Prof. Dr. Thomas Zinner

• Discrete-Time Modeling of NFV Accelerators that Exploit Batched Processing Geissler, Stefan; Lange, Stanislav; Linguaglossa, Leonardo; Rossi, Dario; Zinner, Thomas; Hoßfeld, Tobias in ACM Transactions on Modeling and Performance Evaluation of Computing Systems (2021). 6(3) 1–27.
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  @article{info3-article-2021-12, author = {Geissler, Stefan and Lange, Stanislav and Linguaglossa, Leonardo and Rossi, Dario and Zinner, Thomas and Hoßfeld, Tobias}, journal = {ACM Transactions on Modeling and Performance Evaluation of Computing Systems}, keywords = {can}, month = 9, number = 3, pages = {1-27}, title = {Discrete-Time Modeling of NFV Accelerators that Exploit Batched Processing}, volume = 6, year = 2021 }

  %0 Journal Article %1 info3-article-2021-12 %A Geissler, Stefan %A Lange, Stanislav %A Linguaglossa, Leonardo %A Rossi, Dario %A Zinner, Thomas %A Hoßfeld, Tobias %D 2021 %J ACM Transactions on Modeling and Performance Evaluation of Computing Systems %N 3 %P 1-27 %T Discrete-Time Modeling of NFV Accelerators that Exploit Batched Processing %V 6
• Survey of Performance Acceleration Techniques for Network Function Virtualization Linguaglossa, Leonardo; Lange, Stanislav; Pontarelli, Salvatore; Retvari, Gabor; Rossi, Dario; Zinner, Thomas; Bificulo, Roberto; Jarschel, Michael; Bianchi, Giuseppe in Proceedings of the IEEE (2019).
  • [ Abstract ]
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  The ongoing network softwarization trend holds the promise to revolutionize network infrastructures by making them more flexible, reconfigurable, portable, and more adaptive than ever. Still, the migration from hard-coded/hardwired network functions towards their software-programmable counterparts comes along with the need for tailored optimizations and acceleration techniques, so as to avoid, or at least mitigate, the throughput/latency performance degradation with respect to fixed function network elements. The contribution of this article is twofold. First, we provide a comprehensive overview of the host-based Network Function Virtualization (NFV) ecosystem, covering a broad range of techniques, from low level hardware acceleration and bump-in-the-wire offloading approaches, to high-level software acceleration solutions, including the virtualization technique itself. Second, we derive guidelines regarding the design, development, and operation of NFV-based deployments that meet the flexibility and scalability requirements of modern communication networks.

  @article{info3-article-2019-1, abstract = {The ongoing network softwarization trend holds the promise to revolutionize network infrastructures by making them more flexible, reconfigurable, portable, and more adaptive than ever. Still, the migration from hard-coded/hardwired network functions towards their software-programmable counterparts comes along with the need for tailored optimizations and acceleration techniques, so as to avoid, or at least mitigate, the throughput/latency performance degradation with respect to fixed function network elements. The contribution of this article is twofold. First, we provide a comprehensive overview of the host-based Network Function Virtualization (NFV) ecosystem, covering a broad range of techniques, from low level hardware acceleration and bump-in-the-wire offloading approaches, to high-level software acceleration solutions, including the virtualization technique itself. Second, we derive guidelines regarding the design, development, and operation of NFV-based deployments that meet the flexibility and scalability requirements of modern communication networks.}, author = {Linguaglossa, Leonardo and Lange, Stanislav and Pontarelli, Salvatore and Retvari, Gabor and Rossi, Dario and Zinner, Thomas and Bificulo, Roberto and Jarschel, Michael and Bianchi, Giuseppe}, journal = {Proceedings of the IEEE}, keywords = {sys:hidden:article}, month = 1, title = {Survey of Performance Acceleration Techniques for Network Function Virtualization}, year = 2019 }

  %0 Journal Article %1 info3-article-2019-1 %A Linguaglossa, Leonardo %A Lange, Stanislav %A Pontarelli, Salvatore %A Retvari, Gabor %A Rossi, Dario %A Zinner, Thomas %A Bificulo, Roberto %A Jarschel, Michael %A Bianchi, Giuseppe %D 2019 %J Proceedings of the IEEE %T Survey of Performance Acceleration Techniques for Network Function Virtualization %X The ongoing network softwarization trend holds the promise to revolutionize network infrastructures by making them more flexible, reconfigurable, portable, and more adaptive than ever. Still, the migration from hard-coded/hardwired network functions towards their software-programmable counterparts comes along with the need for tailored optimizations and acceleration techniques, so as to avoid, or at least mitigate, the throughput/latency performance degradation with respect to fixed function network elements. The contribution of this article is twofold. First, we provide a comprehensive overview of the host-based Network Function Virtualization (NFV) ecosystem, covering a broad range of techniques, from low level hardware acceleration and bump-in-the-wire offloading approaches, to high-level software acceleration solutions, including the virtualization technique itself. Second, we derive guidelines regarding the design, development, and operation of NFV-based deployments that meet the flexibility and scalability requirements of modern communication networks.
• The Power of Composition: Abstracting a Multi-Device SDN Data Path Through a Single API Geissler, Stefan; Herrnleben, Stefan; Bauer, Robert; Grigorjew, Alexej; Jarschel, Michael; Zinner, Thomas in IEEE Transactions on Network and Service Management (2019).
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  @article{info3-article-2019-11, author = {Geissler, Stefan and Herrnleben, Stefan and Bauer, Robert and Grigorjew, Alexej and Jarschel, Michael and Zinner, Thomas}, journal = {IEEE Transactions on Network and Service Management}, keywords = {sys:hidden:article}, month = 11, title = {The Power of Composition: Abstracting a Multi-Device SDN Data Path Through a Single API}, year = 2019 }

  %0 Journal Article %1 info3-article-2019-11 %A Geissler, Stefan %A Herrnleben, Stefan %A Bauer, Robert %A Grigorjew, Alexej %A Jarschel, Michael %A Zinner, Thomas %D 2019 %J IEEE Transactions on Network and Service Management %T The Power of Composition: Abstracting a Multi-Device SDN Data Path Through a Single API
• A Generic Approach to Video Buffer Modeling using Discrete-Time Analysis Burger, Valentin; Zinner, Thomas; Dinh-Xuan, Lam; Wamser, Florian; Tran-Gia, Phuoc in ACM Transactions on Multimedia Computing, Communications, and Applications (TOMM) (2018). 14(33) 23.
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  @article{info3-article-2018-1, author = {Burger, Valentin and Zinner, Thomas and Dinh-Xuan, Lam and Wamser, Florian and Tran-Gia, Phuoc}, journal = {ACM Transactions on Multimedia Computing, Communications, and Applications (TOMM)}, keywords = {sys:hidden:article}, month = 4, number = 33, pages = 23, title = {A Generic Approach to Video Buffer Modeling using Discrete-Time Analysis}, volume = 14, year = 2018 }

  %0 Journal Article %1 info3-article-2018-1 %A Burger, Valentin %A Zinner, Thomas %A Dinh-Xuan, Lam %A Wamser, Florian %A Tran-Gia, Phuoc %D 2018 %J ACM Transactions on Multimedia Computing, Communications, and Applications (TOMM) %N 33 %P 23 %T A Generic Approach to Video Buffer Modeling using Discrete-Time Analysis %V 14
• An SDN/NFV-enabled Enterprise Network Architecture Offering Fine-Grained Security Policy Enforcement Lorenz, Claas; Hock, David; Scherer, Johann; Durner, Raphael; Kellerer, Wolfgang; Gebert, Steffen; Gray, Nicholas; Zinner, Thomas; Tran-Gia, Phuoc in IEEE Communications Magazine (2017). 55(3) 217–223.
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  In recent years, the number of attacks and threat vectors against enterprise networks have been constantly increasing in numbers and variety. In addition, new challenges arise not only to the level of provided security, but also to the scalability and manageability of the deployed countermeasures such as firewalls and intrusion detection systems. Despite these attacks, the main security systems, e.g., network firewalls, have remained rather unchanged. Due to the tight integration into the physical network’s infrastructure, a dynamic resource allocation to adapt the security measures to the current network conditions is a difficult undertaking. Therefore, in this work, we analyze and compare different architectural design patterns for the integration of SDN/NFV-based security solutions into enterprise networks.

  @article{info3-article-2016-9, abstract = {In recent years, the number of attacks and threat vectors against enterprise networks have been constantly increasing in numbers and variety. In addition, new challenges arise not only to the level of provided security, but also to the scalability and manageability of the deployed countermeasures such as firewalls and intrusion detection systems. Despite these attacks, the main security systems, e.g., network firewalls, have remained rather unchanged. Due to the tight integration into the physical network’s infrastructure, a dynamic resource allocation to adapt the security measures to the current network conditions is a difficult undertaking. Therefore, in this work, we analyze and compare different architectural design patterns for the integration of SDN/NFV-based security solutions into enterprise networks.}, author = {Lorenz, Claas and Hock, David and Scherer, Johann and Durner, Raphael and Kellerer, Wolfgang and Gebert, Steffen and Gray, Nicholas and Zinner, Thomas and Tran-Gia, Phuoc}, journal = {IEEE Communications Magazine}, keywords = {sys:hidden:article}, month = 3, number = 3, pages = {217 - 223}, title = {An SDN/NFV-enabled Enterprise Network Architecture Offering Fine-Grained Security Policy Enforcement}, volume = 55, year = 2017 }

  %0 Journal Article %1 info3-article-2016-9 %A Lorenz, Claas %A Hock, David %A Scherer, Johann %A Durner, Raphael %A Kellerer, Wolfgang %A Gebert, Steffen %A Gray, Nicholas %A Zinner, Thomas %A Tran-Gia, Phuoc %D 2017 %J IEEE Communications Magazine %N 3 %P 217 - 223 %T An SDN/NFV-enabled Enterprise Network Architecture Offering Fine-Grained Security Policy Enforcement %V 55 %X In recent years, the number of attacks and threat vectors against enterprise networks have been constantly increasing in numbers and variety. In addition, new challenges arise not only to the level of provided security, but also to the scalability and manageability of the deployed countermeasures such as firewalls and intrusion detection systems. Despite these attacks, the main security systems, e.g., network firewalls, have remained rather unchanged. Due to the tight integration into the physical network’s infrastructure, a dynamic resource allocation to adapt the security measures to the current network conditions is a difficult undertaking. Therefore, in this work, we analyze and compare different architectural design patterns for the integration of SDN/NFV-based security solutions into enterprise networks.
• A Discrete-Time Model for Optimizing the Processing Time of Virtualized Network Functions Zinner, Thomas; Geissler, Stefan; Lange, Stanislav; Gebert, Steffen; Seufert, Michael; Tran-Gia, Phuoc in Computer Networks (2017). 125 4–14.
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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 of adjustment and tuning, which can affect performance and resource utilization. One of these adjustments are interrupt moderation techniques implemented by modern network interface cards and operating systems. Using these, an administrator can optimize either for low latencies or low CPU overhead for processing of network traffic. In this work, an analytical model that allows the computation of relevant performance metrics like packet processing time and packet loss for generic virtualized network functions running on commodity hardware is presented. Based on this model, impact factors like average packet interarrival time, interarrival time distribution, and duration of the interrupt aggregation interval are studied. Furthermore, we significantly improve the computational tractability of this discrete-time model by proving and leveraging a property regarding its limit behavior. We also demonstrate that using this property does not affect the accuracy of the model in the context of realistic parameter combinations. Finally, the improved runtime for numerical evaluations allows administrators to dynamically adapt their interrupt mitigation settings to changing network conditions by recalculating optimal parameters.

  @article{info3-article-2017-1, 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 of adjustment and tuning, which can affect performance and resource utilization. One of these adjustments are interrupt moderation techniques implemented by modern network interface cards and operating systems. Using these, an administrator can optimize either for low latencies or low CPU overhead for processing of network traffic. In this work, an analytical model that allows the computation of relevant performance metrics like packet processing time and packet loss for generic virtualized network functions running on commodity hardware is presented. Based on this model, impact factors like average packet interarrival time, interarrival time distribution, and duration of the interrupt aggregation interval are studied. Furthermore, we significantly improve the computational tractability of this discrete-time model by proving and leveraging a property regarding its limit behavior. We also demonstrate that using this property does not affect the accuracy of the model in the context of realistic parameter combinations. Finally, the improved runtime for numerical evaluations allows administrators to dynamically adapt their interrupt mitigation settings to changing network conditions by recalculating optimal parameters.}, author = {Zinner, Thomas and Geissler, Stefan and Lange, Stanislav and Gebert, Steffen and Seufert, Michael and Tran-Gia, Phuoc}, journal = {Computer Networks}, keywords = {sys:hidden:article}, pages = {4-14}, title = {A Discrete-Time Model for Optimizing the Processing Time of Virtualized Network Functions}, volume = 125, year = 2017 }

  %0 Journal Article %1 info3-article-2017-1 %A Zinner, Thomas %A Geissler, Stefan %A Lange, Stanislav %A Gebert, Steffen %A Seufert, Michael %A Tran-Gia, Phuoc %D 2017 %J Computer Networks %P 4-14 %T A Discrete-Time Model for Optimizing the Processing Time of Virtualized Network Functions %V 125 %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 of adjustment and tuning, which can affect performance and resource utilization. One of these adjustments are interrupt moderation techniques implemented by modern network interface cards and operating systems. Using these, an administrator can optimize either for low latencies or low CPU overhead for processing of network traffic. In this work, an analytical model that allows the computation of relevant performance metrics like packet processing time and packet loss for generic virtualized network functions running on commodity hardware is presented. Based on this model, impact factors like average packet interarrival time, interarrival time distribution, and duration of the interrupt aggregation interval are studied. Furthermore, we significantly improve the computational tractability of this discrete-time model by proving and leveraging a property regarding its limit behavior. We also demonstrate that using this property does not affect the accuracy of the model in the context of realistic parameter combinations. Finally, the improved runtime for numerical evaluations allows administrators to dynamically adapt their interrupt mitigation settings to changing network conditions by recalculating optimal parameters.
• Design and Performance Evaluation of Network-assisted Control Strategies for HTTP Adaptive Streaming Cofano, Giuseppe; De Cicco, Luca; Zinner, Thomas; Nguyen-Ngoc, Anh; Tran-Gia, Phuoc; Mascolo, Saverio in ACM Transactions on Multimedia Computing, Communications, and Applications (2017).
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  @article{info3-article-2017-2, author = {Cofano, Giuseppe and De Cicco, Luca and Zinner, Thomas and Nguyen-Ngoc, Anh and Tran-Gia, Phuoc and Mascolo, Saverio}, journal = {ACM Transactions on Multimedia Computing, Communications, and Applications}, keywords = {sys:hidden:article}, title = {Design and Performance Evaluation of Network-assisted Control Strategies for HTTP Adaptive Streaming}, year = 2017 }

