kind of service, which combines the successful concepts of Cloud Computing and Online Gaming. It provides the entire game experience to the users remotely from a data center. The player is no longer dependent on a specific type or quality of gaming hardware, but is able to use common devices. The end device only needs a broadband internet connection and the ability to display High Definition (HD) video. While this may reduce hardware costs for users and increase the revenue for developers by leaving out the retail chain, it also raises new challenges for service quality in terms of bandwidth and latency for the underlying network. In this paper we present the results of a subjective user study we conducted into the user-perceived quality of experience (QoE) in Cloud Gaming. We design a measurement environment, that emulates this new type of service, define tests for users to assess the QoE, derive Key Influence Factors (KFI) and influences of content and perception from our results.
• Performance of Concurrent Multipath Transmissions - Measurements and Model Validation. Zinner, Thomas; Klein, Dominik; Tutschku, Kurt; Zseby, Tanja; Tran-Gia, Phuoc; Shavitt, Yuval. In Proceedings of the 7th Conference on Next Generation Internet Networks (NGI). Kaiserslautern, Germany, 2011.
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  Concurrent multipath transport layer mechanisms have gained recently increasing interest in research and standardization because of the potential for bandwidth aggregation, load balancing and increased reliability. Multihomed end devices may benefit from IP-based multipath protocols like Multipath TCP or Concurrent Multipath Transmission via SCTP. In the future, concurrent multipath transport might be transparent to network and transport layer protocols as proposed by the concept of Transport Virtualization. This mechanism enables the pooling of heterogeneous transmission technologies or physical paths. However, the selection and application of multiple paths and its impact on the transmission is non-intuitive. Our prior work on transport virtualization discussed the impact of delay diversity of pooled paths on concurrent data transmissions. A mathematical model was introduced enabling the analysis of packet re-ordering that occurs due to different path delays. In this paper we extend our investigations by validating the previously presented analytical and simulative models with measurements performed in Planetlab Europe and the Etomic testbed.

  @inproceedings{info3-inproceedings-2011-416, abstract = {Concurrent multipath transport layer mechanisms have gained recently increasing interest in research and standardization because of the potential for bandwidth aggregation, load balancing and increased reliability. Multihomed end devices may benefit from IP-based multipath protocols like Multipath TCP or Concurrent Multipath Transmission via SCTP. In the future, concurrent multipath transport might be transparent to network and transport layer protocols as proposed by the concept of Transport Virtualization. This mechanism enables the pooling of heterogeneous transmission technologies or physical paths. However, the selection and application of multiple paths and its impact on the transmission is non-intuitive. Our prior work on transport virtualization discussed the impact of delay diversity of pooled paths on concurrent data transmissions. A mathematical model was introduced enabling the analysis of packet re-ordering that occurs due to different path delays. In this paper we extend our investigations by validating the previously presented analytical and simulative models with measurements performed in Planetlab Europe and the Etomic testbed.}, address = {Kaiserslautern, Germany}, author = {Zinner, Thomas and Klein, Dominik and Tutschku, Kurt and Zseby, Tanja and Tran-Gia, Phuoc and Shavitt, Yuval}, booktitle = {Proceedings of the 7th Conference on Next Generation Internet Networks (NGI)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Performance of Concurrent Multipath Transmissions - Measurements and Model Validation}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-416 %A Zinner, Thomas %A Klein, Dominik %A Tutschku, Kurt %A Zseby, Tanja %A Tran-Gia, Phuoc %A Shavitt, Yuval %B Proceedings of the 7th Conference on Next Generation Internet Networks (NGI) %C Kaiserslautern, Germany %D 2011 %T Performance of Concurrent Multipath Transmissions - Measurements and Model Validation %X Concurrent multipath transport layer mechanisms have gained recently increasing interest in research and standardization because of the potential for bandwidth aggregation, load balancing and increased reliability. Multihomed end devices may benefit from IP-based multipath protocols like Multipath TCP or Concurrent Multipath Transmission via SCTP. In the future, concurrent multipath transport might be transparent to network and transport layer protocols as proposed by the concept of Transport Virtualization. This mechanism enables the pooling of heterogeneous transmission technologies or physical paths. However, the selection and application of multiple paths and its impact on the transmission is non-intuitive. Our prior work on transport virtualization discussed the impact of delay diversity of pooled paths on concurrent data transmissions. A mathematical model was introduced enabling the analysis of packet re-ordering that occurs due to different path delays. In this paper we extend our investigations by validating the previously presented analytical and simulative models with measurements performed in Planetlab Europe and the Etomic testbed.
• Influence of traffic management solutions on Quality of Experience for prevailing overlay applications. Stankiewicz, Rafal; Cholda, Piotr; Domzal, Jerzy; Wojcik, Robert; Hoßfeld, Tobias; Zinner, Thomas; Oechsner, Simon; Lehrieder, Frank. In Proceedings of the 7th Conference on Next Generation Internet Networks (NGI). Kaiserslautern, Germany, 2011.
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  Different sorts of peer-to-peer (P2P) applications emerge every day and they are becoming more and more popular. The performance of such applications may be measured by means of Quality of Experience (QoE) metrics. In this paper, we survey the factors that influence these metrics. Moreover, we assess the impact of traffic management solutions (e.g. proposed by ALTO or SmoothIT) on perceived QoE for the dominant overlay applications. The possible regulatory issues regarding QoE for P2P applications are also mentioned.

  @inproceedings{info3-inproceedings-2011-414, abstract = {Different sorts of peer-to-peer (P2P) applications emerge every day and they are becoming more and more popular. The performance of such applications may be measured by means of Quality of Experience (QoE) metrics. In this paper, we survey the factors that influence these metrics. Moreover, we assess the impact of traffic management solutions (e.g. proposed by ALTO or SmoothIT) on perceived QoE for the dominant overlay applications. The possible regulatory issues regarding QoE for P2P applications are also mentioned.}, address = {Kaiserslautern, Germany}, author = {Stankiewicz, Rafal and Cholda, Piotr and Domzal, Jerzy and Wojcik, Robert and Hoßfeld, Tobias and Zinner, Thomas and Oechsner, Simon and Lehrieder, Frank}, booktitle = {Proceedings of the 7th Conference on Next Generation Internet Networks (NGI)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Influence of traffic management solutions on Quality of Experience for prevailing overlay applications}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-414 %A Stankiewicz, Rafal %A Cholda, Piotr %A Domzal, Jerzy %A Wojcik, Robert %A Hoßfeld, Tobias %A Zinner, Thomas %A Oechsner, Simon %A Lehrieder, Frank %B Proceedings of the 7th Conference on Next Generation Internet Networks (NGI) %C Kaiserslautern, Germany %D 2011 %T Influence of traffic management solutions on Quality of Experience for prevailing overlay applications %X Different sorts of peer-to-peer (P2P) applications emerge every day and they are becoming more and more popular. The performance of such applications may be measured by means of Quality of Experience (QoE) metrics. In this paper, we survey the factors that influence these metrics. Moreover, we assess the impact of traffic management solutions (e.g. proposed by ALTO or SmoothIT) on perceived QoE for the dominant overlay applications. The possible regulatory issues regarding QoE for P2P applications are also mentioned.
• Cost-Optimal Validation Mechanisms and Cheat-Detection for Crowdsourcing Platforms. Hirth, Matthias; Hoßfeld, Tobias; Tran-Gia, Phuoc. In Workshop on Future Internet and Next Generation Networks (FINGNet). Seoul, Korea, 2011.
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  Crowdsourcing is becoming more and more important for commercial purposes. With the growth of crowdsourcing platforms like MTurk or Microworkers, a huge work force and a large knowledge base can be easily accessed and utilized. But due to the anonymity of the workers, they are encouraged to cheat the employers in order to maximize their income. Thus, this paper presents two crowd-based approaches to validate the submitted work. Both approaches are evaluated with regard to their detection quality, their costs and their applicability to different types of typical crowdsourcing tasks.

  @inproceedings{info3-inproceedings-2011-413, abstract = {Crowdsourcing is becoming more and more important for commercial purposes. With the growth of crowdsourcing platforms like MTurk or Microworkers, a huge work force and a large knowledge base can be easily accessed and utilized. But due to the anonymity of the workers, they are encouraged to cheat the employers in order to maximize their income. Thus, this paper presents two crowd-based approaches to validate the submitted work. Both approaches are evaluated with regard to their detection quality, their costs and their applicability to different types of typical crowdsourcing tasks.}, address = {Seoul, Korea}, author = {Hirth, Matthias and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {Workshop on Future Internet and Next Generation Networks (FINGNet)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Cost-Optimal Validation Mechanisms and Cheat-Detection for Crowdsourcing Platforms}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-413 %A Hirth, Matthias %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B Workshop on Future Internet and Next Generation Networks (FINGNet) %C Seoul, Korea %D 2011 %T Cost-Optimal Validation Mechanisms and Cheat-Detection for Crowdsourcing Platforms %X Crowdsourcing is becoming more and more important for commercial purposes. With the growth of crowdsourcing platforms like MTurk or Microworkers, a huge work force and a large knowledge base can be easily accessed and utilized. But due to the anonymity of the workers, they are encouraged to cheat the employers in order to maximize their income. Thus, this paper presents two crowd-based approaches to validate the submitted work. Both approaches are evaluated with regard to their detection quality, their costs and their applicability to different types of typical crowdsourcing tasks.
• Performance Comparison of Hardware Virtualization Platforms. Schlosser, Daniel; Duelli, Michael; Goll, Sebastian. In IFIP/TC6 NETWORKING 2011 (NETWORKING 2011). Valencia, Spain, 2011.
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  Hosting virtual servers on a shared physical hardware by means of hardware virtualization is common use at data centers, web hosters, and research facilities. All platforms include isolation techniques that restrict resource consumption of the virtual guest machines. However, these isolation techniques have an impact on the performance of the guest systems. In this paper, we study how popular hardware virtualization approaches (OpenVZ, KVM, Xen v4, VirtualBox, VMware ESXi) affect the network throughput of a virtualized system. We compare their impact in a dedicated and a shared host scenario as well as to the bare host system. Our results provide an overview on the performance of popular hardware virtualization platforms on commodity hardware in terms of network throughput.

  @inproceedings{info3-inproceedings-2011-407, abstract = {Hosting virtual servers on a shared physical hardware by means of hardware virtualization is common use at data centers, web hosters, and research facilities. All platforms include isolation techniques that restrict resource consumption of the virtual guest machines. However, these isolation techniques have an impact on the performance of the guest systems. In this paper, we study how popular hardware virtualization approaches (OpenVZ, KVM, Xen v4, VirtualBox, VMware ESXi) affect the network throughput of a virtualized system. We compare their impact in a dedicated and a shared host scenario as well as to the bare host system. Our results provide an overview on the performance of popular hardware virtualization platforms on commodity hardware in terms of network throughput.}, address = {Valencia, Spain}, author = {Schlosser, Daniel and Duelli, Michael and Goll, Sebastian}, booktitle = {IFIP/TC6 NETWORKING 2011 (NETWORKING 2011)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Performance Comparison of Hardware Virtualization Platforms}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-407 %A Schlosser, Daniel %A Duelli, Michael %A Goll, Sebastian %B IFIP/TC6 NETWORKING 2011 (NETWORKING 2011) %C Valencia, Spain %D 2011 %T Performance Comparison of Hardware Virtualization Platforms %X Hosting virtual servers on a shared physical hardware by means of hardware virtualization is common use at data centers, web hosters, and research facilities. All platforms include isolation techniques that restrict resource consumption of the virtual guest machines. However, these isolation techniques have an impact on the performance of the guest systems. In this paper, we study how popular hardware virtualization approaches (OpenVZ, KVM, Xen v4, VirtualBox, VMware ESXi) affect the network throughput of a virtualized system. We compare their impact in a dedicated and a shared host scenario as well as to the bare host system. Our results provide an overview on the performance of popular hardware virtualization platforms on commodity hardware in terms of network throughput.
• VNREAL: Virtual Network Resource Embedding ALgorithms in the Framework ALEVIN. Duelli, Michael; Schlosser, Daniel; Felipe Botero, Juan; Hesselbach, Xavier; Fischer, Andreas; de Meer, Hermann. In 7th Euro-NF Conference on Next Generation Internet Networks (NGI 2011). Kaiserslautern, Germany, 2011.
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  Network virtualization is recognized as an enabling technology for the Future Internet that overcomes network ossification. However, it introduces a set of challenges. In any network virtualization environment, the problem of optimally mapping virtual resources to physical resources, known as virtual network embedding (VNE), is a critical challenge. Several algorithms attempting to solve this problem have been proposed in literature, so far. However, comparison of existing and new VNE algorithms is hard, as each algorithm focuses on different criteria. To that end, the VNREAL project introduces ALEVIN, a framework to compare different algorithms according to a set of metrics, easily incorporate new VNE algorithms, and evaluate these algorithms on a given scenario for arbitrary parameters.

  @inproceedings{info3-inproceedings-2011-421, abstract = {Network virtualization is recognized as an enabling technology for the Future Internet that overcomes network ossification. However, it introduces a set of challenges. In any network virtualization environment, the problem of optimally mapping virtual resources to physical resources, known as virtual network embedding (VNE), is a critical challenge. Several algorithms attempting to solve this problem have been proposed in literature, so far. However, comparison of existing and new VNE algorithms is hard, as each algorithm focuses on different criteria. To that end, the VNREAL project introduces ALEVIN, a framework to compare different algorithms according to a set of metrics, easily incorporate new VNE algorithms, and evaluate these algorithms on a given scenario for arbitrary parameters.}, address = {Kaiserslautern, Germany}, author = {Duelli, Michael and Schlosser, Daniel and Felipe Botero, Juan and Hesselbach, Xavier and Fischer, Andreas and de Meer, Hermann}, booktitle = {7th Euro-NF Conference on Next Generation Internet Networks (NGI 2011)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {VNREAL: Virtual Network Resource Embedding ALgorithms in the Framework ALEVIN}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-421 %A Duelli, Michael %A Schlosser, Daniel %A Felipe Botero, Juan %A Hesselbach, Xavier %A Fischer, Andreas %A de Meer, Hermann %B 7th Euro-NF Conference on Next Generation Internet Networks (NGI 2011) %C Kaiserslautern, Germany %D 2011 %T VNREAL: Virtual Network Resource Embedding ALgorithms in the Framework ALEVIN %X Network virtualization is recognized as an enabling technology for the Future Internet that overcomes network ossification. However, it introduces a set of challenges. In any network virtualization environment, the problem of optimally mapping virtual resources to physical resources, known as virtual network embedding (VNE), is a critical challenge. Several algorithms attempting to solve this problem have been proposed in literature, so far. However, comparison of existing and new VNE algorithms is hard, as each algorithm focuses on different criteria. To that end, the VNREAL project introduces ALEVIN, a framework to compare different algorithms according to a set of metrics, easily incorporate new VNE algorithms, and evaluate these algorithms on a given scenario for arbitrary parameters.
• Cache Capacity Allocation to Overlay Swarms. Papafili, Ioanna; Stamoulis, George D.; Lehrieder, Frank; Kleine, Benjamin; Oechsner, Simon. In International Workshop on Self-Organizing Systems. Karlsruhe, Germany, 2011.
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  Peer-to-peer applications generate huge volumes of Internet traffic, thus leading to higher congestion, as well as higher costs for the ISPs particularly due to inter-domain traffic. The traditional traffic management approaches employed by ISPs (e.g. traffic shaping or even throttling) often lead to a deterioration of users‟ Quality-of-Experience. Previous works have verified that the insertion of ISP-owned Peers (IoPs) can deal effectively with this situation. The mechanism offers caching while exploiting the self-organizing structure of overlays. Thus, it leads to both improved performance for peers and reduced inter-domain traffic costs for ISPs. In this paper, we study how the available IoP bandwidth capacity should be allocated among the various swarms that it can possibly join. In particular, we identify a variety of factors that influence the effectiveness of Swarm Selection and Bandwidth Allocation, and we investigate their impact on the practically relevant example of BitTorrent, primarily by means of simulations.

  @inproceedings{info3-inproceedings-2011-402, abstract = {Peer-to-peer applications generate huge volumes of Internet traffic, thus leading to higher congestion, as well as higher costs for the ISPs particularly due to inter-domain traffic. The traditional traffic management approaches employed by ISPs (e.g. traffic shaping or even throttling) often lead to a deterioration of users‟ Quality-of-Experience. Previous works have verified that the insertion of ISP-owned Peers (IoPs) can deal effectively with this situation. The mechanism offers caching while exploiting the self-organizing structure of overlays. Thus, it leads to both improved performance for peers and reduced inter-domain traffic costs for ISPs. In this paper, we study how the available IoP bandwidth capacity should be allocated among the various swarms that it can possibly join. In particular, we identify a variety of factors that influence the effectiveness of Swarm Selection and Bandwidth Allocation, and we investigate their impact on the practically relevant example of BitTorrent, primarily by means of simulations.}, address = {Karlsruhe, Germany}, author = {Papafili, Ioanna and Stamoulis, George D. and Lehrieder, Frank and Kleine, Benjamin and Oechsner, Simon}, booktitle = {International Workshop on Self-Organizing Systems}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {Cache Capacity Allocation to Overlay Swarms}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-402 %A Papafili, Ioanna %A Stamoulis, George D. %A Lehrieder, Frank %A Kleine, Benjamin %A Oechsner, Simon %B International Workshop on Self-Organizing Systems %C Karlsruhe, Germany %D 2011 %T Cache Capacity Allocation to Overlay Swarms %X Peer-to-peer applications generate huge volumes of Internet traffic, thus leading to higher congestion, as well as higher costs for the ISPs particularly due to inter-domain traffic. The traditional traffic management approaches employed by ISPs (e.g. traffic shaping or even throttling) often lead to a deterioration of users‟ Quality-of-Experience. Previous works have verified that the insertion of ISP-owned Peers (IoPs) can deal effectively with this situation. The mechanism offers caching while exploiting the self-organizing structure of overlays. Thus, it leads to both improved performance for peers and reduced inter-domain traffic costs for ISPs. In this paper, we study how the available IoP bandwidth capacity should be allocated among the various swarms that it can possibly join. In particular, we identify a variety of factors that influence the effectiveness of Swarm Selection and Bandwidth Allocation, and we investigate their impact on the practically relevant example of BitTorrent, primarily by means of simulations.
• A Subscription Model for Time-Scheduled Data Transfers. Klein, Dominik; Menth, Michael; Pries, Rastin; Tran-Gia, Phuoc; Scharf, Michael; Söllner, Michael. In 12th IFIP/IEEE International Symposium on Integrated Network Management (IM 2011). Dublin, Ireland, 2011.
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  We recently witness new services that can afford some delay until data transmission starts, but then benefit from a very large available bandwidth. A popular example is the migration of virtual machines between different sites of a geographically dispersed service provider. In this paper, we propose a subscription model for time-scheduled data transfers. Transmission requests are served consecutively, giving the flows access to the physical bandwidth. This is in contrast to today's Internet where flows are served in parallel so that they compete for the available bandwidth. We present the architecture to enable such data beams. Furthermore, we model and analyze the performance under different conditions and compare it with concurrent transmission.

  @inproceedings{info3-inproceedings-2011-400, abstract = {We recently witness new services that can afford some delay until data transmission starts, but then benefit from a very large available bandwidth. A popular example is the migration of virtual machines between different sites of a geographically dispersed service provider. In this paper, we propose a subscription model for time-scheduled data transfers. Transmission requests are served consecutively, giving the flows access to the physical bandwidth. This is in contrast to today's Internet where flows are served in parallel so that they compete for the available bandwidth. We present the architecture to enable such data beams. Furthermore, we model and analyze the performance under different conditions and compare it with concurrent transmission.}, address = {Dublin, Ireland}, author = {Klein, Dominik and Menth, Michael and Pries, Rastin and Tran-Gia, Phuoc and Scharf, Michael and Söllner, Michael}, booktitle = {12th IFIP/IEEE International Symposium on Integrated Network Management (IM 2011)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {A Subscription Model for Time-Scheduled Data Transfers}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-400 %A Klein, Dominik %A Menth, Michael %A Pries, Rastin %A Tran-Gia, Phuoc %A Scharf, Michael %A Söllner, Michael %B 12th IFIP/IEEE International Symposium on Integrated Network Management (IM 2011) %C Dublin, Ireland %D 2011 %T A Subscription Model for Time-Scheduled Data Transfers %X We recently witness new services that can afford some delay until data transmission starts, but then benefit from a very large available bandwidth. A popular example is the migration of virtual machines between different sites of a geographically dispersed service provider. In this paper, we propose a subscription model for time-scheduled data transfers. Transmission requests are served consecutively, giving the flows access to the physical bandwidth. This is in contrast to today's Internet where flows are served in parallel so that they compete for the available bandwidth. We present the architecture to enable such data beams. Furthermore, we model and analyze the performance under different conditions and compare it with concurrent transmission.
• ToMaTo - a network experimentation tool. Schwerdel, Dennis; Hock, David; Günther, Daniel; Reuther, Bernd; Müller, Paul; Tran-Gia, Phuoc. In 7th International ICST Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities (TridentCom 2011). Shanghai, China, 2011.
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  @inproceedings{info3-inproceedings-2011-409, address = {Shanghai, China}, author = {Schwerdel, Dennis and Hock, David and Günther, Daniel and Reuther, Bernd and Müller, Paul and Tran-Gia, Phuoc}, booktitle = {7th International ICST Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities (TridentCom 2011)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {ToMaTo - a network experimentation tool}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-409 %A Schwerdel, Dennis %A Hock, David %A Günther, Daniel %A Reuther, Bernd %A Müller, Paul %A Tran-Gia, Phuoc %B 7th International ICST Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities (TridentCom 2011) %C Shanghai, China %D 2011 %T ToMaTo - a network experimentation tool
• On the Impact of Quality Adaptation in SVC-based P2P Video-on-Demand Systems. Abboud, Osama; Zinner, Thomas; Pussep, Konstantin; Steinmetz, Ralf. In ACM Multimedia Systems. San Jose, California, 2011.
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  P2P Video-on-Demand (VoD) based on Scalable Video Coding (SVC) (the scalable extension of the H.264/AVC standard) is gaining momentum in the research community, as it provides elegant adaptation to heterogeneous resources and network dynamics. The major question is, how do the adaptation algorithms and designs affect the overall perceived performance of the system? Better yet, how can the performance of an SVC-based VoD system be defined? This paper explores the impact and trade-offs of SVC-based quality adaptation with focus on the SVC layer selection algorithms, which are performed at different streaming stages. We carry out extensive experiments to evaluate the performance in terms of session quality (start-up delay, video stalls) and delivered SVC video quality (layer switches, received layers), and find out that these two metrics exhibit a trade-off. Our analysis and conclusions give multimedia providers insights on how to design and fine-tune their VoD system in order to achieve best performance.

  @inproceedings{info3-inproceedings-2011-401, abstract = {P2P Video-on-Demand (VoD) based on Scalable Video Coding (SVC) (the scalable extension of the H.264/AVC standard) is gaining momentum in the research community, as it provides elegant adaptation to heterogeneous resources and network dynamics. The major question is, how do the adaptation algorithms and designs affect the overall perceived performance of the system? Better yet, how can the performance of an SVC-based VoD system be defined? This paper explores the impact and trade-offs of SVC-based quality adaptation with focus on the SVC layer selection algorithms, which are performed at different streaming stages. We carry out extensive experiments to evaluate the performance in terms of session quality (start-up delay, video stalls) and delivered SVC video quality (layer switches, received layers), and find out that these two metrics exhibit a trade-off. Our analysis and conclusions give multimedia providers insights on how to design and fine-tune their VoD system in order to achieve best performance.}, address = {San Jose, California}, author = {Abboud, Osama and Zinner, Thomas and Pussep, Konstantin and Steinmetz, Ralf}, booktitle = {ACM Multimedia Systems}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {On the Impact of Quality Adaptation in SVC-based P2P Video-on-Demand Systems}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-401 %A Abboud, Osama %A Zinner, Thomas %A Pussep, Konstantin %A Steinmetz, Ralf %B ACM Multimedia Systems %C San Jose, California %D 2011 %T On the Impact of Quality Adaptation in SVC-based P2P Video-on-Demand Systems %X P2P Video-on-Demand (VoD) based on Scalable Video Coding (SVC) (the scalable extension of the H.264/AVC standard) is gaining momentum in the research community, as it provides elegant adaptation to heterogeneous resources and network dynamics. The major question is, how do the adaptation algorithms and designs affect the overall perceived performance of the system? Better yet, how can the performance of an SVC-based VoD system be defined? This paper explores the impact and trade-offs of SVC-based quality adaptation with focus on the SVC layer selection algorithms, which are performed at different streaming stages. We carry out extensive experiments to evaluate the performance in terms of session quality (start-up delay, video stalls) and delivered SVC video quality (layer switches, received layers), and find out that these two metrics exhibit a trade-off. Our analysis and conclusions give multimedia providers insights on how to design and fine-tune their VoD system in order to achieve best performance.
• Aquarema in Action: Improving the YouTube QoE in Wireless Mesh Networks. Staehle, Barbara; Hirth, Matthias; Pries, Rastin; Wamser, Florian; Staehle, Dirk. In Baltic Congress on Future Internet Communications (BCFIC). Riga, Latvia, 2011.
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  Internet access networks in general and wireless mesh access networks in particular, are the bottleneck of today’s communication networks and consequently most strongly responsible for determining the user satisfaction. The limited bandwidth and the fact that access network are most often used as mere bit pipes are however unfavorable for the users’ quality of experience (QoE). The lack of application-specific service guarantees is especially inadequate in the face of an increasing degree of heterogeneity of Internet applications and their individual service requirements. Application and quality of experience resource management, Aquarema for short, addresses this challenge by enabling application specific network resource management and thereby improves the user QoE. This is achieved by the interaction of application comfort (AC) monitoring tools, running at the clients, and a network advisor which may trigger different resource management tools. AC quantifies how well an application is running and in particular, enables a prediction of the user experience, thereby allowing the network advisor to act upon an imminent QoE degradation. We demonstrate the appeal of Aquarema at the example of YouTube video streaming in a congested IEEE 802.11 based mesh testbed where AC-aware traffic shaping guarantees the successful video playback.

  @inproceedings{info3-inproceedings-2011-403, abstract = {Internet access networks in general and wireless mesh access networks in particular, are the bottleneck of today’s communication networks and consequently most strongly responsible for determining the user satisfaction. The limited bandwidth and the fact that access network are most often used as mere bit pipes are however unfavorable for the users’ quality of experience (QoE). The lack of application-specific service guarantees is especially inadequate in the face of an increasing degree of heterogeneity of Internet applications and their individual service requirements. Application and quality of experience resource management, Aquarema for short, addresses this challenge by enabling application specific network resource management and thereby improves the user QoE. This is achieved by the interaction of application comfort (AC) monitoring tools, running at the clients, and a network advisor which may trigger different resource management tools. AC quantifies how well an application is running and in particular, enables a prediction of the user experience, thereby allowing the network advisor to act upon an imminent QoE degradation. We demonstrate the appeal of Aquarema at the example of YouTube video streaming in a congested IEEE 802.11 based mesh testbed where AC-aware traffic shaping guarantees the successful video playback.}, address = {Riga, Latvia}, author = {Staehle, Barbara and Hirth, Matthias and Pries, Rastin and Wamser, Florian and Staehle, Dirk}, booktitle = {Baltic Congress on Future Internet Communications (BCFIC)}, keywords = {demobenefit}, month = {02}, title = {Aquarema in Action: Improving the YouTube QoE in Wireless Mesh Networks}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-403 %A Staehle, Barbara %A Hirth, Matthias %A Pries, Rastin %A Wamser, Florian %A Staehle, Dirk %B Baltic Congress on Future Internet Communications (BCFIC) %C Riga, Latvia %D 2011 %T Aquarema in Action: Improving the YouTube QoE in Wireless Mesh Networks %X Internet access networks in general and wireless mesh access networks in particular, are the bottleneck of today’s communication networks and consequently most strongly responsible for determining the user satisfaction. The limited bandwidth and the fact that access network are most often used as mere bit pipes are however unfavorable for the users’ quality of experience (QoE). The lack of application-specific service guarantees is especially inadequate in the face of an increasing degree of heterogeneity of Internet applications and their individual service requirements. Application and quality of experience resource management, Aquarema for short, addresses this challenge by enabling application specific network resource management and thereby improves the user QoE. This is achieved by the interaction of application comfort (AC) monitoring tools, running at the clients, and a network advisor which may trigger different resource management tools. AC quantifies how well an application is running and in particular, enables a prediction of the user experience, thereby allowing the network advisor to act upon an imminent QoE degradation. We demonstrate the appeal of Aquarema at the example of YouTube video streaming in a congested IEEE 802.11 based mesh testbed where AC-aware traffic shaping guarantees the successful video playback.
• Compact node-link formulations for the optimal single path MPLS Fast Reroute layout. Żukowski, Cezary; Tomaszewski, Artur; Pióro, Michał; Hock, David; Hartmann, Matthias; Menth, Michael. In 1st European Teletraffic Seminar (ETS). Poznan, Poland, 2011.
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  @inproceedings{info3-inproceedings-2011-408, address = {Poznan, Poland}, author = {Żukowski, Cezary and Tomaszewski, Artur and Pióro, Michał and Hock, David and Hartmann, Matthias and Menth, Michael}, booktitle = {1st European Teletraffic Seminar (ETS)}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {Compact node-link formulations for the optimal single path MPLS Fast Reroute layout}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-408 %A Żukowski, Cezary %A Tomaszewski, Artur %A Pióro, Michał %A Hock, David %A Hartmann, Matthias %A Menth, Michael %B 1st European Teletraffic Seminar (ETS) %C Poznan, Poland %D 2011 %T Compact node-link formulations for the optimal single path MPLS Fast Reroute layout
• Anatomy of a Crowdsourcing Platform - Using the Example of Microworkers.com. Hirth, Matthias; Hoßfeld, Tobias; Tran-Gia, Phuoc. In Workshop on Future Internet and Next Generation Networks (FINGNet). Seoul, Korea, 2011.
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  Since Jeff Howe introduced the term “crowdsourcing” in 2006 for the first time, crowdsourcing has be come a growing market in the current Internet. Thousands of workers categorize images, write articles or perform other small tasks on platforms like Amazon Mechanical Turk (MTurk), Microworkers or ShortTask. In this work, we want to give an inside view of the usage data from Microworkers and show that there are significant differences to the well studied MTurk. Further, we have a look at Microworkers from the perspective for a worker, an employer and the platform owner, in order to answer their most important questions: What jobs are most paid? How do I get my work done most quickly? When are the users of my platform active?

  @inproceedings{info3-inproceedings-2011-410, abstract = {Since Jeff Howe introduced the term “crowdsourcing” in 2006 for the first time, crowdsourcing has be come a growing market in the current Internet. Thousands of workers categorize images, write articles or perform other small tasks on platforms like Amazon Mechanical Turk (MTurk), Microworkers or ShortTask. In this work, we want to give an inside view of the usage data from Microworkers and show that there are significant differences to the well studied MTurk. Further, we have a look at Microworkers from the perspective for a worker, an employer and the platform owner, in order to answer their most important questions: What jobs are most paid? How do I get my work done most quickly? When are the users of my platform active?}, address = {Seoul, Korea}, author = {Hirth, Matthias and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {Workshop on Future Internet and Next Generation Networks (FINGNet)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Anatomy of a Crowdsourcing Platform - Using the Example of Microworkers.com}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-410 %A Hirth, Matthias %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B Workshop on Future Internet and Next Generation Networks (FINGNet) %C Seoul, Korea %D 2011 %T Anatomy of a Crowdsourcing Platform - Using the Example of Microworkers.com %X Since Jeff Howe introduced the term “crowdsourcing” in 2006 for the first time, crowdsourcing has be come a growing market in the current Internet. Thousands of workers categorize images, write articles or perform other small tasks on platforms like Amazon Mechanical Turk (MTurk), Microworkers or ShortTask. In this work, we want to give an inside view of the usage data from Microworkers and show that there are significant differences to the well studied MTurk. Further, we have a look at Microworkers from the perspective for a worker, an employer and the platform owner, in order to answer their most important questions: What jobs are most paid? How do I get my work done most quickly? When are the users of my platform active?
• FoG and Clouds: Optimizing QoE for YouTube. Hoßfeld, Tobias; Liers, Florian; Volkert, Thomas; Schatz, Raimund. In KuVS 5thGI/ITG KuVS Fachgespräch NG Service Delivery Platforms. Munich, Germany, 2011.
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  This work focuses on optimizing QoE for YouTube video streaming. We consider a bottleneck scenario, in which the available network data rate is limited to B. When downloading a video which is encoded with a certain video bit rate V<B, stalling may occur. However, stalling may also occur if the network data rate is sufficient on average to download the video during the playout time because of the variable video bit rate. To compensate such effects, a video player typically implements a video buffer. Thus, if the video is buffered long enough, no stalling will occur. From the end user’s point of view, it is more convenient to experience no stalling at all during the playout even at the cost of an increased initial delay, than having small initial delays but also stalling. The question arises how to set up the initial delay such that stalling occurs with low probability. In Section II, we model the impact of variable bit rate encoding on stalling. Then, we derive an approximation for the initial delay, such that stalling will likely not occur. Next, we discuss in Section III the interaction between application and network stack. In particular, we discuss how to exchange required information using the GAPI interface and propose the FoG (“Forwarding on Gates”) stack as possible implementation solution which is currently work in progress.

  @inproceedings{info3-inproceedings-2011-428, abstract = {This work focuses on optimizing QoE for YouTube video streaming. We consider a bottleneck scenario, in which the available network data rate is limited to B. When downloading a video which is encoded with a certain video bit rate V<B, stalling may occur. However, stalling may also occur if the network data rate is sufficient on average to download the video during the playout time because of the variable video bit rate. To compensate such effects, a video player typically implements a video buffer. Thus, if the video is buffered long enough, no stalling will occur. From the end user’s point of view, it is more convenient to experience no stalling at all during the playout even at the cost of an increased initial delay, than having small initial delays but also stalling. The question arises how to set up the initial delay such that stalling occurs with low probability. In Section II, we model the impact of variable bit rate encoding on stalling. Then, we derive an approximation for the initial delay, such that stalling will likely not occur. Next, we discuss in Section III the interaction between application and network stack. In particular, we discuss how to exchange required information using the GAPI interface and propose the FoG (“Forwarding on Gates”) stack as possible implementation solution which is currently work in progress.}, address = {Munich, Germany}, author = {Hoßfeld, Tobias and Liers, Florian and Volkert, Thomas and Schatz, Raimund}, booktitle = {KuVS 5thGI/ITG KuVS Fachgespräch NG Service Delivery Platforms}, keywords = {demobenefit}, month = 10, title = {FoG and Clouds: Optimizing QoE for YouTube}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-428 %A Hoßfeld, Tobias %A Liers, Florian %A Volkert, Thomas %A Schatz, Raimund %B KuVS 5thGI/ITG KuVS Fachgespräch NG Service Delivery Platforms %C Munich, Germany %D 2011 %T FoG and Clouds: Optimizing QoE for YouTube %X This work focuses on optimizing QoE for YouTube video streaming. We consider a bottleneck scenario, in which the available network data rate is limited to B. When downloading a video which is encoded with a certain video bit rate V<B, stalling may occur. However, stalling may also occur if the network data rate is sufficient on average to download the video during the playout time because of the variable video bit rate. To compensate such effects, a video player typically implements a video buffer. Thus, if the video is buffered long enough, no stalling will occur. From the end user’s point of view, it is more convenient to experience no stalling at all during the playout even at the cost of an increased initial delay, than having small initial delays but also stalling. The question arises how to set up the initial delay such that stalling occurs with low probability. In Section II, we model the impact of variable bit rate encoding on stalling. Then, we derive an approximation for the initial delay, such that stalling will likely not occur. Next, we discuss in Section III the interaction between application and network stack. In particular, we discuss how to exchange required information using the GAPI interface and propose the FoG (“Forwarding on Gates”) stack as possible implementation solution which is currently work in progress.
• MultiNext - Measuring Concurrent Multipath Transmissions in an Experimental Facility. Zinner, Thomas; Tutschku, Kurt; Zseby, Tanja. In Proceedings of the 7th Conference on Next Generation Internet Networks (NGI). Kaiserslautern, Germany, 2011.
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  @inproceedings{info3-inproceedings-2011-419, address = {Kaiserslautern, Germany}, author = {Zinner, Thomas and Tutschku, Kurt and Zseby, Tanja}, booktitle = {Proceedings of the 7th Conference on Next Generation Internet Networks (NGI)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {MultiNext - Measuring Concurrent Multipath Transmissions in an Experimental Facility}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-419 %A Zinner, Thomas %A Tutschku, Kurt %A Zseby, Tanja %B Proceedings of the 7th Conference on Next Generation Internet Networks (NGI) %C Kaiserslautern, Germany %D 2011 %T MultiNext - Measuring Concurrent Multipath Transmissions in an Experimental Facility
• Modeling and Performance Evaluation of an OpenFlow Architecture. Jarschel, Michael; Oechsner, Simon; Schlosser, Daniel; Pries, Rastin; Goll, Sebastian; Tran-Gia, Phuoc. In 23rd International Teletraffic Congress (ITC 2011). San Francisco, CA, USA, 2011.
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  The OpenFlow concept of flow-based forwarding and separation of the control plane from the data plane provides a new flexibility in network innovation. While initially used solely in the research domain, OpenFlow is now finding its way into commercial applications. However, this creates new challenges, as questions of OpenFlow scalability and performance have not yet been answered. This paper is a first step towards that goal. Based on measurements of switching times of current OpenFlow hardware, we derive a basic model for the forwarding speed and blocking probability of an OpenFlow switch combined with an OpenFlow controller and validate it using a simulation. This model can be used to estimate the packet sojourn time and the probability of lost packets in such a system and can give hints to developers and researchers on questions how an OpenFlow architecture will perform given certain parameters.

  @inproceedings{info3-inproceedings-2011-423, abstract = {The OpenFlow concept of flow-based forwarding and separation of the control plane from the data plane provides a new flexibility in network innovation. While initially used solely in the research domain, OpenFlow is now finding its way into commercial applications. However, this creates new challenges, as questions of OpenFlow scalability and performance have not yet been answered. This paper is a first step towards that goal. Based on measurements of switching times of current OpenFlow hardware, we derive a basic model for the forwarding speed and blocking probability of an OpenFlow switch combined with an OpenFlow controller and validate it using a simulation. This model can be used to estimate the packet sojourn time and the probability of lost packets in such a system and can give hints to developers and researchers on questions how an OpenFlow architecture will perform given certain parameters.}, address = {San Francisco, CA, USA}, author = {Jarschel, Michael and Oechsner, Simon and Schlosser, Daniel and Pries, Rastin and Goll, Sebastian and Tran-Gia, Phuoc}, booktitle = {23rd International Teletraffic Congress (ITC 2011)}, keywords = {openflow}, month = {09}, title = {Modeling and Performance Evaluation of an OpenFlow Architecture}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-423 %A Jarschel, Michael %A Oechsner, Simon %A Schlosser, Daniel %A Pries, Rastin %A Goll, Sebastian %A Tran-Gia, Phuoc %B 23rd International Teletraffic Congress (ITC 2011) %C San Francisco, CA, USA %D 2011 %T Modeling and Performance Evaluation of an OpenFlow Architecture %X The OpenFlow concept of flow-based forwarding and separation of the control plane from the data plane provides a new flexibility in network innovation. While initially used solely in the research domain, OpenFlow is now finding its way into commercial applications. However, this creates new challenges, as questions of OpenFlow scalability and performance have not yet been answered. This paper is a first step towards that goal. Based on measurements of switching times of current OpenFlow hardware, we derive a basic model for the forwarding speed and blocking probability of an OpenFlow switch combined with an OpenFlow controller and validate it using a simulation. This model can be used to estimate the packet sojourn time and the probability of lost packets in such a system and can give hints to developers and researchers on questions how an OpenFlow architecture will perform given certain parameters.
• The QoE Provisioning-Delivery-Hysteresis and Its Importance for Service Provisioning in the Future Internet. Hoßfeld, Tobias; Fiedler, Markus; Zinner, Thomas. In Proceedings of the 7th Conference on Next Generation Internet Networks (NGI). Kaiserslautern, Germany, 2011.
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  Quality of Experience (QoE) combines non-technical parameters such as user perception, experience and expectations with technical parameters such as application- and network-level Quality of Service (QoS). For service or network providers, it is important to understand the quantitative relationship between QoE and these technical parameters in order to manage the user perceived quality. This paper investigates the different impacts of a) provisioning and b) delivery problems due to insufficient resources on QoE, leading to the QoE provisioning-delivery hysteresis (QoE-PDH). We demonstrate the QoE-PDH for Voice-over-IP, live video streaming, and web browsing based on existing measurement studies. The results clearly quantify the necessity to control quality, instead of suffering from uncontrollable impacts like packet loss caused by congestion. The implementation and the limitations of the QoE-PDH in the current Internet is shown using the example of Skype. Afterwards we discuss how these results can be used th enhance service provisioning and delivery in the Future Internet.

  @inproceedings{info3-inproceedings-2011-415, abstract = {Quality of Experience (QoE) combines non-technical parameters such as user perception, experience and expectations with technical parameters such as application- and network-level Quality of Service (QoS). For service or network providers, it is important to understand the quantitative relationship between QoE and these technical parameters in order to manage the user perceived quality. This paper investigates the different impacts of a) provisioning and b) delivery problems due to insufficient resources on QoE, leading to the QoE provisioning-delivery hysteresis (QoE-PDH). We demonstrate the QoE-PDH for Voice-over-IP, live video streaming, and web browsing based on existing measurement studies. The results clearly quantify the necessity to control quality, instead of suffering from uncontrollable impacts like packet loss caused by congestion. The implementation and the limitations of the QoE-PDH in the current Internet is shown using the example of Skype. Afterwards we discuss how these results can be used th enhance service provisioning and delivery in the Future Internet.}, address = {Kaiserslautern, Germany}, author = {Hoßfeld, Tobias and Fiedler, Markus and Zinner, Thomas}, booktitle = {Proceedings of the 7th Conference on Next Generation Internet Networks (NGI)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {The QoE Provisioning-Delivery-Hysteresis and Its Importance for Service Provisioning in the Future Internet}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-415 %A Hoßfeld, Tobias %A Fiedler, Markus %A Zinner, Thomas %B Proceedings of the 7th Conference on Next Generation Internet Networks (NGI) %C Kaiserslautern, Germany %D 2011 %T The QoE Provisioning-Delivery-Hysteresis and Its Importance for Service Provisioning in the Future Internet %X Quality of Experience (QoE) combines non-technical parameters such as user perception, experience and expectations with technical parameters such as application- and network-level Quality of Service (QoS). For service or network providers, it is important to understand the quantitative relationship between QoE and these technical parameters in order to manage the user perceived quality. This paper investigates the different impacts of a) provisioning and b) delivery problems due to insufficient resources on QoE, leading to the QoE provisioning-delivery hysteresis (QoE-PDH). We demonstrate the QoE-PDH for Voice-over-IP, live video streaming, and web browsing based on existing measurement studies. The results clearly quantify the necessity to control quality, instead of suffering from uncontrollable impacts like packet loss caused by congestion. The implementation and the limitations of the QoE-PDH in the current Internet is shown using the example of Skype. Afterwards we discuss how these results can be used th enhance service provisioning and delivery in the Future Internet.
• Quantification of YouTube QoE via Crowdsourcing. Hoßfeld, Tobias; Schatz, Raimund; Seufert, Michael; Hirth, Matthias; Zinner, Thomas; Tran-Gia, Phuoc. In IEEE International Workshop on Multimedia Quality of Experience - Modeling, Evaluation, and Directions (MQoE). Dana Point, CA, USA, 2011.
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  This paper addresses the challenge of assessing and modeling Quality of Experience (QoE) for online video services that are based on TCP-streaming. We present a dedicated QoE model for YouTube that takes into account the key influence factors (such as stalling events caused by network bottlenecks) that shape quality perception of this service. As second contribution, we propose a generic subjective QoE assessment methodology for multimedia applications (like online video) that is based on crowdsourcing - a highly cost-efficient, fast and flexible way of conducting user experiments. We demonstrate how our approach successfully leverages the inherent strengths of crowdsourcing while addressing critical aspects such as the reliability of the experimental data obtained. Our results suggest that, crowdsourcing is a highly effective QoE assessment method not only for online video, but also for a wide range of other current and future Internet applications.

  @inproceedings{info3-inproceedings-2011-426, abstract = {This paper addresses the challenge of assessing and modeling Quality of Experience (QoE) for online video services that are based on TCP-streaming. We present a dedicated QoE model for YouTube that takes into account the key influence factors (such as stalling events caused by network bottlenecks) that shape quality perception of this service. As second contribution, we propose a generic subjective QoE assessment methodology for multimedia applications (like online video) that is based on crowdsourcing - a highly cost-efficient, fast and flexible way of conducting user experiments. We demonstrate how our approach successfully leverages the inherent strengths of crowdsourcing while addressing critical aspects such as the reliability of the experimental data obtained. Our results suggest that, crowdsourcing is a highly effective QoE assessment method not only for online video, but also for a wide range of other current and future Internet applications.}, address = {Dana Point, CA, USA}, author = {Hoßfeld, Tobias and Schatz, Raimund and Seufert, Michael and Hirth, Matthias and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {IEEE International Workshop on Multimedia Quality of Experience - Modeling, Evaluation, and Directions (MQoE)}, keywords = {demobenefit}, month = 12, title = {Quantification of YouTube QoE via Crowdsourcing}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-426 %A Hoßfeld, Tobias %A Schatz, Raimund %A Seufert, Michael %A Hirth, Matthias %A Zinner, Thomas %A Tran-Gia, Phuoc %B IEEE International Workshop on Multimedia Quality of Experience - Modeling, Evaluation, and Directions (MQoE) %C Dana Point, CA, USA %D 2011 %T Quantification of YouTube QoE via Crowdsourcing %X This paper addresses the challenge of assessing and modeling Quality of Experience (QoE) for online video services that are based on TCP-streaming. We present a dedicated QoE model for YouTube that takes into account the key influence factors (such as stalling events caused by network bottlenecks) that shape quality perception of this service. As second contribution, we propose a generic subjective QoE assessment methodology for multimedia applications (like online video) that is based on crowdsourcing - a highly cost-efficient, fast and flexible way of conducting user experiments. We demonstrate how our approach successfully leverages the inherent strengths of crowdsourcing while addressing critical aspects such as the reliability of the experimental data obtained. Our results suggest that, crowdsourcing is a highly effective QoE assessment method not only for online video, but also for a wide range of other current and future Internet applications.
• Power Consumption Analysis of Data Center Architectures. Pries, Rastin; Jarschel, Michael; Schlosser, Daniel; Klopf, Michael; Tran-Gia, Phuoc. In GreenNets. Colmar, France, 2011.
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  The high power consumption of data centers confronts the providers with major challenges. However, not only the servers and the cooling consume a huge amount of energy, but also the data center network architecture makes an important contribution. In this paper, we introduce different data center architectures and compare them regarding their power consumption. The results show that there are some differences which should not be neglected and that with only minor modifications of the architecture, it is possible to save a huge amount of energy.

  @inproceedings{info3-inproceedings-2011-424, abstract = {The high power consumption of data centers confronts the providers with major challenges. However, not only the servers and the cooling consume a huge amount of energy, but also the data center network architecture makes an important contribution. In this paper, we introduce different data center architectures and compare them regarding their power consumption. The results show that there are some differences which should not be neglected and that with only minor modifications of the architecture, it is possible to save a huge amount of energy.}, address = {Colmar, France}, author = {Pries, Rastin and Jarschel, Michael and Schlosser, Daniel and Klopf, Michael and Tran-Gia, Phuoc}, booktitle = {GreenNets}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Power Consumption Analysis of Data Center Architectures}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-424 %A Pries, Rastin %A Jarschel, Michael %A Schlosser, Daniel %A Klopf, Michael %A Tran-Gia, Phuoc %B GreenNets %C Colmar, France %D 2011 %T Power Consumption Analysis of Data Center Architectures %X The high power consumption of data centers confronts the providers with major challenges. However, not only the servers and the cooling consume a huge amount of energy, but also the data center network architecture makes an important contribution. In this paper, we introduce different data center architectures and compare them regarding their power consumption. The results show that there are some differences which should not be neglected and that with only minor modifications of the architecture, it is possible to save a huge amount of energy.
• Exploring YouTube’s content distribution network through distributed application-layer measurements: a first view. Rafetseder, Albert; Metzger, Florian; Stezenbach, David; Tutschku, Kurt. In Proceedings of the 2011 International Workshop on Modeling, Analysis, and Control of Complex Networks (Cnet ’11). 2011.
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  @inproceedings{info3-inproceedings-2011-27, author = {Rafetseder, Albert and Metzger, Florian and Stezenbach, David and Tutschku, Kurt}, booktitle = {Proceedings of the 2011 International Workshop on Modeling, Analysis, and Control of Complex Networks (Cnet '11)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Exploring YouTube's content distribution network through distributed application-layer measurements: a first view}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-27 %A Rafetseder, Albert %A Metzger, Florian %A Stezenbach, David %A Tutschku, Kurt %B Proceedings of the 2011 International Workshop on Modeling, Analysis, and Control of Complex Networks (Cnet '11) %D 2011 %T Exploring YouTube's content distribution network through distributed application-layer measurements: a first view
• SOS: The MOS is not enough!. Hoßfeld, Tobias; Schatz, Raimund; Egger, Sebastian. In QoMEX 2011. Mechelen, Belgium, 2011.
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  When it comes to analysis and interpretation of the results of subjective QoE studies, one often witnesses a lack of attention to the diversity in subjective user ratings. In extreme cases, solely Mean Opinion Scores (MOS) are reported, causing the loss of important information on the user rating diversity. In this paper, we emphasize the importance of considering the Standard deviation of Opinion Scores (SOS) and analyze important characteristics of this measure. As a result, we formulate the SOS hypothesis which postulates a square relationship between the MOS and the SOS. We demonstrate the validity and applicability of the SOS hypothesis for a wide range of studies. The main benefit of the SOS hypothesis is that it allows for a compact, yet still comprehensive statistical summary of subjective user tests. Furthermore, it supports checking the reliability of test result data sets as well as their comparability across different QoE studies.

  @inproceedings{info3-inproceedings-2011-422, abstract = {When it comes to analysis and interpretation of the results of subjective QoE studies, one often witnesses a lack of attention to the diversity in subjective user ratings. In extreme cases, solely Mean Opinion Scores (MOS) are reported, causing the loss of important information on the user rating diversity. In this paper, we emphasize the importance of considering the Standard deviation of Opinion Scores (SOS) and analyze important characteristics of this measure. As a result, we formulate the SOS hypothesis which postulates a square relationship between the MOS and the SOS. We demonstrate the validity and applicability of the SOS hypothesis for a wide range of studies. The main benefit of the SOS hypothesis is that it allows for a compact, yet still comprehensive statistical summary of subjective user tests. Furthermore, it supports checking the reliability of test result data sets as well as their comparability across different QoE studies.}, address = {Mechelen, Belgium}, author = {Hoßfeld, Tobias and Schatz, Raimund and Egger, Sebastian}, booktitle = {QoMEX 2011}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {SOS: The MOS is not enough!}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-422 %A Hoßfeld, Tobias %A Schatz, Raimund %A Egger, Sebastian %B QoMEX 2011 %C Mechelen, Belgium %D 2011 %T SOS: The MOS is not enough! %X When it comes to analysis and interpretation of the results of subjective QoE studies, one often witnesses a lack of attention to the diversity in subjective user ratings. In extreme cases, solely Mean Opinion Scores (MOS) are reported, causing the loss of important information on the user rating diversity. In this paper, we emphasize the importance of considering the Standard deviation of Opinion Scores (SOS) and analyze important characteristics of this measure. As a result, we formulate the SOS hypothesis which postulates a square relationship between the MOS and the SOS. We demonstrate the validity and applicability of the SOS hypothesis for a wide range of studies. The main benefit of the SOS hypothesis is that it allows for a compact, yet still comprehensive statistical summary of subjective user tests. Furthermore, it supports checking the reliability of test result data sets as well as their comparability across different QoE studies.
• Loop-Free Convergence using Ordered FIB Updates: Analysis and Routing Optimization. Hock, David; Hartmann, Matthias; Neubert, Tim; Menth, Michael. In 8th International Workshop on the Design of Reliable Communication Networks (DRCN). Krakow, Poland, 2011.
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  @inproceedings{info3-inproceedings-2011-420, address = {Krakow, Poland}, author = {Hock, David and Hartmann, Matthias and Neubert, Tim and Menth, Michael}, booktitle = {8th International Workshop on the Design of Reliable Communication Networks (DRCN)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Loop-Free Convergence using Ordered FIB Updates: Analysis and Routing Optimization}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-420 %A Hock, David %A Hartmann, Matthias %A Neubert, Tim %A Menth, Michael %B 8th International Workshop on the Design of Reliable Communication Networks (DRCN) %C Krakow, Poland %D 2011 %T Loop-Free Convergence using Ordered FIB Updates: Analysis and Routing Optimization
• The Memory Effect and Its Implications on Web QoE Modeling. Hoßfeld, Tobias; Schatz, Raimund; Biedermann, Sebastian; Platzer, Alexander; Egger, Sebastian; Fiedler, Markus. In 23rd International Teletraffic Congress (ITC 2011). San Francisco, USA, 2011.
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  Quality of Experience (QoE) has gained enormous attention during the recent years. So far, most of the existing QoE research has focused on audio and video streaming applications, although HTTP traffic carries the majority of traffic in the residential broadband Internet. However, existing QoE models for this domain do not consider temporal dynamics or historical experiences of the user's satisfaction while consuming a certain service. This psychological influence factor of past experience is referred to as the memory effect. The first contribution of this paper is the identification of the memory effect as a key influence factor for Web QoE modeling based on subjective user studies. As second contribution, three different QoE models are proposed which consider the implications of the memory effect and imply the required extensions of the basic models. The proposed Web QoE models are described on behalf of a) support vector machines, b) iterative exponential regressions, and c) two-dimensional hidden Markov models.

  @inproceedings{info3-inproceedings-2011-418, abstract = {Quality of Experience (QoE) has gained enormous attention during the recent years. So far, most of the existing QoE research has focused on audio and video streaming applications, although HTTP traffic carries the majority of traffic in the residential broadband Internet. However, existing QoE models for this domain do not consider temporal dynamics or historical experiences of the user's satisfaction while consuming a certain service. This psychological influence factor of past experience is referred to as the memory effect. The first contribution of this paper is the identification of the memory effect as a key influence factor for Web QoE modeling based on subjective user studies. As second contribution, three different QoE models are proposed which consider the implications of the memory effect and imply the required extensions of the basic models. The proposed Web QoE models are described on behalf of a) support vector machines, b) iterative exponential regressions, and c) two-dimensional hidden Markov models.}, address = {San Francisco, USA}, author = {Hoßfeld, Tobias and Schatz, Raimund and Biedermann, Sebastian and Platzer, Alexander and Egger, Sebastian and Fiedler, Markus}, booktitle = {23rd International Teletraffic Congress (ITC 2011)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {The Memory Effect and Its Implications on Web QoE Modeling}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-418 %A Hoßfeld, Tobias %A Schatz, Raimund %A Biedermann, Sebastian %A Platzer, Alexander %A Egger, Sebastian %A Fiedler, Markus %B 23rd International Teletraffic Congress (ITC 2011) %C San Francisco, USA %D 2011 %T The Memory Effect and Its Implications on Web QoE Modeling %X Quality of Experience (QoE) has gained enormous attention during the recent years. So far, most of the existing QoE research has focused on audio and video streaming applications, although HTTP traffic carries the majority of traffic in the residential broadband Internet. However, existing QoE models for this domain do not consider temporal dynamics or historical experiences of the user's satisfaction while consuming a certain service. This psychological influence factor of past experience is referred to as the memory effect. The first contribution of this paper is the identification of the memory effect as a key influence factor for Web QoE modeling based on subjective user studies. As second contribution, three different QoE models are proposed which consider the implications of the memory effect and imply the required extensions of the basic models. The proposed Web QoE models are described on behalf of a) support vector machines, b) iterative exponential regressions, and c) two-dimensional hidden Markov models.
• Modeling of Crowdsourcing Platforms and Granularity of Work Organization in Future Internet. Hoßfeld, Tobias; Hirth, Matthias; Tran-Gia, Phuoc. In International Teletraffic Congress (ITC). San Francisco, USA, 2011.
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  Beside of social media networks, crowdsourcing is one of the emerging new applications and business models in the Future Internet, which can dramatically change the future of work and work organization in the on-line world. The crowdsourcing technology can be viewed as “Human Cloud” technique, in contrast to “Machine Cloud Computing”. Using a crowd with a large number of internationally widespread workers and the flexibility of micro-payment services, crowdsourcing platforms like Amazon’s MTurk and Microworkers can outsource traditional forms of work organization on a microscopic level of granularity to a large, anonymous crowd of workers, the human cloud. In such platforms work or tasks are organized at a finer granularity and jobs are split into micro-tasks that need to be performed by a human cloud. It is a need of analysis to understand the anatomy of such a platform and of models to describe the time-dependent growth of the human cloud, in order to predict the traffic impact of such novel applications and to forecast the growth dynamics. The purpose of this paper is a measurement-based statistical analysis of a crowdsourcing platform, using the Microworkers.com platform as example. The obtained results are then used to model the growth of such fast-changing environments in the Internet using well-known models from biology. Based on the findings from the population growth, we develop a deterministic fluid model which is an extension of the SIR model of epidemics, in order to investigate the platform dynamics.

  @inproceedings{info3-inproceedings-2011-417, abstract = {Beside of social media networks, crowdsourcing is one of the emerging new applications and business models in the Future Internet, which can dramatically change the future of work and work organization in the on-line world. The crowdsourcing technology can be viewed as “Human Cloud” technique, in contrast to “Machine Cloud Computing”. Using a crowd with a large number of internationally widespread workers and the flexibility of micro-payment services, crowdsourcing platforms like Amazon’s MTurk and Microworkers can outsource traditional forms of work organization on a microscopic level of granularity to a large, anonymous crowd of workers, the human cloud. In such platforms work or tasks are organized at a finer granularity and jobs are split into micro-tasks that need to be performed by a human cloud. It is a need of analysis to understand the anatomy of such a platform and of models to describe the time-dependent growth of the human cloud, in order to predict the traffic impact of such novel applications and to forecast the growth dynamics. The purpose of this paper is a measurement-based statistical analysis of a crowdsourcing platform, using the Microworkers.com platform as example. The obtained results are then used to model the growth of such fast-changing environments in the Internet using well-known models from biology. Based on the findings from the population growth, we develop a deterministic fluid model which is an extension of the SIR model of epidemics, in order to investigate the platform dynamics.}, address = {San Francisco, USA}, author = {Hoßfeld, Tobias and Hirth, Matthias and Tran-Gia, Phuoc}, booktitle = {International Teletraffic Congress (ITC)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Modeling of Crowdsourcing Platforms and Granularity of Work Organization in Future Internet}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-417 %A Hoßfeld, Tobias %A Hirth, Matthias %A Tran-Gia, Phuoc %B International Teletraffic Congress (ITC) %C San Francisco, USA %D 2011 %T Modeling of Crowdsourcing Platforms and Granularity of Work Organization in Future Internet %X Beside of social media networks, crowdsourcing is one of the emerging new applications and business models in the Future Internet, which can dramatically change the future of work and work organization in the on-line world. The crowdsourcing technology can be viewed as “Human Cloud” technique, in contrast to “Machine Cloud Computing”. Using a crowd with a large number of internationally widespread workers and the flexibility of micro-payment services, crowdsourcing platforms like Amazon’s MTurk and Microworkers can outsource traditional forms of work organization on a microscopic level of granularity to a large, anonymous crowd of workers, the human cloud. In such platforms work or tasks are organized at a finer granularity and jobs are split into micro-tasks that need to be performed by a human cloud. It is a need of analysis to understand the anatomy of such a platform and of models to describe the time-dependent growth of the human cloud, in order to predict the traffic impact of such novel applications and to forecast the growth dynamics. The purpose of this paper is a measurement-based statistical analysis of a crowdsourcing platform, using the Microworkers.com platform as example. The obtained results are then used to model the growth of such fast-changing environments in the Internet using well-known models from biology. Based on the findings from the population growth, we develop a deterministic fluid model which is an extension of the SIR model of epidemics, in order to investigate the platform dynamics.
• Service Component Mobility Enabled by Network Virtualization. Schlosser, Daniel; Duelli, Michael; Zinner, Thomas; Meier, Sebastian; Wagner, David; Barisch, Marc; Hoffmann, Marco; Kellerer, Wolfgang; Schmid, Matthias. In Euroview 2011. 2011.
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  @inproceedings{info3-inproceedings-2011-429, author = {Schlosser, Daniel and Duelli, Michael and Zinner, Thomas and Meier, Sebastian and Wagner, David and Barisch, Marc and Hoffmann, Marco and Kellerer, Wolfgang and Schmid, Matthias}, booktitle = {Euroview 2011}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Service Component Mobility Enabled by Network Virtualization}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-429 %A Schlosser, Daniel %A Duelli, Michael %A Zinner, Thomas %A Meier, Sebastian %A Wagner, David %A Barisch, Marc %A Hoffmann, Marco %A Kellerer, Wolfgang %A Schmid, Matthias %B Euroview 2011 %D 2011 %T Service Component Mobility Enabled by Network Virtualization
• Application-Aware Self-Optimization of Wireless Mesh Networks with AquareYoum and DES-SERT. Staehle, Barbara; Wamser, Florian; Deschner, Sebastian; Blenk, Andreas; Staehle, Dirk; Hahm, Oliver; Schmittberger, Nicolai; Günes, Mesut. In Euroview 2011. Würzburg, Germany, 2011.
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  @inproceedings{info3-inproceedings-2011-425, address = {Würzburg, Germany}, author = {Staehle, Barbara and Wamser, Florian and Deschner, Sebastian and Blenk, Andreas and Staehle, Dirk and Hahm, Oliver and Schmittberger, Nicolai and Günes, Mesut}, booktitle = {Euroview 2011}, keywords = {demobenefit}, month = {08}, title = {Application-Aware Self-Optimization of Wireless Mesh Networks with AquareYoum and DES-SERT}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-425 %A Staehle, Barbara %A Wamser, Florian %A Deschner, Sebastian %A Blenk, Andreas %A Staehle, Dirk %A Hahm, Oliver %A Schmittberger, Nicolai %A Günes, Mesut %B Euroview 2011 %C Würzburg, Germany %D 2011 %T Application-Aware Self-Optimization of Wireless Mesh Networks with AquareYoum and DES-SERT
• Analysis of web-based video delivery. Metzger, Florian; Rafetseder, Albert; Stezenbach, David; Tutschku, Kurt. In 50th FITCE Congress - "ICT: Bridging an Ever Shifting Digital Divide". 2011.
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  @inproceedings{info3-inproceedings-2011-28, author = {Metzger, Florian and Rafetseder, Albert and Stezenbach, David and Tutschku, Kurt}, booktitle = {50th FITCE Congress - "ICT: Bridging an Ever Shifting Digital Divide"}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Analysis of web-based video delivery}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-28 %A Metzger, Florian %A Rafetseder, Albert %A Stezenbach, David %A Tutschku, Kurt %B 50th FITCE Congress - "ICT: Bridging an Ever Shifting Digital Divide" %D 2011 %T Analysis of web-based video delivery
• Flexible VNE Algorithms Analysis using ALEVIN. Felipe Botero, Juan; Hesselbach, Xavier; Duelli, Michael; Schlosser, Daniel; Fischer, Andreas; de Meer, Hermann. In Euroview 2011. 2011.
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  Network virtualization is recognized as an enabling technology for the Future Internet that overcomes network ossification. However, it introduces a set of challenges. In any network virtualization environment, the problem of optimally mapping virtual demands to physical resources, known as virtual network embedding (VNE), is a crucial challenge. This paper analyses the behaviour of the main algorithms proposed to solve VNE by means of the ALEVIN framework. The VNE algorithms are evaluated with regard to appropriate metrics such as: cost, revenue, and virtual network acceptance ratio. We also analyse the impact of the recently introduced hidden hop demand concept in the performance of the VNE algorithms.

  @inproceedings{info3-inproceedings-2011-427, abstract = {Network virtualization is recognized as an enabling technology for the Future Internet that overcomes network ossification. However, it introduces a set of challenges. In any network virtualization environment, the problem of optimally mapping virtual demands to physical resources, known as virtual network embedding (VNE), is a crucial challenge. This paper analyses the behaviour of the main algorithms proposed to solve VNE by means of the ALEVIN framework. The VNE algorithms are evaluated with regard to appropriate metrics such as: cost, revenue, and virtual network acceptance ratio. We also analyse the impact of the recently introduced hidden hop demand concept in the performance of the VNE algorithms.}, author = {Felipe Botero, Juan and Hesselbach, Xavier and Duelli, Michael and Schlosser, Daniel and Fischer, Andreas and de Meer, Hermann}, booktitle = {Euroview 2011}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Flexible VNE Algorithms Analysis using ALEVIN}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-427 %A Felipe Botero, Juan %A Hesselbach, Xavier %A Duelli, Michael %A Schlosser, Daniel %A Fischer, Andreas %A de Meer, Hermann %B Euroview 2011 %D 2011 %T Flexible VNE Algorithms Analysis using ALEVIN %X Network virtualization is recognized as an enabling technology for the Future Internet that overcomes network ossification. However, it introduces a set of challenges. In any network virtualization environment, the problem of optimally mapping virtual demands to physical resources, known as virtual network embedding (VNE), is a crucial challenge. This paper analyses the behaviour of the main algorithms proposed to solve VNE by means of the ALEVIN framework. The VNE algorithms are evaluated with regard to appropriate metrics such as: cost, revenue, and virtual network acceptance ratio. We also analyse the impact of the recently introduced hidden hop demand concept in the performance of the VNE algorithms.

• Improving the QoE of Citrix Thin Client Users. Schlosser, Daniel; Staehle, Barbara; Binzenhöfer, Andreas; Boder, Björn. In IEEE International Conference on Communications (ICC 2010). Cape Town, South Africa, 2010.
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  During the last years so-called 'Thin Client' architectures have become very popular. Thin Clients are simple end user devices, which are provided with content and services by powerful servers. Originally this concept was developed for Local Area Networks (LANs), which provide a high Quality of Service. If they are used in Wide Area Networks (WANs) they need to be adjusted accordingly in order to guarantee a good Quality of Experience (QoE). In this paper we investigate possibilities for configuring Citrix based Thin Client architectures to improve the QoE in WAN environments. We consider the benefits on the QoE as well as the costs on network layer.

  @inproceedings{info3-inproceedings-2010-385, abstract = {During the last years so-called 'Thin Client' architectures have become very popular. Thin Clients are simple end user devices, which are provided with content and services by powerful servers. Originally this concept was developed for Local Area Networks (LANs), which provide a high Quality of Service. If they are used in Wide Area Networks (WANs) they need to be adjusted accordingly in order to guarantee a good Quality of Experience (QoE). In this paper we investigate possibilities for configuring Citrix based Thin Client architectures to improve the QoE in WAN environments. We consider the benefits on the QoE as well as the costs on network layer.}, address = {Cape Town, South Africa}, author = {Schlosser, Daniel and Staehle, Barbara and Binzenhöfer, Andreas and Boder, Björn}, booktitle = {IEEE International Conference on Communications (ICC 2010)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Improving the QoE of Citrix Thin Client Users}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-385 %A Schlosser, Daniel %A Staehle, Barbara %A Binzenhöfer, Andreas %A Boder, Björn %B IEEE International Conference on Communications (ICC 2010) %C Cape Town, South Africa %D 2010 %T Improving the QoE of Citrix Thin Client Users %X During the last years so-called 'Thin Client' architectures have become very popular. Thin Clients are simple end user devices, which are provided with content and services by powerful servers. Originally this concept was developed for Local Area Networks (LANs), which provide a high Quality of Service. If they are used in Wide Area Networks (WANs) they need to be adjusted accordingly in order to guarantee a good Quality of Experience (QoE). In this paper we investigate possibilities for configuring Citrix based Thin Client architectures to improve the QoE in WAN environments. We consider the benefits on the QoE as well as the costs on network layer.
• Greedy Design of Resilient Multi-Layer Networks. Duelli, Michael; Qin, Xiaohua; Menth, Michael. In 6th Conference on Next Generation Internet Networks (NGI 2010). Paris, France, 2010.
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  In this paper, we propose a deterministic greedy heuristic providing a construction layout for a cost-efficient multi-layer network that is able to carry a given set of traffic demands with and without protection on different layers. We apply the heuristic to different reference network topologies and protection requirements. Evaluations are conducted regarding equipment cost on different layers, blocking probability, path lengths, and number of demands affected by specific failures.

  @inproceedings{info3-inproceedings-2010-382, abstract = {In this paper, we propose a deterministic greedy heuristic providing a construction layout for a cost-efficient multi-layer network that is able to carry a given set of traffic demands with and without protection on different layers. We apply the heuristic to different reference network topologies and protection requirements. Evaluations are conducted regarding equipment cost on different layers, blocking probability, path lengths, and number of demands affected by specific failures.}, address = {Paris, France}, author = {Duelli, Michael and Qin, Xiaohua and Menth, Michael}, booktitle = {6th Conference on Next Generation Internet Networks (NGI 2010)}, keywords = {100get}, month = {06}, title = {Greedy Design of Resilient Multi-Layer Networks}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-382 %A Duelli, Michael %A Qin, Xiaohua %A Menth, Michael %B 6th Conference on Next Generation Internet Networks (NGI 2010) %C Paris, France %D 2010 %T Greedy Design of Resilient Multi-Layer Networks %X In this paper, we propose a deterministic greedy heuristic providing a construction layout for a cost-efficient multi-layer network that is able to carry a given set of traffic demands with and without protection on different layers. We apply the heuristic to different reference network topologies and protection requirements. Evaluations are conducted regarding equipment cost on different layers, blocking probability, path lengths, and number of demands affected by specific failures.
• YoMo: A YouTube Application Comfort Monitoring Tool. Staehle, Barbara; Hirth, Matthias; Pries, Rastin; Wamser, Florian; Staehle, Dirk. In New Dimensions in the Assessment and Support of Quality of Experience for Multimedia Applications. Tampere, Finland, 2010.
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  Out of the large number of multimedia content sharing platforms YouTube is the most popular one. This is reflected by the large number of studies which focus on analyzing YouTube characteristics. Techniques for quantifying the instantaneous YouTube QoE and predicting an imminent QoE degradation have in contrast never been proposed. The latter task is even more important if network management actions shall be carried out to avoid a YouTube QoE degradation. In this work we describe YoMo, a tool which constantly monitors the YouTube application comfort. This measure quantifies the application operation condition and allows a QoE prediction. Experiments show that YoMo is able to exactly anticipate an upcoming YouTube QoE degradation.

  @inproceedings{info3-inproceedings-2010-376, abstract = {Out of the large number of multimedia content sharing platforms YouTube is the most popular one. This is reflected by the large number of studies which focus on analyzing YouTube characteristics. Techniques for quantifying the instantaneous YouTube QoE and predicting an imminent QoE degradation have in contrast never been proposed. The latter task is even more important if network management actions shall be carried out to avoid a YouTube QoE degradation. In this work we describe YoMo, a tool which constantly monitors the YouTube application comfort. This measure quantifies the application operation condition and allows a QoE prediction. Experiments show that YoMo is able to exactly anticipate an upcoming YouTube QoE degradation.}, address = {Tampere, Finland}, author = {Staehle, Barbara and Hirth, Matthias and Pries, Rastin and Wamser, Florian and Staehle, Dirk}, booktitle = {New Dimensions in the Assessment and Support of Quality of Experience for Multimedia Applications}, keywords = {demobenefit}, month = {06}, title = {YoMo: A YouTube Application Comfort Monitoring Tool}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-376 %A Staehle, Barbara %A Hirth, Matthias %A Pries, Rastin %A Wamser, Florian %A Staehle, Dirk %B New Dimensions in the Assessment and Support of Quality of Experience for Multimedia Applications %C Tampere, Finland %D 2010 %T YoMo: A YouTube Application Comfort Monitoring Tool %X Out of the large number of multimedia content sharing platforms YouTube is the most popular one. This is reflected by the large number of studies which focus on analyzing YouTube characteristics. Techniques for quantifying the instantaneous YouTube QoE and predicting an imminent QoE degradation have in contrast never been proposed. The latter task is even more important if network management actions shall be carried out to avoid a YouTube QoE degradation. In this work we describe YoMo, a tool which constantly monitors the YouTube application comfort. This measure quantifies the application operation condition and allows a QoE prediction. Experiments show that YoMo is able to exactly anticipate an upcoming YouTube QoE degradation.
• Impact of Frame Rate and Resolution on Objective QoE Metrics. Zinner, Thomas; Hohlfeld, Oliver; Abboud, Osama; Hoßfeld, Tobias. In International Workshop on Quality of Multimedia Experience, 2010. Trondheim, 2010.
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  Video streaming applications are a major driver for the evolution of the future Internet. In this paper we introduce a framework for QoE management for video streaming systems based on the H.264/SVC codec, the scalable extension of H.264/AVC. A relevant feature is to control the user perceived quality of experience (QoE) by exploiting parameters offered by SVC. A proper design of a control mechanism requires the quantification of the main influence parameters on the QoE. For this purpose, we conducted a measurement study and quantified the influence of i) video resolution, ii) scaling method, iii) video frame rate and iv) video content types on the QoE by means of the SSIM and VQM full-reference metrics. Further, we discuss the trade-off between these different control knobs and their influence on the QoE.

  @inproceedings{info3-inproceedings-2010-378, abstract = {Video streaming applications are a major driver for the evolution of the future Internet. In this paper we introduce a framework for QoE management for video streaming systems based on the H.264/SVC codec, the scalable extension of H.264/AVC. A relevant feature is to control the user perceived quality of experience (QoE) by exploiting parameters offered by SVC. A proper design of a control mechanism requires the quantification of the main influence parameters on the QoE. For this purpose, we conducted a measurement study and quantified the influence of i) video resolution, ii) scaling method, iii) video frame rate and iv) video content types on the QoE by means of the SSIM and VQM full-reference metrics. Further, we discuss the trade-off between these different control knobs and their influence on the QoE.}, address = {Trondheim}, author = {Zinner, Thomas and Hohlfeld, Oliver and Abboud, Osama and Hoßfeld, Tobias}, booktitle = {International Workshop on Quality of Multimedia Experience, 2010}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Impact of Frame Rate and Resolution on Objective QoE Metrics}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-378 %A Zinner, Thomas %A Hohlfeld, Oliver %A Abboud, Osama %A Hoßfeld, Tobias %B International Workshop on Quality of Multimedia Experience, 2010 %C Trondheim %D 2010 %T Impact of Frame Rate and Resolution on Objective QoE Metrics %X Video streaming applications are a major driver for the evolution of the future Internet. In this paper we introduce a framework for QoE management for video streaming systems based on the H.264/SVC codec, the scalable extension of H.264/AVC. A relevant feature is to control the user perceived quality of experience (QoE) by exploiting parameters offered by SVC. A proper design of a control mechanism requires the quantification of the main influence parameters on the QoE. For this purpose, we conducted a measurement study and quantified the influence of i) video resolution, ii) scaling method, iii) video frame rate and iv) video content types on the QoE by means of the SSIM and VQM full-reference metrics. Further, we discuss the trade-off between these different control knobs and their influence on the QoE.
• Controlled vs. Uncontrolled Degradations of QoE – The Provisioning-Delivery Hysteresis in Case of Video. Zinner, Thomas; Hoßfeld, Tobias; Nawaz Minash, Tahir; Fiedler, Markus. In New Dimensions in the Assessment and Support of Quality of Experience (QoE) for Multimedia Applications. Tampere, 2010.
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  This paper applies the recently proposed provisioning-delivery hysteresis for Quality of Experience (QoE) to the case of video. The study is based on evaluations using the Structural Similarity Metric (SSIM) for different versions of a video in terms of resolution on one hand, and suffering from different packet loss ratios on the other hand. Upon translation of the SSIM into MOS, the QoE plotted versus the effective throughput shows the predicted behaviour: a controlled quality and throughput reduction leads to a better user perceived quality than the quality degradation due to packet loss. The results clearly quantify the necessity to control quality, instead of 'getting hit' in an uncontrolled way.

  @inproceedings{info3-inproceedings-2010-375, abstract = {This paper applies the recently proposed provisioning-delivery hysteresis for Quality of Experience (QoE) to the case of video. The study is based on evaluations using the Structural Similarity Metric (SSIM) for different versions of a video in terms of resolution on one hand, and suffering from different packet loss ratios on the other hand. Upon translation of the SSIM into MOS, the QoE plotted versus the effective throughput shows the predicted behaviour: a controlled quality and throughput reduction leads to a better user perceived quality than the quality degradation due to packet loss. The results clearly quantify the necessity to control quality, instead of 'getting hit' in an uncontrolled way.}, address = {Tampere}, author = {Zinner, Thomas and Hoßfeld, Tobias and Nawaz Minash, Tahir and Fiedler, Markus}, booktitle = {New Dimensions in the Assessment and Support of Quality of Experience (QoE) for Multimedia Applications}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Controlled vs. Uncontrolled Degradations of QoE – The Provisioning-Delivery Hysteresis in Case of Video}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-375 %A Zinner, Thomas %A Hoßfeld, Tobias %A Nawaz Minash, Tahir %A Fiedler, Markus %B New Dimensions in the Assessment and Support of Quality of Experience (QoE) for Multimedia Applications %C Tampere %D 2010 %T Controlled vs. Uncontrolled Degradations of QoE – The Provisioning-Delivery Hysteresis in Case of Video %X This paper applies the recently proposed provisioning-delivery hysteresis for Quality of Experience (QoE) to the case of video. The study is based on evaluations using the Structural Similarity Metric (SSIM) for different versions of a video in terms of resolution on one hand, and suffering from different packet loss ratios on the other hand. Upon translation of the SSIM into MOS, the QoE plotted versus the effective throughput shows the predicted behaviour: a controlled quality and throughput reduction leads to a better user perceived quality than the quality degradation due to packet loss. The results clearly quantify the necessity to control quality, instead of 'getting hit' in an uncontrolled way.
• QoE Prediction for Radio Resource Management. Hirth, Matthias; Staehle, Barbara; Wamser, Florian; Pries, Rastin; Staehle, Dirk. In The 6th International ICST Conference on Testbeds and Research Infrastructures for the Development of Networks & Communities (TridentCom 2010). Berlin, Germany, 2010.
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  In this paper, we introduce a monitoring tool which measures application-specific parameters. These parameters are used to predict the QoE and to perform resource management based on QoE thresholds. We demonstrate the tool for YouTube traffic in an IEEE 802.11 mesh network. Thereby, the QoE is based on the player video buffer size and the resource management can include rerouting, throttling of best effort traffic, or a gateway handover.

  @inproceedings{info3-inproceedings-2010-384, abstract = {In this paper, we introduce a monitoring tool which measures application-specific parameters. These parameters are used to predict the QoE and to perform resource management based on QoE thresholds. We demonstrate the tool for YouTube traffic in an IEEE 802.11 mesh network. Thereby, the QoE is based on the player video buffer size and the resource management can include rerouting, throttling of best effort traffic, or a gateway handover.}, address = {Berlin, Germany}, author = {Hirth, Matthias and Staehle, Barbara and Wamser, Florian and Pries, Rastin and Staehle, Dirk}, booktitle = {The 6th International ICST Conference on Testbeds and Research Infrastructures for the Development of Networks & Communities (TridentCom 2010)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {QoE Prediction for Radio Resource Management}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-384 %A Hirth, Matthias %A Staehle, Barbara %A Wamser, Florian %A Pries, Rastin %A Staehle, Dirk %B The 6th International ICST Conference on Testbeds and Research Infrastructures for the Development of Networks & Communities (TridentCom 2010) %C Berlin, Germany %D 2010 %T QoE Prediction for Radio Resource Management %X In this paper, we introduce a monitoring tool which measures application-specific parameters. These parameters are used to predict the QoE and to perform resource management based on QoE thresholds. We demonstrate the tool for YouTube traffic in an IEEE 802.11 mesh network. Thereby, the QoE is based on the player video buffer size and the resource management can include rerouting, throttling of best effort traffic, or a gateway handover.
• Deferring CAPEX Investments in Multi-Layer Networks through IP Traffic-Dependent Expansion Stages. Duelli, Michael; Endler, Anke; Menth, Michael. In 11. ITG-Fachtagung Photonische Netze, pp. 133–138. Leipzig, Germany, 2010.
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  Network design is performed for a traffic load in the future. This traffic load is far greater than traffic loads observed at intermediate stages. In this paper, we propose to plan a multi-layer network for such a future traffic load, but instead of provisioning the full network equipment at once, we suggest to defer the deployment of expensive IP interfaces and other enabling equipment only to stages when they are really needed to carry traffic. We develop an algorithm that concentrates IP traffic at an intermediate stage on a subset of those IP interfaces that are required to carry the full load in the future. This reduces the set of used IP interfaces which need to be installed at intermediate stages, and CAPEX investments for the other equipment can be deferred to the future.