  %0 Journal Article %1 info3-article-2017-2 %A Cofano, Giuseppe %A De Cicco, Luca %A Zinner, Thomas %A Nguyen-Ngoc, Anh %A Tran-Gia, Phuoc %A Mascolo, Saverio %D 2017 %J ACM Transactions on Multimedia Computing, Communications, and Applications %T Design and Performance Evaluation of Network-assisted Control Strategies for HTTP Adaptive Streaming
• Quantitative Comparison of Application-Network Interaction: A Case Study of Adaptive Video Streaming Schwarzmann, Susanna; Zinner, Thomas; Dobrijevic, Ognjen in Springer Quality and User Experience (2017).
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  Managing quality of experience (QoE) is now widely accepted as a critical objective for multimedia applications and the supporting communication systems. In general, QoE management encompasses: (i) monitoring of the key influence factors and QoE indicators, and (ii) deciding on the appropriate control actions as specified by the management goal. Many multimedia applications, e.g. video streaming and audio conferencing, are able to adjust their operational parameters so as to react to variations in the network performance. However, such an adaptation feature is mostly based on a local client view of the network conditions, which may lead to an unfair allocation of network resources among heterogeneous clients and, thus, an unfair QoE distribution. In order to tackle this issue, there is the call for a cooperation between the applications and the underlying network, which includes application-network interaction (App-Net) in terms of: (1) exchanging information on the monitored QoE indicators, and (2) coordinating the QoE control actions. Various App-Net mechanisms focusing on specific use cases and applications have been proposed to date. This paper gives an overview of App-Net mechanisms and proposes a generic App-Net model that provides the means to realize a coordinated QoE-centric management. Based on the App-Net model, we develop an evaluation methodology to compare three App-Net mechanisms for managing QoE of HTTP adaptive streaming (HAS) against a baseline HAS service. The aim of this quantitative comparison is to explore the trade-offs between QoE gains and the complexity of App-Net implementation, with respect to the number of monitoring and control messages, achieved video quality, and QoE fairness among heterogeneous clients. Our ultimate goal is to set up reproducible experiments that facilitate a holistic evaluation of different App-Net mechanisms.

  @article{info3-article-2017-4, abstract = {Managing quality of experience (QoE) is now widely accepted as a critical objective for multimedia applications and the supporting communication systems. In general, QoE management encompasses: (i) monitoring of the key influence factors and QoE indicators, and (ii) deciding on the appropriate control actions as specified by the management goal. Many multimedia applications, e.g. video streaming and audio conferencing, are able to adjust their operational parameters so as to react to variations in the network performance. However, such an adaptation feature is mostly based on a local client view of the network conditions, which may lead to an unfair allocation of network resources among heterogeneous clients and, thus, an unfair QoE distribution. In order to tackle this issue, there is the call for a cooperation between the applications and the underlying network, which includes application-network interaction (App-Net) in terms of: (1) exchanging information on the monitored QoE indicators, and (2) coordinating the QoE control actions. Various App-Net mechanisms focusing on specific use cases and applications have been proposed to date. This paper gives an overview of App-Net mechanisms and proposes a generic App-Net model that provides the means to realize a coordinated QoE-centric management. Based on the App-Net model, we develop an evaluation methodology to compare three App-Net mechanisms for managing QoE of HTTP adaptive streaming (HAS) against a baseline HAS service. The aim of this quantitative comparison is to explore the trade-offs between QoE gains and the complexity of App-Net implementation, with respect to the number of monitoring and control messages, achieved video quality, and QoE fairness among heterogeneous clients. Our ultimate goal is to set up reproducible experiments that facilitate a holistic evaluation of different App-Net mechanisms.}, author = {Schwarzmann, Susanna and Zinner, Thomas and Dobrijevic, Ognjen}, journal = {Springer Quality and User Experience}, keywords = {sys:hidden:article}, title = {Quantitative Comparison of Application-Network Interaction: A Case Study of Adaptive Video Streaming}, year = 2017 }

  %0 Journal Article %1 info3-article-2017-4 %A Schwarzmann, Susanna %A Zinner, Thomas %A Dobrijevic, Ognjen %D 2017 %J Springer Quality and User Experience %T Quantitative Comparison of Application-Network Interaction: A Case Study of Adaptive Video Streaming %X Managing quality of experience (QoE) is now widely accepted as a critical objective for multimedia applications and the supporting communication systems. In general, QoE management encompasses: (i) monitoring of the key influence factors and QoE indicators, and (ii) deciding on the appropriate control actions as specified by the management goal. Many multimedia applications, e.g. video streaming and audio conferencing, are able to adjust their operational parameters so as to react to variations in the network performance. However, such an adaptation feature is mostly based on a local client view of the network conditions, which may lead to an unfair allocation of network resources among heterogeneous clients and, thus, an unfair QoE distribution. In order to tackle this issue, there is the call for a cooperation between the applications and the underlying network, which includes application-network interaction (App-Net) in terms of: (1) exchanging information on the monitored QoE indicators, and (2) coordinating the QoE control actions. Various App-Net mechanisms focusing on specific use cases and applications have been proposed to date. This paper gives an overview of App-Net mechanisms and proposes a generic App-Net model that provides the means to realize a coordinated QoE-centric management. Based on the App-Net model, we develop an evaluation methodology to compare three App-Net mechanisms for managing QoE of HTTP adaptive streaming (HAS) against a baseline HAS service. The aim of this quantitative comparison is to explore the trade-offs between QoE gains and the complexity of App-Net implementation, with respect to the number of monitoring and control messages, achieved video quality, and QoE fairness among heterogeneous clients. Our ultimate goal is to set up reproducible experiments that facilitate a holistic evaluation of different App-Net mechanisms.
• Analytical Model for SDN Signaling Traffic and Flow Table Occupancy and its Application for Various Types of Traffic Metter, Christopher; Seufert, Michael; Wamser, Florian; Zinner, Thomas; Tran-Gia, Phuoc in IEEE Transactions on Network and Service Management (2017). 14(3) 603–615.
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  Software Defined Networking (SDN) has emerged as a promising networking paradigm overcoming various drawbacks of current communication networks. The control and data plane of switching devices is decoupled and control functions are centralized at the network controller. In SDN, each new flow introduces additional signaling traffic between the switch and the controller. Based on this traffic, rules are created in the flow table of the switch, which specify the forwarding behavior. To avoid table overflows, unused entries are removed after a predefined time-out period. Given a specific traffic mix, the choice of this time-out period affects the trade-off between signaling rate and table occupancy. As a result, network operators have to adjust this parameter to enable a smooth and efficient network operation. Due to the complexity of this problem caused by the various traffic flows in a network, a suitable abstraction is necessary in order to derive valid parameter values in time. The contribution of this work is threefold. Firstly, we formulate a simple analytical model that allows optimizing the network performance with respect to the table occupancy and the signaling rate. Secondly, we validate the model by means of simulation. Thirdly, we illustrate the impact of the time-out period on the signaling traffic and the flow table occupancy for different data-plane traffic mixes and characteristics. This includes scenarios with single application instances, as well as multiple application instances of different application types in an SDN-enabled network.

  @article{info3-article-2017-5, abstract = {Software Defined Networking (SDN) has emerged as a promising networking paradigm overcoming various drawbacks of current communication networks. The control and data plane of switching devices is decoupled and control functions are centralized at the network controller. In SDN, each new flow introduces additional signaling traffic between the switch and the controller. Based on this traffic, rules are created in the flow table of the switch, which specify the forwarding behavior. To avoid table overflows, unused entries are removed after a predefined time-out period. Given a specific traffic mix, the choice of this time-out period affects the trade-off between signaling rate and table occupancy. As a result, network operators have to adjust this parameter to enable a smooth and efficient network operation. Due to the complexity of this problem caused by the various traffic flows in a network, a suitable abstraction is necessary in order to derive valid parameter values in time. The contribution of this work is threefold. Firstly, we formulate a simple analytical model that allows optimizing the network performance with respect to the table occupancy and the signaling rate. Secondly, we validate the model by means of simulation. Thirdly, we illustrate the impact of the time-out period on the signaling traffic and the flow table occupancy for different data-plane traffic mixes and characteristics. This includes scenarios with single application instances, as well as multiple application instances of different application types in an SDN-enabled network.}, author = {Metter, Christopher and Seufert, Michael and Wamser, Florian and Zinner, Thomas and Tran-Gia, Phuoc}, journal = {IEEE Transactions on Network and Service Management}, keywords = {can}, month = 9, number = 3, pages = {603-615}, title = {Analytical Model for SDN Signaling Traffic and Flow Table Occupancy and its Application for Various Types of Traffic}, volume = 14, year = 2017 }

  %0 Journal Article %1 info3-article-2017-5 %A Metter, Christopher %A Seufert, Michael %A Wamser, Florian %A Zinner, Thomas %A Tran-Gia, Phuoc %D 2017 %J IEEE Transactions on Network and Service Management %N 3 %P 603-615 %T Analytical Model for SDN Signaling Traffic and Flow Table Occupancy and its Application for Various Types of Traffic %V 14 %X Software Defined Networking (SDN) has emerged as a promising networking paradigm overcoming various drawbacks of current communication networks. The control and data plane of switching devices is decoupled and control functions are centralized at the network controller. In SDN, each new flow introduces additional signaling traffic between the switch and the controller. Based on this traffic, rules are created in the flow table of the switch, which specify the forwarding behavior. To avoid table overflows, unused entries are removed after a predefined time-out period. Given a specific traffic mix, the choice of this time-out period affects the trade-off between signaling rate and table occupancy. As a result, network operators have to adjust this parameter to enable a smooth and efficient network operation. Due to the complexity of this problem caused by the various traffic flows in a network, a suitable abstraction is necessary in order to derive valid parameter values in time. The contribution of this work is threefold. Firstly, we formulate a simple analytical model that allows optimizing the network performance with respect to the table occupancy and the signaling rate. Secondly, we validate the model by means of simulation. Thirdly, we illustrate the impact of the time-out period on the signaling traffic and the flow table occupancy for different data-plane traffic mixes and characteristics. This includes scenarios with single application instances, as well as multiple application instances of different application types in an SDN-enabled network.
• SDN and NFV as Enabler for the Distributed Network Cloud Hoffmann, Marco; Jarschel, Michael; Pries, Rastin; Schneider, Peter; Jukan, Admela; Bziuk, Wolfgang; Gebert, Steffen; Zinner, Thomas; Tran-Gia, Phuoc in Mobile Networks and Applications (2017).
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  @article{info3-article-2017-8, author = {Hoffmann, Marco and Jarschel, Michael and Pries, Rastin and Schneider, Peter and Jukan, Admela and Bziuk, Wolfgang and Gebert, Steffen and Zinner, Thomas and Tran-Gia, Phuoc}, journal = {Mobile Networks and Applications}, keywords = {sys:hidden:article}, title = {SDN and NFV as Enabler for the Distributed Network Cloud}, year = 2017 }

  %0 Journal Article %1 info3-article-2017-8 %A Hoffmann, Marco %A Jarschel, Michael %A Pries, Rastin %A Schneider, Peter %A Jukan, Admela %A Bziuk, Wolfgang %A Gebert, Steffen %A Zinner, Thomas %A Tran-Gia, Phuoc %D 2017 %J Mobile Networks and Applications %T SDN and NFV as Enabler for the Distributed Network Cloud
• Modeling and Performance Analysis of Application-Aware Resource Management Wamser, Florian; Blenk, Andreas; Seufert, Michael; Zinner, Thomas; Kellerer, Wolfgang; Tran-Gia, Phuoc in International Journal of Network Management (2015). 25 223–241.
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  Application-aware resource management is the approach to tailor access networks to have characteristics beneficial for the running applications and services. This is achieved through the monitoring and integration of key performance indicators from the application layer within the network resource management. The aim is to increase user-perceived quality and network resource efficiency by traffic engineering with the help of these indicators. Using analytic and simulative approaches, this paper provides analysis methods for network operators to quantify the performance gains of alternative resource allocation algorithms that implement the application-aware concept. Network operators can use the proposed methods to evaluate possible performance gain trade-offs between investing in a pure capacity increase (over-provisioning) and the realization of an application-aware resource allocation. For this purpose, we model and analyze the application quality trade-offs of four algorithms for application-aware resource management at a single link in varying traffic situations. The algorithms are chosen with respect to different complexity and implementation level in order to cover the design space in a systematic way. The study of the algorithms focuses on the application-layer performance for the most used applications today, namely web browsing and video streaming with constant bit-rate as well as HTTP progressive streaming with variable bit-rate. Application quality trade-offs are analyzed in particular for a high resource utilization at a bottleneck link. The results confirm that application-aware resource management outperforms best-effort resource management in terms of QoE. Moreover, our study provides guidelines for the selection and configuration of the evaluated algorithms.