  @inproceedings{info3-inproceedings-2010-374, abstract = {Network design is performed for a traffic load in the future. This traffic load is far greater than traffic loads observed at intermediate stages. In this paper, we propose to plan a multi-layer network for such a future traffic load, but instead of provisioning the full network equipment at once, we suggest to defer the deployment of expensive IP interfaces and other enabling equipment only to stages when they are really needed to carry traffic. We develop an algorithm that concentrates IP traffic at an intermediate stage on a subset of those IP interfaces that are required to carry the full load in the future. This reduces the set of used IP interfaces which need to be installed at intermediate stages, and CAPEX investments for the other equipment can be deferred to the future.}, address = {Leipzig, Germany}, author = {Duelli, Michael and Endler, Anke and Menth, Michael}, booktitle = {11. ITG-Fachtagung Photonische Netze}, keywords = {100get}, month = {05}, pages = {133–138}, title = {Deferring CAPEX Investments in Multi-Layer Networks through IP Traffic-Dependent Expansion Stages}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-374 %A Duelli, Michael %A Endler, Anke %A Menth, Michael %B 11. ITG-Fachtagung Photonische Netze %C Leipzig, Germany %D 2010 %P 133--138 %T Deferring CAPEX Investments in Multi-Layer Networks through IP Traffic-Dependent Expansion Stages %X Network design is performed for a traffic load in the future. This traffic load is far greater than traffic loads observed at intermediate stages. In this paper, we propose to plan a multi-layer network for such a future traffic load, but instead of provisioning the full network equipment at once, we suggest to defer the deployment of expensive IP interfaces and other enabling equipment only to stages when they are really needed to carry traffic. We develop an algorithm that concentrates IP traffic at an intermediate stage on a subset of those IP interfaces that are required to carry the full load in the future. This reduces the set of used IP interfaces which need to be installed at intermediate stages, and CAPEX investments for the other equipment can be deferred to the future.
• StreamSocial: A P2P Streaming System with Social Incentives. Abboud, Osama; Zinner, Thomas; Lidanski, Eduardo; Pussep, Konstantin; Steinmetz, Ralf. In IEEE International Symposium on a World of Wireless Mobile and Multimedia Networks. Montreal, 2010.
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  @inproceedings{info3-inproceedings-2010-380, address = {Montreal}, author = {Abboud, Osama and Zinner, Thomas and Lidanski, Eduardo and Pussep, Konstantin and Steinmetz, Ralf}, booktitle = {IEEE International Symposium on a World of Wireless Mobile and Multimedia Networks}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {StreamSocial: A P2P Streaming System with Social Incentives}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-380 %A Abboud, Osama %A Zinner, Thomas %A Lidanski, Eduardo %A Pussep, Konstantin %A Steinmetz, Ralf %B IEEE International Symposium on a World of Wireless Mobile and Multimedia Networks %C Montreal %D 2010 %T StreamSocial: A P2P Streaming System with Social Incentives
• Effectiveness of Link Cost Optimization for IP Rerouting and IP Fast Reroute. Hock, David; Hartmann, Matthias; Schwartz, Christian; Menth, Michael. In 15th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems and Dependability and Fault Tolerance (MMB & DFT 2010). Essen, Germany, 2010.
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  In this paper, we bring together resilience analysis and routing optimization for IP-based intra-domain networks. When link, node, or multiple failures occur, traffic is rerouted which increases the link load on backup paths and possibly causes congestion. Resilience analysis detects the risk of overload situations a priori based on a large set of most likely failure scenarios. To counteract, the routing can be optimized and configured that such bottlenecks are avoided at least for a smaller set of failure scenarios. In this paper, we demonstrate the effectiveness of this routing optimization in IP networks. We use resilience analysis with suitable aggregate views on relative link loads. Furthermore, we compare conventional IP rerouting with IP fast reroute (IP-FRR) and show that IP-FRR can also significantly profit from routing optimization. This paper reviews major parts of previous publications and presents a new method to visualize and compare the resilience of different routing schemes.

  @inproceedings{info3-inproceedings-2010-364, abstract = {In this paper, we bring together resilience analysis and routing optimization for IP-based intra-domain networks. When link, node, or multiple failures occur, traffic is rerouted which increases the link load on backup paths and possibly causes congestion. Resilience analysis detects the risk of overload situations a priori based on a large set of most likely failure scenarios. To counteract, the routing can be optimized and configured that such bottlenecks are avoided at least for a smaller set of failure scenarios. In this paper, we demonstrate the effectiveness of this routing optimization in IP networks. We use resilience analysis with suitable aggregate views on relative link loads. Furthermore, we compare conventional IP rerouting with IP fast reroute (IP-FRR) and show that IP-FRR can also significantly profit from routing optimization. This paper reviews major parts of previous publications and presents a new method to visualize and compare the resilience of different routing schemes.}, address = {Essen, Germany}, author = {Hock, David and Hartmann, Matthias and Schwartz, Christian and Menth, Michael}, booktitle = {15th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems and Dependability and Fault Tolerance (MMB & DFT 2010)}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Effectiveness of Link Cost Optimization for IP Rerouting and IP Fast Reroute}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-364 %A Hock, David %A Hartmann, Matthias %A Schwartz, Christian %A Menth, Michael %B 15th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems and Dependability and Fault Tolerance (MMB & DFT 2010) %C Essen, Germany %D 2010 %T Effectiveness of Link Cost Optimization for IP Rerouting and IP Fast Reroute %X In this paper, we bring together resilience analysis and routing optimization for IP-based intra-domain networks. When link, node, or multiple failures occur, traffic is rerouted which increases the link load on backup paths and possibly causes congestion. Resilience analysis detects the risk of overload situations a priori based on a large set of most likely failure scenarios. To counteract, the routing can be optimized and configured that such bottlenecks are avoided at least for a smaller set of failure scenarios. In this paper, we demonstrate the effectiveness of this routing optimization in IP networks. We use resilience analysis with suitable aggregate views on relative link loads. Furthermore, we compare conventional IP rerouting with IP fast reroute (IP-FRR) and show that IP-FRR can also significantly profit from routing optimization. This paper reviews major parts of previous publications and presents a new method to visualize and compare the resilience of different routing schemes.
• Soft Frequency Reuse in the Uplink of an OFDMA Network. Wamser, Florian; Mittelstädt, David; Staehle, Dirk. In IEEE VTC Spring 10. Taipei, Taiwan, 2010.
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  The challenges with deploying a static frequency reuse OFDMA mobile communication network in an interference limited environment is that for highly loaded cells, significant regions of coverage will experience high interference levels, resulting in unserviceable low signal-to-interference values. Therefore, interference mitigation approaches as adaptive fractional frequency reuse are considered to tackle the problem. In this paper, different strategies for user and resource allocation are evaluated along with fractional frequency reuse schemes. In contrast to downlink scenarios, we investigate the performance of the OFDMA uplink. It is shown that soft frequency reuse is well-performing in the uplink although it is easy to deploy since it does not rely on resource coordination.

  @inproceedings{info3-inproceedings-2010-370, abstract = {The challenges with deploying a static frequency reuse OFDMA mobile communication network in an interference limited environment is that for highly loaded cells, significant regions of coverage will experience high interference levels, resulting in unserviceable low signal-to-interference values. Therefore, interference mitigation approaches as adaptive fractional frequency reuse are considered to tackle the problem. In this paper, different strategies for user and resource allocation are evaluated along with fractional frequency reuse schemes. In contrast to downlink scenarios, we investigate the performance of the OFDMA uplink. It is shown that soft frequency reuse is well-performing in the uplink although it is easy to deploy since it does not rely on resource coordination.}, address = {Taipei, Taiwan}, author = {Wamser, Florian and Mittelstädt, David and Staehle, Dirk}, booktitle = {IEEE VTC Spring 10}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Soft Frequency Reuse in the Uplink of an OFDMA Network}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-370 %A Wamser, Florian %A Mittelstädt, David %A Staehle, Dirk %B IEEE VTC Spring 10 %C Taipei, Taiwan %D 2010 %T Soft Frequency Reuse in the Uplink of an OFDMA Network %X The challenges with deploying a static frequency reuse OFDMA mobile communication network in an interference limited environment is that for highly loaded cells, significant regions of coverage will experience high interference levels, resulting in unserviceable low signal-to-interference values. Therefore, interference mitigation approaches as adaptive fractional frequency reuse are considered to tackle the problem. In this paper, different strategies for user and resource allocation are evaluated along with fractional frequency reuse schemes. In contrast to downlink scenarios, we investigate the performance of the OFDMA uplink. It is shown that soft frequency reuse is well-performing in the uplink although it is easy to deploy since it does not rely on resource coordination.
• COMCON: Use Cases for Virtual Future Networks. Jarschel, Michael; Kirstädter, Andreas; Kellerer, Wolfgang; Hoffmann, Marco; Hoßfeld, Tobias; Köhler, Stefan; Schlosser, Daniel. In TridentCom 2010. Berlin, 2010.
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  In the Future Internet, a multitude of networks will coexist and complement each other. These networks allow specialization but require isolation of functionalities in order to provide dependable and predictable networks. This allows different networks to run in parallel but isolated from each other. Additionally, network resource scalability is supported to reduce the time and overhead required to introduce new services. The objective of the COMCON (COntrol and Management of COexisting Networks) project is to design novel control and management mechanisms that support the coexistence of networks in a future networking scenario and to illustrate the economic advantages. In this contribution we present three use cases defined in COMCON, which serve as a guideline for our virtual network architecture.

  @inproceedings{info3-inproceedings-2010-383, abstract = {In the Future Internet, a multitude of networks will coexist and complement each other. These networks allow specialization but require isolation of functionalities in order to provide dependable and predictable networks. This allows different networks to run in parallel but isolated from each other. Additionally, network resource scalability is supported to reduce the time and overhead required to introduce new services. The objective of the COMCON (COntrol and Management of COexisting Networks) project is to design novel control and management mechanisms that support the coexistence of networks in a future networking scenario and to illustrate the economic advantages. In this contribution we present three use cases defined in COMCON, which serve as a guideline for our virtual network architecture.}, address = {Berlin}, author = {Jarschel, Michael and Kirstädter, Andreas and Kellerer, Wolfgang and Hoffmann, Marco and Hoßfeld, Tobias and Köhler, Stefan and Schlosser, Daniel}, booktitle = {TridentCom 2010}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {COMCON: Use Cases for Virtual Future Networks}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-383 %A Jarschel, Michael %A Kirstädter, Andreas %A Kellerer, Wolfgang %A Hoffmann, Marco %A Hoßfeld, Tobias %A Köhler, Stefan %A Schlosser, Daniel %B TridentCom 2010 %C Berlin %D 2010 %T COMCON: Use Cases for Virtual Future Networks %X In the Future Internet, a multitude of networks will coexist and complement each other. These networks allow specialization but require isolation of functionalities in order to provide dependable and predictable networks. This allows different networks to run in parallel but isolated from each other. Additionally, network resource scalability is supported to reduce the time and overhead required to introduce new services. The objective of the COMCON (COntrol and Management of COexisting Networks) project is to design novel control and management mechanisms that support the coexistence of networks in a future networking scenario and to illustrate the economic advantages. In this contribution we present three use cases defined in COMCON, which serve as a guideline for our virtual network architecture.
• Optimizing Unique Shortest Paths for Resilient Routing and Fast Reroute in IP-Based Networks. Hock, David; Hartmann, Matthias; Menth, Michael; Schwartz, Christian. In IEEE/IFIP Network Operations and Management Symposium (NOMS). Osaka, Japan, 2010.
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  Intradomain routing in IP networks follows shortest paths according to administrative link costs. When several equalcost shortest paths exist, routers that use equal-cost multipath (ECMP) distribute the traffic over all of them. To produce singleshortest path (SSP) routing, a selection mechanism (tie-breaker) chooses just one of the equal-cost paths. Tie-breakers are poorly standardized and use information that may change over time, which makes SSP routing unpredictable. Therefore, link costs producing unique shortest paths (USP) are preferred. In this paper, we show that optimized SSP routing can lead to significantly higher link utilization than expected in case of non-deterministic tie-breakers. We investigate the impact of the allowed link cost range on the general availability of USP routing. We use a heuristic algorithm to generate link costs for USP routing and to minimize the maximum link utilization in networks with and without failures. Fast reroute (FRR) mechanisms can repair failures faster than conventional IP rerouting by pre-computing shortest backup paths around failed network elements. However, when multiple equal-cost paths exist, the backup path layout is unpredictable. We adapt our heuristic to optimize USP routing for IP-FRR using not-via addresses and MPLS-FRR with facility and oneto- one backup. Finally, we compare the performance of USP with various other routing schemes using realistic Rocketfuel topologies.

  @inproceedings{info3-inproceedings-2010-363, abstract = {Intradomain routing in IP networks follows shortest paths according to administrative link costs. When several equalcost shortest paths exist, routers that use equal-cost multipath (ECMP) distribute the traffic over all of them. To produce singleshortest path (SSP) routing, a selection mechanism (tie-breaker) chooses just one of the equal-cost paths. Tie-breakers are poorly standardized and use information that may change over time, which makes SSP routing unpredictable. Therefore, link costs producing unique shortest paths (USP) are preferred. In this paper, we show that optimized SSP routing can lead to significantly higher link utilization than expected in case of non-deterministic tie-breakers. We investigate the impact of the allowed link cost range on the general availability of USP routing. We use a heuristic algorithm to generate link costs for USP routing and to minimize the maximum link utilization in networks with and without failures. Fast reroute (FRR) mechanisms can repair failures faster than conventional IP rerouting by pre-computing shortest backup paths around failed network elements. However, when multiple equal-cost paths exist, the backup path layout is unpredictable. We adapt our heuristic to optimize USP routing for IP-FRR using not-via addresses and MPLS-FRR with facility and oneto- one backup. Finally, we compare the performance of USP with various other routing schemes using realistic Rocketfuel topologies.}, address = {Osaka, Japan}, author = {Hock, David and Hartmann, Matthias and Menth, Michael and Schwartz, Christian}, booktitle = {IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Optimizing Unique Shortest Paths for Resilient Routing and Fast Reroute in IP-Based Networks}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-363 %A Hock, David %A Hartmann, Matthias %A Menth, Michael %A Schwartz, Christian %B IEEE/IFIP Network Operations and Management Symposium (NOMS) %C Osaka, Japan %D 2010 %T Optimizing Unique Shortest Paths for Resilient Routing and Fast Reroute in IP-Based Networks %X Intradomain routing in IP networks follows shortest paths according to administrative link costs. When several equalcost shortest paths exist, routers that use equal-cost multipath (ECMP) distribute the traffic over all of them. To produce singleshortest path (SSP) routing, a selection mechanism (tie-breaker) chooses just one of the equal-cost paths. Tie-breakers are poorly standardized and use information that may change over time, which makes SSP routing unpredictable. Therefore, link costs producing unique shortest paths (USP) are preferred. In this paper, we show that optimized SSP routing can lead to significantly higher link utilization than expected in case of non-deterministic tie-breakers. We investigate the impact of the allowed link cost range on the general availability of USP routing. We use a heuristic algorithm to generate link costs for USP routing and to minimize the maximum link utilization in networks with and without failures. Fast reroute (FRR) mechanisms can repair failures faster than conventional IP rerouting by pre-computing shortest backup paths around failed network elements. However, when multiple equal-cost paths exist, the backup path layout is unpredictable. We adapt our heuristic to optimize USP routing for IP-FRR using not-via addresses and MPLS-FRR with facility and oneto- one backup. Finally, we compare the performance of USP with various other routing schemes using realistic Rocketfuel topologies.
• Effects of Link Rate Assignment in IEEE 802.11 Mesh Networks. Staehle, Barbara; Staehle, Dirk; Pries, Rastin. In 16th European Wireless Conference. Lucca, Italy, 2010.
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  The IEEE 802.11 standard supports a variety of modulation and coding schemes (MCSs). In 802.11-based wireless mesh networks (WMNs) it is hence possible to adapt the link rate to the channel conditions. In particular, smaller link rates may be accepted for an increased spatial reuse. In an earlier study, we showed that this effect is suitable for increasing the max-min fair share throughput in a WMN operating with a TDMA channel access scheme. In this work, we investigate if the use of smaller link rates is also suitable for increasing the throughput of a WMN using a contention-based channel access mechanism. For this purpose, we analytically derive a guideline for link rate assignment as protection against hidden nodes and compute the costs and benefits of this mechanism in terms of MAC layer efficiency. A simulation study shows however that in a medium sized WMN this strategy is less advantageous than assumed and allows to give advices for practical mesh network deployments.

  @inproceedings{info3-inproceedings-2010-371, abstract = {The IEEE 802.11 standard supports a variety of modulation and coding schemes (MCSs). In 802.11-based wireless mesh networks (WMNs) it is hence possible to adapt the link rate to the channel conditions. In particular, smaller link rates may be accepted for an increased spatial reuse. In an earlier study, we showed that this effect is suitable for increasing the max-min fair share throughput in a WMN operating with a TDMA channel access scheme. In this work, we investigate if the use of smaller link rates is also suitable for increasing the throughput of a WMN using a contention-based channel access mechanism. For this purpose, we analytically derive a guideline for link rate assignment as protection against hidden nodes and compute the costs and benefits of this mechanism in terms of MAC layer efficiency. A simulation study shows however that in a medium sized WMN this strategy is less advantageous than assumed and allows to give advices for practical mesh network deployments.}, address = {Lucca, Italy}, author = {Staehle, Barbara and Staehle, Dirk and Pries, Rastin}, booktitle = {16th European Wireless Conference}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Effects of Link Rate Assignment in IEEE 802.11 Mesh Networks}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-371 %A Staehle, Barbara %A Staehle, Dirk %A Pries, Rastin %B 16th European Wireless Conference %C Lucca, Italy %D 2010 %T Effects of Link Rate Assignment in IEEE 802.11 Mesh Networks %X The IEEE 802.11 standard supports a variety of modulation and coding schemes (MCSs). In 802.11-based wireless mesh networks (WMNs) it is hence possible to adapt the link rate to the channel conditions. In particular, smaller link rates may be accepted for an increased spatial reuse. In an earlier study, we showed that this effect is suitable for increasing the max-min fair share throughput in a WMN operating with a TDMA channel access scheme. In this work, we investigate if the use of smaller link rates is also suitable for increasing the throughput of a WMN using a contention-based channel access mechanism. For this purpose, we analytically derive a guideline for link rate assignment as protection against hidden nodes and compute the costs and benefits of this mechanism in terms of MAC layer efficiency. A simulation study shows however that in a medium sized WMN this strategy is less advantageous than assumed and allows to give advices for practical mesh network deployments.
• Towards QoE Management for Scalable Video Streaming. Zinner, Thomas; Abboud, Osama; Hohlfeld, Oliver; Hoßfeld, Tobias; Tran-Gia, Phuoc. In 21th ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE. Miyazaki, Jap, 2010.
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  Video streaming applications are a major driver for the evolution of the future Internet. In this paper we introduce a framework for QoE management for video streaming systems based on H.264/SVC codec, the scalable extension of H.264/AVC. A relevant feature is to control the user perceived quality of experience (QoE) by exploiting parameters offered by SVC. A proper design of a control mechanisms requires the quantification of the main influence parameters on the QoE. For this purpose, we conducted an extensive measurement study and quantified the influence of i) video resolution, ii) scaling method, iii) network conditions in terms of packet loss and iv) video content types on the QoE by means of the SSIM and PSNR full-reference metrics. Further, we discuss the trade-off between these different control knobs and their influence on the QoE.

  @inproceedings{info3-inproceedings-2010-369, abstract = {Video streaming applications are a major driver for the evolution of the future Internet. In this paper we introduce a framework for QoE management for video streaming systems based on H.264/SVC codec, the scalable extension of H.264/AVC. A relevant feature is to control the user perceived quality of experience (QoE) by exploiting parameters offered by SVC. A proper design of a control mechanisms requires the quantification of the main influence parameters on the QoE. For this purpose, we conducted an extensive measurement study and quantified the influence of i) video resolution, ii) scaling method, iii) network conditions in terms of packet loss and iv) video content types on the QoE by means of the SSIM and PSNR full-reference metrics. Further, we discuss the trade-off between these different control knobs and their influence on the QoE.}, address = {Miyazaki, Jap}, author = {Zinner, Thomas and Abboud, Osama and Hohlfeld, Oliver and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {21th ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Towards QoE Management for Scalable Video Streaming}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-369 %A Zinner, Thomas %A Abboud, Osama %A Hohlfeld, Oliver %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B 21th ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE %C Miyazaki, Jap %D 2010 %T Towards QoE Management for Scalable Video Streaming %X Video streaming applications are a major driver for the evolution of the future Internet. In this paper we introduce a framework for QoE management for video streaming systems based on H.264/SVC codec, the scalable extension of H.264/AVC. A relevant feature is to control the user perceived quality of experience (QoE) by exploiting parameters offered by SVC. A proper design of a control mechanisms requires the quantification of the main influence parameters on the QoE. For this purpose, we conducted an extensive measurement study and quantified the influence of i) video resolution, ii) scaling method, iii) network conditions in terms of packet loss and iv) video content types on the QoE by means of the SSIM and PSNR full-reference metrics. Further, we discuss the trade-off between these different control knobs and their influence on the QoE.
• Quality of Experience-Related Differential Equations and Provisioning-Delivery Hysteresis. Fiedler, Markus; Hoßfeld, Tobias. In to 21st ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE. Phoenix Seagaia Resort, Miyazaki, Japan, 2010.
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  Churn of revenue-generating and dissatisfied users has become a major point of concern for service providers and network operators. As services rely on interconnecting networks, service performance and thus user satisfaction depend on network performance. Consequently, it is of outmost importance to understand the relationships between user perception, captured by quantitative Quality of Experience (QoE) parameters, and network performance, described by Quality of Service (QoS) parameters. This paper provides insights into fundamental relationships between QoE and QoS, formulated as partial differential equations describing changes in QoE with respect to specific QoS parameters. A set of illustrating examples is given. Furthermore, the different impacts of provisioning and degree of success or failure of delivery on QoE are discussed, leading to QoE provisioning-delivery hysteresis. This hysteresis provides a striking motivation for employing elastic adaptation mechanisms to available resources instead of suffering from uncontrolled data loss.

  @inproceedings{info3-inproceedings-2010-366, abstract = {Churn of revenue-generating and dissatisfied users has become a major point of concern for service providers and network operators. As services rely on interconnecting networks, service performance and thus user satisfaction depend on network performance. Consequently, it is of outmost importance to understand the relationships between user perception, captured by quantitative Quality of Experience (QoE) parameters, and network performance, described by Quality of Service (QoS) parameters. This paper provides insights into fundamental relationships between QoE and QoS, formulated as partial differential equations describing changes in QoE with respect to specific QoS parameters. A set of illustrating examples is given. Furthermore, the different impacts of provisioning and degree of success or failure of delivery on QoE are discussed, leading to QoE provisioning-delivery hysteresis. This hysteresis provides a striking motivation for employing elastic adaptation mechanisms to available resources instead of suffering from uncontrolled data loss.}, address = {Phoenix Seagaia Resort, Miyazaki, Japan}, author = {Fiedler, Markus and Hoßfeld, Tobias}, booktitle = {to 21st ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Quality of Experience-Related Differential Equations and Provisioning-Delivery Hysteresis}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-366 %A Fiedler, Markus %A Hoßfeld, Tobias %B to 21st ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE %C Phoenix Seagaia Resort, Miyazaki, Japan %D 2010 %T Quality of Experience-Related Differential Equations and Provisioning-Delivery Hysteresis %X Churn of revenue-generating and dissatisfied users has become a major point of concern for service providers and network operators. As services rely on interconnecting networks, service performance and thus user satisfaction depend on network performance. Consequently, it is of outmost importance to understand the relationships between user perception, captured by quantitative Quality of Experience (QoE) parameters, and network performance, described by Quality of Service (QoS) parameters. This paper provides insights into fundamental relationships between QoE and QoS, formulated as partial differential equations describing changes in QoE with respect to specific QoS parameters. A set of illustrating examples is given. Furthermore, the different impacts of provisioning and degree of success or failure of delivery on QoE are discussed, leading to QoE provisioning-delivery hysteresis. This hysteresis provides a striking motivation for employing elastic adaptation mechanisms to available resources instead of suffering from uncontrolled data loss.
• ResiLyzer: A Tool for Resilience Analysis in Packet-Switched Communication Networks. Hock, David; Menth, Michael; Hartmann, Matthias; Schwartz, Christian; Stezenbach, David. In 15th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems and Dependability and Fault Tolerance (MMB & DFT 2010). Essen, Germany, 2010.
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  We present a tool for the analysis of fault-tolerance in packet-switched communication networks. Network elements like links or routers can fail or unexpected traffic surges may occur. They lead to service disruptions and degradations. Our tool quantifies these risks and presents a comprehensive digest of the results. We explain the core idea of the analysis and illustrate the tool.

  @inproceedings{info3-inproceedings-2010-365, abstract = {We present a tool for the analysis of fault-tolerance in packet-switched communication networks. Network elements like links or routers can fail or unexpected traffic surges may occur. They lead to service disruptions and degradations. Our tool quantifies these risks and presents a comprehensive digest of the results. We explain the core idea of the analysis and illustrate the tool.}, address = {Essen, Germany}, author = {Hock, David and Menth, Michael and Hartmann, Matthias and Schwartz, Christian and Stezenbach, David}, booktitle = {15th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems and Dependability and Fault Tolerance (MMB & DFT 2010)}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {ResiLyzer: A Tool for Resilience Analysis in Packet-Switched Communication Networks}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-365 %A Hock, David %A Menth, Michael %A Hartmann, Matthias %A Schwartz, Christian %A Stezenbach, David %B 15th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems and Dependability and Fault Tolerance (MMB & DFT 2010) %C Essen, Germany %D 2010 %T ResiLyzer: A Tool for Resilience Analysis in Packet-Switched Communication Networks %X We present a tool for the analysis of fault-tolerance in packet-switched communication networks. Network elements like links or routers can fail or unexpected traffic surges may occur. They lead to service disruptions and degradations. Our tool quantifies these risks and presents a comprehensive digest of the results. We explain the core idea of the analysis and illustrate the tool.
• Supporting Scalable Video Codecs in a P2P Video-on-Demand Streaming System. Oechsner, Simon; Zinner, Thomas; Prokopetz, Jochen; Hoßfeld, Tobias. In 21th ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE. Miyazaki, Jap, 2010.
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  There are currently two complementing and concurrent trends in the Internet. The first is the rise of video streaming and especially Video-on-Demand (VoD) as the most popular application for end users, expressed by a continuously increasing amount of video traffic. In this context, P2P is seen as a promising technology for providing video content efficiently to the users while reducing the cost for the content providers. The second trend is the diversification of end user devices used for watching these videos. This is reflected by the Scalable Video Codec (SVC) extension to the state-of-the-art H.264 video codec, which allows for a stream to be separated into substreams of varying quality and size. In this paper, we propose and evaluate a P2P VoD architecture based on the Tribler application which is enhanced to support such a SVC video. Thus, the proposed system is able to adapt the video quality on-the-fly to the network situation and access capabilities of the user devices.

  @inproceedings{info3-inproceedings-2010-368, abstract = {There are currently two complementing and concurrent trends in the Internet. The first is the rise of video streaming and especially Video-on-Demand (VoD) as the most popular application for end users, expressed by a continuously increasing amount of video traffic. In this context, P2P is seen as a promising technology for providing video content efficiently to the users while reducing the cost for the content providers. The second trend is the diversification of end user devices used for watching these videos. This is reflected by the Scalable Video Codec (SVC) extension to the state-of-the-art H.264 video codec, which allows for a stream to be separated into substreams of varying quality and size. In this paper, we propose and evaluate a P2P VoD architecture based on the Tribler application which is enhanced to support such a SVC video. Thus, the proposed system is able to adapt the video quality on-the-fly to the network situation and access capabilities of the user devices.}, address = {Miyazaki, Jap}, author = {Oechsner, Simon and Zinner, Thomas and Prokopetz, Jochen and Hoßfeld, Tobias}, booktitle = {21th ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Supporting Scalable Video Codecs in a P2P Video-on-Demand Streaming System}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-368 %A Oechsner, Simon %A Zinner, Thomas %A Prokopetz, Jochen %A Hoßfeld, Tobias %B 21th ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE %C Miyazaki, Jap %D 2010 %T Supporting Scalable Video Codecs in a P2P Video-on-Demand Streaming System %X There are currently two complementing and concurrent trends in the Internet. The first is the rise of video streaming and especially Video-on-Demand (VoD) as the most popular application for end users, expressed by a continuously increasing amount of video traffic. In this context, P2P is seen as a promising technology for providing video content efficiently to the users while reducing the cost for the content providers. The second trend is the diversification of end user devices used for watching these videos. This is reflected by the Scalable Video Codec (SVC) extension to the state-of-the-art H.264 video codec, which allows for a stream to be separated into substreams of varying quality and size. In this paper, we propose and evaluate a P2P VoD architecture based on the Tribler application which is enhanced to support such a SVC video. Thus, the proposed system is able to adapt the video quality on-the-fly to the network situation and access capabilities of the user devices.
• Starting Up Multi-Gateway WSNs. Staehle, Barbara; Staehle, Dirk. In 6th International Wireless Communications and Mobile Computing Conference. Caen, France, 2010.
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  The Internet connection of wireless sensor networks (WSNs) is in general assured by more than one gateway. Planning or optimizing such multi-gateway WSNs (MWSNs) has lately been the focus of the research community. For this purpose, most researchers assume that each sensor node knows about a path to each gateway node. The question how a MWSN can be efficiently started up, i.e. how the sensor nodes learn about the gateways has in contrast not yet been studied thoroughly. To close this gap, we formally describe the problem of starting up a MWSN and demonstrate the importance of optimizing the start-up phase by comparing the performance of an optimal solution to the performance of less efficient distributed algorithms.

  @inproceedings{info3-inproceedings-2010-372, abstract = {The Internet connection of wireless sensor networks (WSNs) is in general assured by more than one gateway. Planning or optimizing such multi-gateway WSNs (MWSNs) has lately been the focus of the research community. For this purpose, most researchers assume that each sensor node knows about a path to each gateway node. The question how a MWSN can be efficiently started up, i.e. how the sensor nodes learn about the gateways has in contrast not yet been studied thoroughly. To close this gap, we formally describe the problem of starting up a MWSN and demonstrate the importance of optimizing the start-up phase by comparing the performance of an optimal solution to the performance of less efficient distributed algorithms.}, address = {Caen, France}, author = {Staehle, Barbara and Staehle, Dirk}, booktitle = {6th International Wireless Communications and Mobile Computing Conference}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Starting Up Multi-Gateway WSNs}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-372 %A Staehle, Barbara %A Staehle, Dirk %B 6th International Wireless Communications and Mobile Computing Conference %C Caen, France %D 2010 %T Starting Up Multi-Gateway WSNs %X The Internet connection of wireless sensor networks (WSNs) is in general assured by more than one gateway. Planning or optimizing such multi-gateway WSNs (MWSNs) has lately been the focus of the research community. For this purpose, most researchers assume that each sensor node knows about a path to each gateway node. The question how a MWSN can be efficiently started up, i.e. how the sensor nodes learn about the gateways has in contrast not yet been studied thoroughly. To close this gap, we formally describe the problem of starting up a MWSN and demonstrate the importance of optimizing the start-up phase by comparing the performance of an optimal solution to the performance of less efficient distributed algorithms.
• Max-Min Fair Throughput in Multi-Gateway Multi-Rate Mesh Networks. Staehle, Dirk; Staehle, Barbara; Pries, Rastin. In IEEE VTC Spring 10. Taipei, Taiwan, 2010.
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  The problem how to determine the capacity of and achieve fairness in mesh networks is one of the key topics in practical and theoretical research on mesh networks. Max-min fairness is one way to define fairness and several algorithms how to compute max-min fair rate allocations are already published. In this paper we make two major contributions to this area of research: First, we formulate an algorithm achieving max-min fairness among end-to-end flows based on the effective load of a collision domain. This allows us to determine max-min fair rate allocations in a multi-gateway, multi-channel mesh network with equal rates for all links. Second, we extend this algorithm for heterogeneous link rates.

  @inproceedings{info3-inproceedings-2010-367, abstract = {The problem how to determine the capacity of and achieve fairness in mesh networks is one of the key topics in practical and theoretical research on mesh networks. Max-min fairness is one way to define fairness and several algorithms how to compute max-min fair rate allocations are already published. In this paper we make two major contributions to this area of research: First, we formulate an algorithm achieving max-min fairness among end-to-end flows based on the effective load of a collision domain. This allows us to determine max-min fair rate allocations in a multi-gateway, multi-channel mesh network with equal rates for all links. Second, we extend this algorithm for heterogeneous link rates.}, address = {Taipei, Taiwan}, author = {Staehle, Dirk and Staehle, Barbara and Pries, Rastin}, booktitle = {IEEE VTC Spring 10}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Max-Min Fair Throughput in Multi-Gateway Multi-Rate Mesh Networks}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-367 %A Staehle, Dirk %A Staehle, Barbara %A Pries, Rastin %B IEEE VTC Spring 10 %C Taipei, Taiwan %D 2010 %T Max-Min Fair Throughput in Multi-Gateway Multi-Rate Mesh Networks %X The problem how to determine the capacity of and achieve fairness in mesh networks is one of the key topics in practical and theoretical research on mesh networks. Max-min fairness is one way to define fairness and several algorithms how to compute max-min fair rate allocations are already published. In this paper we make two major contributions to this area of research: First, we formulate an algorithm achieving max-min fairness among end-to-end flows based on the effective load of a collision domain. This allows us to determine max-min fair rate allocations in a multi-gateway, multi-channel mesh network with equal rates for all links. Second, we extend this algorithm for heterogeneous link rates.
• Application- and Context-Aware Radio Resource Management for Future Wireless Networks. Staehle, Barbara; Wamser, Florian; Pries, Rastin; Staehle, Dirk; Mannweiler, Christian; Klein, Andreas; Schneider, Jörg; Schotten, Hans D. In EuroView2010, pp. 143–144. Würzburg, Germany, 2010.
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  @inproceedings{info3-inproceedings-2010-393, address = {Würzburg, Germany}, author = {Staehle, Barbara and Wamser, Florian and Pries, Rastin and Staehle, Dirk and Mannweiler, Christian and Klein, Andreas and Schneider, Jörg and Schotten, Hans D.}, booktitle = {EuroView2010}, keywords = {sys:hidden:inproceedings}, month = {08}, pages = {143-144}, title = {Application- and Context-Aware Radio Resource Management for Future Wireless Networks}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-393 %A Staehle, Barbara %A Wamser, Florian %A Pries, Rastin %A Staehle, Dirk %A Mannweiler, Christian %A Klein, Andreas %A Schneider, Jörg %A Schotten, Hans D. %B EuroView2010 %C Würzburg, Germany %D 2010 %P 143-144 %T Application- and Context-Aware Radio Resource Management for Future Wireless Networks
• Using Concurrent Multipath Transmission for Transport Virtualization: Analyzing Path Selection. Zinner, Thomas; Tutschku, Kurt; Nakao, Akihiro; Tran-Gia, Phuoc. In Proceedings of the 22nd International Teletraffic Congress (ITC). Amsterdam, Netherlands, 2010.
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  The concept of Transport Virtualization (TV) enhances the capabilities of future networks. TV enables transport mechanisms with arbitrary resource usage independent of the underlying transport system. The simplest form of TV can be achieved by collecting multiple transport resources (even from different virtual networks or providers) and selecting the best resources for exclusive or concurrent use. However, the selection and application of concurrent paths is complex and its impact on the transmission is non-intuitive. Path length diversity of different concurrent paths inevitably introduces out-of-order packet delivery.We present and discuss a mathematical model for the analysis of the fundamental behavior and influence factors for packet re-ordering in concurrent multipath transmissions. Our model facilitates the understanding of path selection algorithms for multipath transport virtualization.

  @inproceedings{info3-inproceedings-2010-379, abstract = {The concept of Transport Virtualization (TV) enhances the capabilities of future networks. TV enables transport mechanisms with arbitrary resource usage independent of the underlying transport system. The simplest form of TV can be achieved by collecting multiple transport resources (even from different virtual networks or providers) and selecting the best resources for exclusive or concurrent use. However, the selection and application of concurrent paths is complex and its impact on the transmission is non-intuitive. Path length diversity of different concurrent paths inevitably introduces out-of-order packet delivery.We present and discuss a mathematical model for the analysis of the fundamental behavior and influence factors for packet re-ordering in concurrent multipath transmissions. Our model facilitates the understanding of path selection algorithms for multipath transport virtualization.}, address = {Amsterdam, Netherlands}, author = {Zinner, Thomas and Tutschku, Kurt and Nakao, Akihiro and Tran-Gia, Phuoc}, booktitle = {Proceedings of the 22nd International Teletraffic Congress (ITC)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Using Concurrent Multipath Transmission for Transport Virtualization: Analyzing Path Selection}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-379 %A Zinner, Thomas %A Tutschku, Kurt %A Nakao, Akihiro %A Tran-Gia, Phuoc %B Proceedings of the 22nd International Teletraffic Congress (ITC) %C Amsterdam, Netherlands %D 2010 %T Using Concurrent Multipath Transmission for Transport Virtualization: Analyzing Path Selection %X The concept of Transport Virtualization (TV) enhances the capabilities of future networks. TV enables transport mechanisms with arbitrary resource usage independent of the underlying transport system. The simplest form of TV can be achieved by collecting multiple transport resources (even from different virtual networks or providers) and selecting the best resources for exclusive or concurrent use. However, the selection and application of concurrent paths is complex and its impact on the transmission is non-intuitive. Path length diversity of different concurrent paths inevitably introduces out-of-order packet delivery.We present and discuss a mathematical model for the analysis of the fundamental behavior and influence factors for packet re-ordering in concurrent multipath transmissions. Our model facilitates the understanding of path selection algorithms for multipath transport virtualization.
• A Use Case Driven Approach to Network Virtualization. Schlosser, Daniel; Jarschel, Michael; Duelli, Michael; Hoßfeld, Tobias; Hoffmann, Klaus; Hoffmann, Marco; Jochen Morper, Hans; Jurca, Dan; Khan, Ashiq. In accepted at IEEE Kaleidoscope 2010, published via OPUS Würzburg under OpenAccess. Würzburg, 2010.
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  In today's Internet, services are very different in their requirements on the underlying transport network. In the future, this diversity will increase and it will be more difficult to accommodate all services in a single network. A possible approach to cope with this diversity within future networks is the introduction of support for running isolated networks for different services on top of a single shared physical substrate. This would also enable easy network management and ensure an economically sound operation. End-customers will readily adopt this approach as it enables new and innovative services without being expensive. In order to arrive at a concept that enables this kind of network, it needs to be designed around and constantly checked against realistic use cases. In this contribution, we present three use cases for future networks. We describe functional blocks of a virtual network architecture, which are necessary to support these use cases within the network. Furthermore, we discuss the interfaces needed between the functional blocks and consider standardization issues that arise in order to achieve a global consistent control and management structure of virtual networks.

  @inproceedings{info3-inproceedings-2010-412, abstract = {In today's Internet, services are very different in their requirements on the underlying transport network. In the future, this diversity will increase and it will be more difficult to accommodate all services in a single network. A possible approach to cope with this diversity within future networks is the introduction of support for running isolated networks for different services on top of a single shared physical substrate. This would also enable easy network management and ensure an economically sound operation. End-customers will readily adopt this approach as it enables new and innovative services without being expensive. In order to arrive at a concept that enables this kind of network, it needs to be designed around and constantly checked against realistic use cases. In this contribution, we present three use cases for future networks. We describe functional blocks of a virtual network architecture, which are necessary to support these use cases within the network. Furthermore, we discuss the interfaces needed between the functional blocks and consider standardization issues that arise in order to achieve a global consistent control and management structure of virtual networks.}, address = {Würzburg}, author = {Schlosser, Daniel and Jarschel, Michael and Duelli, Michael and Hoßfeld, Tobias and Hoffmann, Klaus and Hoffmann, Marco and Jochen Morper, Hans and Jurca, Dan and Khan, Ashiq}, booktitle = {accepted at IEEE Kaleidoscope 2010, published via OPUS Würzburg under OpenAccess}, keywords = {sys:hidden:inproceedings}, month = 12, title = {A Use Case Driven Approach to Network Virtualization}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-412 %A Schlosser, Daniel %A Jarschel, Michael %A Duelli, Michael %A Hoßfeld, Tobias %A Hoffmann, Klaus %A Hoffmann, Marco %A Jochen Morper, Hans %A Jurca, Dan %A Khan, Ashiq %B accepted at IEEE Kaleidoscope 2010, published via OPUS Würzburg under OpenAccess %C Würzburg %D 2010 %T A Use Case Driven Approach to Network Virtualization %X In today's Internet, services are very different in their requirements on the underlying transport network. In the future, this diversity will increase and it will be more difficult to accommodate all services in a single network. A possible approach to cope with this diversity within future networks is the introduction of support for running isolated networks for different services on top of a single shared physical substrate. This would also enable easy network management and ensure an economically sound operation. End-customers will readily adopt this approach as it enables new and innovative services without being expensive. In order to arrive at a concept that enables this kind of network, it needs to be designed around and constantly checked against realistic use cases. In this contribution, we present three use cases for future networks. We describe functional blocks of a virtual network architecture, which are necessary to support these use cases within the network. Furthermore, we discuss the interfaces needed between the functional blocks and consider standardization issues that arise in order to achieve a global consistent control and management structure of virtual networks.
• Performance Evaluation of P2P Caches: Flash-Crowd Case. Chołda, Piotr; Domzał, Jerzy; Wojcik, Robert; Stankiewicz, Rafał; Lehrieder, Frank; Hoßfeld, Tobias; Oechsner, Simon; Singeorzan, Vlad. In Australasian Telecommunication Networks and Applications Conference (ATNAC) 2010. Auckland, New Zealand, 2010.
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  Peer-to-peer (P2P) based content distribution networks (CDNs), e.g., BitTorrent, are widely used in the today’s Internet. Since all peers interested in a specific content provide storage and upload capacity those CDNs facilitate a cheap and easy distribution of large amounts of data. However, they generate a lot of costs for Internet Service Providers (ISPs) as normal users also act as a source for downloads. One option for ISPs to encounter the problem of the costly inter-domain traffic is to establish P2P caches. In this study we investigate the potential of those caches in flash-crowd scenarios, i.e., when a large number of peers tries to download the content at the same time. To that end, we perform simulations as well as experiments with real BitTorrent clients. The evaluation shows that ISPs as well as P2P users will benefit from the use of caches.

  @inproceedings{info3-inproceedings-2010-395, abstract = {Peer-to-peer (P2P) based content distribution networks (CDNs), e.g., BitTorrent, are widely used in the today’s Internet. Since all peers interested in a specific content provide storage and upload capacity those CDNs facilitate a cheap and easy distribution of large amounts of data. However, they generate a lot of costs for Internet Service Providers (ISPs) as normal users also act as a source for downloads. One option for ISPs to encounter the problem of the costly inter-domain traffic is to establish P2P caches. In this study we investigate the potential of those caches in flash-crowd scenarios, i.e., when a large number of peers tries to download the content at the same time. To that end, we perform simulations as well as experiments with real BitTorrent clients. The evaluation shows that ISPs as well as P2P users will benefit from the use of caches.}, address = {Auckland, New Zealand}, author = {Chołda, Piotr and Domzał, Jerzy and Wojcik, Robert and Stankiewicz, Rafał and Lehrieder, Frank and Hoßfeld, Tobias and Oechsner, Simon and Singeorzan, Vlad}, booktitle = {Australasian Telecommunication Networks and Applications Conference (ATNAC) 2010}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Performance Evaluation of P2P Caches: Flash-Crowd Case}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-395 %A Chołda, Piotr %A Domzał, Jerzy %A Wojcik, Robert %A Stankiewicz, Rafał %A Lehrieder, Frank %A Hoßfeld, Tobias %A Oechsner, Simon %A Singeorzan, Vlad %B Australasian Telecommunication Networks and Applications Conference (ATNAC) 2010 %C Auckland, New Zealand %D 2010 %T Performance Evaluation of P2P Caches: Flash-Crowd Case %X Peer-to-peer (P2P) based content distribution networks (CDNs), e.g., BitTorrent, are widely used in the today’s Internet. Since all peers interested in a specific content provide storage and upload capacity those CDNs facilitate a cheap and easy distribution of large amounts of data. However, they generate a lot of costs for Internet Service Providers (ISPs) as normal users also act as a source for downloads. One option for ISPs to encounter the problem of the costly inter-domain traffic is to establish P2P caches. In this study we investigate the potential of those caches in flash-crowd scenarios, i.e., when a large number of peers tries to download the content at the same time. To that end, we perform simulations as well as experiments with real BitTorrent clients. The evaluation shows that ISPs as well as P2P users will benefit from the use of caches.
• Monitoring the User Perceived Quality of SILK-Based Voice Calls. Schlosser, Daniel; Jarschel, Michael; Burger, Valentin; Pries, Rastin. In Australasian Telecommunication Networks and Applications Conference (ATNAC 2010). Auckland, New Zealand, 2010.
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  Quality measurements are required to support VoIP traffic in the Internet. The widely used average Mean Opinion Score is, however, not sufficient for this task. In this paper, we provide a detailed analysis of the Skype SILK codec and compare it with the iLBC and GSM codec. The results show that the SILK codec is superior to the other codecs in scenarios with random and bulk packet loss. This increased tolerance of packet loss enables the option of QoE Monitoring under reasonable network conditions. From analysis, we derive an estimation, which can be used to monitor the MOS value of the users in the worst case. Furthermore, we show how sampling can effectively decrease the required measurement effort. This work was funded by the Federal Ministry of Education and Research of the Federal Republic of Germany (Förderkennzeichen 01BK0917, GLab). The authors alone are responsible for the content of the paper.

  @inproceedings{info3-inproceedings-2010-399, abstract = {Quality measurements are required to support VoIP traffic in the Internet. The widely used average Mean Opinion Score is, however, not sufficient for this task. In this paper, we provide a detailed analysis of the Skype SILK codec and compare it with the iLBC and GSM codec. The results show that the SILK codec is superior to the other codecs in scenarios with random and bulk packet loss. This increased tolerance of packet loss enables the option of QoE Monitoring under reasonable network conditions. From analysis, we derive an estimation, which can be used to monitor the MOS value of the users in the worst case. Furthermore, we show how sampling can effectively decrease the required measurement effort. This work was funded by the Federal Ministry of Education and Research of the Federal Republic of Germany (Förderkennzeichen 01BK0917, GLab). The authors alone are responsible for the content of the paper.}, address = {Auckland, New Zealand}, author = {Schlosser, Daniel and Jarschel, Michael and Burger, Valentin and Pries, Rastin}, booktitle = {Australasian Telecommunication Networks and Applications Conference (ATNAC 2010)}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Monitoring the User Perceived Quality of SILK-Based Voice Calls}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-399 %A Schlosser, Daniel %A Jarschel, Michael %A Burger, Valentin %A Pries, Rastin %B Australasian Telecommunication Networks and Applications Conference (ATNAC 2010) %C Auckland, New Zealand %D 2010 %T Monitoring the User Perceived Quality of SILK-Based Voice Calls %X Quality measurements are required to support VoIP traffic in the Internet. The widely used average Mean Opinion Score is, however, not sufficient for this task. In this paper, we provide a detailed analysis of the Skype SILK codec and compare it with the iLBC and GSM codec. The results show that the SILK codec is superior to the other codecs in scenarios with random and bulk packet loss. This increased tolerance of packet loss enables the option of QoE Monitoring under reasonable network conditions. From analysis, we derive an estimation, which can be used to monitor the MOS value of the users in the worst case. Furthermore, we show how sampling can effectively decrease the required measurement effort. This work was funded by the Federal Ministry of Education and Research of the Federal Republic of Germany (Förderkennzeichen 01BK0917, GLab). The authors alone are responsible for the content of the paper.
• NAT Traversal for LISP Mobile Node. Klein, Dominik; Hartmann, Matthias; Menth, Michael. In ACM CoNEXT workshop Re-Architecting the Internet (ReArch). Philadelphia, PA, USA, 2010.
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  The Locator/ID Separation Protocol (LISP) is currently being developed and standardized in the IETF aiming to solve the Internet's routing scaling problem. It separates global routing in the Internet from local routing in end-user networks (so-called LISP-domains). It also provides additional benefits like simplified multihoming or the avoidance of network renumbering. The basic LISP architecture does not support mobility. Recently, the mobility extension LISP Mobile Node (LISP-MN) was presented. It describes a mechanism that enables LISP mobile nodes to roam into LISP and non-LISP networks while being reachable under the same identifier address. Currently, LISP-MN does not support networks that use network address translation (NAT). In this paper, we present a NAT traversal mechanism for LISP mobile nodes and a slight adaptation which is also applicable to stationary LISP domains behind a NAT.

  @inproceedings{info3-inproceedings-2010-398, abstract = {The Locator/ID Separation Protocol (LISP) is currently being developed and standardized in the IETF aiming to solve the Internet's routing scaling problem. It separates global routing in the Internet from local routing in end-user networks (so-called LISP-domains). It also provides additional benefits like simplified multihoming or the avoidance of network renumbering. The basic LISP architecture does not support mobility. Recently, the mobility extension LISP Mobile Node (LISP-MN) was presented. It describes a mechanism that enables LISP mobile nodes to roam into LISP and non-LISP networks while being reachable under the same identifier address. Currently, LISP-MN does not support networks that use network address translation (NAT). In this paper, we present a NAT traversal mechanism for LISP mobile nodes and a slight adaptation which is also applicable to stationary LISP domains behind a NAT.}, address = {Philadelphia, PA, USA}, author = {Klein, Dominik and Hartmann, Matthias and Menth, Michael}, booktitle = {ACM CoNEXT workshop Re-Architecting the Internet (ReArch)}, keywords = {sys:hidden:inproceedings}, month = 11, title = {NAT Traversal for LISP Mobile Node}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-398 %A Klein, Dominik %A Hartmann, Matthias %A Menth, Michael %B ACM CoNEXT workshop Re-Architecting the Internet (ReArch) %C Philadelphia, PA, USA %D 2010 %T NAT Traversal for LISP Mobile Node %X The Locator/ID Separation Protocol (LISP) is currently being developed and standardized in the IETF aiming to solve the Internet's routing scaling problem. It separates global routing in the Internet from local routing in end-user networks (so-called LISP-domains). It also provides additional benefits like simplified multihoming or the avoidance of network renumbering. The basic LISP architecture does not support mobility. Recently, the mobility extension LISP Mobile Node (LISP-MN) was presented. It describes a mechanism that enables LISP mobile nodes to roam into LISP and non-LISP networks while being reachable under the same identifier address. Currently, LISP-MN does not support networks that use network address translation (NAT). In this paper, we present a NAT traversal mechanism for LISP mobile nodes and a slight adaptation which is also applicable to stationary LISP domains behind a NAT.
• Advanced Interference Mitigation with Frequency Reuse Schemes in the IEEE 802.16m Uplink. Wamser, Florian; Mittelstädt, David; Staehle, Dirk; Tran-Gia, Phuoc. In ACM MSWIM 2010, pp. 132–139. Bodrum, Turkey, 2010.
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  Fractional frequency reuse is one of the key interference mitigation schemes of the IEEE 802.16m draft standard. This paper proposes a resource allocation strategy for the uplink fractional frequency reuse in the variant soft frequency reuse. Soft frequency reuse means that the resources of every sector are separated into a home partition and two side partitions. While resources of the home partition may be allocated to all users, resources of the side partitions are available for cell center users only. The main contribution of this paper is to use the most robust and power-efficient modulation and coding schemes on the side partitions as long as resources are available. A simulation study shows that with non-saturated users the system capacity can be increased when preferring power-efficient modulation and coding schemes on the side partitions.

  @inproceedings{info3-inproceedings-2010-394, abstract = {Fractional frequency reuse is one of the key interference mitigation schemes of the IEEE 802.16m draft standard. This paper proposes a resource allocation strategy for the uplink fractional frequency reuse in the variant soft frequency reuse. Soft frequency reuse means that the resources of every sector are separated into a home partition and two side partitions. While resources of the home partition may be allocated to all users, resources of the side partitions are available for cell center users only. The main contribution of this paper is to use the most robust and power-efficient modulation and coding schemes on the side partitions as long as resources are available. A simulation study shows that with non-saturated users the system capacity can be increased when preferring power-efficient modulation and coding schemes on the side partitions.}, address = {Bodrum, Turkey}, author = {Wamser, Florian and Mittelstädt, David and Staehle, Dirk and Tran-Gia, Phuoc}, booktitle = {ACM MSWIM 2010}, keywords = {sys:hidden:inproceedings}, month = 10, pages = {132-139}, title = {Advanced Interference Mitigation with Frequency Reuse Schemes in the IEEE 802.16m Uplink}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-394 %A Wamser, Florian %A Mittelstädt, David %A Staehle, Dirk %A Tran-Gia, Phuoc %B ACM MSWIM 2010 %C Bodrum, Turkey %D 2010 %P 132-139 %T Advanced Interference Mitigation with Frequency Reuse Schemes in the IEEE 802.16m Uplink %X Fractional frequency reuse is one of the key interference mitigation schemes of the IEEE 802.16m draft standard. This paper proposes a resource allocation strategy for the uplink fractional frequency reuse in the variant soft frequency reuse. Soft frequency reuse means that the resources of every sector are separated into a home partition and two side partitions. While resources of the home partition may be allocated to all users, resources of the side partitions are available for cell center users only. The main contribution of this paper is to use the most robust and power-efficient modulation and coding schemes on the side partitions as long as resources are available. A simulation study shows that with non-saturated users the system capacity can be increased when preferring power-efficient modulation and coding schemes on the side partitions.
• On the Potential of IEEE 802.11s Intra-Mesh Congestion Control. Fu, Desheng; Staehle, Barbara; Pries, Rastin; Staehle, Dirk. In 13-th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2010). Bodrum, Turkey, 2010.
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  IEEE 802.11s is an emerging IEEE 802.11 amendment, aiming at standardizing wireless mesh networking. As congestion is a major problem in wireless mesh networks, IEEE 802.11s addresses this problem by introducing the intra-mesh congestion control. In order to explore the potential of this mechanism, we describe two different IEEE 802.11s compliant congestion control mechanisms and discuss their respective benefits and limitations. Results from a simulative evaluation demonstrate that intra-mesh congestion control is suitable for avoiding the loss of packets which have already been forwarded over the air interface and, if appropriately implemented, increases the overall network throughput. The results do however also point out the limitations of the proposed IEEE 802.11s congestion notification format.

  @inproceedings{info3-inproceedings-2010-390, abstract = {IEEE 802.11s is an emerging IEEE 802.11 amendment, aiming at standardizing wireless mesh networking. As congestion is a major problem in wireless mesh networks, IEEE 802.11s addresses this problem by introducing the intra-mesh congestion control. In order to explore the potential of this mechanism, we describe two different IEEE 802.11s compliant congestion control mechanisms and discuss their respective benefits and limitations. Results from a simulative evaluation demonstrate that intra-mesh congestion control is suitable for avoiding the loss of packets which have already been forwarded over the air interface and, if appropriately implemented, increases the overall network throughput. The results do however also point out the limitations of the proposed IEEE 802.11s congestion notification format.}, address = {Bodrum, Turkey}, author = {Fu, Desheng and Staehle, Barbara and Pries, Rastin and Staehle, Dirk}, booktitle = {13-th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2010)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {On the Potential of IEEE 802.11s Intra-Mesh Congestion Control}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-390 %A Fu, Desheng %A Staehle, Barbara %A Pries, Rastin %A Staehle, Dirk %B 13-th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2010) %C Bodrum, Turkey %D 2010 %T On the Potential of IEEE 802.11s Intra-Mesh Congestion Control %X IEEE 802.11s is an emerging IEEE 802.11 amendment, aiming at standardizing wireless mesh networking. As congestion is a major problem in wireless mesh networks, IEEE 802.11s addresses this problem by introducing the intra-mesh congestion control. In order to explore the potential of this mechanism, we describe two different IEEE 802.11s compliant congestion control mechanisms and discuss their respective benefits and limitations. Results from a simulative evaluation demonstrate that intra-mesh congestion control is suitable for avoiding the loss of packets which have already been forwarded over the air interface and, if appropriately implemented, increases the overall network throughput. The results do however also point out the limitations of the proposed IEEE 802.11s congestion notification format.
• Genetic Algorithms for WMN Planning. Pries, Rastin; Wendel, Viktor; Staehle, Barbara; Staehle, Dirk. In 13-th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2010). Bodrum, Turkey, 2010.
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  The complex multi-hop structure of WMNs requires a careful network planning. In this paper, we investigate the usability of Genetic Algorithms (GAs) for such a planning approach. The simplicity of GAs allow us to examine a large number of network configurations in order to optimize the network throughput and to fairly distribute the resources. This is achieved with a max-min fair share throughput distribution and by evaluating node positions, routing configurations, and channel assignments. We adapt standard genetic operators and evaluate the influence of the operators on the performance. The results show that GAs are well-suited for planning WMNs.

  @inproceedings{info3-inproceedings-2010-391, abstract = {The complex multi-hop structure of WMNs requires a careful network planning. In this paper, we investigate the usability of Genetic Algorithms (GAs) for such a planning approach. The simplicity of GAs allow us to examine a large number of network configurations in order to optimize the network throughput and to fairly distribute the resources. This is achieved with a max-min fair share throughput distribution and by evaluating node positions, routing configurations, and channel assignments. We adapt standard genetic operators and evaluate the influence of the operators on the performance. The results show that GAs are well-suited for planning WMNs.}, address = {Bodrum, Turkey}, author = {Pries, Rastin and Wendel, Viktor and Staehle, Barbara and Staehle, Dirk}, booktitle = {13-th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2010)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Genetic Algorithms for WMN Planning}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-391 %A Pries, Rastin %A Wendel, Viktor %A Staehle, Barbara %A Staehle, Dirk %B 13-th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2010) %C Bodrum, Turkey %D 2010 %T Genetic Algorithms for WMN Planning %X The complex multi-hop structure of WMNs requires a careful network planning. In this paper, we investigate the usability of Genetic Algorithms (GAs) for such a planning approach. The simplicity of GAs allow us to examine a large number of network configurations in order to optimize the network throughput and to fairly distribute the resources. This is achieved with a max-min fair share throughput distribution and by evaluating node positions, routing configurations, and channel assignments. We adapt standard genetic operators and evaluate the influence of the operators on the performance. The results show that GAs are well-suited for planning WMNs.
• A QoE-Aware P2P Streaming System based on Scalable Video Coding. Abboud, Osama; Zinner, Thomas; Pussep, Konstantin; Oechsner, Simon; Steinmetz, Ralf; Tran-Gia, Phuoc. In 10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010. Delft, Netherlands, 2010.
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  @inproceedings{info3-inproceedings-2010-392, address = {Delft, Netherlands}, author = {Abboud, Osama and Zinner, Thomas and Pussep, Konstantin and Oechsner, Simon and Steinmetz, Ralf and Tran-Gia, Phuoc}, booktitle = {10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {A QoE-Aware P2P Streaming System based on Scalable Video Coding}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-392 %A Abboud, Osama %A Zinner, Thomas %A Pussep, Konstantin %A Oechsner, Simon %A Steinmetz, Ralf %A Tran-Gia, Phuoc %B 10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010 %C Delft, Netherlands %D 2010 %T A QoE-Aware P2P Streaming System based on Scalable Video Coding
• Improvements to LISP Mobile Node. Menth, Michael; Klein, Dominik; Hartmann, Matthias. In 22nd International Teletraffic Congress (ITC). Amsterdam, The Netherlands, 2010.
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  The Locator/Identifier Separation Protocol (LISP) is a new routing architecture for the Internet that separates local and global routing. It offers more flexibility to edge networks and has the potential to reduce the growths of the BGP routing tables. Recently, a concept for mobility in LISP (LISP Mobile Node, LISP-MN) was presented. We analyze LISP-MN and show that it needs double mapping lookups in all LISP gateways, leads to triangle routing under some conditions, and requires double encapsulation. We propose gradual improvements to LISP-MN that avoid these drawbacks under many conditions.

  @inproceedings{info3-inproceedings-2010-381, abstract = {The Locator/Identifier Separation Protocol (LISP) is a new routing architecture for the Internet that separates local and global routing. It offers more flexibility to edge networks and has the potential to reduce the growths of the BGP routing tables. Recently, a concept for mobility in LISP (LISP Mobile Node, LISP-MN) was presented. We analyze LISP-MN and show that it needs double mapping lookups in all LISP gateways, leads to triangle routing under some conditions, and requires double encapsulation. We propose gradual improvements to LISP-MN that avoid these drawbacks under many conditions.}, address = {Amsterdam, The Netherlands}, author = {Menth, Michael and Klein, Dominik and Hartmann, Matthias}, booktitle = {22nd International Teletraffic Congress (ITC)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Improvements to LISP Mobile Node}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-381 %A Menth, Michael %A Klein, Dominik %A Hartmann, Matthias %B 22nd International Teletraffic Congress (ITC) %C Amsterdam, The Netherlands %D 2010 %T Improvements to LISP Mobile Node %X The Locator/Identifier Separation Protocol (LISP) is a new routing architecture for the Internet that separates local and global routing. It offers more flexibility to edge networks and has the potential to reduce the growths of the BGP routing tables. Recently, a concept for mobility in LISP (LISP Mobile Node, LISP-MN) was presented. We analyze LISP-MN and show that it needs double mapping lookups in all LISP gateways, leads to triangle routing under some conditions, and requires double encapsulation. We propose gradual improvements to LISP-MN that avoid these drawbacks under many conditions.
• Optimized IP-Based vs. Explicit Paths for One-to-One Backup in MPLS Fast Reroute. Pióro, Michał; Tomaszewski, Artur; Żukowski, Cezary; Hock, David; Hartmann, Matthias; Menth, Michael. In 14th International Telecommunications Network Strategy and Planning Symposium (NETWORKS 2010), Best Paper Award. Warsaw, Poland, 2010.
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  Primary and backup paths in MPLS fast reroute (FRR) may be established as shortest paths according to the administrative link costs of the IP control plane, or as explicitly calculated arbitrary paths. In both cases, the path layout can be optimized so that the maximum link utilization for a set of considered failure scenarios is minimized. In this paper, we propose a linear program for the optimization of the path layout for explicitly calculated paths, which can either produce single paths and route entire traffic along those paths, or generate multiple paths and spread the traffic among those paths providing load balancing. We compare the resulting lowest maximum link utilization in both cases with the lowest maximum link utilization that can be obtained by optimizing unique IP-based paths. Our results quantify the gain in resource efficiency usage provided by optimized explicit multiple paths or explicit single paths as compared to optimized IP-based paths.

  @inproceedings{info3-inproceedings-2010-389, abstract = {Primary and backup paths in MPLS fast reroute (FRR) may be established as shortest paths according to the administrative link costs of the IP control plane, or as explicitly calculated arbitrary paths. In both cases, the path layout can be optimized so that the maximum link utilization for a set of considered failure scenarios is minimized. In this paper, we propose a linear program for the optimization of the path layout for explicitly calculated paths, which can either produce single paths and route entire traffic along those paths, or generate multiple paths and spread the traffic among those paths providing load balancing. We compare the resulting lowest maximum link utilization in both cases with the lowest maximum link utilization that can be obtained by optimizing unique IP-based paths. Our results quantify the gain in resource efficiency usage provided by optimized explicit multiple paths or explicit single paths as compared to optimized IP-based paths.}, address = {Warsaw, Poland}, author = {Pióro, Michał and Tomaszewski, Artur and Żukowski, Cezary and Hock, David and Hartmann, Matthias and Menth, Michael}, booktitle = {14th International Telecommunications Network Strategy and Planning Symposium (NETWORKS 2010), Best Paper Award}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Optimized IP-Based vs. Explicit Paths for One-to-One Backup in MPLS Fast Reroute}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-389 %A Pióro, Michał %A Tomaszewski, Artur %A Żukowski, Cezary %A Hock, David %A Hartmann, Matthias %A Menth, Michael %B 14th International Telecommunications Network Strategy and Planning Symposium (NETWORKS 2010), Best Paper Award %C Warsaw, Poland %D 2010 %T Optimized IP-Based vs. Explicit Paths for One-to-One Backup in MPLS Fast Reroute %X Primary and backup paths in MPLS fast reroute (FRR) may be established as shortest paths according to the administrative link costs of the IP control plane, or as explicitly calculated arbitrary paths. In both cases, the path layout can be optimized so that the maximum link utilization for a set of considered failure scenarios is minimized. In this paper, we propose a linear program for the optimization of the path layout for explicitly calculated paths, which can either produce single paths and route entire traffic along those paths, or generate multiple paths and spread the traffic among those paths providing load balancing. We compare the resulting lowest maximum link utilization in both cases with the lowest maximum link utilization that can be obtained by optimizing unique IP-based paths. Our results quantify the gain in resource efficiency usage provided by optimized explicit multiple paths or explicit single paths as compared to optimized IP-based paths.
• Overlay Connection Usage in BitTorrent Swarms. Oechsner, Simon; Lehrieder, Frank; Staehle, Dirk. In 3rd Workshop on Economic Traffic Management. Collocated with 22nd International Teletraffic Congress (ITC 22), Amsterdam, Netherlands, 2010.
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  The amount of peer-to-peer (P2P) traffic and its inefficient utilization of network resources make it a high priority for traffic management. Due to the distributed nature of P2P overlays, a promising approach for a management scheme is to change the client behavior and its utilization of overlay connections. However, from the viewpoint of a client, there are different categories of overlay connections. In this paper, we discern between these different types of overlay connections in BitTorrent, the currently most popular P2P file-sharing application. A simulation study of BitTorrent and a video-streaming derivate called Tribler provides insights into the usage of these types of connections for data exchange. Thus, traffic management based on client behavior can be optimized by efficiently targeting connections which carry the most traffic. We also show the implications of these results for locality-awareness mechanisms such as Biased Neighbor Selection and Biased Unchoking.

  @inproceedings{info3-inproceedings-2010-386, abstract = {The amount of peer-to-peer (P2P) traffic and its inefficient utilization of network resources make it a high priority for traffic management. Due to the distributed nature of P2P overlays, a promising approach for a management scheme is to change the client behavior and its utilization of overlay connections. However, from the viewpoint of a client, there are different categories of overlay connections. In this paper, we discern between these different types of overlay connections in BitTorrent, the currently most popular P2P file-sharing application. A simulation study of BitTorrent and a video-streaming derivate called Tribler provides insights into the usage of these types of connections for data exchange. Thus, traffic management based on client behavior can be optimized by efficiently targeting connections which carry the most traffic. We also show the implications of these results for locality-awareness mechanisms such as Biased Neighbor Selection and Biased Unchoking.}, address = {Collocated with 22nd International Teletraffic Congress (ITC 22), Amsterdam, Netherlands}, author = {Oechsner, Simon and Lehrieder, Frank and Staehle, Dirk}, booktitle = {3rd Workshop on Economic Traffic Management}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Overlay Connection Usage in BitTorrent Swarms}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-386 %A Oechsner, Simon %A Lehrieder, Frank %A Staehle, Dirk %B 3rd Workshop on Economic Traffic Management %C Collocated with 22nd International Teletraffic Congress (ITC 22), Amsterdam, Netherlands %D 2010 %T Overlay Connection Usage in BitTorrent Swarms %X The amount of peer-to-peer (P2P) traffic and its inefficient utilization of network resources make it a high priority for traffic management. Due to the distributed nature of P2P overlays, a promising approach for a management scheme is to change the client behavior and its utilization of overlay connections. However, from the viewpoint of a client, there are different categories of overlay connections. In this paper, we discern between these different types of overlay connections in BitTorrent, the currently most popular P2P file-sharing application. A simulation study of BitTorrent and a video-streaming derivate called Tribler provides insights into the usage of these types of connections for data exchange. Thus, traffic management based on client behavior can be optimized by efficiently targeting connections which carry the most traffic. We also show the implications of these results for locality-awareness mechanisms such as Biased Neighbor Selection and Biased Unchoking.
• German-Lab Experimental Facility. Schwerdel, Dennis; Günther, Daniel; Henjes, Robert; Reuther, Bernd; Müller, Paul. In 3rd Future Internet Symposium 2010. Berlin, Germany, 2010.
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  The G-Lab project aims to investigate concepts and technologies for future networks in a practical manner. Thus G-Lab consists of two major fields of activities: research studies of future network components and the design and setup of experimental facilities. Both is controlled by the same community to ensure, that the experimental facility fits to the demand of researchers. Researchers gain access to virtualized resources or may gain exclusive access to resource if necessary.We present the current setup of the experimental facility, describing the available hardware, management of the platform, the utilization of the Planet-Lab software and the user management.

  @inproceedings{info3-inproceedings-2010-396, abstract = {The G-Lab project aims to investigate concepts and technologies for future networks in a practical manner. Thus G-Lab consists of two major fields of activities: research studies of future network components and the design and setup of experimental facilities. Both is controlled by the same community to ensure, that the experimental facility fits to the demand of researchers. Researchers gain access to virtualized resources or may gain exclusive access to resource if necessary.We present the current setup of the experimental facility, describing the available hardware, management of the platform, the utilization of the Planet-Lab software and the user management.}, address = {Berlin, Germany}, author = {Schwerdel, Dennis and Günther, Daniel and Henjes, Robert and Reuther, Bernd and Müller, Paul}, booktitle = {3rd Future Internet Symposium 2010}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {German-Lab Experimental Facility}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-396 %A Schwerdel, Dennis %A Günther, Daniel %A Henjes, Robert %A Reuther, Bernd %A Müller, Paul %B 3rd Future Internet Symposium 2010 %C Berlin, Germany %D 2010 %T German-Lab Experimental Facility %X The G-Lab project aims to investigate concepts and technologies for future networks in a practical manner. Thus G-Lab consists of two major fields of activities: research studies of future network components and the design and setup of experimental facilities. Both is controlled by the same community to ensure, that the experimental facility fits to the demand of researchers. Researchers gain access to virtualized resources or may gain exclusive access to resource if necessary.We present the current setup of the experimental facility, describing the available hardware, management of the platform, the utilization of the Planet-Lab software and the user management.
• BGP-based Locality Promotion for P2P Applications. Racz, Peter; Oechsner, Simon; Lehrieder, Frank. In International Conference on Computer Communication Networks (ICCCN) 2010. Zurich, Switzerland, 2010.
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  P2P applications attract a lot of users and generate the dominant portion of the overall traffic in the Internet today. On the one hand, this large amount of traffic results in high operational costs for ISPs, mainly because of expensive interdomain connections. On the other hand, the performance of P2P applications is constricted by suboptimal peer selection or by bandwidth limitations of ISPs. To overcome these problems, the collaboration of P2P applications and ISPs is desirable, where locality promotion is one of the possible approaches. In this paper, we propose a locality promotion mechanism based on BGP routing information of an ISP and show by simulations that it can reduce inter-domain traffic, prefers shorter connections and peering links over transit links while P2P applications can achieve a better performance as well.

  @inproceedings{info3-inproceedings-2010-377, abstract = {P2P applications attract a lot of users and generate the dominant portion of the overall traffic in the Internet today. On the one hand, this large amount of traffic results in high operational costs for ISPs, mainly because of expensive interdomain connections. On the other hand, the performance of P2P applications is constricted by suboptimal peer selection or by bandwidth limitations of ISPs. To overcome these problems, the collaboration of P2P applications and ISPs is desirable, where locality promotion is one of the possible approaches. In this paper, we propose a locality promotion mechanism based on BGP routing information of an ISP and show by simulations that it can reduce inter-domain traffic, prefers shorter connections and peering links over transit links while P2P applications can achieve a better performance as well.}, address = {Zurich, Switzerland}, author = {Racz, Peter and Oechsner, Simon and Lehrieder, Frank}, booktitle = {International Conference on Computer Communication Networks (ICCCN) 2010}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {BGP-based Locality Promotion for P2P Applications}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-377 %A Racz, Peter %A Oechsner, Simon %A Lehrieder, Frank %B International Conference on Computer Communication Networks (ICCCN) 2010 %C Zurich, Switzerland %D 2010 %T BGP-based Locality Promotion for P2P Applications %X P2P applications attract a lot of users and generate the dominant portion of the overall traffic in the Internet today. On the one hand, this large amount of traffic results in high operational costs for ISPs, mainly because of expensive interdomain connections. On the other hand, the performance of P2P applications is constricted by suboptimal peer selection or by bandwidth limitations of ISPs. To overcome these problems, the collaboration of P2P applications and ISPs is desirable, where locality promotion is one of the possible approaches. In this paper, we propose a locality promotion mechanism based on BGP routing information of an ISP and show by simulations that it can reduce inter-domain traffic, prefers shorter connections and peering links over transit links while P2P applications can achieve a better performance as well.
• YouTube QoE-Aware Gateway Selection in Future Wireless Networks. Wamser, Florian; Staehle, Barbara; Pries, Rastin; Stezenbach, David; Deschner, Sebastian; Staehle, Dirk. In EuroView2010. Würzburg, Germany, 2010.
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  @inproceedings{info3-inproceedings-2010-406, address = {Würzburg, Germany}, author = {Wamser, Florian and Staehle, Barbara and Pries, Rastin and Stezenbach, David and Deschner, Sebastian and Staehle, Dirk}, booktitle = {EuroView2010}, keywords = {demobenefit}, month = {08}, title = {YouTube QoE-Aware Gateway Selection in Future Wireless Networks}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-406 %A Wamser, Florian %A Staehle, Barbara %A Pries, Rastin %A Stezenbach, David %A Deschner, Sebastian %A Staehle, Dirk %B EuroView2010 %C Würzburg, Germany %D 2010 %T YouTube QoE-Aware Gateway Selection in Future Wireless Networks
• The Impact of Caching on BitTorrent-like Peer-to-peer Systems. Lehrieder, Frank; Dán, György; Hoßfeld, Tobias; Oechsner, Simon; Singeorzan, Vlad. In 10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010. Best Paper Award, Delft, the Netherlands, 2010.
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  Peer-to-peer file-sharing systems are responsible for a significant share of the traffic between Internet service providers (ISPs) in the Internet. In order to decrease their peer-to-peer related transit traffic costs, many ISPs have deployed caches for peer-to-peer traffic in recent years. We consider how the different types of peer-to-peer caches - caches already available on the market and caches expected to become available in the future - can possibly affect the amount of inter-ISP traffic. We develop a fluid model that captures the effects of the caches on the system dynamics of peer-to-peer networks, and show that caches can have adverse effects on the system dynamics depending on the system parameters. We combine the fluid model with a simple model of inter-ISP traffic and show that the impact of caches cannot be accurately assessed without considering the effects of the caches on the system dynamics. We identify scenarios when caching actually leads to increased transit traffic. Our analytical results are supported by extensive simulations and experiments with real BitTorrent clients.

  @inproceedings{info3-inproceedings-2010-387, abstract = {Peer-to-peer file-sharing systems are responsible for a significant share of the traffic between Internet service providers (ISPs) in the Internet. In order to decrease their peer-to-peer related transit traffic costs, many ISPs have deployed caches for peer-to-peer traffic in recent years. We consider how the different types of peer-to-peer caches - caches already available on the market and caches expected to become available in the future - can possibly affect the amount of inter-ISP traffic. We develop a fluid model that captures the effects of the caches on the system dynamics of peer-to-peer networks, and show that caches can have adverse effects on the system dynamics depending on the system parameters. We combine the fluid model with a simple model of inter-ISP traffic and show that the impact of caches cannot be accurately assessed without considering the effects of the caches on the system dynamics. We identify scenarios when caching actually leads to increased transit traffic. Our analytical results are supported by extensive simulations and experiments with real BitTorrent clients.}, address = {Best Paper Award, Delft, the Netherlands}, author = {Lehrieder, Frank and Dán, György and Hoßfeld, Tobias and Oechsner, Simon and Singeorzan, Vlad}, booktitle = {10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010}, keywords = {ispeer}, month = {08}, title = {The Impact of Caching on BitTorrent-like Peer-to-peer Systems}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-387 %A Lehrieder, Frank %A Dán, György %A Hoßfeld, Tobias %A Oechsner, Simon %A Singeorzan, Vlad %B 10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010 %C Best Paper Award, Delft, the Netherlands %D 2010 %T The Impact of Caching on BitTorrent-like Peer-to-peer Systems %X Peer-to-peer file-sharing systems are responsible for a significant share of the traffic between Internet service providers (ISPs) in the Internet. In order to decrease their peer-to-peer related transit traffic costs, many ISPs have deployed caches for peer-to-peer traffic in recent years. We consider how the different types of peer-to-peer caches - caches already available on the market and caches expected to become available in the future - can possibly affect the amount of inter-ISP traffic. We develop a fluid model that captures the effects of the caches on the system dynamics of peer-to-peer networks, and show that caches can have adverse effects on the system dynamics depending on the system parameters. We combine the fluid model with a simple model of inter-ISP traffic and show that the impact of caches cannot be accurately assessed without considering the effects of the caches on the system dynamics. We identify scenarios when caching actually leads to increased transit traffic. Our analytical results are supported by extensive simulations and experiments with real BitTorrent clients.
• Can P2P-Users Benefit from Locality-Awareness?. Lehrieder, Frank; Oechsner, Simon; Hoßfeld, Tobias; Despotovic, Zoran; Kellerer, Wolfgang; Michel, Maximilian. In 10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010. Delft, the Netherlands, 2010.
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  Locality-awareness is considered as a promising approach to increase the efficiency of content distribution by peer-to-peer (P2P) networks, e.g., BitTorrent. It is intended to reduce the inter-domain traffic which is costly for Internet service providers (ISPs) and simultaneously increase the performance from the viewpoint of the P2P users, i.e, shorten download times. This win-win situation should be achieved by a preferred exchange of information between peers which are located closely to each other in the underlying network topology. A set of studies shows that these approaches can lead to a win-win situation under certain conditions, and to a win-no lose situation in most cases. However, the scenarios used assume mostly homogeneous peer distributions and that all peers have the same access speed. This is not the case in practice according to several measurement studies. Therefore, we extend previous work in this paper by studying scenarios with real-life, skewed peer distributions and heterogeneous access bandwidths of peers. We show that even a win-no lose situation is difficult to achieve under those conditions and that the actual impact for a specific peer depends heavily on the used locality-aware peer selection and the concrete scenario. Therefore, we conclude that current proposals need to be refined so that users of P2P networks can be sure that they also benefit from their use. Otherwise, a broad acceptance of the concept of locality-awareness in the user community of P2P networks will not take place.

  @inproceedings{info3-inproceedings-2010-388, abstract = {Locality-awareness is considered as a promising approach to increase the efficiency of content distribution by peer-to-peer (P2P) networks, e.g., BitTorrent. It is intended to reduce the inter-domain traffic which is costly for Internet service providers (ISPs) and simultaneously increase the performance from the viewpoint of the P2P users, i.e, shorten download times. This win-win situation should be achieved by a preferred exchange of information between peers which are located closely to each other in the underlying network topology. A set of studies shows that these approaches can lead to a win-win situation under certain conditions, and to a win-no lose situation in most cases. However, the scenarios used assume mostly homogeneous peer distributions and that all peers have the same access speed. This is not the case in practice according to several measurement studies. Therefore, we extend previous work in this paper by studying scenarios with real-life, skewed peer distributions and heterogeneous access bandwidths of peers. We show that even a win-no lose situation is difficult to achieve under those conditions and that the actual impact for a specific peer depends heavily on the used locality-aware peer selection and the concrete scenario. Therefore, we conclude that current proposals need to be refined so that users of P2P networks can be sure that they also benefit from their use. Otherwise, a broad acceptance of the concept of locality-awareness in the user community of P2P networks will not take place.}, address = {Delft, the Netherlands}, author = {Lehrieder, Frank and Oechsner, Simon and Hoßfeld, Tobias and Despotovic, Zoran and Kellerer, Wolfgang and Michel, Maximilian}, booktitle = {10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Can P2P-Users Benefit from Locality-Awareness?}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-388 %A Lehrieder, Frank %A Oechsner, Simon %A Hoßfeld, Tobias %A Despotovic, Zoran %A Kellerer, Wolfgang %A Michel, Maximilian %B 10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010 %C Delft, the Netherlands %D 2010 %T Can P2P-Users Benefit from Locality-Awareness? %X Locality-awareness is considered as a promising approach to increase the efficiency of content distribution by peer-to-peer (P2P) networks, e.g., BitTorrent. It is intended to reduce the inter-domain traffic which is costly for Internet service providers (ISPs) and simultaneously increase the performance from the viewpoint of the P2P users, i.e, shorten download times. This win-win situation should be achieved by a preferred exchange of information between peers which are located closely to each other in the underlying network topology. A set of studies shows that these approaches can lead to a win-win situation under certain conditions, and to a win-no lose situation in most cases. However, the scenarios used assume mostly homogeneous peer distributions and that all peers have the same access speed. This is not the case in practice according to several measurement studies. Therefore, we extend previous work in this paper by studying scenarios with real-life, skewed peer distributions and heterogeneous access bandwidths of peers. We show that even a win-no lose situation is difficult to achieve under those conditions and that the actual impact for a specific peer depends heavily on the used locality-aware peer selection and the concrete scenario. Therefore, we conclude that current proposals need to be refined so that users of P2P networks can be sure that they also benefit from their use. Otherwise, a broad acceptance of the concept of locality-awareness in the user community of P2P networks will not take place.
• Tuontu: A Tool for Evaluating the Impact of Wireless Sensor Network Design Alternatives. Staehle, Barbara; Leimbach, Markus; Staehle, Dirk. In 9. GI/ITG KuVS Fachgespräch Sensornetze. Würzburg, Germany, 2010.
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  With an increasing wireless sensor network (WSN) application complexity, more alternatives for the WSN design arose. This complexity is also the reason why it is difficult to asses how and at which price in terms of money or decreased quality of service, design alternatives increase the system performance. In this work we therefore introduce a concept for quickly answering likewise questions, namely the task-based resource consumption modeling. It is the heart of the framework Tuontu which allows to easily estimate if an application is feasible in a given WSN deployment and which performance is to expect.