  @article{info3-article-2015-134, abstract = {Application-aware resource management is the approach to tailor access networks to have characteristics beneficial for the running applications and services. This is achieved through the monitoring and integration of key performance indicators from the application layer within the network resource management. The aim is to increase user-perceived quality and network resource efficiency by traffic engineering with the help of these indicators. Using analytic and simulative approaches, this paper provides analysis methods for network operators to quantify the performance gains of alternative resource allocation algorithms that implement the application-aware concept. Network operators can use the proposed methods to evaluate possible performance gain trade-offs between investing in a pure capacity increase (over-provisioning) and the realization of an application-aware resource allocation. For this purpose, we model and analyze the application quality trade-offs of four algorithms for application-aware resource management at a single link in varying traffic situations. The algorithms are chosen with respect to different complexity and implementation level in order to cover the design space in a systematic way. The study of the algorithms focuses on the application-layer performance for the most used applications today, namely web browsing and video streaming with constant bit-rate as well as HTTP progressive streaming with variable bit-rate. Application quality trade-offs are analyzed in particular for a high resource utilization at a bottleneck link. The results confirm that application-aware resource management outperforms best-effort resource management in terms of QoE. Moreover, our study provides guidelines for the selection and configuration of the evaluated algorithms.}, author = {Wamser, Florian and Blenk, Andreas and Seufert, Michael and Zinner, Thomas and Kellerer, Wolfgang and Tran-Gia, Phuoc}, journal = {International Journal of Network Management}, keywords = {sys:hidden:article}, month = 7, pages = {223-241}, title = {Modeling and Performance Analysis of Application-Aware Resource Management}, volume = 25, year = 2015 }

  %0 Journal Article %1 info3-article-2015-134 %A Wamser, Florian %A Blenk, Andreas %A Seufert, Michael %A Zinner, Thomas %A Kellerer, Wolfgang %A Tran-Gia, Phuoc %D 2015 %J International Journal of Network Management %P 223-241 %T Modeling and Performance Analysis of Application-Aware Resource Management %V 25 %X Application-aware resource management is the approach to tailor access networks to have characteristics beneficial for the running applications and services. This is achieved through the monitoring and integration of key performance indicators from the application layer within the network resource management. The aim is to increase user-perceived quality and network resource efficiency by traffic engineering with the help of these indicators. Using analytic and simulative approaches, this paper provides analysis methods for network operators to quantify the performance gains of alternative resource allocation algorithms that implement the application-aware concept. Network operators can use the proposed methods to evaluate possible performance gain trade-offs between investing in a pure capacity increase (over-provisioning) and the realization of an application-aware resource allocation. For this purpose, we model and analyze the application quality trade-offs of four algorithms for application-aware resource management at a single link in varying traffic situations. The algorithms are chosen with respect to different complexity and implementation level in order to cover the design space in a systematic way. The study of the algorithms focuses on the application-layer performance for the most used applications today, namely web browsing and video streaming with constant bit-rate as well as HTTP progressive streaming with variable bit-rate. Application quality trade-offs are analyzed in particular for a high resource utilization at a bottleneck link. The results confirm that application-aware resource management outperforms best-effort resource management in terms of QoE. Moreover, our study provides guidelines for the selection and configuration of the evaluated algorithms.
• Network Functions Virtualization (NFV) und Software Defined Networking (SDN): Forschungsfragen und Anwendungsfälle Blenk, Andreas; Basta, Arsany; Kellerer, Wolfgang; Zinner, Thomas; Wamser, Florian; Tran-Gia, Phuoc in ITG Mitgliederbeiträge / VDE dialog (invited article) (2015). 10–13.
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  @article{info3-article-2015-8, author = {Blenk, Andreas and Basta, Arsany and Kellerer, Wolfgang and Zinner, Thomas and Wamser, Florian and Tran-Gia, Phuoc}, journal = {ITG Mitgliederbeiträge / VDE dialog (invited article)}, keywords = {sys:hidden:article}, month = 1, pages = {10-13}, title = {Network Functions Virtualization (NFV) und Software Defined Networking (SDN): Forschungsfragen und Anwendungsfälle}, year = 2015 }

  %0 Journal Article %1 info3-article-2015-8 %A Blenk, Andreas %A Basta, Arsany %A Kellerer, Wolfgang %A Zinner, Thomas %A Wamser, Florian %A Tran-Gia, Phuoc %D 2015 %J ITG Mitgliederbeiträge / VDE dialog (invited article) %P 10-13 %T Network Functions Virtualization (NFV) und Software Defined Networking (SDN): Forschungsfragen und Anwendungsfälle
• A Survey on Quality of Experience of HTTP Adaptive Streaming Seufert, Michael; Egger, Sebastian; Slanina, Martin; Zinner, Thomas; Hoßfeld, Tobias; Tran-Gia, Phuoc in IEEE Communications Surveys & Tutorials (2015). 17 469–492.
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  Changing network conditions pose severe problems to video streaming in the Internet. HTTP adaptive streaming (HAS) is a technology employed by numerous video services which relieves these issues by adapting the video to the current network conditions. It enables service providers to improve resource utilization and Quality of Experience (QoE) by incorporating information from different layers in order to deliver and adapt a video in its best possible quality. Thereby, it allows to take into account end user device capabilities, available video quality levels, current network conditions, and current server load. For end users, the major benefits of HAS compared to classical HTTP video streaming are reduced interruptions of the video playback and higher bandwidth utilization, which both generally result in a higher QoE. Adaptation is possible by changing the frame rate, resolution, or quantization of the video, which can be done with various adaptation strategies and related client- and server-side actions. The technical development of HAS, existing open standardized solutions, but also proprietary solutions are reviewed in this article as fundament to derive the QoE influence factors which emerge as a result of adaptation. The main contribution is a comprehensive survey of QoE related works from human computer interaction and networking domains which are structured according to the QoE impact of video adaptation. To be more precise, subjective studies which cover QoE aspects of adaptation dimensions and strategies are revisited. As a result, QoE influence factors of HAS and corresponding QoE models are identified, but also open issues and conflicting results are discussed. Furthermore, technical influence factors, which are often ignored in the context of HAS, affect perceptual QoE influence factors and are consequently analyzed. This survey gives the reader an overview of the current state of the art and recent developments. At the same time it targets networking researchers who develop new solutions for HTTP video streaming or assess video streaming from a user centric point of view. Therefore, the article is a major step towards truly improving HAS.

  @article{info3-article-2015-126, abstract = {Changing network conditions pose severe problems to video streaming in the Internet. HTTP adaptive streaming (HAS) is a technology employed by numerous video services which relieves these issues by adapting the video to the current network conditions. It enables service providers to improve resource utilization and Quality of Experience (QoE) by incorporating information from different layers in order to deliver and adapt a video in its best possible quality. Thereby, it allows to take into account end user device capabilities, available video quality levels, current network conditions, and current server load. For end users, the major benefits of HAS compared to classical HTTP video streaming are reduced interruptions of the video playback and higher bandwidth utilization, which both generally result in a higher QoE. Adaptation is possible by changing the frame rate, resolution, or quantization of the video, which can be done with various adaptation strategies and related client- and server-side actions. The technical development of HAS, existing open standardized solutions, but also proprietary solutions are reviewed in this article as fundament to derive the QoE influence factors which emerge as a result of adaptation. The main contribution is a comprehensive survey of QoE related works from human computer interaction and networking domains which are structured according to the QoE impact of video adaptation. To be more precise, subjective studies which cover QoE aspects of adaptation dimensions and strategies are revisited. As a result, QoE influence factors of HAS and corresponding QoE models are identified, but also open issues and conflicting results are discussed. Furthermore, technical influence factors, which are often ignored in the context of HAS, affect perceptual QoE influence factors and are consequently analyzed. This survey gives the reader an overview of the current state of the art and recent developments. At the same time it targets networking researchers who develop new solutions for HTTP video streaming or assess video streaming from a user centric point of view. Therefore, the article is a major step towards truly improving HAS.}, author = {Seufert, Michael and Egger, Sebastian and Slanina, Martin and Zinner, Thomas and Hoßfeld, Tobias and Tran-Gia, Phuoc}, journal = {IEEE Communications Surveys & Tutorials}, keywords = {sys:hidden:article}, month = 3, pages = {469-492}, title = {A Survey on Quality of Experience of HTTP Adaptive Streaming}, volume = 17, year = 2015 }

  %0 Journal Article %1 info3-article-2015-126 %A Seufert, Michael %A Egger, Sebastian %A Slanina, Martin %A Zinner, Thomas %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %D 2015 %J IEEE Communications Surveys & Tutorials %P 469-492 %T A Survey on Quality of Experience of HTTP Adaptive Streaming %V 17 %X Changing network conditions pose severe problems to video streaming in the Internet. HTTP adaptive streaming (HAS) is a technology employed by numerous video services which relieves these issues by adapting the video to the current network conditions. It enables service providers to improve resource utilization and Quality of Experience (QoE) by incorporating information from different layers in order to deliver and adapt a video in its best possible quality. Thereby, it allows to take into account end user device capabilities, available video quality levels, current network conditions, and current server load. For end users, the major benefits of HAS compared to classical HTTP video streaming are reduced interruptions of the video playback and higher bandwidth utilization, which both generally result in a higher QoE. Adaptation is possible by changing the frame rate, resolution, or quantization of the video, which can be done with various adaptation strategies and related client- and server-side actions. The technical development of HAS, existing open standardized solutions, but also proprietary solutions are reviewed in this article as fundament to derive the QoE influence factors which emerge as a result of adaptation. The main contribution is a comprehensive survey of QoE related works from human computer interaction and networking domains which are structured according to the QoE impact of video adaptation. To be more precise, subjective studies which cover QoE aspects of adaptation dimensions and strategies are revisited. As a result, QoE influence factors of HAS and corresponding QoE models are identified, but also open issues and conflicting results are discussed. Furthermore, technical influence factors, which are often ignored in the context of HAS, affect perceptual QoE influence factors and are consequently analyzed. This survey gives the reader an overview of the current state of the art and recent developments. At the same time it targets networking researchers who develop new solutions for HTTP video streaming or assess video streaming from a user centric point of view. Therefore, the article is a major step towards truly improving HAS.
• Heuristic Approaches to the Controller Placement Problem in Large Scale SDN Networks Lange, Stanislav; Gebert, Steffen; Zinner, Thomas; Tran-Gia, Phuoc; Hock, David; Jarschel, Michael; Hoffmann, Marco in IEEE Transactions on Network and Service Management - Special Issue on Efficient Management of SDN and NFV-based Systems (2015). 12(1) 4–17.
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  Software Defined Networking (SDN) marks a paradigm shift towards an externalized and logically centralized network control plane. A particularly important task in SDN architectures is that of controller placement, i.e., the positioning of a limited number of resources within a network in order to meet various requirements. These requirements range from latency constraints to failure tolerance and load balancing. In most scenarios, at least some of these objectives are competing, thus no single best placement is available and decision makers need to find a balanced trade-off. This work presents POCO, a framework for Pareto-based Optimal COntroller placement that provides operators with Pareto optimal placements with respect to different performance metrics. In its default configuration, POCO performs an exhaustive evaluation of all possible placements. While this is practically feasible for small and medium sized networks, realistic time and resource constraints call for an alternative in the context of large scale networks or dynamic networks whose properties change over time. For these scenarios, the POCO toolset is extended by a heuristic approach that is less accurate, but yields faster computation times. An evaluation of this heuristic is performed on a collection of real world network topologies from the Internet Topology Zoo. Utilizing a measure for quantifying the error introduced by the heuristic approach allows an analysis of the resulting trade-off between time and accuracy. Additionally, the proposed methods can be extended to solve similar virtual functions placement problems which appear in the context of Network Functions Virtualization (NFV).

  @article{info3-article-2015-131, abstract = {Software Defined Networking (SDN) marks a paradigm shift towards an externalized and logically centralized network control plane. A particularly important task in SDN architectures is that of controller placement, i.e., the positioning of a limited number of resources within a network in order to meet various requirements. These requirements range from latency constraints to failure tolerance and load balancing. In most scenarios, at least some of these objectives are competing, thus no single best placement is available and decision makers need to find a balanced trade-off. This work presents POCO, a framework for Pareto-based Optimal COntroller placement that provides operators with Pareto optimal placements with respect to different performance metrics. In its default configuration, POCO performs an exhaustive evaluation of all possible placements. While this is practically feasible for small and medium sized networks, realistic time and resource constraints call for an alternative in the context of large scale networks or dynamic networks whose properties change over time. For these scenarios, the POCO toolset is extended by a heuristic approach that is less accurate, but yields faster computation times. An evaluation of this heuristic is performed on a collection of real world network topologies from the Internet Topology Zoo. Utilizing a measure for quantifying the error introduced by the heuristic approach allows an analysis of the resulting trade-off between time and accuracy. Additionally, the proposed methods can be extended to solve similar virtual functions placement problems which appear in the context of Network Functions Virtualization (NFV).}, author = {Lange, Stanislav and Gebert, Steffen and Zinner, Thomas and Tran-Gia, Phuoc and Hock, David and Jarschel, Michael and Hoffmann, Marco}, journal = {IEEE Transactions on Network and Service Management - Special Issue on Efficient Management of SDN and NFV-based Systems}, keywords = {poco}, number = 1, pages = {4 - 17}, title = {Heuristic Approaches to the Controller Placement Problem in Large Scale SDN Networks}, volume = 12, year = 2015 }

  %0 Journal Article %1 info3-article-2015-131 %A Lange, Stanislav %A Gebert, Steffen %A Zinner, Thomas %A Tran-Gia, Phuoc %A Hock, David %A Jarschel, Michael %A Hoffmann, Marco %D 2015 %J IEEE Transactions on Network and Service Management - Special Issue on Efficient Management of SDN and NFV-based Systems %N 1 %P 4 - 17 %T Heuristic Approaches to the Controller Placement Problem in Large Scale SDN Networks %V 12 %X Software Defined Networking (SDN) marks a paradigm shift towards an externalized and logically centralized network control plane. A particularly important task in SDN architectures is that of controller placement, i.e., the positioning of a limited number of resources within a network in order to meet various requirements. These requirements range from latency constraints to failure tolerance and load balancing. In most scenarios, at least some of these objectives are competing, thus no single best placement is available and decision makers need to find a balanced trade-off. This work presents POCO, a framework for Pareto-based Optimal COntroller placement that provides operators with Pareto optimal placements with respect to different performance metrics. In its default configuration, POCO performs an exhaustive evaluation of all possible placements. While this is practically feasible for small and medium sized networks, realistic time and resource constraints call for an alternative in the context of large scale networks or dynamic networks whose properties change over time. For these scenarios, the POCO toolset is extended by a heuristic approach that is less accurate, but yields faster computation times. An evaluation of this heuristic is performed on a collection of real world network topologies from the Internet Topology Zoo. Utilizing a measure for quantifying the error introduced by the heuristic approach allows an analysis of the resulting trade-off between time and accuracy. Additionally, the proposed methods can be extended to solve similar virtual functions placement problems which appear in the context of Network Functions Virtualization (NFV).
• Identifying QoE Optimal Adaptation of HTTP Adaptive Streaming Based on Subjective Studies Hoßfeld, Tobias; Seufert, Michael; Sieber, Christian; Zinner, Thomas; Tran-Gia, Phuoc in Computer Networks (2015). 81 320–332.
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  HTTP Adaptive Streaming (HAS) technologies, e.g., Apple HLS or MPEG-DASH, automatically adapt the delivered video quality to the available network. This reduces stalling of the video but additionally introduces quality switches, which also influence the user-perceived Quality of Experience (QoE). In this work, we conduct a subjective study to identify the impact of adaptation parameters on QoE. The results indicate that the video quality has to be maximized first, and that the number of quality switches is less important. Based on these results, a method to compute the optimal QoE-optimal adaptation strategy for HAS on a per user basis with mixed-integer linear programming is presented. This QoE-optimal adaptation enables the benchmarking of existing adaptation algorithms for any given network condition. Moreover, the investigated concept is extended to a multi-user IPTV scenario. The question is answered whether video quality, and thereby, the QoE can be shared in a fair manner among the involved users.