  @inproceedings{info3-inproceedings-2010-397, abstract = {With an increasing wireless sensor network (WSN) application complexity, more alternatives for the WSN design arose. This complexity is also the reason why it is difficult to asses how and at which price in terms of money or decreased quality of service, design alternatives increase the system performance. In this work we therefore introduce a concept for quickly answering likewise questions, namely the task-based resource consumption modeling. It is the heart of the framework Tuontu which allows to easily estimate if an application is feasible in a given WSN deployment and which performance is to expect.}, address = {Würzburg, Germany}, author = {Staehle, Barbara and Leimbach, Markus and Staehle, Dirk}, booktitle = {9. GI/ITG KuVS Fachgespräch Sensornetze}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Tuontu: A Tool for Evaluating the Impact of Wireless Sensor Network Design Alternatives}, year = 2010 }

  %0 Conference Paper %1 info3-inproceedings-2010-397 %A Staehle, Barbara %A Leimbach, Markus %A Staehle, Dirk %B 9. GI/ITG KuVS Fachgespräch Sensornetze %C Würzburg, Germany %D 2010 %T Tuontu: A Tool for Evaluating the Impact of Wireless Sensor Network Design Alternatives %X With an increasing wireless sensor network (WSN) application complexity, more alternatives for the WSN design arose. This complexity is also the reason why it is difficult to asses how and at which price in terms of money or decreased quality of service, design alternatives increase the system performance. In this work we therefore introduce a concept for quickly answering likewise questions, namely the task-based resource consumption modeling. It is the heart of the framework Tuontu which allows to easily estimate if an application is feasible in a given WSN deployment and which performance is to expect.

• Optimizing the Association Procedure for Low-Power 802.15.4 Nonbeacon Sensor Networks. Staehle, Barbara. In Networking 2009. Aachen, Germany, 2009.
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  Building wireless sensor networks based on the IEEE 802.15.4 standard is an interesting option, as the standard enables low-power, low data rate wireless communication. Many authors analyzed and optimized the operational phase of such networks. In contrast, the initial phase, containing the 802.15.4 association procedure, has mostly been neglected. In this paper, we therefore propose four optimization possibilities for the association procedure of a nonbeacon-enabled sensor network. Our results show that significant performance improvements in terms of association probability, speed, and energy consumptions can be achieved.

  @inproceedings{info3-inproceedings-2009-339, abstract = {Building wireless sensor networks based on the IEEE 802.15.4 standard is an interesting option, as the standard enables low-power, low data rate wireless communication. Many authors analyzed and optimized the operational phase of such networks. In contrast, the initial phase, containing the 802.15.4 association procedure, has mostly been neglected. In this paper, we therefore propose four optimization possibilities for the association procedure of a nonbeacon-enabled sensor network. Our results show that significant performance improvements in terms of association probability, speed, and energy consumptions can be achieved.}, address = {Aachen, Germany}, author = {Staehle, Barbara}, booktitle = {Networking 2009}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Optimizing the Association Procedure for Low-Power 802.15.4 Nonbeacon Sensor Networks}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-339 %A Staehle, Barbara %B Networking 2009 %C Aachen, Germany %D 2009 %T Optimizing the Association Procedure for Low-Power 802.15.4 Nonbeacon Sensor Networks %X Building wireless sensor networks based on the IEEE 802.15.4 standard is an interesting option, as the standard enables low-power, low data rate wireless communication. Many authors analyzed and optimized the operational phase of such networks. In contrast, the initial phase, containing the 802.15.4 association procedure, has mostly been neglected. In this paper, we therefore propose four optimization possibilities for the association procedure of a nonbeacon-enabled sensor network. Our results show that significant performance improvements in terms of association probability, speed, and energy consumptions can be achieved.
• A Generic Algorithm for CAPEX-Aware Multi-Layer Network Design. Duelli, Michael; Weber, Eduard; Menth, Michael. In 10. ITG-Fachtagung Photonische Netze, pp. 167–174. Leipzig, Germany, 2009.
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  Capital expenditure (CAPEX), i.e. equipment cost, is a decisive criterion for the design of a new network infrastructure. The design of efficient transport networks requires the interconnection of multiple technologies which form separate layers with their own networking view and routing. This leads to the notion of multi-layer networks. CAPEX-aware design of such networks requires algorithms which propose multi-layer hardware configurations that are able to carry a given set of traffic demands at minimal CAPEX. We present a generic algorithm for CAPEX-aware multi-layer network design as well as a computationally viable implementation and perform evaluations on realistic network topologies. The underlying CAPEX and multi-layer technology models are explained in detail.

  @inproceedings{info3-inproceedings-2009-343, abstract = {Capital expenditure (CAPEX), i.e. equipment cost, is a decisive criterion for the design of a new network infrastructure. The design of efficient transport networks requires the interconnection of multiple technologies which form separate layers with their own networking view and routing. This leads to the notion of multi-layer networks. CAPEX-aware design of such networks requires algorithms which propose multi-layer hardware configurations that are able to carry a given set of traffic demands at minimal CAPEX. We present a generic algorithm for CAPEX-aware multi-layer network design as well as a computationally viable implementation and perform evaluations on realistic network topologies. The underlying CAPEX and multi-layer technology models are explained in detail.}, address = {Leipzig, Germany}, author = {Duelli, Michael and Weber, Eduard and Menth, Michael}, booktitle = {10. ITG-Fachtagung Photonische Netze}, keywords = {100get}, month = {05}, pages = {167–174}, title = {A Generic Algorithm for CAPEX-Aware Multi-Layer Network Design}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-343 %A Duelli, Michael %A Weber, Eduard %A Menth, Michael %B 10. ITG-Fachtagung Photonische Netze %C Leipzig, Germany %D 2009 %P 167--174 %T A Generic Algorithm for CAPEX-Aware Multi-Layer Network Design %X Capital expenditure (CAPEX), i.e. equipment cost, is a decisive criterion for the design of a new network infrastructure. The design of efficient transport networks requires the interconnection of multiple technologies which form separate layers with their own networking view and routing. This leads to the notion of multi-layer networks. CAPEX-aware design of such networks requires algorithms which propose multi-layer hardware configurations that are able to carry a given set of traffic demands at minimal CAPEX. We present a generic algorithm for CAPEX-aware multi-layer network design as well as a computationally viable implementation and perform evaluations on realistic network topologies. The underlying CAPEX and multi-layer technology models are explained in detail.
• Performance Evaluation of a Distributed Lookup System for a Virtual Database Server. Oechsner, Simon; Hoßfeld, Tobias; Tran-Gia, Phuoc. In 20th ITC Specialist Seminar. Hoi An, Vietnam, 2009.
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  Services offered today rely on large amounts of data that can be accessed fast and reliably. One technical solution providing both acceptable speed and high reliability are distributed databases, which can be accessed from an application as one virtual database server. The virtualization here hides complexity introduced by distributing the service to a set of machines. In this paper, we will present a DHT-based architecture implementing a lookup layer for such a database, which preserves important features such as self-organization from its DHT roots, but still offers a good performance for time-critical applications. Additionally, first anaytical results are given, which show some of the basic mechanisms at work in such systems.

  @inproceedings{info3-inproceedings-2009-344, abstract = {Services offered today rely on large amounts of data that can be accessed fast and reliably. One technical solution providing both acceptable speed and high reliability are distributed databases, which can be accessed from an application as one virtual database server. The virtualization here hides complexity introduced by distributing the service to a set of machines. In this paper, we will present a DHT-based architecture implementing a lookup layer for such a database, which preserves important features such as self-organization from its DHT roots, but still offers a good performance for time-critical applications. Additionally, first anaytical results are given, which show some of the basic mechanisms at work in such systems.}, address = {Hoi An, Vietnam}, author = {Oechsner, Simon and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {20th ITC Specialist Seminar}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Performance Evaluation of a Distributed Lookup System for a Virtual Database Server}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-344 %A Oechsner, Simon %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B 20th ITC Specialist Seminar %C Hoi An, Vietnam %D 2009 %T Performance Evaluation of a Distributed Lookup System for a Virtual Database Server %X Services offered today rely on large amounts of data that can be accessed fast and reliably. One technical solution providing both acceptable speed and high reliability are distributed databases, which can be accessed from an application as one virtual database server. The virtualization here hides complexity introduced by distributing the service to a set of machines. In this paper, we will present a DHT-based architecture implementing a lookup layer for such a database, which preserves important features such as self-organization from its DHT roots, but still offers a good performance for time-critical applications. Additionally, first anaytical results are given, which show some of the basic mechanisms at work in such systems.
• Performance Study of a Video Application over Multi-Hop Wireless Networks with Statistic-Based Routing. Klein, Alexander; Klaue, Jirka. In Networking 2009, p. 7. Aix-La-Chapelle, Germany, 2009.
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  We present a framework for performance evaluation and optimization of video applications in mobile multi hop networks. We focus on the perceived video quality depending on the simulated mobility model, traffic pattern, retransmission strategy, and the configuration of the routing protocol. Moreover, the functionality of the framework is demonstrated by evaluating the performance of a video surveillance application with multiple mobile sources and sinks. The application is designed for exchanging multimedia content, e.g. audio and video streams, in wireless networks where all nodes are highly mobile.

  @inproceedings{info3-inproceedings-2009-341, abstract = {We present a framework for performance evaluation and optimization of video applications in mobile multi hop networks. We focus on the perceived video quality depending on the simulated mobility model, traffic pattern, retransmission strategy, and the configuration of the routing protocol. Moreover, the functionality of the framework is demonstrated by evaluating the performance of a video surveillance application with multiple mobile sources and sinks. The application is designed for exchanging multimedia content, e.g. audio and video streams, in wireless networks where all nodes are highly mobile.}, address = {Aix-La-Chapelle, Germany}, author = {Klein, Alexander and Klaue, Jirka}, booktitle = {Networking 2009}, keywords = {sys:hidden:inproceedings}, month = {05}, pages = 7, title = {Performance Study of a Video Application over Multi-Hop Wireless Networks with Statistic-Based Routing}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-341 %A Klein, Alexander %A Klaue, Jirka %B Networking 2009 %C Aix-La-Chapelle, Germany %D 2009 %P 7 %T Performance Study of a Video Application over Multi-Hop Wireless Networks with Statistic-Based Routing %X We present a framework for performance evaluation and optimization of video applications in mobile multi hop networks. We focus on the perceived video quality depending on the simulated mobility model, traffic pattern, retransmission strategy, and the configuration of the routing protocol. Moreover, the functionality of the framework is demonstrated by evaluating the performance of a video surveillance application with multiple mobile sources and sinks. The application is designed for exchanging multimedia content, e.g. audio and video streams, in wireless networks where all nodes are highly mobile.
• Service Oriented Network Framework Enabling Global QoS and Network Virtualization. Schlosser, Daniel; Hoßfeld, Tobias. In ITC SS 2009. Hoi An, 2009.
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  Today’s Internet provides access to a large variety of services, which require high data rates and stable data flows for satisfactory service quality. New interactive services have high Quality of Service (QoS) requirements to the network. Packet loss, jitter, delay and effectively available bandwidth are parameters that heavily influence the Quality of Experience (QoE) of a user. The current architecture of the Internet cannot support these QoS requirements on a global scale, as solutions of one Internet Service Provider (ISP) do not necessarily work across borders of ISP domains. In order to provide QoS on a global level, the Internet of the future might offer virtual networks as data delivery services that can guarantee all the requirements of an application or service. We therefore propose a service oriented network framework. Within this framework different virtual network connections with the corresponding pricing schemes that satisfy a given request will be offered to the customer. In this paper we (1) introduce the architecture concept, (2) show how the QoS of a network path can be concluded from QoS description of its parts and (3) perform a measurement study to evaluate a measurement approach, which classifies the QoS of a network connection between two routers based on active measurements performed by the routers themselves.

  @inproceedings{info3-inproceedings-2009-353, abstract = {Today’s Internet provides access to a large variety of services, which require high data rates and stable data flows for satisfactory service quality. New interactive services have high Quality of Service (QoS) requirements to the network. Packet loss, jitter, delay and effectively available bandwidth are parameters that heavily influence the Quality of Experience (QoE) of a user. The current architecture of the Internet cannot support these QoS requirements on a global scale, as solutions of one Internet Service Provider (ISP) do not necessarily work across borders of ISP domains. In order to provide QoS on a global level, the Internet of the future might offer virtual networks as data delivery services that can guarantee all the requirements of an application or service. We therefore propose a service oriented network framework. Within this framework different virtual network connections with the corresponding pricing schemes that satisfy a given request will be offered to the customer. In this paper we (1) introduce the architecture concept, (2) show how the QoS of a network path can be concluded from QoS description of its parts and (3) perform a measurement study to evaluate a measurement approach, which classifies the QoS of a network connection between two routers based on active measurements performed by the routers themselves.}, address = {Hoi An}, author = {Schlosser, Daniel and Hoßfeld, Tobias}, booktitle = {ITC SS 2009}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Service Oriented Network Framework Enabling Global QoS and Network Virtualization}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-353 %A Schlosser, Daniel %A Hoßfeld, Tobias %B ITC SS 2009 %C Hoi An %D 2009 %T Service Oriented Network Framework Enabling Global QoS and Network Virtualization %X Today’s Internet provides access to a large variety of services, which require high data rates and stable data flows for satisfactory service quality. New interactive services have high Quality of Service (QoS) requirements to the network. Packet loss, jitter, delay and effectively available bandwidth are parameters that heavily influence the Quality of Experience (QoE) of a user. The current architecture of the Internet cannot support these QoS requirements on a global scale, as solutions of one Internet Service Provider (ISP) do not necessarily work across borders of ISP domains. In order to provide QoS on a global level, the Internet of the future might offer virtual networks as data delivery services that can guarantee all the requirements of an application or service. We therefore propose a service oriented network framework. Within this framework different virtual network connections with the corresponding pricing schemes that satisfy a given request will be offered to the customer. In this paper we (1) introduce the architecture concept, (2) show how the QoS of a network path can be concluded from QoS description of its parts and (3) perform a measurement study to evaluate a measurement approach, which classifies the QoS of a network connection between two routers based on active measurements performed by the routers themselves.
• Re-sequencing Buffer Occupancy of a Concurrent Multipath Transmission Mechanism for Transport System Virtualization. Tutschku, Kurt; Zinner, Thomas; Nakao, Akihiro; Tran-Gia, Phuoc. In KiVS 2009. Kassel, 2009.
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  From the viewpoint of a methodology, the concept of Net- work Virtualization (NV) extends beyond pure operational issues. In this paper, we will first transfer the concept of location independence of resources, as known in operating systems, to the area of data transport in communication networks. This idea is denoted as transport sys- tem virtualization (TSV). We will outline an example for TSV which uses concurrent multipath (CMP) transmission and discuss an important performance issue of CMP transmission, the re-sequencing buer occupancy probability distribution. The investigation of this probability distribution gives insights in how to select the set of paths when using CMP transmission for transport system virtualization.

  @inproceedings{info3-inproceedings-2009-333, abstract = {From the viewpoint of a methodology, the concept of Net- work Virtualization (NV) extends beyond pure operational issues. In this paper, we will first transfer the concept of location independence of resources, as known in operating systems, to the area of data transport in communication networks. This idea is denoted as transport sys- tem virtualization (TSV). We will outline an example for TSV which uses concurrent multipath (CMP) transmission and discuss an important performance issue of CMP transmission, the re-sequencing buer occupancy probability distribution. The investigation of this probability distribution gives insights in how to select the set of paths when using CMP transmission for transport system virtualization.}, address = {Kassel}, author = {Tutschku, Kurt and Zinner, Thomas and Nakao, Akihiro and Tran-Gia, Phuoc}, booktitle = {KiVS 2009}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Re-sequencing Buffer Occupancy of a Concurrent Multipath Transmission Mechanism for Transport System Virtualization}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-333 %A Tutschku, Kurt %A Zinner, Thomas %A Nakao, Akihiro %A Tran-Gia, Phuoc %B KiVS 2009 %C Kassel %D 2009 %T Re-sequencing Buffer Occupancy of a Concurrent Multipath Transmission Mechanism for Transport System Virtualization %X From the viewpoint of a methodology, the concept of Net- work Virtualization (NV) extends beyond pure operational issues. In this paper, we will first transfer the concept of location independence of resources, as known in operating systems, to the area of data transport in communication networks. This idea is denoted as transport sys- tem virtualization (TSV). We will outline an example for TSV which uses concurrent multipath (CMP) transmission and discuss an important performance issue of CMP transmission, the re-sequencing buer occupancy probability distribution. The investigation of this probability distribution gives insights in how to select the set of paths when using CMP transmission for transport system virtualization.
• Performance Evaluation of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization. Zinner, Thomas; Tutschku, Kurt; Nakao, Akihiro; Tran-Gia, Phuoc. In 20th ITC Specialist Seminar. Hoi An, Viet nam, 2009.
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  @inproceedings{info3-inproceedings-2009-348, address = {Hoi An, Viet nam}, author = {Zinner, Thomas and Tutschku, Kurt and Nakao, Akihiro and Tran-Gia, Phuoc}, booktitle = {20th ITC Specialist Seminar}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Performance Evaluation of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-348 %A Zinner, Thomas %A Tutschku, Kurt %A Nakao, Akihiro %A Tran-Gia, Phuoc %B 20th ITC Specialist Seminar %C Hoi An, Viet nam %D 2009 %T Performance Evaluation of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization
• Impact of Self-Organization in P2P Overlays on Underlay Utilization. Pussep, Konstantin; Oechsner, Simon; Abboud, Osama; Kantor, Miroslaw; Stiller, Burkhard. In The Fourth International Conference on Internet and Web Applications and Services. Venice, Italy, 2009.
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  Peer-to-Peer (P2P) systems gained popularity and are responsible for a large share of today’s Internet traffic. Nevertheless, their dynamic nature and the intended lack of control through central instances make their behavior unpredictable and, therefore, it is difficult to achieve a high level of Quality-of-Service for P2P traffic. Thus, peers are themselves responsible for dealing with these issues by applying so-called self-organization mechanisms to deal with their heterogeneity, unpredictable behavior, and asymmetric resources. This paper discusses and classifies relevant self-organizing aspects of P2P systems, including metrics and mechanisms. Hereby, the key focus is in better understanding on how such self-organizing mechanisms - originally designed to improve the performance of P2P overlays - affect the underlying Internet infrastructure.

  @inproceedings{info3-inproceedings-2009-340, abstract = {Peer-to-Peer (P2P) systems gained popularity and are responsible for a large share of today’s Internet traffic. Nevertheless, their dynamic nature and the intended lack of control through central instances make their behavior unpredictable and, therefore, it is difficult to achieve a high level of Quality-of-Service for P2P traffic. Thus, peers are themselves responsible for dealing with these issues by applying so-called self-organization mechanisms to deal with their heterogeneity, unpredictable behavior, and asymmetric resources. This paper discusses and classifies relevant self-organizing aspects of P2P systems, including metrics and mechanisms. Hereby, the key focus is in better understanding on how such self-organizing mechanisms - originally designed to improve the performance of P2P overlays - affect the underlying Internet infrastructure.}, address = {Venice, Italy}, author = {Pussep, Konstantin and Oechsner, Simon and Abboud, Osama and Kantor, Miroslaw and Stiller, Burkhard}, booktitle = {The Fourth International Conference on Internet and Web Applications and Services}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Impact of Self-Organization in P2P Overlays on Underlay Utilization}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-340 %A Pussep, Konstantin %A Oechsner, Simon %A Abboud, Osama %A Kantor, Miroslaw %A Stiller, Burkhard %B The Fourth International Conference on Internet and Web Applications and Services %C Venice, Italy %D 2009 %T Impact of Self-Organization in P2P Overlays on Underlay Utilization %X Peer-to-Peer (P2P) systems gained popularity and are responsible for a large share of today’s Internet traffic. Nevertheless, their dynamic nature and the intended lack of control through central instances make their behavior unpredictable and, therefore, it is difficult to achieve a high level of Quality-of-Service for P2P traffic. Thus, peers are themselves responsible for dealing with these issues by applying so-called self-organization mechanisms to deal with their heterogeneity, unpredictable behavior, and asymmetric resources. This paper discusses and classifies relevant self-organizing aspects of P2P systems, including metrics and mechanisms. Hereby, the key focus is in better understanding on how such self-organizing mechanisms - originally designed to improve the performance of P2P overlays - affect the underlying Internet infrastructure.
• Impact of Best Effort Frame Bursting in IEEE 802.11 Networks. Pries, Rastin; Staehle, Dirk; Menth, Stefan; Menth, Michael; Tran-Gia, Phuoc. In IEEE VTC Spring 09. Barcelona, Spain, 2009.
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  Wireless LAN strongly prioritizes high priority traffic over low priority best effort traffic. This causes reduced access to the medium for low priority traffic and under some conditions even leads to starvation. To compensate the throughput reduction of low priority traffic, we propose frame bursting in this paper. That means low priority traffic is sent infrequently, but many frames may be sent in a burst. Our simulation results show that the throughput of the low priority best effort traffic class can be significantly increased without disrupting high priority traffic.

  @inproceedings{info3-inproceedings-2009-335, abstract = {Wireless LAN strongly prioritizes high priority traffic over low priority best effort traffic. This causes reduced access to the medium for low priority traffic and under some conditions even leads to starvation. To compensate the throughput reduction of low priority traffic, we propose frame bursting in this paper. That means low priority traffic is sent infrequently, but many frames may be sent in a burst. Our simulation results show that the throughput of the low priority best effort traffic class can be significantly increased without disrupting high priority traffic.}, address = {Barcelona, Spain}, author = {Pries, Rastin and Staehle, Dirk and Menth, Stefan and Menth, Michael and Tran-Gia, Phuoc}, booktitle = {IEEE VTC Spring 09}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Impact of Best Effort Frame Bursting in IEEE 802.11 Networks}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-335 %A Pries, Rastin %A Staehle, Dirk %A Menth, Stefan %A Menth, Michael %A Tran-Gia, Phuoc %B IEEE VTC Spring 09 %C Barcelona, Spain %D 2009 %T Impact of Best Effort Frame Bursting in IEEE 802.11 Networks %X Wireless LAN strongly prioritizes high priority traffic over low priority best effort traffic. This causes reduced access to the medium for low priority traffic and under some conditions even leads to starvation. To compensate the throughput reduction of low priority traffic, we propose frame bursting in this paper. That means low priority traffic is sent infrequently, but many frames may be sent in a burst. Our simulation results show that the throughput of the low priority best effort traffic class can be significantly increased without disrupting high priority traffic.
• Traffic Measurement and Analysis of a Broadband Wireless Internet Access. Pries, Rastin; Wamser, Florian; Staehle, Dirk; Heck, Klaus; Tran-Gia, Phuoc. In IEEE VTC Spring 09. Barcelona, Spain, 2009.
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  The increasing broadband wireless Internet usage and the limited wireless resources require a careful network management and optimization of the wireless Internet Service Providers (ISPs). Unfortunately, those providers often just have statistics about the overall usage and limited knowledge about the detailed application distribution as well as the traffic characteristics. In this paper we present user and traffic characteristics measured at a broadband wireless Internet access. The results show that the applications change quickly but the general characteristics like packet size and TCP/UDP percentage have not changed during the last years.

  @inproceedings{info3-inproceedings-2009-336, abstract = {The increasing broadband wireless Internet usage and the limited wireless resources require a careful network management and optimization of the wireless Internet Service Providers (ISPs). Unfortunately, those providers often just have statistics about the overall usage and limited knowledge about the detailed application distribution as well as the traffic characteristics. In this paper we present user and traffic characteristics measured at a broadband wireless Internet access. The results show that the applications change quickly but the general characteristics like packet size and TCP/UDP percentage have not changed during the last years.}, address = {Barcelona, Spain}, author = {Pries, Rastin and Wamser, Florian and Staehle, Dirk and Heck, Klaus and Tran-Gia, Phuoc}, booktitle = {IEEE VTC Spring 09}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Traffic Measurement and Analysis of a Broadband Wireless Internet Access}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-336 %A Pries, Rastin %A Wamser, Florian %A Staehle, Dirk %A Heck, Klaus %A Tran-Gia, Phuoc %B IEEE VTC Spring 09 %C Barcelona, Spain %D 2009 %T Traffic Measurement and Analysis of a Broadband Wireless Internet Access %X The increasing broadband wireless Internet usage and the limited wireless resources require a careful network management and optimization of the wireless Internet Service Providers (ISPs). Unfortunately, those providers often just have statistics about the overall usage and limited knowledge about the detailed application distribution as well as the traffic characteristics. In this paper we present user and traffic characteristics measured at a broadband wireless Internet access. The results show that the applications change quickly but the general characteristics like packet size and TCP/UDP percentage have not changed during the last years.
• PCN-Based Flow Termination with Multiple Bottleneck Links. Lehrieder, Frank; Menth, Michael. In IEEE International Conference on Communications (ICC). Dresden, Germany, 2009.
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  From the viewpoint of communication networks Network Virtualization (NV) extends beyond pure operational issues and addresses many of the impasses of the current Internet. The idea of Transport Virtualization (TV) progresses the capabilities of NV and enables the independence from a specific network transport resource. The independence is achieved by pooling multiple transport resources and selecting the best resources for exclusive or concurrent use. However, the application and selection of concurrent paths is rather complex and introduces inevitable packet re-ordering due to different stochastic delay characteristics on the used paths. Packets arriving at the destination out-of-order have to be stored in a re-sequencing buffer before reassembled packets are forwarded to the application. Therefore we perform an analysis of the fundamental behaviors and factors for packet re-ordering in concurrent multipath transmissions. This analysis applies analytical and simulative techniques which are used to compute the buffer occupancy probability distribution.

  @inproceedings{info3-inproceedings-2009-337, abstract = {From the viewpoint of communication networks Network Virtualization (NV) extends beyond pure operational issues and addresses many of the impasses of the current Internet. The idea of Transport Virtualization (TV) progresses the capabilities of NV and enables the independence from a specific network transport resource. The independence is achieved by pooling multiple transport resources and selecting the best resources for exclusive or concurrent use. However, the application and selection of concurrent paths is rather complex and introduces inevitable packet re-ordering due to different stochastic delay characteristics on the used paths. Packets arriving at the destination out-of-order have to be stored in a re-sequencing buffer before reassembled packets are forwarded to the application. Therefore we perform an analysis of the fundamental behaviors and factors for packet re-ordering in concurrent multipath transmissions. This analysis applies analytical and simulative techniques which are used to compute the buffer occupancy probability distribution.}, address = {Dresden, Germany}, author = {Lehrieder, Frank and Menth, Michael}, booktitle = {IEEE International Conference on Communications (ICC)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {PCN-Based Flow Termination with Multiple Bottleneck Links}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-337 %A Lehrieder, Frank %A Menth, Michael %B IEEE International Conference on Communications (ICC) %C Dresden, Germany %D 2009 %T PCN-Based Flow Termination with Multiple Bottleneck Links %X From the viewpoint of communication networks Network Virtualization (NV) extends beyond pure operational issues and addresses many of the impasses of the current Internet. The idea of Transport Virtualization (TV) progresses the capabilities of NV and enables the independence from a specific network transport resource. The independence is achieved by pooling multiple transport resources and selecting the best resources for exclusive or concurrent use. However, the application and selection of concurrent paths is rather complex and introduces inevitable packet re-ordering due to different stochastic delay characteristics on the used paths. Packets arriving at the destination out-of-order have to be stored in a re-sequencing buffer before reassembled packets are forwarded to the application. Therefore we perform an analysis of the fundamental behaviors and factors for packet re-ordering in concurrent multipath transmissions. This analysis applies analytical and simulative techniques which are used to compute the buffer occupancy probability distribution.
• Network Virtualization: Implementation Steps Towards the Future Internet. Tutschku, Kurt; Zinner, Thomas; Nakao, Akihiro; Tran-Gia, Phuoc. In KiVS 2009. Kassel, 2009.
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  In this paper we will investigate why and how Network Virtualization (NV) can overcome the shortfalls of the current system and how it paves the way for the Future Internet. Therefore, we will first discuss some major deficiencies and achievements of today’s Internet. Afterwards, we identify three major building blocks of NV: a) the use of application-specific routing overlays, b) the safe consolidation of resources by OS virtualization on a generic infrastructure, and c) the exploitation of the network diversity for performance enhancements and for new business models, such as the provisioning of intermediate nodes or path oracles. Subsequently, we discuss an implementation scheme for network virtualization or routing overlays based on one-hop source routers (OSRs). The capabilities of the combination of NV and OSRs are demonstrated by a concurrent multipath transmission (CMP) mechanism (also known as stripping) for obtaining high throughput transmission pipes. The suggested stripping mechanism constitutes a first instance of a refinement of the concept of NV, the idea of transport system virtualization.

  @inproceedings{info3-inproceedings-2009-330, abstract = {In this paper we will investigate why and how Network Virtualization (NV) can overcome the shortfalls of the current system and how it paves the way for the Future Internet. Therefore, we will first discuss some major deficiencies and achievements of today’s Internet. Afterwards, we identify three major building blocks of NV: a) the use of application-specific routing overlays, b) the safe consolidation of resources by OS virtualization on a generic infrastructure, and c) the exploitation of the network diversity for performance enhancements and for new business models, such as the provisioning of intermediate nodes or path oracles. Subsequently, we discuss an implementation scheme for network virtualization or routing overlays based on one-hop source routers (OSRs). The capabilities of the combination of NV and OSRs are demonstrated by a concurrent multipath transmission (CMP) mechanism (also known as stripping) for obtaining high throughput transmission pipes. The suggested stripping mechanism constitutes a first instance of a refinement of the concept of NV, the idea of transport system virtualization.}, address = {Kassel}, author = {Tutschku, Kurt and Zinner, Thomas and Nakao, Akihiro and Tran-Gia, Phuoc}, booktitle = {KiVS 2009}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Network Virtualization: Implementation Steps Towards the Future Internet}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-330 %A Tutschku, Kurt %A Zinner, Thomas %A Nakao, Akihiro %A Tran-Gia, Phuoc %B KiVS 2009 %C Kassel %D 2009 %T Network Virtualization: Implementation Steps Towards the Future Internet %X In this paper we will investigate why and how Network Virtualization (NV) can overcome the shortfalls of the current system and how it paves the way for the Future Internet. Therefore, we will first discuss some major deficiencies and achievements of today’s Internet. Afterwards, we identify three major building blocks of NV: a) the use of application-specific routing overlays, b) the safe consolidation of resources by OS virtualization on a generic infrastructure, and c) the exploitation of the network diversity for performance enhancements and for new business models, such as the provisioning of intermediate nodes or path oracles. Subsequently, we discuss an implementation scheme for network virtualization or routing overlays based on one-hop source routers (OSRs). The capabilities of the combination of NV and OSRs are demonstrated by a concurrent multipath transmission (CMP) mechanism (also known as stripping) for obtaining high throughput transmission pipes. The suggested stripping mechanism constitutes a first instance of a refinement of the concept of NV, the idea of transport system virtualization.
• Towards Quality of Experience-based Reputation Models for Future Web Service Provisioning. Ciszkowski, Tomasz; Mazurczyk, Wojciech; Kotulski, Zbigniew; Hoßfeld, Tobias; Fiedler, Markus; Collange, Denis. In Future Internet Architectures: New Trends in Service Architectures (2nd Euro-NF Workshop). Santander, Spain, 2009.
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  This paper concerns the applicability of reputations systems for assessing Quality of Experience (QoE) for web services in Future Internet. Reputation systems provide mechanisms to manage subjective opinions in societies and yield general scoring of a particular behavior. Thus, they are likely to become an important ingredient of Future Internet. Parameters being under evaluation by reputation system may vary greatly and, particularly, may be chosen to assess the users’ satisfaction with (composite) web services. Currently, this satisfaction is usually expressed with QoE, which represents subjective users’ opinions. The goal is to predict users’ satisfaction based on reputation values. This may be beneficial for service providers in terms of checking the fulfillment of SLAs, for retaining QoE on the satisfaction level for other users sharing the same network or service resources, and for providing the users with indications which resource to choose in order to maximize its experience.

  @inproceedings{info3-inproceedings-2009-354, abstract = {This paper concerns the applicability of reputations systems for assessing Quality of Experience (QoE) for web services in Future Internet. Reputation systems provide mechanisms to manage subjective opinions in societies and yield general scoring of a particular behavior. Thus, they are likely to become an important ingredient of Future Internet. Parameters being under evaluation by reputation system may vary greatly and, particularly, may be chosen to assess the users’ satisfaction with (composite) web services. Currently, this satisfaction is usually expressed with QoE, which represents subjective users’ opinions. The goal is to predict users’ satisfaction based on reputation values. This may be beneficial for service providers in terms of checking the fulfillment of SLAs, for retaining QoE on the satisfaction level for other users sharing the same network or service resources, and for providing the users with indications which resource to choose in order to maximize its experience.}, address = {Santander, Spain}, author = {Ciszkowski, Tomasz and Mazurczyk, Wojciech and Kotulski, Zbigniew and Hoßfeld, Tobias and Fiedler, Markus and Collange, Denis}, booktitle = {Future Internet Architectures: New Trends in Service Architectures (2nd Euro-NF Workshop)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Towards Quality of Experience-based Reputation Models for Future Web Service Provisioning}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-354 %A Ciszkowski, Tomasz %A Mazurczyk, Wojciech %A Kotulski, Zbigniew %A Hoßfeld, Tobias %A Fiedler, Markus %A Collange, Denis %B Future Internet Architectures: New Trends in Service Architectures (2nd Euro-NF Workshop) %C Santander, Spain %D 2009 %T Towards Quality of Experience-based Reputation Models for Future Web Service Provisioning %X This paper concerns the applicability of reputations systems for assessing Quality of Experience (QoE) for web services in Future Internet. Reputation systems provide mechanisms to manage subjective opinions in societies and yield general scoring of a particular behavior. Thus, they are likely to become an important ingredient of Future Internet. Parameters being under evaluation by reputation system may vary greatly and, particularly, may be chosen to assess the users’ satisfaction with (composite) web services. Currently, this satisfaction is usually expressed with QoE, which represents subjective users’ opinions. The goal is to predict users’ satisfaction based on reputation values. This may be beneficial for service providers in terms of checking the fulfillment of SLAs, for retaining QoE on the satisfaction level for other users sharing the same network or service resources, and for providing the users with indications which resource to choose in order to maximize its experience.
• Wireless Mesh Network Planning and Optimization through Genetic Algorithms. Pries, Rastin; Staehle, Dirk; Stoykova, Marieta; Staehle, Barbara; Tran-Gia, Phuoc. In The Second International Conference on Advances in Mesh Networks, MESH 2009, p. 7. Athens/Glyfada, Greece, 2009.
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  Wireless Mesh Networks (WMNs) are a promising technology for providing broadband wireless access to the end user. They offer a higher degree of flexibility compared to traditional networks but on the expense of a more complex structure. Thus, planning and optimization of WMNs is a challenge. In this paper, we address this challenge using genetic algorithms. Genetic algorithms are able to evaluate and optimize large-scale WMNs in relatively small computation time. The results prove the effectiveness of the genetic operators to optimize the routing and channel assignment in WMNs.

  @inproceedings{info3-inproceedings-2009-347, abstract = {Wireless Mesh Networks (WMNs) are a promising technology for providing broadband wireless access to the end user. They offer a higher degree of flexibility compared to traditional networks but on the expense of a more complex structure. Thus, planning and optimization of WMNs is a challenge. In this paper, we address this challenge using genetic algorithms. Genetic algorithms are able to evaluate and optimize large-scale WMNs in relatively small computation time. The results prove the effectiveness of the genetic operators to optimize the routing and channel assignment in WMNs.}, address = {Athens/Glyfada, Greece}, author = {Pries, Rastin and Staehle, Dirk and Stoykova, Marieta and Staehle, Barbara and Tran-Gia, Phuoc}, booktitle = {The Second International Conference on Advances in Mesh Networks, MESH 2009}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = 7, title = {Wireless Mesh Network Planning and Optimization through Genetic Algorithms}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-347 %A Pries, Rastin %A Staehle, Dirk %A Stoykova, Marieta %A Staehle, Barbara %A Tran-Gia, Phuoc %B The Second International Conference on Advances in Mesh Networks, MESH 2009 %C Athens/Glyfada, Greece %D 2009 %P 7 %T Wireless Mesh Network Planning and Optimization through Genetic Algorithms %X Wireless Mesh Networks (WMNs) are a promising technology for providing broadband wireless access to the end user. They offer a higher degree of flexibility compared to traditional networks but on the expense of a more complex structure. Thus, planning and optimization of WMNs is a challenge. In this paper, we address this challenge using genetic algorithms. Genetic algorithms are able to evaluate and optimize large-scale WMNs in relatively small computation time. The results prove the effectiveness of the genetic operators to optimize the routing and channel assignment in WMNs.
• Marking Conversion for Pre-Congestion Notification. Lehrieder, Frank; Menth, Michael. In IEEE International Conference on Communications (ICC). Dresden, Germany, 2009.
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  Pre-congestion notification (PCN) defines admissible rates (AR) and supportable rates (SR) per link and marks the PCN traffic rate above these thresholds as AR- or SR-overload. The IETF standardizes simple mechanisms for admission control (AC) and flow termination (FT) based on this PCN-feedback for high-priority DiffServ traffic. While admission control (AC) has been extensively discussed in the literature, flow termination (FT) is a new control function. In this paper we propose an algorithm that converts marked AR-overload into marked SRoverload by unmarking appropriate packets. Classic marked flow termination (MFT) is based on marked SR-overload and works well even with a small number of PCN flows per ingress-egress aggregate and in case of multipath routing. Thanks to the new marking converter MFT also works with marked AR-overload so that a single marking scheme suffices to support AC and FT. We investigate whether MFT with marking conversion based on AR-overload retains the benefits classic MFT.

  @inproceedings{info3-inproceedings-2009-338, abstract = {Pre-congestion notification (PCN) defines admissible rates (AR) and supportable rates (SR) per link and marks the PCN traffic rate above these thresholds as AR- or SR-overload. The IETF standardizes simple mechanisms for admission control (AC) and flow termination (FT) based on this PCN-feedback for high-priority DiffServ traffic. While admission control (AC) has been extensively discussed in the literature, flow termination (FT) is a new control function. In this paper we propose an algorithm that converts marked AR-overload into marked SRoverload by unmarking appropriate packets. Classic marked flow termination (MFT) is based on marked SR-overload and works well even with a small number of PCN flows per ingress-egress aggregate and in case of multipath routing. Thanks to the new marking converter MFT also works with marked AR-overload so that a single marking scheme suffices to support AC and FT. We investigate whether MFT with marking conversion based on AR-overload retains the benefits classic MFT.}, address = {Dresden, Germany}, author = {Lehrieder, Frank and Menth, Michael}, booktitle = {IEEE International Conference on Communications (ICC)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Marking Conversion for Pre-Congestion Notification}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-338 %A Lehrieder, Frank %A Menth, Michael %B IEEE International Conference on Communications (ICC) %C Dresden, Germany %D 2009 %T Marking Conversion for Pre-Congestion Notification %X Pre-congestion notification (PCN) defines admissible rates (AR) and supportable rates (SR) per link and marks the PCN traffic rate above these thresholds as AR- or SR-overload. The IETF standardizes simple mechanisms for admission control (AC) and flow termination (FT) based on this PCN-feedback for high-priority DiffServ traffic. While admission control (AC) has been extensively discussed in the literature, flow termination (FT) is a new control function. In this paper we propose an algorithm that converts marked AR-overload into marked SRoverload by unmarking appropriate packets. Classic marked flow termination (MFT) is based on marked SR-overload and works well even with a small number of PCN flows per ingress-egress aggregate and in case of multipath routing. Thanks to the new marking converter MFT also works with marked AR-overload so that a single marking scheme suffices to support AC and FT. We investigate whether MFT with marking conversion based on AR-overload retains the benefits classic MFT.
• Effects of Link Rate Assignment on the Max-Min Fair Throughput of Wireless Mesh Networks. Staehle, Barbara; Staehle, Dirk; Pries, Rastin. In 21st International Teletraffic Congress (ITC 21). Paris, France, 2009.
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  Wireless mesh networks (WMNs) support a variety of modulation and coding schemes (MCSs) and hence enable adaptive modulation and coding. On the one hand, adaptive modulation and coding significantly increases the overall system capacity, as it allows to maximize the throughput on each link in dependence of the channel conditions. On the other hand, there is a trade-off between link data rate and spatial reuse, as high data rate links are less robust against interference. For maximizing the wireless mesh network performance, an intelligent link rate assignment strategy is thus required. By evaluating the maxmin fair WMN throughput under different link rate assignment strategies, we are able to show that using more robust MCSs improve the overall WMN throughput and point out directions towards an optimized MCS choice.

  @inproceedings{info3-inproceedings-2009-351, abstract = {Wireless mesh networks (WMNs) support a variety of modulation and coding schemes (MCSs) and hence enable adaptive modulation and coding. On the one hand, adaptive modulation and coding significantly increases the overall system capacity, as it allows to maximize the throughput on each link in dependence of the channel conditions. On the other hand, there is a trade-off between link data rate and spatial reuse, as high data rate links are less robust against interference. For maximizing the wireless mesh network performance, an intelligent link rate assignment strategy is thus required. By evaluating the maxmin fair WMN throughput under different link rate assignment strategies, we are able to show that using more robust MCSs improve the overall WMN throughput and point out directions towards an optimized MCS choice.}, address = {Paris, France}, author = {Staehle, Barbara and Staehle, Dirk and Pries, Rastin}, booktitle = {21st International Teletraffic Congress (ITC 21)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Effects of Link Rate Assignment on the Max-Min Fair Throughput of Wireless Mesh Networks}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-351 %A Staehle, Barbara %A Staehle, Dirk %A Pries, Rastin %B 21st International Teletraffic Congress (ITC 21) %C Paris, France %D 2009 %T Effects of Link Rate Assignment on the Max-Min Fair Throughput of Wireless Mesh Networks %X Wireless mesh networks (WMNs) support a variety of modulation and coding schemes (MCSs) and hence enable adaptive modulation and coding. On the one hand, adaptive modulation and coding significantly increases the overall system capacity, as it allows to maximize the throughput on each link in dependence of the channel conditions. On the other hand, there is a trade-off between link data rate and spatial reuse, as high data rate links are less robust against interference. For maximizing the wireless mesh network performance, an intelligent link rate assignment strategy is thus required. By evaluating the maxmin fair WMN throughput under different link rate assignment strategies, we are able to show that using more robust MCSs improve the overall WMN throughput and point out directions towards an optimized MCS choice.
• A Discussion of Socio-economic Management and Incentives for the Future Internet. Stiller, Burkhard; Hausheer, David; Hoßfeld, Tobias; Liotta, Antonio; Spirou, Spiros; Waldburger, Martin. In 2nd International Workshop on the Network of the Future (FutureNet II) in conjunction with IEEE GLOBECOM 2009. Honolulu, Hawaii, 2009.
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  This paper outlines the outcome of a socioeconomics (SE) and incentives work group during the “Management of the Future Internet” seminar, held in Dagstuhl, Germany. This covers an indication of key questions and issues, which are classified as important for next steps in network management. Furthermore, the process of dealing with aspects of “Socio-economic Management” is discussed, which determines a hybrid and innovative approach besides traditional network management approaches. This determines a network management in which control is delegated via socio-economic means and to a certain extend to the user and provider with the goal to maximize the overall social welfare and the networks technical efficiency at the same time. This is refined by a set of SE-driven management mechanisms, the discussion of a practical user/network interface proposal, and an example case for managing overlay traffic in such a network management system. Finally, based on a set of ideal SE requirements derived from the analysis of existing approaches, a set of preliminary conclusions is drawn.

  @inproceedings{info3-inproceedings-2009-361, abstract = {This paper outlines the outcome of a socioeconomics (SE) and incentives work group during the “Management of the Future Internet” seminar, held in Dagstuhl, Germany. This covers an indication of key questions and issues, which are classified as important for next steps in network management. Furthermore, the process of dealing with aspects of “Socio-economic Management” is discussed, which determines a hybrid and innovative approach besides traditional network management approaches. This determines a network management in which control is delegated via socio-economic means and to a certain extend to the user and provider with the goal to maximize the overall social welfare and the networks technical efficiency at the same time. This is refined by a set of SE-driven management mechanisms, the discussion of a practical user/network interface proposal, and an example case for managing overlay traffic in such a network management system. Finally, based on a set of ideal SE requirements derived from the analysis of existing approaches, a set of preliminary conclusions is drawn.}, address = {Honolulu, Hawaii}, author = {Stiller, Burkhard and Hausheer, David and Hoßfeld, Tobias and Liotta, Antonio and Spirou, Spiros and Waldburger, Martin}, booktitle = {2nd International Workshop on the Network of the Future (FutureNet II) in conjunction with IEEE GLOBECOM 2009}, keywords = {sys:hidden:inproceedings}, month = 12, title = {A Discussion of Socio-economic Management and Incentives for the Future Internet}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-361 %A Stiller, Burkhard %A Hausheer, David %A Hoßfeld, Tobias %A Liotta, Antonio %A Spirou, Spiros %A Waldburger, Martin %B 2nd International Workshop on the Network of the Future (FutureNet II) in conjunction with IEEE GLOBECOM 2009 %C Honolulu, Hawaii %D 2009 %T A Discussion of Socio-economic Management and Incentives for the Future Internet %X This paper outlines the outcome of a socioeconomics (SE) and incentives work group during the “Management of the Future Internet” seminar, held in Dagstuhl, Germany. This covers an indication of key questions and issues, which are classified as important for next steps in network management. Furthermore, the process of dealing with aspects of “Socio-economic Management” is discussed, which determines a hybrid and innovative approach besides traditional network management approaches. This determines a network management in which control is delegated via socio-economic means and to a certain extend to the user and provider with the goal to maximize the overall social welfare and the networks technical efficiency at the same time. This is refined by a set of SE-driven management mechanisms, the discussion of a practical user/network interface proposal, and an example case for managing overlay traffic in such a network management system. Finally, based on a set of ideal SE requirements derived from the analysis of existing approaches, a set of preliminary conclusions is drawn.
• Performance Evaluation Framework for Video Applications in Mobile Networks. Klein, Alexander; Klaue, Jirka. In The Second International Conference on Advances in Mesh Networks, MESH 2009, p. 7. Athens, Greece, 2009.
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  @inproceedings{info3-inproceedings-2009-346, address = {Athens, Greece}, author = {Klein, Alexander and Klaue, Jirka}, booktitle = {The Second International Conference on Advances in Mesh Networks, MESH 2009}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = 7, title = {Performance Evaluation Framework for Video Applications in Mobile Networks}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-346 %A Klein, Alexander %A Klaue, Jirka %B The Second International Conference on Advances in Mesh Networks, MESH 2009 %C Athens, Greece %D 2009 %P 7 %T Performance Evaluation Framework for Video Applications in Mobile Networks
• Measuring One-Way Delay in Wireless Mesh Networks - An Experimental Investigation. Staehle, Barbara; Staehle, Dirk; Pries, Rastin; Hirth, Matthias; Kassler, Andreas; Dely, Peter. In 4-th ACM Workshop on Performance Monitoring and Measurement of Heterogeneous Wireless and Wired Networks (PM2HW2N 2009). Tenerife, Canary Islands, Spain, 2009.
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  Wireless Mesh networks are multi-hop networks mostly based on IEEE 802.11 technology and are considered as a viable alternative for providing broadband wireless Internet access. As a consequence, they require support for Quality of Service or advanced mechanisms for selecting Internet gateways. One important required information is the one-way delay between different nodes. In this paper, we have developed, implemented, and evaluated an one-way delay estimation technique for wireless mesh networks which is based on estimating intra node queuing and inter node forwarding delay. An IP-header option field is used to accumulate the per hop delay estimate to provide an end-to-end estimate. We also outline problems with the implementation and compare results with real one-way delays obtained from a 14 node mesh testbed. We show how estimation accuracy depends on network load and provide insights into further improvements.

  @inproceedings{info3-inproceedings-2009-359, abstract = {Wireless Mesh networks are multi-hop networks mostly based on IEEE 802.11 technology and are considered as a viable alternative for providing broadband wireless Internet access. As a consequence, they require support for Quality of Service or advanced mechanisms for selecting Internet gateways. One important required information is the one-way delay between different nodes. In this paper, we have developed, implemented, and evaluated an one-way delay estimation technique for wireless mesh networks which is based on estimating intra node queuing and inter node forwarding delay. An IP-header option field is used to accumulate the per hop delay estimate to provide an end-to-end estimate. We also outline problems with the implementation and compare results with real one-way delays obtained from a 14 node mesh testbed. We show how estimation accuracy depends on network load and provide insights into further improvements.}, address = {Tenerife, Canary Islands, Spain}, author = {Staehle, Barbara and Staehle, Dirk and Pries, Rastin and Hirth, Matthias and Kassler, Andreas and Dely, Peter}, booktitle = {4-th ACM Workshop on Performance Monitoring and Measurement of Heterogeneous Wireless and Wired Networks (PM2HW2N 2009)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Measuring One-Way Delay in Wireless Mesh Networks - An Experimental Investigation}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-359 %A Staehle, Barbara %A Staehle, Dirk %A Pries, Rastin %A Hirth, Matthias %A Kassler, Andreas %A Dely, Peter %B 4-th ACM Workshop on Performance Monitoring and Measurement of Heterogeneous Wireless and Wired Networks (PM2HW2N 2009) %C Tenerife, Canary Islands, Spain %D 2009 %T Measuring One-Way Delay in Wireless Mesh Networks - An Experimental Investigation %X Wireless Mesh networks are multi-hop networks mostly based on IEEE 802.11 technology and are considered as a viable alternative for providing broadband wireless Internet access. As a consequence, they require support for Quality of Service or advanced mechanisms for selecting Internet gateways. One important required information is the one-way delay between different nodes. In this paper, we have developed, implemented, and evaluated an one-way delay estimation technique for wireless mesh networks which is based on estimating intra node queuing and inter node forwarding delay. An IP-header option field is used to accumulate the per hop delay estimate to provide an end-to-end estimate. We also outline problems with the implementation and compare results with real one-way delays obtained from a 14 node mesh testbed. We show how estimation accuracy depends on network load and provide insights into further improvements.
• Performance Evaluation and Parameterization of the IEEE 802.16 Contention-Based CDMA Bandwidth Request Mechanism for the OFDMA Physical Layer. Staehle, Dirk; Pries, Rastin; Vinel, Alexey; Mäder, Andreas. In Proceedings of the 12th ACM international conference on Modeling, analysis and simulation of wireless and mobile systems. Tenerife, Canary Islands, Spain, 2009.
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  The IEEE 802.16 standard specifies two contention-based mechanisms for the OFDMA physical layer to transmit bandwidth requests from subscriber station to base station: the standard mechanism is based on Slotted Aloha with a truncated binary exponential backoff; the alternative one is based on CDMA. This paper describes the CDMA-based contention mechanism and presents an analytic model to compute its performance in terms of delay and consumed resources. The tunable parameters for the CDMA-based random access procedure are the number of ranging subchannels, the number of codes per ranging subchannels, and the detection threshold. An optimal configuration is derived for a given load in terms of the request arrival rate.

  @inproceedings{info3-inproceedings-2009-373, abstract = {The IEEE 802.16 standard specifies two contention-based mechanisms for the OFDMA physical layer to transmit bandwidth requests from subscriber station to base station: the standard mechanism is based on Slotted Aloha with a truncated binary exponential backoff; the alternative one is based on CDMA. This paper describes the CDMA-based contention mechanism and presents an analytic model to compute its performance in terms of delay and consumed resources. The tunable parameters for the CDMA-based random access procedure are the number of ranging subchannels, the number of codes per ranging subchannels, and the detection threshold. An optimal configuration is derived for a given load in terms of the request arrival rate.}, address = {Tenerife, Canary Islands, Spain}, author = {Staehle, Dirk and Pries, Rastin and Vinel, Alexey and Mäder, Andreas}, booktitle = {Proceedings of the 12th ACM international conference on Modeling, analysis and simulation of wireless and mobile systems}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Performance Evaluation and Parameterization of the IEEE 802.16 Contention-Based CDMA Bandwidth Request Mechanism for the OFDMA Physical Layer}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-373 %A Staehle, Dirk %A Pries, Rastin %A Vinel, Alexey %A Mäder, Andreas %B Proceedings of the 12th ACM international conference on Modeling, analysis and simulation of wireless and mobile systems %C Tenerife, Canary Islands, Spain %D 2009 %T Performance Evaluation and Parameterization of the IEEE 802.16 Contention-Based CDMA Bandwidth Request Mechanism for the OFDMA Physical Layer %X The IEEE 802.16 standard specifies two contention-based mechanisms for the OFDMA physical layer to transmit bandwidth requests from subscriber station to base station: the standard mechanism is based on Slotted Aloha with a truncated binary exponential backoff; the alternative one is based on CDMA. This paper describes the CDMA-based contention mechanism and presents an analytic model to compute its performance in terms of delay and consumed resources. The tunable parameters for the CDMA-based random access procedure are the number of ranging subchannels, the number of codes per ranging subchannels, and the detection threshold. An optimal configuration is derived for a given load in terms of the request arrival rate.
• Objective Functions for Optimization of Resilient and Non-Resilient IP Routing. Hartmann, Matthias; Hock, David; Menth, Michael; Schwartz, Christian. In 7th International Workshop on the Design of Reliable Communication Networks (DRCN). Washington, D.C., USA, 2009.
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  Intradomain routing in IP networks follows leastcost paths according to administrative link costs. Routing optimization modifies these values to minimize an objective function for a network with given link capacities and traffic matrix. An example for an objective function is the maximum utilization of all links under failure-free conditions or also after rerouting in case of network failures. Many papers have provided heuristic algorithms for routing optimization using different objective functions, but the investigation and comparison of various objective functions has not attracted much attention so far. In this work we present several objective functions for resilient IP routing. We also propose a new combined optimization approach which can simultaneously optimize different objective functions with almost no additional computation effort and describe new techniques to minimize overall computation time. The different objective functions and combinations thereof are then analyzed and compared experimentally.

  @inproceedings{info3-inproceedings-2009-358, abstract = {Intradomain routing in IP networks follows leastcost paths according to administrative link costs. Routing optimization modifies these values to minimize an objective function for a network with given link capacities and traffic matrix. An example for an objective function is the maximum utilization of all links under failure-free conditions or also after rerouting in case of network failures. Many papers have provided heuristic algorithms for routing optimization using different objective functions, but the investigation and comparison of various objective functions has not attracted much attention so far. In this work we present several objective functions for resilient IP routing. We also propose a new combined optimization approach which can simultaneously optimize different objective functions with almost no additional computation effort and describe new techniques to minimize overall computation time. The different objective functions and combinations thereof are then analyzed and compared experimentally.}, address = {Washington, D.C., USA}, author = {Hartmann, Matthias and Hock, David and Menth, Michael and Schwartz, Christian}, booktitle = {7th International Workshop on the Design of Reliable Communication Networks (DRCN)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Objective Functions for Optimization of Resilient and Non-Resilient IP Routing}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-358 %A Hartmann, Matthias %A Hock, David %A Menth, Michael %A Schwartz, Christian %B 7th International Workshop on the Design of Reliable Communication Networks (DRCN) %C Washington, D.C., USA %D 2009 %T Objective Functions for Optimization of Resilient and Non-Resilient IP Routing %X Intradomain routing in IP networks follows leastcost paths according to administrative link costs. Routing optimization modifies these values to minimize an objective function for a network with given link capacities and traffic matrix. An example for an objective function is the maximum utilization of all links under failure-free conditions or also after rerouting in case of network failures. Many papers have provided heuristic algorithms for routing optimization using different objective functions, but the investigation and comparison of various objective functions has not attracted much attention so far. In this work we present several objective functions for resilient IP routing. We also propose a new combined optimization approach which can simultaneously optimize different objective functions with almost no additional computation effort and describe new techniques to minimize overall computation time. The different objective functions and combinations thereof are then analyzed and compared experimentally.
• P2P Solutions for Cellular Networks. Berl, Andreas; de Meer, Hermann; Hoßfeld, Tobias. In International Conference on Advances in P2P Systems (AP2PS 2009). Sliema, Malta, 2009.
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  The participation of stationary computers with highbandwidth links in peer-to-peer content-distribution networks is highly popular. Mobile devices (e.g. cell phones), however, could not yet be launched into the field to a satisfactory extent. This paper discusses mobile peer-to-peer approaches that cover this issue and compares two promising approaches in detail. The first approach supports mobile devices by adding new infrastructure elements to the mobile network operator’s domain. In the second approach, voluntary peers provide support for mobile devices. Both approaches are able to foster the integration of mobile devices into peer-to-peer networks with a large user community.

  @inproceedings{info3-inproceedings-2009-357, abstract = {The participation of stationary computers with highbandwidth links in peer-to-peer content-distribution networks is highly popular. Mobile devices (e.g. cell phones), however, could not yet be launched into the field to a satisfactory extent. This paper discusses mobile peer-to-peer approaches that cover this issue and compares two promising approaches in detail. The first approach supports mobile devices by adding new infrastructure elements to the mobile network operator’s domain. In the second approach, voluntary peers provide support for mobile devices. Both approaches are able to foster the integration of mobile devices into peer-to-peer networks with a large user community.}, address = {Sliema, Malta}, author = {Berl, Andreas and de Meer, Hermann and Hoßfeld, Tobias}, booktitle = {International Conference on Advances in P2P Systems (AP2PS 2009)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {P2P Solutions for Cellular Networks}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-357 %A Berl, Andreas %A de Meer, Hermann %A Hoßfeld, Tobias %B International Conference on Advances in P2P Systems (AP2PS 2009) %C Sliema, Malta %D 2009 %T P2P Solutions for Cellular Networks %X The participation of stationary computers with highbandwidth links in peer-to-peer content-distribution networks is highly popular. Mobile devices (e.g. cell phones), however, could not yet be launched into the field to a satisfactory extent. This paper discusses mobile peer-to-peer approaches that cover this issue and compares two promising approaches in detail. The first approach supports mobile devices by adding new infrastructure elements to the mobile network operator’s domain. In the second approach, voluntary peers provide support for mobile devices. Both approaches are able to foster the integration of mobile devices into peer-to-peer networks with a large user community.
• Modeling of Modern Router Architectures Supporting Network Virtualization. Hoßfeld, Tobias; Leibnitz, Kenji; Nakao, Akihiro. In 2nd International Workshop on the Network of the Future (FutureNet II) in conjunction with IEEE GLOBECOM 2009. Honolulu, Hawaii, 2009.
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  For the emerging concept of network virtualization where a multitude of virtual networks (VNs) coexist, the main challenge is to isolate and control the resources allocated for individual virtual networks. Realizing such resource allocation requires deliberate design of the router enhanced specifically for handling a large number of virtual network flows. This paper discusses fundamental challenges on modeling the architecture of modern routers for the support of the virtual networks. Our intention is to discuss strategies for scheduling the traffic on each isolated VN and to provide an elementary framework for evaluating the performance of the router extended to classify incoming VN traffic. Furthermore, we also present simulation results and discuss challenges and future directions encountered in the implementation and deployment of VNs.

  @inproceedings{info3-inproceedings-2009-362, abstract = {For the emerging concept of network virtualization where a multitude of virtual networks (VNs) coexist, the main challenge is to isolate and control the resources allocated for individual virtual networks. Realizing such resource allocation requires deliberate design of the router enhanced specifically for handling a large number of virtual network flows. This paper discusses fundamental challenges on modeling the architecture of modern routers for the support of the virtual networks. Our intention is to discuss strategies for scheduling the traffic on each isolated VN and to provide an elementary framework for evaluating the performance of the router extended to classify incoming VN traffic. Furthermore, we also present simulation results and discuss challenges and future directions encountered in the implementation and deployment of VNs.}, address = {Honolulu, Hawaii}, author = {Hoßfeld, Tobias and Leibnitz, Kenji and Nakao, Akihiro}, booktitle = {2nd International Workshop on the Network of the Future (FutureNet II) in conjunction with IEEE GLOBECOM 2009}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Modeling of Modern Router Architectures Supporting Network Virtualization}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-362 %A Hoßfeld, Tobias %A Leibnitz, Kenji %A Nakao, Akihiro %B 2nd International Workshop on the Network of the Future (FutureNet II) in conjunction with IEEE GLOBECOM 2009 %C Honolulu, Hawaii %D 2009 %T Modeling of Modern Router Architectures Supporting Network Virtualization %X For the emerging concept of network virtualization where a multitude of virtual networks (VNs) coexist, the main challenge is to isolate and control the resources allocated for individual virtual networks. Realizing such resource allocation requires deliberate design of the router enhanced specifically for handling a large number of virtual network flows. This paper discusses fundamental challenges on modeling the architecture of modern routers for the support of the virtual networks. Our intention is to discuss strategies for scheduling the traffic on each isolated VN and to provide an elementary framework for evaluating the performance of the router extended to classify incoming VN traffic. Furthermore, we also present simulation results and discuss challenges and future directions encountered in the implementation and deployment of VNs.
• Pushing the Performance of Biased Neighbor Selection through Biased Unchoking. Oechsner, Simon; Lehrieder, Frank; Hoßfeld, Tobias; Metzger, Florian; Pussep, Konstantin; Staehle, Dirk. In 9th International Conference on Peer-to-Peer Computing. Seattle, USA, 2009.
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  Locality promotion in P2P content distribution networks is currently a major research topic. One of the goals of all discussed approaches is to reduce the interdomain traffic that causes high costs for ISPs. However, the focus of the work in this field is generally on the type of locality information that is provided to the overlay and on the entities that exchange this information. An aspect that is generally neglected is how this information is used by the peers. In this paper, we consider the predominant approach of Biased Neighbor Selection and compare it with Biased Unchoking, an alternative locality aware peer selection strategy we propose in this paper. We show that both mechanisms complement each other for the BitTorrent file sharing application and achieve the best performance when combined.

  @inproceedings{info3-inproceedings-2009-355, abstract = {Locality promotion in P2P content distribution networks is currently a major research topic. One of the goals of all discussed approaches is to reduce the interdomain traffic that causes high costs for ISPs. However, the focus of the work in this field is generally on the type of locality information that is provided to the overlay and on the entities that exchange this information. An aspect that is generally neglected is how this information is used by the peers. In this paper, we consider the predominant approach of Biased Neighbor Selection and compare it with Biased Unchoking, an alternative locality aware peer selection strategy we propose in this paper. We show that both mechanisms complement each other for the BitTorrent file sharing application and achieve the best performance when combined.}, address = {Seattle, USA}, author = {Oechsner, Simon and Lehrieder, Frank and Hoßfeld, Tobias and Metzger, Florian and Pussep, Konstantin and Staehle, Dirk}, booktitle = {9th International Conference on Peer-to-Peer Computing}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Pushing the Performance of Biased Neighbor Selection through Biased Unchoking}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-355 %A Oechsner, Simon %A Lehrieder, Frank %A Hoßfeld, Tobias %A Metzger, Florian %A Pussep, Konstantin %A Staehle, Dirk %B 9th International Conference on Peer-to-Peer Computing %C Seattle, USA %D 2009 %T Pushing the Performance of Biased Neighbor Selection through Biased Unchoking %X Locality promotion in P2P content distribution networks is currently a major research topic. One of the goals of all discussed approaches is to reduce the interdomain traffic that causes high costs for ISPs. However, the focus of the work in this field is generally on the type of locality information that is provided to the overlay and on the entities that exchange this information. An aspect that is generally neglected is how this information is used by the peers. In this paper, we consider the predominant approach of Biased Neighbor Selection and compare it with Biased Unchoking, an alternative locality aware peer selection strategy we propose in this paper. We show that both mechanisms complement each other for the BitTorrent file sharing application and achieve the best performance when combined.
• On the Unfair Channel Access Phenomenon in Wireless LANs. Pries, Rastin; Staehle, Dirk; Oechsner, Simon; Menth, Michael; Menth, Stefan; Tran-Gia, Phuoc. In 21st International Teletraffic Congress (ITC 21). Paris, France, 2009.
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  This paper shows that the relative collision probability for packets in Wireless LAN 802.11 networks decreases with increasing load offered by the respective station. This denotes a clearly unfair channel access which is important to be aware of, e.g., when collision probabilities are measured and used for reactive control of contention windows. We model the unfair channel access phenomenon analytically and semi-analytically for bidirectional constant bit rate and unidirectional TCP traffic and compare the results with those from simulations.

  @inproceedings{info3-inproceedings-2009-352, abstract = {This paper shows that the relative collision probability for packets in Wireless LAN 802.11 networks decreases with increasing load offered by the respective station. This denotes a clearly unfair channel access which is important to be aware of, e.g., when collision probabilities are measured and used for reactive control of contention windows. We model the unfair channel access phenomenon analytically and semi-analytically for bidirectional constant bit rate and unidirectional TCP traffic and compare the results with those from simulations.}, address = {Paris, France}, author = {Pries, Rastin and Staehle, Dirk and Oechsner, Simon and Menth, Michael and Menth, Stefan and Tran-Gia, Phuoc}, booktitle = {21st International Teletraffic Congress (ITC 21)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {On the Unfair Channel Access Phenomenon in Wireless LANs}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-352 %A Pries, Rastin %A Staehle, Dirk %A Oechsner, Simon %A Menth, Michael %A Menth, Stefan %A Tran-Gia, Phuoc %B 21st International Teletraffic Congress (ITC 21) %C Paris, France %D 2009 %T On the Unfair Channel Access Phenomenon in Wireless LANs %X This paper shows that the relative collision probability for packets in Wireless LAN 802.11 networks decreases with increasing load offered by the respective station. This denotes a clearly unfair channel access which is important to be aware of, e.g., when collision probabilities are measured and used for reactive control of contention windows. We model the unfair channel access phenomenon analytically and semi-analytically for bidirectional constant bit rate and unidirectional TCP traffic and compare the results with those from simulations.
• On Traffic Characteristics of a Broadband Wireless Internet Access. Pries, Rastin; Wamser, Florian; Staehle, Dirk; Heck, Klaus; Tran-Gia, Phuoc. In Next Generation Internet Networks 2009 (NGI 2009). Aveiro, Portugal, 2009.
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  Internet traffic measurements and traffic characterization are essential for managing and optimizing network infrastructures. The increasing number of wireless Internet users and the changing application demands require consecutive traffic measurements. Therefore, we have performed measurements of home users at a broadband wireless access service provider in order to reflect the current traffic characteristics. In this paper, we present the results of these measurements like application distributions as well as changing traffic characteristics caused by user demands and new services. The results are used by a network service provider to optimize its network performance in order to give Quality of Service (QoS) guarantees for home users in its fixed wireless network.

  @inproceedings{info3-inproceedings-2009-350, abstract = {Internet traffic measurements and traffic characterization are essential for managing and optimizing network infrastructures. The increasing number of wireless Internet users and the changing application demands require consecutive traffic measurements. Therefore, we have performed measurements of home users at a broadband wireless access service provider in order to reflect the current traffic characteristics. In this paper, we present the results of these measurements like application distributions as well as changing traffic characteristics caused by user demands and new services. The results are used by a network service provider to optimize its network performance in order to give Quality of Service (QoS) guarantees for home users in its fixed wireless network.}, address = {Aveiro, Portugal}, author = {Pries, Rastin and Wamser, Florian and Staehle, Dirk and Heck, Klaus and Tran-Gia, Phuoc}, booktitle = {Next Generation Internet Networks 2009 (NGI 2009)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {On Traffic Characteristics of a Broadband Wireless Internet Access}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-350 %A Pries, Rastin %A Wamser, Florian %A Staehle, Dirk %A Heck, Klaus %A Tran-Gia, Phuoc %B Next Generation Internet Networks 2009 (NGI 2009) %C Aveiro, Portugal %D 2009 %T On Traffic Characteristics of a Broadband Wireless Internet Access %X Internet traffic measurements and traffic characterization are essential for managing and optimizing network infrastructures. The increasing number of wireless Internet users and the changing application demands require consecutive traffic measurements. Therefore, we have performed measurements of home users at a broadband wireless access service provider in order to reflect the current traffic characteristics. In this paper, we present the results of these measurements like application distributions as well as changing traffic characteristics caused by user demands and new services. The results are used by a network service provider to optimize its network performance in order to give Quality of Service (QoS) guarantees for home users in its fixed wireless network.
• CAPEX-Aware Design of Survivable DWDM Mesh Networks. Pluntke, Christopher; Menth, Michael; Duelli, Michael. In IEEE International Conference on Communications (ICC). Dresden, Germany, 2009.
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  This paper reviews the basic architecture and component costs of opaque, transparent, and semi-transparent DWDM networks and looks at the network design problem from a capital expenditure (CAPEX) point of view. Given are a fiber topology and a demand matrix with different bit rates. Required is the least-cost optical equipment for that topology together with the routing and potential muxponder-based aggregation of all demands such that they can be supported by the newly designed network. We look at the problem for networks without resilience requirements and for survivable networks using 1+1 protection against single fiber cuts. We model this problem for the three types of optical networks by integer linear programs (ILPs) in a canonical way.

  @inproceedings{info3-inproceedings-2009-342, abstract = {This paper reviews the basic architecture and component costs of opaque, transparent, and semi-transparent DWDM networks and looks at the network design problem from a capital expenditure (CAPEX) point of view. Given are a fiber topology and a demand matrix with different bit rates. Required is the least-cost optical equipment for that topology together with the routing and potential muxponder-based aggregation of all demands such that they can be supported by the newly designed network. We look at the problem for networks without resilience requirements and for survivable networks using 1+1 protection against single fiber cuts. We model this problem for the three types of optical networks by integer linear programs (ILPs) in a canonical way.}, address = {Dresden, Germany}, author = {Pluntke, Christopher and Menth, Michael and Duelli, Michael}, booktitle = {IEEE International Conference on Communications (ICC)}, keywords = {100get}, month = {06}, title = {CAPEX-Aware Design of Survivable DWDM Mesh Networks}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-342 %A Pluntke, Christopher %A Menth, Michael %A Duelli, Michael %B IEEE International Conference on Communications (ICC) %C Dresden, Germany %D 2009 %T CAPEX-Aware Design of Survivable DWDM Mesh Networks %X This paper reviews the basic architecture and component costs of opaque, transparent, and semi-transparent DWDM networks and looks at the network design problem from a capital expenditure (CAPEX) point of view. Given are a fiber topology and a demand matrix with different bit rates. Required is the least-cost optical equipment for that topology together with the routing and potential muxponder-based aggregation of all demands such that they can be supported by the newly designed network. We look at the problem for networks without resilience requirements and for survivable networks using 1+1 protection against single fiber cuts. We model this problem for the three types of optical networks by integer linear programs (ILPs) in a canonical way.
• A Genetic Approach for Wireless Mesh Network Planning and Optimization. Pries, Rastin; Staehle, Dirk; Stoykova, Marieta; Staehle, Barbara; Tran-Gia, Phuoc. In IWCMC 2009 Planning and Optimization of Wireless Communication Networks (PlanNet). Leipzig, Germany, 2009.
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  Wireless Mesh Networks (WMNs) are gaining an increasingly important role in next generation last mile access. They offer more flexibility compared to traditional networks but on the expense of a complex structure. Thus, planning and optimization of WMNs is a challenge. In this paper we focus on routing and channel assignment in WMNs for throughput maximization using genetic algorithms. Genetic algorithms provide a good solution for large-scale WMNs in relatively small computation time. The results prove the effectiveness of the genetic operators and show the advantages of a genetic optimization. However, these operators have to be configured carefully to avoid local optima. We will show the influence of the selection principles as well as evaluation functions on the optimization.

  @inproceedings{info3-inproceedings-2009-349, abstract = {Wireless Mesh Networks (WMNs) are gaining an increasingly important role in next generation last mile access. They offer more flexibility compared to traditional networks but on the expense of a complex structure. Thus, planning and optimization of WMNs is a challenge. In this paper we focus on routing and channel assignment in WMNs for throughput maximization using genetic algorithms. Genetic algorithms provide a good solution for large-scale WMNs in relatively small computation time. The results prove the effectiveness of the genetic operators and show the advantages of a genetic optimization. However, these operators have to be configured carefully to avoid local optima. We will show the influence of the selection principles as well as evaluation functions on the optimization.}, address = {Leipzig, Germany}, author = {Pries, Rastin and Staehle, Dirk and Stoykova, Marieta and Staehle, Barbara and Tran-Gia, Phuoc}, booktitle = {IWCMC 2009 Planning and Optimization of Wireless Communication Networks (PlanNet)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {A Genetic Approach for Wireless Mesh Network Planning and Optimization}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-349 %A Pries, Rastin %A Staehle, Dirk %A Stoykova, Marieta %A Staehle, Barbara %A Tran-Gia, Phuoc %B IWCMC 2009 Planning and Optimization of Wireless Communication Networks (PlanNet) %C Leipzig, Germany %D 2009 %T A Genetic Approach for Wireless Mesh Network Planning and Optimization %X Wireless Mesh Networks (WMNs) are gaining an increasingly important role in next generation last mile access. They offer more flexibility compared to traditional networks but on the expense of a complex structure. Thus, planning and optimization of WMNs is a challenge. In this paper we focus on routing and channel assignment in WMNs for throughput maximization using genetic algorithms. Genetic algorithms provide a good solution for large-scale WMNs in relatively small computation time. The results prove the effectiveness of the genetic operators and show the advantages of a genetic optimization. However, these operators have to be configured carefully to avoid local optima. We will show the influence of the selection principles as well as evaluation functions on the optimization.
• Network Planning, Control and Management Perspectives on Dynamic Networking. Michaelis, Thomas; Duelli, Michael; Chamania, Mohit; Lichtinger, Bernhard; Rambach, Franz; Türk, Stefan. In European Conference and Exhibition on Optical Communication (ECOC). Vienna, Austria, 2009.
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  Besides the frequently claimed cost savings due to automation, one major advantage of dynamic networking is that this networking paradigm matches the mode of operation which is observed in the Internet and is essential for making transport networks a native part of it. This talk highlights three essential ingredients of dynamic networking: Firstly, network planning creates the required degrees of freedom in the data plane for a dynamic control plane. Secondly, service provisioning and restoration provide the required agility for dynamic network operation, no matter if implemented on the management or on a control plane. Eventually, service management ensures adequate service performance across all involved network domains. We conclude that all of these aspects need to be addressed adequately in order to realize dynamic networking.

  @inproceedings{info3-inproceedings-2009-356, abstract = {Besides the frequently claimed cost savings due to automation, one major advantage of dynamic networking is that this networking paradigm matches the mode of operation which is observed in the Internet and is essential for making transport networks a native part of it. This talk highlights three essential ingredients of dynamic networking: Firstly, network planning creates the required degrees of freedom in the data plane for a dynamic control plane. Secondly, service provisioning and restoration provide the required agility for dynamic network operation, no matter if implemented on the management or on a control plane. Eventually, service management ensures adequate service performance across all involved network domains. We conclude that all of these aspects need to be addressed adequately in order to realize dynamic networking.}, address = {Vienna, Austria}, author = {Michaelis, Thomas and Duelli, Michael and Chamania, Mohit and Lichtinger, Bernhard and Rambach, Franz and Türk, Stefan}, booktitle = {European Conference and Exhibition on Optical Communication (ECOC)}, keywords = {100get}, month = {09}, title = {Network Planning, Control and Management Perspectives on Dynamic Networking}, year = 2009 }

  %0 Conference Paper %1 info3-inproceedings-2009-356 %A Michaelis, Thomas %A Duelli, Michael %A Chamania, Mohit %A Lichtinger, Bernhard %A Rambach, Franz %A Türk, Stefan %B European Conference and Exhibition on Optical Communication (ECOC) %C Vienna, Austria %D 2009 %T Network Planning, Control and Management Perspectives on Dynamic Networking %X Besides the frequently claimed cost savings due to automation, one major advantage of dynamic networking is that this networking paradigm matches the mode of operation which is observed in the Internet and is essential for making transport networks a native part of it. This talk highlights three essential ingredients of dynamic networking: Firstly, network planning creates the required degrees of freedom in the data plane for a dynamic control plane. Secondly, service provisioning and restoration provide the required agility for dynamic network operation, no matter if implemented on the management or on a control plane. Eventually, service management ensures adequate service performance across all involved network domains. We conclude that all of these aspects need to be addressed adequately in order to realize dynamic networking.

• Quantifying the Influence of Network Conditions on the Service Quality Experienced by a Thin Client User. Staehle, Barbara; Binzenhöfer, Andreas; Schlosser, Daniel; Boder, Björn. In 14. GI/ITG Konferenz Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen (MMB 2008). Dortmund, Germany, 2008.
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  Quality of Experience (QoE) is a measure for the satisfaction of a user with a given service. Despite the popularity of the term, there is a lack of understanding of how to capture or quantify QoE. In this paper we therefore take a step forward in this direction using the example of thin client architectures, where the client is only used as a dumb terminal while the applications run on a central server. The satisfaction of a thin client user is thus heavily influenced by the quality of the network connection between the client and the server. We study this influence by varying different network parameters like packet loss, jitter, and delay in a controlled testbed environment. The service quality is assessed using objective measurements on application level (oQoE) and verified by means of a survey among test persons capturing subjective user satisfactions (sQoE).

  @inproceedings{info3-inproceedings-2008-303, abstract = {Quality of Experience (QoE) is a measure for the satisfaction of a user with a given service. Despite the popularity of the term, there is a lack of understanding of how to capture or quantify QoE. In this paper we therefore take a step forward in this direction using the example of thin client architectures, where the client is only used as a dumb terminal while the applications run on a central server. The satisfaction of a thin client user is thus heavily influenced by the quality of the network connection between the client and the server. We study this influence by varying different network parameters like packet loss, jitter, and delay in a controlled testbed environment. The service quality is assessed using objective measurements on application level (oQoE) and verified by means of a survey among test persons capturing subjective user satisfactions (sQoE).}, address = {Dortmund, Germany}, author = {Staehle, Barbara and Binzenhöfer, Andreas and Schlosser, Daniel and Boder, Björn}, booktitle = {14. GI/ITG Konferenz Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen (MMB 2008)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Quantifying the Influence of Network Conditions on the Service Quality Experienced by a Thin Client User}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-303 %A Staehle, Barbara %A Binzenhöfer, Andreas %A Schlosser, Daniel %A Boder, Björn %B 14. GI/ITG Konferenz Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen (MMB 2008) %C Dortmund, Germany %D 2008 %T Quantifying the Influence of Network Conditions on the Service Quality Experienced by a Thin Client User %X Quality of Experience (QoE) is a measure for the satisfaction of a user with a given service. Despite the popularity of the term, there is a lack of understanding of how to capture or quantify QoE. In this paper we therefore take a step forward in this direction using the example of thin client architectures, where the client is only used as a dumb terminal while the applications run on a central server. The satisfaction of a thin client user is thus heavily influenced by the quality of the network connection between the client and the server. We study this influence by varying different network parameters like packet loss, jitter, and delay in a controlled testbed environment. The service quality is assessed using objective measurements on application level (oQoE) and verified by means of a survey among test persons capturing subjective user satisfactions (sQoE).
• Dynamic Bandwidth Control in Wireless Mesh Networks: A Quality of Experience based Approach. Pries, Rastin; Hock, David; Bayer, Nico; Siebert, Matthias; Staehle, Dirk; Rakocevic, Veselin; Xu, Bangnan; Tran-Gia, Phuoc. In 18th ITC Specialist Seminar on Quality of Experience. Karlskrona, Sweden, 2008.
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  Wireless Mesh Networks (WMNs) are gaining an increasingly important role in next generation wireless networks. Due to their advantages over other wireless and wired networks, WMNs are undergoing rapid progress and are supposed to deliver wireless services for a large variety of applications. Especially real-time applications such as voice over IP make high demands on wireless mesh networks. A small change of the Quality-of-Service (QoS) metrics like packet loss, delay, and jitter have a significant impact on the Quality-of-Experience (QoE), a subjective measure from the user perspective of the overall value of the provided service or application. In this paper, we present a dynamic bandwidth control mechanism which measures the current situation in the network and adapts the bandwidth in order to ensure a high QoE level. The mechanism is implemented in a Wireless LAN mesh testbed and the results show that real-time applications are successfully protected from disturbing best effort traffic flows.