  @article{info3-article-2015-132, abstract = {HTTP Adaptive Streaming (HAS) technologies, e.g., Apple HLS or MPEG-DASH, automatically adapt the delivered video quality to the available network. This reduces stalling of the video but additionally introduces quality switches, which also influence the user-perceived Quality of Experience (QoE). In this work, we conduct a subjective study to identify the impact of adaptation parameters on QoE. The results indicate that the video quality has to be maximized first, and that the number of quality switches is less important. Based on these results, a method to compute the optimal QoE-optimal adaptation strategy for HAS on a per user basis with mixed-integer linear programming is presented. This QoE-optimal adaptation enables the benchmarking of existing adaptation algorithms for any given network condition. Moreover, the investigated concept is extended to a multi-user IPTV scenario. The question is answered whether video quality, and thereby, the QoE can be shared in a fair manner among the involved users.}, author = {Hoßfeld, Tobias and Seufert, Michael and Sieber, Christian and Zinner, Thomas and Tran-Gia, Phuoc}, journal = {Computer Networks}, keywords = {sys:hidden:article}, month = 4, pages = {320-332}, title = {Identifying QoE Optimal Adaptation of HTTP Adaptive Streaming Based on Subjective Studies}, volume = 81, year = 2015 }

  %0 Journal Article %1 info3-article-2015-132 %A Hoßfeld, Tobias %A Seufert, Michael %A Sieber, Christian %A Zinner, Thomas %A Tran-Gia, Phuoc %D 2015 %J Computer Networks %P 320-332 %T Identifying QoE Optimal Adaptation of HTTP Adaptive Streaming Based on Subjective Studies %V 81 %X HTTP Adaptive Streaming (HAS) technologies, e.g., Apple HLS or MPEG-DASH, automatically adapt the delivered video quality to the available network. This reduces stalling of the video but additionally introduces quality switches, which also influence the user-perceived Quality of Experience (QoE). In this work, we conduct a subjective study to identify the impact of adaptation parameters on QoE. The results indicate that the video quality has to be maximized first, and that the number of quality switches is less important. Based on these results, a method to compute the optimal QoE-optimal adaptation strategy for HAS on a per user basis with mixed-integer linear programming is presented. This QoE-optimal adaptation enables the benchmarking of existing adaptation algorithms for any given network condition. Moreover, the investigated concept is extended to a multi-user IPTV scenario. The question is answered whether video quality, and thereby, the QoE can be shared in a fair manner among the involved users.
• Future Internet Research and Experimentation: The G-Lab Approach Schwerdel, Dennis; Reuther, Bernd; Zinner, Thomas; Müller, Paul; Tran-Gia, Phuoc in Computer Networks (2014).
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  The German Lab (G-Lab) project aims to investigate architectural concepts and technologies for a new inter-networking architecture as an integrated approach between theoretic and experimental studies. 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 are controlled by the same community to ensure that the experimental facility meets the demands of the researchers. Researchers gain access to virtualized resources or may gain exclusive access to resources if necessary. We present the current setup of the experimental facility, describing the available hardware, management of the platform, the utilization of the PlanetLab software and the user management. Moreover, a new approach to setup and deploy virtual network topologies will be described.

  @article{info3-article-2014-119, abstract = {The German Lab (G-Lab) project aims to investigate architectural concepts and technologies for a new inter-networking architecture as an integrated approach between theoretic and experimental studies. 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 are controlled by the same community to ensure that the experimental facility meets the demands of the researchers. Researchers gain access to virtualized resources or may gain exclusive access to resources if necessary. We present the current setup of the experimental facility, describing the available hardware, management of the platform, the utilization of the PlanetLab software and the user management. Moreover, a new approach to setup and deploy virtual network topologies will be described.}, author = {Schwerdel, Dennis and Reuther, Bernd and Zinner, Thomas and Müller, Paul and Tran-Gia, Phuoc}, journal = {Computer Networks}, keywords = {sys:hidden:article}, title = {Future Internet Research and Experimentation: The G-Lab Approach}, year = 2014 }

  %0 Journal Article %1 info3-article-2014-119 %A Schwerdel, Dennis %A Reuther, Bernd %A Zinner, Thomas %A Müller, Paul %A Tran-Gia, Phuoc %D 2014 %J Computer Networks %T Future Internet Research and Experimentation: The G-Lab Approach %X The German Lab (G-Lab) project aims to investigate architectural concepts and technologies for a new inter-networking architecture as an integrated approach between theoretic and experimental studies. 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 are controlled by the same community to ensure that the experimental facility meets the demands of the researchers. Researchers gain access to virtualized resources or may gain exclusive access to resources if necessary. We present the current setup of the experimental facility, describing the available hardware, management of the platform, the utilization of the PlanetLab software and the user management. Moreover, a new approach to setup and deploy virtual network topologies will be described.
• Requirement Driven Prospects for Realizing User-Centric Network Orchestration Zinner, Thomas; Hoßfeld, Tobias; Fiedler, Markus; Liers, Florian; Volkert, Thomas; Khondoker, Rahamatullah; Schatz, Raimund in Multimedia Tools and Applications (2014).
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  The Internet’s infrastructure shows severe limitations when an optimal end user experience for multimedia applications should be achieved in a resource-efficiently way. In order to realize truly user-centric networking, an information exchange between applications and networks is required. To this end, network-application interfaces need to be deployed that enable a better mediation of application data through the Internet. For smart multimedia applications and services, the application and the network should directly communicate with each other and exchange information in order to ensure an optimal Quality of Experience (QoE). In this article, we follow a use-case driven approach towards user-centric network orchestration. We derive user, application, and network requirements for three complementary use cases: HD live TV streaming, video-on-demand streaming and user authentication with high security and privacy demands, as typically required for payed multimedia services. We provide practical guidelines for achieving an optimal QoE efficiently in the context of these use cases. Based on these results, we demonstrate how to overcome one of the main limitations of today’s Internet by introducing the major steps required for user-centric network orchestration. Finally, we show conceptual prospects for realizing these steps by discussing a possible implementation with an inter-network architecture based on functional blocks.

  @article{info3-article-2014-122, abstract = {The Internet’s infrastructure shows severe limitations when an optimal end user experience for multimedia applications should be achieved in a resource-efficiently way. In order to realize truly user-centric networking, an information exchange between applications and networks is required. To this end, network-application interfaces need to be deployed that enable a better mediation of application data through the Internet. For smart multimedia applications and services, the application and the network should directly communicate with each other and exchange information in order to ensure an optimal Quality of Experience (QoE). In this article, we follow a use-case driven approach towards user-centric network orchestration. We derive user, application, and network requirements for three complementary use cases: HD live TV streaming, video-on-demand streaming and user authentication with high security and privacy demands, as typically required for payed multimedia services. We provide practical guidelines for achieving an optimal QoE efficiently in the context of these use cases. Based on these results, we demonstrate how to overcome one of the main limitations of today’s Internet by introducing the major steps required for user-centric network orchestration. Finally, we show conceptual prospects for realizing these steps by discussing a possible implementation with an inter-network architecture based on functional blocks.}, author = {Zinner, Thomas and Hoßfeld, Tobias and Fiedler, Markus and Liers, Florian and Volkert, Thomas and Khondoker, Rahamatullah and Schatz, Raimund}, journal = {Multimedia Tools and Applications}, keywords = {sys:hidden:article}, month = 6, title = {Requirement Driven Prospects for Realizing User-Centric Network Orchestration}, year = 2014 }

  %0 Journal Article %1 info3-article-2014-122 %A Zinner, Thomas %A Hoßfeld, Tobias %A Fiedler, Markus %A Liers, Florian %A Volkert, Thomas %A Khondoker, Rahamatullah %A Schatz, Raimund %D 2014 %J Multimedia Tools and Applications %T Requirement Driven Prospects for Realizing User-Centric Network Orchestration %X The Internet’s infrastructure shows severe limitations when an optimal end user experience for multimedia applications should be achieved in a resource-efficiently way. In order to realize truly user-centric networking, an information exchange between applications and networks is required. To this end, network-application interfaces need to be deployed that enable a better mediation of application data through the Internet. For smart multimedia applications and services, the application and the network should directly communicate with each other and exchange information in order to ensure an optimal Quality of Experience (QoE). In this article, we follow a use-case driven approach towards user-centric network orchestration. We derive user, application, and network requirements for three complementary use cases: HD live TV streaming, video-on-demand streaming and user authentication with high security and privacy demands, as typically required for payed multimedia services. We provide practical guidelines for achieving an optimal QoE efficiently in the context of these use cases. Based on these results, we demonstrate how to overcome one of the main limitations of today’s Internet by introducing the major steps required for user-centric network orchestration. Finally, we show conceptual prospects for realizing these steps by discussing a possible implementation with an inter-network architecture based on functional blocks.
• Close to Optimum? User-centric Evaluation of Adaptation Logics for HTTP Adaptive Streaming Hoßfeld, Tobias; Seufert, Michael; Sieber, Christian; Zinner, Thomas; Tran-Gia, Phuoc in PIK - Praxis der Informationsverarbeitung und Kommunikation (2014). 37 275–285.
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  HTTP Adaptive Streaming (HAS) is the de-facto standard for over-the-top (OTT) video streaming services. It allows to react to fluctuating network conditions on short time scales by adapting the video bit rate in order to avoid stalling of the video playback. With HAS the video content is split into small segments of a few seconds playtime each, which are available in different bit rates, i.e., quality level representations. Depending on the current conditions, the adaptation algorithm on the client side chooses the appropriate quality level and downloads the respective segment. This allows to avoid stalling, which is seen as the worst possible disturbance of HTTP video streaming, to the most possible extend. Nevertheless, the user perceived Quality of Experience (QoE) may be affected, namely by playing back lower qualities and by switching between different qualities. Therefore, adaptation algorithms are desired which maximize the user’sQoEfor the currently available network resources. Many downloading strategies have been proposed in literature, but a solid user-centric comparison of these mechanisms among each other and with the global optimum is missing. The major contributions of this work are as follows. A proper analysis of the influence of quality switches and played out representations on QoE is conducted by means of subjective user studies. The results suggest that, in order to optimize QoE, first, the quality level of the video stream has to be maximized and second, the number of quality switches should be minimized. Based on our findings, a QoEoptimization problem is formulated and the performance of our proposed algorithm is compared to other algorithms and to the QoE-optimal adaptation.