  @inproceedings{info3-inproceedings-2008-317, abstract = {Wireless Mesh Networks (WMNs) are gaining an increasingly important role in next generation wireless networks. Due to their advantages over other wireless and wired networks, WMNs are undergoing rapid progress and are supposed to deliver wireless services for a large variety of applications. Especially real-time applications such as voice over IP make high demands on wireless mesh networks. A small change of the Quality-of-Service (QoS) metrics like packet loss, delay, and jitter have a significant impact on the Quality-of-Experience (QoE), a subjective measure from the user perspective of the overall value of the provided service or application. In this paper, we present a dynamic bandwidth control mechanism which measures the current situation in the network and adapts the bandwidth in order to ensure a high QoE level. The mechanism is implemented in a Wireless LAN mesh testbed and the results show that real-time applications are successfully protected from disturbing best effort traffic flows.}, address = {Karlskrona, Sweden}, author = {Pries, Rastin and Hock, David and Bayer, Nico and Siebert, Matthias and Staehle, Dirk and Rakocevic, Veselin and Xu, Bangnan and Tran-Gia, Phuoc}, booktitle = {18th ITC Specialist Seminar on Quality of Experience}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Dynamic Bandwidth Control in Wireless Mesh Networks: A Quality of Experience based Approach}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-317 %A Pries, Rastin %A Hock, David %A Bayer, Nico %A Siebert, Matthias %A Staehle, Dirk %A Rakocevic, Veselin %A Xu, Bangnan %A Tran-Gia, Phuoc %B 18th ITC Specialist Seminar on Quality of Experience %C Karlskrona, Sweden %D 2008 %T Dynamic Bandwidth Control in Wireless Mesh Networks: A Quality of Experience based Approach %X Wireless Mesh Networks (WMNs) are gaining an increasingly important role in next generation wireless networks. Due to their advantages over other wireless and wired networks, WMNs are undergoing rapid progress and are supposed to deliver wireless services for a large variety of applications. Especially real-time applications such as voice over IP make high demands on wireless mesh networks. A small change of the Quality-of-Service (QoS) metrics like packet loss, delay, and jitter have a significant impact on the Quality-of-Experience (QoE), a subjective measure from the user perspective of the overall value of the provided service or application. In this paper, we present a dynamic bandwidth control mechanism which measures the current situation in the network and adapts the bandwidth in order to ensure a high QoE level. The mechanism is implemented in a Wireless LAN mesh testbed and the results show that real-time applications are successfully protected from disturbing best effort traffic flows.
• VoIP Service Performance Optimization in Pre-IEEE 802.11s Wireless Mesh Networks. Bayer, Nico; Cavalcanti de Castro, Marcel; Dely, Peter; Kassler, Andreas; Koucheryavy, Yevgeni; Mitoraj, Piotr; Staehle, Dirk. In IEEE ICCSC 2008. Shanghai, China, 2008.
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  @inproceedings{info3-inproceedings-2008-332, address = {Shanghai, China}, author = {Bayer, Nico and Cavalcanti de Castro, Marcel and Dely, Peter and Kassler, Andreas and Koucheryavy, Yevgeni and Mitoraj, Piotr and Staehle, Dirk}, booktitle = {IEEE ICCSC 2008}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {VoIP Service Performance Optimization in Pre-IEEE 802.11s Wireless Mesh Networks}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-332 %A Bayer, Nico %A Cavalcanti de Castro, Marcel %A Dely, Peter %A Kassler, Andreas %A Koucheryavy, Yevgeni %A Mitoraj, Piotr %A Staehle, Dirk %B IEEE ICCSC 2008 %C Shanghai, China %D 2008 %T VoIP Service Performance Optimization in Pre-IEEE 802.11s Wireless Mesh Networks
• A Cross-Layer Approach for Enabling Low Duty Cycled ZigBee Mesh Sensor Networks. Staehle, Barbara; Hoßfeld, Tobias; Vicari, Norbert; Kuhnert, Matthias. In International Symposium on Wireless Pervasive Computing 2008. Santorini, Greece, 2008.
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  In this paper large scale multihop sensor networks are established as non-beacon enabled ZigBee mesh networks. The lifetime of the network is increased by putting nodes to sleep and to wakeup state autonomously. To enable a reliable system with sensor nodes sleeping in an asynchronous manner, we propose a cross-layer sleep scheduling solution coupled with ZigBee’s proposed AODV routing. It consists of two parts: a) Neighbor Aware Communication (NAC) and b) Adaptive Resynchronization (AR). NAC avoids sending packets to sleeping nodes while AR allows the sensor nodes to adapt their sleeping schedule to their neighbors’ duty cycles. ns-2-simulations show that the performance of such a cross-layer optimized system in terms of end-to-end delay and packet delivery ratio is comparable to the benchmark case of synchronized sleep schedules.

  @inproceedings{info3-inproceedings-2008-305, abstract = {In this paper large scale multihop sensor networks are established as non-beacon enabled ZigBee mesh networks. The lifetime of the network is increased by putting nodes to sleep and to wakeup state autonomously. To enable a reliable system with sensor nodes sleeping in an asynchronous manner, we propose a cross-layer sleep scheduling solution coupled with ZigBee’s proposed AODV routing. It consists of two parts: a) Neighbor Aware Communication (NAC) and b) Adaptive Resynchronization (AR). NAC avoids sending packets to sleeping nodes while AR allows the sensor nodes to adapt their sleeping schedule to their neighbors’ duty cycles. ns-2-simulations show that the performance of such a cross-layer optimized system in terms of end-to-end delay and packet delivery ratio is comparable to the benchmark case of synchronized sleep schedules.}, address = {Santorini, Greece}, author = {Staehle, Barbara and Hoßfeld, Tobias and Vicari, Norbert and Kuhnert, Matthias}, booktitle = {International Symposium on Wireless Pervasive Computing 2008}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {A Cross-Layer Approach for Enabling Low Duty Cycled ZigBee Mesh Sensor Networks}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-305 %A Staehle, Barbara %A Hoßfeld, Tobias %A Vicari, Norbert %A Kuhnert, Matthias %B International Symposium on Wireless Pervasive Computing 2008 %C Santorini, Greece %D 2008 %T A Cross-Layer Approach for Enabling Low Duty Cycled ZigBee Mesh Sensor Networks %X In this paper large scale multihop sensor networks are established as non-beacon enabled ZigBee mesh networks. The lifetime of the network is increased by putting nodes to sleep and to wakeup state autonomously. To enable a reliable system with sensor nodes sleeping in an asynchronous manner, we propose a cross-layer sleep scheduling solution coupled with ZigBee’s proposed AODV routing. It consists of two parts: a) Neighbor Aware Communication (NAC) and b) Adaptive Resynchronization (AR). NAC avoids sending packets to sleeping nodes while AR allows the sensor nodes to adapt their sleeping schedule to their neighbors’ duty cycles. ns-2-simulations show that the performance of such a cross-layer optimized system in terms of end-to-end delay and packet delivery ratio is comparable to the benchmark case of synchronized sleep schedules.
• VoIP performance in MeshBed - a Wireless Mesh Network Testbed. Bayer, Nico; Hock, David; Roos, Andreas; Siebert, Matthias; Xu, Bangnan; Rakocevic, Veselin; Habermann, Joachim. In In Proceedings of the 67th IEEE Vehicular Technology Conference (VTC) Spring 2008. Marina Bay, Singapore, 2008.
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  @inproceedings{info3-inproceedings-2008-345, address = {Marina Bay, Singapore}, author = {Bayer, Nico and Hock, David and Roos, Andreas and Siebert, Matthias and Xu, Bangnan and Rakocevic, Veselin and Habermann, Joachim}, booktitle = {In Proceedings of the 67th IEEE Vehicular Technology Conference (VTC) Spring 2008}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {VoIP performance in MeshBed - a Wireless Mesh Network Testbed}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-345 %A Bayer, Nico %A Hock, David %A Roos, Andreas %A Siebert, Matthias %A Xu, Bangnan %A Rakocevic, Veselin %A Habermann, Joachim %B In Proceedings of the 67th IEEE Vehicular Technology Conference (VTC) Spring 2008 %C Marina Bay, Singapore %D 2008 %T VoIP performance in MeshBed - a Wireless Mesh Network Testbed
• Minimizing Installation Costs of Survivable DWDM-Mesh Networks: A Heuristic Approach. Duelli, Michael; Pluntke, Christopher; Menth, Michael. In 4th Euro-NGI Conference on Next Generation Internet Networks (NGI 2008), pp. 15–22. Krakow, Poland, 2008.
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  The cost function for the capacity of optical links follows a step function. That means, the support of one more lightpath might require a costly upgrade of an optical cross connect (OXC), but then additional lightpaths can be supported at almost no further cost. This should be considered when lightpaths are routed through an optical network. In this paper we optimize the routing of the lightpaths to minimize the costs for the required optical equipment. We consider this problem for the failure-free case only and for survivable networks using dedicated path protection. We formulate the problems by integer linear programs (ILPs). In addition, we propose heuristics to solve the problem since solving ILPs is computationally expensive and not feasible for large problem instances. We show that our heuristics lead to good results within a fraction of time compared to ILP solvers.

  @inproceedings{info3-inproceedings-2008-311, abstract = {The cost function for the capacity of optical links follows a step function. That means, the support of one more lightpath might require a costly upgrade of an optical cross connect (OXC), but then additional lightpaths can be supported at almost no further cost. This should be considered when lightpaths are routed through an optical network. In this paper we optimize the routing of the lightpaths to minimize the costs for the required optical equipment. We consider this problem for the failure-free case only and for survivable networks using dedicated path protection. We formulate the problems by integer linear programs (ILPs). In addition, we propose heuristics to solve the problem since solving ILPs is computationally expensive and not feasible for large problem instances. We show that our heuristics lead to good results within a fraction of time compared to ILP solvers.}, address = {Krakow, Poland}, author = {Duelli, Michael and Pluntke, Christopher and Menth, Michael}, booktitle = {4th Euro-NGI Conference on Next Generation Internet Networks (NGI 2008)}, keywords = {100get}, month = {04}, pages = {15–22}, title = {Minimizing Installation Costs of Survivable DWDM-Mesh Networks: A Heuristic Approach}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-311 %A Duelli, Michael %A Pluntke, Christopher %A Menth, Michael %B 4th Euro-NGI Conference on Next Generation Internet Networks (NGI 2008) %C Krakow, Poland %D 2008 %P 15--22 %T Minimizing Installation Costs of Survivable DWDM-Mesh Networks: A Heuristic Approach %X The cost function for the capacity of optical links follows a step function. That means, the support of one more lightpath might require a costly upgrade of an optical cross connect (OXC), but then additional lightpaths can be supported at almost no further cost. This should be considered when lightpaths are routed through an optical network. In this paper we optimize the routing of the lightpaths to minimize the costs for the required optical equipment. We consider this problem for the failure-free case only and for survivable networks using dedicated path protection. We formulate the problems by integer linear programs (ILPs). In addition, we propose heuristics to solve the problem since solving ILPs is computationally expensive and not feasible for large problem instances. We show that our heuristics lead to good results within a fraction of time compared to ILP solvers.
• Three Methods for Optimizing Single-Shortest Path Routing. Dzida, Mateusz; Zagozdzon, Michał; Zotkiewicz, Mateusz; Pióro, Michał; Pettersson, Mats Petter; Duelli, Michael; Menth, Michael. In 4th Euro-NGI Conference on Next Generation Internet Networks (NGI 2008). Krakow, Poland, 2008.
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  Intra-domain routing in IP networks is based on the shortest path principle by assigning administrative weights (costs) to links. The resulting least-cost paths determine routes between pairs of routers. If several such equal-cost paths exist between a pair of routers, it may not be clear which of them is actually used to route traffic. This makes it difficult to predict the network traffic flow distribution. Therefore, the selected link costs should assure uniqueness of the shortest paths. On top of that, the link costs can be optimized with respect to some traffic objective. The resulting optimization problem, referred to as SSPP, turns out to be N P-hard. SSPP can be formulated as a mixed-integer programming problem and, as such, solved with branch-and-bound (B&B). In this paper, we consider three methods for SSPP. Two of them are exact methods based on B&B, namely branch-and-cut and constraint programming. Since the exact solutions of SSPP may require excessive computation time and may not always be effective when applied to practical networks, we also study a fast heuristic method. Finally, in a numerical study, we compare the effectiveness of the three approaches.

  @inproceedings{info3-inproceedings-2008-310, abstract = {Intra-domain routing in IP networks is based on the shortest path principle by assigning administrative weights (costs) to links. The resulting least-cost paths determine routes between pairs of routers. If several such equal-cost paths exist between a pair of routers, it may not be clear which of them is actually used to route traffic. This makes it difficult to predict the network traffic flow distribution. Therefore, the selected link costs should assure uniqueness of the shortest paths. On top of that, the link costs can be optimized with respect to some traffic objective. The resulting optimization problem, referred to as SSPP, turns out to be N P-hard. SSPP can be formulated as a mixed-integer programming problem and, as such, solved with branch-and-bound (B&B). In this paper, we consider three methods for SSPP. Two of them are exact methods based on B&B, namely branch-and-cut and constraint programming. Since the exact solutions of SSPP may require excessive computation time and may not always be effective when applied to practical networks, we also study a fast heuristic method. Finally, in a numerical study, we compare the effectiveness of the three approaches.}, address = {Krakow, Poland}, author = {Dzida, Mateusz and Zagozdzon, Michał and Zotkiewicz, Mateusz and Pióro, Michał and Pettersson, Mats Petter and Duelli, Michael and Menth, Michael}, booktitle = {4th Euro-NGI Conference on Next Generation Internet Networks (NGI 2008)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Three Methods for Optimizing Single-Shortest Path Routing}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-310 %A Dzida, Mateusz %A Zagozdzon, Michał %A Zotkiewicz, Mateusz %A Pióro, Michał %A Pettersson, Mats Petter %A Duelli, Michael %A Menth, Michael %B 4th Euro-NGI Conference on Next Generation Internet Networks (NGI 2008) %C Krakow, Poland %D 2008 %T Three Methods for Optimizing Single-Shortest Path Routing %X Intra-domain routing in IP networks is based on the shortest path principle by assigning administrative weights (costs) to links. The resulting least-cost paths determine routes between pairs of routers. If several such equal-cost paths exist between a pair of routers, it may not be clear which of them is actually used to route traffic. This makes it difficult to predict the network traffic flow distribution. Therefore, the selected link costs should assure uniqueness of the shortest paths. On top of that, the link costs can be optimized with respect to some traffic objective. The resulting optimization problem, referred to as SSPP, turns out to be N P-hard. SSPP can be formulated as a mixed-integer programming problem and, as such, solved with branch-and-bound (B&B). In this paper, we consider three methods for SSPP. Two of them are exact methods based on B&B, namely branch-and-cut and constraint programming. Since the exact solutions of SSPP may require excessive computation time and may not always be effective when applied to practical networks, we also study a fast heuristic method. Finally, in a numerical study, we compare the effectiveness of the three approaches.
• Performance Evaluation of IP over Cost-Optimized Optical Multilayer Networks with SRLGs. Duelli, Michael; Hartmann, Matthias; Menth, Michael; Hülsermann, Ralf; Düser, Michael. In 9. ITG-Fachtagung Photonische Netze, pp. 21–29. Leipzig, Germany, 2008.
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  The design of optical transport and IP networks is investigated with respect to the effect on overall network perfor mance when the two aspects are combined in the same network architecture. The focus is on the identification of advantages in the joint design of IP and transport networks, as well as on the shortcomings and network bottlenecks which may result from sub-optimal design. The impact of different IP routing strategies (shortest path, equal-cost multipath) on the network utilization is quantified, and potential sources for overload in the IP domain are determined. Simulations were carried out to systematically assess technical metrics like link utilization and economic parameters such as cost for a 50-node transport network with line rates up to 40 Gbit/s. The impact of fiber cuts was taken into account, leading to multiple logical IP links to fail simultaneously, i.e. shared risk link groups (SRLGs), and triggering massive IP rerouting. Applying the results allows to identify bottlenecks in the design, and to devise mechanisms which allow cost-optimal network design of future IP and optical transport networks.

  @inproceedings{info3-inproceedings-2008-312, abstract = {The design of optical transport and IP networks is investigated with respect to the effect on overall network perfor mance when the two aspects are combined in the same network architecture. The focus is on the identification of advantages in the joint design of IP and transport networks, as well as on the shortcomings and network bottlenecks which may result from sub-optimal design. The impact of different IP routing strategies (shortest path, equal-cost multipath) on the network utilization is quantified, and potential sources for overload in the IP domain are determined. Simulations were carried out to systematically assess technical metrics like link utilization and economic parameters such as cost for a 50-node transport network with line rates up to 40 Gbit/s. The impact of fiber cuts was taken into account, leading to multiple logical IP links to fail simultaneously, i.e. shared risk link groups (SRLGs), and triggering massive IP rerouting. Applying the results allows to identify bottlenecks in the design, and to devise mechanisms which allow cost-optimal network design of future IP and optical transport networks.}, address = {Leipzig, Germany}, author = {Duelli, Michael and Hartmann, Matthias and Menth, Michael and Hülsermann, Ralf and Düser, Michael}, booktitle = {9. ITG-Fachtagung Photonische Netze}, keywords = {100get}, month = {04}, pages = {21–29}, title = {Performance Evaluation of IP over Cost-Optimized Optical Multilayer Networks with SRLGs}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-312 %A Duelli, Michael %A Hartmann, Matthias %A Menth, Michael %A Hülsermann, Ralf %A Düser, Michael %B 9. ITG-Fachtagung Photonische Netze %C Leipzig, Germany %D 2008 %P 21--29 %T Performance Evaluation of IP over Cost-Optimized Optical Multilayer Networks with SRLGs %X The design of optical transport and IP networks is investigated with respect to the effect on overall network perfor mance when the two aspects are combined in the same network architecture. The focus is on the identification of advantages in the joint design of IP and transport networks, as well as on the shortcomings and network bottlenecks which may result from sub-optimal design. The impact of different IP routing strategies (shortest path, equal-cost multipath) on the network utilization is quantified, and potential sources for overload in the IP domain are determined. Simulations were carried out to systematically assess technical metrics like link utilization and economic parameters such as cost for a 50-node transport network with line rates up to 40 Gbit/s. The impact of fiber cuts was taken into account, leading to multiple logical IP links to fail simultaneously, i.e. shared risk link groups (SRLGs), and triggering massive IP rerouting. Applying the results allows to identify bottlenecks in the design, and to devise mechanisms which allow cost-optimal network design of future IP and optical transport networks.
• Relaxed Multiple Routing Configurations for IP Fast Reroute. Cicic, Tarik; Fosselie Hansen, Audun; Kvalbein, Amund; Hartmann, Matthias; Martin, Rüdiger; Menth, Michael. In IEEE/IFIP Network Operations and Management Symposium. Salvador, Bahia, Brazil, 2008.
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  Multi-topology routing is an increasingly popular IP network management concept that allows transport of different traffic types over disjoint network paths. The concept is of particular interest for implementation of IP fast reroute (IP FRR). First, it can support guaranteed, instantaneous recovery from any link or node failure. Second, different failures result in routing over different network topologies, which augments the parameter space for load distribution optimizations. Multiple Routing Configurations (MRC) is the state-of-the-art IP FRR scheme based on multi-topology routing today. In this paper we present a new, enhanced IP FRR scheme which we call 'relaxed MRC' (rMRC). rMRC simplifies the topology construction and increases the routing flexibility in each topology. According to our experimental evaluation, rMRC has several benefits compared to MRC. The number of backup topologies required to provide protection against the same set of failures is reduced, hence reducing state in routers. In addition, the backup paths are shorter, and the link utilization is significantly better.

  @inproceedings{info3-inproceedings-2008-302, abstract = {Multi-topology routing is an increasingly popular IP network management concept that allows transport of different traffic types over disjoint network paths. The concept is of particular interest for implementation of IP fast reroute (IP FRR). First, it can support guaranteed, instantaneous recovery from any link or node failure. Second, different failures result in routing over different network topologies, which augments the parameter space for load distribution optimizations. Multiple Routing Configurations (MRC) is the state-of-the-art IP FRR scheme based on multi-topology routing today. In this paper we present a new, enhanced IP FRR scheme which we call 'relaxed MRC' (rMRC). rMRC simplifies the topology construction and increases the routing flexibility in each topology. According to our experimental evaluation, rMRC has several benefits compared to MRC. The number of backup topologies required to provide protection against the same set of failures is reduced, hence reducing state in routers. In addition, the backup paths are shorter, and the link utilization is significantly better.}, address = {Salvador, Bahia, Brazil}, author = {Cicic, Tarik and Fosselie Hansen, Audun and Kvalbein, Amund and Hartmann, Matthias and Martin, Rüdiger and Menth, Michael}, booktitle = {IEEE/IFIP Network Operations and Management Symposium}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Relaxed Multiple Routing Configurations for IP Fast Reroute}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-302 %A Cicic, Tarik %A Fosselie Hansen, Audun %A Kvalbein, Amund %A Hartmann, Matthias %A Martin, Rüdiger %A Menth, Michael %B IEEE/IFIP Network Operations and Management Symposium %C Salvador, Bahia, Brazil %D 2008 %T Relaxed Multiple Routing Configurations for IP Fast Reroute %X Multi-topology routing is an increasingly popular IP network management concept that allows transport of different traffic types over disjoint network paths. The concept is of particular interest for implementation of IP fast reroute (IP FRR). First, it can support guaranteed, instantaneous recovery from any link or node failure. Second, different failures result in routing over different network topologies, which augments the parameter space for load distribution optimizations. Multiple Routing Configurations (MRC) is the state-of-the-art IP FRR scheme based on multi-topology routing today. In this paper we present a new, enhanced IP FRR scheme which we call 'relaxed MRC' (rMRC). rMRC simplifies the topology construction and increases the routing flexibility in each topology. According to our experimental evaluation, rMRC has several benefits compared to MRC. The number of backup topologies required to provide protection against the same set of failures is reduced, hence reducing state in routers. In addition, the backup paths are shorter, and the link utilization is significantly better.
• Comparison of Marking Algorithms for PCN-Based Admission Control. Menth, Michael; Lehrieder, Frank. In GI/ITG Conference on Measurement, Modeling, and Evaluation of Computer and Communication Systems (MMB’2008). Dortmund, Germany, 2008.
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  @inproceedings{info3-inproceedings-2008-319, address = {Dortmund, Germany}, author = {Menth, Michael and Lehrieder, Frank}, booktitle = {GI/ITG Conference on Measurement, Modeling, and Evaluation of Computer and Communication Systems (MMB'2008)}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Comparison of Marking Algorithms for PCN-Based Admission Control}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-319 %A Menth, Michael %A Lehrieder, Frank %B GI/ITG Conference on Measurement, Modeling, and Evaluation of Computer and Communication Systems (MMB'2008) %C Dortmund, Germany %D 2008 %T Comparison of Marking Algorithms for PCN-Based Admission Control
• A Seamless Vertical Handover Approach. Pries, Rastin; Staehle, Dirk; Tran-Gia, Phuoc; Gutbrod, Thorsten. In Wireless and Mobility 2008, LNCS 5122. Barcelona, Spain, 2008.
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  @inproceedings{info3-inproceedings-2008-326, address = {Barcelona, Spain}, author = {Pries, Rastin and Staehle, Dirk and Tran-Gia, Phuoc and Gutbrod, Thorsten}, booktitle = {Wireless and Mobility 2008, LNCS 5122}, keywords = {sys:hidden:inproceedings}, month = {01}, title = {A Seamless Vertical Handover Approach}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-326 %A Pries, Rastin %A Staehle, Dirk %A Tran-Gia, Phuoc %A Gutbrod, Thorsten %B Wireless and Mobility 2008, LNCS 5122 %C Barcelona, Spain %D 2008 %T A Seamless Vertical Handover Approach
• Speech Quality Aware Admission Control for fixed IEEE 802.16 Wireless MAN. Michael Bohnert, Thomas; Staehle, Dirk; Kuo, Geng-Sheng; Koucheryavy, Yevgeni; Monteiro, Edmundo. In IEEE ICC. Beijing, China, 2008.
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  @inproceedings{info3-inproceedings-2008-324, address = {Beijing, China}, author = {Michael Bohnert, Thomas and Staehle, Dirk and Kuo, Geng-Sheng and Koucheryavy, Yevgeni and Monteiro, Edmundo}, booktitle = {IEEE ICC}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Speech Quality Aware Admission Control for fixed IEEE 802.16 Wireless MAN}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-324 %A Michael Bohnert, Thomas %A Staehle, Dirk %A Kuo, Geng-Sheng %A Koucheryavy, Yevgeni %A Monteiro, Edmundo %B IEEE ICC %C Beijing, China %D 2008 %T Speech Quality Aware Admission Control for fixed IEEE 802.16 Wireless MAN
• Performance Comparison and Evaluation of AODV, OLSR and SBR in Mobile Ad-Hoc Networks. Klein, Alexander. In International Symposium on Wireless Pervasive Computing (ISWPC), p. 5. Santorini, Greece, 2008.
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  @inproceedings{info3-inproceedings-2008-306, address = {Santorini, Greece}, author = {Klein, Alexander}, booktitle = {International Symposium on Wireless Pervasive Computing (ISWPC)}, keywords = {sys:hidden:inproceedings}, month = {05}, pages = 5, title = {Performance Comparison and Evaluation of AODV, OLSR and SBR in Mobile Ad-Hoc Networks}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-306 %A Klein, Alexander %B International Symposium on Wireless Pervasive Computing (ISWPC) %C Santorini, Greece %D 2008 %P 5 %T Performance Comparison and Evaluation of AODV, OLSR and SBR in Mobile Ad-Hoc Networks
• A New Approach for Managing Traffic of Overlay Applications of the SmoothIT Project. Fernandez-Palacios Gimenez, Juan Pedro; Angeles Callejo Rodriguez, Maria; Hasan, Hasan; Hoßfeld, Tobias; Staehle, Dirk; Despotovic, Zoran; Kellerer, Wolfgang; Pussep, Konstantin; Papafili, Ioanna; Stamoulis, George D.; Stiller, Burkhard. In 2nd International Conference on Autonomous Infrastructure, Management and Security (AIMS 2008). Bremen, Germany, 2008.
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  Overlay networks emerged in the last decade and generate now a large portion of the Internet traffic [Internet07]. Even though they were initially associated exclusively with copyright infringements and, thus, provoked considerable public odium, their good properties supersede and the overlay networking technology is here to stay. On one hand, overlay networks can provide specific applications without being supported by current underlay network, e.g., multicast. On the other hand, the client-server model does not scale in different respects, and many content distributors find it more efficient to deliver their content using overlay networks. For example, free Linux distributions (e.g., Red Hat’s Fedora or Debian) are distributed via BitTorrent. Furthermore, the Internet traffic stemming from overlay-based applications, e.g., Peer-to-Peer (P2P) applications, increases rapidly with the increase of available bandwidth of end-nodes. Therefore, a slow paradigm shift from centrally offered services to services offered by end-nodes is in progress. For today’s Telecommunication Service Providers (telcos) and Internet Service Providers (ISP) the key issue arising is how to control and manage network traffic stemming from such overlaybased applications. As the structure of overlays determines traffic flows in ISP networks, it is highly efficient for an ISP to influence the overlay configuration based on information on their structure. Thus, the management of overlays aims (a) to maximize the benefit for multiple operators/ISPs involved and (b) to increase the capability to withstand faults and balancing the network load. Traditional traffic engineering methodologies are insufficient to satisfy simultaneously the provider’s goal to maximize network usage and the user’s goal to maximize his utility, since most of current overlay networks are deployed oblivious of the underlying physical network [Awduche99]. E.g., traffic between two nodes in the Telefonica network in Madrid can go via Tokyo, incurring large and unnecessary costs. This is why network operators show a strong interest in influencing overlay network operations and shaping the overlay traffic as to comply with their needs. Within that context, SmoothIT proposes a new traffic management mechanism termed Economic Traffic Management (ETM), which provides for an incentivecompatibility in those interactions foreseen between overlay applications and the underlying ISP networks in order to gain the following measurable impacts: 1. Cost saving for ISPs: lower operation costs, due to ETM-based traffic engineering, lower interconnection costs, since traffic can be kept inside an ISP’s domain, and lower capacity extension cost, since capacity requirements can be forecasted with much higher accuracy. 2. Lower prices for end-users, due to competitive pricing by the ISP, which are enabled by new ETM mechanisms. 3. Better Quality-of-Service (QoS) for overlay-based applications across ISP domains, due to the usage of ETM-based traffic engineering. This leads to an improved media consumption experience for end users.

  @inproceedings{info3-inproceedings-2008-321, abstract = {Overlay networks emerged in the last decade and generate now a large portion of the Internet traffic [Internet07]. Even though they were initially associated exclusively with copyright infringements and, thus, provoked considerable public odium, their good properties supersede and the overlay networking technology is here to stay. On one hand, overlay networks can provide specific applications without being supported by current underlay network, e.g., multicast. On the other hand, the client-server model does not scale in different respects, and many content distributors find it more efficient to deliver their content using overlay networks. For example, free Linux distributions (e.g., Red Hat’s Fedora or Debian) are distributed via BitTorrent. Furthermore, the Internet traffic stemming from overlay-based applications, e.g., Peer-to-Peer (P2P) applications, increases rapidly with the increase of available bandwidth of end-nodes. Therefore, a slow paradigm shift from centrally offered services to services offered by end-nodes is in progress. For today’s Telecommunication Service Providers (telcos) and Internet Service Providers (ISP) the key issue arising is how to control and manage network traffic stemming from such overlaybased applications. As the structure of overlays determines traffic flows in ISP networks, it is highly efficient for an ISP to influence the overlay configuration based on information on their structure. Thus, the management of overlays aims (a) to maximize the benefit for multiple operators/ISPs involved and (b) to increase the capability to withstand faults and balancing the network load. Traditional traffic engineering methodologies are insufficient to satisfy simultaneously the provider’s goal to maximize network usage and the user’s goal to maximize his utility, since most of current overlay networks are deployed oblivious of the underlying physical network [Awduche99]. E.g., traffic between two nodes in the Telefonica network in Madrid can go via Tokyo, incurring large and unnecessary costs. This is why network operators show a strong interest in influencing overlay network operations and shaping the overlay traffic as to comply with their needs. Within that context, SmoothIT proposes a new traffic management mechanism termed Economic Traffic Management (ETM), which provides for an incentivecompatibility in those interactions foreseen between overlay applications and the underlying ISP networks in order to gain the following measurable impacts: 1. Cost saving for ISPs: lower operation costs, due to ETM-based traffic engineering, lower interconnection costs, since traffic can be kept inside an ISP’s domain, and lower capacity extension cost, since capacity requirements can be forecasted with much higher accuracy. 2. Lower prices for end-users, due to competitive pricing by the ISP, which are enabled by new ETM mechanisms. 3. Better Quality-of-Service (QoS) for overlay-based applications across ISP domains, due to the usage of ETM-based traffic engineering. This leads to an improved media consumption experience for end users.}, address = {Bremen, Germany}, author = {Fernandez-Palacios Gimenez, Juan Pedro and Angeles Callejo Rodriguez, Maria and Hasan, Hasan and Hoßfeld, Tobias and Staehle, Dirk and Despotovic, Zoran and Kellerer, Wolfgang and Pussep, Konstantin and Papafili, Ioanna and Stamoulis, George D. and Stiller, Burkhard}, booktitle = {2nd International Conference on Autonomous Infrastructure, Management and Security (AIMS 2008)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {A New Approach for Managing Traffic of Overlay Applications of the SmoothIT Project}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-321 %A Fernandez-Palacios Gimenez, Juan Pedro %A Angeles Callejo Rodriguez, Maria %A Hasan, Hasan %A Hoßfeld, Tobias %A Staehle, Dirk %A Despotovic, Zoran %A Kellerer, Wolfgang %A Pussep, Konstantin %A Papafili, Ioanna %A Stamoulis, George D. %A Stiller, Burkhard %B 2nd International Conference on Autonomous Infrastructure, Management and Security (AIMS 2008) %C Bremen, Germany %D 2008 %T A New Approach for Managing Traffic of Overlay Applications of the SmoothIT Project %X Overlay networks emerged in the last decade and generate now a large portion of the Internet traffic [Internet07]. Even though they were initially associated exclusively with copyright infringements and, thus, provoked considerable public odium, their good properties supersede and the overlay networking technology is here to stay. On one hand, overlay networks can provide specific applications without being supported by current underlay network, e.g., multicast. On the other hand, the client-server model does not scale in different respects, and many content distributors find it more efficient to deliver their content using overlay networks. For example, free Linux distributions (e.g., Red Hat’s Fedora or Debian) are distributed via BitTorrent. Furthermore, the Internet traffic stemming from overlay-based applications, e.g., Peer-to-Peer (P2P) applications, increases rapidly with the increase of available bandwidth of end-nodes. Therefore, a slow paradigm shift from centrally offered services to services offered by end-nodes is in progress. For today’s Telecommunication Service Providers (telcos) and Internet Service Providers (ISP) the key issue arising is how to control and manage network traffic stemming from such overlaybased applications. As the structure of overlays determines traffic flows in ISP networks, it is highly efficient for an ISP to influence the overlay configuration based on information on their structure. Thus, the management of overlays aims (a) to maximize the benefit for multiple operators/ISPs involved and (b) to increase the capability to withstand faults and balancing the network load. Traditional traffic engineering methodologies are insufficient to satisfy simultaneously the provider’s goal to maximize network usage and the user’s goal to maximize his utility, since most of current overlay networks are deployed oblivious of the underlying physical network [Awduche99]. E.g., traffic between two nodes in the Telefonica network in Madrid can go via Tokyo, incurring large and unnecessary costs. This is why network operators show a strong interest in influencing overlay network operations and shaping the overlay traffic as to comply with their needs. Within that context, SmoothIT proposes a new traffic management mechanism termed Economic Traffic Management (ETM), which provides for an incentivecompatibility in those interactions foreseen between overlay applications and the underlying ISP networks in order to gain the following measurable impacts: 1. Cost saving for ISPs: lower operation costs, due to ETM-based traffic engineering, lower interconnection costs, since traffic can be kept inside an ISP’s domain, and lower capacity extension cost, since capacity requirements can be forecasted with much higher accuracy. 2. Lower prices for end-users, due to competitive pricing by the ISP, which are enabled by new ETM mechanisms. 3. Better Quality-of-Service (QoS) for overlay-based applications across ISP domains, due to the usage of ETM-based traffic engineering. This leads to an improved media consumption experience for end users.
• Testing the IQX Hypothesis for Exponential Interdependency between QoS and QoE of Voice Codecs iLBC and G.711. Hoßfeld, Tobias; Hock, David; Tran-Gia, Phuoc; Tutschku, Kurt; Fiedler, Markus. In 18th ITC Specialist Seminar on Quality of Experience. Karlskrona, Sweden, 2008.
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  @inproceedings{info3-inproceedings-2008-318, address = {Karlskrona, Sweden}, author = {Hoßfeld, Tobias and Hock, David and Tran-Gia, Phuoc and Tutschku, Kurt and Fiedler, Markus}, booktitle = {18th ITC Specialist Seminar on Quality of Experience}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Testing the IQX Hypothesis for Exponential Interdependency between QoS and QoE of Voice Codecs iLBC and G.711}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-318 %A Hoßfeld, Tobias %A Hock, David %A Tran-Gia, Phuoc %A Tutschku, Kurt %A Fiedler, Markus %B 18th ITC Specialist Seminar on Quality of Experience %C Karlskrona, Sweden %D 2008 %T Testing the IQX Hypothesis for Exponential Interdependency between QoS and QoE of Voice Codecs iLBC and G.711
• A Closer Look at the Association Procedure in Low Power 802.15.4 Multihop Sensor Networks. Staehle, Barbara. In 7. GI/ITG KuVS Fachgespräch Drahtlose Sensornetze. Berlin, Germany, 2008.
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  IEEE 802.15.4 proposes the advantage of a standardized low power low data rate communication stack and is thereforealso an option for deploying low power wireless sensor networks (WSNs). Most studies of 802.15.4 based WSNs concentrate on the operational phase and neglected the initial startup phase. Thisb ears however also potentials for energy savings, as the 802.15.4 association procedure has to be executed to make the network operational and is not ptimized for low power networks. In this study, we point out directions how to perform the association in a self organizing and energy saving way.

  @inproceedings{info3-inproceedings-2008-328, abstract = {IEEE 802.15.4 proposes the advantage of a standardized low power low data rate communication stack and is thereforealso an option for deploying low power wireless sensor networks (WSNs). Most studies of 802.15.4 based WSNs concentrate on the operational phase and neglected the initial startup phase. Thisb ears however also potentials for energy savings, as the 802.15.4 association procedure has to be executed to make the network operational and is not ptimized for low power networks. In this study, we point out directions how to perform the association in a self organizing and energy saving way.}, address = {Berlin, Germany}, author = {Staehle, Barbara}, booktitle = {7. GI/ITG KuVS Fachgespräch Drahtlose Sensornetze}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {A Closer Look at the Association Procedure in Low Power 802.15.4 Multihop Sensor Networks}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-328 %A Staehle, Barbara %B 7. GI/ITG KuVS Fachgespräch Drahtlose Sensornetze %C Berlin, Germany %D 2008 %T A Closer Look at the Association Procedure in Low Power 802.15.4 Multihop Sensor Networks %X IEEE 802.15.4 proposes the advantage of a standardized low power low data rate communication stack and is thereforealso an option for deploying low power wireless sensor networks (WSNs). Most studies of 802.15.4 based WSNs concentrate on the operational phase and neglected the initial startup phase. Thisb ears however also potentials for energy savings, as the 802.15.4 association procedure has to be executed to make the network operational and is not ptimized for low power networks. In this study, we point out directions how to perform the association in a self organizing and energy saving way.
• IEEE 802.16 Capacity Enhancement Using an Adaptive TDD Split. Pries, Rastin; Staehle, Dirk; Marsico, Daniel. In IEEE VTC Spring 08. Singapore, 2008.
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  In urban areas, users have become more and more accustomed to the availability of broadband access. However, in rural and suburban areas, it is often too expensive for network providers to serve every user with traditional wired broadband access such as DSL or cable modem. In such areas, WiMAX (worldwide interoperability for microwave access) networks based on the IEEE 802.16 standard are the most promising solution. In this paper, we focus on the performance of the IEEE 802.16 time division duplex (TDD) mode in rural areas with only one cell. When using TDD, the duration of the downlink and uplink subframe can be set individually, which is called adaptive time division duplex (ATDD). However, the ratio between downlink and uplink is normally set to a fixed value. We will show the performance of different fixed downlink/uplink ratios for several traffic models. Furthermore, we propose an algorithm for an adaptive downlink/uplink boundary in dependence on the current traffic load in the cell. The results show an enormous performance gain compared to the fixed settings.

  @inproceedings{info3-inproceedings-2008-304, abstract = {In urban areas, users have become more and more accustomed to the availability of broadband access. However, in rural and suburban areas, it is often too expensive for network providers to serve every user with traditional wired broadband access such as DSL or cable modem. In such areas, WiMAX (worldwide interoperability for microwave access) networks based on the IEEE 802.16 standard are the most promising solution. In this paper, we focus on the performance of the IEEE 802.16 time division duplex (TDD) mode in rural areas with only one cell. When using TDD, the duration of the downlink and uplink subframe can be set individually, which is called adaptive time division duplex (ATDD). However, the ratio between downlink and uplink is normally set to a fixed value. We will show the performance of different fixed downlink/uplink ratios for several traffic models. Furthermore, we propose an algorithm for an adaptive downlink/uplink boundary in dependence on the current traffic load in the cell. The results show an enormous performance gain compared to the fixed settings.}, address = {Singapore}, author = {Pries, Rastin and Staehle, Dirk and Marsico, Daniel}, booktitle = {IEEE VTC Spring 08}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {IEEE 802.16 Capacity Enhancement Using an Adaptive TDD Split}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-304 %A Pries, Rastin %A Staehle, Dirk %A Marsico, Daniel %B IEEE VTC Spring 08 %C Singapore %D 2008 %T IEEE 802.16 Capacity Enhancement Using an Adaptive TDD Split %X In urban areas, users have become more and more accustomed to the availability of broadband access. However, in rural and suburban areas, it is often too expensive for network providers to serve every user with traditional wired broadband access such as DSL or cable modem. In such areas, WiMAX (worldwide interoperability for microwave access) networks based on the IEEE 802.16 standard are the most promising solution. In this paper, we focus on the performance of the IEEE 802.16 time division duplex (TDD) mode in rural areas with only one cell. When using TDD, the duration of the downlink and uplink subframe can be set individually, which is called adaptive time division duplex (ATDD). However, the ratio between downlink and uplink is normally set to a fixed value. We will show the performance of different fixed downlink/uplink ratios for several traffic models. Furthermore, we propose an algorithm for an adaptive downlink/uplink boundary in dependence on the current traffic load in the cell. The results show an enormous performance gain compared to the fixed settings.
• A framework of economic traffic management employing self-organization overlay mechanisms. Oechsner, Simon; Soursos, Sergios; Papafili, Ioanna; Hoßfeld, Tobias; Stamoulis, George D.; Stiller, Burkhard; Angeles Callejo, Maria; Staehle, Dirk. In IWSOS’08. Vienna, Austria, 2008.
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  Applications based on overlays have become very popular, due to the separation they provide and the improvement of perceived QoS by the end-user. Recent studies show that overlays have a significant impact on the traffic management and the expenditures of the underlying network operators. In this paper, we define a framework for Economic Traffic Management (ETM) mechanisms that optimize the traffic impact of overlay applications on ISP and telecommunication operator networks based on the interaction of network operators, overlay providers and users. We first provide a definition and an overview of Self- Organization Mechanisms (SOMs) and ETM for overlays. We then describe a basic framework for the interaction of components of SOMs and ETM, in terms of information and metrics provided, decisions made etc. Finally, we describe in detail how SOMs can be used to support ETM and we illustrate our approach and its implications by means of a specific example.

  @inproceedings{info3-inproceedings-2008-331, abstract = {Applications based on overlays have become very popular, due to the separation they provide and the improvement of perceived QoS by the end-user. Recent studies show that overlays have a significant impact on the traffic management and the expenditures of the underlying network operators. In this paper, we define a framework for Economic Traffic Management (ETM) mechanisms that optimize the traffic impact of overlay applications on ISP and telecommunication operator networks based on the interaction of network operators, overlay providers and users. We first provide a definition and an overview of Self- Organization Mechanisms (SOMs) and ETM for overlays. We then describe a basic framework for the interaction of components of SOMs and ETM, in terms of information and metrics provided, decisions made etc. Finally, we describe in detail how SOMs can be used to support ETM and we illustrate our approach and its implications by means of a specific example.}, address = {Vienna, Austria}, author = {Oechsner, Simon and Soursos, Sergios and Papafili, Ioanna and Hoßfeld, Tobias and Stamoulis, George D. and Stiller, Burkhard and Angeles Callejo, Maria and Staehle, Dirk}, booktitle = {IWSOS'08}, keywords = {sys:hidden:inproceedings}, month = 12, title = {A framework of economic traffic management employing self-organization overlay mechanisms}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-331 %A Oechsner, Simon %A Soursos, Sergios %A Papafili, Ioanna %A Hoßfeld, Tobias %A Stamoulis, George D. %A Stiller, Burkhard %A Angeles Callejo, Maria %A Staehle, Dirk %B IWSOS'08 %C Vienna, Austria %D 2008 %T A framework of economic traffic management employing self-organization overlay mechanisms %X Applications based on overlays have become very popular, due to the separation they provide and the improvement of perceived QoS by the end-user. Recent studies show that overlays have a significant impact on the traffic management and the expenditures of the underlying network operators. In this paper, we define a framework for Economic Traffic Management (ETM) mechanisms that optimize the traffic impact of overlay applications on ISP and telecommunication operator networks based on the interaction of network operators, overlay providers and users. We first provide a definition and an overview of Self- Organization Mechanisms (SOMs) and ETM for overlays. We then describe a basic framework for the interaction of components of SOMs and ETM, in terms of information and metrics provided, decisions made etc. Finally, we describe in detail how SOMs can be used to support ETM and we illustrate our approach and its implications by means of a specific example.
• Performance Modeling of Data Aggregation in Wireless Sensor Networks. Hoßfeld, Tobias; Leibnitz, Kenji. In Invited Paper at the Jointly-organized Symposium of the Institute of Intelligent Information and Communications Technology (IICT) at Konan University and the ORSJ (Operations Research Society of Japan). Kobe, Japan, 2008.
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  @inproceedings{info3-inproceedings-2008-334, address = {Kobe, Japan}, author = {Hoßfeld, Tobias and Leibnitz, Kenji}, booktitle = {Invited Paper at the Jointly-organized Symposium of the Institute of Intelligent Information and Communications Technology (IICT) at Konan University and the ORSJ (Operations Research Society of Japan)}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Performance Modeling of Data Aggregation in Wireless Sensor Networks}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-334 %A Hoßfeld, Tobias %A Leibnitz, Kenji %B Invited Paper at the Jointly-organized Symposium of the Institute of Intelligent Information and Communications Technology (IICT) at Konan University and the ORSJ (Operations Research Society of Japan) %C Kobe, Japan %D 2008 %T Performance Modeling of Data Aggregation in Wireless Sensor Networks
• How to Take Advantage from Correlated Node Movement in Mobile Sensor Networks. Klein, Alexander. In 7. GI/ITG KuVS Fachgespräch, p. 4. Berlin, Germany, 2008.
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  @inproceedings{info3-inproceedings-2008-327, address = {Berlin, Germany}, author = {Klein, Alexander}, booktitle = {7. GI/ITG KuVS Fachgespräch}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = 4, title = {How to Take Advantage from Correlated Node Movement in Mobile Sensor Networks}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-327 %A Klein, Alexander %B 7. GI/ITG KuVS Fachgespräch %C Berlin, Germany %D 2008 %P 4 %T How to Take Advantage from Correlated Node Movement in Mobile Sensor Networks
• On the Trade-off between Efficiency and Congestion in Location-aware Overlay Networks - Example of a Vertical Handover Support System. Zinner, Thomas; Hoßfeld, Tobias; Oechsner, Simon; Tran-Gia, Phuoc. In Eighth International Conference on Peer-to-Peer Computing (P2P 2008). Aachen, Germany, 2008.
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  Introducing location-awareness in overlay networks allows for a higher efficiency of the offered services, e.g., shorter search times or higher throughput. This is especially important for business applications supported by overlays. In this paper, we will illustrate how such an increase in efficiency causes congestion in an otherwise well-dimensioned locality-aware overlay using a Distributed Hash Table (DHT). In particular, we will use a Vertical Handover (VHO) support system using a Pastry substrate as an example. We will describe the occuring congestion problem and identify the underlying reasons. Thus, we describe the basic trade-off between efficiency and load-inequality. Furthermore, we introduce a solution for the specific issue observed, and conduct a performance evaluation identifying the major influence factors and optimization potential for future work.

  @inproceedings{info3-inproceedings-2008-323, abstract = {Introducing location-awareness in overlay networks allows for a higher efficiency of the offered services, e.g., shorter search times or higher throughput. This is especially important for business applications supported by overlays. In this paper, we will illustrate how such an increase in efficiency causes congestion in an otherwise well-dimensioned locality-aware overlay using a Distributed Hash Table (DHT). In particular, we will use a Vertical Handover (VHO) support system using a Pastry substrate as an example. We will describe the occuring congestion problem and identify the underlying reasons. Thus, we describe the basic trade-off between efficiency and load-inequality. Furthermore, we introduce a solution for the specific issue observed, and conduct a performance evaluation identifying the major influence factors and optimization potential for future work.}, address = {Aachen, Germany}, author = {Zinner, Thomas and Hoßfeld, Tobias and Oechsner, Simon and Tran-Gia, Phuoc}, booktitle = {Eighth International Conference on Peer-to-Peer Computing (P2P 2008)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {On the Trade-off between Efficiency and Congestion in Location-aware Overlay Networks - Example of a Vertical Handover Support System}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-323 %A Zinner, Thomas %A Hoßfeld, Tobias %A Oechsner, Simon %A Tran-Gia, Phuoc %B Eighth International Conference on Peer-to-Peer Computing (P2P 2008) %C Aachen, Germany %D 2008 %T On the Trade-off between Efficiency and Congestion in Location-aware Overlay Networks - Example of a Vertical Handover Support System %X Introducing location-awareness in overlay networks allows for a higher efficiency of the offered services, e.g., shorter search times or higher throughput. This is especially important for business applications supported by overlays. In this paper, we will illustrate how such an increase in efficiency causes congestion in an otherwise well-dimensioned locality-aware overlay using a Distributed Hash Table (DHT). In particular, we will use a Vertical Handover (VHO) support system using a Pastry substrate as an example. We will describe the occuring congestion problem and identify the underlying reasons. Thus, we describe the basic trade-off between efficiency and load-inequality. Furthermore, we introduce a solution for the specific issue observed, and conduct a performance evaluation identifying the major influence factors and optimization potential for future work.
• Performance Evaluation of the Information Sink in a Multi-Probe Statistical Anomaly Detection System. Zinner, Thomas; Staehle, Dirk; Tran-Gia, Phuoc; Mäder, Andreas; Tutschku, Kurt. In Australasian Telecommunication Networks and Applications Conference 2008. Adelaide, 2008.
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  @inproceedings{info3-inproceedings-2008-329, address = {Adelaide}, author = {Zinner, Thomas and Staehle, Dirk and Tran-Gia, Phuoc and Mäder, Andreas and Tutschku, Kurt}, booktitle = {Australasian Telecommunication Networks and Applications Conference 2008}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Performance Evaluation of the Information Sink in a Multi-Probe Statistical Anomaly Detection System}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-329 %A Zinner, Thomas %A Staehle, Dirk %A Tran-Gia, Phuoc %A Mäder, Andreas %A Tutschku, Kurt %B Australasian Telecommunication Networks and Applications Conference 2008 %C Adelaide %D 2008 %T Performance Evaluation of the Information Sink in a Multi-Probe Statistical Anomaly Detection System
• Modeling of P2P-based Video Streaming. Stiller, Burkhard; Hoßfeld, Tobias. In Joint EC-GIN, EMANICS, and SmoothIT Workshop Economic Traffic Management. Zurich, Switzerland, 2008.
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  @inproceedings{info3-inproceedings-2008-442, address = {Zurich, Switzerland}, author = {Stiller, Burkhard and Hoßfeld, Tobias}, booktitle = {Joint EC-GIN, EMANICS, and SmoothIT Workshop Economic Traffic Management}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Modeling of P2P-based Video Streaming}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-442 %A Stiller, Burkhard %A Hoßfeld, Tobias %B Joint EC-GIN, EMANICS, and SmoothIT Workshop Economic Traffic Management %C Zurich, Switzerland %D 2008 %T Modeling of P2P-based Video Streaming
• QoS Provisioning in WLAN Mesh Networks Using Dynamic Bandwidth Control. Hock, David; Bayer, Nico; Pries, Rastin; Siebert, Matthias; Staehle, Dirk; Rakocevic, Veselin; Xu, Bangnan. In European Wireless 2008, p. 7. Prague, Czech Republic, 2008.
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  WLAN, based on the IEEE 802.11 standard has been extensively studied since its release. In addition to infrastructure access to WLAN, mesh networks currently attract a lot of attention. This comes from the envisioned advantages of wireless mesh networks, such as cheap installation costs, extended coverage, robustness, easy maintenance, and self-configuration possibilities. In this paper we focus on Quality of Service support for multimedia applications in WLAN-based mesh networks. Therefore, a dynamic bandwidth control mechanism is implemented on the network layer and the results show that high prioritized traffic can be protected from disturbing best effort traffic.

  @inproceedings{info3-inproceedings-2008-316, abstract = {WLAN, based on the IEEE 802.11 standard has been extensively studied since its release. In addition to infrastructure access to WLAN, mesh networks currently attract a lot of attention. This comes from the envisioned advantages of wireless mesh networks, such as cheap installation costs, extended coverage, robustness, easy maintenance, and self-configuration possibilities. In this paper we focus on Quality of Service support for multimedia applications in WLAN-based mesh networks. Therefore, a dynamic bandwidth control mechanism is implemented on the network layer and the results show that high prioritized traffic can be protected from disturbing best effort traffic.}, address = {Prague, Czech Republic}, author = {Hock, David and Bayer, Nico and Pries, Rastin and Siebert, Matthias and Staehle, Dirk and Rakocevic, Veselin and Xu, Bangnan}, booktitle = {European Wireless 2008}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = 7, title = {QoS Provisioning in WLAN Mesh Networks Using Dynamic Bandwidth Control}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-316 %A Hock, David %A Bayer, Nico %A Pries, Rastin %A Siebert, Matthias %A Staehle, Dirk %A Rakocevic, Veselin %A Xu, Bangnan %B European Wireless 2008 %C Prague, Czech Republic %D 2008 %P 7 %T QoS Provisioning in WLAN Mesh Networks Using Dynamic Bandwidth Control %X WLAN, based on the IEEE 802.11 standard has been extensively studied since its release. In addition to infrastructure access to WLAN, mesh networks currently attract a lot of attention. This comes from the envisioned advantages of wireless mesh networks, such as cheap installation costs, extended coverage, robustness, easy maintenance, and self-configuration possibilities. In this paper we focus on Quality of Service support for multimedia applications in WLAN-based mesh networks. Therefore, a dynamic bandwidth control mechanism is implemented on the network layer and the results show that high prioritized traffic can be protected from disturbing best effort traffic.
• Exact Sojourn Time Distribution in an Online IPTV Recording Service. Hoßfeld, Tobias; Leibnitz, Kenji; Remiche, Marie-Ange. In 15th International Conference on Analytical and Stochastic Modelling Techniques and Applications (ASMTA 2008). Nicosia, Cyprus, 2008.
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  In this paper we analytically derive the sojourn time of a user accessing an online IPTV recording service. Basically, the system consists of a server (or server farm) and the bandwidth at which a user can download recorded files depends on the number of other concurrently downloading users. In particular, we consider both cases, one in which the user’s download speed is limited by his own access bandwidth, whereas in the other case the server is the bottleneck and all downloading users share the server’s upload capacity. Our model includes user impatience which depends on the actual download speed. A user may abort his download attempt if a threshold duration is exceeded. The file size distribution is obtained by measurements of offered files at an existing server.

  @inproceedings{info3-inproceedings-2008-315, abstract = {In this paper we analytically derive the sojourn time of a user accessing an online IPTV recording service. Basically, the system consists of a server (or server farm) and the bandwidth at which a user can download recorded files depends on the number of other concurrently downloading users. In particular, we consider both cases, one in which the user’s download speed is limited by his own access bandwidth, whereas in the other case the server is the bottleneck and all downloading users share the server’s upload capacity. Our model includes user impatience which depends on the actual download speed. A user may abort his download attempt if a threshold duration is exceeded. The file size distribution is obtained by measurements of offered files at an existing server.}, address = {Nicosia, Cyprus}, author = {Hoßfeld, Tobias and Leibnitz, Kenji and Remiche, Marie-Ange}, booktitle = {15th International Conference on Analytical and Stochastic Modelling Techniques and Applications (ASMTA 2008)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Exact Sojourn Time Distribution in an Online IPTV Recording Service}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-315 %A Hoßfeld, Tobias %A Leibnitz, Kenji %A Remiche, Marie-Ange %B 15th International Conference on Analytical and Stochastic Modelling Techniques and Applications (ASMTA 2008) %C Nicosia, Cyprus %D 2008 %T Exact Sojourn Time Distribution in an Online IPTV Recording Service %X In this paper we analytically derive the sojourn time of a user accessing an online IPTV recording service. Basically, the system consists of a server (or server farm) and the bandwidth at which a user can download recorded files depends on the number of other concurrently downloading users. In particular, we consider both cases, one in which the user’s download speed is limited by his own access bandwidth, whereas in the other case the server is the bottleneck and all downloading users share the server’s upload capacity. Our model includes user impatience which depends on the actual download speed. A user may abort his download attempt if a threshold duration is exceeded. The file size distribution is obtained by measurements of offered files at an existing server.
• Performance Evaluation of PCN-Based Admission Control. Menth, Michael; Lehrieder, Frank. In 16th International Workshop on Quality of Service (IWQoS). Enschede, Netherlands, 2008.
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  @inproceedings{info3-inproceedings-2008-320, address = {Enschede, Netherlands}, author = {Menth, Michael and Lehrieder, Frank}, booktitle = {16th International Workshop on Quality of Service (IWQoS)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Performance Evaluation of PCN-Based Admission Control}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-320 %A Menth, Michael %A Lehrieder, Frank %B 16th International Workshop on Quality of Service (IWQoS) %C Enschede, Netherlands %D 2008 %T Performance Evaluation of PCN-Based Admission Control
• A Qualitative Measurement Survey of Popular Internet-based IPTV Systems. Hoßfeld, Tobias; Leibnitz, Kenji. In Second International Conference on Communications and Electronics (HUT-ICCE 2008). Hoi An, Vietnam, 2008.
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  Television has traditionally been an entirely broadcastoriented medium. However, nowadays, new technologies delivering packetized digital video data are on the brink of replacing conventional television broadcasts via terrestrial, satellite or cable transmissions. With increasing access bandwidth speeds for end users, the new Internet-based television (IPTV) has gained popularity as a means of delivering high-quality video images. One of its main features is its high degree of interactivity. Users are no longer restricted to the broadcast schedules of TV stations, but can choose the program they wish to see on-demand, whenever, wherever, and on whatever device they want (TV, PC, portable player). Additionally, further value-added services are often included, such as chat functions or other feedback mechanisms allowing the viewers to provide ratings or discussion forums on the shows. The technological advancement in high-speed Internet accesses facilitates such possibilities. Meanwhile, a large coverage of DSL or fiber-to-the-home (FTTH) is available and improved video encoders like H.264 permit the transmission of clear high-resolution video images at half the bitrate of MPEG2 current on DVDs. In addition, offering IPTV has now also become an attractive business model for telecommunication service providers. Many providers no longer limit their offer just on telephone or Internet access, but provide so-called triple play services, integrating Internet, voice-over-IP (VoIP) telephone services, as well as television or movie channels. Furthermore, it is also appealing to businesses, which can offer personalized advertisements, individually tuned to the TV programs the customer is currently watching or localized to his region of access. However, one problem in IPTV is that content is licensed differently in different regions and therefore some IPTV solutions, e.g. Zattoo (Europe) or Gyao (Japan), limit their access only to IP addresses from those regions. In this paper we characterize some of the popular existing IPTV solutions by describing their architectures and characterizing their traffic through measurements. We focus on the applications Zattoo, Joost, YouTube, PPLive and OTR, and point out their differences in system architecture and technology. Especially in the case of proprietary systems, measurements at the edge of the network are the only feasible way to evaluate the Quality of Service/Experience (QoS/QoE) of an arbitrary user. Nevertheless, it allows us to identify the used protocols and constructed overlay topologies.

  @inproceedings{info3-inproceedings-2008-314, abstract = {Television has traditionally been an entirely broadcastoriented medium. However, nowadays, new technologies delivering packetized digital video data are on the brink of replacing conventional television broadcasts via terrestrial, satellite or cable transmissions. With increasing access bandwidth speeds for end users, the new Internet-based television (IPTV) has gained popularity as a means of delivering high-quality video images. One of its main features is its high degree of interactivity. Users are no longer restricted to the broadcast schedules of TV stations, but can choose the program they wish to see on-demand, whenever, wherever, and on whatever device they want (TV, PC, portable player). Additionally, further value-added services are often included, such as chat functions or other feedback mechanisms allowing the viewers to provide ratings or discussion forums on the shows. The technological advancement in high-speed Internet accesses facilitates such possibilities. Meanwhile, a large coverage of DSL or fiber-to-the-home (FTTH) is available and improved video encoders like H.264 permit the transmission of clear high-resolution video images at half the bitrate of MPEG2 current on DVDs. In addition, offering IPTV has now also become an attractive business model for telecommunication service providers. Many providers no longer limit their offer just on telephone or Internet access, but provide so-called triple play services, integrating Internet, voice-over-IP (VoIP) telephone services, as well as television or movie channels. Furthermore, it is also appealing to businesses, which can offer personalized advertisements, individually tuned to the TV programs the customer is currently watching or localized to his region of access. However, one problem in IPTV is that content is licensed differently in different regions and therefore some IPTV solutions, e.g. Zattoo (Europe) or Gyao (Japan), limit their access only to IP addresses from those regions. In this paper we characterize some of the popular existing IPTV solutions by describing their architectures and characterizing their traffic through measurements. We focus on the applications Zattoo, Joost, YouTube, PPLive and OTR, and point out their differences in system architecture and technology. Especially in the case of proprietary systems, measurements at the edge of the network are the only feasible way to evaluate the Quality of Service/Experience (QoS/QoE) of an arbitrary user. Nevertheless, it allows us to identify the used protocols and constructed overlay topologies.}, address = {Hoi An, Vietnam}, author = {Hoßfeld, Tobias and Leibnitz, Kenji}, booktitle = {Second International Conference on Communications and Electronics (HUT-ICCE 2008)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {A Qualitative Measurement Survey of Popular Internet-based IPTV Systems}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-314 %A Hoßfeld, Tobias %A Leibnitz, Kenji %B Second International Conference on Communications and Electronics (HUT-ICCE 2008) %C Hoi An, Vietnam %D 2008 %T A Qualitative Measurement Survey of Popular Internet-based IPTV Systems %X Television has traditionally been an entirely broadcastoriented medium. However, nowadays, new technologies delivering packetized digital video data are on the brink of replacing conventional television broadcasts via terrestrial, satellite or cable transmissions. With increasing access bandwidth speeds for end users, the new Internet-based television (IPTV) has gained popularity as a means of delivering high-quality video images. One of its main features is its high degree of interactivity. Users are no longer restricted to the broadcast schedules of TV stations, but can choose the program they wish to see on-demand, whenever, wherever, and on whatever device they want (TV, PC, portable player). Additionally, further value-added services are often included, such as chat functions or other feedback mechanisms allowing the viewers to provide ratings or discussion forums on the shows. The technological advancement in high-speed Internet accesses facilitates such possibilities. Meanwhile, a large coverage of DSL or fiber-to-the-home (FTTH) is available and improved video encoders like H.264 permit the transmission of clear high-resolution video images at half the bitrate of MPEG2 current on DVDs. In addition, offering IPTV has now also become an attractive business model for telecommunication service providers. Many providers no longer limit their offer just on telephone or Internet access, but provide so-called triple play services, integrating Internet, voice-over-IP (VoIP) telephone services, as well as television or movie channels. Furthermore, it is also appealing to businesses, which can offer personalized advertisements, individually tuned to the TV programs the customer is currently watching or localized to his region of access. However, one problem in IPTV is that content is licensed differently in different regions and therefore some IPTV solutions, e.g. Zattoo (Europe) or Gyao (Japan), limit their access only to IP addresses from those regions. In this paper we characterize some of the popular existing IPTV solutions by describing their architectures and characterizing their traffic through measurements. We focus on the applications Zattoo, Joost, YouTube, PPLive and OTR, and point out their differences in system architecture and technology. Especially in the case of proprietary systems, measurements at the edge of the network are the only feasible way to evaluate the Quality of Service/Experience (QoS/QoE) of an arbitrary user. Nevertheless, it allows us to identify the used protocols and constructed overlay topologies.
• Dynamic Contention Window Adaptation (DCWA) in IEEE 802.11e Wireless Local Area Networks. Pries, Rastin; Menth, Stefan; Staehle, Dirk; Menth, Michael; Tran-Gia, Phuoc. In The Second International Conference on Communications and Electronics, HUT-ICCE 2008, pp. 92–97. Hoi An, Vietnam, 2008.
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  The Wireless LAN Medium Access Control (MAC) protocol is responsible for an efficient sharing of the limited communication bandwidth. With the demand for Quality of Service (QoS), which is supported by different traffic classes in 802.11e, this task becomes even more complex. In this paper, we present a Dynamic Contention Window Adaptation (DCWA) algorithm which adapts the contention window parameters for a single traffic class such that they are as small as possible to meet realtime conditions and large enough to cope with the current network load. The results reveal that the DCWA increases the overall cell capacity significantly compared to the fixed IEEE standard settings, it adaptively minimizes the contention delay when possible and maximizes the throughput when needed. Furthermore, we extended the method to handle competing high and low priority traffic and showed that the new mechanism can effectively protect voice from best effort traffic.

  @inproceedings{info3-inproceedings-2008-322, abstract = {The Wireless LAN Medium Access Control (MAC) protocol is responsible for an efficient sharing of the limited communication bandwidth. With the demand for Quality of Service (QoS), which is supported by different traffic classes in 802.11e, this task becomes even more complex. In this paper, we present a Dynamic Contention Window Adaptation (DCWA) algorithm which adapts the contention window parameters for a single traffic class such that they are as small as possible to meet realtime conditions and large enough to cope with the current network load. The results reveal that the DCWA increases the overall cell capacity significantly compared to the fixed IEEE standard settings, it adaptively minimizes the contention delay when possible and maximizes the throughput when needed. Furthermore, we extended the method to handle competing high and low priority traffic and showed that the new mechanism can effectively protect voice from best effort traffic.}, address = {Hoi An, Vietnam}, author = {Pries, Rastin and Menth, Stefan and Staehle, Dirk and Menth, Michael and Tran-Gia, Phuoc}, booktitle = {The Second International Conference on Communications and Electronics, HUT-ICCE 2008}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = {92–97}, title = {Dynamic Contention Window Adaptation (DCWA) in IEEE 802.11e Wireless Local Area Networks}, year = 2008 }

  %0 Conference Paper %1 info3-inproceedings-2008-322 %A Pries, Rastin %A Menth, Stefan %A Staehle, Dirk %A Menth, Michael %A Tran-Gia, Phuoc %B The Second International Conference on Communications and Electronics, HUT-ICCE 2008 %C Hoi An, Vietnam %D 2008 %P 92--97 %T Dynamic Contention Window Adaptation (DCWA) in IEEE 802.11e Wireless Local Area Networks %X The Wireless LAN Medium Access Control (MAC) protocol is responsible for an efficient sharing of the limited communication bandwidth. With the demand for Quality of Service (QoS), which is supported by different traffic classes in 802.11e, this task becomes even more complex. In this paper, we present a Dynamic Contention Window Adaptation (DCWA) algorithm which adapts the contention window parameters for a single traffic class such that they are as small as possible to meet realtime conditions and large enough to cope with the current network load. The results reveal that the DCWA increases the overall cell capacity significantly compared to the fixed IEEE standard settings, it adaptively minimizes the contention delay when possible and maximizes the throughput when needed. Furthermore, we extended the method to handle competing high and low priority traffic and showed that the new mechanism can effectively protect voice from best effort traffic.

• An Autonomic Approach to Verify End-to-End Communication Quality. Binzenhöfer, Andreas; Schlosser, Daniel; Tutschku, Kurt; Fiedler, Markus. In Tenth IFIP-IEEE International Symposium on Integrated Network Management (IM 2007). Munich, Germany, 2007.
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  @inproceedings{info3-inproceedings-2007-263, address = {Munich, Germany}, author = {Binzenhöfer, Andreas and Schlosser, Daniel and Tutschku, Kurt and Fiedler, Markus}, booktitle = {Tenth IFIP-IEEE International Symposium on Integrated Network Management (IM 2007)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {An Autonomic Approach to Verify End-to-End Communication Quality}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-263 %A Binzenhöfer, Andreas %A Schlosser, Daniel %A Tutschku, Kurt %A Fiedler, Markus %B Tenth IFIP-IEEE International Symposium on Integrated Network Management (IM 2007) %C Munich, Germany %D 2007 %T An Autonomic Approach to Verify End-to-End Communication Quality
• Robust IP Link Costs for Multilayer Resilience. Menth, Michael; Hartmann, Matthias; Martin, Rüdiger. In 6th IFIP-TC6 Networking Conference (Networking). Atlanta, GA, USA, 2007.
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  In this work we optimize administrative link costs of IP networks in such a way that the maximum utilization of all links is as low as possible for a set of considered failure scenarios (e.g., all single link failures). To that aim, we present the new 'hill hopping' heuristic with three different variants and compare their computation times and the quality of their results. We adapt the objective function of the heuristic to make the link cost settings robust to single link failures, single node failures, and single link or node failures, and compare the results. In particular, we optimize the routing for multilayer networks where unused backup capacity of the link layer can be reused to redirect traffic on the network layer in case of an IP node failure.

  @inproceedings{info3-inproceedings-2007-284, abstract = {In this work we optimize administrative link costs of IP networks in such a way that the maximum utilization of all links is as low as possible for a set of considered failure scenarios (e.g., all single link failures). To that aim, we present the new 'hill hopping' heuristic with three different variants and compare their computation times and the quality of their results. We adapt the objective function of the heuristic to make the link cost settings robust to single link failures, single node failures, and single link or node failures, and compare the results. In particular, we optimize the routing for multilayer networks where unused backup capacity of the link layer can be reused to redirect traffic on the network layer in case of an IP node failure.}, address = {Atlanta, GA, USA}, author = {Menth, Michael and Hartmann, Matthias and Martin, Rüdiger}, booktitle = {6th IFIP-TC6 Networking Conference (Networking)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Robust IP Link Costs for Multilayer Resilience}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-284 %A Menth, Michael %A Hartmann, Matthias %A Martin, Rüdiger %B 6th IFIP-TC6 Networking Conference (Networking) %C Atlanta, GA, USA %D 2007 %T Robust IP Link Costs for Multilayer Resilience %X In this work we optimize administrative link costs of IP networks in such a way that the maximum utilization of all links is as low as possible for a set of considered failure scenarios (e.g., all single link failures). To that aim, we present the new 'hill hopping' heuristic with three different variants and compare their computation times and the quality of their results. We adapt the objective function of the heuristic to make the link cost settings robust to single link failures, single node failures, and single link or node failures, and compare the results. In particular, we optimize the routing for multilayer networks where unused backup capacity of the link layer can be reused to redirect traffic on the network layer in case of an IP node failure.
• Integer SPM: Intelligent Path Selection for Resilient Networks. Martin, Rüdiger; Menth, Michael; Spörlein, Ulrich. In 6th IFIP-TC6 Networking Conference (Networking). Atlanta, GA, USA, 2007.
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  @inproceedings{info3-inproceedings-2007-262, address = {Atlanta, GA, USA}, author = {Martin, Rüdiger and Menth, Michael and Spörlein, Ulrich}, booktitle = {6th IFIP-TC6 Networking Conference (Networking)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Integer SPM: Intelligent Path Selection for Resilient Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-262 %A Martin, Rüdiger %A Menth, Michael %A Spörlein, Ulrich %B 6th IFIP-TC6 Networking Conference (Networking) %C Atlanta, GA, USA %D 2007 %T Integer SPM: Intelligent Path Selection for Resilient Networks
• Peer-to-Peer vs. Client/Server: Reliability and Efficiency of a Content Distribution Service. Leibnitz, Kenji; Hoßfeld, Tobias; Wakamiya, Naoki; Murata, Masayuki. In 20th International Teletraffic Congress (ITC20). Ottawa, Canada, 2007.
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  In this paper we evaluate the performance of a content distribution service with respect to reliability and efficiency. The considered technology for realizing such a service can either be a traditional client/server (CS) architecture or a peer-to-peer (P2P) network. In CS, the capacity of the server is the bottleneck and has to be dimensioned in such a way that all requests can be accommodated at any time, while a P2P system does not burden a single server since the content is distributed in the network among sharing peers. However, corrupted or fake files may diminish the reliability of the P2P service due to downloading of useless contents. We compare a CS system to P2P and evaluate the downloading time, success ratio, and fairness while considering flash crowd arrivals and corrupted contents.

  @inproceedings{info3-inproceedings-2007-265, abstract = {In this paper we evaluate the performance of a content distribution service with respect to reliability and efficiency. The considered technology for realizing such a service can either be a traditional client/server (CS) architecture or a peer-to-peer (P2P) network. In CS, the capacity of the server is the bottleneck and has to be dimensioned in such a way that all requests can be accommodated at any time, while a P2P system does not burden a single server since the content is distributed in the network among sharing peers. However, corrupted or fake files may diminish the reliability of the P2P service due to downloading of useless contents. We compare a CS system to P2P and evaluate the downloading time, success ratio, and fairness while considering flash crowd arrivals and corrupted contents.}, address = {Ottawa, Canada}, author = {Leibnitz, Kenji and Hoßfeld, Tobias and Wakamiya, Naoki and Murata, Masayuki}, booktitle = {20th International Teletraffic Congress (ITC20)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Peer-to-Peer vs. Client/Server: Reliability and Efficiency of a Content Distribution Service}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-265 %A Leibnitz, Kenji %A Hoßfeld, Tobias %A Wakamiya, Naoki %A Murata, Masayuki %B 20th International Teletraffic Congress (ITC20) %C Ottawa, Canada %D 2007 %T Peer-to-Peer vs. Client/Server: Reliability and Efficiency of a Content Distribution Service %X In this paper we evaluate the performance of a content distribution service with respect to reliability and efficiency. The considered technology for realizing such a service can either be a traditional client/server (CS) architecture or a peer-to-peer (P2P) network. In CS, the capacity of the server is the bottleneck and has to be dimensioned in such a way that all requests can be accommodated at any time, while a P2P system does not burden a single server since the content is distributed in the network among sharing peers. However, corrupted or fake files may diminish the reliability of the P2P service due to downloading of useless contents. We compare a CS system to P2P and evaluate the downloading time, success ratio, and fairness while considering flash crowd arrivals and corrupted contents.
• An Algorithmic Framework for Discrete-Time Flow-Level Simulation of Data Networks. Jansen, Lasse; Gojmerac, Ivan; Menth, Michael; Reichl, Peter; Tran-Gia, Phuoc. In International Teletraffic Congress (ITC). Ottawa, Canada, 2007.
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  @inproceedings{info3-inproceedings-2007-276, address = {Ottawa, Canada}, author = {Jansen, Lasse and Gojmerac, Ivan and Menth, Michael and Reichl, Peter and Tran-Gia, Phuoc}, booktitle = {International Teletraffic Congress (ITC)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {An Algorithmic Framework for Discrete-Time Flow-Level Simulation of Data Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-276 %A Jansen, Lasse %A Gojmerac, Ivan %A Menth, Michael %A Reichl, Peter %A Tran-Gia, Phuoc %B International Teletraffic Congress (ITC) %C Ottawa, Canada %D 2007 %T An Algorithmic Framework for Discrete-Time Flow-Level Simulation of Data Networks
• Quantification of Quality of Experience for Edge-Based Applications. Hoßfeld, Tobias; Tran-Gia, Phuoc; Fiedler, Markus. In 20th International Teletraffic Congress (ITC20). Ottawa, Canada, 2007.
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  In future Internet,multi-network services correspond to a new paradigm that intelligence in network control is gradually moved to the edge of the network. As a consequence, the application itself can influence or determine the amount of consumed bandwidth. Thus the user behaviour may change dramatically. This impacts the Quality of Service (QoS) and the Quality of Experience (QoE), a subjective measure from the user perspective of the overall value of the provided service or application. A selfish user or application tries to maximize its own QoE rather than to optimize the network QoS, in contrast to a legacy altruistic user. In this paper we present the IQX hypothesis which assumes an exponential functional relationship between QoE and QoS. This contribution is a first step towards the quantification of the QoE for edge-based applications, where an example of VoIP is taken into account. Starting from a measurement of the Skype application, we show the basic properties of selfish and altruistic user behaviour in accordance to edge-based intelligence. The QoE is quantified in terms ofMOS in dependence of the packet loss of the end-to-end connection, whereby Skype’s iLBC voice codec is used exemplarily. It is shown that the IQX hypothesis is verified in this application scenario. Furthermore, selfish user behaviour with replicated sending of voice datagrams is investigated with respect to the obtained QoE of a single user. In addition, the impact of this user behaviour on congestion in the network is outlined by means of simulations.

  @inproceedings{info3-inproceedings-2007-264, abstract = {In future Internet,multi-network services correspond to a new paradigm that intelligence in network control is gradually moved to the edge of the network. As a consequence, the application itself can influence or determine the amount of consumed bandwidth. Thus the user behaviour may change dramatically. This impacts the Quality of Service (QoS) and the Quality of Experience (QoE), a subjective measure from the user perspective of the overall value of the provided service or application. A selfish user or application tries to maximize its own QoE rather than to optimize the network QoS, in contrast to a legacy altruistic user. In this paper we present the IQX hypothesis which assumes an exponential functional relationship between QoE and QoS. This contribution is a first step towards the quantification of the QoE for edge-based applications, where an example of VoIP is taken into account. Starting from a measurement of the Skype application, we show the basic properties of selfish and altruistic user behaviour in accordance to edge-based intelligence. The QoE is quantified in terms ofMOS in dependence of the packet loss of the end-to-end connection, whereby Skype’s iLBC voice codec is used exemplarily. It is shown that the IQX hypothesis is verified in this application scenario. Furthermore, selfish user behaviour with replicated sending of voice datagrams is investigated with respect to the obtained QoE of a single user. In addition, the impact of this user behaviour on congestion in the network is outlined by means of simulations.}, address = {Ottawa, Canada}, author = {Hoßfeld, Tobias and Tran-Gia, Phuoc and Fiedler, Markus}, booktitle = {20th International Teletraffic Congress (ITC20)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Quantification of Quality of Experience for Edge-Based Applications}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-264 %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %A Fiedler, Markus %B 20th International Teletraffic Congress (ITC20) %C Ottawa, Canada %D 2007 %T Quantification of Quality of Experience for Edge-Based Applications %X In future Internet,multi-network services correspond to a new paradigm that intelligence in network control is gradually moved to the edge of the network. As a consequence, the application itself can influence or determine the amount of consumed bandwidth. Thus the user behaviour may change dramatically. This impacts the Quality of Service (QoS) and the Quality of Experience (QoE), a subjective measure from the user perspective of the overall value of the provided service or application. A selfish user or application tries to maximize its own QoE rather than to optimize the network QoS, in contrast to a legacy altruistic user. In this paper we present the IQX hypothesis which assumes an exponential functional relationship between QoE and QoS. This contribution is a first step towards the quantification of the QoE for edge-based applications, where an example of VoIP is taken into account. Starting from a measurement of the Skype application, we show the basic properties of selfish and altruistic user behaviour in accordance to edge-based intelligence. The QoE is quantified in terms ofMOS in dependence of the packet loss of the end-to-end connection, whereby Skype’s iLBC voice codec is used exemplarily. It is shown that the IQX hypothesis is verified in this application scenario. Furthermore, selfish user behaviour with replicated sending of voice datagrams is investigated with respect to the obtained QoE of a single user. In addition, the impact of this user behaviour on congestion in the network is outlined by means of simulations.
• Impact of Complex Filters on the Message Throughput of the ActiveMQ JMS Server. Henjes, Robert; Menth, Michael; Himmler, Valentin. In International Teletraffic Congress (ITC). Ottawa, Canada, 2007.
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  @inproceedings{info3-inproceedings-2007-274, address = {Ottawa, Canada}, author = {Henjes, Robert and Menth, Michael and Himmler, Valentin}, booktitle = {International Teletraffic Congress (ITC)}, keywords = {dirc}, month = {06}, title = {Impact of Complex Filters on the Message Throughput of the ActiveMQ JMS Server}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-274 %A Henjes, Robert %A Menth, Michael %A Himmler, Valentin %B International Teletraffic Congress (ITC) %C Ottawa, Canada %D 2007 %T Impact of Complex Filters on the Message Throughput of the ActiveMQ JMS Server
• Performance Evaluation of a Reliable Content Mediation Platform in the Emerging Future Internet. Oechsner, Simon; Tran-Gia, Phuoc. In 20th International Teletraffic Congress (ITC20). Ottawa, Canada, 2007.
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  @inproceedings{info3-inproceedings-2007-272, address = {Ottawa, Canada}, author = {Oechsner, Simon and Tran-Gia, Phuoc}, booktitle = {20th International Teletraffic Congress (ITC20)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Performance Evaluation of a Reliable Content Mediation Platform in the Emerging Future Internet}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-272 %A Oechsner, Simon %A Tran-Gia, Phuoc %B 20th International Teletraffic Congress (ITC20) %C Ottawa, Canada %D 2007 %T Performance Evaluation of a Reliable Content Mediation Platform in the Emerging Future Internet
• Modeling and Evaluation of an Online TV Recording Service. Hoßfeld, Tobias; Leibnitz, Kenji. In Ninth annual workshop on mathematical performance modeling and analysis MAMA2007, in conjunction with ACM SIGMETRICS ’07 and FCRC ’07. San Diego, CA, USA, 2007.
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  Recently, new services have emerged which utilize the Internet as a delivery mechanism for multimedia content. With the advent of broadband accesses, more users are willing to download large volume content from servers, such as video files of TV shows. While some popular video services (e.g. YouTube.com) or some broadcasting companies (e.g. ABC.com) use streaming data with Flash technology, some media distributors (e.g. iTunes) offer entire TV shows for download. In this study, we investigate the performance of the German site OnlineTVRecorder.com (OTR), which acts as an online video cassette recorder (VCR) where users can program their favorite shows over a web interface and download the recorded files from a server or its mirrors. These files are offered in different formats and can consist of several hundred megabytes up to 1GB or more depending on the length of the TV show as well as the encoding format. OTR can, thus, be seen as an example for a server-based content distribution system with large data files. However, as these server farms are often overloaded, new requests are queued when the provided download slots are full. The restriction to a maximum number of simultaneous downloads guarantees a minimal download bandwidth for each user. Additionally, the service offers premium users prioritized access to downloading. The download duration itself depends on the total capacity of the server and the number of users sharing this capacity. On the other hand, users who might encounter slow downloads may abort their downloading attempt if their patience is exceeded. In this paper, we discuss the impact of the user’s impatience on the performance of such an OTR server with different file size distributions. The paper is organized as follows. After describing the problem and formulating simple analytical models, we provide numerical results and compare their performance in terms of download duration and success ratio. Especially, we address the question of how to properly dimension the number of simultaneous downloads at a server in order to optimize the performance of the system and to maximize the user’s satisfaction.