  @article{info3-article-2014-127, abstract = {HTTP Adaptive Streaming (HAS) is the de-facto standard for over-the-top (OTT) video streaming services. It allows to react to fluctuating network conditions on short time scales by adapting the video bit rate in order to avoid stalling of the video playback. With HAS the video content is split into small segments of a few seconds playtime each, which are available in different bit rates, i.e., quality level representations. Depending on the current conditions, the adaptation algorithm on the client side chooses the appropriate quality level and downloads the respective segment. This allows to avoid stalling, which is seen as the worst possible disturbance of HTTP video streaming, to the most possible extend. Nevertheless, the user perceived Quality of Experience (QoE) may be affected, namely by playing back lower qualities and by switching between different qualities. Therefore, adaptation algorithms are desired which maximize the user’sQoEfor the currently available network resources. Many downloading strategies have been proposed in literature, but a solid user-centric comparison of these mechanisms among each other and with the global optimum is missing. The major contributions of this work are as follows. A proper analysis of the influence of quality switches and played out representations on QoE is conducted by means of subjective user studies. The results suggest that, in order to optimize QoE, first, the quality level of the video stream has to be maximized and second, the number of quality switches should be minimized. Based on our findings, a QoEoptimization problem is formulated and the performance of our proposed algorithm is compared to other algorithms and to the QoE-optimal adaptation.}, author = {Hoßfeld, Tobias and Seufert, Michael and Sieber, Christian and Zinner, Thomas and Tran-Gia, Phuoc}, journal = {PIK - Praxis der Informationsverarbeitung und Kommunikation}, keywords = {sys:hidden:article}, month = 10, pages = {275-285}, title = {Close to Optimum? User-centric Evaluation of Adaptation Logics for HTTP Adaptive Streaming}, volume = 37, year = 2014 }

  %0 Journal Article %1 info3-article-2014-127 %A Hoßfeld, Tobias %A Seufert, Michael %A Sieber, Christian %A Zinner, Thomas %A Tran-Gia, Phuoc %D 2014 %J PIK - Praxis der Informationsverarbeitung und Kommunikation %P 275-285 %T Close to Optimum? User-centric Evaluation of Adaptation Logics for HTTP Adaptive Streaming %V 37 %X HTTP Adaptive Streaming (HAS) is the de-facto standard for over-the-top (OTT) video streaming services. It allows to react to fluctuating network conditions on short time scales by adapting the video bit rate in order to avoid stalling of the video playback. With HAS the video content is split into small segments of a few seconds playtime each, which are available in different bit rates, i.e., quality level representations. Depending on the current conditions, the adaptation algorithm on the client side chooses the appropriate quality level and downloads the respective segment. This allows to avoid stalling, which is seen as the worst possible disturbance of HTTP video streaming, to the most possible extend. Nevertheless, the user perceived Quality of Experience (QoE) may be affected, namely by playing back lower qualities and by switching between different qualities. Therefore, adaptation algorithms are desired which maximize the user’sQoEfor the currently available network resources. Many downloading strategies have been proposed in literature, but a solid user-centric comparison of these mechanisms among each other and with the global optimum is missing. The major contributions of this work are as follows. A proper analysis of the influence of quality switches and played out representations on QoE is conducted by means of subjective user studies. The results suggest that, in order to optimize QoE, first, the quality level of the video stream has to be maximized and second, the number of quality switches should be minimized. Based on our findings, a QoEoptimization problem is formulated and the performance of our proposed algorithm is compared to other algorithms and to the QoE-optimal adaptation.
• Interfaces, Attributes, and Use Cases: A Compass for SDN Jarschel, Michael; Zinner, Thomas; Hoßfeld, Tobias; Tran-Gia, Phuoc; Kellerer, Wolfgang in IEEE Communications Magazine (2014). 52 210–217.
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  The term Software Defined Networking (SDN) is prevalent in today’s discussion about future communication networks. As with any new term or paradigm, however, no consistent definition regarding this technology has formed. The fragmented view on SDN results in legacy products being passed off by equipment vendors as SDN, academics mixing up the attributes of SDN with those of network virtualization, and users not fully understanding the benefits. Therefore, establishing SDN as a widely adopted technology beyond laboratories and insular deployments requires a compass to navigate the multitude of ideas and concepts that make up SDN today. The contribution of this article represents an important step toward such an instrument. It gives a thorough definition of SDN and its interfaces as well as a list of its key attributes. Furthermore, a mapping of interfaces and attributes to SDN use cases is provided, highlighting the relevance of the interfaces and attributes for each scenario. This compass gives guidance to a potential adopter of SDN on whether SDN is in fact the right technology for a specific use case.

  @article{info3-article-2014-124, abstract = {The term Software Defined Networking (SDN) is prevalent in today’s discussion about future communication networks. As with any new term or paradigm, however, no consistent definition regarding this technology has formed. The fragmented view on SDN results in legacy products being passed off by equipment vendors as SDN, academics mixing up the attributes of SDN with those of network virtualization, and users not fully understanding the benefits. Therefore, establishing SDN as a widely adopted technology beyond laboratories and insular deployments requires a compass to navigate the multitude of ideas and concepts that make up SDN today. The contribution of this article represents an important step toward such an instrument. It gives a thorough definition of SDN and its interfaces as well as a list of its key attributes. Furthermore, a mapping of interfaces and attributes to SDN use cases is provided, highlighting the relevance of the interfaces and attributes for each scenario. This compass gives guidance to a potential adopter of SDN on whether SDN is in fact the right technology for a specific use case.}, author = {Jarschel, Michael and Zinner, Thomas and Hoßfeld, Tobias and Tran-Gia, Phuoc and Kellerer, Wolfgang}, journal = {IEEE Communications Magazine}, keywords = {sys:hidden:article}, month = 6, pages = {210-217}, title = {Interfaces, Attributes, and Use Cases: A Compass for SDN}, volume = 52, year = 2014 }

  %0 Journal Article %1 info3-article-2014-124 %A Jarschel, Michael %A Zinner, Thomas %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %A Kellerer, Wolfgang %D 2014 %J IEEE Communications Magazine %P 210-217 %T Interfaces, Attributes, and Use Cases: A Compass for SDN %V 52 %X The term Software Defined Networking (SDN) is prevalent in today’s discussion about future communication networks. As with any new term or paradigm, however, no consistent definition regarding this technology has formed. The fragmented view on SDN results in legacy products being passed off by equipment vendors as SDN, academics mixing up the attributes of SDN with those of network virtualization, and users not fully understanding the benefits. Therefore, establishing SDN as a widely adopted technology beyond laboratories and insular deployments requires a compass to navigate the multitude of ideas and concepts that make up SDN today. The contribution of this article represents an important step toward such an instrument. It gives a thorough definition of SDN and its interfaces as well as a list of its key attributes. Furthermore, a mapping of interfaces and attributes to SDN use cases is provided, highlighting the relevance of the interfaces and attributes for each scenario. This compass gives guidance to a potential adopter of SDN on whether SDN is in fact the right technology for a specific use case.
• Software defined Networks - Das Internet flexibler gestalten und dynamischer steuern Zinner, Thomas; Hoßfeld, Tobias; Tran-Gia, Phuoc; Kellerer, Wolfgang in ITG Mitgliederbeilage / VDE dialog (invited article) (2013). 6–9.
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  Vor allem aufgrund seiner starren Architektur und mangelnden Ressourcennutzung ist die Flexibilität der aktuellen Internettechnologie eingeschränkt. Dies könnte sich durch Anwendung von Software Defined Networks (SDN) ändern. Hierbei wird die Steuerung der Netze und Datenflüsse von den bisherigen Netzkomponenten auf eine zentrale logische Einheit übertragen.

  @article{info3-article-2013-115, abstract = {Vor allem aufgrund seiner starren Architektur und mangelnden Ressourcennutzung ist die Flexibilität der aktuellen Internettechnologie eingeschränkt. Dies könnte sich durch Anwendung von Software Defined Networks (SDN) ändern. Hierbei wird die Steuerung der Netze und Datenflüsse von den bisherigen Netzkomponenten auf eine zentrale logische Einheit übertragen.}, author = {Zinner, Thomas and Hoßfeld, Tobias and Tran-Gia, Phuoc and Kellerer, Wolfgang}, journal = {ITG Mitgliederbeilage / VDE dialog (invited article)}, keywords = {sys:hidden:article}, month = 10, pages = {6-9}, title = {Software defined Networks - Das Internet flexibler gestalten und dynamischer steuern}, year = 2013 }

  %0 Journal Article %1 info3-article-2013-115 %A Zinner, Thomas %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %A Kellerer, Wolfgang %D 2013 %J ITG Mitgliederbeilage / VDE dialog (invited article) %P 6-9 %T Software defined Networks - Das Internet flexibler gestalten und dynamischer steuern %X Vor allem aufgrund seiner starren Architektur und mangelnden Ressourcennutzung ist die Flexibilität der aktuellen Internettechnologie eingeschränkt. Dies könnte sich durch Anwendung von Software Defined Networks (SDN) ändern. Hierbei wird die Steuerung der Netze und Datenflüsse von den bisherigen Netzkomponenten auf eine zentrale logische Einheit übertragen.
• Performance Evaluation of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization Zinner, Thomas; Tutschku, Kurt; Nakao, Akihiro; Tran-Gia, Phuoc in JCNDS Special Issue on: Network Virtualization - Concepts and Performance Aspects (2011). Vol. 6 322–340.
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  From the viewpoint of communication networks Network Virtualization (NV) extends beyond pure operational issues and addresses many 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. We provide a simulation framework based on discrete event simulation which allows an evaluation of the re-sequencing buffer occupancy. Further, we perform an analysis of the fundamental behaviors and factors for packet re-ordering in concurrent multipath transmissions.

  @article{info3-article-2011-74, abstract = {From the viewpoint of communication networks Network Virtualization (NV) extends beyond pure operational issues and addresses many 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. We provide a simulation framework based on discrete event simulation which allows an evaluation of the re-sequencing buffer occupancy. Further, we perform an analysis of the fundamental behaviors and factors for packet re-ordering in concurrent multipath transmissions.}, author = {Zinner, Thomas and Tutschku, Kurt and Nakao, Akihiro and Tran-Gia, Phuoc}, journal = {JCNDS Special Issue on: Network Virtualization - Concepts and Performance Aspects}, keywords = {sys:hidden:article}, month = 5, pages = {322-340}, title = {Performance Evaluation of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization}, volume = {Vol. 6}, year = 2011 }

  %0 Journal Article %1 info3-article-2011-74 %A Zinner, Thomas %A Tutschku, Kurt %A Nakao, Akihiro %A Tran-Gia, Phuoc %D 2011 %J JCNDS Special Issue on: Network Virtualization - Concepts and Performance Aspects %P 322-340 %T Performance Evaluation of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization %V Vol. 6 %X From the viewpoint of communication networks Network Virtualization (NV) extends beyond pure operational issues and addresses many 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. We provide a simulation framework based on discrete event simulation which allows an evaluation of the re-sequencing buffer occupancy. Further, we perform an analysis of the fundamental behaviors and factors for packet re-ordering in concurrent multipath transmissions.

• Mobile Networks and Management Agüero, Ramón; Zinner, Thomas; García-Lozano, Mario; Wenning, Bernd-Ludwig; Timm-Giel, Andreas (2016). Springer, Santander, Spain.
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  @book{info3-book-2016-1, address = {Santander, Spain}, author = {Agüero, Ramón and Zinner, Thomas and García-Lozano, Mario and Wenning, Bernd-Ludwig and Timm-Giel, Andreas}, booktitle = {6th International Conference (MONAMI 2014), September 22-26, 2014, Revised Selected Papers}, keywords = {sys:hidden:book}, publisher = {Springer}, title = {Mobile Networks and Management}, year = 2016 }

  %0 Book %1 info3-book-2016-1 %A Agüero, Ramón %A Zinner, Thomas %A García-Lozano, Mario %A Wenning, Bernd-Ludwig %A Timm-Giel, Andreas %B 6th International Conference (MONAMI 2014), September 22-26, 2014, Revised Selected Papers %C Santander, Spain %D 2016 %I Springer %T Mobile Networks and Management
• Mobile Networks and Management: 6th International Conference (MONAMI 2014), September 22-26, 2014, Revised Selected Papers Band 141 von Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering Agüero, Ramón; Zinner, Thomas; Goleva, Rossitza; Timm-Giel, Andreas; Tran-Gia, Phuoc (2015). Springer, Würzburg, Germany.
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  @book{info3-book-2015-16, address = {Würzburg, Germany}, author = {Agüero, Ramón and Zinner, Thomas and Goleva, Rossitza and Timm-Giel, Andreas and Tran-Gia, Phuoc}, keywords = {sys:hidden:book}, publisher = {Springer}, title = {Mobile Networks and Management: 6th International Conference (MONAMI 2014), September 22-26, 2014, Revised Selected Papers Band 141 von Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering}, year = 2015 }

  %0 Book %1 info3-book-2015-16 %A Agüero, Ramón %A Zinner, Thomas %A Goleva, Rossitza %A Timm-Giel, Andreas %A Tran-Gia, Phuoc %C Würzburg, Germany %D 2015 %I Springer %T Mobile Networks and Management: 6th International Conference (MONAMI 2014), September 22-26, 2014, Revised Selected Papers Band 141 von Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering

• QoE Management for Future Networks Schatz, Raimund; Schwarzmann, Susanna; Zinner, Thomas; Dobrijevic, Ognjen; Liotou, Eirini; Pocta, Peter; Baraković, Sabina; Baraković Husić, Jasmina; Skorin-Kapov, Lea in Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms and Tools (2018).
  • [ Abstract ]
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  This chapter discusses prospects of QoE management for future networks and applications. After motivating QoE management, it first provides an introduction to the concept by discussing its origins, key terms and giving an overview of the most relevant existing theoretical frameworks. Then, recent research on promising technical approaches to QoE- driven management that operate across different layers of the networking stack is discussed. Finally, the chapter provides conclusions and an outlook on the future of QoE management with a focus on those key enablers (including cooperation, business models and key technologies) that are essential for ultimately turning QoE-aware network and application management into reality.

  @incollection{info3-incollection-2018-1, abstract = {This chapter discusses prospects of QoE management for future networks and applications. After motivating QoE management, it first provides an introduction to the concept by discussing its origins, key terms and giving an overview of the most relevant existing theoretical frameworks. Then, recent research on promising technical approaches to QoE- driven management that operate across different layers of the networking stack is discussed. Finally, the chapter provides conclusions and an outlook on the future of QoE management with a focus on those key enablers (including cooperation, business models and key technologies) that are essential for ultimately turning QoE-aware network and application management into reality.}, author = {Schatz, Raimund and Schwarzmann, Susanna and Zinner, Thomas and Dobrijevic, Ognjen and Liotou, Eirini and Pocta, Peter and Baraković, Sabina and Baraković Husić, Jasmina and Skorin-Kapov, Lea}, booktitle = {Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms and Tools}, keywords = {ngn}, publisher = {Springer}, title = {QoE Management for Future Networks}, year = 2018 }

  %0 Book Section %1 info3-incollection-2018-1 %A Schatz, Raimund %A Schwarzmann, Susanna %A Zinner, Thomas %A Dobrijevic, Ognjen %A Liotou, Eirini %A Pocta, Peter %A Baraković, Sabina %A Baraković Husić, Jasmina %A Skorin-Kapov, Lea %B Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms and Tools %D 2018 %I Springer %T QoE Management for Future Networks %X This chapter discusses prospects of QoE management for future networks and applications. After motivating QoE management, it first provides an introduction to the concept by discussing its origins, key terms and giving an overview of the most relevant existing theoretical frameworks. Then, recent research on promising technical approaches to QoE- driven management that operate across different layers of the networking stack is discussed. Finally, the chapter provides conclusions and an outlook on the future of QoE management with a focus on those key enablers (including cooperation, business models and key technologies) that are essential for ultimately turning QoE-aware network and application management into reality.
• Big-Data Helps SDN to Improve Application Specific Quality of Service Schwarzmann, Susanna; Blenk, Andreas; Dobrijevic, Ognjen; Jarschel, Michael; Hotho, Andreas; Zinner, Thomas; Wamser, Florian in Big Data and Software Defined Networks (2018).
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  This chapter first provides an outline of the current results in the domains of: (a) quality-of-service (QoS) / quality-of-experience (QoE) control and management (CaM) for real-time multimedia services that is supported by software-defined networking (SDN), and (b) big data analytics and methods that are used for QoS/QoE CaM. Then, three specific use case scenarios with respect to video streaming services are presented, so as to illustrate the expected benefits of incorporating big data analytics into SDN-based CaM for the purposes of improving or optimizing QoS/QoE. In the end, we describe our vision and a high-level view of an SDN-based architecture for QoS/QoE CaM that is enriched with big data analytics' functional blocks and summarize corresponding challenges.

  @incollection{info3-incollection-2018-2, abstract = {This chapter first provides an outline of the current results in the domains of: (a) quality-of-service (QoS) / quality-of-experience (QoE) control and management (CaM) for real-time multimedia services that is supported by software-defined networking (SDN), and (b) big data analytics and methods that are used for QoS/QoE CaM. Then, three specific use case scenarios with respect to video streaming services are presented, so as to illustrate the expected benefits of incorporating big data analytics into SDN-based CaM for the purposes of improving or optimizing QoS/QoE. In the end, we describe our vision and a high-level view of an SDN-based architecture for QoS/QoE CaM that is enriched with big data analytics' functional blocks and summarize corresponding challenges.}, author = {Schwarzmann, Susanna and Blenk, Andreas and Dobrijevic, Ognjen and Jarschel, Michael and Hotho, Andreas and Zinner, Thomas and Wamser, Florian}, booktitle = {Big Data and Software Defined Networks}, keywords = {dfg-sdn}, month = 3, publisher = {Institution of Engineering and Technology (IET)}, title = {Big-Data Helps SDN to Improve Application Specific Quality of Service}, year = 2018 }

  %0 Book Section %1 info3-incollection-2018-2 %A Schwarzmann, Susanna %A Blenk, Andreas %A Dobrijevic, Ognjen %A Jarschel, Michael %A Hotho, Andreas %A Zinner, Thomas %A Wamser, Florian %B Big Data and Software Defined Networks %D 2018 %I Institution of Engineering and Technology (IET) %T Big-Data Helps SDN to Improve Application Specific Quality of Service %X This chapter first provides an outline of the current results in the domains of: (a) quality-of-service (QoS) / quality-of-experience (QoE) control and management (CaM) for real-time multimedia services that is supported by software-defined networking (SDN), and (b) big data analytics and methods that are used for QoS/QoE CaM. Then, three specific use case scenarios with respect to video streaming services are presented, so as to illustrate the expected benefits of incorporating big data analytics into SDN-based CaM for the purposes of improving or optimizing QoS/QoE. In the end, we describe our vision and a high-level view of an SDN-based architecture for QoS/QoE CaM that is enriched with big data analytics' functional blocks and summarize corresponding challenges.
• Matching Requirements for Ambient Assisted Living and Enhanced Living Environments with Networking Technologies Zinner, Thomas; Wamser, Florian; Leopold, Helmut; Dobre, Ciprian; Mavromoustakis, Constandinos X.; Garcia, Nuno M. in Ambient Assisted Living and Enhanced Living Environments, C. Dobre, C. X. Mavromoustakis, N. M. Garcia, R. I. Goleva, G. Mastorakis (eds.) (2016).
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  @incollection{info3-incollection-2016-1, author = {Zinner, Thomas and Wamser, Florian and Leopold, Helmut and Dobre, Ciprian and Mavromoustakis, Constandinos X. and Garcia, Nuno M.}, booktitle = {Ambient Assisted Living and Enhanced Living Environments}, editor = {Dobre, Ciprian and Mavromoustakis, Constandinos X. and Garcia, Nuno M. and Goleva, Rossitza I. and Mastorakis, George}, keywords = {myown}, month = 11, publisher = {Elsevier}, title = {Matching Requirements for Ambient Assisted Living and Enhanced Living Environments with Networking Technologies}, year = 2016 }

  %0 Book Section %1 info3-incollection-2016-1 %A Zinner, Thomas %A Wamser, Florian %A Leopold, Helmut %A Dobre, Ciprian %A Mavromoustakis, Constandinos X. %A Garcia, Nuno M. %B Ambient Assisted Living and Enhanced Living Environments %D 2016 %E Dobre, Ciprian %E Mavromoustakis, Constandinos X. %E Garcia, Nuno M. %E Goleva, Rossitza I. %E Mastorakis, George %I Elsevier %T Matching Requirements for Ambient Assisted Living and Enhanced Living Environments with Networking Technologies
• Green Wireless Energy Efficiency in Wireless Networks Bernardo, Vitor; Braun, Torsten; Curado, Marilia; Fiedler, Markus; Hock, David; Hossmann, Theus; Hummel, Karin A.; Hurni, Philipp; Ickin, Selim; Jamakovic, Almerima; Nadjm-Tehrani, Simin; Ahn Trinh, Tuan; Jon Vergara, Ekhiotz; Wamser, Florian; Zinner, Thomas in Large-scale Distributed Systems and Energy Efficiency: A Holistic View, J.-M. Pierson (ed.) (2015).
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  Summary Wireless networks have become more and more popular because of ease of installation, ease of access, and support of smart terminals and gadgets on the move. In the overall life cycle of providing green wireless technology, from production to operation and, finally, removal, this chapter focuses on the operation phase and summarizes insights in energy consumption of major technologies. The chapter also focuses on the edge of the network, comprising network access points (APs) and mobile user devices. It discusses particularities of most important wireless networking technologies: wireless access networks including 3G/LTE and wireless mesh networks (WMNs); wireless sensor networks (WSNs); and ad-hoc and opportunistic networks. Concerning energy efficiency, the chapter discusses challenges in access, wireless sensor, and ad-hoc and opportunistic networks.

  @incollection{info3-incollection-2014-23, abstract = {Summary Wireless networks have become more and more popular because of ease of installation, ease of access, and support of smart terminals and gadgets on the move. In the overall life cycle of providing green wireless technology, from production to operation and, finally, removal, this chapter focuses on the operation phase and summarizes insights in energy consumption of major technologies. The chapter also focuses on the edge of the network, comprising network access points (APs) and mobile user devices. It discusses particularities of most important wireless networking technologies: wireless access networks including 3G/LTE and wireless mesh networks (WMNs); wireless sensor networks (WSNs); and ad-hoc and opportunistic networks. Concerning energy efficiency, the chapter discusses challenges in access, wireless sensor, and ad-hoc and opportunistic networks.}, author = {Bernardo, Vitor and Braun, Torsten and Curado, Marilia and Fiedler, Markus and Hock, David and Hossmann, Theus and Hummel, Karin A. and Hurni, Philipp and Ickin, Selim and Jamakovic, Almerima and Nadjm-Tehrani, Simin and Ahn Trinh, Tuan and Jon Vergara, Ekhiotz and Wamser, Florian and Zinner, Thomas}, booktitle = {Large-scale Distributed Systems and Energy Efficiency: A Holistic View}, editor = {Pierson, Jean-Marc}, keywords = {myown}, month = 3, publisher = {John Wiley & Sons, Ltd}, title = {Green Wireless Energy Efficiency in Wireless Networks}, year = 2015 }

  %0 Book Section %1 info3-incollection-2014-23 %A Bernardo, Vitor %A Braun, Torsten %A Curado, Marilia %A Fiedler, Markus %A Hock, David %A Hossmann, Theus %A Hummel, Karin A. %A Hurni, Philipp %A Ickin, Selim %A Jamakovic, Almerima %A Nadjm-Tehrani, Simin %A Ahn Trinh, Tuan %A Jon Vergara, Ekhiotz %A Wamser, Florian %A Zinner, Thomas %B Large-scale Distributed Systems and Energy Efficiency: A Holistic View %D 2015 %E Pierson, Jean-Marc %I John Wiley & Sons, Ltd %T Green Wireless Energy Efficiency in Wireless Networks %X Summary Wireless networks have become more and more popular because of ease of installation, ease of access, and support of smart terminals and gadgets on the move. In the overall life cycle of providing green wireless technology, from production to operation and, finally, removal, this chapter focuses on the operation phase and summarizes insights in energy consumption of major technologies. The chapter also focuses on the edge of the network, comprising network access points (APs) and mobile user devices. It discusses particularities of most important wireless networking technologies: wireless access networks including 3G/LTE and wireless mesh networks (WMNs); wireless sensor networks (WSNs); and ad-hoc and opportunistic networks. Concerning energy efficiency, the chapter discusses challenges in access, wireless sensor, and ad-hoc and opportunistic networks.
• Multipath Routing Slice Experiments in Federated Testbeds Zseby, Tanja; Zinner, Thomas; Tutschku, Kurt; Shavitt, Yuval; Tran-Gia, Phuoc; Schwartz, Christian; Rafetseder, Albert; Henke, Christian; Schmoll, Carsten in Future Internet Assembly (FIA) Book Future Internet: Achievements and Promising Technology, J. Domingue, A. Galis, A. Gavras, T. Zahariadis, D. Lambert, F. Cleary, P. Daras, S. Krco, H. Müller, M.-S. Li (eds.) (2011).
  • [ Abstract ]
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  The Internet today consist of many heterogeneous infras- tructures, owned and maintained by separate and potentially competing administrative authorities. On top of this a wide variety of applications has different requirements with regard to quality, reliability and security from the underlying networks. The number of stakeholders who partici- pate in provisioning of network and services is growing. More demanding applications (like eGovernment, eHealth, critical and emergency infras- tructures) are on the rise. Therefore we assume that these two basic characteristics, a) multiple authorities and b) applications with very di- verse demands, are likely to stay or even increase in the Internet of the future. In such an environment federation and virtualization of resources are key features that should be supported in a future Internet. The ability to form slices across domains that meet application specific requirements enables many of the desired features in future networks. In this paper, we present a Multipath Routing Slice experiment that we performed over multiple federated testbeds. We combined capabilities from different experimental facilities, since one single testbed did not offer all the required capabilities. This paper summarizes the conducted experiment, our experience with the usability of federated testbeds and our experience with the use of advanced measurement technologies within experimental facilities. We believe that this experiment provides a good example use case for the future Internet itself because we assume that the Internet will consist of multiple different infrastructures that have to be combined in application specific overlays or routing slices, very much like the experimental facilities we used in this experiment. We also assume that the growing demands will push towards a much better measurement instrumentation of the future Internet. The tools used in our experiment can provide a starting point for this.

  @incollection{info3-incollection-2011-15, abstract = {The Internet today consist of many heterogeneous infras- tructures, owned and maintained by separate and potentially competing administrative authorities. On top of this a wide variety of applications has different requirements with regard to quality, reliability and security from the underlying networks. The number of stakeholders who partici- pate in provisioning of network and services is growing. More demanding applications (like eGovernment, eHealth, critical and emergency infras- tructures) are on the rise. Therefore we assume that these two basic characteristics, a) multiple authorities and b) applications with very di- verse demands, are likely to stay or even increase in the Internet of the future. In such an environment federation and virtualization of resources are key features that should be supported in a future Internet. The ability to form slices across domains that meet application specific requirements enables many of the desired features in future networks. In this paper, we present a Multipath Routing Slice experiment that we performed over multiple federated testbeds. We combined capabilities from different experimental facilities, since one single testbed did not offer all the required capabilities. This paper summarizes the conducted experiment, our experience with the usability of federated testbeds and our experience with the use of advanced measurement technologies within experimental facilities. We believe that this experiment provides a good example use case for the future Internet itself because we assume that the Internet will consist of multiple different infrastructures that have to be combined in application specific overlays or routing slices, very much like the experimental facilities we used in this experiment. We also assume that the growing demands will push towards a much better measurement instrumentation of the future Internet. The tools used in our experiment can provide a starting point for this.}, author = {Zseby, Tanja and Zinner, Thomas and Tutschku, Kurt and Shavitt, Yuval and Tran-Gia, Phuoc and Schwartz, Christian and Rafetseder, Albert and Henke, Christian and Schmoll, Carsten}, booktitle = {Future Internet Assembly (FIA) Book Future Internet: Achievements and Promising Technology}, editor = {Domingue, John and Galis, Alex and Gavras, Anastasius and Zahariadis, Theodore and Lambert, Dave and Cleary, Frances and Daras, Patros and Krco, Srdjan and Müller, Henning and Li, Man-Sze}, keywords = {myown}, month = 5, publisher = {Springer}, title = {Multipath Routing Slice Experiments in Federated Testbeds}, year = 2011 }

  %0 Book Section %1 info3-incollection-2011-15 %A Zseby, Tanja %A Zinner, Thomas %A Tutschku, Kurt %A Shavitt, Yuval %A Tran-Gia, Phuoc %A Schwartz, Christian %A Rafetseder, Albert %A Henke, Christian %A Schmoll, Carsten %B Future Internet Assembly (FIA) Book Future Internet: Achievements and Promising Technology %D 2011 %E Domingue, John %E Galis, Alex %E Gavras, Anastasius %E Zahariadis, Theodore %E Lambert, Dave %E Cleary, Frances %E Daras, Patros %E Krco, Srdjan %E Müller, Henning %E Li, Man-Sze %I Springer %T Multipath Routing Slice Experiments in Federated Testbeds %X The Internet today consist of many heterogeneous infras- tructures, owned and maintained by separate and potentially competing administrative authorities. On top of this a wide variety of applications has different requirements with regard to quality, reliability and security from the underlying networks. The number of stakeholders who partici- pate in provisioning of network and services is growing. More demanding applications (like eGovernment, eHealth, critical and emergency infras- tructures) are on the rise. Therefore we assume that these two basic characteristics, a) multiple authorities and b) applications with very di- verse demands, are likely to stay or even increase in the Internet of the future. In such an environment federation and virtualization of resources are key features that should be supported in a future Internet. The ability to form slices across domains that meet application specific requirements enables many of the desired features in future networks. In this paper, we present a Multipath Routing Slice experiment that we performed over multiple federated testbeds. We combined capabilities from different experimental facilities, since one single testbed did not offer all the required capabilities. This paper summarizes the conducted experiment, our experience with the usability of federated testbeds and our experience with the use of advanced measurement technologies within experimental facilities. We believe that this experiment provides a good example use case for the future Internet itself because we assume that the Internet will consist of multiple different infrastructures that have to be combined in application specific overlays or routing slices, very much like the experimental facilities we used in this experiment. We also assume that the growing demands will push towards a much better measurement instrumentation of the future Internet. The tools used in our experiment can provide a starting point for this.