  @inproceedings{info3-inproceedings-2007-283, abstract = {Recently, new services have emerged which utilize the Internet as a delivery mechanism for multimedia content. With the advent of broadband accesses, more users are willing to download large volume content from servers, such as video files of TV shows. While some popular video services (e.g. YouTube.com) or some broadcasting companies (e.g. ABC.com) use streaming data with Flash technology, some media distributors (e.g. iTunes) offer entire TV shows for download. In this study, we investigate the performance of the German site OnlineTVRecorder.com (OTR), which acts as an online video cassette recorder (VCR) where users can program their favorite shows over a web interface and download the recorded files from a server or its mirrors. These files are offered in different formats and can consist of several hundred megabytes up to 1GB or more depending on the length of the TV show as well as the encoding format. OTR can, thus, be seen as an example for a server-based content distribution system with large data files. However, as these server farms are often overloaded, new requests are queued when the provided download slots are full. The restriction to a maximum number of simultaneous downloads guarantees a minimal download bandwidth for each user. Additionally, the service offers premium users prioritized access to downloading. The download duration itself depends on the total capacity of the server and the number of users sharing this capacity. On the other hand, users who might encounter slow downloads may abort their downloading attempt if their patience is exceeded. In this paper, we discuss the impact of the user’s impatience on the performance of such an OTR server with different file size distributions. The paper is organized as follows. After describing the problem and formulating simple analytical models, we provide numerical results and compare their performance in terms of download duration and success ratio. Especially, we address the question of how to properly dimension the number of simultaneous downloads at a server in order to optimize the performance of the system and to maximize the user’s satisfaction.}, address = {San Diego, CA, USA}, author = {Hoßfeld, Tobias and Leibnitz, Kenji}, booktitle = {Ninth annual workshop on mathematical performance modeling and analysis MAMA2007, in conjunction with ACM SIGMETRICS '07 and FCRC '07}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Modeling and Evaluation of an Online TV Recording Service}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-283 %A Hoßfeld, Tobias %A Leibnitz, Kenji %B Ninth annual workshop on mathematical performance modeling and analysis MAMA2007, in conjunction with ACM SIGMETRICS '07 and FCRC '07 %C San Diego, CA, USA %D 2007 %T Modeling and Evaluation of an Online TV Recording Service %X Recently, new services have emerged which utilize the Internet as a delivery mechanism for multimedia content. With the advent of broadband accesses, more users are willing to download large volume content from servers, such as video files of TV shows. While some popular video services (e.g. YouTube.com) or some broadcasting companies (e.g. ABC.com) use streaming data with Flash technology, some media distributors (e.g. iTunes) offer entire TV shows for download. In this study, we investigate the performance of the German site OnlineTVRecorder.com (OTR), which acts as an online video cassette recorder (VCR) where users can program their favorite shows over a web interface and download the recorded files from a server or its mirrors. These files are offered in different formats and can consist of several hundred megabytes up to 1GB or more depending on the length of the TV show as well as the encoding format. OTR can, thus, be seen as an example for a server-based content distribution system with large data files. However, as these server farms are often overloaded, new requests are queued when the provided download slots are full. The restriction to a maximum number of simultaneous downloads guarantees a minimal download bandwidth for each user. Additionally, the service offers premium users prioritized access to downloading. The download duration itself depends on the total capacity of the server and the number of users sharing this capacity. On the other hand, users who might encounter slow downloads may abort their downloading attempt if their patience is exceeded. In this paper, we discuss the impact of the user’s impatience on the performance of such an OTR server with different file size distributions. The paper is organized as follows. After describing the problem and formulating simple analytical models, we provide numerical results and compare their performance in terms of download duration and success ratio. Especially, we address the question of how to properly dimension the number of simultaneous downloads at a server in order to optimize the performance of the system and to maximize the user’s satisfaction.
• Impact of Multi-Failures in Survivable Networks. Martin, Rüdiger; Menth, Michael. In 8. ITG-Fachtagung Photonische Netze. Leipzig, Germany, 2007.
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  @inproceedings{info3-inproceedings-2007-299, address = {Leipzig, Germany}, author = {Martin, Rüdiger and Menth, Michael}, booktitle = {8. ITG-Fachtagung Photonische Netze}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Impact of Multi-Failures in Survivable Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-299 %A Martin, Rüdiger %A Menth, Michael %B 8. ITG-Fachtagung Photonische Netze %C Leipzig, Germany %D 2007 %T Impact of Multi-Failures in Survivable Networks
• Random Multiple Access in WiMAX: Problems and Solutions. Vinel, Alexey; Staehle, Dirk; Pries, Rastin. In 1st Workshop on WiMAX Wireless and Mobility (WEIRD) in conjunction with the WWIC 2007 Conference. Coimbra, Portugal, 2007.
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  @inproceedings{info3-inproceedings-2007-275, address = {Coimbra, Portugal}, author = {Vinel, Alexey and Staehle, Dirk and Pries, Rastin}, booktitle = {1st Workshop on WiMAX Wireless and Mobility (WEIRD) in conjunction with the WWIC 2007 Conference}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Random Multiple Access in WiMAX: Problems and Solutions}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-275 %A Vinel, Alexey %A Staehle, Dirk %A Pries, Rastin %B 1st Workshop on WiMAX Wireless and Mobility (WEIRD) in conjunction with the WWIC 2007 Conference %C Coimbra, Portugal %D 2007 %T Random Multiple Access in WiMAX: Problems and Solutions
• P2P-based Network and Service Operation for the Emerging Future Internet. Tutschku, Kurt. In Praxis der Informationsverarbeitung und Kommunikation - Special Issue on Current Trends in Network and Service Management. 2007.
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  @inproceedings{info3-inproceedings-2007-269, author = {Tutschku, Kurt}, booktitle = {Praxis der Informationsverarbeitung und Kommunikation - Special Issue on Current Trends in Network and Service Management}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {P2P-based Network and Service Operation for the Emerging Future Internet.}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-269 %A Tutschku, Kurt %B Praxis der Informationsverarbeitung und Kommunikation - Special Issue on Current Trends in Network and Service Management %D 2007 %T P2P-based Network and Service Operation for the Emerging Future Internet.
• Relying on Randomness - PlanetLab Experiments with Distributed File-Sharing Protocols. Norros, Ilkka; Pehkonen, Vesa; Reittu, Hannu; Binzenhöfer, Andreas; Tutschku, Kurt. In 3rd EURO-NGI Conference on Next Generation Internet Networks (NGI 2007). Trondheim, Norway, 2007.
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  @inproceedings{info3-inproceedings-2007-266, address = {Trondheim, Norway}, author = {Norros, Ilkka and Pehkonen, Vesa and Reittu, Hannu and Binzenhöfer, Andreas and Tutschku, Kurt}, booktitle = {3rd EURO-NGI Conference on Next Generation Internet Networks (NGI 2007)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Relying on Randomness - PlanetLab Experiments with Distributed File-Sharing Protocols}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-266 %A Norros, Ilkka %A Pehkonen, Vesa %A Reittu, Hannu %A Binzenhöfer, Andreas %A Tutschku, Kurt %B 3rd EURO-NGI Conference on Next Generation Internet Networks (NGI 2007) %C Trondheim, Norway %D 2007 %T Relying on Randomness - PlanetLab Experiments with Distributed File-Sharing Protocols
• Efficient Simulation of Large-Scale P2P Networks: Modeling Network Transmission Times. Kunzmann, Gerald; Nagel, Robert; Hoßfeld, Tobias; Binzenhöfer, Andreas; Eger, Kolja. In Workshop on Modeling, Simulation and Optimization of Peer-to-peer environments (MSOP2P) in conjunction with Euromicro (PDP 2007). Naples, Italy, 2007.
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  The ongoing process of globalization leads to a huge demand for highly scalable applications that are able to deal with millions of participants distributed all over the world. Peer-to-Peer (p2p) technology enables an arbitrary large number of users to participate in distributed services like content distribution or collaboration tools. In order to verify a new protocol’s performance and scalability simulation is a commonly used tool. First, predicting the network and peer behavior in the real world is only feasible if the simulation, i.e. all applied models as well as the peer state, is as realistic as possible. Second, many properties of the system only become observable when the number of participants is sufficiently large. Therefore, verifying the scalability of a system requires simulating huge worldwide networks. Due to limited processing power, central memory and availabe time, both requirements can only be fullfilled if the applied models are very efficient. In this paper we take a closer look at the network layer. We compare the most commonly-used network models and present a very efficient model for applying real-world network transmission times in large scale simulations.

  @inproceedings{info3-inproceedings-2007-252, abstract = {The ongoing process of globalization leads to a huge demand for highly scalable applications that are able to deal with millions of participants distributed all over the world. Peer-to-Peer (p2p) technology enables an arbitrary large number of users to participate in distributed services like content distribution or collaboration tools. In order to verify a new protocol’s performance and scalability simulation is a commonly used tool. First, predicting the network and peer behavior in the real world is only feasible if the simulation, i.e. all applied models as well as the peer state, is as realistic as possible. Second, many properties of the system only become observable when the number of participants is sufficiently large. Therefore, verifying the scalability of a system requires simulating huge worldwide networks. Due to limited processing power, central memory and availabe time, both requirements can only be fullfilled if the applied models are very efficient. In this paper we take a closer look at the network layer. We compare the most commonly-used network models and present a very efficient model for applying real-world network transmission times in large scale simulations.}, address = {Naples, Italy}, author = {Kunzmann, Gerald and Nagel, Robert and Hoßfeld, Tobias and Binzenhöfer, Andreas and Eger, Kolja}, booktitle = {Workshop on Modeling, Simulation and Optimization of Peer-to-peer environments (MSOP2P) in conjunction with Euromicro (PDP 2007)}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {Efficient Simulation of Large-Scale P2P Networks: Modeling Network Transmission Times}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-252 %A Kunzmann, Gerald %A Nagel, Robert %A Hoßfeld, Tobias %A Binzenhöfer, Andreas %A Eger, Kolja %B Workshop on Modeling, Simulation and Optimization of Peer-to-peer environments (MSOP2P) in conjunction with Euromicro (PDP 2007) %C Naples, Italy %D 2007 %T Efficient Simulation of Large-Scale P2P Networks: Modeling Network Transmission Times %X The ongoing process of globalization leads to a huge demand for highly scalable applications that are able to deal with millions of participants distributed all over the world. Peer-to-Peer (p2p) technology enables an arbitrary large number of users to participate in distributed services like content distribution or collaboration tools. In order to verify a new protocol’s performance and scalability simulation is a commonly used tool. First, predicting the network and peer behavior in the real world is only feasible if the simulation, i.e. all applied models as well as the peer state, is as realistic as possible. Second, many properties of the system only become observable when the number of participants is sufficiently large. Therefore, verifying the scalability of a system requires simulating huge worldwide networks. Due to limited processing power, central memory and availabe time, both requirements can only be fullfilled if the applied models are very efficient. In this paper we take a closer look at the network layer. We compare the most commonly-used network models and present a very efficient model for applying real-world network transmission times in large scale simulations.
• A Priori Detection of Link Overload due to Network Failures. Milbrandt, Jens; Menth, Michael; Lehrieder, Frank. In Kommunikation in Verteilten Systemen (KiVS). Bern, Switzerland, 2007.
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  @inproceedings{info3-inproceedings-2007-256, address = {Bern, Switzerland}, author = {Milbrandt, Jens and Menth, Michael and Lehrieder, Frank}, booktitle = {Kommunikation in Verteilten Systemen (KiVS)}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {A Priori Detection of Link Overload due to Network Failures}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-256 %A Milbrandt, Jens %A Menth, Michael %A Lehrieder, Frank %B Kommunikation in Verteilten Systemen (KiVS) %C Bern, Switzerland %D 2007 %T A Priori Detection of Link Overload due to Network Failures
• Comparison of Preemptive and Preserving Admission Control for the UMTS Enhanced Uplink. Mäder, Andreas; Staehle, Dirk. In KiVS 2007. Bern, Switzerland, 2007.
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  @inproceedings{info3-inproceedings-2007-257, address = {Bern, Switzerland}, author = {Mäder, Andreas and Staehle, Dirk}, booktitle = {KiVS 2007}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {Comparison of Preemptive and Preserving Admission Control for the UMTS Enhanced Uplink}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-257 %A Mäder, Andreas %A Staehle, Dirk %B KiVS 2007 %C Bern, Switzerland %D 2007 %T Comparison of Preemptive and Preserving Admission Control for the UMTS Enhanced Uplink
• Poster Abstract - A Co-Simulation Framework for Performance Comparison of Wireless Sensor Networks. Klein, Alexander; Tran-Gia, Phuoc. In EWSN 2007, p. 2. Delft, Netherlands, 2007.
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  @inproceedings{info3-inproceedings-2007-294, address = {Delft, Netherlands}, author = {Klein, Alexander and Tran-Gia, Phuoc}, booktitle = {EWSN 2007}, keywords = {sys:hidden:inproceedings}, month = {02}, pages = 2, title = {Poster Abstract - A Co-Simulation Framework for Performance Comparison of Wireless Sensor Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-294 %A Klein, Alexander %A Tran-Gia, Phuoc %B EWSN 2007 %C Delft, Netherlands %D 2007 %P 2 %T Poster Abstract - A Co-Simulation Framework for Performance Comparison of Wireless Sensor Networks
• Throughput Performance of the ActiveMQ JMS Server. Henjes, Robert; Menth, Michael; Himmler, Valentin. In ITG/GI Symposium Communication in Distributed Systems (KiVS). Bern, Switzerland, 2007.
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  @inproceedings{info3-inproceedings-2007-273, address = {Bern, Switzerland}, author = {Henjes, Robert and Menth, Michael and Himmler, Valentin}, booktitle = {ITG/GI Symposium Communication in Distributed Systems (KiVS)}, keywords = {dirc}, month = {02}, title = {Throughput Performance of the ActiveMQ JMS Server}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-273 %A Henjes, Robert %A Menth, Michael %A Himmler, Valentin %B ITG/GI Symposium Communication in Distributed Systems (KiVS) %C Bern, Switzerland %D 2007 %T Throughput Performance of the ActiveMQ JMS Server
• Improving the Performance and Robustness of Kademlia-based Overlay Networks. Binzenhöfer, Andreas; Schnabel, Holger. In KIVS 2007. Bern, Switzerland, 2007.
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  @inproceedings{info3-inproceedings-2007-253, address = {Bern, Switzerland}, author = {Binzenhöfer, Andreas and Schnabel, Holger}, booktitle = {KIVS 2007}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {Improving the Performance and Robustness of Kademlia-based Overlay Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-253 %A Binzenhöfer, Andreas %A Schnabel, Holger %B KIVS 2007 %C Bern, Switzerland %D 2007 %T Improving the Performance and Robustness of Kademlia-based Overlay Networks
• Efficient Simulation of Large-Scale P2P Networks: Compact Data Structures. Binzenhöfer, Andreas; Hoßfeld, Tobias; Kunzmann, Gerald; Eger, Kolja. In Workshop on Modeling, Simulation and Optimization of Peer-to-peer environments (MSOP2P) in conjunction with Euromicro (PDP 2007). Naples, Italy, 2007.
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  One of the most important design goals of current Peerto- Peer (p2p) technology is to be able to offer its service to an arbitrary large number of users. Discrete event simulation is often applied to quantitatively and qualitatively evaluate the performance and scalability of such systems before they are deployed. However, the number of users, processes and events which can be simulated is limited by both the central memory and the time available. In this paper we present compact data structures and event design algorithms, which are intended to be a further step towards efficient simulation of large scale p2p systems. In particular, we give guidelines on how to increase the number of peers which can be simulated and show how to find a good tradeoff between computational time and memory consumption in large scale p2p simulation.

  @inproceedings{info3-inproceedings-2007-251, abstract = {One of the most important design goals of current Peerto- Peer (p2p) technology is to be able to offer its service to an arbitrary large number of users. Discrete event simulation is often applied to quantitatively and qualitatively evaluate the performance and scalability of such systems before they are deployed. However, the number of users, processes and events which can be simulated is limited by both the central memory and the time available. In this paper we present compact data structures and event design algorithms, which are intended to be a further step towards efficient simulation of large scale p2p systems. In particular, we give guidelines on how to increase the number of peers which can be simulated and show how to find a good tradeoff between computational time and memory consumption in large scale p2p simulation.}, address = {Naples, Italy}, author = {Binzenhöfer, Andreas and Hoßfeld, Tobias and Kunzmann, Gerald and Eger, Kolja}, booktitle = {Workshop on Modeling, Simulation and Optimization of Peer-to-peer environments (MSOP2P) in conjunction with Euromicro (PDP 2007)}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {Efficient Simulation of Large-Scale P2P Networks: Compact Data Structures}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-251 %A Binzenhöfer, Andreas %A Hoßfeld, Tobias %A Kunzmann, Gerald %A Eger, Kolja %B Workshop on Modeling, Simulation and Optimization of Peer-to-peer environments (MSOP2P) in conjunction with Euromicro (PDP 2007) %C Naples, Italy %D 2007 %T Efficient Simulation of Large-Scale P2P Networks: Compact Data Structures %X One of the most important design goals of current Peerto- Peer (p2p) technology is to be able to offer its service to an arbitrary large number of users. Discrete event simulation is often applied to quantitatively and qualitatively evaluate the performance and scalability of such systems before they are deployed. However, the number of users, processes and events which can be simulated is limited by both the central memory and the time available. In this paper we present compact data structures and event design algorithms, which are intended to be a further step towards efficient simulation of large scale p2p systems. In particular, we give guidelines on how to increase the number of peers which can be simulated and show how to find a good tradeoff between computational time and memory consumption in large scale p2p simulation.
• Poster Abstract: Influence of Energy Models on Sensor Network Analysis. Emmert, Barbara. In 4th European conference on Wireless Sensor Networks. Delft, The Netherlands, 2007.
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  Algorithms and proposals for analyzing the energy consumption of sensor nodes often assume that transmission costs scale with a power of the distance. While this assumption is theoretically correct, it does not reflect the capabilities of real sensor nodes. Moreover, the omni-directional nature of radio transmissions which forces nodes to overhear the communication of other nodes is ignored by this approach. We therefore propose a novel and more realistic cost metric based on the current consumptions of existing sensor nodes that also includes increased energy consumption when processing unintendedly received packets.

  @inproceedings{info3-inproceedings-2007-255, abstract = {Algorithms and proposals for analyzing the energy consumption of sensor nodes often assume that transmission costs scale with a power of the distance. While this assumption is theoretically correct, it does not reflect the capabilities of real sensor nodes. Moreover, the omni-directional nature of radio transmissions which forces nodes to overhear the communication of other nodes is ignored by this approach. We therefore propose a novel and more realistic cost metric based on the current consumptions of existing sensor nodes that also includes increased energy consumption when processing unintendedly received packets.}, address = {Delft, The Netherlands}, author = {Emmert, Barbara}, booktitle = {4th European conference on Wireless Sensor Networks}, keywords = {sys:hidden:inproceedings}, month = {01}, title = {Poster Abstract: Influence of Energy Models on Sensor Network Analysis}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-255 %A Emmert, Barbara %B 4th European conference on Wireless Sensor Networks %C Delft, The Netherlands %D 2007 %T Poster Abstract: Influence of Energy Models on Sensor Network Analysis %X Algorithms and proposals for analyzing the energy consumption of sensor nodes often assume that transmission costs scale with a power of the distance. While this assumption is theoretically correct, it does not reflect the capabilities of real sensor nodes. Moreover, the omni-directional nature of radio transmissions which forces nodes to overhear the communication of other nodes is ignored by this approach. We therefore propose a novel and more realistic cost metric based on the current consumptions of existing sensor nodes that also includes increased energy consumption when processing unintendedly received packets.
• Feasible Load Regions for different RRM Strategies for the Enhanced Uplink in UMTS Networks. Mäder, Andreas; Staehle, Dirk; Liu, Tuo; Barth, Hans. In LNCS Volume 4369, Wireless Systems and Mobility in Next Generation Internet. 2007.
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  @inproceedings{info3-inproceedings-2007-258, author = {Mäder, Andreas and Staehle, Dirk and Liu, Tuo and Barth, Hans}, booktitle = {LNCS Volume 4369, Wireless Systems and Mobility in Next Generation Internet}, keywords = {sys:hidden:inproceedings}, month = {01}, title = {Feasible Load Regions for different RRM Strategies for the Enhanced Uplink in UMTS Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-258 %A Mäder, Andreas %A Staehle, Dirk %A Liu, Tuo %A Barth, Hans %B LNCS Volume 4369, Wireless Systems and Mobility in Next Generation Internet %D 2007 %T Feasible Load Regions for different RRM Strategies for the Enhanced Uplink in UMTS Networks
• On the Performance of Mobile IP in Wireless LAN Environments. Pries, Rastin; Mäder, Andreas; Staehle, Dirk; Wiesen, Matthias. In Wireless Systems and Mobility, LNCS 4396, pp. 155–170. Sitges, Spain, 2007.
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  @inproceedings{info3-inproceedings-2007-325, address = {Sitges, Spain}, author = {Pries, Rastin and Mäder, Andreas and Staehle, Dirk and Wiesen, Matthias}, booktitle = {Wireless Systems and Mobility, LNCS 4396}, keywords = {sys:hidden:inproceedings}, pages = {155–170}, title = {On the Performance of Mobile IP in Wireless LAN Environments}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-325 %A Pries, Rastin %A Mäder, Andreas %A Staehle, Dirk %A Wiesen, Matthias %B Wireless Systems and Mobility, LNCS 4396 %C Sitges, Spain %D 2007 %P 155--170 %T On the Performance of Mobile IP in Wireless LAN Environments
• A Novel Performance Model for the HSDPA with Adaptive Resource Allocation. Mäder, Andreas; Staehle, Dirk. In ITC 20. Ottawa, Canada, 2007.
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  @inproceedings{info3-inproceedings-2007-267, address = {Ottawa, Canada}, author = {Mäder, Andreas and Staehle, Dirk}, booktitle = {ITC 20}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {A Novel Performance Model for the HSDPA with Adaptive Resource Allocation}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-267 %A Mäder, Andreas %A Staehle, Dirk %B ITC 20 %C Ottawa, Canada %D 2007 %T A Novel Performance Model for the HSDPA with Adaptive Resource Allocation
• Efficient Simulation of Large-Scale P2P Networks: Packet-level vs. Flow-level Simulations. Eger, Kolja; Hoßfeld, Tobias; Binzenhöfer, Andreas; Kunzmann, Gerald. In 2nd Workshop on the Use of P2P, GRID and Agents for the Development of Content Networks (UPGRADE-CN’07) in conjunction with the 16th IEEE HPDC. Monterey Bay, California, USA, 2007.
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  Peer-to-peer (P2P) networks can reduce the distribution cost of large media files for the original provider of the data significantly. Thereby, the BitTorrent protocol is widely used in the Internet today. Most research work studies the protocol analytically, by simulations at the flow-level or real world experiments. Thereby, for flow-level simulations the influence of neglecting packet-level characteristics is not yet quantified. Therefore, this paper compares packetlevel simulation results with flow-level values and analytically derived bounds. Our findings show that BitTorrent is near to optimal at flow-level for different scenarios. Naturally, packet-level results deviate more from the optimal values but differences are at most around 30% in our simulations. Furthermore, we show that the propagation delay can significantly influence the download performance of BitTorrent.

  @inproceedings{info3-inproceedings-2007-268, abstract = {Peer-to-peer (P2P) networks can reduce the distribution cost of large media files for the original provider of the data significantly. Thereby, the BitTorrent protocol is widely used in the Internet today. Most research work studies the protocol analytically, by simulations at the flow-level or real world experiments. Thereby, for flow-level simulations the influence of neglecting packet-level characteristics is not yet quantified. Therefore, this paper compares packetlevel simulation results with flow-level values and analytically derived bounds. Our findings show that BitTorrent is near to optimal at flow-level for different scenarios. Naturally, packet-level results deviate more from the optimal values but differences are at most around 30% in our simulations. Furthermore, we show that the propagation delay can significantly influence the download performance of BitTorrent.}, address = {Monterey Bay, California, USA}, author = {Eger, Kolja and Hoßfeld, Tobias and Binzenhöfer, Andreas and Kunzmann, Gerald}, booktitle = {2nd Workshop on the Use of P2P, GRID and Agents for the Development of Content Networks (UPGRADE-CN'07) in conjunction with the 16th IEEE HPDC}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Efficient Simulation of Large-Scale P2P Networks: Packet-level vs. Flow-level Simulations}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-268 %A Eger, Kolja %A Hoßfeld, Tobias %A Binzenhöfer, Andreas %A Kunzmann, Gerald %B 2nd Workshop on the Use of P2P, GRID and Agents for the Development of Content Networks (UPGRADE-CN'07) in conjunction with the 16th IEEE HPDC %C Monterey Bay, California, USA %D 2007 %T Efficient Simulation of Large-Scale P2P Networks: Packet-level vs. Flow-level Simulations %X Peer-to-peer (P2P) networks can reduce the distribution cost of large media files for the original provider of the data significantly. Thereby, the BitTorrent protocol is widely used in the Internet today. Most research work studies the protocol analytically, by simulations at the flow-level or real world experiments. Thereby, for flow-level simulations the influence of neglecting packet-level characteristics is not yet quantified. Therefore, this paper compares packetlevel simulation results with flow-level values and analytically derived bounds. Our findings show that BitTorrent is near to optimal at flow-level for different scenarios. Naturally, packet-level results deviate more from the optimal values but differences are at most around 30% in our simulations. Furthermore, we show that the propagation delay can significantly influence the download performance of BitTorrent.
• Load-Balancing in Wireless Networks using Statistic-Based Routing. Klein, Alexander. In EuroView2007, p. 1. Wuerzburg, Germany, 2007.
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  @inproceedings{info3-inproceedings-2007-295, address = {Wuerzburg, Germany}, author = {Klein, Alexander}, booktitle = {EuroView2007}, keywords = {sys:hidden:inproceedings}, month = {07}, pages = 1, title = {Load-Balancing in Wireless Networks using Statistic-Based Routing}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-295 %A Klein, Alexander %B EuroView2007 %C Wuerzburg, Germany %D 2007 %P 1 %T Load-Balancing in Wireless Networks using Statistic-Based Routing
• Accuracy and Dynamics of Multi-Stage Load Balancing for Multipath Internet Routing. Martin, Rüdiger; Menth, Michael; Hemmkeppler, Michael. In IEEE International Conference on Communications (ICC). Glasgow, Scotland, 2007.
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  @inproceedings{info3-inproceedings-2007-259, address = {Glasgow, Scotland}, author = {Martin, Rüdiger and Menth, Michael and Hemmkeppler, Michael}, booktitle = {IEEE International Conference on Communications (ICC)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Accuracy and Dynamics of Multi-Stage Load Balancing for Multipath Internet Routing}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-259 %A Martin, Rüdiger %A Menth, Michael %A Hemmkeppler, Michael %B IEEE International Conference on Communications (ICC) %C Glasgow, Scotland %D 2007 %T Accuracy and Dynamics of Multi-Stage Load Balancing for Multipath Internet Routing
• Performance Evaluation of Piggyback Requests in IEEE 802.16. Pries, Rastin; Staehle, Dirk; Marsico, Daniel. In IEEE VTC Fall 07. Baltimore, MD, USA, 2007.
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  WiMAX (Worldwide Interoperability for Microwave Access) is a wireless access technology that aims to provide last mile wireless broadband access for fixed and mobile users as an alternative to the wired DSL and cable access. It is specified in the IEEE 802.16 standard. The standard defines several possible bandwidth request methods that can be implemented in an actual deployment of a WiMAX network. In this paper, we will study the performance of two different bandwidth request mechanisms, namely piggyback and broadcast requests and will show in which situations piggybacking performs better than the contention based broadcast bandwidth requests.

  @inproceedings{info3-inproceedings-2007-280, abstract = {WiMAX (Worldwide Interoperability for Microwave Access) is a wireless access technology that aims to provide last mile wireless broadband access for fixed and mobile users as an alternative to the wired DSL and cable access. It is specified in the IEEE 802.16 standard. The standard defines several possible bandwidth request methods that can be implemented in an actual deployment of a WiMAX network. In this paper, we will study the performance of two different bandwidth request mechanisms, namely piggyback and broadcast requests and will show in which situations piggybacking performs better than the contention based broadcast bandwidth requests.}, address = {Baltimore, MD, USA}, author = {Pries, Rastin and Staehle, Dirk and Marsico, Daniel}, booktitle = {IEEE VTC Fall 07}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Performance Evaluation of Piggyback Requests in IEEE 802.16}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-280 %A Pries, Rastin %A Staehle, Dirk %A Marsico, Daniel %B IEEE VTC Fall 07 %C Baltimore, MD, USA %D 2007 %T Performance Evaluation of Piggyback Requests in IEEE 802.16 %X WiMAX (Worldwide Interoperability for Microwave Access) is a wireless access technology that aims to provide last mile wireless broadband access for fixed and mobile users as an alternative to the wired DSL and cable access. It is specified in the IEEE 802.16 standard. The standard defines several possible bandwidth request methods that can be implemented in an actual deployment of a WiMAX network. In this paper, we will study the performance of two different bandwidth request mechanisms, namely piggyback and broadcast requests and will show in which situations piggybacking performs better than the contention based broadcast bandwidth requests.
• Optimization of the Self-Protecting Multipath for Deployment in Legacy Networks. Menth, Michael; Martin, Rüdiger; Spörlein, Ulrich. In IEEE International Conference on Communications (ICC). Glasgow, Scotland, 2007.
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  @inproceedings{info3-inproceedings-2007-260, address = {Glasgow, Scotland}, author = {Menth, Michael and Martin, Rüdiger and Spörlein, Ulrich}, booktitle = {IEEE International Conference on Communications (ICC)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Optimization of the Self-Protecting Multipath for Deployment in Legacy Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-260 %A Menth, Michael %A Martin, Rüdiger %A Spörlein, Ulrich %B IEEE International Conference on Communications (ICC) %C Glasgow, Scotland %D 2007 %T Optimization of the Self-Protecting Multipath for Deployment in Legacy Networks
• Performance Evaluation of an IPTV Recording Service. Hoßfeld, Tobias; Leibnitz, Kenji. In Invited Paper at the Jointly-organized Symposium of the Institute of Intelligent Information and Communications Technology (IICT) at Konan University and the ORSJ (Operations Research Society of Japan). Kobe, Japan, 2007.
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  @inproceedings{info3-inproceedings-2007-301, address = {Kobe, Japan}, author = {Hoßfeld, Tobias and Leibnitz, Kenji}, booktitle = {Invited Paper at the Jointly-organized Symposium of the Institute of Intelligent Information and Communications Technology (IICT) at Konan University and the ORSJ (Operations Research Society of Japan)}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Performance Evaluation of an IPTV Recording Service}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-301 %A Hoßfeld, Tobias %A Leibnitz, Kenji %B Invited Paper at the Jointly-organized Symposium of the Institute of Intelligent Information and Communications Technology (IICT) at Konan University and the ORSJ (Operations Research Society of Japan) %C Kobe, Japan %D 2007 %T Performance Evaluation of an IPTV Recording Service
• Impact of HSDPA Transmit Power Allocation Schemes on the Performance of UMTS Networks. Mäder, Andreas; Staehle, Dirk; Pries, Rastin; Spahn, Markus. In Australasian Telecommunication Networks and Applications Conference 2007. Christchurch, New Zealand, 2007.
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  @inproceedings{info3-inproceedings-2007-298, address = {Christchurch, New Zealand}, author = {Mäder, Andreas and Staehle, Dirk and Pries, Rastin and Spahn, Markus}, booktitle = {Australasian Telecommunication Networks and Applications Conference 2007}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Impact of HSDPA Transmit Power Allocation Schemes on the Performance of UMTS Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-298 %A Mäder, Andreas %A Staehle, Dirk %A Pries, Rastin %A Spahn, Markus %B Australasian Telecommunication Networks and Applications Conference 2007 %C Christchurch, New Zealand %D 2007 %T Impact of HSDPA Transmit Power Allocation Schemes on the Performance of UMTS Networks
• Performance Comparison of Windows-based Thin-Client Architectures. Schlosser, Daniel; Binzenhöfer, Andreas; Staehle, Barbara. In Proc. of the Australasian Telecommunication Networks and Applications Conference 2007. Christchurch, New Zealand, 2007.
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  The basic idea behind thin-client architectures is to run applications on a central server instead of installing them separately on each client. The Windows Remote Desktop Protocol (RDP) and the Citrix Presentation Server are two well known approaches to separate the location of where the user input is processed from the computer he is actually working on. While both alternatives solve the same problem, they rely on significantly different mechanisms to handle the exchange of user input and screen updates between client and server. In this paper we therefore compare the performance of both protocols under different aspects. In particular, we study the load caused on network layer as well as the satisfaction of the end user with the service quality achieved by the different terminal services. As this performance heavily depends on the current network conditions, we emulate realistic scenarios in a controlled testbed environment and measure the time required for typical office tasks on application layer. As a result, we quantify the Quality-of-Experience (QoE) perceived by the end-user, compare the overhead required by the different available protocols, and unveil their advantages and disadvantages. Our results can be used to decide which protocol to use in which scenario.

  @inproceedings{info3-inproceedings-2007-300, abstract = {The basic idea behind thin-client architectures is to run applications on a central server instead of installing them separately on each client. The Windows Remote Desktop Protocol (RDP) and the Citrix Presentation Server are two well known approaches to separate the location of where the user input is processed from the computer he is actually working on. While both alternatives solve the same problem, they rely on significantly different mechanisms to handle the exchange of user input and screen updates between client and server. In this paper we therefore compare the performance of both protocols under different aspects. In particular, we study the load caused on network layer as well as the satisfaction of the end user with the service quality achieved by the different terminal services. As this performance heavily depends on the current network conditions, we emulate realistic scenarios in a controlled testbed environment and measure the time required for typical office tasks on application layer. As a result, we quantify the Quality-of-Experience (QoE) perceived by the end-user, compare the overhead required by the different available protocols, and unveil their advantages and disadvantages. Our results can be used to decide which protocol to use in which scenario.}, address = {Christchurch, New Zealand}, author = {Schlosser, Daniel and Binzenhöfer, Andreas and Staehle, Barbara}, booktitle = {Proc. of the Australasian Telecommunication Networks and Applications Conference 2007}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Performance Comparison of Windows-based Thin-Client Architectures}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-300 %A Schlosser, Daniel %A Binzenhöfer, Andreas %A Staehle, Barbara %B Proc. of the Australasian Telecommunication Networks and Applications Conference 2007 %C Christchurch, New Zealand %D 2007 %T Performance Comparison of Windows-based Thin-Client Architectures %X The basic idea behind thin-client architectures is to run applications on a central server instead of installing them separately on each client. The Windows Remote Desktop Protocol (RDP) and the Citrix Presentation Server are two well known approaches to separate the location of where the user input is processed from the computer he is actually working on. While both alternatives solve the same problem, they rely on significantly different mechanisms to handle the exchange of user input and screen updates between client and server. In this paper we therefore compare the performance of both protocols under different aspects. In particular, we study the load caused on network layer as well as the satisfaction of the end user with the service quality achieved by the different terminal services. As this performance heavily depends on the current network conditions, we emulate realistic scenarios in a controlled testbed environment and measure the time required for typical office tasks on application layer. As a result, we quantify the Quality-of-Experience (QoE) perceived by the end-user, compare the overhead required by the different available protocols, and unveil their advantages and disadvantages. Our results can be used to decide which protocol to use in which scenario.
• A Model for Time-Efficient HSDPA Simulations. Staehle, Dirk; Mäder, Andreas. In IEEE VTC Fall ’07. Baltimore, USA, 2007.
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  @inproceedings{info3-inproceedings-2007-278, address = {Baltimore, USA}, author = {Staehle, Dirk and Mäder, Andreas}, booktitle = {IEEE VTC Fall '07}, keywords = {sys:hidden:inproceedings}, month = 10, title = {A Model for Time-Efficient HSDPA Simulations}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-278 %A Staehle, Dirk %A Mäder, Andreas %B IEEE VTC Fall '07 %C Baltimore, USA %D 2007 %T A Model for Time-Efficient HSDPA Simulations
• Impact of Energy Models on Energy Efficient Sensor Network Routing. Staehle, Barbara; Staehle, Dirk. In 4th IEEE International Conference on Mobile Ad-hoc and Sensor Systems. Pisa, Italy, 2007.
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  Models and proposals for capturing the energy consumption of sensor nodes are plentiful. The majority of those approaches roughly agree about the energy consumed in the states of the sensor node duty cycle, but the costs of radio operations are abstracted very differently. In our work, we establish a general framework whose modular structure allows to compare existing abstractions and to investigate which factors are crucial for the modeling of transmission costs. We analyze the influence of typical assumptions on the creation of energy efficient routing topologies. For this purpose the resulting routing trees are not only compared by topological characteristics, but also by estimating radio related energy consumptions, a metric which changes strongly with the MAC layer efficiency.

  @inproceedings{info3-inproceedings-2007-288, abstract = {Models and proposals for capturing the energy consumption of sensor nodes are plentiful. The majority of those approaches roughly agree about the energy consumed in the states of the sensor node duty cycle, but the costs of radio operations are abstracted very differently. In our work, we establish a general framework whose modular structure allows to compare existing abstractions and to investigate which factors are crucial for the modeling of transmission costs. We analyze the influence of typical assumptions on the creation of energy efficient routing topologies. For this purpose the resulting routing trees are not only compared by topological characteristics, but also by estimating radio related energy consumptions, a metric which changes strongly with the MAC layer efficiency.}, address = {Pisa, Italy}, author = {Staehle, Barbara and Staehle, Dirk}, booktitle = {4th IEEE International Conference on Mobile Ad-hoc and Sensor Systems}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Impact of Energy Models on Energy Efficient Sensor Network Routing}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-288 %A Staehle, Barbara %A Staehle, Dirk %B 4th IEEE International Conference on Mobile Ad-hoc and Sensor Systems %C Pisa, Italy %D 2007 %T Impact of Energy Models on Energy Efficient Sensor Network Routing %X Models and proposals for capturing the energy consumption of sensor nodes are plentiful. The majority of those approaches roughly agree about the energy consumed in the states of the sensor node duty cycle, but the costs of radio operations are abstracted very differently. In our work, we establish a general framework whose modular structure allows to compare existing abstractions and to investigate which factors are crucial for the modeling of transmission costs. We analyze the influence of typical assumptions on the creation of energy efficient routing topologies. For this purpose the resulting routing trees are not only compared by topological characteristics, but also by estimating radio related energy consumptions, a metric which changes strongly with the MAC layer efficiency.
• A Novel Linear-Programming Based Approach for Near-Optimal Rate Allocation in the UMTS Enhanced Uplink. Liu, Tuo; Mäder, Andreas; Staehle, Dirk. In Proc. of IEEE WiMob. White Plains, New York, USA, 2007.
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  @inproceedings{info3-inproceedings-2007-285, address = {White Plains, New York, USA}, author = {Liu, Tuo and Mäder, Andreas and Staehle, Dirk}, booktitle = {Proc. of IEEE WiMob}, keywords = {sys:hidden:inproceedings}, month = 10, title = {A Novel Linear-Programming Based Approach for Near-Optimal Rate Allocation in the UMTS Enhanced Uplink}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-285 %A Liu, Tuo %A Mäder, Andreas %A Staehle, Dirk %B Proc. of IEEE WiMob %C White Plains, New York, USA %D 2007 %T A Novel Linear-Programming Based Approach for Near-Optimal Rate Allocation in the UMTS Enhanced Uplink
• A flow-level Simulation Framework for HSDPA-enabled UMTS Networks. Mäder, Andreas; Staehle, Dirk. In ACM/IEEE MSWiM ’07. Crete, Greece, 2007.
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  @inproceedings{info3-inproceedings-2007-289, address = {Crete, Greece}, author = {Mäder, Andreas and Staehle, Dirk}, booktitle = {ACM/IEEE MSWiM '07}, keywords = {sys:hidden:inproceedings}, month = 10, title = {A flow-level Simulation Framework for HSDPA-enabled UMTS Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-289 %A Mäder, Andreas %A Staehle, Dirk %B ACM/IEEE MSWiM '07 %C Crete, Greece %D 2007 %T A flow-level Simulation Framework for HSDPA-enabled UMTS Networks
• Overview of Resilience Mechanisms Based on Multipath Structures. Menth, Michael; Martin, Rüdiger; Koster, Arie M.C.A.; Orlowski, Sebastian. In The 6th International Workshop on Design of Reliable Communication Networks (DRCN). La Rochelle, France, 2007.
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  @inproceedings{info3-inproceedings-2007-270, address = {La Rochelle, France}, author = {Menth, Michael and Martin, Rüdiger and Koster, Arie M.C.A. and Orlowski, Sebastian}, booktitle = {The 6th International Workshop on Design of Reliable Communication Networks (DRCN)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Overview of Resilience Mechanisms Based on Multipath Structures}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-270 %A Menth, Michael %A Martin, Rüdiger %A Koster, Arie M.C.A. %A Orlowski, Sebastian %B The 6th International Workshop on Design of Reliable Communication Networks (DRCN) %C La Rochelle, France %D 2007 %T Overview of Resilience Mechanisms Based on Multipath Structures
• Analytical Other-Cell Interference Characterization over HSUPA-Enabled Multi-cell UMTS Networks. Liu, Tuo; Mäder, Andreas; Staehle, Dirk. In IEEE VTC Fall ’07. Baltimore, USA, 2007.
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  @inproceedings{info3-inproceedings-2007-279, address = {Baltimore, USA}, author = {Liu, Tuo and Mäder, Andreas and Staehle, Dirk}, booktitle = {IEEE VTC Fall '07}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Analytical Other-Cell Interference Characterization over HSUPA-Enabled Multi-cell UMTS Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-279 %A Liu, Tuo %A Mäder, Andreas %A Staehle, Dirk %B IEEE VTC Fall '07 %C Baltimore, USA %D 2007 %T Analytical Other-Cell Interference Characterization over HSUPA-Enabled Multi-cell UMTS Networks
• Impact of HSDPA Radio Resource Allocation Schemes on the System Performance of UMTS Networks. Mäder, Andreas; Staehle, Dirk; Spahn, Markus. In IEEE VTC Fall ’07. Baltimore, USA, 2007.
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  @inproceedings{info3-inproceedings-2007-277, address = {Baltimore, USA}, author = {Mäder, Andreas and Staehle, Dirk and Spahn, Markus}, booktitle = {IEEE VTC Fall '07}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Impact of HSDPA Radio Resource Allocation Schemes on the System Performance of UMTS Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-277 %A Mäder, Andreas %A Staehle, Dirk %A Spahn, Markus %B IEEE VTC Fall '07 %C Baltimore, USA %D 2007 %T Impact of HSDPA Radio Resource Allocation Schemes on the System Performance of UMTS Networks
• Performance Analysis of the Polling Scheme in IEEE 802.16. Vinel, Alexey; Staehle, Dirk; Pries, Rastin; Ni, Qiang. In Distributed Computer and Communication Networks (DCCN-2007): Theory and Applications. Moskow, Russia, 2007.
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  @inproceedings{info3-inproceedings-2007-297, address = {Moskow, Russia}, author = {Vinel, Alexey and Staehle, Dirk and Pries, Rastin and Ni, Qiang}, booktitle = {Distributed Computer and Communication Networks (DCCN-2007): Theory and Applications}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Performance Analysis of the Polling Scheme in IEEE 802.16}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-297 %A Vinel, Alexey %A Staehle, Dirk %A Pries, Rastin %A Ni, Qiang %B Distributed Computer and Communication Networks (DCCN-2007): Theory and Applications %C Moskow, Russia %D 2007 %T Performance Analysis of the Polling Scheme in IEEE 802.16
• A Statistic-Based Approach towards Routing in Mesh Networks. Klein, Alexander; Tran-Gia, Phuoc. In First IEEE International Workshop on Enabling Technologies and Standards for Wireless Mesh Networking Mechtech, p. 6. Pisa, Italy, 2007.
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  @inproceedings{info3-inproceedings-2007-292, address = {Pisa, Italy}, author = {Klein, Alexander and Tran-Gia, Phuoc}, booktitle = {First IEEE International Workshop on Enabling Technologies and Standards for Wireless Mesh Networking Mechtech}, keywords = {sys:hidden:inproceedings}, month = 10, pages = 6, title = {A Statistic-Based Approach towards Routing in Mesh Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-292 %A Klein, Alexander %A Tran-Gia, Phuoc %B First IEEE International Workshop on Enabling Technologies and Standards for Wireless Mesh Networking Mechtech %C Pisa, Italy %D 2007 %P 6 %T A Statistic-Based Approach towards Routing in Mesh Networks
• Energy Consumption Framework for Wireless Sensor Networks. Klein, Alexander; Tran-Gia, Phuoc. In OPNETWORK 2007, p. 7. Washington D.C., 2007.
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  @inproceedings{info3-inproceedings-2007-293, address = {Washington D.C.}, author = {Klein, Alexander and Tran-Gia, Phuoc}, booktitle = {OPNETWORK 2007}, keywords = {sys:hidden:inproceedings}, month = {08}, pages = 7, title = {Energy Consumption Framework for Wireless Sensor Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-293 %A Klein, Alexander %A Tran-Gia, Phuoc %B OPNETWORK 2007 %C Washington D.C. %D 2007 %P 7 %T Energy Consumption Framework for Wireless Sensor Networks
• Analytic Modeling of the UMTS Enhanced Uplink in Multi-Cell Environments with Volume-Based Best-Effort Traffic. Liu, Tuo; Mäder, Andreas; Staehle, Dirk; Everitt, David. In IEEE ISCIT ’07. Sydney, Australia, 2007.
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  @inproceedings{info3-inproceedings-2007-296, address = {Sydney, Australia}, author = {Liu, Tuo and Mäder, Andreas and Staehle, Dirk and Everitt, David}, booktitle = {IEEE ISCIT '07}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Analytic Modeling of the UMTS Enhanced Uplink in Multi-Cell Environments with Volume-Based Best-Effort Traffic}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-296 %A Liu, Tuo %A Mäder, Andreas %A Staehle, Dirk %A Everitt, David %B IEEE ISCIT '07 %C Sydney, Australia %D 2007 %T Analytic Modeling of the UMTS Enhanced Uplink in Multi-Cell Environments with Volume-Based Best-Effort Traffic
• Estimating Churn in Structured P2P Networks. Binzenhöfer, Andreas; Leibnitz, Kenji. In 20th International Teletraffic Congress (ITC20). Ottawa, Canada, 2007.
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  @inproceedings{info3-inproceedings-2007-261, address = {Ottawa, Canada}, author = {Binzenhöfer, Andreas and Leibnitz, Kenji}, booktitle = {20th International Teletraffic Congress (ITC20)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Estimating Churn in Structured P2P Networks}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-261 %A Binzenhöfer, Andreas %A Leibnitz, Kenji %B 20th International Teletraffic Congress (ITC20) %C Ottawa, Canada %D 2007 %T Estimating Churn in Structured P2P Networks
• Enabling the Sleep Mode in Non-beaconed 802.15.4 Multihop Networks - A Simulative Investigation. Staehle, Barbara; Hoßfeld, Tobias; Kuhnert, Matthias; Vicari, Norbert. In 6. GI/ITG KuVS Fachgespräch Drahtlose Sensornetze. Aachen, Germany, 2007.
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  Large wireless sensor network deployments used for environ- mental monitoring or cargo tracking, require energy efficient mesh topologies. This implies duty cycling of sensor nodes to be coordinated with the routing protocol. Staying in the context of ZigBee, we simulate the combination of the sleep enabled non-beaconed mode of 802.15.4 and AODV routing and compare the duty cycling effects of synchronized and unsynchronized sleep scheduling. We consider two different link layer feedback schemes for AODV, denoted as regular and smooth AODV.

  @inproceedings{info3-inproceedings-2007-286, abstract = {Large wireless sensor network deployments used for environ- mental monitoring or cargo tracking, require energy efficient mesh topologies. This implies duty cycling of sensor nodes to be coordinated with the routing protocol. Staying in the context of ZigBee, we simulate the combination of the sleep enabled non-beaconed mode of 802.15.4 and AODV routing and compare the duty cycling effects of synchronized and unsynchronized sleep scheduling. We consider two different link layer feedback schemes for AODV, denoted as regular and smooth AODV.}, address = {Aachen, Germany}, author = {Staehle, Barbara and Hoßfeld, Tobias and Kuhnert, Matthias and Vicari, Norbert}, booktitle = {6. GI/ITG KuVS Fachgespräch Drahtlose Sensornetze}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Enabling the Sleep Mode in Non-beaconed 802.15.4 Multihop Networks - A Simulative Investigation}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-286 %A Staehle, Barbara %A Hoßfeld, Tobias %A Kuhnert, Matthias %A Vicari, Norbert %B 6. GI/ITG KuVS Fachgespräch Drahtlose Sensornetze %C Aachen, Germany %D 2007 %T Enabling the Sleep Mode in Non-beaconed 802.15.4 Multihop Networks - A Simulative Investigation %X Large wireless sensor network deployments used for environ- mental monitoring or cargo tracking, require energy efficient mesh topologies. This implies duty cycling of sensor nodes to be coordinated with the routing protocol. Staying in the context of ZigBee, we simulate the combination of the sleep enabled non-beaconed mode of 802.15.4 and AODV routing and compare the duty cycling effects of synchronized and unsynchronized sleep scheduling. We consider two different link layer feedback schemes for AODV, denoted as regular and smooth AODV.
• Source Traffic Characterization for Thin Client Based Office Applications. Emmert, Barbara; Binzenhöfer, Andreas; Schlosser, Daniel; Weiß, Markus. In 13th EUNICE Open European Summer School and IFIP TC6.6 Workshop on Dependable and Adaptable Networks and Services. University of Twente, the Netherlands, 2007.
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  A thin client is a small network computer which is used as a remote screen visualizing the output of software applications running on a central server. To provide a seamless service to thin client users the network connection between the client and the server must be dimensioned properly. In this paper we therefore characterize the traffic generated by different types of thin client users when working with popular office applications like Microsoft Word, Excel, or PowerPoint. We analyze the traffic patterns measured in our testbed environment and thus provide a basis for subsequent research studies as well as for administrators to estimate the amount and the characteristics of user generated traffic.

  @inproceedings{info3-inproceedings-2007-282, abstract = {A thin client is a small network computer which is used as a remote screen visualizing the output of software applications running on a central server. To provide a seamless service to thin client users the network connection between the client and the server must be dimensioned properly. In this paper we therefore characterize the traffic generated by different types of thin client users when working with popular office applications like Microsoft Word, Excel, or PowerPoint. We analyze the traffic patterns measured in our testbed environment and thus provide a basis for subsequent research studies as well as for administrators to estimate the amount and the characteristics of user generated traffic.}, address = {University of Twente, the Netherlands}, author = {Emmert, Barbara and Binzenhöfer, Andreas and Schlosser, Daniel and Weiß, Markus}, booktitle = {13th EUNICE Open European Summer School and IFIP TC6.6 Workshop on Dependable and Adaptable Networks and Services}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Source Traffic Characterization for Thin Client Based Office Applications}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-282 %A Emmert, Barbara %A Binzenhöfer, Andreas %A Schlosser, Daniel %A Weiß, Markus %B 13th EUNICE Open European Summer School and IFIP TC6.6 Workshop on Dependable and Adaptable Networks and Services %C University of Twente, the Netherlands %D 2007 %T Source Traffic Characterization for Thin Client Based Office Applications %X A thin client is a small network computer which is used as a remote screen visualizing the output of software applications running on a central server. To provide a seamless service to thin client users the network connection between the client and the server must be dimensioned properly. In this paper we therefore characterize the traffic generated by different types of thin client users when working with popular office applications like Microsoft Word, Excel, or PowerPoint. We analyze the traffic patterns measured in our testbed environment and thus provide a basis for subsequent research studies as well as for administrators to estimate the amount and the characteristics of user generated traffic.
• Handover in Sensor Networks using Statistic-Based Routing. Klein, Alexander; Tran-Gia, Phuoc. In 6. Fachgespräch, p. 4. Aix-La-Chapelle, Germany, 2007.
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  @inproceedings{info3-inproceedings-2007-291, address = {Aix-La-Chapelle, Germany}, author = {Klein, Alexander and Tran-Gia, Phuoc}, booktitle = {6. Fachgespräch}, keywords = {sys:hidden:inproceedings}, month = {07}, pages = 4, title = {Handover in Sensor Networks using Statistic-Based Routing}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-291 %A Klein, Alexander %A Tran-Gia, Phuoc %B 6. Fachgespräch %C Aix-La-Chapelle, Germany %D 2007 %P 4 %T Handover in Sensor Networks using Statistic-Based Routing
• Performance of Internet Services over the UMTS Enhanced Uplink. Mäder, Andreas; Staehle, Dirk; Gößwein, Christian. In Proc. of 1st Workshop on Broadband Wireless Access. Cardiff, Wales, GB, 2007.
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  @inproceedings{info3-inproceedings-2007-287, address = {Cardiff, Wales, GB}, author = {Mäder, Andreas and Staehle, Dirk and Gößwein, Christian}, booktitle = {Proc. of 1st Workshop on Broadband Wireless Access}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Performance of Internet Services over the UMTS Enhanced Uplink}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-287 %A Mäder, Andreas %A Staehle, Dirk %A Gößwein, Christian %B Proc. of 1st Workshop on Broadband Wireless Access %C Cardiff, Wales, GB %D 2007 %T Performance of Internet Services over the UMTS Enhanced Uplink
• Comparative Study of the IEEE 802.16 Random Access Mechanisms. Staehle, Dirk; Pries, Rastin. In 1st Broadband Wireless Access Workshop (BWAWS), pp. 334–339. Cardiff, UK, 2007.
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  The WiMAX technology based on the IEEE802.16 standard is currently the most prospective candidate for broadband wireless access networks. One of the key issues is the design of the MAC layer, in particular the multiple access scheme. The IEEE 802.16 standard specifies different scheduling services with individual mechanisms for accessing the channel on the uplink. The non-real-time polling service and the best-effort service mainly rely on a contention mechanism to submit bandwidth requests to the base station. These two services are currently used for all types of traffic with unknown characteristics, i.e. typically all traffic except for some special VoIP connection with known codec. In this paper, we evaluate and compare the performance of the contention mechanisms for fixed and mobile WiMAX.

  @inproceedings{info3-inproceedings-2007-313, abstract = {The WiMAX technology based on the IEEE802.16 standard is currently the most prospective candidate for broadband wireless access networks. One of the key issues is the design of the MAC layer, in particular the multiple access scheme. The IEEE 802.16 standard specifies different scheduling services with individual mechanisms for accessing the channel on the uplink. The non-real-time polling service and the best-effort service mainly rely on a contention mechanism to submit bandwidth requests to the base station. These two services are currently used for all types of traffic with unknown characteristics, i.e. typically all traffic except for some special VoIP connection with known codec. In this paper, we evaluate and compare the performance of the contention mechanisms for fixed and mobile WiMAX.}, address = {Cardiff, UK}, author = {Staehle, Dirk and Pries, Rastin}, booktitle = {1st Broadband Wireless Access Workshop (BWAWS)}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {334–339}, title = {Comparative Study of the IEEE 802.16 Random Access Mechanisms}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-313 %A Staehle, Dirk %A Pries, Rastin %B 1st Broadband Wireless Access Workshop (BWAWS) %C Cardiff, UK %D 2007 %P 334--339 %T Comparative Study of the IEEE 802.16 Random Access Mechanisms %X The WiMAX technology based on the IEEE802.16 standard is currently the most prospective candidate for broadband wireless access networks. One of the key issues is the design of the MAC layer, in particular the multiple access scheme. The IEEE 802.16 standard specifies different scheduling services with individual mechanisms for accessing the channel on the uplink. The non-real-time polling service and the best-effort service mainly rely on a contention mechanism to submit bandwidth requests to the base station. These two services are currently used for all types of traffic with unknown characteristics, i.e. typically all traffic except for some special VoIP connection with known codec. In this paper, we evaluate and compare the performance of the contention mechanisms for fixed and mobile WiMAX.
• Impact of Vertical Handovers on Cooperative Content Distribution Systems. Duelli, Michael; Hoßfeld, Tobias; Staehle, Dirk. In Seventh IEEE International Conference on Peer-to-Peer Computing (P2P2007), pp. 177–184. Best Student Paper, Galway, Ireland, 2007.
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  In this paper, we evaluate the performance of a P2P-based content distribution system in heterogeneous, wireless networks. The mobile users coordinate each other with cooperation strategies enabled by the multi-source download mechanism, as in eDonkey or BitTorrent. Due to the mobility, vertical handovers between different wireless access technologies are required which may result in transmission delays and IP address changes of the switching peer. Hence, connections among users have to be reestablished and downloading users are requeued at a providing peer’s waiting queue. In detail, we investigate the impact of requeueing with each VHO as well as the use of mechanisms that preserve the IP address and connections beyond VHOs, like MobileIP. Another important phenomenon occurring with VHOs is the abrupt change of the available bandwidth, e.g., from a fast WLAN connection to a rather slow UMTS connection. We evaluate the download times for files by means of simulation while considering different load scenarios in today’s and future network layouts of the B3G network. As a result of the performance evaluation, we derive a new time-based cooperation strategy that counters the impact of mobility. Instead of downloading individual blocks of a file, a user gets a time slot at a providing peer. We show that this leads to a significant performance gain.

  @inproceedings{info3-inproceedings-2007-290, abstract = {In this paper, we evaluate the performance of a P2P-based content distribution system in heterogeneous, wireless networks. The mobile users coordinate each other with cooperation strategies enabled by the multi-source download mechanism, as in eDonkey or BitTorrent. Due to the mobility, vertical handovers between different wireless access technologies are required which may result in transmission delays and IP address changes of the switching peer. Hence, connections among users have to be reestablished and downloading users are requeued at a providing peer’s waiting queue. In detail, we investigate the impact of requeueing with each VHO as well as the use of mechanisms that preserve the IP address and connections beyond VHOs, like MobileIP. Another important phenomenon occurring with VHOs is the abrupt change of the available bandwidth, e.g., from a fast WLAN connection to a rather slow UMTS connection. We evaluate the download times for files by means of simulation while considering different load scenarios in today’s and future network layouts of the B3G network. As a result of the performance evaluation, we derive a new time-based cooperation strategy that counters the impact of mobility. Instead of downloading individual blocks of a file, a user gets a time slot at a providing peer. We show that this leads to a significant performance gain.}, address = {Best Student Paper, Galway, Ireland}, author = {Duelli, Michael and Hoßfeld, Tobias and Staehle, Dirk}, booktitle = {Seventh IEEE International Conference on Peer-to-Peer Computing (P2P2007)}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {177–184}, title = {Impact of Vertical Handovers on Cooperative Content Distribution Systems}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-290 %A Duelli, Michael %A Hoßfeld, Tobias %A Staehle, Dirk %B Seventh IEEE International Conference on Peer-to-Peer Computing (P2P2007) %C Best Student Paper, Galway, Ireland %D 2007 %P 177--184 %T Impact of Vertical Handovers on Cooperative Content Distribution Systems %X In this paper, we evaluate the performance of a P2P-based content distribution system in heterogeneous, wireless networks. The mobile users coordinate each other with cooperation strategies enabled by the multi-source download mechanism, as in eDonkey or BitTorrent. Due to the mobility, vertical handovers between different wireless access technologies are required which may result in transmission delays and IP address changes of the switching peer. Hence, connections among users have to be reestablished and downloading users are requeued at a providing peer’s waiting queue. In detail, we investigate the impact of requeueing with each VHO as well as the use of mechanisms that preserve the IP address and connections beyond VHOs, like MobileIP. Another important phenomenon occurring with VHOs is the abrupt change of the available bandwidth, e.g., from a fast WLAN connection to a rather slow UMTS connection. We evaluate the download times for files by means of simulation while considering different load scenarios in today’s and future network layouts of the B3G network. As a result of the performance evaluation, we derive a new time-based cooperation strategy that counters the impact of mobility. Instead of downloading individual blocks of a file, a user gets a time slot at a providing peer. We show that this leads to a significant performance gain.
• Failure-Specific Self-Protecting Multipaths: Increased Capacity Savings or Overengineering?. Menth, Michael; Martin, Rüdiger; Spörlein, Ulrich. In The 6th International Workshop on Design of Reliable Communication Networks (DRCN). La Rochelle, France, 2007.
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  @inproceedings{info3-inproceedings-2007-271, address = {La Rochelle, France}, author = {Menth, Michael and Martin, Rüdiger and Spörlein, Ulrich}, booktitle = {The 6th International Workshop on Design of Reliable Communication Networks (DRCN)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Failure-Specific Self-Protecting Multipaths: Increased Capacity Savings or Overengineering?}, year = 2007 }

  %0 Conference Paper %1 info3-inproceedings-2007-271 %A Menth, Michael %A Martin, Rüdiger %A Spörlein, Ulrich %B The 6th International Workshop on Design of Reliable Communication Networks (DRCN) %C La Rochelle, France %D 2007 %T Failure-Specific Self-Protecting Multipaths: Increased Capacity Savings or Overengineering?

• Performance of Experience-Based Admission Control in the Presence of Traffic Changes. Milbrandt, Jens; Menth, Michael; Junker, Jan. In Fifth IFIP Networking Conference (NETWORKING 2006). Coimbra, Portugal, 2006.
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  @inproceedings{info3-inproceedings-2006-218, address = {Coimbra, Portugal}, author = {Milbrandt, Jens and Menth, Michael and Junker, Jan}, booktitle = {Fifth IFIP Networking Conference (NETWORKING 2006)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Performance of Experience-Based Admission Control in the Presence of Traffic Changes}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-218 %A Milbrandt, Jens %A Menth, Michael %A Junker, Jan %B Fifth IFIP Networking Conference (NETWORKING 2006) %C Coimbra, Portugal %D 2006 %T Performance of Experience-Based Admission Control in the Presence of Traffic Changes
• QoS Traffic in Wireless LAN Overlapping Cells. Pries, Rastin; Heck, Klaus; Tran-Gia, Phuoc; Wirth, Thomas. In European Wireless 2006. Athen, Greece, 2006.
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  @inproceedings{info3-inproceedings-2006-221, address = {Athen, Greece}, author = {Pries, Rastin and Heck, Klaus and Tran-Gia, Phuoc and Wirth, Thomas}, booktitle = {European Wireless 2006}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {QoS Traffic in Wireless LAN Overlapping Cells}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-221 %A Pries, Rastin %A Heck, Klaus %A Tran-Gia, Phuoc %A Wirth, Thomas %B European Wireless 2006 %C Athen, Greece %D 2006 %T QoS Traffic in Wireless LAN Overlapping Cells
• Throughput Performance of Java Messaging Services Using Sun Java System Message Queue. Henjes, Robert; Menth, Michael; Zepfel, Christian. In Proceedings 20th European Conference on Modelling and Simulation, pp. 684–691. Bonn, Germany, 2006.
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  @inproceedings{info3-inproceedings-2006-234, address = {Bonn, Germany}, author = {Henjes, Robert and Menth, Michael and Zepfel, Christian}, booktitle = {Proceedings 20th European Conference on Modelling and Simulation}, keywords = {dirc}, month = {05}, pages = {684-691}, title = {Throughput Performance of Java Messaging Services Using Sun Java System Message Queue}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-234 %A Henjes, Robert %A Menth, Michael %A Zepfel, Christian %B Proceedings 20th European Conference on Modelling and Simulation %C Bonn, Germany %D 2006 %P 684-691 %T Throughput Performance of Java Messaging Services Using Sun Java System Message Queue
• Evaluation of a Pastry-based P2P Overlay for Supporting Vertical Handover. Hoßfeld, Tobias; Oechsner, Simon; Tutschku, Kurt; Andersen, Frank-Uwe. In IEEE Wireless Communications and Networking Conference, p. 6. Las Vegas, NV, USA, 2006.
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  Vertical handovers (VHO) are expected to be a key feature in Beyond 3G (B3G) networks. This paper presents and evaluates a Pastry-based P2P overlay network for supporting vertical handover in B3G networks. The P2P overlay is used to quickly locate attachment points (APs) for mobile entities and to retrieve rapidly the configuration and coverage information of these APs. The advantage of the P2P-based solution is its distributed nature, its scalability, and its self-organizing capability. The performance of the P2P-based VHO support architecture is evaluated in terms of the search time for APs, the scalability of the algorithm, and for homogenous and heterogeneous network layouts. In addition, the solution is compared with the conventional client/server approach.

  @inproceedings{info3-inproceedings-2006-213, abstract = {Vertical handovers (VHO) are expected to be a key feature in Beyond 3G (B3G) networks. This paper presents and evaluates a Pastry-based P2P overlay network for supporting vertical handover in B3G networks. The P2P overlay is used to quickly locate attachment points (APs) for mobile entities and to retrieve rapidly the configuration and coverage information of these APs. The advantage of the P2P-based solution is its distributed nature, its scalability, and its self-organizing capability. The performance of the P2P-based VHO support architecture is evaluated in terms of the search time for APs, the scalability of the algorithm, and for homogenous and heterogeneous network layouts. In addition, the solution is compared with the conventional client/server approach.}, address = {Las Vegas, NV, USA}, author = {Hoßfeld, Tobias and Oechsner, Simon and Tutschku, Kurt and Andersen, Frank-Uwe}, booktitle = {IEEE Wireless Communications and Networking Conference}, keywords = {sys:hidden:inproceedings}, month = {04}, pages = 6, title = {Evaluation of a Pastry-based P2P Overlay for Supporting Vertical Handover}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-213 %A Hoßfeld, Tobias %A Oechsner, Simon %A Tutschku, Kurt %A Andersen, Frank-Uwe %B IEEE Wireless Communications and Networking Conference %C Las Vegas, NV, USA %D 2006 %P 6 %T Evaluation of a Pastry-based P2P Overlay for Supporting Vertical Handover %X Vertical handovers (VHO) are expected to be a key feature in Beyond 3G (B3G) networks. This paper presents and evaluates a Pastry-based P2P overlay network for supporting vertical handover in B3G networks. The P2P overlay is used to quickly locate attachment points (APs) for mobile entities and to retrieve rapidly the configuration and coverage information of these APs. The advantage of the P2P-based solution is its distributed nature, its scalability, and its self-organizing capability. The performance of the P2P-based VHO support architecture is evaluated in terms of the search time for APs, the scalability of the algorithm, and for homogenous and heterogeneous network layouts. In addition, the solution is compared with the conventional client/server approach.
• Efficient Link Failure Detection and Localization using P2P-Overlay Networks. Emmert, Barbara; Binzenhöfer, Andreas. In The First International Workshop on Dependable and Sustainable Peer-to-Peer Systems in conjunction with The First International Conference on Availability, Reliability and Security. Vienna University of Technology, Austria, 2006.
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  Peer-to-Peer (P2P) networks offer a great potential that goes well beyond simple file-sharing. We present a novel approach for using P2P-overlay networks to ensure a sustainable operation of a distributed system. In particular, we show how to detect and localize the causes of physical link failures using the maintenance traffic of a P2P overlay network. The network monitoring architecture can be set up autonomously thereby reducing both the installation costs and the traffic overhead.

  @inproceedings{info3-inproceedings-2006-216, abstract = {Peer-to-Peer (P2P) networks offer a great potential that goes well beyond simple file-sharing. We present a novel approach for using P2P-overlay networks to ensure a sustainable operation of a distributed system. In particular, we show how to detect and localize the causes of physical link failures using the maintenance traffic of a P2P overlay network. The network monitoring architecture can be set up autonomously thereby reducing both the installation costs and the traffic overhead.}, address = {Vienna University of Technology, Austria}, author = {Emmert, Barbara and Binzenhöfer, Andreas}, booktitle = {The First International Workshop on Dependable and Sustainable Peer-to-Peer Systems in conjunction with The First International Conference on Availability, Reliability and Security}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Efficient Link Failure Detection and Localization using P2P-Overlay Networks}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-216 %A Emmert, Barbara %A Binzenhöfer, Andreas %B The First International Workshop on Dependable and Sustainable Peer-to-Peer Systems in conjunction with The First International Conference on Availability, Reliability and Security %C Vienna University of Technology, Austria %D 2006 %T Efficient Link Failure Detection and Localization using P2P-Overlay Networks %X Peer-to-Peer (P2P) networks offer a great potential that goes well beyond simple file-sharing. We present a novel approach for using P2P-overlay networks to ensure a sustainable operation of a distributed system. In particular, we show how to detect and localize the causes of physical link failures using the maintenance traffic of a P2P overlay network. The network monitoring architecture can be set up autonomously thereby reducing both the installation costs and the traffic overhead.
• Adaptive Bandwidth Allocation: Impact of Routing and Load Balancing on Tunnel Capacity Requirements. Milbrandt, Jens; Humm, Korbinian; Menth, Michael. In 2nd Conference on Next Generation Internet Design and Engineering (NGI 2006). València, Spain, 2006.
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  @inproceedings{info3-inproceedings-2006-222, address = {València, Spain}, author = {Milbrandt, Jens and Humm, Korbinian and Menth, Michael}, booktitle = {2nd Conference on Next Generation Internet Design and Engineering (NGI 2006)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Adaptive Bandwidth Allocation: Impact of Routing and Load Balancing on Tunnel Capacity Requirements}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-222 %A Milbrandt, Jens %A Humm, Korbinian %A Menth, Michael %B 2nd Conference on Next Generation Internet Design and Engineering (NGI 2006) %C València, Spain %D 2006 %T Adaptive Bandwidth Allocation: Impact of Routing and Load Balancing on Tunnel Capacity Requirements
• Backup Capacity Requirements for MPLS Fast Reroute. Martin, Rüdiger; Menth, Michael. In 7. ITG Fachtagung Photonische Netze (VDE). Leipzig, Germany, 2006.
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  @inproceedings{info3-inproceedings-2006-226, address = {Leipzig, Germany}, author = {Martin, Rüdiger and Menth, Michael}, booktitle = {7. ITG Fachtagung Photonische Netze (VDE)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Backup Capacity Requirements for MPLS Fast Reroute}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-226 %A Martin, Rüdiger %A Menth, Michael %B 7. ITG Fachtagung Photonische Netze (VDE) %C Leipzig, Germany %D 2006 %T Backup Capacity Requirements for MPLS Fast Reroute
• Gamma-Approximation for the Waiting Time Distribution Function of the M/G/1-oo Queue. Menth, Michael; Henjes, Robert; Zepfel, Christian; Tran-Gia, Phuoc. In 2nd Conference on Next Generation Internet Design and Engineering. Valencia, Spain, 2006.
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  @inproceedings{info3-inproceedings-2006-231, address = {Valencia, Spain}, author = {Menth, Michael and Henjes, Robert and Zepfel, Christian and Tran-Gia, Phuoc}, booktitle = {2nd Conference on Next Generation Internet Design and Engineering}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Gamma-Approximation for the Waiting Time Distribution Function of the M/G/1-oo Queue}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-231 %A Menth, Michael %A Henjes, Robert %A Zepfel, Christian %A Tran-Gia, Phuoc %B 2nd Conference on Next Generation Internet Design and Engineering %C Valencia, Spain %D 2006 %T Gamma-Approximation for the Waiting Time Distribution Function of the M/G/1-oo Queue
• A Scalable Algorithm to Monitor Chord-based P2P Systems at Runtime. Binzenhöfer, Andreas; Kunzmann, Gerald; Henjes, Robert. In Third International Workshop on Hot Topics in Peer-to-Peer Systems (Hot-P2P) in conjunction with the IEEE International Parallel & Distributed Processing Symposium ( IPDPS 2006). Rhodes Island, Greece, 2006.
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  @inproceedings{info3-inproceedings-2006-212, address = {Rhodes Island, Greece}, author = {Binzenhöfer, Andreas and Kunzmann, Gerald and Henjes, Robert}, booktitle = {Third International Workshop on Hot Topics in Peer-to-Peer Systems (Hot-P2P) in conjunction with the IEEE International Parallel & Distributed Processing Symposium ( IPDPS 2006)}, keywords = {p2pinnop}, month = {04}, title = {A Scalable Algorithm to Monitor Chord-based P2P Systems at Runtime}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-212 %A Binzenhöfer, Andreas %A Kunzmann, Gerald %A Henjes, Robert %B Third International Workshop on Hot Topics in Peer-to-Peer Systems (Hot-P2P) in conjunction with the IEEE International Parallel & Distributed Processing Symposium ( IPDPS 2006) %C Rhodes Island, Greece %D 2006 %T A Scalable Algorithm to Monitor Chord-based P2P Systems at Runtime
• Measurements in a Laboratory UMTS Network with time-varying Loads and different Admission Control Strategies. Mäder, Andreas; Wagner, Bartosz; Hoßfeld, Tobias; Staehle, Dirk; Barth, Hans. In 4th International Workshop on Internet Performance, Simulation, Monitoring and Measurement. Salzburg, Austria, 2006.
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  Most measurement studies in the literature on UMTS focus on scenarios which are set up as ”real” as possible. The focus of this study is the performance and the system behaviour in a nearly ideal laboratory system, such that external influences like other-cell interference or fading are eliminated. We performed experiments on load, throughput and timeliness behaviour with UMTS NodeB hardware of two different brands. The results show different admission control and hardware resource management strategies in high load situations which may impact the performance of applications like voice over IP and the modeling of admission control for dedicated channel radio bearers.

  @inproceedings{info3-inproceedings-2006-215, abstract = {Most measurement studies in the literature on UMTS focus on scenarios which are set up as ”real” as possible. The focus of this study is the performance and the system behaviour in a nearly ideal laboratory system, such that external influences like other-cell interference or fading are eliminated. We performed experiments on load, throughput and timeliness behaviour with UMTS NodeB hardware of two different brands. The results show different admission control and hardware resource management strategies in high load situations which may impact the performance of applications like voice over IP and the modeling of admission control for dedicated channel radio bearers.}, address = {Salzburg, Austria}, author = {Mäder, Andreas and Wagner, Bartosz and Hoßfeld, Tobias and Staehle, Dirk and Barth, Hans}, booktitle = {4th International Workshop on Internet Performance, Simulation, Monitoring and Measurement}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {Measurements in a Laboratory UMTS Network with time-varying Loads and different Admission Control Strategies}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-215 %A Mäder, Andreas %A Wagner, Bartosz %A Hoßfeld, Tobias %A Staehle, Dirk %A Barth, Hans %B 4th International Workshop on Internet Performance, Simulation, Monitoring and Measurement %C Salzburg, Austria %D 2006 %T Measurements in a Laboratory UMTS Network with time-varying Loads and different Admission Control Strategies %X Most measurement studies in the literature on UMTS focus on scenarios which are set up as ”real” as possible. The focus of this study is the performance and the system behaviour in a nearly ideal laboratory system, such that external influences like other-cell interference or fading are eliminated. We performed experiments on load, throughput and timeliness behaviour with UMTS NodeB hardware of two different brands. The results show different admission control and hardware resource management strategies in high load situations which may impact the performance of applications like voice over IP and the modeling of admission control for dedicated channel radio bearers.
• Comparison of Capacity Requirements for the Self-Protecting Multipath and Similar Mechanisms in Resilient Packet Networks. Menth, Michael; Reifert, Andreas; Milbrandt, Jens. In 2nd Conference on Next Generation Internet Design and Engineering (NGI). Valencia, Spain, 2006.
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  @inproceedings{info3-inproceedings-2006-242, address = {Valencia, Spain}, author = {Menth, Michael and Reifert, Andreas and Milbrandt, Jens}, booktitle = {2nd Conference on Next Generation Internet Design and Engineering (NGI)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Comparison of Capacity Requirements for the Self-Protecting Multipath and Similar Mechanisms in Resilient Packet Networks}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-242 %A Menth, Michael %A Reifert, Andreas %A Milbrandt, Jens %B 2nd Conference on Next Generation Internet Design and Engineering (NGI) %C Valencia, Spain %D 2006 %T Comparison of Capacity Requirements for the Self-Protecting Multipath and Similar Mechanisms in Resilient Packet Networks
• On Pollution in eDonkey-like Peer-to-Peer File-Sharing Networks. Leibnitz, Kenji; Hoßfeld, Tobias; Wakamiya, Naoki; Murata, Masayuki. In 13th GI/ITG Conference on Measurement, Modeling, and Evaluation of Computer and Communication Systems, MMB2006. Nürnberg, Germany, 2006.
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  In this paper we propose an analytical model for file diffusion in a peer-to-peer (P2P) file-sharing network based on biological epidemics. During the downloading process, the peer shares the downloaded parts of the file and, thus, contributes to distributing it in the network. This behavior is similar to the spreading of epidemic diseases which is a well researched subject in mathematical biology. With our model we investigate the dynamics of file diffusion focusing on the effects of pollution, e.g. malicious peers sharing corrupted version of the file.

  @inproceedings{info3-inproceedings-2006-207, abstract = {In this paper we propose an analytical model for file diffusion in a peer-to-peer (P2P) file-sharing network based on biological epidemics. During the downloading process, the peer shares the downloaded parts of the file and, thus, contributes to distributing it in the network. This behavior is similar to the spreading of epidemic diseases which is a well researched subject in mathematical biology. With our model we investigate the dynamics of file diffusion focusing on the effects of pollution, e.g. malicious peers sharing corrupted version of the file.}, address = {Nürnberg, Germany}, author = {Leibnitz, Kenji and Hoßfeld, Tobias and Wakamiya, Naoki and Murata, Masayuki}, booktitle = {13th GI/ITG Conference on Measurement, Modeling, and Evaluation of Computer and Communication Systems, MMB2006}, keywords = {p2pfdai}, month = {03}, title = {On Pollution in eDonkey-like Peer-to-Peer File-Sharing Networks}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-207 %A Leibnitz, Kenji %A Hoßfeld, Tobias %A Wakamiya, Naoki %A Murata, Masayuki %B 13th GI/ITG Conference on Measurement, Modeling, and Evaluation of Computer and Communication Systems, MMB2006 %C Nürnberg, Germany %D 2006 %T On Pollution in eDonkey-like Peer-to-Peer File-Sharing Networks %X In this paper we propose an analytical model for file diffusion in a peer-to-peer (P2P) file-sharing network based on biological epidemics. During the downloading process, the peer shares the downloaded parts of the file and, thus, contributes to distributing it in the network. This behavior is similar to the spreading of epidemic diseases which is a well researched subject in mathematical biology. With our model we investigate the dynamics of file diffusion focusing on the effects of pollution, e.g. malicious peers sharing corrupted version of the file.
• Using Kademlia for the Configuration of B3G Radio Access Nodes. Oechsner, Simon; Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe; Caviglione, Luca. In Mobile Peer-to-Peer Computing MP2P’06, in conjunction with the 4th IEEE International Conference on Pervasive Computing and Communications (PerCom’06). Pisa, Italy, 2006.
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  Configuration and management of radio access nodes in Beyond 3G (B3G) networks such as NodeBs, Wireless LAN or WIMAX access points is a complex task that consumes a high amount of resources. Most configuration changes have to be done by an operator, especially when it comes to the adaption of a node to its environment, i.e., the cells surrounding its own. This is an expensive and inflexible method. Moreover, the required manual interference hampers the adaptivity of B3G networks towards topology changes. In this work, we present an architecture that allows for the detection of neighboring cells, thereby enabling an easy or even autonomic configuration of the access nodes. In addition to this, the presented Kademlia-based overlay network enables the storage of information needed for network management, such as configuration data or performance measures.

  @inproceedings{info3-inproceedings-2006-206, abstract = {Configuration and management of radio access nodes in Beyond 3G (B3G) networks such as NodeBs, Wireless LAN or WIMAX access points is a complex task that consumes a high amount of resources. Most configuration changes have to be done by an operator, especially when it comes to the adaption of a node to its environment, i.e., the cells surrounding its own. This is an expensive and inflexible method. Moreover, the required manual interference hampers the adaptivity of B3G networks towards topology changes. In this work, we present an architecture that allows for the detection of neighboring cells, thereby enabling an easy or even autonomic configuration of the access nodes. In addition to this, the presented Kademlia-based overlay network enables the storage of information needed for network management, such as configuration data or performance measures.}, address = {Pisa, Italy}, author = {Oechsner, Simon and Hoßfeld, Tobias and Tutschku, Kurt and Andersen, Frank-Uwe and Caviglione, Luca}, booktitle = {Mobile Peer-to-Peer Computing MP2P'06, in conjunction with the 4th IEEE International Conference on Pervasive Computing and Communications (PerCom'06)}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Using Kademlia for the Configuration of B3G Radio Access Nodes}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-206 %A Oechsner, Simon %A Hoßfeld, Tobias %A Tutschku, Kurt %A Andersen, Frank-Uwe %A Caviglione, Luca %B Mobile Peer-to-Peer Computing MP2P'06, in conjunction with the 4th IEEE International Conference on Pervasive Computing and Communications (PerCom'06) %C Pisa, Italy %D 2006 %T Using Kademlia for the Configuration of B3G Radio Access Nodes %X Configuration and management of radio access nodes in Beyond 3G (B3G) networks such as NodeBs, Wireless LAN or WIMAX access points is a complex task that consumes a high amount of resources. Most configuration changes have to be done by an operator, especially when it comes to the adaption of a node to its environment, i.e., the cells surrounding its own. This is an expensive and inflexible method. Moreover, the required manual interference hampers the adaptivity of B3G networks towards topology changes. In this work, we present an architecture that allows for the detection of neighboring cells, thereby enabling an easy or even autonomic configuration of the access nodes. In addition to this, the presented Kademlia-based overlay network enables the storage of information needed for network management, such as configuration data or performance measures.
• Supporting Vertical Handover by Using a Pastry Peer-to-Peer Overlay Network. Hoßfeld, Tobias; Oechsner, Simon; Tutschku, Kurt; Andersen, Frank-Uwe; Caviglione, Luca. In Mobile Peer-to-Peer Computing MP2P’06, in conjunction with the 4th IEEE International Conference on Pervasive Computing and Communications (PerCom’06). Pisa, Italy, 2006.
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  Vertical handovers (VHO) are expected to be a key feature in Beyond 3G (B3G) networks. This paper presents a Pastry-based P2P overlay network for supporting vertical handover in B3G networks. The P2P overlay is used to quickly locate attachment points (APs) for mobile entities and to rapidly retrieve the configuration and coverage information of these APs. The advantage of the P2P-based solution is its distributed nature, its scalability, and its self-organizing capability.