• 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 = 3, 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
• 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 = 2, 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
• Web Performance Pitfalls Enghardt, Theresa; Zinner, Thomas; Feldmann, Anja in Passive and Active Measurement Conference (PAM) (2019).
  • [ BibTeX ]
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  @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 = 3, 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
• 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 = 2, 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
• 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 = 4, 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
• 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 = 3, 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.
• 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) (2018).
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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 = 7, 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.
• 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 (2018).
  • [ BibTeX ]
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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 = 5, 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
• 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” (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 = 2, 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.
• 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 ]
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  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 = 4, 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.
• 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 ]
  • [ BibTeX ]
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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 = 8, 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.
• 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) (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 = 7, 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.
• 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
• 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 (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 = 5, 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.
• 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 = 2, 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
• 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 = 2, 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.
• 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) (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
• 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 = 2, 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.
• 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 = 9, 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
• 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 = 2, 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.
• 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) (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 = 5, 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.
• 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) (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 = 8, 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.
• 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) (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.
• Collecting Subjective Ratings in Enterprise Environments Borchert, Kathrin; Hirth, Matthias; Zinner, Thomas; Göritz, Anja in 9th International Conference on Quality of Multimedia Experience (QoMEX) (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 = 5, 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
• 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) (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.
• 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) (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 = 9, 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.
• Performance Analysis of Hierarchical Caching Systems with Bandwidth Constraints Burger, Valentin; Zinner, Thomas in Proceedings of the International Telecommunication Networks and Applications Conference (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.
• 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) (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 = 5, 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.
• 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) (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
• 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) (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 = 9, 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
• 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) (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.
• 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 = 9, 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
• 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) (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 = 9, 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.
• 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 (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 = 7, 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) (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 = 6, 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.
• 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) (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 = 5, 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.
• 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 (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 = 6, 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
• 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) (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 = 3, 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.
• 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) (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 = 9, 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.
• 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) (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 = 9, 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) (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 = 9, 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.
• 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 (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.
• 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 (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 = 5, 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.
• 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) (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 = 9, 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
• 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) (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 = 8, 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
• 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) (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 = 9, 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
• 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 (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 = 9, 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.
• 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) (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 = 8, 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.
• 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) (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 = 7, 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.
• 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) (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 = 5, 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.
• 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) (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 = 9, 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.
• 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) (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.
• 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) (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.
• 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 (2013). 172–187.
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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 = 9, 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.
• 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) (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 = 9, 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.
• 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 (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 = 8, 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.
• 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 (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 = 5, 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.
• 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) (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 = 5, 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.
• 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) (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 = 9, 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.
• 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) (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 = 9, 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.
• 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) (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 = 8, 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
• 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’ (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 = 1, 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
• 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 (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 = 6, 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.
• 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) (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 = 5, 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.
• 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) (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 = 6, 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.
• 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 = 8, 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
• 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) (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 = 6, 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
• 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) (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.
• 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) (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 = 6, 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.
• 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) (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 = 6, 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.
• 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 (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 = 2, 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.
• 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 (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 = 3, 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.
• 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 (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 = 8, 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
• 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 (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 = 3, 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.
• 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 (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 = 6, 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 (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 = 6, 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.
• 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) (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 = 9, 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.
• 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 (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 = 5, 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
• 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 (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 = 5, 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
• Network Virtualization: Implementation Steps Towards the Future Internet Tutschku, Kurt; Zinner, Thomas; Nakao, Akihiro; Tran-Gia, Phuoc in KiVS 2009 (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 = 3, 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.
• 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 (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 = 3, 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 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 (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
• 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) (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 = 9, 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.

• Automation und Digitalisierung - Potenzial und Einsatz von Blockchain- und Distributed-Ledger-Technologien in der Automatisierungstechnik Skwarek, Volker; Reher, Julian; Geissler, Stefan; Zinner, Thomas (2019, February).
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  @misc{info3-misc-2019-1, author = {Skwarek, Volker and Reher, Julian and Geissler, Stefan and Zinner, Thomas}, howpublished = {Zentralverband Elektrotechnik- und Elektroindustrie}, keywords = {sys:hidden:misc}, month = 2, title = {Automation und Digitalisierung - Potenzial und Einsatz von Blockchain- und Distributed-Ledger-Technologien in der Automatisierungstechnik}, year = 2019 }

  %0 Generic %1 info3-misc-2019-1 %A Skwarek, Volker %A Reher, Julian %A Geissler, Stefan %A Zinner, Thomas %D 2019 %T Automation und Digitalisierung - Potenzial und Einsatz von Blockchain- und Distributed-Ledger-Technologien in der Automatisierungstechnik
• Enhancing SDN Security by Device Fingerprinting Gray, Nicholas; Zinner, Thomas; Tran-Gia, Phuoc (2017, May).
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  Software-defined Networking (SDN) provides an increased flexibility and cost savings by separating the data from the control plane. Despite these benefits, this separation also results in a greater attack surface as new devices and protocols are deployed. OpenFlow is one of these protocols and enables the communication between the switch and the controller. Ideally this connection takes place over an encrypted TLS channel, but as this feature is marked optional, it is not supported by all devices. This allows an attacker to eavesdrop and alter the communication, hence resulting in a comprised network. In this work, we demonstrate a new approach for authentication based on device fingerprinting to enhance the security in scenarios, where cryptographic mechanisms are unavailable.

  @misc{info3-demo-2017-2, abstract = {Software-defined Networking (SDN) provides an increased flexibility and cost savings by separating the data from the control plane. Despite these benefits, this separation also results in a greater attack surface as new devices and protocols are deployed. OpenFlow is one of these protocols and enables the communication between the switch and the controller. Ideally this connection takes place over an encrypted TLS channel, but as this feature is marked optional, it is not supported by all devices. This allows an attacker to eavesdrop and alter the communication, hence resulting in a comprised network. In this work, we demonstrate a new approach for authentication based on device fingerprinting to enhance the security in scenarios, where cryptographic mechanisms are unavailable.}, author = {Gray, Nicholas and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {15th IFIP/IEEE International Symposium on Integrated Network Management (IM), Lisbon, Portugal, May 2017}, keywords = {sardine}, month = 5, title = {Enhancing SDN Security by Device Fingerprinting}, year = 2017 }

  %0 Generic %1 info3-demo-2017-2 %A Gray, Nicholas %A Zinner, Thomas %A Tran-Gia, Phuoc %B 15th IFIP/IEEE International Symposium on Integrated Network Management (IM), Lisbon, Portugal, May 2017 %D 2017 %T Enhancing SDN Security by Device Fingerprinting %X Software-defined Networking (SDN) provides an increased flexibility and cost savings by separating the data from the control plane. Despite these benefits, this separation also results in a greater attack surface as new devices and protocols are deployed. OpenFlow is one of these protocols and enables the communication between the switch and the controller. Ideally this connection takes place over an encrypted TLS channel, but as this feature is marked optional, it is not supported by all devices. This allows an attacker to eavesdrop and alter the communication, hence resulting in a comprised network. In this work, we demonstrate a new approach for authentication based on device fingerprinting to enhance the security in scenarios, where cryptographic mechanisms are unavailable.
• SDN/NFV-enabled Security Architecture for Fine-grained Policy Enforcement and Threat Mitigation for Enterprise Networks Pfaff, Benedikt; Scherer, Johann; Hock, David; Gray, Nicholas; Zinner, Thomas; Tran-Gia, Phuoc; Durner, Raphael; Kellerer, Wolfgang; Lorenz, Claas (2017, August).
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  Network Functions Visualization (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 hardware. 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.

  @misc{info3-demo-2017-3, abstract = {Network Functions Visualization (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 hardware. 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.}, author = {Pfaff, Benedikt and Scherer, Johann and Hock, David and Gray, Nicholas and Zinner, Thomas and Tran-Gia, Phuoc and Durner, Raphael and Kellerer, Wolfgang and Lorenz, Claas}, booktitle = {In Proceedings of the SIGCOMM Posters and Demos}, keywords = {sardine}, month = 8, title = {SDN/NFV-enabled Security Architecture for Fine-grained Policy Enforcement and Threat Mitigation for Enterprise Networks}, year = 2017 }

  %0 Generic %1 info3-demo-2017-3 %A Pfaff, Benedikt %A Scherer, Johann %A Hock, David %A Gray, Nicholas %A Zinner, Thomas %A Tran-Gia, Phuoc %A Durner, Raphael %A Kellerer, Wolfgang %A Lorenz, Claas %B In Proceedings of the SIGCOMM Posters and Demos %D 2017 %T SDN/NFV-enabled Security Architecture for Fine-grained Policy Enforcement and Threat Mitigation for Enterprise Networks %X Network Functions Visualization (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 hardware. 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.
• Demonstrating a Personalized Secure-By-Default Bring Your Own Device Solution Based on Software Defined Networking Gebert, Steffen; Zinner, Thomas; Gray, Nicholas; Durner, Raphael; Lorenz, Class; Lange, Stanislav (2016, September).
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  Network virtualization is one classical use-case for Software Defined Networks (SDN). By programmatically instantiating virtual networks, traffic from one or more devices can be separated or connectivity can be established as needed. S- BYOD, which is presented in this demonstration, applies the SDN concept to Bring Your Own Device (BYOD) scenarios and offers personalized virtual networks that are set up and extended on demand. This is done once the user authenticates, activates access to additional applications, or as soon as applications scale out and involve more servers. The described proof-of-concept implementation explores, to what degree an agent-less BYOD solution, based only on SDN, can lower the attack surface by explicit user opt-ins for particular services. Further, an assessment of the number of required rules within the flow tables of switches completes this work.

  @misc{info3-demo-2016-1, abstract = {Network virtualization is one classical use-case for Software Defined Networks (SDN). By programmatically instantiating virtual networks, traffic from one or more devices can be separated or connectivity can be established as needed. S- BYOD, which is presented in this demonstration, applies the SDN concept to Bring Your Own Device (BYOD) scenarios and offers personalized virtual networks that are set up and extended on demand. This is done once the user authenticates, activates access to additional applications, or as soon as applications scale out and involve more servers. The described proof-of-concept implementation explores, to what degree an agent-less BYOD solution, based only on SDN, can lower the attack surface by explicit user opt-ins for particular services. Further, an assessment of the number of required rules within the flow tables of switches completes this work.}, address = {Würzburg, Germany}, author = {Gebert, Steffen and Zinner, Thomas and Gray, Nicholas and Durner, Raphael and Lorenz, Class and Lange, Stanislav}, booktitle = {28th International Teletraffic Congress (ITC 28)}, keywords = {sardine}, month = 9, title = {Demonstrating a Personalized Secure-By-Default Bring Your Own Device Solution Based on Software Defined Networking}, year = 2016 }

  %0 Generic %1 info3-demo-2016-1 %A Gebert, Steffen %A Zinner, Thomas %A Gray, Nicholas %A Durner, Raphael %A Lorenz, Class %A Lange, Stanislav %B 28th International Teletraffic Congress (ITC 28) %C Würzburg, Germany %D 2016 %T Demonstrating a Personalized Secure-By-Default Bring Your Own Device Solution Based on Software Defined Networking %X Network virtualization is one classical use-case for Software Defined Networks (SDN). By programmatically instantiating virtual networks, traffic from one or more devices can be separated or connectivity can be established as needed. S- BYOD, which is presented in this demonstration, applies the SDN concept to Bring Your Own Device (BYOD) scenarios and offers personalized virtual networks that are set up and extended on demand. This is done once the user authenticates, activates access to additional applications, or as soon as applications scale out and involve more servers. The described proof-of-concept implementation explores, to what degree an agent-less BYOD solution, based only on SDN, can lower the attack surface by explicit user opt-ins for particular services. Further, an assessment of the number of required rules within the flow tables of switches completes this work.
• Continuously Delivering Your Network Gebert, Steffen; Schwartz, Christian; Zinner, Thomas; Tran-Gia, Phuoc (2015, May).
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  @misc{info3-poster-2015-37, 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 = {sys:hidden:poster}, month = 5, title = {Continuously Delivering Your Network}, year = 2015 }

  %0 Generic %1 info3-poster-2015-37 %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
• Demonstrating the Prospects of Dynamic Application-Aware Networking in a Home Environment Wamser, Florian; Zinner, Thomas; Iffländer, Lukas; Tran-Gia, Phuoc (2014, August).
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  @misc{info3-software-2014-20, address = {Chicago, IL, USA}, author = {Wamser, Florian and Zinner, Thomas and Iffländer, Lukas and Tran-Gia, Phuoc}, keywords = {sys:hidden:software}, month = 8, title = {Demonstrating the Prospects of Dynamic Application-Aware Networking in a Home Environment}, year = 2014 }