  @inproceedings{info3-inproceedings-2006-205, abstract = {Vertical handovers (VHO) are expected to be a key feature in Beyond 3G (B3G) networks. This paper presents a Pastry-based P2P overlay network for supporting vertical handover in B3G networks. The P2P overlay is used to quickly locate attachment points (APs) for mobile entities and to rapidly retrieve the configuration and coverage information of these APs. The advantage of the P2P-based solution is its distributed nature, its scalability, and its self-organizing capability.}, address = {Pisa, Italy}, author = {Hoßfeld, Tobias and Oechsner, Simon and Tutschku, Kurt and Andersen, Frank-Uwe and Caviglione, Luca}, booktitle = {Mobile Peer-to-Peer Computing MP2P'06, in conjunction with the 4th IEEE International Conference on Pervasive Computing and Communications (PerCom'06)}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Supporting Vertical Handover by Using a Pastry Peer-to-Peer Overlay Network}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-205 %A Hoßfeld, Tobias %A Oechsner, Simon %A Tutschku, Kurt %A Andersen, Frank-Uwe %A Caviglione, Luca %B Mobile Peer-to-Peer Computing MP2P'06, in conjunction with the 4th IEEE International Conference on Pervasive Computing and Communications (PerCom'06) %C Pisa, Italy %D 2006 %T Supporting Vertical Handover by Using a Pastry Peer-to-Peer Overlay Network %X Vertical handovers (VHO) are expected to be a key feature in Beyond 3G (B3G) networks. This paper presents a Pastry-based P2P overlay network for supporting vertical handover in B3G networks. The P2P overlay is used to quickly locate attachment points (APs) for mobile entities and to rapidly retrieve the configuration and coverage information of these APs. The advantage of the P2P-based solution is its distributed nature, its scalability, and its self-organizing capability.
• Throughput Performance of Java Messaging Services Using FioranoMQ. Henjes, Robert; Menth, Michael; Gehrsitz, Sebastian. In 13th GI/ITG Conference on Measuring, Modelling and Evaluation of Computer and Communication Systems (MMB). Nürnberg, Germany, 2006.
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  @inproceedings{info3-inproceedings-2006-230, address = {Nürnberg, Germany}, author = {Henjes, Robert and Menth, Michael and Gehrsitz, Sebastian}, booktitle = {13th GI/ITG Conference on Measuring, Modelling and Evaluation of Computer and Communication Systems (MMB)}, keywords = {dirc}, month = {03}, title = {Throughput Performance of Java Messaging Services Using FioranoMQ}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-230 %A Henjes, Robert %A Menth, Michael %A Gehrsitz, Sebastian %B 13th GI/ITG Conference on Measuring, Modelling and Evaluation of Computer and Communication Systems (MMB) %C Nürnberg, Germany %D 2006 %T Throughput Performance of Java Messaging Services Using FioranoMQ
• Measurement and Analysis of Skype VoIP Traffic in 3G UMTS Systems. Hoßfeld, Tobias; Binzenhöfer, Andreas; Fiedler, Markus; Tutschku, Kurt. In 4th International Workshop on Internet Performance, Simulation, Monitoring and Measurement (IPS-MoMe 2006). Salzburg, Austria, 2006.
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  Voice-over-IP (VoIP) telephony becomes more and more popular in the wired Internet because of easy-to-use applications with high sound quality like Skype. UMTS operators promise to offer large data rates which should also make VoIP possible in a mobile environment. However, the success of those applications strongly depends on the user perceived voice quality. In this paper, we therefore analyze the achievable and the actual quality of IP-based telephony calls using Skype. This is done performing measurements in both a real UMTS network and a test environment. The latter is used to emulate rate control mechanisms and changing system conditions of UMTS networks. The results show whether Skype over UMTS is able to keep pace with existing mobile telephony systems and how it reacts to different network characteristics. The investigated performance measures comprise the Perceptual Evaluation of Speech Quality (PESQ) to evaluate the voice quality, the packet loss, the inter-packet delay, and the throughput to capture networkbased factors. In this context, the concept of the Network Utility Function (NUF) is applied to describe the impact of the network on the voice quality as perceived by the end-user.

  @inproceedings{info3-inproceedings-2006-217, abstract = {Voice-over-IP (VoIP) telephony becomes more and more popular in the wired Internet because of easy-to-use applications with high sound quality like Skype. UMTS operators promise to offer large data rates which should also make VoIP possible in a mobile environment. However, the success of those applications strongly depends on the user perceived voice quality. In this paper, we therefore analyze the achievable and the actual quality of IP-based telephony calls using Skype. This is done performing measurements in both a real UMTS network and a test environment. The latter is used to emulate rate control mechanisms and changing system conditions of UMTS networks. The results show whether Skype over UMTS is able to keep pace with existing mobile telephony systems and how it reacts to different network characteristics. The investigated performance measures comprise the Perceptual Evaluation of Speech Quality (PESQ) to evaluate the voice quality, the packet loss, the inter-packet delay, and the throughput to capture networkbased factors. In this context, the concept of the Network Utility Function (NUF) is applied to describe the impact of the network on the voice quality as perceived by the end-user.}, address = {Salzburg, Austria}, author = {Hoßfeld, Tobias and Binzenhöfer, Andreas and Fiedler, Markus and Tutschku, Kurt}, booktitle = {4th International Workshop on Internet Performance, Simulation, Monitoring and Measurement (IPS-MoMe 2006)}, keywords = {automon}, month = {02}, title = {Measurement and Analysis of Skype VoIP Traffic in 3G UMTS Systems}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-217 %A Hoßfeld, Tobias %A Binzenhöfer, Andreas %A Fiedler, Markus %A Tutschku, Kurt %B 4th International Workshop on Internet Performance, Simulation, Monitoring and Measurement (IPS-MoMe 2006) %C Salzburg, Austria %D 2006 %T Measurement and Analysis of Skype VoIP Traffic in 3G UMTS Systems %X Voice-over-IP (VoIP) telephony becomes more and more popular in the wired Internet because of easy-to-use applications with high sound quality like Skype. UMTS operators promise to offer large data rates which should also make VoIP possible in a mobile environment. However, the success of those applications strongly depends on the user perceived voice quality. In this paper, we therefore analyze the achievable and the actual quality of IP-based telephony calls using Skype. This is done performing measurements in both a real UMTS network and a test environment. The latter is used to emulate rate control mechanisms and changing system conditions of UMTS networks. The results show whether Skype over UMTS is able to keep pace with existing mobile telephony systems and how it reacts to different network characteristics. The investigated performance measures comprise the Perceptual Evaluation of Speech Quality (PESQ) to evaluate the voice quality, the packet loss, the inter-packet delay, and the throughput to capture networkbased factors. In this context, the concept of the Network Utility Function (NUF) is applied to describe the impact of the network on the voice quality as perceived by the end-user.
• Modeling of Epidemic Diffusion in Peer-to-Peer File-Sharing Networks. Leibnitz, Kenji; Hoßfeld, Tobias; Wakamiya, Naoki; Murata, Masayuki. In The Second International Workshop on Biologically Inspired Approaches to Advanced Information Technology, Bio-ADIT 2006, LNCS 3853. Senri Life Science Center, Osaka, Japan, 2006.
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  In this paper we propose an analytical model for file diffusion in a peer-to-peer (P2P) file-sharing network based on biological epidemics. During the downloading process, the peer shares the downloaded parts of the file and, thus, contributes to distributing it in the network. This behavior is similar to the spreading of epidemic diseases which is a well researched subject in mathematical biology. Unlike other P2P models based on epidemics, we show that steady state assumptions are not sufficient and that the granularity of the diffusion model may be appropriately selected.

  @inproceedings{info3-inproceedings-2006-204, abstract = {In this paper we propose an analytical model for file diffusion in a peer-to-peer (P2P) file-sharing network based on biological epidemics. During the downloading process, the peer shares the downloaded parts of the file and, thus, contributes to distributing it in the network. This behavior is similar to the spreading of epidemic diseases which is a well researched subject in mathematical biology. Unlike other P2P models based on epidemics, we show that steady state assumptions are not sufficient and that the granularity of the diffusion model may be appropriately selected.}, address = {Senri Life Science Center, Osaka, Japan}, author = {Leibnitz, Kenji and Hoßfeld, Tobias and Wakamiya, Naoki and Murata, Masayuki}, booktitle = {The Second International Workshop on Biologically Inspired Approaches to Advanced Information Technology, Bio-ADIT 2006, LNCS 3853}, keywords = {p2pfdai}, month = {01}, title = {Modeling of Epidemic Diffusion in Peer-to-Peer File-Sharing Networks}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-204 %A Leibnitz, Kenji %A Hoßfeld, Tobias %A Wakamiya, Naoki %A Murata, Masayuki %B The Second International Workshop on Biologically Inspired Approaches to Advanced Information Technology, Bio-ADIT 2006, LNCS 3853 %C Senri Life Science Center, Osaka, Japan %D 2006 %T Modeling of Epidemic Diffusion in Peer-to-Peer File-Sharing Networks %X In this paper we propose an analytical model for file diffusion in a peer-to-peer (P2P) file-sharing network based on biological epidemics. During the downloading process, the peer shares the downloaded parts of the file and, thus, contributes to distributing it in the network. This behavior is similar to the spreading of epidemic diseases which is a well researched subject in mathematical biology. Unlike other P2P models based on epidemics, we show that steady state assumptions are not sufficient and that the granularity of the diffusion model may be appropriately selected.
• A P2P-based Framework for Distributed Network Management. Binzenhöfer, Andreas; Tutschku, Kurt; auf dem Graben, Björn; Fiedler, Markus; Arlos, Patrik. In New Trends in Network Architectures and Services, LNCS 3883. Loveno di Menaggio, Como, Italy, 2006.
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  @inproceedings{info3-inproceedings-2006-208, address = {Loveno di Menaggio, Como, Italy}, author = {Binzenhöfer, Andreas and Tutschku, Kurt and auf dem Graben, Björn and Fiedler, Markus and Arlos, Patrik}, booktitle = {New Trends in Network Architectures and Services, LNCS 3883}, keywords = {automon}, title = {A P2P-based Framework for Distributed Network Management}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-208 %A Binzenhöfer, Andreas %A Tutschku, Kurt %A auf dem Graben, Björn %A Fiedler, Markus %A Arlos, Patrik %B New Trends in Network Architectures and Services, LNCS 3883 %C Loveno di Menaggio, Como, Italy %D 2006 %T A P2P-based Framework for Distributed Network Management
• Interference Estimation for the HSDPA Service in Heterogeneous UMTS Networks. Mäder, Andreas; Staehle, Dirk. In EuroNGI Workshop on. Loveno di Menaggio, Como, Italy, 2006.
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  @inproceedings{info3-inproceedings-2006-211, address = {Loveno di Menaggio, Como, Italy}, author = {Mäder, Andreas and Staehle, Dirk}, booktitle = {EuroNGI Workshop on}, keywords = {sys:hidden:inproceedings}, title = {Interference Estimation for the HSDPA Service in Heterogeneous UMTS Networks}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-211 %A Mäder, Andreas %A Staehle, Dirk %B EuroNGI Workshop on %C Loveno di Menaggio, Como, Italy %D 2006 %T Interference Estimation for the HSDPA Service in Heterogeneous UMTS Networks
• Time-Discrete Analysis of the Crawling Strategy in an Optimized Mobile P2P Architecture. Hoßfeld, Tobias; Mäder, Andreas; Tutschku, Kurt; Andersen, Frank-Uwe. In EuroNGI Workshop on. Loveno di Menaggio, Como, Italy, 2006.
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  Mobile networks differ from their wireline counterparts mainly by the high costs for air transmissions and by the mobility of the users. A new entity, denoted as the crawling peer, is suggested in order to optimize the resource mediation mechanism for a mobile P2P file sharing application. In [1], we have investigated the performance of a crawling peer by means of simulations. Now, we show a time-discrete analysis of the crawling peer’s performance in order to investigate different scenarios and to enable parameter-sensitivity studies for further improvements of the crawling peer’s strategy.

  @inproceedings{info3-inproceedings-2006-210, abstract = {Mobile networks differ from their wireline counterparts mainly by the high costs for air transmissions and by the mobility of the users. A new entity, denoted as the crawling peer, is suggested in order to optimize the resource mediation mechanism for a mobile P2P file sharing application. In [1], we have investigated the performance of a crawling peer by means of simulations. Now, we show a time-discrete analysis of the crawling peer’s performance in order to investigate different scenarios and to enable parameter-sensitivity studies for further improvements of the crawling peer’s strategy.}, address = {Loveno di Menaggio, Como, Italy}, author = {Hoßfeld, Tobias and Mäder, Andreas and Tutschku, Kurt and Andersen, Frank-Uwe}, booktitle = {EuroNGI Workshop on}, keywords = {mobileptp}, title = {Time-Discrete Analysis of the Crawling Strategy in an Optimized Mobile P2P Architecture}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-210 %A Hoßfeld, Tobias %A Mäder, Andreas %A Tutschku, Kurt %A Andersen, Frank-Uwe %B EuroNGI Workshop on %C Loveno di Menaggio, Como, Italy %D 2006 %T Time-Discrete Analysis of the Crawling Strategy in an Optimized Mobile P2P Architecture %X Mobile networks differ from their wireline counterparts mainly by the high costs for air transmissions and by the mobility of the users. A new entity, denoted as the crawling peer, is suggested in order to optimize the resource mediation mechanism for a mobile P2P file sharing application. In [1], we have investigated the performance of a crawling peer by means of simulations. Now, we show a time-discrete analysis of the crawling peer’s performance in order to investigate different scenarios and to enable parameter-sensitivity studies for further improvements of the crawling peer’s strategy.
• The Throughput Utility Function: Assessing Network Impact on Mobile Services. Fiedler, Markus; Tutschku, Kurt; Chevul, Stefan; Isaksson, Lennart; Binzenhöfer, Andreas. In New Trends in Network Architectures and Services, LNCS 3883. Loveno di Menaggio, Como, Italy, 2006.
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  @inproceedings{info3-inproceedings-2006-209, address = {Loveno di Menaggio, Como, Italy}, author = {Fiedler, Markus and Tutschku, Kurt and Chevul, Stefan and Isaksson, Lennart and Binzenhöfer, Andreas}, booktitle = {New Trends in Network Architectures and Services, LNCS 3883}, keywords = {automon}, title = {The Throughput Utility Function: Assessing Network Impact on Mobile Services}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-209 %A Fiedler, Markus %A Tutschku, Kurt %A Chevul, Stefan %A Isaksson, Lennart %A Binzenhöfer, Andreas %B New Trends in Network Architectures and Services, LNCS 3883 %C Loveno di Menaggio, Como, Italy %D 2006 %T The Throughput Utility Function: Assessing Network Impact on Mobile Services
• When Do We Need Rate Control for Dedicated Channels in UMTS?. Hoßfeld, Tobias; Mäder, Andreas; Staehle, Dirk. In 2006 IEEE 63rd Vehicular Technology Conference. Melbourne, Australia, 2006.
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  The Universal Mobile Telecommunication System (UMTS) offers rate controlled radio bearers for best effort traffic. The purpose of rate control is to maximize resource utilization and concurrently to provide best-effort users with an acceptable grade-of-service. Due to the user behaviour or the used application of a mobile subscriber we distinguish between two types of best-effort users. The time-based users stay for a certain time within the network and download an arbitrary amount of data. Volume-based users leave the network after they have downloaded a specific data volume. The contribution of this work is an evaluation of time-based and volume-based best-effort traffic over rate-controlled DCHs by analytic means and with a detailed packet-level simulation. The results of both approaches are qualitative equal: while the rate control mechanism works effectively for time-based users and allows any rate, the assigned rates for the volume-based users take values between two extremes, either the minimal or the maximal rate.

  @inproceedings{info3-inproceedings-2006-223, abstract = {The Universal Mobile Telecommunication System (UMTS) offers rate controlled radio bearers for best effort traffic. The purpose of rate control is to maximize resource utilization and concurrently to provide best-effort users with an acceptable grade-of-service. Due to the user behaviour or the used application of a mobile subscriber we distinguish between two types of best-effort users. The time-based users stay for a certain time within the network and download an arbitrary amount of data. Volume-based users leave the network after they have downloaded a specific data volume. The contribution of this work is an evaluation of time-based and volume-based best-effort traffic over rate-controlled DCHs by analytic means and with a detailed packet-level simulation. The results of both approaches are qualitative equal: while the rate control mechanism works effectively for time-based users and allows any rate, the assigned rates for the volume-based users take values between two extremes, either the minimal or the maximal rate.}, address = {Melbourne, Australia}, author = {Hoßfeld, Tobias and Mäder, Andreas and Staehle, Dirk}, booktitle = {2006 IEEE 63rd Vehicular Technology Conference}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {When Do We Need Rate Control for Dedicated Channels in UMTS?}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-223 %A Hoßfeld, Tobias %A Mäder, Andreas %A Staehle, Dirk %B 2006 IEEE 63rd Vehicular Technology Conference %C Melbourne, Australia %D 2006 %T When Do We Need Rate Control for Dedicated Channels in UMTS? %X The Universal Mobile Telecommunication System (UMTS) offers rate controlled radio bearers for best effort traffic. The purpose of rate control is to maximize resource utilization and concurrently to provide best-effort users with an acceptable grade-of-service. Due to the user behaviour or the used application of a mobile subscriber we distinguish between two types of best-effort users. The time-based users stay for a certain time within the network and download an arbitrary amount of data. Volume-based users leave the network after they have downloaded a specific data volume. The contribution of this work is an evaluation of time-based and volume-based best-effort traffic over rate-controlled DCHs by analytic means and with a detailed packet-level simulation. The results of both approaches are qualitative equal: while the rate control mechanism works effectively for time-based users and allows any rate, the assigned rates for the volume-based users take values between two extremes, either the minimal or the maximal rate.
• On the Suitability of the Short Message Service for Emergency Warning Systems. Pries, Rastin; Hoßfeld, Tobias; Tran-Gia, Phuoc. In 2006 IEEE 63rd Vehicular Technology Conference. Melbourne, Australia, 2006.
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  The Global System for Mobile Communications (GSM) is the most popular standard for mobile phones in the world with about 1.57 billion customers. The Short Message Service (SMS) in GSM allows amongst others the transmission of short text messages to mobile phones. In case of an emergency, the SMS can be used to warn a large number of individuals. However, the short message delivery is performed on best-effort basis and no quality of service (QoS) agreement is given, i.e., there is no guarantee how long it takes a message to reach the recipient or that the message will be successfully delivered. In this paper, we investigate the message loss probability and the transmission time by performing measurements with different scenarios in a public GSM network. Then, we identify problems according to the requirements for an emergency warning system. We present a solution based on the cell broadcast in GSM and show numerical results regarding the delay and the capacity of the SMS.

  @inproceedings{info3-inproceedings-2006-220, abstract = {The Global System for Mobile Communications (GSM) is the most popular standard for mobile phones in the world with about 1.57 billion customers. The Short Message Service (SMS) in GSM allows amongst others the transmission of short text messages to mobile phones. In case of an emergency, the SMS can be used to warn a large number of individuals. However, the short message delivery is performed on best-effort basis and no quality of service (QoS) agreement is given, i.e., there is no guarantee how long it takes a message to reach the recipient or that the message will be successfully delivered. In this paper, we investigate the message loss probability and the transmission time by performing measurements with different scenarios in a public GSM network. Then, we identify problems according to the requirements for an emergency warning system. We present a solution based on the cell broadcast in GSM and show numerical results regarding the delay and the capacity of the SMS.}, address = {Melbourne, Australia}, author = {Pries, Rastin and Hoßfeld, Tobias and Tran-Gia, Phuoc}, booktitle = {2006 IEEE 63rd Vehicular Technology Conference}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {On the Suitability of the Short Message Service for Emergency Warning Systems}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-220 %A Pries, Rastin %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %B 2006 IEEE 63rd Vehicular Technology Conference %C Melbourne, Australia %D 2006 %T On the Suitability of the Short Message Service for Emergency Warning Systems %X The Global System for Mobile Communications (GSM) is the most popular standard for mobile phones in the world with about 1.57 billion customers. The Short Message Service (SMS) in GSM allows amongst others the transmission of short text messages to mobile phones. In case of an emergency, the SMS can be used to warn a large number of individuals. However, the short message delivery is performed on best-effort basis and no quality of service (QoS) agreement is given, i.e., there is no guarantee how long it takes a message to reach the recipient or that the message will be successfully delivered. In this paper, we investigate the message loss probability and the transmission time by performing measurements with different scenarios in a public GSM network. Then, we identify problems according to the requirements for an emergency warning system. We present a solution based on the cell broadcast in GSM and show numerical results regarding the delay and the capacity of the SMS.
• Supporting Vertical Handover by a Self-Organizing Multi-Dimensional P2P Overlay. Oechsner, Simon; Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe. In 2006 IEEE 63rd Vehicular Technology Conference. Melbourne, Australia, 2006.
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  Vertical handovers (VHO) are expected to be a key feature in Beyond 3G (B3G) networks. This paper presents a CAN-based P2P overlay network for supporting vertical handover in B3G networks. The P2P overlay is used to quickly locate attachment points (APs) for mobile entities and to retrieve rapidly the configuration and coverage information of these APs. The advantage of the P2P-based solution is its distributed nature, its scalability, and its self-organizing capability. We show by means of simulation the efficiency and the scalability of our approach in comparison to a standard CAN implementation.

  @inproceedings{info3-inproceedings-2006-214, abstract = {Vertical handovers (VHO) are expected to be a key feature in Beyond 3G (B3G) networks. This paper presents a CAN-based P2P overlay network for supporting vertical handover in B3G networks. The P2P overlay is used to quickly locate attachment points (APs) for mobile entities and to retrieve rapidly the configuration and coverage information of these APs. The advantage of the P2P-based solution is its distributed nature, its scalability, and its self-organizing capability. We show by means of simulation the efficiency and the scalability of our approach in comparison to a standard CAN implementation.}, address = {Melbourne, Australia}, author = {Oechsner, Simon and Hoßfeld, Tobias and Tutschku, Kurt and Andersen, Frank-Uwe}, booktitle = {2006 IEEE 63rd Vehicular Technology Conference}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Supporting Vertical Handover by a Self-Organizing Multi-Dimensional P2P Overlay}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-214 %A Oechsner, Simon %A Hoßfeld, Tobias %A Tutschku, Kurt %A Andersen, Frank-Uwe %B 2006 IEEE 63rd Vehicular Technology Conference %C Melbourne, Australia %D 2006 %T Supporting Vertical Handover by a Self-Organizing Multi-Dimensional P2P Overlay %X Vertical handovers (VHO) are expected to be a key feature in Beyond 3G (B3G) networks. This paper presents a CAN-based P2P overlay network for supporting vertical handover in B3G networks. The P2P overlay is used to quickly locate attachment points (APs) for mobile entities and to retrieve rapidly the configuration and coverage information of these APs. The advantage of the P2P-based solution is its distributed nature, its scalability, and its self-organizing capability. We show by means of simulation the efficiency and the scalability of our approach in comparison to a standard CAN implementation.
• An Analytical Model for Best Effort Traffic over the UMTS Enhanced Uplink. Mäder, Andreas; Staehle, Dirk. In Proc. of VTC Fall ’06. Montreal, CA, 2006.
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  @inproceedings{info3-inproceedings-2006-232, address = {Montreal, CA}, author = {Mäder, Andreas and Staehle, Dirk}, booktitle = {Proc. of VTC Fall '06}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {An Analytical Model for Best Effort Traffic over the UMTS Enhanced Uplink}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-232 %A Mäder, Andreas %A Staehle, Dirk %B Proc. of VTC Fall '06 %C Montreal, CA %D 2006 %T An Analytical Model for Best Effort Traffic over the UMTS Enhanced Uplink
• Time-Exponentially Weighted Moving Histograms (TEWMH) for Self-Adaptive Systems. Menth, Michael; Milbrandt, Jens; Junker, Jan. In IEEE Globecom. San Francisco, CA, USA, 2006.
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  @inproceedings{info3-inproceedings-2006-241, address = {San Francisco, CA, USA}, author = {Menth, Michael and Milbrandt, Jens and Junker, Jan}, booktitle = {IEEE Globecom}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Time-Exponentially Weighted Moving Histograms (TEWMH) for Self-Adaptive Systems}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-241 %A Menth, Michael %A Milbrandt, Jens %A Junker, Jan %B IEEE Globecom %C San Francisco, CA, USA %D 2006 %T Time-Exponentially Weighted Moving Histograms (TEWMH) for Self-Adaptive Systems
• Autonomically Improving the Security and Robustness of Structured P2P Overlays. Kunzmann, Gerald; Binzenhöfer, Andreas. In International Conference on Systems and Networks Communications. ICSNC 2006. Tahiti, French Polynesia, 2006.
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  @inproceedings{info3-inproceedings-2006-249, address = {Tahiti, French Polynesia}, author = {Kunzmann, Gerald and Binzenhöfer, Andreas}, booktitle = {International Conference on Systems and Networks Communications. ICSNC 2006}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Autonomically Improving the Security and Robustness of Structured P2P Overlays}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-249 %A Kunzmann, Gerald %A Binzenhöfer, Andreas %B International Conference on Systems and Networks Communications. ICSNC 2006 %C Tahiti, French Polynesia %D 2006 %T Autonomically Improving the Security and Robustness of Structured P2P Overlays
• Impact of Unprotected Multi-Failures in Resilient SPM-Networks: a Capacity Dimensioning Approach. Menth, Michael; Martin, Rüdiger; Spörlein, Ulrich. In IEEE Globecom. San Francisco, CA, USA, 2006.
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  @inproceedings{info3-inproceedings-2006-240, address = {San Francisco, CA, USA}, author = {Menth, Michael and Martin, Rüdiger and Spörlein, Ulrich}, booktitle = {IEEE Globecom}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Impact of Unprotected Multi-Failures in Resilient SPM-Networks: a Capacity Dimensioning Approach}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-240 %A Menth, Michael %A Martin, Rüdiger %A Spörlein, Ulrich %B IEEE Globecom %C San Francisco, CA, USA %D 2006 %T Impact of Unprotected Multi-Failures in Resilient SPM-Networks: a Capacity Dimensioning Approach
• Trunk Reservation Revisited: On Price-Driven Storage Allocation in an Ubiquitous Peer-to-Peer Network Federation. Reichl, Peter; Emmert, Barbara; Bessler, Sandford. In Invited Paper, INFORMS Annual Meeting 2006. Pittsburgh, PA, USA, 2006.
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  @inproceedings{info3-inproceedings-2006-250, address = {Pittsburgh, PA, USA}, author = {Reichl, Peter and Emmert, Barbara and Bessler, Sandford}, booktitle = {Invited Paper, INFORMS Annual Meeting 2006}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Trunk Reservation Revisited: On Price-Driven Storage Allocation in an Ubiquitous Peer-to-Peer Network Federation}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-250 %A Reichl, Peter %A Emmert, Barbara %A Bessler, Sandford %B Invited Paper, INFORMS Annual Meeting 2006 %C Pittsburgh, PA, USA %D 2006 %T Trunk Reservation Revisited: On Price-Driven Storage Allocation in an Ubiquitous Peer-to-Peer Network Federation
• Verlässliche Peer-to-Peer Technologie als Steuerungsverfahren für zukünftige mobile Zugangsnetze. Andersen, Frank-Uwe; Tutschku, Kurt; Hoßfeld, Tobias; Oechsner, Simon. In 11. ITG-Mobilfunktagung, Technologien und Anwendungen, ISBN 3-8007-2942-3. Osnabrück, Germany, 2006.
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  Gegenstand unserer Untersuchung ist der Einsatz von verlässlicher „Peer-to-Peer“ (P2P) Technologie innerhalb Betreiber-eigener Kernnetze mit dem Ziel, eine Dezentralisierung von Steuerungsdiensten zu erreichen. Als Anwendung besonders aussichtsreich erscheint die Unterstützung von Handover-Vorgängen in heterogenen Radio- Zugangsnetzen (z.B. 802.11x und 3G). Während hierfür zwar recht schnell P2P-Lösungen gefunden werden können, die grundsätzlich funktionieren, besteht die Herausforderung darin, die als immanent angenommenen Vorteile von P2P wie Skalierbarkeit, Selbstorganisation und Robustheit den hohen Anforderungen von Betreibern nach „Verlässlichkeit“ gegenüberzustellen, und, wo möglich, die Zuverlässigkeit zu erhöhen. Anhand zweier Beispiele werden solche Optimierungen beschrieben. Als Referenz dienen ein neues Handover-Verfahren für „Beyond 3G“ (B3G) Netze mit heterogenen Funktechniken sowie ein verallgemeinertes, klassisches Netzwerkmanagement in 3G-Netzen.

  @inproceedings{info3-inproceedings-2006-233, abstract = {Gegenstand unserer Untersuchung ist der Einsatz von verlässlicher „Peer-to-Peer“ (P2P) Technologie innerhalb Betreiber-eigener Kernnetze mit dem Ziel, eine Dezentralisierung von Steuerungsdiensten zu erreichen. Als Anwendung besonders aussichtsreich erscheint die Unterstützung von Handover-Vorgängen in heterogenen Radio- Zugangsnetzen (z.B. 802.11x und 3G). Während hierfür zwar recht schnell P2P-Lösungen gefunden werden können, die grundsätzlich funktionieren, besteht die Herausforderung darin, die als immanent angenommenen Vorteile von P2P wie Skalierbarkeit, Selbstorganisation und Robustheit den hohen Anforderungen von Betreibern nach „Verlässlichkeit“ gegenüberzustellen, und, wo möglich, die Zuverlässigkeit zu erhöhen. Anhand zweier Beispiele werden solche Optimierungen beschrieben. Als Referenz dienen ein neues Handover-Verfahren für „Beyond 3G“ (B3G) Netze mit heterogenen Funktechniken sowie ein verallgemeinertes, klassisches Netzwerkmanagement in 3G-Netzen.}, address = {Osnabrück, Germany}, author = {Andersen, Frank-Uwe and Tutschku, Kurt and Hoßfeld, Tobias and Oechsner, Simon}, booktitle = {11. ITG-Mobilfunktagung, Technologien und Anwendungen, ISBN 3-8007-2942-3}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Verlässliche Peer-to-Peer Technologie als Steuerungsverfahren für zukünftige mobile Zugangsnetze}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-233 %A Andersen, Frank-Uwe %A Tutschku, Kurt %A Hoßfeld, Tobias %A Oechsner, Simon %B 11. ITG-Mobilfunktagung, Technologien und Anwendungen, ISBN 3-8007-2942-3 %C Osnabrück, Germany %D 2006 %T Verlässliche Peer-to-Peer Technologie als Steuerungsverfahren für zukünftige mobile Zugangsnetze %X Gegenstand unserer Untersuchung ist der Einsatz von verlässlicher „Peer-to-Peer“ (P2P) Technologie innerhalb Betreiber-eigener Kernnetze mit dem Ziel, eine Dezentralisierung von Steuerungsdiensten zu erreichen. Als Anwendung besonders aussichtsreich erscheint die Unterstützung von Handover-Vorgängen in heterogenen Radio- Zugangsnetzen (z.B. 802.11x und 3G). Während hierfür zwar recht schnell P2P-Lösungen gefunden werden können, die grundsätzlich funktionieren, besteht die Herausforderung darin, die als immanent angenommenen Vorteile von P2P wie Skalierbarkeit, Selbstorganisation und Robustheit den hohen Anforderungen von Betreibern nach „Verlässlichkeit“ gegenüberzustellen, und, wo möglich, die Zuverlässigkeit zu erhöhen. Anhand zweier Beispiele werden solche Optimierungen beschrieben. Als Referenz dienen ein neues Handover-Verfahren für „Beyond 3G“ (B3G) Netze mit heterogenen Funktechniken sowie ein verallgemeinertes, klassisches Netzwerkmanagement in 3G-Netzen.
• Requirements for the One-to-One Backup Option in MPLS Fast Reroute. Martin, Rüdiger; Menth, Michael; Canbolat, Korhan. In IEEE International Conference on Broadband Communication, Networks, and Systems (BROADNETS). San Jose, California, USA, 2006.
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  @inproceedings{info3-inproceedings-2006-225, address = {San Jose, California, USA}, author = {Martin, Rüdiger and Menth, Michael and Canbolat, Korhan}, booktitle = {IEEE International Conference on Broadband Communication, Networks, and Systems (BROADNETS)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Requirements for the One-to-One Backup Option in MPLS Fast Reroute}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-225 %A Martin, Rüdiger %A Menth, Michael %A Canbolat, Korhan %B IEEE International Conference on Broadband Communication, Networks, and Systems (BROADNETS) %C San Jose, California, USA %D 2006 %T Requirements for the One-to-One Backup Option in MPLS Fast Reroute
• Algorithms for Fast Resilience Analysis in IP Networks. Menth, Michael; Milbrandt, Jens; Lehrieder, Frank. In 6th IEEE International Workshop on IP Operations and Management (IPOM). Dublin, Ireland, 2006.
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  @inproceedings{info3-inproceedings-2006-246, address = {Dublin, Ireland}, author = {Menth, Michael and Milbrandt, Jens and Lehrieder, Frank}, booktitle = {6th IEEE International Workshop on IP Operations and Management (IPOM)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Algorithms for Fast Resilience Analysis in IP Networks}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-246 %A Menth, Michael %A Milbrandt, Jens %A Lehrieder, Frank %B 6th IEEE International Workshop on IP Operations and Management (IPOM) %C Dublin, Ireland %D 2006 %T Algorithms for Fast Resilience Analysis in IP Networks
• Accuracy and Dynamics of Hash-Based Load Balancing Algorithms for Multipath Internet Routing. Martin, Rüdiger; Menth, Michael; Hemmkeppler, Michael. In IEEE International Conference on Broadband Communication, Networks, and Systems (BROADNETS). San Jose, California, USA, 2006.
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  @inproceedings{info3-inproceedings-2006-227, address = {San Jose, California, USA}, author = {Martin, Rüdiger and Menth, Michael and Hemmkeppler, Michael}, booktitle = {IEEE International Conference on Broadband Communication, Networks, and Systems (BROADNETS)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Accuracy and Dynamics of Hash-Based Load Balancing Algorithms for Multipath Internet Routing}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-227 %A Martin, Rüdiger %A Menth, Michael %A Hemmkeppler, Michael %B IEEE International Conference on Broadband Communication, Networks, and Systems (BROADNETS) %C San Jose, California, USA %D 2006 %T Accuracy and Dynamics of Hash-Based Load Balancing Algorithms for Multipath Internet Routing
• Risk Assessment of End-to-End Disconnection in IP Networks due to Network Failures. Milbrandt, Jens; Martin, Rüdiger; Menth, Michael; Höhn, Florian. In 6th IEEE International Workshop on IP Operations and Management (IPOM). Dublin, Ireland, 2006.
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  @inproceedings{info3-inproceedings-2006-247, address = {Dublin, Ireland}, author = {Milbrandt, Jens and Martin, Rüdiger and Menth, Michael and Höhn, Florian}, booktitle = {6th IEEE International Workshop on IP Operations and Management (IPOM)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Risk Assessment of End-to-End Disconnection in IP Networks due to Network Failures}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-247 %A Milbrandt, Jens %A Martin, Rüdiger %A Menth, Michael %A Höhn, Florian %B 6th IEEE International Workshop on IP Operations and Management (IPOM) %C Dublin, Ireland %D 2006 %T Risk Assessment of End-to-End Disconnection in IP Networks due to Network Failures
• Experience-Based Admission Control with Type-Specific Overbooking. Milbrandt, Jens; Menth, Michael; Junker, Jan. In 6th IEEE International Workshop on IP Operations and Management (IPOM). Dublin, Ireland, 2006.
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  @inproceedings{info3-inproceedings-2006-248, address = {Dublin, Ireland}, author = {Milbrandt, Jens and Menth, Michael and Junker, Jan}, booktitle = {6th IEEE International Workshop on IP Operations and Management (IPOM)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Experience-Based Admission Control with Type-Specific Overbooking}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-248 %A Milbrandt, Jens %A Menth, Michael %A Junker, Jan %B 6th IEEE International Workshop on IP Operations and Management (IPOM) %C Dublin, Ireland %D 2006 %T Experience-Based Admission Control with Type-Specific Overbooking
• Do we need Header Compression for VoIP in Wireless LANs?. Pries, Rastin; Mäder, Andreas; Staehle, Dirk. In 12th EUNICE Open European Summer School 2006. Stuttgart, Germany, 2006.
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  @inproceedings{info3-inproceedings-2006-243, address = {Stuttgart, Germany}, author = {Pries, Rastin and Mäder, Andreas and Staehle, Dirk}, booktitle = {12th EUNICE Open European Summer School 2006}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Do we need Header Compression for VoIP in Wireless LANs?}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-243 %A Pries, Rastin %A Mäder, Andreas %A Staehle, Dirk %B 12th EUNICE Open European Summer School 2006 %C Stuttgart, Germany %D 2006 %T Do we need Header Compression for VoIP in Wireless LANs?
• Requirements for the Facility Backup Option in MPLS Fast Reroute. Martin, Rüdiger; Menth, Michael; Canbolat, Korhan. In IEEE High Performance Switching and Routing (HPSR). PoznaÅ„, Poland, 2006.
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  @inproceedings{info3-inproceedings-2006-224, address = {PoznaÅ„, Poland}, author = {Martin, Rüdiger and Menth, Michael and Canbolat, Korhan}, booktitle = {IEEE High Performance Switching and Routing (HPSR)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Requirements for the Facility Backup Option in MPLS Fast Reroute}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-224 %A Martin, Rüdiger %A Menth, Michael %A Canbolat, Korhan %B IEEE High Performance Switching and Routing (HPSR) %C PoznaÅ„, Poland %D 2006 %T Requirements for the Facility Backup Option in MPLS Fast Reroute
• Capacity Overprovisioning for Networks with Resilience Requirements. Menth, Michael; Martin, Rüdiger; Charzinski, Joachim. In ACM Sigcomm. Pisa, Italy, 2006.
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  @inproceedings{info3-inproceedings-2006-228, address = {Pisa, Italy}, author = {Menth, Michael and Martin, Rüdiger and Charzinski, Joachim}, booktitle = {ACM Sigcomm}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Capacity Overprovisioning for Networks with Resilience Requirements}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-228 %A Menth, Michael %A Martin, Rüdiger %A Charzinski, Joachim %B ACM Sigcomm %C Pisa, Italy %D 2006 %T Capacity Overprovisioning for Networks with Resilience Requirements
• Throughput Performance of Popular JMS Servers. Menth, Michael; Henjes, Robert; Gehrsitz, Sebastian; Zepfel, Christian. In Joint International Conference on Measurement and Modeling of Computer Systems (SIGMETRICS/Performance). Saint-Malo, France, 2006.
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  @inproceedings{info3-inproceedings-2006-237, address = {Saint-Malo, France}, author = {Menth, Michael and Henjes, Robert and Gehrsitz, Sebastian and Zepfel, Christian}, booktitle = {Joint International Conference on Measurement and Modeling of Computer Systems (SIGMETRICS/Performance)}, keywords = {dirc}, month = {06}, title = {Throughput Performance of Popular JMS Servers}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-237 %A Menth, Michael %A Henjes, Robert %A Gehrsitz, Sebastian %A Zepfel, Christian %B Joint International Conference on Measurement and Modeling of Computer Systems (SIGMETRICS/Performance) %C Saint-Malo, France %D 2006 %T Throughput Performance of Popular JMS Servers
• Network Dimensioning for the Self-Protecting Multipath: A Performance Study. Menth, Michael; Martin, Rüdiger; Spörlein, Ulrich. In IEEE International Conference on Communications (ICC). Istanbul, Turkey, 2006.
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  @inproceedings{info3-inproceedings-2006-229, address = {Istanbul, Turkey}, author = {Menth, Michael and Martin, Rüdiger and Spörlein, Ulrich}, booktitle = {IEEE International Conference on Communications (ICC)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Network Dimensioning for the Self-Protecting Multipath: A Performance Study}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-229 %A Menth, Michael %A Martin, Rüdiger %A Spörlein, Ulrich %B IEEE International Conference on Communications (ICC) %C Istanbul, Turkey %D 2006 %T Network Dimensioning for the Self-Protecting Multipath: A Performance Study
• Analysis of the Message Waiting Time for the FioranoMQ JMS Server. Menth, Michael; Henjes, Robert. In 26th International Conference on Distributed Computing Systems (ICDCS). Lisboa, Portugal, 2006.
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  @inproceedings{info3-inproceedings-2006-235, address = {Lisboa, Portugal}, author = {Menth, Michael and Henjes, Robert}, booktitle = {26th International Conference on Distributed Computing Systems (ICDCS)}, keywords = {dirc}, month = {07}, title = {Analysis of the Message Waiting Time for the FioranoMQ JMS Server}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-235 %A Menth, Michael %A Henjes, Robert %B 26th International Conference on Distributed Computing Systems (ICDCS) %C Lisboa, Portugal %D 2006 %T Analysis of the Message Waiting Time for the FioranoMQ JMS Server
• Throughput Performance of Java Messaging Services Using WebsphereMQ. Henjes, Robert; Menth, Michael; Zepfel, Christian. In 5th International Workshop on Distributed Event-Based Systems (DEBS). Lisboa, Portugal, 2006.
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  @inproceedings{info3-inproceedings-2006-236, address = {Lisboa, Portugal}, author = {Henjes, Robert and Menth, Michael and Zepfel, Christian}, booktitle = {5th International Workshop on Distributed Event-Based Systems (DEBS)}, keywords = {dirc}, month = {07}, title = {Throughput Performance of Java Messaging Services Using WebsphereMQ}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-236 %A Henjes, Robert %A Menth, Michael %A Zepfel, Christian %B 5th International Workshop on Distributed Event-Based Systems (DEBS) %C Lisboa, Portugal %D 2006 %T Throughput Performance of Java Messaging Services Using WebsphereMQ
• Performance Study of the WiMAX FDD Mode. Klein, Alexander; Pries, Rastin; Staehle, Dirk. In OPNETWORK 2006. Washington D.C., USA, 2006.
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  @inproceedings{info3-inproceedings-2006-245, address = {Washington D.C., USA}, author = {Klein, Alexander and Pries, Rastin and Staehle, Dirk}, booktitle = {OPNETWORK 2006}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Performance Study of the WiMAX FDD Mode}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-245 %A Klein, Alexander %A Pries, Rastin %A Staehle, Dirk %B OPNETWORK 2006 %C Washington D.C., USA %D 2006 %T Performance Study of the WiMAX FDD Mode
• A Network Architecture for a Policy-Based Handover Across Heterogeneous Networks. Pries, Rastin; Mäder, Andreas; Staehle, Dirk. In OPNETWORK 2006. Washington D.C., USA, 2006.
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  @inproceedings{info3-inproceedings-2006-244, address = {Washington D.C., USA}, author = {Pries, Rastin and Mäder, Andreas and Staehle, Dirk}, booktitle = {OPNETWORK 2006}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {A Network Architecture for a Policy-Based Handover Across Heterogeneous Networks}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-244 %A Pries, Rastin %A Mäder, Andreas %A Staehle, Dirk %B OPNETWORK 2006 %C Washington D.C., USA %D 2006 %T A Network Architecture for a Policy-Based Handover Across Heterogeneous Networks
• Comparison of Robust Cooperation Strategies for P2P Content Distribution Networks with Multiple Source Download. Schlosser, Daniel; Hoßfeld, Tobias; Tutschku, Kurt. In Sixth IEEE International Conference on Peer-to-Peer Computing (P2P2006). Cambridge, UK, 2006.
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  The performance of Peer-to-Peer (P2P) content distribution networks depends highly on the coordination of the peers. Sophisticated cooperation strategies, such as the multiple source download, are the foundation for efficient file exchange. The detailed performance of the strategies are determined by the peer characteristics and the peer behaviour, such as the number of parallel upload connections, the selfishness, or the altruistic re-distribution of data. The purpose of this work is to evaluate and investigate different cooperation strategies for multiple source download and select the best one for a scenario for even leeching peers, i.e. peers which depart as soon as they have finished their download. The question arises whether the cooperation strategy can smoothen the overall performance degradation caused by a selfish peer behaviour. As performance indicator the evolution of the numbers of copies of a chunk and the experienced download times of files is applied. The considered scenarios comprise best-case (altruistic peers) and worst-case scenarios (selfish peers). We further propose a new cooperation strategy to improve the file transfer even when mainly selfish peers are present, the CygPriM (cyclic priority masking) strategy. The strategy allows an efficient P2P based content distribution using ordered chunk delivery with only local information available at a peer.

  @inproceedings{info3-inproceedings-2006-239, abstract = {The performance of Peer-to-Peer (P2P) content distribution networks depends highly on the coordination of the peers. Sophisticated cooperation strategies, such as the multiple source download, are the foundation for efficient file exchange. The detailed performance of the strategies are determined by the peer characteristics and the peer behaviour, such as the number of parallel upload connections, the selfishness, or the altruistic re-distribution of data. The purpose of this work is to evaluate and investigate different cooperation strategies for multiple source download and select the best one for a scenario for even leeching peers, i.e. peers which depart as soon as they have finished their download. The question arises whether the cooperation strategy can smoothen the overall performance degradation caused by a selfish peer behaviour. As performance indicator the evolution of the numbers of copies of a chunk and the experienced download times of files is applied. The considered scenarios comprise best-case (altruistic peers) and worst-case scenarios (selfish peers). We further propose a new cooperation strategy to improve the file transfer even when mainly selfish peers are present, the CygPriM (cyclic priority masking) strategy. The strategy allows an efficient P2P based content distribution using ordered chunk delivery with only local information available at a peer.}, address = {Cambridge, UK}, author = {Schlosser, Daniel and Hoßfeld, Tobias and Tutschku, Kurt}, booktitle = {Sixth IEEE International Conference on Peer-to-Peer Computing (P2P2006)}, keywords = {redlarf}, month = {09}, title = {Comparison of Robust Cooperation Strategies for P2P Content Distribution Networks with Multiple Source Download}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-239 %A Schlosser, Daniel %A Hoßfeld, Tobias %A Tutschku, Kurt %B Sixth IEEE International Conference on Peer-to-Peer Computing (P2P2006) %C Cambridge, UK %D 2006 %T Comparison of Robust Cooperation Strategies for P2P Content Distribution Networks with Multiple Source Download %X The performance of Peer-to-Peer (P2P) content distribution networks depends highly on the coordination of the peers. Sophisticated cooperation strategies, such as the multiple source download, are the foundation for efficient file exchange. The detailed performance of the strategies are determined by the peer characteristics and the peer behaviour, such as the number of parallel upload connections, the selfishness, or the altruistic re-distribution of data. The purpose of this work is to evaluate and investigate different cooperation strategies for multiple source download and select the best one for a scenario for even leeching peers, i.e. peers which depart as soon as they have finished their download. The question arises whether the cooperation strategy can smoothen the overall performance degradation caused by a selfish peer behaviour. As performance indicator the evolution of the numbers of copies of a chunk and the experienced download times of files is applied. The considered scenarios comprise best-case (altruistic peers) and worst-case scenarios (selfish peers). We further propose a new cooperation strategy to improve the file transfer even when mainly selfish peers are present, the CygPriM (cyclic priority masking) strategy. The strategy allows an efficient P2P based content distribution using ordered chunk delivery with only local information available at a peer.
• Prepaid Peer-to-Peer Services. Emmert, Barbara; Jorns, Oliver. In 6th IEEE International Conference on Peer-to-Peer Computing. Cambridge, UK, 2006.
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  Since the early days of file sharing, the quest for incentives persuading users to contribute resources to P2P networks exists. Crediting and debiting users’ accounts for consumptions and contributions is surely one possibility. But how to do this without enormous additional overhead or infrastructure? We depict a solution to this question by describing the establishment of a lightweight, secure prepaid charging mechanism within a P2P network.

  @inproceedings{info3-inproceedings-2006-238, abstract = {Since the early days of file sharing, the quest for incentives persuading users to contribute resources to P2P networks exists. Crediting and debiting users’ accounts for consumptions and contributions is surely one possibility. But how to do this without enormous additional overhead or infrastructure? We depict a solution to this question by describing the establishment of a lightweight, secure prepaid charging mechanism within a P2P network.}, address = {Cambridge, UK}, author = {Emmert, Barbara and Jorns, Oliver}, booktitle = {6th IEEE International Conference on Peer-to-Peer Computing}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Prepaid Peer-to-Peer Services}, year = 2006 }

  %0 Conference Paper %1 info3-inproceedings-2006-238 %A Emmert, Barbara %A Jorns, Oliver %B 6th IEEE International Conference on Peer-to-Peer Computing %C Cambridge, UK %D 2006 %T Prepaid Peer-to-Peer Services %X Since the early days of file sharing, the quest for incentives persuading users to contribute resources to P2P networks exists. Crediting and debiting users’ accounts for consumptions and contributions is surely one possibility. But how to do this without enormous additional overhead or infrastructure? We depict a solution to this question by describing the establishment of a lightweight, secure prepaid charging mechanism within a P2P network.

• Adaptive Bandwidth Allocation: Concepts and Efficiency for Admission-Controlled Capacity Tunnels. Milbrandt, Jens; Menth, Michael; Kopf, Stefan. In 3rd International Conference on Computing, Communications and Control Technologies (CCCT ’05). Austin, Texas, USA, 2005.
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  @inproceedings{info3-inproceedings-2005-195, address = {Austin, Texas, USA}, author = {Milbrandt, Jens and Menth, Michael and Kopf, Stefan}, booktitle = {3rd International Conference on Computing, Communications and Control Technologies (CCCT '05)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Adaptive Bandwidth Allocation: Concepts and Efficiency for Admission-Controlled Capacity Tunnels}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-195 %A Milbrandt, Jens %A Menth, Michael %A Kopf, Stefan %B 3rd International Conference on Computing, Communications and Control Technologies (CCCT '05) %C Austin, Texas, USA %D 2005 %T Adaptive Bandwidth Allocation: Concepts and Efficiency for Admission-Controlled Capacity Tunnels
• A Hybrid Model of the UMTS Downlink Capacity with WWW Traffic on Dedicated Channels. Hoßfeld, Tobias; Staehle, Dirk. In Mobile and Wireless Systems, LNCS 3427, pp. 20–35. Dagstuhl, Germany, 2005.
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  One of the main advances of 3G networks like UMTS is the ability to support a large variety of different services. These services are subdivided in two domains, circuit-switched services and packet-switched services. The main application expected for packet-switched services is the browsing of the World Wide Web. The web traffic is usually described by quite sophisticated source traffic models and the packet arrivals on IP layer are determined by TCP. On the other hand, the planning process for UMTS networks relies on analytic methods or Monte Carlo simulations that assume the number of users to be Poisson distributed. The intention of this work is to examine if it is possible to apply the existing planning methods to web traffic. We are able to show that the Poisson assumption holds for the number of web users that simultaneously transmit over the air interface and that the resulting NodeB transmit power distribution is valid. We use the Monte Carlo simulation technique to evaluate the web capacity of an example UMTS network.

  @inproceedings{info3-inproceedings-2005-159, abstract = {One of the main advances of 3G networks like UMTS is the ability to support a large variety of different services. These services are subdivided in two domains, circuit-switched services and packet-switched services. The main application expected for packet-switched services is the browsing of the World Wide Web. The web traffic is usually described by quite sophisticated source traffic models and the packet arrivals on IP layer are determined by TCP. On the other hand, the planning process for UMTS networks relies on analytic methods or Monte Carlo simulations that assume the number of users to be Poisson distributed. The intention of this work is to examine if it is possible to apply the existing planning methods to web traffic. We are able to show that the Poisson assumption holds for the number of web users that simultaneously transmit over the air interface and that the resulting NodeB transmit power distribution is valid. We use the Monte Carlo simulation technique to evaluate the web capacity of an example UMTS network.}, address = {Dagstuhl, Germany}, author = {Hoßfeld, Tobias and Staehle, Dirk}, booktitle = {Mobile and Wireless Systems, LNCS 3427}, keywords = {sys:hidden:inproceedings}, month = {01}, pages = {20-35}, title = {A Hybrid Model of the UMTS Downlink Capacity with WWW Traffic on Dedicated Channels}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-159 %A Hoßfeld, Tobias %A Staehle, Dirk %B Mobile and Wireless Systems, LNCS 3427 %C Dagstuhl, Germany %D 2005 %P 20-35 %T A Hybrid Model of the UMTS Downlink Capacity with WWW Traffic on Dedicated Channels %X One of the main advances of 3G networks like UMTS is the ability to support a large variety of different services. These services are subdivided in two domains, circuit-switched services and packet-switched services. The main application expected for packet-switched services is the browsing of the World Wide Web. The web traffic is usually described by quite sophisticated source traffic models and the packet arrivals on IP layer are determined by TCP. On the other hand, the planning process for UMTS networks relies on analytic methods or Monte Carlo simulations that assume the number of users to be Poisson distributed. The intention of this work is to examine if it is possible to apply the existing planning methods to web traffic. We are able to show that the Poisson assumption holds for the number of web users that simultaneously transmit over the air interface and that the resulting NodeB transmit power distribution is valid. We use the Monte Carlo simulation technique to evaluate the web capacity of an example UMTS network.
• Mapping of File-Sharing onto Mobile Environments: Feasibility and Performance of eDonkey with GPRS. Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe. In WCNC 2005. New Orleans, LA USA, 2005.
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  @inproceedings{info3-inproceedings-2005-156, address = {New Orleans, LA USA}, author = {Hoßfeld, Tobias and Tutschku, Kurt and Andersen, Frank-Uwe}, booktitle = {WCNC 2005}, keywords = {mobileptp}, month = {03}, title = {Mapping of File-Sharing onto Mobile Environments: Feasibility and Performance of eDonkey with GPRS}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-156 %A Hoßfeld, Tobias %A Tutschku, Kurt %A Andersen, Frank-Uwe %B WCNC 2005 %C New Orleans, LA USA %D 2005 %T Mapping of File-Sharing onto Mobile Environments: Feasibility and Performance of eDonkey with GPRS
• Mapping of File-Sharing onto Mobile Environments: Enhancement by UMTS. Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe. In Mobile Peer-to-Peer Computing MP2P, in conjunction with the 3rd IEEE International Conference on Pervasive Computing and Communications (PerCom’05). Kauai Island, Hawaii, 2005.
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  Peer-to-Peer (P2P) file-sharing has become a major application in the Internet with respect to traffic volume which is even surpassing web usage. This characteristic makes P2P commercially attractive to network operators interested in increased traffic. In parallel, the demand for wireless services has caused wireless networks to grow enormously. We assume that P2P file-sharing will be mapped onto mobile environments by its users. This results in a mobile P2P file-sharing service, which we denote as mobile P2P. In this paper, we examine the feasibility of the eDonkey file-sharing service in GPRS networks, detect problems of the interaction between P2P and the mobile network, and find solutions to overcome them. Furthermore, this paper measures and analyzes the characteristics of mobile P2P and gives first empirical performance values. Summarizing, the goal is the analysis of feasibility for an Internet-based filesharing application in a mobile network and to provide first measurements from two real-world networks.

  @inproceedings{info3-inproceedings-2005-157, abstract = {Peer-to-Peer (P2P) file-sharing has become a major application in the Internet with respect to traffic volume which is even surpassing web usage. This characteristic makes P2P commercially attractive to network operators interested in increased traffic. In parallel, the demand for wireless services has caused wireless networks to grow enormously. We assume that P2P file-sharing will be mapped onto mobile environments by its users. This results in a mobile P2P file-sharing service, which we denote as mobile P2P. In this paper, we examine the feasibility of the eDonkey file-sharing service in GPRS networks, detect problems of the interaction between P2P and the mobile network, and find solutions to overcome them. Furthermore, this paper measures and analyzes the characteristics of mobile P2P and gives first empirical performance values. Summarizing, the goal is the analysis of feasibility for an Internet-based filesharing application in a mobile network and to provide first measurements from two real-world networks.}, address = {Kauai Island, Hawaii}, author = {Hoßfeld, Tobias and Tutschku, Kurt and Andersen, Frank-Uwe}, booktitle = {Mobile Peer-to-Peer Computing MP2P, in conjunction with the 3rd IEEE International Conference on Pervasive Computing and Communications (PerCom'05)}, keywords = {mobileptp}, month = {03}, title = {Mapping of File-Sharing onto Mobile Environments: Enhancement by UMTS}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-157 %A Hoßfeld, Tobias %A Tutschku, Kurt %A Andersen, Frank-Uwe %B Mobile Peer-to-Peer Computing MP2P, in conjunction with the 3rd IEEE International Conference on Pervasive Computing and Communications (PerCom'05) %C Kauai Island, Hawaii %D 2005 %T Mapping of File-Sharing onto Mobile Environments: Enhancement by UMTS %X Peer-to-Peer (P2P) file-sharing has become a major application in the Internet with respect to traffic volume which is even surpassing web usage. This characteristic makes P2P commercially attractive to network operators interested in increased traffic. In parallel, the demand for wireless services has caused wireless networks to grow enormously. We assume that P2P file-sharing will be mapped onto mobile environments by its users. This results in a mobile P2P file-sharing service, which we denote as mobile P2P. In this paper, we examine the feasibility of the eDonkey file-sharing service in GPRS networks, detect problems of the interaction between P2P and the mobile network, and find solutions to overcome them. Furthermore, this paper measures and analyzes the characteristics of mobile P2P and gives first empirical performance values. Summarizing, the goal is the analysis of feasibility for an Internet-based filesharing application in a mobile network and to provide first measurements from two real-world networks.
• Influence of the Size of Swapping Entities in Mobile P2P File-Sharing Networks. Hoßfeld, Tobias; Tutschku, Kurt; Schlosser, Daniel. In Peer-to-Peer-Systeme und -Anwendungen. GI/ITG-Workshop in Kooperation mit KiVS 2005, Kaiserslautern, 2005.
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  Peer-to-Peer (P2P) file-sharing has become the killer application in the wired Internet and might also be highly attractive for mobile networks. In particular since UMTS operators are searching for new applications which do both: a) exploit the potential of the UMTS technology and b) motivate the user to adopt the new technology. Mobile networks differ from wireline networks mainly by the limited capacity of the radio link, the mobility of the users, and the anticipated content exchanged in these networks. P2P networks, in contrast, are overlays which run on top of a transport network. They consider the transport network only in an abstract way. P2P performance is typically considered on overlay level only. In a mobile environment, the question arises, whether the abstraction can be maintained for underlying mobile transport networks, too, and whether there will be a performance impact. In this paper we investigate the performance of a multiple source download mechanism as used in the popular eDonkey file-sharing network. The performance of the proposed mobile P2P architecture has already been considered for several factors, like the capacity of the mobile access network, the mobility of the users, the application of the cache peer, and the size of typical contents of mobile users such as ring tones, images, and mp3 audio files. However, the performance may be increased by adapting the size of the swapping entities in dependence on these main influence factors. The swapping entities are the smallest units for uploading and downloading user data and are called chunks and blocks, respectively. In this work, we show if and how the swapping entities influence the entire system.

  @inproceedings{info3-inproceedings-2005-158, abstract = {Peer-to-Peer (P2P) file-sharing has become the killer application in the wired Internet and might also be highly attractive for mobile networks. In particular since UMTS operators are searching for new applications which do both: a) exploit the potential of the UMTS technology and b) motivate the user to adopt the new technology. Mobile networks differ from wireline networks mainly by the limited capacity of the radio link, the mobility of the users, and the anticipated content exchanged in these networks. P2P networks, in contrast, are overlays which run on top of a transport network. They consider the transport network only in an abstract way. P2P performance is typically considered on overlay level only. In a mobile environment, the question arises, whether the abstraction can be maintained for underlying mobile transport networks, too, and whether there will be a performance impact. In this paper we investigate the performance of a multiple source download mechanism as used in the popular eDonkey file-sharing network. The performance of the proposed mobile P2P architecture has already been considered for several factors, like the capacity of the mobile access network, the mobility of the users, the application of the cache peer, and the size of typical contents of mobile users such as ring tones, images, and mp3 audio files. However, the performance may be increased by adapting the size of the swapping entities in dependence on these main influence factors. The swapping entities are the smallest units for uploading and downloading user data and are called chunks and blocks, respectively. In this work, we show if and how the swapping entities influence the entire system.}, address = {GI/ITG-Workshop in Kooperation mit KiVS 2005, Kaiserslautern}, author = {Hoßfeld, Tobias and Tutschku, Kurt and Schlosser, Daniel}, booktitle = {Peer-to-Peer-Systeme und -Anwendungen}, keywords = {mobileptp}, month = {03}, title = {Influence of the Size of Swapping Entities in Mobile P2P File-Sharing Networks}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-158 %A Hoßfeld, Tobias %A Tutschku, Kurt %A Schlosser, Daniel %B Peer-to-Peer-Systeme und -Anwendungen %C GI/ITG-Workshop in Kooperation mit KiVS 2005, Kaiserslautern %D 2005 %T Influence of the Size of Swapping Entities in Mobile P2P File-Sharing Networks %X Peer-to-Peer (P2P) file-sharing has become the killer application in the wired Internet and might also be highly attractive for mobile networks. In particular since UMTS operators are searching for new applications which do both: a) exploit the potential of the UMTS technology and b) motivate the user to adopt the new technology. Mobile networks differ from wireline networks mainly by the limited capacity of the radio link, the mobility of the users, and the anticipated content exchanged in these networks. P2P networks, in contrast, are overlays which run on top of a transport network. They consider the transport network only in an abstract way. P2P performance is typically considered on overlay level only. In a mobile environment, the question arises, whether the abstraction can be maintained for underlying mobile transport networks, too, and whether there will be a performance impact. In this paper we investigate the performance of a multiple source download mechanism as used in the popular eDonkey file-sharing network. The performance of the proposed mobile P2P architecture has already been considered for several factors, like the capacity of the mobile access network, the mobility of the users, the application of the cache peer, and the size of typical contents of mobile users such as ring tones, images, and mp3 audio files. However, the performance may be increased by adapting the size of the swapping entities in dependence on these main influence factors. The swapping entities are the smallest units for uploading and downloading user data and are called chunks and blocks, respectively. In this work, we show if and how the swapping entities influence the entire system.
• DNA: A p2p-based Framework for Distributed Network Management. Binzenhöfer, Andreas; Tutschku, Kurt; auf dem Graben, Björn. In Peer-to-Peer-Systeme und -Anwendungen. GI/ITG-Workshop in Kooperation mit KiVS 2005, Kaiserslautern, 2005.
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  @inproceedings{info3-inproceedings-2005-160, address = {GI/ITG-Workshop in Kooperation mit KiVS 2005, Kaiserslautern}, author = {Binzenhöfer, Andreas and Tutschku, Kurt and auf dem Graben, Björn}, booktitle = {Peer-to-Peer-Systeme und -Anwendungen}, keywords = {automon}, month = {03}, title = {DNA: A p2p-based Framework for Distributed Network Management}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-160 %A Binzenhöfer, Andreas %A Tutschku, Kurt %A auf dem Graben, Björn %B Peer-to-Peer-Systeme und -Anwendungen %C GI/ITG-Workshop in Kooperation mit KiVS 2005, Kaiserslautern %D 2005 %T DNA: A p2p-based Framework for Distributed Network Management
• Simulative Performance Evaluation of a Mobile Peer-to-Peer File-Sharing System. Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe; de Meer, Hermann; Oberender, Jens. In Next Generation Internet Networks NGI2005. Rome, Italy, 2005.
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  Peer-to-Peer (P2P) file-sharing has become the killer application in the wired Internet and might also be highly attractive for mobile networks. In particular since UMTS operators are searching for new applications which do both: a) exploit the potential of the UMTS technology and b) motivate the user to adopt the new technology. In this work we are investigating the performance of an eDonkey-based mobile P2P file-sharing system by means of time-dynamic simulation. Mobile networks differ from wireline networks by the limited capacity of the radio link and the mobility of the users. P2P networks, in contrast, are overlays which consider the transport network in an abstract way. In a mobile environment, the question arises, whether the abstraction can be maintained and what will be the performance impact if there is any. We will show in detail how the mobile access technology (GPRS or UMTS), the churn behavior of mobile users, the file size of mobile specific content, and special infrastructure entities, such as a cache peer, influences the performance of the suggested mobile P2P file-sharing service.

  @inproceedings{info3-inproceedings-2005-164, abstract = {Peer-to-Peer (P2P) file-sharing has become the killer application in the wired Internet and might also be highly attractive for mobile networks. In particular since UMTS operators are searching for new applications which do both: a) exploit the potential of the UMTS technology and b) motivate the user to adopt the new technology. In this work we are investigating the performance of an eDonkey-based mobile P2P file-sharing system by means of time-dynamic simulation. Mobile networks differ from wireline networks by the limited capacity of the radio link and the mobility of the users. P2P networks, in contrast, are overlays which consider the transport network in an abstract way. In a mobile environment, the question arises, whether the abstraction can be maintained and what will be the performance impact if there is any. We will show in detail how the mobile access technology (GPRS or UMTS), the churn behavior of mobile users, the file size of mobile specific content, and special infrastructure entities, such as a cache peer, influences the performance of the suggested mobile P2P file-sharing service.}, address = {Rome, Italy}, author = {Hoßfeld, Tobias and Tutschku, Kurt and Andersen, Frank-Uwe and de Meer, Hermann and Oberender, Jens}, booktitle = {Next Generation Internet Networks NGI2005}, keywords = {mobileptp}, month = {04}, title = {Simulative Performance Evaluation of a Mobile Peer-to-Peer File-Sharing System}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-164 %A Hoßfeld, Tobias %A Tutschku, Kurt %A Andersen, Frank-Uwe %A de Meer, Hermann %A Oberender, Jens %B Next Generation Internet Networks NGI2005 %C Rome, Italy %D 2005 %T Simulative Performance Evaluation of a Mobile Peer-to-Peer File-Sharing System %X Peer-to-Peer (P2P) file-sharing has become the killer application in the wired Internet and might also be highly attractive for mobile networks. In particular since UMTS operators are searching for new applications which do both: a) exploit the potential of the UMTS technology and b) motivate the user to adopt the new technology. In this work we are investigating the performance of an eDonkey-based mobile P2P file-sharing system by means of time-dynamic simulation. Mobile networks differ from wireline networks by the limited capacity of the radio link and the mobility of the users. P2P networks, in contrast, are overlays which consider the transport network in an abstract way. In a mobile environment, the question arises, whether the abstraction can be maintained and what will be the performance impact if there is any. We will show in detail how the mobile access technology (GPRS or UMTS), the churn behavior of mobile users, the file size of mobile specific content, and special infrastructure entities, such as a cache peer, influences the performance of the suggested mobile P2P file-sharing service.
• Sensitivity of Backup Capacity Requirements to Traffic Distribution and Resilience Constraints. Menth, Michael; Milbrandt, Jens; Reifert, Andreas. In 1st Conference on Next Generation Internet Networks (NGI 2005). Rome, Italy, 2005.
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  @inproceedings{info3-inproceedings-2005-165, address = {Rome, Italy}, author = {Menth, Michael and Milbrandt, Jens and Reifert, Andreas}, booktitle = {1st Conference on Next Generation Internet Networks (NGI 2005)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Sensitivity of Backup Capacity Requirements to Traffic Distribution and Resilience Constraints}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-165 %A Menth, Michael %A Milbrandt, Jens %A Reifert, Andreas %B 1st Conference on Next Generation Internet Networks (NGI 2005) %C Rome, Italy %D 2005 %T Sensitivity of Backup Capacity Requirements to Traffic Distribution and Resilience Constraints
• Comparison of Border-to-Border Budget Based Network Admission Control and Capacity Overprovisioning. Martin, Rüdiger; Menth, Michael; Charzinski, Joachim. In 4th International IFIP-TC6 Networking Conference, pp. 1056–1068. Waterloo, Canada, 2005.
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  @inproceedings{info3-inproceedings-2005-189, address = {Waterloo, Canada}, author = {Martin, Rüdiger and Menth, Michael and Charzinski, Joachim}, booktitle = {4th International IFIP-TC6 Networking Conference}, keywords = {sys:hidden:inproceedings}, month = {05}, pages = {1056-1068}, title = {Comparison of Border-to-Border Budget Based Network Admission Control and Capacity Overprovisioning}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-189 %A Martin, Rüdiger %A Menth, Michael %A Charzinski, Joachim %B 4th International IFIP-TC6 Networking Conference %C Waterloo, Canada %D 2005 %P 1056-1068 %T Comparison of Border-to-Border Budget Based Network Admission Control and Capacity Overprovisioning
• A filtered beam search approach to scheduling cluster tools in semiconductor manufacturing. Oechsner, Simon; Rose, Oliver. In Industrial Engineering Research Conference. Atlanta, GA, 2005.
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  @inproceedings{info3-inproceedings-2005-191, address = {Atlanta, GA}, author = {Oechsner, Simon and Rose, Oliver}, booktitle = {Industrial Engineering Research Conference}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {A filtered beam search approach to scheduling cluster tools in semiconductor manufacturing}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-191 %A Oechsner, Simon %A Rose, Oliver %B Industrial Engineering Research Conference %C Atlanta, GA %D 2005 %T A filtered beam search approach to scheduling cluster tools in semiconductor manufacturing
• Enabling Mobile Peer-to-Peer Networking. Oberender, Jens; Andersen, Frank-Uwe; de Meer, Hermann; Dedinski, Ivan; Hoßfeld, Tobias; Kappler, Cornelia; Mäder, Andreas; Tutschku, Kurt. In Mobile and Wireless Systems, LNCS 3427. Dagstuhl, Germany, 2005.
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  P2P file sharing systems account for a high percentage of the traffic volume in the fixed Internet, having exceeded http (WWW) or email traffic [1] [2]. The increasing availability of mobile data networks such as GPRS and UMTS in conjunction with attractive pricing schemes makes P2P file sharing an interesting application also in the mobile context. But the operation of P2P systems in mobile environments encounters several problems, such as a relatively narrow and expensive air interface, highly varying online states (presence) of the subscribers, a hierarchical network structure (GPRS), and limited device capabilities. P2P is a distributed application architecture where equal entities, denoted as peers, voluntarily share resources, e.g. files or CPU cycles, via direct, end-to-end exchanges. In order to share resources, P2P applications need to support two fundamental coordination and control functions: Resource mediation mechanisms, i.e. functions to locate resources or entities, and resource control mechanisms, i.e. functions to permit, prioritize, and schedule the access to resources. Pure P2P architectures are implementing both mechanisms in a fully decentralized manner [3], while Hybrid P2P systems utilize central entities that collect mediation data. An example for a Hybrid P2P system is the eDonkey filesharing protocol, where the index servers collect and distribute file location information about all peers. The desire of mobile network operators is to add value to the P2P data flows and to turn P2P into a service they can charge for. When creating such services operators retain control on traffic and content. However the basic P2P user experience and connectivity should be preserved. In this paper, we describe such a service and analyze its impact on the network usage by means of a simulation.

  @inproceedings{info3-inproceedings-2005-161, abstract = {P2P file sharing systems account for a high percentage of the traffic volume in the fixed Internet, having exceeded http (WWW) or email traffic [1] [2]. The increasing availability of mobile data networks such as GPRS and UMTS in conjunction with attractive pricing schemes makes P2P file sharing an interesting application also in the mobile context. But the operation of P2P systems in mobile environments encounters several problems, such as a relatively narrow and expensive air interface, highly varying online states (presence) of the subscribers, a hierarchical network structure (GPRS), and limited device capabilities. P2P is a distributed application architecture where equal entities, denoted as peers, voluntarily share resources, e.g. files or CPU cycles, via direct, end-to-end exchanges. In order to share resources, P2P applications need to support two fundamental coordination and control functions: Resource mediation mechanisms, i.e. functions to locate resources or entities, and resource control mechanisms, i.e. functions to permit, prioritize, and schedule the access to resources. Pure P2P architectures are implementing both mechanisms in a fully decentralized manner [3], while Hybrid P2P systems utilize central entities that collect mediation data. An example for a Hybrid P2P system is the eDonkey filesharing protocol, where the index servers collect and distribute file location information about all peers. The desire of mobile network operators is to add value to the P2P data flows and to turn P2P into a service they can charge for. When creating such services operators retain control on traffic and content. However the basic P2P user experience and connectivity should be preserved. In this paper, we describe such a service and analyze its impact on the network usage by means of a simulation.}, address = {Dagstuhl, Germany}, author = {Oberender, Jens and Andersen, Frank-Uwe and de Meer, Hermann and Dedinski, Ivan and Hoßfeld, Tobias and Kappler, Cornelia and Mäder, Andreas and Tutschku, Kurt}, booktitle = {Mobile and Wireless Systems, LNCS 3427}, keywords = {mobileptp}, month = {01}, title = {Enabling Mobile Peer-to-Peer Networking}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-161 %A Oberender, Jens %A Andersen, Frank-Uwe %A de Meer, Hermann %A Dedinski, Ivan %A Hoßfeld, Tobias %A Kappler, Cornelia %A Mäder, Andreas %A Tutschku, Kurt %B Mobile and Wireless Systems, LNCS 3427 %C Dagstuhl, Germany %D 2005 %T Enabling Mobile Peer-to-Peer Networking %X P2P file sharing systems account for a high percentage of the traffic volume in the fixed Internet, having exceeded http (WWW) or email traffic [1] [2]. The increasing availability of mobile data networks such as GPRS and UMTS in conjunction with attractive pricing schemes makes P2P file sharing an interesting application also in the mobile context. But the operation of P2P systems in mobile environments encounters several problems, such as a relatively narrow and expensive air interface, highly varying online states (presence) of the subscribers, a hierarchical network structure (GPRS), and limited device capabilities. P2P is a distributed application architecture where equal entities, denoted as peers, voluntarily share resources, e.g. files or CPU cycles, via direct, end-to-end exchanges. In order to share resources, P2P applications need to support two fundamental coordination and control functions: Resource mediation mechanisms, i.e. functions to locate resources or entities, and resource control mechanisms, i.e. functions to permit, prioritize, and schedule the access to resources. Pure P2P architectures are implementing both mechanisms in a fully decentralized manner [3], while Hybrid P2P systems utilize central entities that collect mediation data. An example for a Hybrid P2P system is the eDonkey filesharing protocol, where the index servers collect and distribute file location information about all peers. The desire of mobile network operators is to add value to the P2P data flows and to turn P2P into a service they can charge for. When creating such services operators retain control on traffic and content. However the basic P2P user experience and connectivity should be preserved. In this paper, we describe such a service and analyze its impact on the network usage by means of a simulation.
• An Analytic Method for Coverage Prediction in the UMTS Radio Network Planning Process. Staehle, Dirk. In IEEE VTC Spring. Stockholm, Sweden, 2005.
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  @inproceedings{info3-inproceedings-2005-187, address = {Stockholm, Sweden}, author = {Staehle, Dirk}, booktitle = {IEEE VTC Spring}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {An Analytic Method for Coverage Prediction in the UMTS Radio Network Planning Process}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-187 %A Staehle, Dirk %B IEEE VTC Spring %C Stockholm, Sweden %D 2005 %T An Analytic Method for Coverage Prediction in the UMTS Radio Network Planning Process
• On the Stochastic Scalability of Information Sharing Platforms. Tran-Gia, Phuoc; Binzenhöfer, Andreas. In 2005 Tyrrhenian International Workshop on Digital Communications. Sorrento, Italy, 2005.
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  @inproceedings{info3-inproceedings-2005-197, address = {Sorrento, Italy}, author = {Tran-Gia, Phuoc and Binzenhöfer, Andreas}, booktitle = {2005 Tyrrhenian International Workshop on Digital Communications}, keywords = {p2pinnop}, month = {07}, title = {On the Stochastic Scalability of Information Sharing Platforms}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-197 %A Tran-Gia, Phuoc %A Binzenhöfer, Andreas %B 2005 Tyrrhenian International Workshop on Digital Communications %C Sorrento, Italy %D 2005 %T On the Stochastic Scalability of Information Sharing Platforms
• Comparison of Crawling Strategies for an Optimized Mobile P2P Architecture. Hoßfeld, Tobias; Mäder, Andreas; Tutschku, Kurt; Tran-Gia, Phuoc; Andersen, Frank-Uwe; de Meer, Hermann; Dedinski, Ivan. In 19th International Teletraffic Congress (ITC19). Beijing, China, 2005.
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  Mobile networks differ from their wireline counterparts mainly by the high costs for air transmissions and by the mobility of the users. A new entity, denoted as the crawling peer, is suggested in order to optimize the resource mediation mechanism for a mobile P2P file sharing application. The crawling peer locates content on behalf of mobile peers. It is placed in the wireline part of the mobile network and thus, does not suffer from the above mentioned restrictions. The crawling peer is part of a comprehensive mobile P2P file sharing architecture [1] which is based on the popular eDonkey file sharing application. The performance of three querying strategies of the crawling peer is investigated with respect to banning at the index servers and the response time of requests, i.e. the time to find a file. The results show that the selection of an appropriate request strategy for the crawling peer maximizes the probability of locating a file while the probability to be banned by an eDonkey index server is minimized.

  @inproceedings{info3-inproceedings-2005-192, abstract = {Mobile networks differ from their wireline counterparts mainly by the high costs for air transmissions and by the mobility of the users. A new entity, denoted as the crawling peer, is suggested in order to optimize the resource mediation mechanism for a mobile P2P file sharing application. The crawling peer locates content on behalf of mobile peers. It is placed in the wireline part of the mobile network and thus, does not suffer from the above mentioned restrictions. The crawling peer is part of a comprehensive mobile P2P file sharing architecture [1] which is based on the popular eDonkey file sharing application. The performance of three querying strategies of the crawling peer is investigated with respect to banning at the index servers and the response time of requests, i.e. the time to find a file. The results show that the selection of an appropriate request strategy for the crawling peer maximizes the probability of locating a file while the probability to be banned by an eDonkey index server is minimized.}, address = {Beijing, China}, author = {Hoßfeld, Tobias and Mäder, Andreas and Tutschku, Kurt and Tran-Gia, Phuoc and Andersen, Frank-Uwe and de Meer, Hermann and Dedinski, Ivan}, booktitle = {19th International Teletraffic Congress (ITC19)}, keywords = {mobileptp}, month = {09}, title = {Comparison of Crawling Strategies for an Optimized Mobile P2P Architecture}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-192 %A Hoßfeld, Tobias %A Mäder, Andreas %A Tutschku, Kurt %A Tran-Gia, Phuoc %A Andersen, Frank-Uwe %A de Meer, Hermann %A Dedinski, Ivan %B 19th International Teletraffic Congress (ITC19) %C Beijing, China %D 2005 %T Comparison of Crawling Strategies for an Optimized Mobile P2P Architecture %X Mobile networks differ from their wireline counterparts mainly by the high costs for air transmissions and by the mobility of the users. A new entity, denoted as the crawling peer, is suggested in order to optimize the resource mediation mechanism for a mobile P2P file sharing application. The crawling peer locates content on behalf of mobile peers. It is placed in the wireline part of the mobile network and thus, does not suffer from the above mentioned restrictions. The crawling peer is part of a comprehensive mobile P2P file sharing architecture [1] which is based on the popular eDonkey file sharing application. The performance of three querying strategies of the crawling peer is investigated with respect to banning at the index servers and the response time of requests, i.e. the time to find a file. The results show that the selection of an appropriate request strategy for the crawling peer maximizes the probability of locating a file while the probability to be banned by an eDonkey index server is minimized.
• Comparison of Link-by-Link Admission Control and Capacity Overprovisioning. Martin, Rüdiger; Menth, Michael; Charzinski, Joachim. In 19th International Teletraffic Congress (ITC19). Beijing, China, 2005.
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  @inproceedings{info3-inproceedings-2005-190, address = {Beijing, China}, author = {Martin, Rüdiger and Menth, Michael and Charzinski, Joachim}, booktitle = {19th International Teletraffic Congress (ITC19)}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Comparison of Link-by-Link Admission Control and Capacity Overprovisioning}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-190 %A Martin, Rüdiger %A Menth, Michael %A Charzinski, Joachim %B 19th International Teletraffic Congress (ITC19) %C Beijing, China %D 2005 %T Comparison of Link-by-Link Admission Control and Capacity Overprovisioning
• Scheduling Cluster Tools Using Filtered Beam Search and Recipe Comparison. Oechsner, Simon; Rose, Oliver. In Winter Simulation Conference. Orlando, Florida, USA, 2005.
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  @inproceedings{info3-inproceedings-2005-202, address = {Orlando, Florida, USA}, author = {Oechsner, Simon and Rose, Oliver}, booktitle = {Winter Simulation Conference}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Scheduling Cluster Tools Using Filtered Beam Search and Recipe Comparison}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-202 %A Oechsner, Simon %A Rose, Oliver %B Winter Simulation Conference %C Orlando, Florida, USA %D 2005 %T Scheduling Cluster Tools Using Filtered Beam Search and Recipe Comparison
• On the Stability of Chord-based P2P Systems. Binzenhöfer, Andreas; Staehle, Dirk; Henjes, Robert. In GLOBECOM 2005, p. 5. St. Louis, MO, USA, 2005.
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  @inproceedings{info3-inproceedings-2005-198, address = {St. Louis, MO, USA}, author = {Binzenhöfer, Andreas and Staehle, Dirk and Henjes, Robert}, booktitle = {GLOBECOM 2005}, keywords = {p2pinnop}, month = 11, pages = 5, title = {On the Stability of Chord-based P2P Systems}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-198 %A Binzenhöfer, Andreas %A Staehle, Dirk %A Henjes, Robert %B GLOBECOM 2005 %C St. Louis, MO, USA %D 2005 %P 5 %T On the Stability of Chord-based P2P Systems
• Network Resilience through Multi-Topology Routing. Menth, Michael; Martin, Rüdiger. In The 5th International Workshop on Design of Reliable Communication Networks (DRCN). Ischia, Italy, 2005.
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  @inproceedings{info3-inproceedings-2005-203, address = {Ischia, Italy}, author = {Menth, Michael and Martin, Rüdiger}, booktitle = {The 5th International Workshop on Design of Reliable Communication Networks (DRCN)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Network Resilience through Multi-Topology Routing}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-203 %A Menth, Michael %A Martin, Rüdiger %B The 5th International Workshop on Design of Reliable Communication Networks (DRCN) %C Ischia, Italy %D 2005 %T Network Resilience through Multi-Topology Routing
• Analyzing and Modifying Chord’s Stabilization Algorithm to Handle High Churn Rates. Kunzmann, Gerald; Binzenhöfer, Andreas; Henjes, Robert. In MICC & ICON 2005. Kuala Lumpur, Malaysia, 2005.
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  @inproceedings{info3-inproceedings-2005-200, address = {Kuala Lumpur, Malaysia}, author = {Kunzmann, Gerald and Binzenhöfer, Andreas and Henjes, Robert}, booktitle = {MICC & ICON 2005}, keywords = {p2pinnop}, month = 11, title = {Analyzing and Modifying Chord's Stabilization Algorithm to Handle High Churn Rates}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-200 %A Kunzmann, Gerald %A Binzenhöfer, Andreas %A Henjes, Robert %B MICC & ICON 2005 %C Kuala Lumpur, Malaysia %D 2005 %T Analyzing and Modifying Chord's Stabilization Algorithm to Handle High Churn Rates
• Dimensioning of Hardware Components in UMTS Networks with Sectorized NodeBs. Mäder, Andreas; Staehle, Dirk; Schröder, Bernd. In 19th International Teletraffic Congress (ITC19). Bejing, China, 2005.
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  @inproceedings{info3-inproceedings-2005-196, address = {Bejing, China}, author = {Mäder, Andreas and Staehle, Dirk and Schröder, Bernd}, booktitle = {19th International Teletraffic Congress (ITC19)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Dimensioning of Hardware Components in UMTS Networks with Sectorized NodeBs}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-196 %A Mäder, Andreas %A Staehle, Dirk %A Schröder, Bernd %B 19th International Teletraffic Congress (ITC19) %C Bejing, China %D 2005 %T Dimensioning of Hardware Components in UMTS Networks with Sectorized NodeBs
• On the Code and Soft Capacity of the UMTS FDD Downlink and the Capacity Increase by using a Secondary Scrambling Code. Staehle, Dirk. In IEEE International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC). Berlin, Germany, 2005.
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  @inproceedings{info3-inproceedings-2005-201, address = {Berlin, Germany}, author = {Staehle, Dirk}, booktitle = {IEEE International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {On the Code and Soft Capacity of the UMTS FDD Downlink and the Capacity Increase by using a Secondary Scrambling Code}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-201 %A Staehle, Dirk %B IEEE International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC) %C Berlin, Germany %D 2005 %T On the Code and Soft Capacity of the UMTS FDD Downlink and the Capacity Increase by using a Secondary Scrambling Code
• The Network Utility Function: A Practicable Concept for Assessing Network Impact on Distributed Services. Radtke, Olaf; Fiedler, Markus; Binzenhöfer, Andreas; Chevul, Stefan; Tutschku, Kurt. In 19th International Teletraffic Congress (ITC19). Beijing, China, 2005.
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  @inproceedings{info3-inproceedings-2005-194, address = {Beijing, China}, author = {Radtke, Olaf and Fiedler, Markus and Binzenhöfer, Andreas and Chevul, Stefan and Tutschku, Kurt}, booktitle = {19th International Teletraffic Congress (ITC19)}, keywords = {automon}, month = {09}, title = {The Network Utility Function: A Practicable Concept for Assessing Network Impact on Distributed Services}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-194 %A Radtke, Olaf %A Fiedler, Markus %A Binzenhöfer, Andreas %A Chevul, Stefan %A Tutschku, Kurt %B 19th International Teletraffic Congress (ITC19) %C Beijing, China %D 2005 %T The Network Utility Function: A Practicable Concept for Assessing Network Impact on Distributed Services
• On the Fly Estimation of the Peer Population in a Chord-based P2P System. Binzenhöfer, Andreas; Staehle, Dirk; Henjes, Robert. In 19th International Teletraffic Congress (ITC19). Beijing, China, 2005.
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  @inproceedings{info3-inproceedings-2005-193, address = {Beijing, China}, author = {Binzenhöfer, Andreas and Staehle, Dirk and Henjes, Robert}, booktitle = {19th International Teletraffic Congress (ITC19)}, keywords = {p2pinnop}, month = {09}, title = {On the Fly Estimation of the Peer Population in a Chord-based P2P System}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-193 %A Binzenhöfer, Andreas %A Staehle, Dirk %A Henjes, Robert %B 19th International Teletraffic Congress (ITC19) %C Beijing, China %D 2005 %T On the Fly Estimation of the Peer Population in a Chord-based P2P System
• Adaptive Bandwidth Allocation: Impact of Traffic Demand Models for Wide Area Networks. Milbrandt, Jens; Menth, Michael; Kopf, Stefan. In 19th International Teletraffic Congress (ITC19). Beijing, China, 2005.
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  @inproceedings{info3-inproceedings-2005-188, address = {Beijing, China}, author = {Milbrandt, Jens and Menth, Michael and Kopf, Stefan}, booktitle = {19th International Teletraffic Congress (ITC19)}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Adaptive Bandwidth Allocation: Impact of Traffic Demand Models for Wide Area Networks}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-188 %A Milbrandt, Jens %A Menth, Michael %A Kopf, Stefan %B 19th International Teletraffic Congress (ITC19) %C Beijing, China %D 2005 %T Adaptive Bandwidth Allocation: Impact of Traffic Demand Models for Wide Area Networks
• Simulative Study of the WLAN Handover Performance. Pries, Rastin; Heck, Klaus. In OPNETWORK 2005. Washington D.C., USA, 2005.
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  @inproceedings{info3-inproceedings-2005-199, address = {Washington D.C., USA}, author = {Pries, Rastin and Heck, Klaus}, booktitle = {OPNETWORK 2005}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Simulative Study of the WLAN Handover Performance}, year = 2005 }

  %0 Conference Paper %1 info3-inproceedings-2005-199 %A Pries, Rastin %A Heck, Klaus %B OPNETWORK 2005 %C Washington D.C., USA %D 2005 %T Simulative Study of the WLAN Handover Performance

• Network Admission Control for Fault-Tolerant QoS Provisioning. Menth, Michael; Kopf, Stefan; Charzinski, Joachim. In 7th IEEE International Conference on High Speed Networks and Multimedia Communications (HSNMC’04). Toulouse, France, 2004.
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  @inproceedings{info3-inproceedings-2004-144, address = {Toulouse, France}, author = {Menth, Michael and Kopf, Stefan and Charzinski, Joachim}, booktitle = {7th IEEE International Conference on High Speed Networks and Multimedia Communications (HSNMC'04)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Network Admission Control for Fault-Tolerant QoS Provisioning}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-144 %A Menth, Michael %A Kopf, Stefan %A Charzinski, Joachim %B 7th IEEE International Conference on High Speed Networks and Multimedia Communications (HSNMC'04) %C Toulouse, France %D 2004 %T Network Admission Control for Fault-Tolerant QoS Provisioning
• A Performance Evaluation Framework for Network Admission Control Methods. Menth, Michael; Kopf, Stefan; Milbrandt, Jens. In IEEE Network Operations and Management Symposium (NOMS2004). Seoul, South Korea, 2004.
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  @inproceedings{info3-inproceedings-2004-139, address = {Seoul, South Korea}, author = {Menth, Michael and Kopf, Stefan and Milbrandt, Jens}, booktitle = {IEEE Network Operations and Management Symposium (NOMS2004)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {A Performance Evaluation Framework for Network Admission Control Methods}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-139 %A Menth, Michael %A Kopf, Stefan %A Milbrandt, Jens %B IEEE Network Operations and Management Symposium (NOMS2004) %C Seoul, South Korea %D 2004 %T A Performance Evaluation Framework for Network Admission Control Methods
• A Measurement-based Traffic Profile of the eDonkey Filesharing Service. Tutschku, Kurt. In 5th Passive and Active Measurement Workshop (PAM2004). Antibes Juan-les-Pins, France. April 19-20., 2004.
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  @inproceedings{info3-inproceedings-2004-137, address = {Antibes Juan-les-Pins, France. April 19-20.}, author = {Tutschku, Kurt}, booktitle = {5th Passive and Active Measurement Workshop (PAM2004)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {A Measurement-based Traffic Profile of the eDonkey Filesharing Service}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-137 %A Tutschku, Kurt %B 5th Passive and Active Measurement Workshop (PAM2004) %C Antibes Juan-les-Pins, France. April 19-20. %D 2004 %T A Measurement-based Traffic Profile of the eDonkey Filesharing Service
• Self-Protecting Multipaths - A Simple and Resource-Efficient Protection Switching Mechanism for MPLS Networks. Menth, Michael; Reifert, Andreas; Milbrandt, Jens. In The Third IFIP-TC6 Networking Conference (Networking2004). Athens, Greece, 2004.
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  @inproceedings{info3-inproceedings-2004-140, address = {Athens, Greece}, author = {Menth, Michael and Reifert, Andreas and Milbrandt, Jens}, booktitle = {The Third IFIP-TC6 Networking Conference (Networking2004)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Self-Protecting Multipaths - A Simple and Resource-Efficient Protection Switching Mechanism for MPLS Networks}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-140 %A Menth, Michael %A Reifert, Andreas %A Milbrandt, Jens %B The Third IFIP-TC6 Networking Conference (Networking2004) %C Athens, Greece %D 2004 %T Self-Protecting Multipaths - A Simple and Resource-Efficient Protection Switching Mechanism for MPLS Networks
• An Analytic Model for Deriving the Node-B Transmit Power in Heterogeneous UMTS Networks. Staehle, Dirk; Mäder, Andreas. In IEEE VTC Spring. Milano, Italy, 2004.
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  @inproceedings{info3-inproceedings-2004-136, address = {Milano, Italy}, author = {Staehle, Dirk and Mäder, Andreas}, booktitle = {IEEE VTC Spring}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {An Analytic Model for Deriving the Node-B Transmit Power in Heterogeneous UMTS Networks}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-136 %A Staehle, Dirk %A Mäder, Andreas %B IEEE VTC Spring %C Milano, Italy %D 2004 %T An Analytic Model for Deriving the Node-B Transmit Power in Heterogeneous UMTS Networks
• Simulative Study of the RTS/CTS Solution to the Hidden Node Problem in Infrastructure Wireless LANs. Heck, Klaus; Pries, Rastin; Wirth, Thomas. In 5th World Wireless Congress (WWC 04). San Francisco, 2004.
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  @inproceedings{info3-inproceedings-2004-138, address = {San Francisco}, author = {Heck, Klaus and Pries, Rastin and Wirth, Thomas}, booktitle = {5th World Wireless Congress (WWC 04)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Simulative Study of the RTS/CTS Solution to the Hidden Node Problem in Infrastructure Wireless LANs}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-138 %A Heck, Klaus %A Pries, Rastin %A Wirth, Thomas %B 5th World Wireless Congress (WWC 04) %C San Francisco %D 2004 %T Simulative Study of the RTS/CTS Solution to the Hidden Node Problem in Infrastructure Wireless LANs
• Impact of Routing and Traffic Distribution on the Performance of Network Admission Control. Menth, Michael; Milbrandt, Jens; Kopf, Stefan. In The Ninth IEEE Symposium on Computers and Communications (ISCC2004). Alexandria, Egypt, 2004.
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  @inproceedings{info3-inproceedings-2004-142, address = {Alexandria, Egypt}, author = {Menth, Michael and Milbrandt, Jens and Kopf, Stefan}, booktitle = {The Ninth IEEE Symposium on Computers and Communications (ISCC2004)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Impact of Routing and Traffic Distribution on the Performance of Network Admission Control}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-142 %A Menth, Michael %A Milbrandt, Jens %A Kopf, Stefan %B The Ninth IEEE Symposium on Computers and Communications (ISCC2004) %C Alexandria, Egypt %D 2004 %T Impact of Routing and Traffic Distribution on the Performance of Network Admission Control
• Experience Based Admission Control (EBAC). Menth, Michael; Milbrandt, Jens; Oechsner, Simon. In The Ninth IEEE Symposium on Computers and Communications (ISCC2004). Alexandria, Egypt, 2004.
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  @inproceedings{info3-inproceedings-2004-143, address = {Alexandria, Egypt}, author = {Menth, Michael and Milbrandt, Jens and Oechsner, Simon}, booktitle = {The Ninth IEEE Symposium on Computers and Communications (ISCC2004)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Experience Based Admission Control (EBAC)}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-143 %A Menth, Michael %A Milbrandt, Jens %A Oechsner, Simon %B The Ninth IEEE Symposium on Computers and Communications (ISCC2004) %C Alexandria, Egypt %D 2004 %T Experience Based Admission Control (EBAC)
• Capacity Assignment for NAC Budgets in Resilient Networks. Menth, Michael; Milbrandt, Jens; Kopf, Stefan. In 11th International Telecommunication Network Strategy and Planning Symposium (Networks2004). Vienna, Austria, 2004.
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  @inproceedings{info3-inproceedings-2004-141, address = {Vienna, Austria}, author = {Menth, Michael and Milbrandt, Jens and Kopf, Stefan}, booktitle = {11th International Telecommunication Network Strategy and Planning Symposium (Networks2004)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Capacity Assignment for NAC Budgets in Resilient Networks}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-141 %A Menth, Michael %A Milbrandt, Jens %A Kopf, Stefan %B 11th International Telecommunication Network Strategy and Planning Symposium (Networks2004) %C Vienna, Austria %D 2004 %T Capacity Assignment for NAC Budgets in Resilient Networks
• Uplink Blocking Probabilities in Heterogeneous WCDMA Networks considering Other-Cell Interference. Mäder, Andreas; Staehle, Dirk. In Southern African Telecommunication Networks & Applications Conference. South Western Cape, South Africa, 2004.
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  @inproceedings{info3-inproceedings-2004-153, address = {South Western Cape, South Africa}, author = {Mäder, Andreas and Staehle, Dirk}, booktitle = {Southern African Telecommunication Networks & Applications Conference}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Uplink Blocking Probabilities in Heterogeneous WCDMA Networks considering Other-Cell Interference}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-153 %A Mäder, Andreas %A Staehle, Dirk %B Southern African Telecommunication Networks & Applications Conference %C South Western Cape, South Africa %D 2004 %T Uplink Blocking Probabilities in Heterogeneous WCDMA Networks considering Other-Cell Interference
• Analytic Modelling of the WCDMA Downlink Capacity in Multi-Service Environments. Mäder, Andreas; Staehle, Dirk. In 16th ITC Specialist Seminar, pp. 229–238. Antwerp, Belgium, 2004.
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  @inproceedings{info3-inproceedings-2004-152, address = {Antwerp, Belgium}, author = {Mäder, Andreas and Staehle, Dirk}, booktitle = {16th ITC Specialist Seminar}, keywords = {sys:hidden:inproceedings}, month = {08}, pages = {229–238}, title = {Analytic Modelling of the WCDMA Downlink Capacity in Multi-Service Environments}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-152 %A Mäder, Andreas %A Staehle, Dirk %B 16th ITC Specialist Seminar %C Antwerp, Belgium %D 2004 %P 229--238 %T Analytic Modelling of the WCDMA Downlink Capacity in Multi-Service Environments
• Usage of Peer-to-Peer Technology in Ambient Intelligence. Kappler, Cornelia; Andersen, Frank-Uwe; Tutschku, Kurt. In VDE Kongress 2004 - ITG Fachtagung Ambient Intelligence. Berlin, 2004.
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  @inproceedings{info3-inproceedings-2004-148, address = {Berlin}, author = {Kappler, Cornelia and Andersen, Frank-Uwe and Tutschku, Kurt}, booktitle = {VDE Kongress 2004 - ITG Fachtagung Ambient Intelligence}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Usage of Peer-to-Peer Technology in Ambient Intelligence}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-148 %A Kappler, Cornelia %A Andersen, Frank-Uwe %A Tutschku, Kurt %B VDE Kongress 2004 - ITG Fachtagung Ambient Intelligence %C Berlin %D 2004 %T Usage of Peer-to-Peer Technology in Ambient Intelligence
• Information Diffusion in eDonkey Filesharing Networks. Hoßfeld, Tobias; Leibnitz, Kenji; Pries, Rastin; Tutschku, Kurt; Tran-Gia, Phuoc; Pawlikowski, Krzysztof. In ATNAC 2004, p. 8. Sydney, Australia, 2004.
  • [ Abstract ]
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  Peer-to-Peer (P2P) applications have become highly popular in today’s Internet due to the spread of file sharing platforms such as KaZaa, eDonkey, and BitTorrent. In this paper we investigate the diffusion behavior of a file shared by multiple sources in an eDonkey-like peer-to-peer (P2P) environment. We provide two simulation models, one which captures the chunk transfer in a detailed way and a simplified model, where the upload bandwidth is equally split among all chunks of the file. The simulation of a single chunk transmission is sufficient to obtain accurate results, which leads to a much shorter simulation time. We further investigate the non-stationary process of file diffusion in a statistically reliable way. Depending on the popularity of the file, we consider flash crowd arrivals and constant arrivals. We derive simple analytical expressions showing the relationship between the propagation of the file, i.e. the number of peers sharing the chunk, and the main influencing factors: e.g. sharing probability, access probability, or arrival rate.

  @inproceedings{info3-inproceedings-2004-150, abstract = {Peer-to-Peer (P2P) applications have become highly popular in today’s Internet due to the spread of file sharing platforms such as KaZaa, eDonkey, and BitTorrent. In this paper we investigate the diffusion behavior of a file shared by multiple sources in an eDonkey-like peer-to-peer (P2P) environment. We provide two simulation models, one which captures the chunk transfer in a detailed way and a simplified model, where the upload bandwidth is equally split among all chunks of the file. The simulation of a single chunk transmission is sufficient to obtain accurate results, which leads to a much shorter simulation time. We further investigate the non-stationary process of file diffusion in a statistically reliable way. Depending on the popularity of the file, we consider flash crowd arrivals and constant arrivals. We derive simple analytical expressions showing the relationship between the propagation of the file, i.e. the number of peers sharing the chunk, and the main influencing factors: e.g. sharing probability, access probability, or arrival rate.}, address = {Sydney, Australia}, author = {Hoßfeld, Tobias and Leibnitz, Kenji and Pries, Rastin and Tutschku, Kurt and Tran-Gia, Phuoc and Pawlikowski, Krzysztof}, booktitle = {ATNAC 2004}, keywords = {p2pfdai}, month = 12, pages = 8, title = {Information Diffusion in eDonkey Filesharing Networks}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-150 %A Hoßfeld, Tobias %A Leibnitz, Kenji %A Pries, Rastin %A Tutschku, Kurt %A Tran-Gia, Phuoc %A Pawlikowski, Krzysztof %B ATNAC 2004 %C Sydney, Australia %D 2004 %P 8 %T Information Diffusion in eDonkey Filesharing Networks %X Peer-to-Peer (P2P) applications have become highly popular in today’s Internet due to the spread of file sharing platforms such as KaZaa, eDonkey, and BitTorrent. In this paper we investigate the diffusion behavior of a file shared by multiple sources in an eDonkey-like peer-to-peer (P2P) environment. We provide two simulation models, one which captures the chunk transfer in a detailed way and a simplified model, where the upload bandwidth is equally split among all chunks of the file. The simulation of a single chunk transmission is sufficient to obtain accurate results, which leads to a much shorter simulation time. We further investigate the non-stationary process of file diffusion in a statistically reliable way. Depending on the popularity of the file, we consider flash crowd arrivals and constant arrivals. We derive simple analytical expressions showing the relationship between the propagation of the file, i.e. the number of peers sharing the chunk, and the main influencing factors: e.g. sharing probability, access probability, or arrival rate.
• Performance Comparison of Handover Mechanisms in Wireless LAN Networks. Pries, Rastin; Heck, Klaus. In ATNAC 2004, p. 4. Sydney, Australia, 2004.
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  @inproceedings{info3-inproceedings-2004-151, address = {Sydney, Australia}, author = {Pries, Rastin and Heck, Klaus}, booktitle = {ATNAC 2004}, keywords = {sys:hidden:inproceedings}, month = 12, pages = 4, title = {Performance Comparison of Handover Mechanisms in Wireless LAN Networks}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-151 %A Pries, Rastin %A Heck, Klaus %B ATNAC 2004 %C Sydney, Australia %D 2004 %P 4 %T Performance Comparison of Handover Mechanisms in Wireless LAN Networks
• Elastic Token Bucket - A Traffic Characterization for Time-Limited Bursty Traffic. Menth, Michael; Milbrandt, Jens; Zeiger, Florian. In 12th GI/ITG Conference on Measuring, Modelling and Evaluation of Computer and Communication Systems (MMB) together with 3rd Polish-German Teletraffic Symposium (PGTS). Dresden, Germany, 2004.
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  @inproceedings{info3-inproceedings-2004-146, address = {Dresden, Germany}, author = {Menth, Michael and Milbrandt, Jens and Zeiger, Florian}, booktitle = {12th GI/ITG Conference on Measuring, Modelling and Evaluation of Computer and Communication Systems (MMB) together with 3rd Polish-German Teletraffic Symposium (PGTS)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Elastic Token Bucket - A Traffic Characterization for Time-Limited Bursty Traffic}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-146 %A Menth, Michael %A Milbrandt, Jens %A Zeiger, Florian %B 12th GI/ITG Conference on Measuring, Modelling and Evaluation of Computer and Communication Systems (MMB) together with 3rd Polish-German Teletraffic Symposium (PGTS) %C Dresden, Germany %D 2004 %T Elastic Token Bucket - A Traffic Characterization for Time-Limited Bursty Traffic
• Delay Analysis of a Chord-based Peer-to-Peer File-Sharing System. Binzenhöfer, Andreas; Tran-Gia, Phuoc. In ATNAC 2004, p. 8. Sydney, Australia, 2004.
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  @inproceedings{info3-inproceedings-2004-154, address = {Sydney, Australia}, author = {Binzenhöfer, Andreas and Tran-Gia, Phuoc}, booktitle = {ATNAC 2004}, keywords = {p2pinnop}, month = 12, pages = 8, title = {Delay Analysis of a Chord-based Peer-to-Peer File-Sharing System}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-154 %A Binzenhöfer, Andreas %A Tran-Gia, Phuoc %B ATNAC 2004 %C Sydney, Australia %D 2004 %P 8 %T Delay Analysis of a Chord-based Peer-to-Peer File-Sharing System
• EBAC - A Simple Admission Control Mechanism. Milbrandt, Jens; Menth, Michael; Oechsner, Simon. In ICNP 2004, 12th IEEE International Conference on Network Protocols. Berlin, Germany, 2004.
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  @inproceedings{info3-inproceedings-2004-155, address = {Berlin, Germany}, author = {Milbrandt, Jens and Menth, Michael and Oechsner, Simon}, booktitle = {ICNP 2004, 12th IEEE International Conference on Network Protocols}, keywords = {sys:hidden:inproceedings}, month = 10, title = {EBAC - A Simple Admission Control Mechanism}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-155 %A Milbrandt, Jens %A Menth, Michael %A Oechsner, Simon %B ICNP 2004, 12th IEEE International Conference on Network Protocols %C Berlin, Germany %D 2004 %T EBAC - A Simple Admission Control Mechanism
• Improving the Timeliness of Rate Measurements. Martin, Rüdiger; Menth, Michael. In 12th GI/ITG Conference on Measuring, Modelling and Evaluation of Computer and Communication Systems (MMB) together with 3rd Polish-German Teletraffic Symposium (PGTS). Dresden, Germany, 2004.
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  @inproceedings{info3-inproceedings-2004-145, address = {Dresden, Germany}, author = {Martin, Rüdiger and Menth, Michael}, booktitle = {12th GI/ITG Conference on Measuring, Modelling and Evaluation of Computer and Communication Systems (MMB) together with 3rd Polish-German Teletraffic Symposium (PGTS)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Improving the Timeliness of Rate Measurements}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-145 %A Martin, Rüdiger %A Menth, Michael %B 12th GI/ITG Conference on Measuring, Modelling and Evaluation of Computer and Communication Systems (MMB) together with 3rd Polish-German Teletraffic Symposium (PGTS) %C Dresden, Germany %D 2004 %T Improving the Timeliness of Rate Measurements
• Performance of TCP/IP with MEDF Scheduling. Martin, Rüdiger; Menth, Michael; Phan-Gia, Vu. In Fifth International Workshop on Quality of Future Internet Services. Barcelona, Spain, 2004.
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  @inproceedings{info3-inproceedings-2004-149, address = {Barcelona, Spain}, author = {Martin, Rüdiger and Menth, Michael and Phan-Gia, Vu}, booktitle = {Fifth International Workshop on Quality of Future Internet Services}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Performance of TCP/IP with MEDF Scheduling}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-149 %A Martin, Rüdiger %A Menth, Michael %A Phan-Gia, Vu %B Fifth International Workshop on Quality of Future Internet Services %C Barcelona, Spain %D 2004 %T Performance of TCP/IP with MEDF Scheduling
• An Architecture Concept for Mobile P2P File Sharing Services. Andersen, Frank-Uwe; de Meer, Hermann; Dedinski, Ivan; Kappler, Cornelia; Mäder, Andreas; Oberender, Jens; Tutschku, Kurt. In Workshop at Informatik 2004 - Algorithms and Protocols for Efficient Peer-to-Peer Applications. Ulm, 2004.
  • [ Abstract ]
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  P2P file sharing is an interesting application in a mobile data network such as GSM/GPRS and UMTS. In particular in mobile environments, operation of P2P systems encounters several problems, such as a relatively narrow and expensive air interface, highly varying online-state (presence) of subscribers, hierarchical network structure, and limited device capabilities. The desire of operators is to add some value to P2P data flows and to turn them into services. At least some control over traffic and content should be possible, while preserving the basic P2P user experience and connectivity. Operation of P2P file sharing services in next generation mobile networks has to suit the needs of users as well as to accommodate the constraints imposed by 3G mobile technology and 3G network operation.

  @inproceedings{info3-inproceedings-2004-147, abstract = {P2P file sharing is an interesting application in a mobile data network such as GSM/GPRS and UMTS. In particular in mobile environments, operation of P2P systems encounters several problems, such as a relatively narrow and expensive air interface, highly varying online-state (presence) of subscribers, hierarchical network structure, and limited device capabilities. The desire of operators is to add some value to P2P data flows and to turn them into services. At least some control over traffic and content should be possible, while preserving the basic P2P user experience and connectivity. Operation of P2P file sharing services in next generation mobile networks has to suit the needs of users as well as to accommodate the constraints imposed by 3G mobile technology and 3G network operation.}, address = {Ulm}, author = {Andersen, Frank-Uwe and de Meer, Hermann and Dedinski, Ivan and Kappler, Cornelia and Mäder, Andreas and Oberender, Jens and Tutschku, Kurt}, booktitle = {Workshop at Informatik 2004 - Algorithms and Protocols for Efficient Peer-to-Peer Applications}, keywords = {mobileptp}, month = {09}, title = {An Architecture Concept for Mobile P2P File Sharing Services}, year = 2004 }

  %0 Conference Paper %1 info3-inproceedings-2004-147 %A Andersen, Frank-Uwe %A de Meer, Hermann %A Dedinski, Ivan %A Kappler, Cornelia %A Mäder, Andreas %A Oberender, Jens %A Tutschku, Kurt %B Workshop at Informatik 2004 - Algorithms and Protocols for Efficient Peer-to-Peer Applications %C Ulm %D 2004 %T An Architecture Concept for Mobile P2P File Sharing Services %X P2P file sharing is an interesting application in a mobile data network such as GSM/GPRS and UMTS. In particular in mobile environments, operation of P2P systems encounters several problems, such as a relatively narrow and expensive air interface, highly varying online-state (presence) of subscribers, hierarchical network structure, and limited device capabilities. The desire of operators is to add some value to P2P data flows and to turn them into services. At least some control over traffic and content should be possible, while preserving the basic P2P user experience and connectivity. Operation of P2P file sharing services in next generation mobile networks has to suit the needs of users as well as to accommodate the constraints imposed by 3G mobile technology and 3G network operation.

• An Analytic Approximation of the Uplink Capacity in a UMTS Network with Heterogeneous Traffic. Staehle, Dirk; Mäder, Andreas. In 18th International Teletraffic Congress (ITC18). Berlin, 2003.
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  @inproceedings{info3-inproceedings-2003-71, address = {Berlin}, author = {Staehle, Dirk and Mäder, Andreas}, booktitle = {18th International Teletraffic Congress (ITC18)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {An Analytic Approximation of the Uplink Capacity in a UMTS Network with Heterogeneous Traffic}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-71 %A Staehle, Dirk %A Mäder, Andreas %B 18th International Teletraffic Congress (ITC18) %C Berlin %D 2003 %T An Analytic Approximation of the Uplink Capacity in a UMTS Network with Heterogeneous Traffic
• A Measurement Study on Signaling on Gnutella Overlay Networks. de Meer, Hermann; Tutschku, Kurt. In Fachtagung - Kommunikation in Verteilten Systemen (KiVS) 2003. Leipzig, Germany, 2003.
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  @inproceedings{info3-inproceedings-2003-69, address = {Leipzig, Germany}, author = {de Meer, Hermann and Tutschku, Kurt}, booktitle = {Fachtagung - Kommunikation in Verteilten Systemen (KiVS) 2003}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {A Measurement Study on Signaling on Gnutella Overlay Networks}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-69 %A de Meer, Hermann %A Tutschku, Kurt %B Fachtagung - Kommunikation in Verteilten Systemen (KiVS) 2003 %C Leipzig, Germany %D 2003 %T A Measurement Study on Signaling on Gnutella Overlay Networks
• MEDF - A Simple Scheduling Algorithm for Two Real-Time Transport Service Classes with Application in the UTRAN. Schmid, Matthias; Menth, Michael; Heiß, Herbert; Reim, Thomas. In Infocom. San Francisco, 2003.
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  @inproceedings{info3-inproceedings-2003-76, address = {San Francisco}, author = {Schmid, Matthias and Menth, Michael and Heiß, Herbert and Reim, Thomas}, booktitle = {Infocom}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {MEDF - A Simple Scheduling Algorithm for Two Real-Time Transport Service Classes with Application in the UTRAN}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-76 %A Schmid, Matthias %A Menth, Michael %A Heiß, Herbert %A Reim, Thomas %B Infocom %C San Francisco %D 2003 %T MEDF - A Simple Scheduling Algorithm for Two Real-Time Transport Service Classes with Application in the UTRAN
• Analytic Approximation of the Effective Bandwidth for Best-Effort Services in UMTS Networks. Leibnitz, Kenji; Staehle, Dirk; Tran-Gia, Phuoc; Heck, Klaus; Schröder, Bernd; Weller, Albert. In Proc. of IEEE Vehicular Technology Conference (VTC-03 Spring). Jeju, South Korea, 2003.
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  @inproceedings{info3-inproceedings-2003-58, address = {Jeju, South Korea}, author = {Leibnitz, Kenji and Staehle, Dirk and Tran-Gia, Phuoc and Heck, Klaus and Schröder, Bernd and Weller, Albert}, booktitle = {Proc. of IEEE Vehicular Technology Conference (VTC-03 Spring)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Analytic Approximation of the Effective Bandwidth for Best-Effort Services in UMTS Networks}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-58 %A Leibnitz, Kenji %A Staehle, Dirk %A Tran-Gia, Phuoc %A Heck, Klaus %A Schröder, Bernd %A Weller, Albert %B Proc. of IEEE Vehicular Technology Conference (VTC-03 Spring) %C Jeju, South Korea %D 2003 %T Analytic Approximation of the Effective Bandwidth for Best-Effort Services in UMTS Networks
• Application of the Stochastic Fluid Flow model for Bottleneck Identification and Classification. Tutschku, Kurt; Fiedler, Markus. In Design, analysis and Simulation of Distributed Systems 2003 (DASD `03). 2003.
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  @inproceedings{info3-inproceedings-2003-68, author = {Tutschku, Kurt and Fiedler, Markus}, booktitle = {Design, analysis and Simulation of Distributed Systems 2003 (DASD `03)}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Application of the Stochastic Fluid Flow model for Bottleneck Identification and Classification}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-68 %A Tutschku, Kurt %A Fiedler, Markus %B Design, analysis and Simulation of Distributed Systems 2003 (DASD `03) %D 2003 %T Application of the Stochastic Fluid Flow model for Bottleneck Identification and Classification
• Web Traffic Performance in Wireless Lan Hot Spots. Heck, Klaus. In Fourth International Conference on 3G Mobile Communication Technologies (3G 2003). London, UK, 2003.
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  @inproceedings{info3-inproceedings-2003-55, address = {London, UK}, author = {Heck, Klaus}, booktitle = {Fourth International Conference on 3G Mobile Communication Technologies (3G 2003)}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Web Traffic Performance in Wireless Lan Hot Spots}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-55 %A Heck, Klaus %B Fourth International Conference on 3G Mobile Communication Technologies (3G 2003) %C London, UK %D 2003 %T Web Traffic Performance in Wireless Lan Hot Spots
• Macro Diversity Gain in UMTS Networks with Clustered User Distributions. Staehle, Dirk; Heck, Klaus; Leibnitz, Kenji. In International Teletraffic Congress (ITC-18). Berlin, Germany, 2003.
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  @inproceedings{info3-inproceedings-2003-57, address = {Berlin, Germany}, author = {Staehle, Dirk and Heck, Klaus and Leibnitz, Kenji}, booktitle = {International Teletraffic Congress (ITC-18)}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Macro Diversity Gain in UMTS Networks with Clustered User Distributions}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-57 %A Staehle, Dirk %A Heck, Klaus %A Leibnitz, Kenji %B International Teletraffic Congress (ITC-18) %C Berlin, Germany %D 2003 %T Macro Diversity Gain in UMTS Networks with Clustered User Distributions
• CSPF-Routed and Traffic-Driven Construction of LSP Hierarchies. Milbrandt, Jens; Menth, Michael; Reifert, Andreas. In Architectures for Quality of Service in the Internet (Art-QoS). Warsaw, 2003.
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  @inproceedings{info3-inproceedings-2003-56, address = {Warsaw}, author = {Milbrandt, Jens and Menth, Michael and Reifert, Andreas}, booktitle = {Architectures for Quality of Service in the Internet (Art-QoS)}, keywords = {sys:hidden:inproceedings}, month = {02}, title = {CSPF-Routed and Traffic-Driven Construction of LSP Hierarchies}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-56 %A Milbrandt, Jens %A Menth, Michael %A Reifert, Andreas %B Architectures for Quality of Service in the Internet (Art-QoS) %C Warsaw %D 2003 %T CSPF-Routed and Traffic-Driven Construction of LSP Hierarchies
• MPLS Traffic Engineering in OSPF Networks - A combined Approach. Köhler, Stefan; Binzenhöfer, Andreas. In 18th International Teletraffic Congress (ITC18). Berlin, 2003.
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  @inproceedings{info3-inproceedings-2003-74, address = {Berlin}, author = {Köhler, Stefan and Binzenhöfer, Andreas}, booktitle = {18th International Teletraffic Congress (ITC18)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {MPLS Traffic Engineering in OSPF Networks - A combined Approach}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-74 %A Köhler, Stefan %A Binzenhöfer, Andreas %B 18th International Teletraffic Congress (ITC18) %C Berlin %D 2003 %T MPLS Traffic Engineering in OSPF Networks - A combined Approach
• Fair Assignment of Efficient Network Admission Control Budgets. Menth, Michael; Gehrsitz, Sebastian; Milbrandt, Jens. In 18th International Teletraffic Congress, pp. 1121–1130. Berlin, Germany, 2003.
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  @inproceedings{info3-inproceedings-2003-77, address = {Berlin, Germany}, author = {Menth, Michael and Gehrsitz, Sebastian and Milbrandt, Jens}, booktitle = {18th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {1121 - 1130}, title = {Fair Assignment of Efficient Network Admission Control Budgets}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-77 %A Menth, Michael %A Gehrsitz, Sebastian %A Milbrandt, Jens %B 18th International Teletraffic Congress %C Berlin, Germany %D 2003 %P 1121 - 1130 %T Fair Assignment of Efficient Network Admission Control Budgets
• Wireless LAN Performance in Overlapping Cells. Heck, Klaus. In VTC Fall. Orlando, FL, 2003.
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  @inproceedings{info3-inproceedings-2003-73, address = {Orlando, FL}, author = {Heck, Klaus}, booktitle = {VTC Fall}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Wireless LAN Performance in Overlapping Cells}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-73 %A Heck, Klaus %B VTC Fall %C Orlando, FL %D 2003 %T Wireless LAN Performance in Overlapping Cells
• Introduction to Budget Based Network Admission Control Methods. Kopf, Stefan; Charzinski, Joachim; Menth, Michael; Milbrandt, Jens. In The 28th Annual IEEE Conference on Local Computer Networks (LCN2003). Bonn, Germany, 2003.
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  @inproceedings{info3-inproceedings-2003-78, address = {Bonn, Germany}, author = {Kopf, Stefan and Charzinski, Joachim and Menth, Michael and Milbrandt, Jens}, booktitle = {The 28th Annual IEEE Conference on Local Computer Networks (LCN2003)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Introduction to Budget Based Network Admission Control Methods}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-78 %A Kopf, Stefan %A Charzinski, Joachim %A Menth, Michael %A Milbrandt, Jens %B The 28th Annual IEEE Conference on Local Computer Networks (LCN2003) %C Bonn, Germany %D 2003 %T Introduction to Budget Based Network Admission Control Methods
• Impact of Network Topology on the Performance of Network Admission Control Methods. Charzinski, Joachim; Kopf, Stefan; Menth, Michael. In International Workshop on Multimedia Interactive Protocols and Systems (MIPS2003), pp. 195–206. Naples, Italy, 2003.
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  @inproceedings{info3-inproceedings-2003-79, address = {Naples, Italy}, author = {Charzinski, Joachim and Kopf, Stefan and Menth, Michael}, booktitle = {International Workshop on Multimedia Interactive Protocols and Systems (MIPS2003)}, keywords = {sys:hidden:inproceedings}, month = 11, pages = {195 – 206}, title = {Impact of Network Topology on the Performance of Network Admission Control Methods}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-79 %A Charzinski, Joachim %A Kopf, Stefan %A Menth, Michael %B International Workshop on Multimedia Interactive Protocols and Systems (MIPS2003) %C Naples, Italy %D 2003 %P 195 -- 206 %T Impact of Network Topology on the Performance of Network Admission Control Methods
• Auswirkungen der Virtualisierung auf Transparenz und Fehlerdiagnose in lokalen Netzen. Tutschku, Kurt; Binzenhöfer, Andreas. In 15. GI - Fachtagung der Fachgruppe BIK. Jülich, 2003.
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  @inproceedings{info3-inproceedings-2003-75, address = {Jülich}, author = {Tutschku, Kurt and Binzenhöfer, Andreas}, booktitle = {15. GI - Fachtagung der Fachgruppe BIK}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Auswirkungen der Virtualisierung auf Transparenz und Fehlerdiagnose in lokalen Netzen}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-75 %A Tutschku, Kurt %A Binzenhöfer, Andreas %B 15. GI - Fachtagung der Fachgruppe BIK %C Jülich %D 2003 %T Auswirkungen der Virtualisierung auf Transparenz und Fehlerdiagnose in lokalen Netzen
• Implementation of Adaptive Control for P2P Overlays. Koulouris, Theofrastos; Tutschku, Kurt; de Meer, Hermann; Henjes, Robert. In Proceedings Fifth Annual International Working Conference on Active Networks, Dec. 10-12 2003. Kyoto, Japan., 2003.
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  @inproceedings{info3-inproceedings-2003-135, address = {Kyoto, Japan.}, author = {Koulouris, Theofrastos and Tutschku, Kurt and de Meer, Hermann and Henjes, Robert}, booktitle = {Proceedings Fifth Annual International Working Conference on Active Networks, Dec. 10-12 2003,}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Implementation of Adaptive Control for P2P Overlays}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-135 %A Koulouris, Theofrastos %A Tutschku, Kurt %A de Meer, Hermann %A Henjes, Robert %B Proceedings Fifth Annual International Working Conference on Active Networks, Dec. 10-12 2003, %C Kyoto, Japan. %D 2003 %T Implementation of Adaptive Control for P2P Overlays
• Identification of Performance Degradation in IP Networks Using Throughput Statistics. Fiedler, Markus; Tutschku, Kurt; Carlsson, Patrik. In the 18th International Teletraffic Congress - ITC18. Berlin, Germany, 2003.
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  @inproceedings{info3-inproceedings-2003-70, address = {Berlin, Germany}, author = {Fiedler, Markus and Tutschku, Kurt and Carlsson, Patrik}, booktitle = {the 18th International Teletraffic Congress - ITC18}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Identification of Performance Degradation in IP Networks Using Throughput Statistics}, year = 2003 }

  %0 Conference Paper %1 info3-inproceedings-2003-70 %A Fiedler, Markus %A Tutschku, Kurt %A Carlsson, Patrik %B the 18th International Teletraffic Congress - ITC18 %C Berlin, Germany %D 2003 %T Identification of Performance Degradation in IP Networks Using Throughput Statistics

• Obtaining Reliable Bit Rate Measurements in SNMP-Managed Networks. Fiedler, Markus; Tutschku, Kurt; Carlsson, Patrik. In of the 15th ITC Specialist Seminar- Internet Traffic Engineering and Traffic Management. Würzburg, Germany, 2002.
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  @inproceedings{info3-inproceedings-2002-64, address = {Würzburg, Germany}, author = {Fiedler, Markus and Tutschku, Kurt and Carlsson, Patrik}, booktitle = {of the 15th ITC Specialist Seminar- Internet Traffic Engineering and Traffic Management}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Obtaining Reliable Bit Rate Measurements in SNMP-Managed Networks}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-64 %A Fiedler, Markus %A Tutschku, Kurt %A Carlsson, Patrik %B of the 15th ITC Specialist Seminar- Internet Traffic Engineering and Traffic Management %C Würzburg, Germany %D 2002 %T Obtaining Reliable Bit Rate Measurements in SNMP-Managed Networks
• A Graph-Theoretical Notation for the Construction of LSP Hierarchies. Menth, Michael; Hauck, Norbert. In 15th International Teletraffic Congress Specialists Seminar, pp. 13–23. Würzburg, Germany, 2002.
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  @inproceedings{info3-inproceedings-2002-53, address = {Würzburg, Germany}, author = {Menth, Michael and Hauck, Norbert}, booktitle = {15th International Teletraffic Congress Specialists Seminar}, keywords = {sys:hidden:inproceedings}, pages = {13 - 23}, title = {A Graph-Theoretical Notation for the Construction of LSP Hierarchies}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-53 %A Menth, Michael %A Hauck, Norbert %B 15th International Teletraffic Congress Specialists Seminar %C Würzburg, Germany %D 2002 %P 13 - 23 %T A Graph-Theoretical Notation for the Construction of LSP Hierarchies
• Performance Evaluation of the Extensions for Control Message Retransmissions in RSVP. Menth, Michael; Martin, Rüdiger. In 7th International Workshop on Protocols For High-Speed Networks (PfHSN 2002), pp. 35–49. Berlin, Germany, 2002.
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  @inproceedings{info3-inproceedings-2002-51, address = {Berlin, Germany}, author = {Menth, Michael and Martin, Rüdiger}, booktitle = {7th International Workshop on Protocols For High-Speed Networks (PfHSN 2002)}, keywords = {sys:hidden:inproceedings}, pages = {35 - 49}, title = {Performance Evaluation of the Extensions for Control Message Retransmissions in RSVP}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-51 %A Menth, Michael %A Martin, Rüdiger %B 7th International Workshop on Protocols For High-Speed Networks (PfHSN 2002) %C Berlin, Germany %D 2002 %P 35 - 49 %T Performance Evaluation of the Extensions for Control Message Retransmissions in RSVP
• A Perfomance Management Architecture for Peer-to-Peer Services Based on Application-level Active Networks. de Meer, Hermann; Tutschku, Kurt. In the Network Operation and management Symposium 2002 - NOMS 2002. Florence, Italy, 2002.
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  @inproceedings{info3-inproceedings-2002-63, address = {Florence, Italy}, author = {de Meer, Hermann and Tutschku, Kurt}, booktitle = {the Network Operation and management Symposium 2002 - NOMS 2002}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {A Perfomance Management Architecture for Peer-to-Peer Services Based on Application-level Active Networks}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-63 %A de Meer, Hermann %A Tutschku, Kurt %B the Network Operation and management Symposium 2002 - NOMS 2002 %C Florence, Italy %D 2002 %T A Perfomance Management Architecture for Peer-to-Peer Services Based on Application-level Active Networks
• Approximating the Othercell Interference Distribution in Inhomogeneous UMTS Networks. Weller, Albert; Heck, Klaus; Schröder, Bernd; Staehle, Dirk; Tran-Gia, Phuoc; Leibnitz, Kenji. In Proc. of the IEEE Vehicular Technology Conference (VTC-02 Spring). Birmingham, AL, 2002.
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  @inproceedings{info3-inproceedings-2002-43, address = {Birmingham, AL}, author = {Weller, Albert and Heck, Klaus and Schröder, Bernd and Staehle, Dirk and Tran-Gia, Phuoc and Leibnitz, Kenji}, booktitle = {Proc. of the IEEE Vehicular Technology Conference (VTC-02 Spring)}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Approximating the Othercell Interference Distribution in Inhomogeneous UMTS Networks}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-43 %A Weller, Albert %A Heck, Klaus %A Schröder, Bernd %A Staehle, Dirk %A Tran-Gia, Phuoc %A Leibnitz, Kenji %B Proc. of the IEEE Vehicular Technology Conference (VTC-02 Spring) %C Birmingham, AL %D 2002 %T Approximating the Othercell Interference Distribution in Inhomogeneous UMTS Networks
• Performance Tradeoffs for Header Compression in MPLS Networks. Rose, Oliver; Menth, Michael. In 10th International Telecommunication Network Planning Symposium (Networks 2002), pp. 503–508. Munich, Germany, 2002.
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  @inproceedings{info3-inproceedings-2002-52, address = {Munich, Germany}, author = {Rose, Oliver and Menth, Michael}, booktitle = {10th International Telecommunication Network Planning Symposium (Networks 2002)}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = {503 - 508}, title = {Performance Tradeoffs for Header Compression in MPLS Networks}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-52 %A Rose, Oliver %A Menth, Michael %B 10th International Telecommunication Network Planning Symposium (Networks 2002) %C Munich, Germany %D 2002 %P 503 - 508 %T Performance Tradeoffs for Header Compression in MPLS Networks
• Effects of Soft Handover on the UMTS Downlink Performance. Staehle, Dirk; Leibnitz, Kenji; Heck, Klaus. In Proc. of IEEE Vehicular Technology Conference (VTC-02 Fall). Vancouver, Canada, 2002.
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  @inproceedings{info3-inproceedings-2002-44, address = {Vancouver, Canada}, author = {Staehle, Dirk and Leibnitz, Kenji and Heck, Klaus}, booktitle = {Proc. of IEEE Vehicular Technology Conference (VTC-02 Fall)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Effects of Soft Handover on the UMTS Downlink Performance}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-44 %A Staehle, Dirk %A Leibnitz, Kenji %A Heck, Klaus %B Proc. of IEEE Vehicular Technology Conference (VTC-02 Fall) %C Vancouver, Canada %D 2002 %T Effects of Soft Handover on the UMTS Downlink Performance
• Routing-based IP Network Optimisation. Staehle, Dirk; Köhler, Stefan; Kohlhaas, Ute. In 15th International Teletraffic Congress Specialists Seminar. Würzburg, 2002.
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  @inproceedings{info3-inproceedings-2002-72, address = {Würzburg}, author = {Staehle, Dirk and Köhler, Stefan and Kohlhaas, Ute}, booktitle = {15th International Teletraffic Congress Specialists Seminar}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Routing-based IP Network Optimisation}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-72 %A Staehle, Dirk %A Köhler, Stefan %A Kohlhaas, Ute %B 15th International Teletraffic Congress Specialists Seminar %C Würzburg %D 2002 %T Routing-based IP Network Optimisation
• Diversity Effects on the Soft Handover Gain in UMTS networks. Staehle, Dirk; Leibnitz, Kenji; Heck, Klaus. In Proc. of IEEE Vehicular Technology Conference (VTC-02 Fall). Vancouver, Canada, 2002.
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  @inproceedings{info3-inproceedings-2002-45, address = {Vancouver, Canada}, author = {Staehle, Dirk and Leibnitz, Kenji and Heck, Klaus}, booktitle = {Proc. of IEEE Vehicular Technology Conference (VTC-02 Fall)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Diversity Effects on the Soft Handover Gain in UMTS networks}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-45 %A Staehle, Dirk %A Leibnitz, Kenji %A Heck, Klaus %B Proc. of IEEE Vehicular Technology Conference (VTC-02 Fall) %C Vancouver, Canada %D 2002 %T Diversity Effects on the Soft Handover Gain in UMTS networks
• Application of the Stochastic fluid Flow model for Bottleneck Identification and Classification. Fiedler, Markus; Tutschku, Kurt. In 5th MC Meeting of Cost Project 279, p. COST 279TD(02)046. Lyngby, Denmark, 2002.
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  @inproceedings{info3-inproceedings-2002-65, address = {Lyngby, Denmark}, author = {Fiedler, Markus and Tutschku, Kurt}, booktitle = {5th MC Meeting of Cost Project 279}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {COST 279TD(02)046}, title = {Application of the Stochastic fluid Flow model for Bottleneck Identification and Classification}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-65 %A Fiedler, Markus %A Tutschku, Kurt %B 5th MC Meeting of Cost Project 279 %C Lyngby, Denmark %D 2002 %P COST 279TD(02)046 %T Application of the Stochastic fluid Flow model for Bottleneck Identification and Classification
• A Measurement-based Investigation on Signaling in Gnutella Overlay Networks - Providing Insights to Third Generation InternetApplications?. Tutschku, Kurt; de Meer, Hermann. In the 1th Workshop Design and Performance Evaluation of 3G Internet Technologies collocated woth MASCOTS 2002. Fort Worth, 2002.
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  @inproceedings{info3-inproceedings-2002-66, address = {Fort Worth}, author = {Tutschku, Kurt and de Meer, Hermann}, booktitle = {the 1th Workshop Design and Performance Evaluation of 3G Internet Technologies collocated woth MASCOTS 2002}, keywords = {sys:hidden:inproceedings}, month = 10, title = {A Measurement-based Investigation on Signaling in Gnutella Overlay Networks - Providing Insights to Third Generation InternetApplications?}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-66 %A Tutschku, Kurt %A de Meer, Hermann %B the 1th Workshop Design and Performance Evaluation of 3G Internet Technologies collocated woth MASCOTS 2002 %C Fort Worth %D 2002 %T A Measurement-based Investigation on Signaling in Gnutella Overlay Networks - Providing Insights to Third Generation InternetApplications?
• Fast Prediction of the Coverage Area in UMTS Networks. Leibnitz, Kenji; Heck, Klaus; Staehle, Dirk. In Proc. of IEEE GLOBECOM. Taipei, Taiwan, 2002.
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  @inproceedings{info3-inproceedings-2002-46, address = {Taipei, Taiwan}, author = {Leibnitz, Kenji and Heck, Klaus and Staehle, Dirk}, booktitle = {Proc. of IEEE GLOBECOM}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Fast Prediction of the Coverage Area in UMTS Networks}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-46 %A Leibnitz, Kenji %A Heck, Klaus %A Staehle, Dirk %B Proc. of IEEE GLOBECOM %C Taipei, Taiwan %D 2002 %T Fast Prediction of the Coverage Area in UMTS Networks
• Dynamic Operation of Peer-to-Peer Overlays. Tutschku, Kurt; de Meer, Hermann. In Fourth Annual Internation Working Conference on Active Networks. ETH Zürich, Switzerland, 2002.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2002-67, address = {ETH Zürich, Switzerland}, author = {Tutschku, Kurt and de Meer, Hermann}, booktitle = {Fourth Annual Internation Working Conference on Active Networks}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Dynamic Operation of Peer-to-Peer Overlays}, year = 2002 }

  %0 Conference Paper %1 info3-inproceedings-2002-67 %A Tutschku, Kurt %A de Meer, Hermann %B Fourth Annual Internation Working Conference on Active Networks %C ETH Zürich, Switzerland %D 2002 %T Dynamic Operation of Peer-to-Peer Overlays

• A Scalable Scheduling Mechanism with Specific Application to AAL2/ATM Multiplexing. Menth, Michael; Schneeberger, Stefan. In 14th International Teletraffic Congress Specialists Seminar, pp. 277–286. Girona, Spain, 2001.
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  @inproceedings{info3-inproceedings-2001-48, address = {Girona, Spain}, author = {Menth, Michael and Schneeberger, Stefan}, booktitle = {14th International Teletraffic Congress Specialists Seminar}, keywords = {sys:hidden:inproceedings}, pages = {277 - 286}, title = {A Scalable Scheduling Mechanism with Specific Application to AAL2/ATM Multiplexing}, year = 2001 }

  %0 Conference Paper %1 info3-inproceedings-2001-48 %A Menth, Michael %A Schneeberger, Stefan %B 14th International Teletraffic Congress Specialists Seminar %C Girona, Spain %D 2001 %P 277 - 286 %T A Scalable Scheduling Mechanism with Specific Application to AAL2/ATM Multiplexing
• Analytic Performance Evaluation of the RED Algorithm for QoS in TCP/IP Networks. Vicari, Norbert; Köhler, Stefan; Menth, Michael. In 9th IFIP Working Conference on Performance Modelling and Evaluation of ATM & IP Networks, pp. 178–190. Budapest, Hungary, 2001.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2001-49, address = {Budapest, Hungary}, author = {Vicari, Norbert and Köhler, Stefan and Menth, Michael}, booktitle = {9th IFIP Working Conference on Performance Modelling and Evaluation of ATM & IP Networks}, keywords = {sys:hidden:inproceedings}, pages = {178 - 190}, title = {Analytic Performance Evaluation of the RED Algorithm for QoS in TCP/IP Networks}, year = 2001 }

  %0 Conference Paper %1 info3-inproceedings-2001-49 %A Vicari, Norbert %A Köhler, Stefan %A Menth, Michael %B 9th IFIP Working Conference on Performance Modelling and Evaluation of ATM & IP Networks %C Budapest, Hungary %D 2001 %P 178 - 190 %T Analytic Performance Evaluation of the RED Algorithm for QoS in TCP/IP Networks
• A Scalable Protocol Architecture for End-to-End Signaling and Resource Reservation in IP Networks. Menth, Michael. In 17th International Teletraffic Congress, pp. 211–222. Salvador de Bahia, Brazil, 2001.
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  @inproceedings{info3-inproceedings-2001-50, address = {Salvador de Bahia, Brazil}, author = {Menth, Michael}, booktitle = {17th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, pages = {211 - 222}, title = {A Scalable Protocol Architecture for End-to-End Signaling and Resource Reservation in IP Networks}, year = 2001 }

  %0 Conference Paper %1 info3-inproceedings-2001-50 %A Menth, Michael %B 17th International Teletraffic Congress %C Salvador de Bahia, Brazil %D 2001 %P 211 - 222 %T A Scalable Protocol Architecture for End-to-End Signaling and Resource Reservation in IP Networks
• MPEG-L/MRP: Implementing Adaptive Streaming of MPEG Videos for Interactive Internet Applications. Boll, Susanne; Menth, Michael; Heinlein, Christian; Klas, Wolfgang. In ACM Multimedia 2001. Ottawa/Ontario, Canada, 2001.
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  @inproceedings{info3-inproceedings-2001-54, address = {Ottawa/Ontario, Canada}, author = {Boll, Susanne and Menth, Michael and Heinlein, Christian and Klas, Wolfgang}, booktitle = {ACM Multimedia 2001}, keywords = {sys:hidden:inproceedings}, title = {MPEG-L/MRP: Implementing Adaptive Streaming of MPEG Videos for Interactive Internet Applications}, year = 2001 }

  %0 Conference Paper %1 info3-inproceedings-2001-54 %A Boll, Susanne %A Menth, Michael %A Heinlein, Christian %A Klas, Wolfgang %B ACM Multimedia 2001 %C Ottawa/Ontario, Canada %D 2001 %T MPEG-L/MRP: Implementing Adaptive Streaming of MPEG Videos for Interactive Internet Applications
• Characterizing Network Performance for Enterprise Networks. Tutschku, Kurt; Baier, Herbert. In the PAM2001 - Passive and Active Measurements Workshop 2001. Amsterdam, 2001.
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  @inproceedings{info3-inproceedings-2001-62, address = {Amsterdam}, author = {Tutschku, Kurt and Baier, Herbert}, booktitle = {the PAM2001 - Passive and Active Measurements Workshop 2001}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Characterizing Network Performance for Enterprise Networks}, year = 2001 }

  %0 Conference Paper %1 info3-inproceedings-2001-62 %A Tutschku, Kurt %A Baier, Herbert %B the PAM2001 - Passive and Active Measurements Workshop 2001 %C Amsterdam %D 2001 %T Characterizing Network Performance for Enterprise Networks
• Analytical Characterization of the Soft Handover Gain in UMTS. Tran-Gia, Phuoc; Staehle, Dirk; Heck, Klaus; Schröder, Bernd; Leibnitz, Kenji; Weller, Albert. In Proc. of the IEEE Vehicular Technology Conference (VTC-01 Fall). Atlantic City, NJ, 2001.
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  @inproceedings{info3-inproceedings-2001-41, address = {Atlantic City, NJ}, author = {Tran-Gia, Phuoc and Staehle, Dirk and Heck, Klaus and Schröder, Bernd and Leibnitz, Kenji and Weller, Albert}, booktitle = {Proc. of the IEEE Vehicular Technology Conference (VTC-01 Fall)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Analytical Characterization of the Soft Handover Gain in UMTS}, year = 2001 }

  %0 Conference Paper %1 info3-inproceedings-2001-41 %A Tran-Gia, Phuoc %A Staehle, Dirk %A Heck, Klaus %A Schröder, Bernd %A Leibnitz, Kenji %A Weller, Albert %B Proc. of the IEEE Vehicular Technology Conference (VTC-01 Fall) %C Atlantic City, NJ %D 2001 %T Analytical Characterization of the Soft Handover Gain in UMTS
• An analytical approach for determining coverage probabilities in large UMTS networks. Tran-Gia, Phuoc; Leibnitz, Kenji; Staehle, Dirk; Schröder, Bernd; Liesenfeld, Bernhard; Weller, Albert. In Proc. of the IEEE Vehicular Technology Conference (VTC-01 Fall). Atlantic City, NJ, 2001.
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  @inproceedings{info3-inproceedings-2001-42, address = {Atlantic City, NJ}, author = {Tran-Gia, Phuoc and Leibnitz, Kenji and Staehle, Dirk and Schröder, Bernd and Liesenfeld, Bernhard and Weller, Albert}, booktitle = {Proc. of the IEEE Vehicular Technology Conference (VTC-01 Fall)}, keywords = {sys:hidden:inproceedings}, month = 10, title = {An analytical approach for determining coverage probabilities in large UMTS networks}, year = 2001 }

  %0 Conference Paper %1 info3-inproceedings-2001-42 %A Tran-Gia, Phuoc %A Leibnitz, Kenji %A Staehle, Dirk %A Schröder, Bernd %A Liesenfeld, Bernhard %A Weller, Albert %B Proc. of the IEEE Vehicular Technology Conference (VTC-01 Fall) %C Atlantic City, NJ %D 2001 %T An analytical approach for determining coverage probabilities in large UMTS networks
• Performance Evaluation of Interference and Cell Loading in a UMTS Network. Krauß, Armin; Leibnitz, Kenji. In Proc. of the 17th International Teletraffic Congress (ITC-17). Salvador de Bahia, Brazil, 2001.
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  @inproceedings{info3-inproceedings-2001-40, address = {Salvador de Bahia, Brazil}, author = {Krauß, Armin and Leibnitz, Kenji}, booktitle = {Proc. of the 17th International Teletraffic Congress (ITC-17)}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Performance Evaluation of Interference and Cell Loading in a UMTS Network}, year = 2001 }

  %0 Conference Paper %1 info3-inproceedings-2001-40 %A Krauß, Armin %A Leibnitz, Kenji %B Proc. of the 17th International Teletraffic Congress (ITC-17) %C Salvador de Bahia, Brazil %D 2001 %T Performance Evaluation of Interference and Cell Loading in a UMTS Network
• QoS of Internet Access with GPRS. Tsipotis, Konstantin; Leibnitz, Kenji; Staehle, Dirk. In ACM International Workshop on Modeling Analysis and Simulation of Wireless and Mobile systems (MSWiM 2001). Rome, 2001.
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  @inproceedings{info3-inproceedings-2001-39, address = {Rome}, author = {Tsipotis, Konstantin and Leibnitz, Kenji and Staehle, Dirk}, booktitle = {ACM International Workshop on Modeling Analysis and Simulation of Wireless and Mobile systems (MSWiM 2001)}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {QoS of Internet Access with GPRS}, year = 2001 }

  %0 Conference Paper %1 info3-inproceedings-2001-39 %A Tsipotis, Konstantin %A Leibnitz, Kenji %A Staehle, Dirk %B ACM International Workshop on Modeling Analysis and Simulation of Wireless and Mobile systems (MSWiM 2001) %C Rome %D 2001 %T QoS of Internet Access with GPRS

• Neural combustion control. Müller, Rainer. In International Conference on Artificial Neural Networks ICANN. 1101-1106, 2000.
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  @inproceedings{info3-inproceedings-2000-33, address = {1101-1106}, author = {Müller, Rainer}, booktitle = {International Conference on Artificial Neural Networks ICANN}, keywords = {sys:hidden:inproceedings}, title = {Neural combustion control}, year = 2000 }

  %0 Conference Paper %1 info3-inproceedings-2000-33 %A Müller, Rainer %B International Conference on Artificial Neural Networks ICANN %C 1101-1106 %D 2000 %T Neural combustion control
• Nonlinear, statistical data-analysis for the optimal construction of neural-network inputs with the concept of a mutual information. Heister, Frank; Schock, Gregor. In European Symposium on Artificial Neural Networks Proceedings. 2000.
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  @inproceedings{info3-inproceedings-2000-3, author = {Heister, Frank and Schock, Gregor}, booktitle = {European Symposium on Artificial Neural Networks Proceedings}, keywords = {sys:hidden:inproceedings}, title = {Nonlinear, statistical data-analysis for the optimal construction of neural-network inputs with the concept of a mutual information}, year = 2000 }

  %0 Conference Paper %1 info3-inproceedings-2000-3 %A Heister, Frank %A Schock, Gregor %B European Symposium on Artificial Neural Networks Proceedings %D 2000 %T Nonlinear, statistical data-analysis for the optimal construction of neural-network inputs with the concept of a mutual information
• Analysis of the short term impact of changes in product mix. Dümmler, Matthias; Rose, Oliver. In International Conference on Modeling and Analysis of Semiconductor Manufacturing (MASM 2000), pp. 133–138. 2000.
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  @inproceedings{info3-inproceedings-2000-4, author = {Dümmler, Matthias and Rose, Oliver}, booktitle = {International Conference on Modeling and Analysis of Semiconductor Manufacturing (MASM 2000)}, keywords = {sys:hidden:inproceedings}, pages = {133-138}, title = {Analysis of the short term impact of changes in product mix}, year = 2000 }

  %0 Conference Paper %1 info3-inproceedings-2000-4 %A Dümmler, Matthias %A Rose, Oliver %B International Conference on Modeling and Analysis of Semiconductor Manufacturing (MASM 2000) %D 2000 %P 133-138 %T Analysis of the short term impact of changes in product mix
• The Performance of Multiplexing Voice and Circuit Switched Data in UMTS over IP Networks. Menth, Michael. In Protocols for Multimedia Systems (PROMS2000), pp. 312–321. Cracow, Poland, 2000.
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  @inproceedings{info3-inproceedings-2000-47, address = {Cracow, Poland}, author = {Menth, Michael}, booktitle = {Protocols for Multimedia Systems (PROMS2000)}, keywords = {sys:hidden:inproceedings}, pages = {312 - 321}, title = {The Performance of Multiplexing Voice and Circuit Switched Data in UMTS over IP Networks}, year = 2000 }

  %0 Conference Paper %1 info3-inproceedings-2000-47 %A Menth, Michael %B Protocols for Multimedia Systems (PROMS2000) %C Cracow, Poland %D 2000 %P 312 - 321 %T The Performance of Multiplexing Voice and Circuit Switched Data in UMTS over IP Networks
• Carrying wireless traffic in UMTS over IP using realtime transfer protocol multiplexing. Menth, Michael. In 12th ITC Specialist Seminar, pp. 13–25. Lillehammer, Norway, 2000.
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  @inproceedings{info3-inproceedings-2000-2, address = {Lillehammer, Norway}, author = {Menth, Michael}, booktitle = {12th ITC Specialist Seminar}, keywords = {sys:hidden:inproceedings}, month = {03}, pages = {13 - 25}, title = {Carrying wireless traffic in UMTS over IP using realtime transfer protocol multiplexing}, year = 2000 }

  %0 Conference Paper %1 info3-inproceedings-2000-2 %A Menth, Michael %B 12th ITC Specialist Seminar %C Lillehammer, Norway %D 2000 %P 13 - 25 %T Carrying wireless traffic in UMTS over IP using realtime transfer protocol multiplexing
• Measuring internet user traffic behavior dependent on access speed. Vicari, Norbert; Köhler, Stefan. In ITC Specialist Seminar on IP Traffic Measurement, Modeling and Management. Monterey, CA, USA, 2000.
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  @inproceedings{info3-inproceedings-2000-1, address = {Monterey, CA, USA}, author = {Vicari, Norbert and Köhler, Stefan}, booktitle = {ITC Specialist Seminar on IP Traffic Measurement, Modeling and Management}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Measuring internet user traffic behavior dependent on access speed}, year = 2000 }

  %0 Conference Paper %1 info3-inproceedings-2000-1 %A Vicari, Norbert %A Köhler, Stefan %B ITC Specialist Seminar on IP Traffic Measurement, Modeling and Management %C Monterey, CA, USA %D 2000 %T Measuring internet user traffic behavior dependent on access speed

• Simulation und Leistungsbewertung von Cluster Tools in der Halbleiterfertigung. Dümmler, Matthias. In 13. Symposium Simulationstechnik, pp. 73–78. 1999.
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  @inproceedings{info3-inproceedings-1999-19, author = {Dümmler, Matthias}, booktitle = {13. Symposium Simulationstechnik}, keywords = {sys:hidden:inproceedings}, pages = {73-78}, title = {Simulation und Leistungsbewertung von Cluster Tools in der Halbleiterfertigung}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-19 %A Dümmler, Matthias %B 13. Symposium Simulationstechnik %D 1999 %P 73-78 %T Simulation und Leistungsbewertung von Cluster Tools in der Halbleiterfertigung
• CONLOAD - a new lot release rule for semiconductor wafer fabs. Rose, Oliver. In Winter Simulation Conference ’99, pp. 850–855. Phoenix, AZ, 1999.
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  @inproceedings{info3-inproceedings-1999-12, address = {Phoenix, AZ}, author = {Rose, Oliver}, booktitle = {Winter Simulation Conference '99}, keywords = {sys:hidden:inproceedings}, pages = {850-855}, title = {CONLOAD - a new lot release rule for semiconductor wafer fabs}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-12 %A Rose, Oliver %B Winter Simulation Conference '99 %C Phoenix, AZ %D 1999 %P 850-855 %T CONLOAD - a new lot release rule for semiconductor wafer fabs
• Effects of variations in the available bandwidth on the performance of the GFR service. Vicari, Norbert. In Fifth Internetional Conference on Broadband Communications - BC’99, pp. 197–208. Hong Kong, China, 1999.
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  @inproceedings{info3-inproceedings-1999-6, address = {Hong Kong, China}, author = {Vicari, Norbert}, booktitle = {Fifth Internetional Conference on Broadband Communications - BC'99}, keywords = {sys:hidden:inproceedings}, pages = {197 - 208}, title = {Effects of variations in the available bandwidth on the performance of the GFR service}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-6 %A Vicari, Norbert %B Fifth Internetional Conference on Broadband Communications - BC'99 %C Hong Kong, China %D 1999 %P 197 - 208 %T Effects of variations in the available bandwidth on the performance of the GFR service
• Using discrete-time analysis in the performance analysis of manufacturing systems. Dümmler, Matthias; Schömig, Alexander. In International Conference on Semiconductor Manufacturing Operational Modeling and Simulation (SMOMS ’99), pp. 3–8. 1999.
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  @inproceedings{info3-inproceedings-1999-17, author = {Dümmler, Matthias and Schömig, Alexander}, booktitle = {International Conference on Semiconductor Manufacturing Operational Modeling and Simulation (SMOMS '99)}, keywords = {sys:hidden:inproceedings}, pages = {3-8}, title = {Using discrete-time analysis in the performance analysis of manufacturing systems}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-17 %A Dümmler, Matthias %A Schömig, Alexander %B International Conference on Semiconductor Manufacturing Operational Modeling and Simulation (SMOMS '99) %D 1999 %P 3-8 %T Using discrete-time analysis in the performance analysis of manufacturing systems
• Performance of the GFR-service with constant available bandwidth. Vicari, Norbert; Schedel, Robert. In IEEE INFOCOM’99, pp. 567–574. New York, USA, 1999.
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  @inproceedings{info3-inproceedings-1999-5, address = {New York, USA}, author = {Vicari, Norbert and Schedel, Robert}, booktitle = {IEEE INFOCOM'99}, keywords = {sys:hidden:inproceedings}, pages = {567 - 574}, title = {Performance of the GFR-service with constant available bandwidth}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-5 %A Vicari, Norbert %A Schedel, Robert %B IEEE INFOCOM'99 %C New York, USA %D 1999 %P 567 - 574 %T Performance of the GFR-service with constant available bandwidth
• Using simulation and genetic algorithms to improve cluster tool performance. Dümmler, Matthias. In Winter Simulation Conference 1999, pp. 875–879. 1999.
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  @inproceedings{info3-inproceedings-1999-18, author = {Dümmler, Matthias}, booktitle = {Winter Simulation Conference 1999}, keywords = {sys:hidden:inproceedings}, pages = {875-879}, title = {Using simulation and genetic algorithms to improve cluster tool performance}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-18 %A Dümmler, Matthias %B Winter Simulation Conference 1999 %D 1999 %P 875-879 %T Using simulation and genetic algorithms to improve cluster tool performance
• A Memory Markov Chain for VBR traffic with strong positive correlations. Rose, Oliver. In ITC 16, pp. 827–836. Edinburgh, GB, 1999.
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  @inproceedings{info3-inproceedings-1999-10, address = {Edinburgh, GB}, author = {Rose, Oliver}, booktitle = {ITC 16}, keywords = {sys:hidden:inproceedings}, pages = {827-836}, title = {A Memory Markov Chain for VBR traffic with strong positive correlations}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-10 %A Rose, Oliver %B ITC 16 %C Edinburgh, GB %D 1999 %P 827-836 %T A Memory Markov Chain for VBR traffic with strong positive correlations
• A framework for spatial traffic estimation and characterization in mobile communication network design. Tutschku, Kurt; Tran-Gia, Phuoc; Heuler, Marius. In 16th International Teletraffic Congress - ITC16, pp. 139–148. Edinburgh, UK, 1999.
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  @inproceedings{info3-inproceedings-1999-7, address = {Edinburgh, UK}, author = {Tutschku, Kurt and Tran-Gia, Phuoc and Heuler, Marius}, booktitle = {16th International Teletraffic Congress - ITC16}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = {139-148}, title = {A framework for spatial traffic estimation and characterization in mobile communication network design}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-7 %A Tutschku, Kurt %A Tran-Gia, Phuoc %A Heuler, Marius %B 16th International Teletraffic Congress - ITC16 %C Edinburgh, UK %D 1999 %P 139-148 %T A framework for spatial traffic estimation and characterization in mobile communication network design
• Teletraffic models and planning in wireless IP networks. Leibnitz, Kenji; Tran-Gia, Phuoc. In IEEE Wireless Communications and Networking Conference. New Orleans, USA, 1999.
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  @inproceedings{info3-inproceedings-1999-9, address = {New Orleans, USA}, author = {Leibnitz, Kenji and Tran-Gia, Phuoc}, booktitle = {IEEE Wireless Communications and Networking Conference}, keywords = {sys:hidden:inproceedings}, title = {Teletraffic models and planning in wireless IP networks}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-9 %A Leibnitz, Kenji %A Tran-Gia, Phuoc %B IEEE Wireless Communications and Networking Conference %C New Orleans, USA %D 1999 %T Teletraffic models and planning in wireless IP networks
• Estimation of the cycle time distribution of a wafer fab by a simple simulation model. Rose, Oliver. In SMOMS ’99 (1999 WMC), pp. 133–138. San Francisco, CA, 1999.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1999-11, address = {San Francisco, CA}, author = {Rose, Oliver}, booktitle = {SMOMS '99 (1999 WMC)}, keywords = {sys:hidden:inproceedings}, pages = {133-138}, title = {Estimation of the cycle time distribution of a wafer fab by a simple simulation model}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-11 %A Rose, Oliver %B SMOMS '99 (1999 WMC) %C San Francisco, CA %D 1999 %P 133-138 %T Estimation of the cycle time distribution of a wafer fab by a simple simulation model
• Interference minimization in wireless communication systems by optimal cell site selection. Tutschku, Kurt; Mathar, Rudolf; Niessen, Thomas. In 3rd European Personal Mobile Communication Conference (EPMCC’99), pp. 208–213. Paris, France, 1999.
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  @inproceedings{info3-inproceedings-1999-8, address = {Paris, France}, author = {Tutschku, Kurt and Mathar, Rudolf and Niessen, Thomas}, booktitle = {3rd European Personal Mobile Communication Conference (EPMCC'99)}, keywords = {sys:hidden:inproceedings}, month = {03}, pages = {208-213}, title = {Interference minimization in wireless communication systems by optimal cell site selection}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-8 %A Tutschku, Kurt %A Mathar, Rudolf %A Niessen, Thomas %B 3rd European Personal Mobile Communication Conference (EPMCC'99) %C Paris, France %D 1999 %P 208-213 %T Interference minimization in wireless communication systems by optimal cell site selection
• Adaptive soft-handoff thresholds for CDMA systems with spatial traffic. Remiche, Marie-Ange; Leibnitz, Kenji. In 16th International Teletraffic Congress, pp. 97–106. Edinburgh, UK, 1999.
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  @inproceedings{info3-inproceedings-1999-13, address = {Edinburgh, UK}, author = {Remiche, Marie-Ange and Leibnitz, Kenji}, booktitle = {16th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = {97-106}, title = {Adaptive soft-handoff thresholds for CDMA systems with spatial traffic}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-13 %A Remiche, Marie-Ange %A Leibnitz, Kenji %B 16th International Teletraffic Congress %C Edinburgh, UK %D 1999 %P 97-106 %T Adaptive soft-handoff thresholds for CDMA systems with spatial traffic
• Impact of clustered traffic distributions in CDMA radio network planning. Leibnitz, Kenji; Ehrenberger, Ulrich. In 16th International Teletraffic Congress, pp. 129–138. Edinburgh, UK, 1999.
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  @inproceedings{info3-inproceedings-1999-16, address = {Edinburgh, UK}, author = {Leibnitz, Kenji and Ehrenberger, Ulrich}, booktitle = {16th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = {129-138}, title = {Impact of clustered traffic distributions in CDMA radio network planning}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-16 %A Leibnitz, Kenji %A Ehrenberger, Ulrich %B 16th International Teletraffic Congress %C Edinburgh, UK %D 1999 %P 129-138 %T Impact of clustered traffic distributions in CDMA radio network planning
• A numerical framework for solving discrete finite Markov models applied to the AAL-2 protocol. Gerlich, Notker; Menth, Michael. In 10th GI/ITG Special Interest Conference (MMB’99). 1999.
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  @inproceedings{info3-inproceedings-1999-14, author = {Gerlich, Notker and Menth, Michael}, booktitle = {10th GI/ITG Special Interest Conference (MMB'99)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {A numerical framework for solving discrete finite Markov models applied to the AAL-2 protocol}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-14 %A Gerlich, Notker %A Menth, Michael %B 10th GI/ITG Special Interest Conference (MMB'99) %D 1999 %T A numerical framework for solving discrete finite Markov models applied to the AAL-2 protocol
• Impacts of Power Control on Outage Probabilities in CDMA Wireless Networks. Leibnitz, Kenji. In Proc. of IFIP 5th International Conference on Broadband Communications. Hong Kong, 1999.
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  @inproceedings{info3-inproceedings-1999-38, address = {Hong Kong}, author = {Leibnitz, Kenji}, booktitle = {Proc. of IFIP 5th International Conference on Broadband Communications}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Impacts of Power Control on Outage Probabilities in CDMA Wireless Networks}, year = 1999 }

  %0 Conference Paper %1 info3-inproceedings-1999-38 %A Leibnitz, Kenji %B Proc. of IFIP 5th International Conference on Broadband Communications %C Hong Kong %D 1999 %T Impacts of Power Control on Outage Probabilities in CDMA Wireless Networks

• Code division multiple access wireless network planning considering clustered spatial customer traffic. Leibnitz, Kenji; Jain, Nikhil; Tran-Gia, Phuoc. In 8th International Telecommunication Network Planning Symposium. Sorrento, Italy, 1998.
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  @inproceedings{info3-inproceedings-1998-25, address = {Sorrento, Italy}, author = {Leibnitz, Kenji and Jain, Nikhil and Tran-Gia, Phuoc}, booktitle = {8th International Telecommunication Network Planning Symposium}, keywords = {sys:hidden:inproceedings}, title = {Code division multiple access wireless network planning considering clustered spatial customer traffic}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-25 %A Leibnitz, Kenji %A Jain, Nikhil %A Tran-Gia, Phuoc %B 8th International Telecommunication Network Planning Symposium %C Sorrento, Italy %D 1998 %T Code division multiple access wireless network planning considering clustered spatial customer traffic
• Analysis of the dynamics of CDMA reverse link power control. Miller, John E.; Tran-Gia, Phuoc; Leibnitz, Kenji. In IEEE GLOBECOM 98. Sydney, Australia, 1998.
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  @inproceedings{info3-inproceedings-1998-27, address = {Sydney, Australia}, author = {Miller, John E. and Tran-Gia, Phuoc and Leibnitz, Kenji}, booktitle = {IEEE GLOBECOM 98}, keywords = {sys:hidden:inproceedings}, title = {Analysis of the dynamics of CDMA reverse link power control}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-27 %A Miller, John E. %A Tran-Gia, Phuoc %A Leibnitz, Kenji %B IEEE GLOBECOM 98 %C Sydney, Australia %D 1998 %T Analysis of the dynamics of CDMA reverse link power control
• Demand-based radio network planning of cellular communication systems. Tutschku, Kurt. In IEEE Infocom 98. San Francisco, CA, USA, 1998.
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  @inproceedings{info3-inproceedings-1998-23, address = {San Francisco, CA, USA}, author = {Tutschku, Kurt}, booktitle = {IEEE Infocom 98}, keywords = {sys:hidden:inproceedings}, title = {Demand-based radio network planning of cellular communication systems}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-23 %A Tutschku, Kurt %B IEEE Infocom 98 %C San Francisco, CA, USA %D 1998 %T Demand-based radio network planning of cellular communication systems
• WIP evolution of a semiconductor factory after a bottleneck workcenter breakdown. Rose, Oliver. In Winter Simulation Conference ’98. 1998.
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  @inproceedings{info3-inproceedings-1998-26, author = {Rose, Oliver}, booktitle = {Winter Simulation Conference '98}, keywords = {sys:hidden:inproceedings}, title = {WIP evolution of a semiconductor factory after a bottleneck workcenter breakdown}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-26 %A Rose, Oliver %B Winter Simulation Conference '98 %D 1998 %T WIP evolution of a semiconductor factory after a bottleneck workcenter breakdown
• Interference minimization in wireless communication systems by optimal cell site selection. Mathar, Rudolf; Tutschku, Kurt; Niessen, Thomas. In First Annual Report of the Center of Network Optimization. Würzburg, Germany, 1998.
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  @inproceedings{info3-inproceedings-1998-21, address = {Würzburg, Germany}, author = {Mathar, Rudolf and Tutschku, Kurt and Niessen, Thomas}, booktitle = {First Annual Report of the Center of Network Optimization}, keywords = {sys:hidden:inproceedings}, title = {Interference minimization in wireless communication systems by optimal cell site selection}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-21 %A Mathar, Rudolf %A Tutschku, Kurt %A Niessen, Thomas %B First Annual Report of the Center of Network Optimization %C Würzburg, Germany %D 1998 %T Interference minimization in wireless communication systems by optimal cell site selection
• The performance of aal-2 carrying CDMA voice traffic. Gerlich, Notker; Menth, Michael. In 11th International Teletraffic Congress Seminar. Yokohama, Japan, 1998.
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  @inproceedings{info3-inproceedings-1998-28, address = {Yokohama, Japan}, author = {Gerlich, Notker and Menth, Michael}, booktitle = {11th International Teletraffic Congress Seminar}, keywords = {sys:hidden:inproceedings}, title = {The performance of aal-2 carrying CDMA voice traffic}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-28 %A Gerlich, Notker %A Menth, Michael %B 11th International Teletraffic Congress Seminar %C Yokohama, Japan %D 1998 %T The performance of aal-2 carrying CDMA voice traffic
• Teletraffic issues in mobile communication network planning. Leibnitz, Kenji; Tutschku, Kurt; Tran-Gia, Phuoc. In 11th ITC Specialist Seminar. Yokohama, Japan, 1998.
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  @inproceedings{info3-inproceedings-1998-24, address = {Yokohama, Japan}, author = {Leibnitz, Kenji and Tutschku, Kurt and Tran-Gia, Phuoc}, booktitle = {11th ITC Specialist Seminar}, keywords = {sys:hidden:inproceedings}, title = {Teletraffic issues in mobile communication network planning}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-24 %A Leibnitz, Kenji %A Tutschku, Kurt %A Tran-Gia, Phuoc %B 11th ITC Specialist Seminar %C Yokohama, Japan %D 1998 %T Teletraffic issues in mobile communication network planning
• Models of WWW-traffic: a comparison of pareto and logarithmic histogram models. Vicari, Norbert. In 5th Polish Teletraffic Symposium / Project COPERNICUS 1463 ATMiN - Closing Seminar, pp. 2.2–1 . 1998.
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  @inproceedings{info3-inproceedings-1998-20, author = {Vicari, Norbert}, booktitle = {5th Polish Teletraffic Symposium / Project COPERNICUS 1463 ATMiN - Closing Seminar}, keywords = {sys:hidden:inproceedings}, pages = {2.2-1 - 2.2-12}, title = {Models of WWW-traffic: a comparison of pareto and logarithmic histogram models}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-20 %A Vicari, Norbert %B 5th Polish Teletraffic Symposium / Project COPERNICUS 1463 ATMiN - Closing Seminar %D 1998 %P 2.2-1 - 2.2-12 %T Models of WWW-traffic: a comparison of pareto and logarithmic histogram models
• The performance of base station interconnection alternatives in CDMA networks. Gerlich, Notker. In Networks’98. Sorrento, Italy, 1998.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1998-29, address = {Sorrento, Italy}, author = {Gerlich, Notker}, booktitle = {Networks'98}, keywords = {sys:hidden:inproceedings}, title = {The performance of base station interconnection alternatives in CDMA networks}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-29 %A Gerlich, Notker %B Networks'98 %C Sorrento, Italy %D 1998 %T The performance of base station interconnection alternatives in CDMA networks
• Code Division Multiple Access wireless network planning considering clustered spatial customer traffic. Leibnitz, Kenji; Tran-Gia, Phuoc; Jain, Nikhil. In 8th International Telecommunication Network Planning Symposium. Sorrento, Italy, 1998.
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  @inproceedings{info3-inproceedings-1998-163, address = {Sorrento, Italy}, author = {Leibnitz, Kenji and Tran-Gia, Phuoc and Jain, Nikhil}, booktitle = {8th International Telecommunication Network Planning Symposium}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Code Division Multiple Access wireless network planning considering clustered spatial customer traffic}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-163 %A Leibnitz, Kenji %A Tran-Gia, Phuoc %A Jain, Nikhil %B 8th International Telecommunication Network Planning Symposium %C Sorrento, Italy %D 1998 %T Code Division Multiple Access wireless network planning considering clustered spatial customer traffic
• Analysis of the Dynamics of CDMA Reverse Link Power Control. Leibnitz, Kenji; Tran-Gia, Phuoc; Miller, John E. In IEEE GLOBECOM. Sydney, Australia, 1998.
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  @inproceedings{info3-inproceedings-1998-162, address = {Sydney, Australia}, author = {Leibnitz, Kenji and Tran-Gia, Phuoc and Miller, John E.}, booktitle = {IEEE GLOBECOM}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Analysis of the Dynamics of CDMA Reverse Link Power Control}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-162 %A Leibnitz, Kenji %A Tran-Gia, Phuoc %A Miller, John E. %B IEEE GLOBECOM %C Sydney, Australia %D 1998 %T Analysis of the Dynamics of CDMA Reverse Link Power Control
• Interference minimization using automatic design of cellular communication networks. Tutschku, Kurt. In IEEE/VTS 48th Vehicular Technology Conference. Ottawa, Canada, 1998.
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  @inproceedings{info3-inproceedings-1998-22, address = {Ottawa, Canada}, author = {Tutschku, Kurt}, booktitle = {IEEE/VTS 48th Vehicular Technology Conference}, keywords = {sys:hidden:inproceedings}, title = {Interference minimization using automatic design of cellular communication networks}, year = 1998 }

  %0 Conference Paper %1 info3-inproceedings-1998-22 %A Tutschku, Kurt %B IEEE/VTS 48th Vehicular Technology Conference %C Ottawa, Canada %D 1998 %T Interference minimization using automatic design of cellular communication networks

• On cycle times and interdeparture times in semiconductor manufacturing. Gerlich, Notker; Rose, Oliver; Mittler, Manfred; Schömig, Alexander K. In Informs Fall 1997. Dallas, TX, USA, 1997.
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  @inproceedings{info3-inproceedings-1997-34, address = {Dallas, TX, USA}, author = {Gerlich, Notker and Rose, Oliver and Mittler, Manfred and Schömig, Alexander K.}, booktitle = {Informs Fall 1997}, keywords = {sys:hidden:inproceedings}, title = {On cycle times and interdeparture times in semiconductor manufacturing}, year = 1997 }

  %0 Conference Paper %1 info3-inproceedings-1997-34 %A Gerlich, Notker %A Rose, Oliver %A Mittler, Manfred %A Schömig, Alexander K. %B Informs Fall 1997 %C Dallas, TX, USA %D 1997 %T On cycle times and interdeparture times in semiconductor manufacturing
• On the spatial multiplexing gain of SDMA for wireless local loop access. Gerlich, Notker. In EPMCC’97, pp. 229–235. Bonn, Germany, 1997.
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  @inproceedings{info3-inproceedings-1997-36, address = {Bonn, Germany}, author = {Gerlich, Notker}, booktitle = {EPMCC'97}, keywords = {sys:hidden:inproceedings}, pages = {229-235}, title = {On the spatial multiplexing gain of SDMA for wireless local loop access}, year = 1997 }

  %0 Conference Paper %1 info3-inproceedings-1997-36 %A Gerlich, Notker %B EPMCC'97 %C Bonn, Germany %D 1997 %P 229-235 %T On the spatial multiplexing gain of SDMA for wireless local loop access
• ICEPT - an integrated cellular network planning tool. Leibnitz, Kenji; Tran-Gia, Phuoc; Tutschku, Kurt. In IEEE/VTS 47th Vehicular Technology Conference. Phoenix, AZ, USA, 1997.
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  @inproceedings{info3-inproceedings-1997-30, address = {Phoenix, AZ, USA}, author = {Leibnitz, Kenji and Tran-Gia, Phuoc and Tutschku, Kurt}, booktitle = {IEEE/VTS 47th Vehicular Technology Conference}, keywords = {sys:hidden:inproceedings}, title = {ICEPT - an integrated cellular network planning tool}, year = 1997 }

  %0 Conference Paper %1 info3-inproceedings-1997-30 %A Leibnitz, Kenji %A Tran-Gia, Phuoc %A Tutschku, Kurt %B IEEE/VTS 47th Vehicular Technology Conference %C Phoenix, AZ, USA %D 1997 %T ICEPT - an integrated cellular network planning tool
• Discrete-time analysis of batch servers with two job classes. Dümmler, Matthias; Schömig, Alexander K. In 1st World Congress on Systems Simulation. Singapore, 1997.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1997-37, address = {Singapore}, author = {Dümmler, Matthias and Schömig, Alexander K.}, booktitle = {1st World Congress on Systems Simulation}, keywords = {sys:hidden:inproceedings}, title = {Discrete-time analysis of batch servers with two job classes}, year = 1997 }

  %0 Conference Paper %1 info3-inproceedings-1997-37 %A Dümmler, Matthias %A Schömig, Alexander K. %B 1st World Congress on Systems Simulation %C Singapore %D 1997 %T Discrete-time analysis of batch servers with two job classes
• Congestion detection methods and their impact on the performance of the ABR flow control. Ritter, Michael. In 15th International Teletraffic Congress, pp. 1107–1118. Washington, D.C., USA, 1997.
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  @inproceedings{info3-inproceedings-1997-32, address = {Washington, D.C., USA}, author = {Ritter, Michael}, booktitle = {15th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, pages = {1107-1118}, title = {Congestion detection methods and their impact on the performance of the ABR flow control}, year = 1997 }

  %0 Conference Paper %1 info3-inproceedings-1997-32 %A Ritter, Michael %B 15th International Teletraffic Congress %C Washington, D.C., USA %D 1997 %P 1107-1118 %T Congestion detection methods and their impact on the performance of the ABR flow control
• The effect of bottleneck service rate variations on the performance of the ABR flow control. Ritter, Michael. In IEEE INFOCOM ’97, pp. 816–823. Kobe, Japan, 1997.
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  @inproceedings{info3-inproceedings-1997-31, address = {Kobe, Japan}, author = {Ritter, Michael}, booktitle = {IEEE INFOCOM '97}, keywords = {sys:hidden:inproceedings}, pages = {816-823}, title = {The effect of bottleneck service rate variations on the performance of the ABR flow control}, year = 1997 }

  %0 Conference Paper %1 info3-inproceedings-1997-31 %A Ritter, Michael %B IEEE INFOCOM '97 %C Kobe, Japan %D 1997 %P 816-823 %T The effect of bottleneck service rate variations on the performance of the ABR flow control
• Performance analysis of link carrying capacity in CDMA systems. Tran-Gia, Phuoc; Gerlich, Notker; Jain, Nikhil; Elsayed, Khaled. In 15th International Teletraffic Congress, pp. 1159–1168. Washington, D.C., USA, 1997.
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  @inproceedings{info3-inproceedings-1997-35, address = {Washington, D.C., USA}, author = {Tran-Gia, Phuoc and Gerlich, Notker and Jain, Nikhil and Elsayed, Khaled}, booktitle = {15th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = {1159-1168}, title = {Performance analysis of link carrying capacity in CDMA systems}, year = 1997 }

  %0 Conference Paper %1 info3-inproceedings-1997-35 %A Tran-Gia, Phuoc %A Gerlich, Notker %A Jain, Nikhil %A Elsayed, Khaled %B 15th International Teletraffic Congress %C Washington, D.C., USA %D 1997 %P 1159-1168 %T Performance analysis of link carrying capacity in CDMA systems

• Determination of traffic descriptors for VPs carrying delay-sensitive traffic. Ritter, Michael; Garcia, Jorge. In Proceedings of Broadband Communications ’96, pp. 3–1. Montreal, QB, Canada, 1996.
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  @inproceedings{info3-inproceedings-1996-105, address = {Montreal, QB, Canada}, author = {Ritter, Michael and Garcia, Jorge}, booktitle = {Proceedings of Broadband Communications '96}, keywords = {sys:hidden:inproceedings}, month = {04}, pages = {3-1-5}, title = {Determination of traffic descriptors for VPs carrying delay-sensitive traffic}, year = 1996 }

  %0 Conference Paper %1 info3-inproceedings-1996-105 %A Ritter, Michael %A Garcia, Jorge %B Proceedings of Broadband Communications '96 %C Montreal, QB, Canada %D 1996 %P 3-1-5 %T Determination of traffic descriptors for VPs carrying delay-sensitive traffic
• Discrete-time approximation of the machine interference model with generally distributed failure, repair, and walking times. Mittler, Manfred; Kern, Christoph. In Rensselare’s 5th International Conference Computer Integrated Manufacturing and Automation Technology 1996 (CIMAT ’96), C. Foulard and R. David, editors, pp. 236–241. Grenoble, France, 1996.
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  @inproceedings{info3-inproceedings-1996-104, address = {Grenoble, France}, author = {Mittler, Manfred and Kern, Christoph}, booktitle = {Rensselare's 5th International Conference Computer Integrated Manufacturing and Automation Technology 1996 (CIMAT '96), C. Foulard and R. David, editors}, keywords = {sys:hidden:inproceedings}, pages = {236-241}, title = {Discrete-time approximation of the machine interference model with generally distributed failure, repair, and walking times}, year = 1996 }

  %0 Conference Paper %1 info3-inproceedings-1996-104 %A Mittler, Manfred %A Kern, Christoph %B Rensselare's 5th International Conference Computer Integrated Manufacturing and Automation Technology 1996 (CIMAT '96), C. Foulard and R. David, editors %C Grenoble, France %D 1996 %P 236-241 %T Discrete-time approximation of the machine interference model with generally distributed failure, repair, and walking times
• Network buffer requirements of the rate-based control mechanism for ABR services. Ritter, Michael. In Proceedings of the IEEE INFOCOM 96, pp. pp. 1190–1197. San Francisco, CA, U.S.A., 1996.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1996-106, address = {San Francisco, CA, U.S.A.}, author = {Ritter, Michael}, booktitle = {Proceedings of the IEEE INFOCOM 96}, keywords = {sys:hidden:inproceedings}, month = {03}, pages = {pp. 1190-1197}, title = {Network buffer requirements of the rate-based control mechanism for ABR services}, year = 1996 }

  %0 Conference Paper %1 info3-inproceedings-1996-106 %A Ritter, Michael %B Proceedings of the IEEE INFOCOM 96 %C San Francisco, CA, U.S.A. %D 1996 %P pp. 1190-1197 %T Network buffer requirements of the rate-based control mechanism for ABR services
• Fast Ray-Tracing for Field Strength Prediction in Cellular Mobile Network Planning. Tutschku, Kurt; Leibnitz, Kenji. In 46th IEEE/VTS Conference on Vehicular Technology 1996. Atlanta, USA, 1996.
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  @inproceedings{info3-inproceedings-1996-60, address = {Atlanta, USA}, author = {Tutschku, Kurt and Leibnitz, Kenji}, booktitle = {46th IEEE/VTS Conference on Vehicular Technology 1996}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Fast Ray-Tracing for Field Strength Prediction in Cellular Mobile Network Planning}, year = 1996 }

  %0 Conference Paper %1 info3-inproceedings-1996-60 %A Tutschku, Kurt %A Leibnitz, Kenji %B 46th IEEE/VTS Conference on Vehicular Technology 1996 %C Atlanta, USA %D 1996 %T Fast Ray-Tracing for Field Strength Prediction in Cellular Mobile Network Planning
• An Integrated Approach to Cellular Network Planning. Gerlich, Notker; Tutschku, Kurt; Tran-Gia, Phuoc. In of the 7th International Telecommunication Network Planning Symposium (Networks ’96). Sydney, Australia, 1996.
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  @inproceedings{info3-inproceedings-1996-61, address = {Sydney, Australia}, author = {Gerlich, Notker and Tutschku, Kurt and Tran-Gia, Phuoc}, booktitle = {of the 7th International Telecommunication Network Planning Symposium (Networks '96)}, keywords = {sys:hidden:inproceedings}, month = 11, title = {An Integrated Approach to Cellular Network Planning}, year = 1996 }

  %0 Conference Paper %1 info3-inproceedings-1996-61 %A Gerlich, Notker %A Tutschku, Kurt %A Tran-Gia, Phuoc %B of the 7th International Telecommunication Network Planning Symposium (Networks '96) %C Sydney, Australia %D 1996 %T An Integrated Approach to Cellular Network Planning
• Discrete-time analysis of batch servers with bounded idle time. Schömig, Alexander K.; Tran-Gia, Phuoc. In Proceedings of the European Simulation Multiconference 1996. Budapest, Hungary, 1996.
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  @inproceedings{info3-inproceedings-1996-103, address = {Budapest, Hungary}, author = {Schömig, Alexander K. and Tran-Gia, Phuoc}, booktitle = {Proceedings of the European Simulation Multiconference 1996}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Discrete-time analysis of batch servers with bounded idle time}, year = 1996 }

  %0 Conference Paper %1 info3-inproceedings-1996-103 %A Schömig, Alexander K. %A Tran-Gia, Phuoc %B Proceedings of the European Simulation Multiconference 1996 %C Budapest, Hungary %D 1996 %T Discrete-time analysis of batch servers with bounded idle time
• A survey on the application of self-organizing neural nets to different rating-scale data of Parkinson patients. Fritsch, Thomas; Kraus, Peter H.; Neuner, Bernd; Klotz, Peter. In Proceedings of the International Conference EANN’96, pp. pp. 419–423. London, England, 1996.
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  @inproceedings{info3-inproceedings-1996-102, address = {London, England}, author = {Fritsch, Thomas and Kraus, Peter H. and Neuner, Bernd and Klotz, Peter}, booktitle = {Proceedings of the International Conference EANN'96}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = {pp. 419-423}, title = {A survey on the application of self-organizing neural nets to different rating-scale data of Parkinson patients}, year = 1996 }

  %0 Conference Paper %1 info3-inproceedings-1996-102 %A Fritsch, Thomas %A Kraus, Peter H. %A Neuner, Bernd %A Klotz, Peter %B Proceedings of the International Conference EANN'96 %C London, England %D 1996 %P pp. 419-423 %T A survey on the application of self-organizing neural nets to different rating-scale data of Parkinson patients
• Analysis of feedback-oriented congestion control mechanisms for ABR services. Ritter, Michael. In ITC Specialists Seminar ’96, pp. pp. 291–308. Lund, Sweden, 1996.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1996-101, address = {Lund, Sweden}, author = {Ritter, Michael}, booktitle = {ITC Specialists Seminar '96}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {pp. 291-308}, title = {Analysis of feedback-oriented congestion control mechanisms for ABR services}, year = 1996 }

  %0 Conference Paper %1 info3-inproceedings-1996-101 %A Ritter, Michael %B ITC Specialists Seminar '96 %C Lund, Sweden %D 1996 %P pp. 291-308 %T Analysis of feedback-oriented congestion control mechanisms for ABR services
• Two-moment analysis of alternative tool models with random breakdowns. Mittler, Manfred. In IEEE International Conference on Emerging Technologies and Factory Automation (ETFA ’96). Kauai, HI, U.S.A., 1996.
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  @inproceedings{info3-inproceedings-1996-100, address = {Kauai, HI, U.S.A.}, author = {Mittler, Manfred}, booktitle = {IEEE International Conference on Emerging Technologies and Factory Automation (ETFA '96)}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Two-moment analysis of alternative tool models with random breakdowns}, year = 1996 }

  %0 Conference Paper %1 info3-inproceedings-1996-100 %A Mittler, Manfred %B IEEE International Conference on Emerging Technologies and Factory Automation (ETFA '96) %C Kauai, HI, U.S.A. %D 1996 %T Two-moment analysis of alternative tool models with random breakdowns

• On the approximation of higher moments in open and closed fork/join primitives with limited buffers. Mittler, Manfred; Ono-Tesfaye, Tarik; Schömig, Alexander K. In Symposium on Operations Research (SOR ’95), P. Kleinschmidt, A. Bachem, U. Derigs, D. Fischer, U. Leopold-Wildburger, R. Möhring, editors, pp. pp. 113–118. Passau, Germany, 1995.
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  @inproceedings{info3-inproceedings-1995-114, address = {Passau, Germany}, author = {Mittler, Manfred and Ono-Tesfaye, Tarik and Schömig, Alexander K.}, booktitle = {Symposium on Operations Research (SOR '95), P. Kleinschmidt, A. Bachem, U. Derigs, D. Fischer, U. Leopold-Wildburger, R. Möhring, editors}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {pp. 113-118}, title = {On the approximation of higher moments in open and closed fork/join primitives with limited buffers}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-114 %A Mittler, Manfred %A Ono-Tesfaye, Tarik %A Schömig, Alexander K. %B Symposium on Operations Research (SOR '95), P. Kleinschmidt, A. Bachem, U. Derigs, D. Fischer, U. Leopold-Wildburger, R. Möhring, editors %C Passau, Germany %D 1995 %P pp. 113-118 %T On the approximation of higher moments in open and closed fork/join primitives with limited buffers
• Impact of MPEG video traffic on an ATM multiplexer. Frater, Michael R; Rose, Oliver. In High Performance Networking VI, R. Puigjaner, editor, pp. pp. 157–168. London, 1995.
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  @inproceedings{info3-inproceedings-1995-120, address = {London}, author = {Frater, Michael R and Rose, Oliver}, booktitle = {High Performance Networking VI, R. Puigjaner, editor}, keywords = {sys:hidden:inproceedings}, pages = {pp. 157-168}, title = {Impact of MPEG video traffic on an ATM multiplexer}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-120 %A Frater, Michael R %A Rose, Oliver %B High Performance Networking VI, R. Puigjaner, editor %C London %D 1995 %P pp. 157-168 %T Impact of MPEG video traffic on an ATM multiplexer
• Field Strength Prediction by Ray-Tracing for Adaptive Base Station Positioning in Mobile Communication Networks. Tutschku, Kurt; Leibnitz, Kenji; Fritsch, Thomas. In 2. ITG Fachtagung Mobile Kommunikation, p. ITG-Fachbericht 135. Neu-Ulm ,Germany, 1995.
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  @inproceedings{info3-inproceedings-1995-59, address = {Neu-Ulm ,Germany}, author = {Tutschku, Kurt and Leibnitz, Kenji and Fritsch, Thomas}, booktitle = {2. ITG Fachtagung Mobile Kommunikation}, keywords = {sys:hidden:inproceedings}, pages = {ITG-Fachbericht 135}, title = {Field Strength Prediction by Ray-Tracing for Adaptive Base Station Positioning in Mobile Communication Networks}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-59 %A Tutschku, Kurt %A Leibnitz, Kenji %A Fritsch, Thomas %B 2. ITG Fachtagung Mobile Kommunikation %C Neu-Ulm ,Germany %D 1995 %P ITG-Fachbericht 135 %T Field Strength Prediction by Ray-Tracing for Adaptive Base Station Positioning in Mobile Communication Networks
• A self-organizing neural net clustering Parkinson patients and control persons using motor data. Kraus, Peter H.; Fritsch, Thomas; Klotz, Peter; Neuner, Bernd. In Proceedings of the 8th IEEE Symposium on Computer-Based Medical Systems. Lubbock, TX, U.S.A., 1995.
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  @inproceedings{info3-inproceedings-1995-119, address = {Lubbock, TX, U.S.A.}, author = {Kraus, Peter H. and Fritsch, Thomas and Klotz, Peter and Neuner, Bernd}, booktitle = {Proceedings of the 8th IEEE Symposium on Computer-Based Medical Systems}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {A self-organizing neural net clustering Parkinson patients and control persons using motor data}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-119 %A Kraus, Peter H. %A Fritsch, Thomas %A Klotz, Peter %A Neuner, Bernd %B Proceedings of the 8th IEEE Symposium on Computer-Based Medical Systems %C Lubbock, TX, U.S.A. %D 1995 %T A self-organizing neural net clustering Parkinson patients and control persons using motor data
• Reducing the variance of cycle times in semiconductor manufacturing systems. Gerlich, Notker; Schömig, Alexander K.; Mittler, Manfred. In International Conference on Improving Manufacturing Performance in a Disributed Enterprise: Advanced Systems and Tools, pp. pp. 89–98. Edinburgh, Scotland, 1995.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1995-117, address = {Edinburgh, Scotland}, author = {Gerlich, Notker and Schömig, Alexander K. and Mittler, Manfred}, booktitle = {International Conference on Improving Manufacturing Performance in a Disributed Enterprise: Advanced Systems and Tools}, keywords = {sys:hidden:inproceedings}, month = {07}, pages = {pp. 89-98}, title = {Reducing the variance of cycle times in semiconductor manufacturing systems}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-117 %A Gerlich, Notker %A Schömig, Alexander K. %A Mittler, Manfred %B International Conference on Improving Manufacturing Performance in a Disributed Enterprise: Advanced Systems and Tools %C Edinburgh, Scotland %D 1995 %P pp. 89-98 %T Reducing the variance of cycle times in semiconductor manufacturing systems
• On transfer blocking and minimal blocking in serial manufacturing systems - the impact of buffer allocation. Schömig, Alexander K. In 17th IFIP TC7 Conference on System Modelling and Optimization, p. Abstracts Vol. 1. Prague, Czech Republic, 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-118, address = {Prague, Czech Republic}, author = {Schömig, Alexander K.}, booktitle = {17th IFIP TC7 Conference on System Modelling and Optimization}, keywords = {sys:hidden:inproceedings}, month = {07}, pages = {Abstracts Vol. 1}, title = {On transfer blocking and minimal blocking in serial manufacturing systems - the impact of buffer allocation}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-118 %A Schömig, Alexander K. %B 17th IFIP TC7 Conference on System Modelling and Optimization %C Prague, Czech Republic %D 1995 %P Abstracts Vol. 1 %T On transfer blocking and minimal blocking in serial manufacturing systems - the impact of buffer allocation
• A Note on the Application of Marie`s Method for Queueing Networks with Batch Servers. Kahnt, Matthias; Schömig, Alexander K. In Symposium on Operations Research (SOR’95). Passau, Germany, 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-116, address = {Passau, Germany}, author = {Kahnt, Matthias and Schömig, Alexander K.}, booktitle = {Symposium on Operations Research (SOR'95)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {A Note on the Application of Marie`s Method for Queueing Networks with Batch Servers}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-116 %A Kahnt, Matthias %A Schömig, Alexander K. %B Symposium on Operations Research (SOR'95) %C Passau, Germany %D 1995 %T A Note on the Application of Marie`s Method for Queueing Networks with Batch Servers
• Are artificial neural nets able to provide internal representation of external learning patterns? A question, still remaining open. Fritsch, Thomas. In Proceedings of the International Conference on Brain processes, theories and Models. Las Palmas de Gran Canaria, Spain, 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-109, address = {Las Palmas de Gran Canaria, Spain}, author = {Fritsch, Thomas}, booktitle = {Proceedings of the International Conference on Brain processes, theories and Models}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Are artificial neural nets able to provide internal representation of external learning patterns? A question, still remaining open.}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-109 %A Fritsch, Thomas %B Proceedings of the International Conference on Brain processes, theories and Models %C Las Palmas de Gran Canaria, Spain %D 1995 %T Are artificial neural nets able to provide internal representation of external learning patterns? A question, still remaining open.
• Towards a Channel Allocation Scheme for SDMA-based Mobile Communication Systems. Gerlich, Notker; Tangemann, Michael. In Proceedings of the 2nd ITG Conference on Mobile Communication ’95. Neu-Ulm, Germany, 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-113, address = {Neu-Ulm, Germany}, author = {Gerlich, Notker and Tangemann, Michael}, booktitle = {Proceedings of the 2nd ITG Conference on Mobile Communication '95}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Towards a Channel Allocation Scheme for SDMA-based Mobile Communication Systems}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-113 %A Gerlich, Notker %A Tangemann, Michael %B Proceedings of the 2nd ITG Conference on Mobile Communication '95 %C Neu-Ulm, Germany %D 1995 %T Towards a Channel Allocation Scheme for SDMA-based Mobile Communication Systems
• Performance Modelling of Pull Manufacturing Systems with Batch Servers. Schömig, Alexander K.; Kahnt, Matthias. In Proceedings of the 1995 Symposium on Emerging Technologies and Factory Automation (ETFA ’95), pp. volume 3, pp. 175–18. Paris, France, 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-112, address = {Paris, France}, author = {Schömig, Alexander K. and Kahnt, Matthias}, booktitle = {Proceedings of the 1995 Symposium on Emerging Technologies and Factory Automation (ETFA '95)}, keywords = {sys:hidden:inproceedings}, month = 10, pages = {volume 3, pp. 175-18}, title = {Performance Modelling of Pull Manufacturing Systems with Batch Servers}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-112 %A Schömig, Alexander K. %A Kahnt, Matthias %B Proceedings of the 1995 Symposium on Emerging Technologies and Factory Automation (ETFA '95) %C Paris, France %D 1995 %P volume 3, pp. 175-18 %T Performance Modelling of Pull Manufacturing Systems with Batch Servers
• Performance comparison of design alternatives for source policing devices in ATM systems. Ritter, Michael; Hübner, Frank; Kornprobst, Stefan. In Proceedings of the 20th IEEE Conference on Local Computer Networks, pp. pp. 132–139. Minneapolis, MN, U.S.A., 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-110, address = {Minneapolis, MN, U.S.A.}, author = {Ritter, Michael and Hübner, Frank and Kornprobst, Stefan}, booktitle = {Proceedings of the 20th IEEE Conference on Local Computer Networks}, keywords = {sys:hidden:inproceedings}, month = 10, pages = {pp. 132-139}, title = {Performance comparison of design alternatives for source policing devices in ATM systems.}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-110 %A Ritter, Michael %A Hübner, Frank %A Kornprobst, Stefan %B Proceedings of the 20th IEEE Conference on Local Computer Networks %C Minneapolis, MN, U.S.A. %D 1995 %P pp. 132-139 %T Performance comparison of design alternatives for source policing devices in ATM systems.
• Statistical properties of MPEG video traffic and their impact on traffic modeling in ATM systems. Rose, Oliver. In Proceedings of the 20th Annual Conference on Local Computer Networks, pp. pp. 397–406. 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-111, author = {Rose, Oliver}, booktitle = {Proceedings of the 20th Annual Conference on Local Computer Networks}, keywords = {sys:hidden:inproceedings}, month = 10, pages = {pp. 397-406}, title = {Statistical properties of MPEG video traffic and their impact on traffic modeling in ATM systems.}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-111 %A Rose, Oliver %B Proceedings of the 20th Annual Conference on Local Computer Networks %D 1995 %P pp. 397-406 %T Statistical properties of MPEG video traffic and their impact on traffic modeling in ATM systems.
• Autocorrelation of cycle times in semiconductor manufacturing systems. Schömig, Alexander K.; Mittler, Manfred. In Proceedingsof the Winter Simulation Conference 1995, C. Alexopolous, K. Kang, W. R. Lilegdon and D. Goldsman, editors, pp. pp. 865–872. Washington, DC, U.S.A., 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-108, address = {Washington, DC, U.S.A.}, author = {Schömig, Alexander K. and Mittler, Manfred}, booktitle = {Proceedingsof the Winter Simulation Conference 1995, C. Alexopolous, K. Kang, W. R. Lilegdon and D. Goldsman, editors}, keywords = {sys:hidden:inproceedings}, month = 12, pages = {pp. 865-872}, title = {Autocorrelation of cycle times in semiconductor manufacturing systems}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-108 %A Schömig, Alexander K. %A Mittler, Manfred %B Proceedingsof the Winter Simulation Conference 1995, C. Alexopolous, K. Kang, W. R. Lilegdon and D. Goldsman, editors %C Washington, DC, U.S.A. %D 1995 %P pp. 865-872 %T Autocorrelation of cycle times in semiconductor manufacturing systems
• Set management: Minimizing synchronization delays of prefabricated parts before assembly. Gihr, Ottmar; Purm, Michael; Mittler, Manfred. In Proceedingsof the Winter Simulation Conference 1995, C. Alexopolous, K. Kang, W. R. Lilegdon and D. Goldsman, editors, pp. pp. 829–836. Washington, DC, U.S.A., 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-107, address = {Washington, DC, U.S.A.}, author = {Gihr, Ottmar and Purm, Michael and Mittler, Manfred}, booktitle = {Proceedingsof the Winter Simulation Conference 1995, C. Alexopolous, K. Kang, W. R. Lilegdon and D. Goldsman, editors}, keywords = {sys:hidden:inproceedings}, month = 12, pages = {pp. 829-836}, title = {Set management: Minimizing synchronization delays of prefabricated parts before assembly}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-107 %A Gihr, Ottmar %A Purm, Michael %A Mittler, Manfred %B Proceedingsof the Winter Simulation Conference 1995, C. Alexopolous, K. Kang, W. R. Lilegdon and D. Goldsman, editors %C Washington, DC, U.S.A. %D 1995 %P pp. 829-836 %T Set management: Minimizing synchronization delays of prefabricated parts before assembly
• Performance analysis of the dual cell spacer in ATM systems. Ritter, Michael. In Proceedings of the IFIP 6th International Conference on High Performance Networking, pp. pp. 345–362. Palma de Mallorca, Spain, 1995.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1995-115, address = {Palma de Mallorca, Spain}, author = {Ritter, Michael}, booktitle = {Proceedings of the IFIP 6th International Conference on High Performance Networking}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {pp. 345-362}, title = {Performance analysis of the dual cell spacer in ATM systems}, year = 1995 }

  %0 Conference Paper %1 info3-inproceedings-1995-115 %A Ritter, Michael %B Proceedings of the IFIP 6th International Conference on High Performance Networking %C Palma de Mallorca, Spain %D 1995 %P pp. 345-362 %T Performance analysis of the dual cell spacer in ATM systems

• Fluctuations of biological rhythms: Self-organized ritcality and predicatability?. Tran-Gia, Phuoc; Braun, Christian; Klusch, Andreas; Kniffki, Klaus-D. In ICASSE. Erlangen, Germany, 1994.
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  @inproceedings{info3-inproceedings-1994-185, address = {Erlangen, Germany}, author = {Tran-Gia, Phuoc and Braun, Christian and Klusch, Andreas and Kniffki, Klaus-D.}, booktitle = {ICASSE}, keywords = {sys:hidden:inproceedings}, title = {Fluctuations of biological rhythms: Self-organized ritcality and predicatability?}, year = 1994 }

  %0 Conference Paper %1 info3-inproceedings-1994-185 %A Tran-Gia, Phuoc %A Braun, Christian %A Klusch, Andreas %A Kniffki, Klaus-D. %B ICASSE %C Erlangen, Germany %D 1994 %T Fluctuations of biological rhythms: Self-organized ritcality and predicatability?
• A comparison of models for VBR video traffic sources in B-ISDN. Rose, Oliver; Frater, Michael R. In IFIP Transactions C-24: Broadband Communications, II, pp. pp. 275–287. North-Holland, Amsterdam, 1994.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1994-127, address = {North-Holland, Amsterdam}, author = {Rose, Oliver and Frater, Michael R}, booktitle = {IFIP Transactions C-24: Broadband Communications, II}, keywords = {sys:hidden:inproceedings}, pages = {pp. 275-287}, title = {A comparison of models for VBR video traffic sources in B-ISDN}, year = 1994 }

  %0 Conference Paper %1 info3-inproceedings-1994-127 %A Rose, Oliver %A Frater, Michael R %B IFIP Transactions C-24: Broadband Communications, II %C North-Holland, Amsterdam %D 1994 %P pp. 275-287 %T A comparison of models for VBR video traffic sources in B-ISDN
• Performance analysis of a batch service system. Frötschl, Bernhard; Gold, Hermann. In Proc. 14th International Teletraffic Congress (ITC 14), J. Labetoulle and J. W. Roberts, editors, pp. pp. 155–168. Antibes Juanles-Pins, France, 1994.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1994-126, address = {Antibes Juanles-Pins, France}, author = {Frötschl, Bernhard and Gold, Hermann}, booktitle = {Proc. 14th International Teletraffic Congress (ITC 14), J. Labetoulle and J. W. Roberts, editors}, keywords = {sys:hidden:inproceedings}, pages = {pp. 155-168}, title = {Performance analysis of a batch service system}, year = 1994 }

  %0 Conference Paper %1 info3-inproceedings-1994-126 %A Frötschl, Bernhard %A Gold, Hermann %B Proc. 14th International Teletraffic Congress (ITC 14), J. Labetoulle and J. W. Roberts, editors %C Antibes Juanles-Pins, France %D 1994 %P pp. 155-168 %T Performance analysis of a batch service system
• Non linear evaluation of rating scales using artificial neural nets. Fritsch, Thomas; Tran-Gia, Phuoc; Kraus, Peter H.; Klotz, Peter; Przuntek, Horst. In 3rd International Congress of Movement Disorders. Orlando, FL, U.S.A., 1994.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1994-123, address = {Orlando, FL, U.S.A.}, author = {Fritsch, Thomas and Tran-Gia, Phuoc and Kraus, Peter H. and Klotz, Peter and Przuntek, Horst}, booktitle = {3rd International Congress of Movement Disorders}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Non linear evaluation of rating scales using artificial neural nets}, year = 1994 }

  %0 Conference Paper %1 info3-inproceedings-1994-123 %A Fritsch, Thomas %A Tran-Gia, Phuoc %A Kraus, Peter H. %A Klotz, Peter %A Przuntek, Horst %B 3rd International Congress of Movement Disorders %C Orlando, FL, U.S.A. %D 1994 %T Non linear evaluation of rating scales using artificial neural nets
• Slot-Reuse in High-Speed Communication Networks. Dittmann, Rainer. In EFOC&N’94. Heidelberg, Germany, 1994.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1994-125, address = {Heidelberg, Germany}, author = {Dittmann, Rainer}, booktitle = {EFOC&N'94}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Slot-Reuse in High-Speed Communication Networks}, year = 1994 }

  %0 Conference Paper %1 info3-inproceedings-1994-125 %A Dittmann, Rainer %B EFOC&N'94 %C Heidelberg, Germany %D 1994 %T Slot-Reuse in High-Speed Communication Networks
• Using Kanban in a Semiconductor Fabrication Environment - a Simulation Study. Schömig, Alexander K. In Annual meeting of the Production and Operation Management Society. Washington, DC, U.S.A., 1994.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1994-124, address = {Washington, DC, U.S.A.}, author = {Schömig, Alexander K.}, booktitle = {Annual meeting of the Production and Operation Management Society}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Using Kanban in a Semiconductor Fabrication Environment - a Simulation Study}, year = 1994 }

  %0 Conference Paper %1 info3-inproceedings-1994-124 %A Schömig, Alexander K. %B Annual meeting of the Production and Operation Management Society %C Washington, DC, U.S.A. %D 1994 %T Using Kanban in a Semiconductor Fabrication Environment - a Simulation Study
• Performance of a cell rate monitoring mechanisms in ATM systems. Ritter, Michael; Tran-Gia, Phuoc. In International Conference on Local and Metropolitan Communication Systems, T. Hasegawa, G. Pujolle, H. Takagi and Y. Takahashi, editors, pp. pp. 119–139. Kyoto, Japan, 1994.
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  @inproceedings{info3-inproceedings-1994-121, address = {Kyoto, Japan}, author = {Ritter, Michael and Tran-Gia, Phuoc}, booktitle = {International Conference on Local and Metropolitan Communication Systems, T. Hasegawa, G. Pujolle, H. Takagi and Y. Takahashi, editors}, keywords = {sys:hidden:inproceedings}, month = 12, pages = {pp. 119-139}, title = {Performance of a cell rate monitoring mechanisms in ATM systems}, year = 1994 }

  %0 Conference Paper %1 info3-inproceedings-1994-121 %A Ritter, Michael %A Tran-Gia, Phuoc %B International Conference on Local and Metropolitan Communication Systems, T. Hasegawa, G. Pujolle, H. Takagi and Y. Takahashi, editors %C Kyoto, Japan %D 1994 %P pp. 119-139 %T Performance of a cell rate monitoring mechanisms in ATM systems
• MPEG-video sources in ATM-systems - a new approach for the dimensioning of policing functions. Rose, Oliver; Ritter, Michael. In International Conference on Local and Metropolitan Communication Systems, T. Hasegawa, G. Pujolle, H. Takagi and Y. Takahashi, editors, pp. pp. 99–117. Kyoto, Japan, 1994.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1994-122, address = {Kyoto, Japan}, author = {Rose, Oliver and Ritter, Michael}, booktitle = {International Conference on Local and Metropolitan Communication Systems, T. Hasegawa, G. Pujolle, H. Takagi and Y. Takahashi, editors}, keywords = {sys:hidden:inproceedings}, month = 12, pages = {pp. 99-117}, title = {MPEG-video sources in ATM-systems - a new approach for the dimensioning of policing functions}, year = 1994 }

  %0 Conference Paper %1 info3-inproceedings-1994-122 %A Rose, Oliver %A Ritter, Michael %B International Conference on Local and Metropolitan Communication Systems, T. Hasegawa, G. Pujolle, H. Takagi and Y. Takahashi, editors %C Kyoto, Japan %D 1994 %P pp. 99-117 %T MPEG-video sources in ATM-systems - a new approach for the dimensioning of policing functions

• An analysis of trunk reservation and grade-of-service balancing mechanisms in multiservice broadband networks. Hübner, Frank; Tran-Gia, Phuoc. In IFIP-TC6 Workshop on Modelling and Performance Evaluation of ATM Technology. La Martinique, 1993.
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  @inproceedings{info3-inproceedings-1993-82, address = {La Martinique}, author = {Hübner, Frank and Tran-Gia, Phuoc}, booktitle = {IFIP-TC6 Workshop on Modelling and Performance Evaluation of ATM Technology}, keywords = {sys:hidden:inproceedings}, month = {01}, title = {An analysis of trunk reservation and grade-of-service balancing mechanisms in multiservice broadband networks}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-82 %A Hübner, Frank %A Tran-Gia, Phuoc %B IFIP-TC6 Workshop on Modelling and Performance Evaluation of ATM Technology %C La Martinique %D 1993 %T An analysis of trunk reservation and grade-of-service balancing mechanisms in multiservice broadband networks
• Classification of Parkinson rating-scale-data using a self-organizing neural net. Fritsch, Thomas; Kraus, Peter H.; Tran-Gia, Phuoc; Przuntek, Horst. In Int. Conf. on Neural Networks. San Francisco, CA, U.S.A., 1993.
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  @inproceedings{info3-inproceedings-1993-81, address = {San Francisco, CA, U.S.A.}, author = {Fritsch, Thomas and Kraus, Peter H. and Tran-Gia, Phuoc and Przuntek, Horst}, booktitle = {Int. Conf. on Neural Networks}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Classification of Parkinson rating-scale-data using a self-organizing neural net}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-81 %A Fritsch, Thomas %A Kraus, Peter H. %A Tran-Gia, Phuoc %A Przuntek, Horst %B Int. Conf. on Neural Networks %C San Francisco, CA, U.S.A. %D 1993 %T Classification of Parkinson rating-scale-data using a self-organizing neural net
• An integrated approach to cellular mobile communication planning using traffic data prestructured by a self-organizing feature map. Fritsch, Thomas; Hanshans, Stefan. In 1993 IEEE International Conference on Neural Networks, p. pp. 822D-822I. San Francisco, CA, U.S.A., 1993.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-1993-134, address = {San Francisco, CA, U.S.A.}, author = {Fritsch, Thomas and Hanshans, Stefan}, booktitle = {1993 IEEE International Conference on Neural Networks}, keywords = {sys:hidden:inproceedings}, month = {03}, pages = {pp. 822D-822I}, title = {An integrated approach to cellular mobile communication planning using traffic data prestructured by a self-organizing feature map}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-134 %A Fritsch, Thomas %A Hanshans, Stefan %B 1993 IEEE International Conference on Neural Networks %C San Francisco, CA, U.S.A. %D 1993 %P pp. 822D-822I %T An integrated approach to cellular mobile communication planning using traffic data prestructured by a self-organizing feature map
• Performance of a neural net scheduler used in packet switching interconnection networks. Tran-Gia, Phuoc; Mittler, Manfred. In Int. Conf. on Neural Networks. San Francisco, CA, U.S.A., 1993.
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  @inproceedings{info3-inproceedings-1993-80, address = {San Francisco, CA, U.S.A.}, author = {Tran-Gia, Phuoc and Mittler, Manfred}, booktitle = {Int. Conf. on Neural Networks}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Performance of a neural net scheduler used in packet switching interconnection networks}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-80 %A Tran-Gia, Phuoc %A Mittler, Manfred %B Int. Conf. on Neural Networks %C San Francisco, CA, U.S.A. %D 1993 %T Performance of a neural net scheduler used in packet switching interconnection networks
• Leistungsuntersuchung von Schedulingverfahren in Produktionssystemen. Gihr, Ottmar; Schömig, Alexander K. In Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen. Kurzberichte und Werkzeugvorstellungen, B. Walke and O. Spaniol, editors. 7. ITG/GI-Fachtagung, pp. pp. 74–85. Aachen, Germany, 1993.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1993-131, address = {Aachen, Germany}, author = {Gihr, Ottmar and Schömig, Alexander K.}, booktitle = {Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen. Kurzberichte und Werkzeugvorstellungen, B. Walke and O. Spaniol, editors. 7. ITG/GI-Fachtagung}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {pp. 74-85}, title = {Leistungsuntersuchung von Schedulingverfahren in Produktionssystemen}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-131 %A Gihr, Ottmar %A Schömig, Alexander K. %B Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen. Kurzberichte und Werkzeugvorstellungen, B. Walke and O. Spaniol, editors. 7. ITG/GI-Fachtagung %C Aachen, Germany %D 1993 %P pp. 74-85 %T Leistungsuntersuchung von Schedulingverfahren in Produktionssystemen
• Basic concepts and performance of high-speed protocols. Tran-Gia, Phuoc; Stock, Thomas. In Conference on Integrated Broadband Communication Networks and Services. Copenhagen, The Netherlands (?), 1993.
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  @inproceedings{info3-inproceedings-1993-133, address = {Copenhagen, The Netherlands (?)}, author = {Tran-Gia, Phuoc and Stock, Thomas}, booktitle = {Conference on Integrated Broadband Communication Networks and Services}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Basic concepts and performance of high-speed protocols}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-133 %A Tran-Gia, Phuoc %A Stock, Thomas %B Conference on Integrated Broadband Communication Networks and Services %C Copenhagen, The Netherlands (?) %D 1993 %T Basic concepts and performance of high-speed protocols
• Analysis of two finite queues coupled by a triggering scheduler. Mittler, Manfred. In Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen. Kurzberichte und Werkzeugvorstellungen, B. Walke and O. Spaniol, editors. 7. ITG/GI-Fachtagung, pp. pp. 136–145. Aachen, Germany, 1993.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1993-130, address = {Aachen, Germany}, author = {Mittler, Manfred}, booktitle = {Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen. Kurzberichte und Werkzeugvorstellungen, B. Walke and O. Spaniol, editors. 7. ITG/GI-Fachtagung}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {pp. 136-145}, title = {Analysis of two finite queues coupled by a triggering scheduler}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-130 %A Mittler, Manfred %B Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen. Kurzberichte und Werkzeugvorstellungen, B. Walke and O. Spaniol, editors. 7. ITG/GI-Fachtagung %C Aachen, Germany %D 1993 %P pp. 136-145 %T Analysis of two finite queues coupled by a triggering scheduler
• Blocking in multi-service broadband systems with CBR and VBR input traffic. Hübner, Frank; Ritter, Michael. In Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen, B. Walke and O. Spaniol, editors, 7. ITG/GI-Fachtagung, pp. pp. 74–85. Aachen, Germany, 1993.
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  @inproceedings{info3-inproceedings-1993-129, address = {Aachen, Germany}, author = {Hübner, Frank and Ritter, Michael}, booktitle = {Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen, B. Walke and O. Spaniol, editors, 7. ITG/GI-Fachtagung}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {pp. 74-85}, title = {Blocking in multi-service broadband systems with CBR and VBR input traffic}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-129 %A Hübner, Frank %A Ritter, Michael %B Messung, Modellierung und Bewertung von Rechen- und Kommunikationssystemen, B. Walke and O. Spaniol, editors, 7. ITG/GI-Fachtagung %C Aachen, Germany %D 1993 %P pp. 74-85 %T Blocking in multi-service broadband systems with CBR and VBR input traffic
• Discrete-time analysis technique and application to usage parameter control modelling in ATM systems. Tran-Gia, Phuoc. In Proceedings of the 8th Australian Teletraffic Research Seminar. Melbourne, Australia, 1993.
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  @inproceedings{info3-inproceedings-1993-128, address = {Melbourne, Australia}, author = {Tran-Gia, Phuoc}, booktitle = {Proceedings of the 8th Australian Teletraffic Research Seminar}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Discrete-time analysis technique and application to usage parameter control modelling in ATM systems}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-128 %A Tran-Gia, Phuoc %B Proceedings of the 8th Australian Teletraffic Research Seminar %C Melbourne, Australia %D 1993 %T Discrete-time analysis technique and application to usage parameter control modelling in ATM systems
• Autocorrelation and power density spectrum of ATM multiplexer output processes. Hübner, Frank. In Conference on Applied Probability in Engineering, Computer and Communication Sciences. Paris, France, 1993.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1993-132, address = {Paris, France}, author = {Hübner, Frank}, booktitle = {Conference on Applied Probability in Engineering, Computer and Communication Sciences}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Autocorrelation and power density spectrum of ATM multiplexer output processes}, year = 1993 }

  %0 Conference Paper %1 info3-inproceedings-1993-132 %A Hübner, Frank %B Conference on Applied Probability in Engineering, Computer and Communication Sciences %C Paris, France %D 1993 %T Autocorrelation and power density spectrum of ATM multiplexer output processes

• Performance of a neural net used as admission controller in ATM systems. Tran-Gia, Phuoc; Gropp (Rose), Oliver. In Globecom ’92. Orlando, FL, U.S.A., 1992.
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  @inproceedings{info3-inproceedings-1992-83, address = {Orlando, FL, U.S.A.}, author = {Tran-Gia, Phuoc and Gropp (Rose), Oliver}, booktitle = {Globecom '92}, keywords = {sys:hidden:inproceedings}, month = 12, title = {Performance of a neural net used as admission controller in ATM systems}, year = 1992 }

  %0 Conference Paper %1 info3-inproceedings-1992-83 %A Tran-Gia, Phuoc %A Gropp (Rose), Oliver %B Globecom '92 %C Orlando, FL, U.S.A. %D 1992 %T Performance of a neural net used as admission controller in ATM systems
• Analytische Modellbildung von Fertigungssystemen - Eine Fallstudie. Gihr, Ottmar; Gold, Hermann. In 22. GI-Jahrestagung. Karlsruhe, 1992.
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  @inproceedings{info3-inproceedings-1992-85, address = {Karlsruhe}, author = {Gihr, Ottmar and Gold, Hermann}, booktitle = {22. GI-Jahrestagung}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Analytische Modellbildung von Fertigungssystemen - Eine Fallstudie}, year = 1992 }

  %0 Conference Paper %1 info3-inproceedings-1992-85 %A Gihr, Ottmar %A Gold, Hermann %B 22. GI-Jahrestagung %C Karlsruhe %D 1992 %T Analytische Modellbildung von Fertigungssystemen - Eine Fallstudie
• Classification of rating-scale-data using an artificial neural net. Fritsch, Thomas; Kraus, Peter H.; Tran-Gia, Phuoc; Przuntek, Horst. In Journal of Neurology, Supplement 3 to Vol. 239, Abstracts of the 65th Congress of the German Society of Neurology, pp. pp. 23–26. Saarbrücken, 1992.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-1992-84, address = {Saarbrücken}, author = {Fritsch, Thomas and Kraus, Peter H. and Tran-Gia, Phuoc and Przuntek, Horst}, booktitle = {Journal of Neurology, Supplement 3 to Vol. 239, Abstracts of the 65th Congress of the German Society of Neurology}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {pp. 23-26}, title = {Classification of rating-scale-data using an artificial neural net}, year = 1992 }

  %0 Conference Paper %1 info3-inproceedings-1992-84 %A Fritsch, Thomas %A Kraus, Peter H. %A Tran-Gia, Phuoc %A Przuntek, Horst %B Journal of Neurology, Supplement 3 to Vol. 239, Abstracts of the 65th Congress of the German Society of Neurology %C Saarbrücken %D 1992 %P pp. 23-26 %T Classification of rating-scale-data using an artificial neural net
• Architecture alternatives and performance issues in DQDB subnetwork interconnection. Dittmann, Rainer; Tran-Gia, Phuoc. In Proc. EFOC/LAN’92, pp. pp. 229–234. Paris, Frankreich, 1992.
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  @inproceedings{info3-inproceedings-1992-86, address = {Paris, Frankreich}, author = {Dittmann, Rainer and Tran-Gia, Phuoc}, booktitle = {Proc. EFOC/LAN'92}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = {pp. 229-234}, title = {Architecture alternatives and performance issues in DQDB subnetwork interconnection}, year = 1992 }

  %0 Conference Paper %1 info3-inproceedings-1992-86 %A Dittmann, Rainer %A Tran-Gia, Phuoc %B Proc. EFOC/LAN'92 %C Paris, Frankreich %D 1992 %P pp. 229-234 %T Architecture alternatives and performance issues in DQDB subnetwork interconnection

• Quasi-stationary analysis of a finite-capacity asynchronous multiplexer with modulated deterministic input. Hübner, Frank; Tran-Gia, Phuoc. In Proceedings of the 13th International Teletraffic Congress, ITC13. Kopenhagen, Dänemark, 1991.
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  @inproceedings{info3-inproceedings-1991-91, address = {Kopenhagen, Dänemark}, author = {Hübner, Frank and Tran-Gia, Phuoc}, booktitle = {Proceedings of the 13th International Teletraffic Congress, ITC13}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Quasi-stationary analysis of a finite-capacity asynchronous multiplexer with modulated deterministic input}, year = 1991 }

  %0 Conference Paper %1 info3-inproceedings-1991-91 %A Hübner, Frank %A Tran-Gia, Phuoc %B Proceedings of the 13th International Teletraffic Congress, ITC13 %C Kopenhagen, Dänemark %D 1991 %T Quasi-stationary analysis of a finite-capacity asynchronous multiplexer with modulated deterministic input
• A layered description of ATM cell traffic streams and correlation analysis. Tran-Gia, Phuoc; Gihr, Ottmar. In Proc. IEEE INFOCOM ’91. Florida, U.S.A., 1991.
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  @inproceedings{info3-inproceedings-1991-93, address = {Florida, U.S.A.}, author = {Tran-Gia, Phuoc and Gihr, Ottmar}, booktitle = {Proc. IEEE INFOCOM '91}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {A layered description of ATM cell traffic streams and correlation analysis}, year = 1991 }

  %0 Conference Paper %1 info3-inproceedings-1991-93 %A Tran-Gia, Phuoc %A Gihr, Ottmar %B Proc. IEEE INFOCOM '91 %C Florida, U.S.A. %D 1991 %T A layered description of ATM cell traffic streams and correlation analysis
• Influences of multiple priorities on DQDB protocol performance. Teletraffic and datatraffic in a period of change. Stock, Thomas. In Proceedings of the 13th International Teletraffic Congress, ITC13. Kopenhagen, Dänemark, 1991.
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  @inproceedings{info3-inproceedings-1991-90, address = {Kopenhagen, Dänemark}, author = {Stock, Thomas}, booktitle = {Proceedings of the 13th International Teletraffic Congress, ITC13}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Influences of multiple priorities on DQDB protocol performance. Teletraffic and datatraffic in a period of change}, year = 1991 }

  %0 Conference Paper %1 info3-inproceedings-1991-90 %A Stock, Thomas %B Proceedings of the 13th International Teletraffic Congress, ITC13 %C Kopenhagen, Dänemark %D 1991 %T Influences of multiple priorities on DQDB protocol performance. Teletraffic and datatraffic in a period of change
• Analysis of the IEEE 802.6 DQDB access protocol. Stock, Thomas; Dittmann, Rainer. In Proc. 2nd Joint Workshop on High Speed Networks. Stuttgart, 1991.
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  @inproceedings{info3-inproceedings-1991-88, address = {Stuttgart}, author = {Stock, Thomas and Dittmann, Rainer}, booktitle = {Proc. 2nd Joint Workshop on High Speed Networks}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Analysis of the IEEE 802.6 DQDB access protocol}, year = 1991 }

  %0 Conference Paper %1 info3-inproceedings-1991-88 %A Stock, Thomas %A Dittmann, Rainer %B Proc. 2nd Joint Workshop on High Speed Networks %C Stuttgart %D 1991 %T Analysis of the IEEE 802.6 DQDB access protocol
• Multi server batch service systems in push and pull operation mode. Hübner, Frank; Gold, Hermann. In 11th European Congress on Operational Research. RWTH Aachen, 1991.
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  @inproceedings{info3-inproceedings-1991-89, address = {RWTH Aachen}, author = {Hübner, Frank and Gold, Hermann}, booktitle = {11th European Congress on Operational Research}, keywords = {sys:hidden:inproceedings}, month = {07}, title = {Multi server batch service systems in push and pull operation mode}, year = 1991 }

  %0 Conference Paper %1 info3-inproceedings-1991-89 %A Hübner, Frank %A Gold, Hermann %B 11th European Congress on Operational Research %C RWTH Aachen %D 1991 %T Multi server batch service systems in push and pull operation mode
• Performance analysis of the CRMA-protocol in high-speed networks. Tran-Gia, Phuoc; Dittmann, Rainer. In Proc. International Conf. on the Performance of Distributed Systems and Integrated Comm. Networks. Kyoto, Japan, 1991.
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  @inproceedings{info3-inproceedings-1991-92, address = {Kyoto, Japan}, author = {Tran-Gia, Phuoc and Dittmann, Rainer}, booktitle = {Proc. International Conf. on the Performance of Distributed Systems and Integrated Comm. Networks}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Performance analysis of the CRMA-protocol in high-speed networks}, year = 1991 }

  %0 Conference Paper %1 info3-inproceedings-1991-92 %A Tran-Gia, Phuoc %A Dittmann, Rainer %B Proc. International Conf. on the Performance of Distributed Systems and Integrated Comm. Networks %C Kyoto, Japan %D 1991 %T Performance analysis of the CRMA-protocol in high-speed networks
• Communication network routing using neural nets - numerical aspects and alternative approaches. Fritsch, Thomas; Mandel, Wolfgang. In International Joint Conference on Neural Networks, pp. Vol. 1, pp. 1178–118. Singapur, 1991.
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  @inproceedings{info3-inproceedings-1991-87, address = {Singapur}, author = {Fritsch, Thomas and Mandel, Wolfgang}, booktitle = {International Joint Conference on Neural Networks}, keywords = {sys:hidden:inproceedings}, month = 11, pages = {Vol. 1, pp. 1178-118}, title = {Communication network routing using neural nets - numerical aspects and alternative approaches}, year = 1991 }

  %0 Conference Paper %1 info3-inproceedings-1991-87 %A Fritsch, Thomas %A Mandel, Wolfgang %B International Joint Conference on Neural Networks %C Singapur %D 1991 %P Vol. 1, pp. 1178-118 %T Communication network routing using neural nets - numerical aspects and alternative approaches

• Analysis of a finite-capacity asynchronous multiplexer with deterministic traffic sources. Hübner, Frank. In 7th International Teletraffic Congress Specialist Seminar. Morristown, NJ, U.S.A., 1990.
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  @inproceedings{info3-inproceedings-1990-94, address = {Morristown, NJ, U.S.A.}, author = {Hübner, Frank}, booktitle = {7th International Teletraffic Congress Specialist Seminar}, keywords = {sys:hidden:inproceedings}, month = 10, title = {Analysis of a finite-capacity asynchronous multiplexer with deterministic traffic sources}, year = 1990 }

  %0 Conference Paper %1 info3-inproceedings-1990-94 %A Hübner, Frank %B 7th International Teletraffic Congress Specialist Seminar %C Morristown, NJ, U.S.A. %D 1990 %T Analysis of a finite-capacity asynchronous multiplexer with deterministic traffic sources
• A discrete-time analysis of the DQDB access protocol with general input traffic. Stock, Thomas; Tran-Gia, Phuoc. In Proc SBT/IEEE International Telecommunications Symposium (ITS’90), pp. pp. 6.4.1–6. Rio de Janeiro, Brasilien, 1990.
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  @inproceedings{info3-inproceedings-1990-95, address = {Rio de Janeiro, Brasilien}, author = {Stock, Thomas and Tran-Gia, Phuoc}, booktitle = {Proc SBT/IEEE International Telecommunications Symposium (ITS'90)}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {pp. 6.4.1-6}, title = {A discrete-time analysis of the DQDB access protocol with general input traffic}, year = 1990 }

  %0 Conference Paper %1 info3-inproceedings-1990-95 %A Stock, Thomas %A Tran-Gia, Phuoc %B Proc SBT/IEEE International Telecommunications Symposium (ITS'90) %C Rio de Janeiro, Brasilien %D 1990 %P pp. 6.4.1-6 %T A discrete-time analysis of the DQDB access protocol with general input traffic
• Modelling of the DQDB access protocol and closed-form approximation. Stock, Thomas; Tran-Gia, Phuoc. In Proc. NATO Advanced Research Workshop: "Architecture and performance of high-capacity LANs and MANs", INRIA. Sophia Antipolis, Frankreich, 1990.
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  @inproceedings{info3-inproceedings-1990-96, address = {Sophia Antipolis, Frankreich}, author = {Stock, Thomas and Tran-Gia, Phuoc}, booktitle = {Proc. NATO Advanced Research Workshop: "Architecture and performance of high-capacity LANs and MANs", INRIA}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Modelling of the DQDB access protocol and closed-form approximation}, year = 1990 }

  %0 Conference Paper %1 info3-inproceedings-1990-96 %A Stock, Thomas %A Tran-Gia, Phuoc %B Proc. NATO Advanced Research Workshop: "Architecture and performance of high-capacity LANs and MANs", INRIA %C Sophia Antipolis, Frankreich %D 1990 %T Modelling of the DQDB access protocol and closed-form approximation
• Anwendung neuronaler Netze in Kommunikationssystemen. Tran-Gia, Phuoc; Gold, Hermann. In Workshop "Neuronale Netze". Bonn, Germany, 1990.
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  @inproceedings{info3-inproceedings-1990-166, address = {Bonn, Germany}, author = {Tran-Gia, Phuoc and Gold, Hermann}, booktitle = {Workshop "Neuronale Netze"}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {Anwendung neuronaler Netze in Kommunikationssystemen}, year = 1990 }

  %0 Conference Paper %1 info3-inproceedings-1990-166 %A Tran-Gia, Phuoc %A Gold, Hermann %B Workshop "Neuronale Netze" %C Bonn, Germany %D 1990 %T Anwendung neuronaler Netze in Kommunikationssystemen

• Anwendung zeitdiskreter Transformationen in der Nachrichtenverkehrstheorie. Tran-Gia, Phuoc. In ITG-Fachtagung Stochastische Modelle und Methoden in der Informationstechnik. Nürnberg, 1989.
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  @inproceedings{info3-inproceedings-1989-99, address = {Nürnberg}, author = {Tran-Gia, Phuoc}, booktitle = {ITG-Fachtagung Stochastische Modelle und Methoden in der Informationstechnik}, keywords = {sys:hidden:inproceedings}, month = {04}, title = {Anwendung zeitdiskreter Transformationen in der Nachrichtenverkehrstheorie}, year = 1989 }

  %0 Conference Paper %1 info3-inproceedings-1989-99 %A Tran-Gia, Phuoc %B ITG-Fachtagung Stochastische Modelle und Methoden in der Informationstechnik %C Nürnberg %D 1989 %T Anwendung zeitdiskreter Transformationen in der Nachrichtenverkehrstheorie
• Approximate performance analysis of the DQDB access protocol. Tran-Gia, Phuoc; Stock, Thomas. In Proc. Traffic Theories for New Telecommunications Services. Proceedings of the ITC specialists seminar. Adelaide, Australien, 1989.
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  @inproceedings{info3-inproceedings-1989-98, address = {Adelaide, Australien}, author = {Tran-Gia, Phuoc and Stock, Thomas}, booktitle = {Proc. Traffic Theories for New Telecommunications Services. Proceedings of the ITC specialists seminar}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Approximate performance analysis of the DQDB access protocol}, year = 1989 }

  %0 Conference Paper %1 info3-inproceedings-1989-98 %A Tran-Gia, Phuoc %A Stock, Thomas %B Proc. Traffic Theories for New Telecommunications Services. Proceedings of the ITC specialists seminar %C Adelaide, Australien %D 1989 %T Approximate performance analysis of the DQDB access protocol
• Throughput analysis of a class of selective repeat protocols in high-speed environments. Tran-Gia, Phuoc; Ahmadi, Hojat; Kermani, Parviz. In Proc. GLOBECOM’89. Dallas, TX, U.S.A., 1989.
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  @inproceedings{info3-inproceedings-1989-97, address = {Dallas, TX, U.S.A.}, author = {Tran-Gia, Phuoc and Ahmadi, Hojat and Kermani, Parviz}, booktitle = {Proc. GLOBECOM'89}, keywords = {sys:hidden:inproceedings}, month = 11, title = {Throughput analysis of a class of selective repeat protocols in high-speed environments}, year = 1989 }

  %0 Conference Paper %1 info3-inproceedings-1989-97 %A Tran-Gia, Phuoc %A Ahmadi, Hojat %A Kermani, Parviz %B Proc. GLOBECOM'89 %C Dallas, TX, U.S.A. %D 1989 %T Throughput analysis of a class of selective repeat protocols in high-speed environments

• Analysis of a Discrete-Time G[X]/D/1-S Queueing Systems with Applications in Packet Switching Systems. Ahmadi, Hojat; Tran-Gia, Phuoc. In IEEE INFOCOM. New Orleans, USA, 1988.
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  @inproceedings{info3-inproceedings-1988-168, address = {New Orleans, USA}, author = {Ahmadi, Hojat and Tran-Gia, Phuoc}, booktitle = {IEEE INFOCOM}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {Analysis of a Discrete-Time G[X]/D/1-S Queueing Systems with Applications in Packet Switching Systems}, year = 1988 }

  %0 Conference Paper %1 info3-inproceedings-1988-168 %A Ahmadi, Hojat %A Tran-Gia, Phuoc %B IEEE INFOCOM %C New Orleans, USA %D 1988 %T Analysis of a Discrete-Time G[X]/D/1-S Queueing Systems with Applications in Packet Switching Systems
• Analysis of a Load-driven Overload Control Mechanism in Discrete-Time Domain. Tran-Gia, Phuoc. In 12th International Teletraffic Congress. Torino, Italy, 1988.
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  @inproceedings{info3-inproceedings-1988-167, address = {Torino, Italy}, author = {Tran-Gia, Phuoc}, booktitle = {12th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Analysis of a Load-driven Overload Control Mechanism in Discrete-Time Domain}, year = 1988 }

  %0 Conference Paper %1 info3-inproceedings-1988-167 %A Tran-Gia, Phuoc %B 12th International Teletraffic Congress %C Torino, Italy %D 1988 %T Analysis of a Load-driven Overload Control Mechanism in Discrete-Time Domain

• discrete-Time Analysis of Polling Systems with Renewal Inputs. Tran-Gia, Phuoc. In 3rd Int. Conf. on Data Comm. Systems and their Performance, pp. 495–510. Rio de Janeiro, Brazil, 1987.
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  @inproceedings{info3-inproceedings-1987-169, address = {Rio de Janeiro, Brazil}, author = {Tran-Gia, Phuoc}, booktitle = {3rd Int. Conf. on Data Comm. Systems and their Performance}, keywords = {sys:hidden:inproceedings}, month = {06}, pages = {495-510}, title = {discrete-Time Analysis of Polling Systems with Renewal Inputs}, year = 1987 }

  %0 Conference Paper %1 info3-inproceedings-1987-169 %A Tran-Gia, Phuoc %B 3rd Int. Conf. on Data Comm. Systems and their Performance %C Rio de Janeiro, Brazil %D 1987 %P 495-510 %T discrete-Time Analysis of Polling Systems with Renewal Inputs
• UNES - A Universal Enviroment Simulator for Real-Time Tests of SPC Switching Systems. Lemppenau, Wolfram; Tran-Gia, Phuoc. In International Switching Symposium. Phoenix, USA, 1987.
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  @inproceedings{info3-inproceedings-1987-171, address = {Phoenix, USA}, author = {Lemppenau, Wolfram and Tran-Gia, Phuoc}, booktitle = {International Switching Symposium}, keywords = {sys:hidden:inproceedings}, month = {03}, title = {UNES - A Universal Enviroment Simulator for Real-Time Tests of SPC Switching Systems}, year = 1987 }

  %0 Conference Paper %1 info3-inproceedings-1987-171 %A Lemppenau, Wolfram %A Tran-Gia, Phuoc %B International Switching Symposium %C Phoenix, USA %D 1987 %T UNES - A Universal Enviroment Simulator for Real-Time Tests of SPC Switching Systems
• Performance Analysis of Semidynamic Scheduling Strategies in Discrete-Time Domain. Tran-Gia, Phuoc; Rathgeb, Erwin. In INFOCOM, pp. 962–970. San Francisco, USA, 1987.
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  @inproceedings{info3-inproceedings-1987-170, address = {San Francisco, USA}, author = {Tran-Gia, Phuoc and Rathgeb, Erwin}, booktitle = {INFOCOM}, keywords = {sys:hidden:inproceedings}, pages = {962-970}, title = {Performance Analysis of Semidynamic Scheduling Strategies in Discrete-Time Domain}, year = 1987 }

  %0 Conference Paper %1 info3-inproceedings-1987-170 %A Tran-Gia, Phuoc %A Rathgeb, Erwin %B INFOCOM %C San Francisco, USA %D 1987 %P 962-970 %T Performance Analysis of Semidynamic Scheduling Strategies in Discrete-Time Domain

• Performance Analysis of Polling Mechanisms with Receiver Blocking. Tran-Gia, Phuoc; Raith, Thomas. In ICCC, pp. 577–582. München, Deutschland, 1986.
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  @inproceedings{info3-inproceedings-1986-172, address = {München, Deutschland}, author = {Tran-Gia, Phuoc and Raith, Thomas}, booktitle = {ICCC}, keywords = {sys:hidden:inproceedings}, month = {09}, pages = {577-582}, title = {Performance Analysis of Polling Mechanisms with Receiver Blocking}, year = 1986 }

  %0 Conference Paper %1 info3-inproceedings-1986-172 %A Tran-Gia, Phuoc %A Raith, Thomas %B ICCC %C München, Deutschland %D 1986 %P 577-582 %T Performance Analysis of Polling Mechanisms with Receiver Blocking
• Dependency of Service Time on Waiting Time in Switching Systems - A Queueing Analysis with Aspects of Overload Control. Tran-Gia, Phuoc; Van Hoorn, Michiel H. In IEEE Transactions on Communications Vol. com-34, no. 4, pp. 357–364. 1986.
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  @inproceedings{info3-inproceedings-1986-186, author = {Tran-Gia, Phuoc and Van Hoorn, Michiel H.}, booktitle = {IEEE Transactions on Communications Vol. com-34, no. 4}, keywords = {sys:hidden:inproceedings}, month = {04}, pages = {357-364}, title = {Dependency of Service Time on Waiting Time in Switching Systems - A Queueing Analysis with Aspects of Overload Control}, year = 1986 }

  %0 Conference Paper %1 info3-inproceedings-1986-186 %A Tran-Gia, Phuoc %A Van Hoorn, Michiel H. %B IEEE Transactions on Communications Vol. com-34, no. 4 %D 1986 %P 357-364 %T Dependency of Service Time on Waiting Time in Switching Systems - A Queueing Analysis with Aspects of Overload Control
• Discrete Time Analysis of the Interdeparture Distribution of GI/G/1 Queues. Tran-Gia, Phuoc. In Int. Seminar on Teletraffic Analysis and Computer Performance Evaluation, pp. 341–357. Amsterdam, Niederlande, 1986.
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  @inproceedings{info3-inproceedings-1986-173, address = {Amsterdam, Niederlande}, author = {Tran-Gia, Phuoc}, booktitle = {Int. Seminar on Teletraffic Analysis and Computer Performance Evaluation}, keywords = {sys:hidden:inproceedings}, pages = {341-357}, title = {Discrete Time Analysis of the Interdeparture Distribution of GI/G/1 Queues.}, year = 1986 }

  %0 Conference Paper %1 info3-inproceedings-1986-173 %A Tran-Gia, Phuoc %B Int. Seminar on Teletraffic Analysis and Computer Performance Evaluation %C Amsterdam, Niederlande %D 1986 %P 341-357 %T Discrete Time Analysis of the Interdeparture Distribution of GI/G/1 Queues.
• Functional Testing and Testing under Load Conditions of Real-Time Software in SPC Switching Systems by a Universal Environment Simulator. Lemppenau, Wolfram; Tran-Gia, Phuoc; Daniel, W.; Friedel, H.; Lehnert, R. In 6th Int. Conf. on Software Eng. for Telecommunication Switching Systems. Eindhoven, Niederlande, 1986.
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  @inproceedings{info3-inproceedings-1986-174, address = {Eindhoven, Niederlande}, author = {Lemppenau, Wolfram and Tran-Gia, Phuoc and Daniel, W. and Friedel, H. and Lehnert, R.}, booktitle = {6th Int. Conf. on Software Eng. for Telecommunication Switching Systems}, keywords = {sys:hidden:inproceedings}, title = {Functional Testing and Testing under Load Conditions of Real-Time Software in SPC Switching Systems by a Universal Environment Simulator}, year = 1986 }

  %0 Conference Paper %1 info3-inproceedings-1986-174 %A Lemppenau, Wolfram %A Tran-Gia, Phuoc %A Daniel, W. %A Friedel, H. %A Lehnert, R. %B 6th Int. Conf. on Software Eng. for Telecommunication Switching Systems %C Eindhoven, Niederlande %D 1986 %T Functional Testing and Testing under Load Conditions of Real-Time Software in SPC Switching Systems by a Universal Environment Simulator

• Approximation for Finite Capacity Multiqueue Systems. Tran-Gia, Phuoc; Raith, Thomas. In Conf. on Measurement, Modelling and Evaluation of Computer Systems. Dortmund, Germany, 1985.
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  @inproceedings{info3-inproceedings-1985-175, address = {Dortmund, Germany}, author = {Tran-Gia, Phuoc and Raith, Thomas}, booktitle = {Conf. on Measurement, Modelling and Evaluation of Computer Systems}, keywords = {sys:hidden:inproceedings}, title = {Approximation for Finite Capacity Multiqueue Systems}, year = 1985 }

  %0 Conference Paper %1 info3-inproceedings-1985-175 %A Tran-Gia, Phuoc %A Raith, Thomas %B Conf. on Measurement, Modelling and Evaluation of Computer Systems %C Dortmund, Germany %D 1985 %T Approximation for Finite Capacity Multiqueue Systems
• A Universal Environment Simulator for SPC Switching System Testing. Tran-Gia, Phuoc; Lemppenau, Wolfram. In 11th International Teletraffic Congress, p. 5.1B-3. Kyoto, 1985.
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  @inproceedings{info3-inproceedings-1985-177, address = {Kyoto}, author = {Tran-Gia, Phuoc and Lemppenau, Wolfram}, booktitle = {11th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, pages = {5.1B-3}, title = {A Universal Environment Simulator for SPC Switching System Testing}, year = 1985 }

  %0 Conference Paper %1 info3-inproceedings-1985-177 %A Tran-Gia, Phuoc %A Lemppenau, Wolfram %B 11th International Teletraffic Congress %C Kyoto %D 1985 %P 5.1B-3 %T A Universal Environment Simulator for SPC Switching System Testing
• Multiqueue Systems with Finite Capacity and Nonexhaustive Cyclic Service. Raith, Thomas; Tran-Gia, Phuoc. In International Seminar on Computer Networking and Performance Evaluation. Tokyo, Japan, 1985.
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  @inproceedings{info3-inproceedings-1985-176, address = {Tokyo, Japan}, author = {Raith, Thomas and Tran-Gia, Phuoc}, booktitle = {International Seminar on Computer Networking and Performance Evaluation}, keywords = {sys:hidden:inproceedings}, title = {Multiqueue Systems with Finite Capacity and Nonexhaustive Cyclic Service}, year = 1985 }

  %0 Conference Paper %1 info3-inproceedings-1985-176 %A Raith, Thomas %A Tran-Gia, Phuoc %B International Seminar on Computer Networking and Performance Evaluation %C Tokyo, Japan %D 1985 %T Multiqueue Systems with Finite Capacity and Nonexhaustive Cyclic Service

• Simulation of Instationary Processes for Performance Evaluations of Switching Systems. Tran-Gia, Phuoc. In 1st European Simulation Congress. Aachen, Germany, 1983.
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  @inproceedings{info3-inproceedings-1983-179, address = {Aachen, Germany}, author = {Tran-Gia, Phuoc}, booktitle = {1st European Simulation Congress}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Simulation of Instationary Processes for Performance Evaluations of Switching Systems}, year = 1983 }

  %0 Conference Paper %1 info3-inproceedings-1983-179 %A Tran-Gia, Phuoc %B 1st European Simulation Congress %C Aachen, Germany %D 1983 %T Simulation of Instationary Processes for Performance Evaluations of Switching Systems
• A Renewal Approximation for the Generalized Switched Poisson Process. Tran-Gia, Phuoc. In International Workshop on Applied Mathematics and Perfomance/ Reliability Models of Cumputer/communication Systems. Pisa, Italy, 1983.
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  @inproceedings{info3-inproceedings-1983-178, address = {Pisa, Italy}, author = {Tran-Gia, Phuoc}, booktitle = {International Workshop on Applied Mathematics and Perfomance/ Reliability Models of Cumputer/communication Systems}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {A Renewal Approximation for the Generalized Switched Poisson Process}, year = 1983 }

  %0 Conference Paper %1 info3-inproceedings-1983-178 %A Tran-Gia, Phuoc %B International Workshop on Applied Mathematics and Perfomance/ Reliability Models of Cumputer/communication Systems %C Pisa, Italy %D 1983 %T A Renewal Approximation for the Generalized Switched Poisson Process
• Queueing Analysis of an Arrival-driven Message Transfer Protocol. Manfield, David; Tran-Gia, Phuoc. In 10th International Teletraffic Congress. Montreal, Canada, 1983.
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  @inproceedings{info3-inproceedings-1983-180, address = {Montreal, Canada}, author = {Manfield, David and Tran-Gia, Phuoc}, booktitle = {10th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Queueing Analysis of an Arrival-driven Message Transfer Protocol}, year = 1983 }

  %0 Conference Paper %1 info3-inproceedings-1983-180 %A Manfield, David %A Tran-Gia, Phuoc %B 10th International Teletraffic Congress %C Montreal, Canada %D 1983 %T Queueing Analysis of an Arrival-driven Message Transfer Protocol
• Subcall-oriented Modelling of Overload Control in SPC Switching Systems. Tran-Gia, Phuoc. In 10th International Teletraffic Congress. Montreal, Canada, 1983.
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  @inproceedings{info3-inproceedings-1983-181, address = {Montreal, Canada}, author = {Tran-Gia, Phuoc}, booktitle = {10th International Teletraffic Congress}, keywords = {sys:hidden:inproceedings}, month = {06}, title = {Subcall-oriented Modelling of Overload Control in SPC Switching Systems}, year = 1983 }

  %0 Conference Paper %1 info3-inproceedings-1983-181 %A Tran-Gia, Phuoc %B 10th International Teletraffic Congress %C Montreal, Canada %D 1983 %T Subcall-oriented Modelling of Overload Control in SPC Switching Systems

• Clocked Event Transfer Protocol in Distributed Processing Systems - A Performance Analysis. Jans, Herbert; Tran-Gia, Phuoc. In ICCC. London, England, 1982.
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  @inproceedings{info3-inproceedings-1982-182, address = {London, England}, author = {Jans, Herbert and Tran-Gia, Phuoc}, booktitle = {ICCC}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Clocked Event Transfer Protocol in Distributed Processing Systems - A Performance Analysis}, year = 1982 }

  %0 Conference Paper %1 info3-inproceedings-1982-182 %A Jans, Herbert %A Tran-Gia, Phuoc %B ICCC %C London, England %D 1982 %T Clocked Event Transfer Protocol in Distributed Processing Systems - A Performance Analysis

• Queueing Analysis of Scheduled Communication Phases in Distributed Processing Systems. Manfield, David; Tran-Gia, Phuoc. In 8th Symp. on Comp. Perf. Modelling, Meas. and Eval., pp. 233–250. Amsterdam, Niederlande, 1981.
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  @inproceedings{info3-inproceedings-1981-183, address = {Amsterdam, Niederlande}, author = {Manfield, David and Tran-Gia, Phuoc}, booktitle = {8th Symp. on Comp. Perf. Modelling, Meas. and Eval.}, keywords = {sys:hidden:inproceedings}, month = 11, pages = {233-250}, title = {Queueing Analysis of Scheduled Communication Phases in Distributed Processing Systems}, year = 1981 }

  %0 Conference Paper %1 info3-inproceedings-1981-183 %A Manfield, David %A Tran-Gia, Phuoc %B 8th Symp. on Comp. Perf. Modelling, Meas. and Eval. %C Amsterdam, Niederlande %D 1981 %P 233-250 %T Queueing Analysis of Scheduled Communication Phases in Distributed Processing Systems
• Modelling and Analysis of Software Resources in Modular SPC-Switching Systems - Some Aspects of Dimensioning and Overload Control. Tran-Gia, Phuoc. In 4th Int. Conf. on Software Engineering for Telecommunication Switching Systems, pp. 172–176. Warwick, GB, 1981.
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  @inproceedings{info3-inproceedings-1981-184, address = {Warwick, GB}, author = {Tran-Gia, Phuoc}, booktitle = {4th Int. Conf. on Software Engineering for Telecommunication Switching Systems}, keywords = {sys:hidden:inproceedings}, month = {07}, pages = {172-176}, title = {Modelling and Analysis of Software Resources in Modular SPC-Switching Systems - Some Aspects of Dimensioning and Overload Control}, year = 1981 }

  %0 Conference Paper %1 info3-inproceedings-1981-184 %A Tran-Gia, Phuoc %B 4th Int. Conf. on Software Engineering for Telecommunication Switching Systems %C Warwick, GB %D 1981 %P 172-176 %T Modelling and Analysis of Software Resources in Modular SPC-Switching Systems - Some Aspects of Dimensioning and Overload Control