  %0 Generic %1 info3-software-2014-20 %A Wamser, Florian %A Zinner, Thomas %A Iffländer, Lukas %A Tran-Gia, Phuoc %C Chicago, IL, USA %D 2014 %T Demonstrating the Prospects of Dynamic Application-Aware Networking in a Home Environment
• POCO: A Framework for the Pareto-Optimal Resilient Controller Placement in SDN-based Core Networks Hock, David; Gebert, Steffen; Hartmann, Matthias; Zinner, Thomas; Tran-Gia, Phuoc (2014, May).
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  @misc{info3-software-2014-18, address = {Krakow, Poland}, author = {Hock, David and Gebert, Steffen and Hartmann, Matthias and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {IEEE NOMS}, keywords = {poco}, month = 5, title = {POCO: A Framework for the Pareto-Optimal Resilient Controller Placement in SDN-based Core Networks}, year = 2014 }

  %0 Generic %1 info3-software-2014-18 %A Hock, David %A Gebert, Steffen %A Hartmann, Matthias %A Zinner, Thomas %A Tran-Gia, Phuoc %B IEEE NOMS %C Krakow, Poland %D 2014 %T POCO: A Framework for the Pareto-Optimal Resilient Controller Placement in SDN-based Core Networks
• Demonstrating the Optimal Placement of Virtualized Cellular Network Functions in Case of Large Crowd Events Gebert, Steffen; Hock, David; Zinner, Thomas; Tran-Gia, Phuoc; Hoffmann, Marco; Jarschel, Michael; Schmidt, Ernst-Dieter; Braun, Ralf-Peter; Banse, Christian; Koepsel, Andreas (2014, August).
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  @misc{info3-software-2014-21, author = {Gebert, Steffen and Hock, David and Zinner, Thomas and Tran-Gia, Phuoc and Hoffmann, Marco and Jarschel, Michael and Schmidt, Ernst-Dieter and Braun, Ralf-Peter and Banse, Christian and Koepsel, Andreas}, booktitle = {SIGCOMM}, keywords = {sys:hidden:software}, month = 8, title = {Demonstrating the Optimal Placement of Virtualized Cellular Network Functions in Case of Large Crowd Events}, year = 2014 }

  %0 Generic %1 info3-software-2014-21 %A Gebert, Steffen %A Hock, David %A Zinner, Thomas %A Tran-Gia, Phuoc %A Hoffmann, Marco %A Jarschel, Michael %A Schmidt, Ernst-Dieter %A Braun, Ralf-Peter %A Banse, Christian %A Koepsel, Andreas %B SIGCOMM %D 2014 %T Demonstrating the Optimal Placement of Virtualized Cellular Network Functions in Case of Large Crowd Events
• POCO-PLC: Enabling Dynamic Pareto-Optimal Resilient Controller Placement in SDN Networks Hock, David; Hartmann, Matthias; Gebert, Steffen; Zinner, Thomas; Tran-Gia, Phuoc (2014, April).
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  • [ EndNote ]
  @misc{info3-software-2014-19, address = {Toronto, Canada}, author = {Hock, David and Hartmann, Matthias and Gebert, Steffen and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {Computer Communications Workshops (INFOCOM WKSHPS)}, keywords = {poco}, month = 4, title = {POCO-PLC: Enabling Dynamic Pareto-Optimal Resilient Controller Placement in SDN Networks}, year = 2014 }

  %0 Generic %1 info3-software-2014-19 %A Hock, David %A Hartmann, Matthias %A Gebert, Steffen %A Zinner, Thomas %A Tran-Gia, Phuoc %B Computer Communications Workshops (INFOCOM WKSHPS) %C Toronto, Canada %D 2014 %T POCO-PLC: Enabling Dynamic Pareto-Optimal Resilient Controller Placement in SDN Networks
• Demonstrating the Benefit of Joint Application and Network Control Within a Wireless Access Network Wamser, Florian; Hock, David; Seufert, Michael; Zinner, Thomas; Tran-Gia, Phuoc (2013, April).
  • [ BibTeX ]
  • [ EndNote ]
  • [ Download ]
  @misc{info3-software-2013-16, address = {Turin, Italy}, author = {Wamser, Florian and Hock, David and Seufert, Michael and Zinner, Thomas and Tran-Gia, Phuoc}, booktitle = {2013 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS)}, keywords = {sys:hidden:software}, month = 4, title = {Demonstrating the Benefit of Joint Application and Network Control Within a Wireless Access Network}, year = 2013 }

  %0 Generic %1 info3-software-2013-16 %A Wamser, Florian %A Hock, David %A Seufert, Michael %A Zinner, Thomas %A Tran-Gia, Phuoc %B 2013 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS) %C Turin, Italy %D 2013 %T Demonstrating the Benefit of Joint Application and Network Control Within a Wireless Access Network

• Performance evaluation of novel network and application paradigms and management approaches Zinner, Thomas PhD thesis, University of Wuerzburg. (2017, October).
  • [ BibTeX ]
  • [ EndNote ]
  @phdthesis{info3-habilitation-2017-1, author = {Zinner, Thomas}, keywords = {sys:hidden:habilitation}, month = 10, school = {University of Wuerzburg}, title = {Performance evaluation of novel network and application paradigms and management approaches}, year = 2017 }

  %0 Thesis %1 info3-habilitation-2017-1 %A Zinner, Thomas %D 2017 %T Performance evaluation of novel network and application paradigms and management approaches
• Performance Modeling of QoE-Aware Multipath Video Transmission in the Future Internet Zinner, Thomas (2012, August).
  • [ BibTeX ]
  • [ EndNote ]
  • [ Download ]
  @phdthesis{info3-dissertation-2012-32, author = {Zinner, Thomas}, keywords = {sys:hidden:dissertation}, month = 8, title = {Performance Modeling of QoE-Aware Multipath Video Transmission in the Future Internet}, year = 2012 }

  %0 Thesis %1 info3-dissertation-2012-32 %A Zinner, Thomas %D 2012 %T Performance Modeling of QoE-Aware Multipath Video Transmission in the Future Internet

• QoE-Aware Service And Network Management for Video Streaming Zinner, Thomas (2017, September 20).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-presentation-2017-7, address = {NewNet@Paris Lab, Telecom ParisTech, France (http://perso.telecom-paristech.fr/ drossi/index.php?n=Main.Seminar#KEY20170920)}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 9, title = {QoE-Aware Service And Network Management for Video Streaming}, year = 2017 }

  %0 Generic %1 info3-presentation-2017-7 %A Zinner, Thomas %C NewNet@Paris Lab, Telecom ParisTech, France (http://perso.telecom-paristech.fr/~drossi/index.php?n=Main.Seminar#KEY20170920) %D 2017 %T QoE-Aware Service And Network Management for Video Streaming
• SDN/NFV-enabled Security Architecture for Enterprise Networks Pfaff, Benedikt; Lorenz, Class; Durner, Raphael; Zinner, Thomas (2017, September 28).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-presentation-2017-8, address = {Infosim® Global Webinar Day (https://www.infosim.net/resources/webinars/sdn-nfv-enabled-security-architecture-for-enterprise-networks-global-webinar-day-september-28th-2017/)}, author = {Pfaff, Benedikt and Lorenz, Class and Durner, Raphael and Zinner, Thomas}, keywords = {sardine}, month = 9, title = {SDN/NFV-enabled Security Architecture for Enterprise Networks}, year = 2017 }

  %0 Generic %1 info3-presentation-2017-8 %A Pfaff, Benedikt %A Lorenz, Class %A Durner, Raphael %A Zinner, Thomas %C Infosim® Global Webinar Day (https://www.infosim.net/resources/webinars/sdn-nfv-enabled-security-architecture-for-enterprise-networks-global-webinar-day-september-28th-2017/) %D 2017 %T SDN/NFV-enabled Security Architecture for Enterprise Networks
• Performance Issues in SDN and NFV Tran-Gia, Phuoc; Zinner, Thomas; Gebert, Steffen (2015, May 7).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2015-492, address = {University of Toronto}, author = {Tran-Gia, Phuoc and Zinner, Thomas and Gebert, Steffen}, keywords = {sys:hidden:presentation}, month = 5, title = {Performance Issues in SDN and NFV}, year = 2015 }

  %0 Generic %1 info3-talk-2015-492 %A Tran-Gia, Phuoc %A Zinner, Thomas %A Gebert, Steffen %C University of Toronto %D 2015 %T Performance Issues in SDN and NFV
• Analyse des Kundenfeedbacks zu IT-Anwendungen Zinner, Thomas; Hirth, Matthias (2014, November 27).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2014-489, address = {Datev Trendscout, Nürnberg, Germany}, author = {Zinner, Thomas and Hirth, Matthias}, keywords = {sys:hidden:presentation}, month = 11, title = {Analyse des Kundenfeedbacks zu IT-Anwendungen}, year = 2014 }

  %0 Generic %1 info3-talk-2014-489 %A Zinner, Thomas %A Hirth, Matthias %C Datev Trendscout, Nürnberg, Germany %D 2014 %T Analyse des Kundenfeedbacks zu IT-Anwendungen
• Dynamic Application-Aware Resource Management using Software-Defined Networking: Implementation Prospects and Challenges Zinner, Thomas (2014, May 9).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2014-477, address = {Krakau}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 5, title = {Dynamic Application-Aware Resource Management using Software-Defined Networking: Implementation Prospects and Challenges}, year = 2014 }

  %0 Generic %1 info3-talk-2014-477 %A Zinner, Thomas %C Krakau %D 2014 %T Dynamic Application-Aware Resource Management using Software-Defined Networking: Implementation Prospects and Challenges
• Ambient Assisted Living Zinner, Thomas; Burger, Valentin (2014, November 27).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2014-490, address = {Datev Trendscout, Nürnberg, Germany}, author = {Zinner, Thomas and Burger, Valentin}, keywords = {sys:hidden:presentation}, month = 11, title = {Ambient Assisted Living}, year = 2014 }

  %0 Generic %1 info3-talk-2014-490 %A Zinner, Thomas %A Burger, Valentin %C Datev Trendscout, Nürnberg, Germany %D 2014 %T Ambient Assisted Living
• QoE Management für Cloud Anwendungen Hoßfeld, Tobias; Zinner, Thomas (2014, July 3).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2014-478, address = {NMI 2014 – Neue Medien in der Informationsgesellschaft, Berlin}, author = {Hoßfeld, Tobias and Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 7, title = {QoE Management für Cloud Anwendungen}, year = 2014 }

  %0 Generic %1 info3-talk-2014-478 %A Hoßfeld, Tobias %A Zinner, Thomas %C NMI 2014 – Neue Medien in der Informationsgesellschaft, Berlin %D 2014 %T QoE Management für Cloud Anwendungen
• Alles wird smarter: Sind SDN die Smart-Netze der Zukunft? Zinner, Thomas (2013, June 4).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2013-467, address = {Panel@DFN Forum, Universität Erlangen}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 6, title = {Alles wird smarter: Sind SDN die Smart-Netze der Zukunft?}, year = 2013 }

  %0 Generic %1 info3-talk-2013-467 %A Zinner, Thomas %C Panel@DFN Forum, Universität Erlangen %D 2013 %T Alles wird smarter: Sind SDN die Smart-Netze der Zukunft?
• Streaming Video over Unreliable and Bandwidth Limited Networks, as opponent at the Ph.D. Defense of Hussein Aziz Zinner, Thomas (2013, June 10).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2013-468, address = {BTH Karlskrona, Sweden}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 6, title = {Streaming Video over Unreliable and Bandwidth Limited Networks, as opponent at the Ph.D. Defense of Hussein Aziz}, year = 2013 }

  %0 Generic %1 info3-talk-2013-468 %A Zinner, Thomas %C BTH Karlskrona, Sweden %D 2013 %T Streaming Video over Unreliable and Bandwidth Limited Networks, as opponent at the Ph.D. Defense of Hussein Aziz
• SDN-based Application-Aware Networking on the Example of YouTube Video Streaming Jarschel, Michael; Wamser, Florian; Höhn, Thomas; Zinner, Thomas; Tran-Gia, Phuoc (2013, October 11).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2013-473, address = {2nd European Workshop on Software Defined Networks (EWSDN 2013), Berlin, Germany}, author = {Jarschel, Michael and Wamser, Florian and Höhn, Thomas and Zinner, Thomas and Tran-Gia, Phuoc}, keywords = {demobenefit}, month = 10, title = {SDN-based Application-Aware Networking on the Example of YouTube Video Streaming}, year = 2013 }

  %0 Generic %1 info3-talk-2013-473 %A Jarschel, Michael %A Wamser, Florian %A Höhn, Thomas %A Zinner, Thomas %A Tran-Gia, Phuoc %C 2nd European Workshop on Software Defined Networks (EWSDN 2013), Berlin, Germany %D 2013 %T SDN-based Application-Aware Networking on the Example of YouTube Video Streaming
• On the Accuracy of Leveraging SDN for Passive Network Measurements Jarschel, Michael; Zinner, Thomas; Höhn, Thomas; Tran-Gia, Phuoc (2013, November 20).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2013-475, address = {Australasian Telecommunication Networks & Applications Conference (ATNAC 2013), Christchurch, New Zealand}, author = {Jarschel, Michael and Zinner, Thomas and Höhn, Thomas and Tran-Gia, Phuoc}, keywords = {sys:hidden:presentation}, month = 11, title = {On the Accuracy of Leveraging SDN for Passive Network Measurements}, year = 2013 }

  %0 Generic %1 info3-talk-2013-475 %A Jarschel, Michael %A Zinner, Thomas %A Höhn, Thomas %A Tran-Gia, Phuoc %C Australasian Telecommunication Networks & Applications Conference (ATNAC 2013), Christchurch, New Zealand %D 2013 %T On the Accuracy of Leveraging SDN for Passive Network Measurements
• SJRP Pruno: Prospects for Realizing User-Centric Network Orchestration Zinner, Thomas; Liers, Florian (2012, June 26).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2012-445, address = {NGI 2012, Karlskrona}, author = {Zinner, Thomas and Liers, Florian}, keywords = {sys:hidden:presentation}, month = 6, title = {SJRP Pruno: Prospects for Realizing User-Centric Network Orchestration}, year = 2012 }

  %0 Generic %1 info3-talk-2012-445 %A Zinner, Thomas %A Liers, Florian %C NGI 2012, Karlskrona %D 2012 %T SJRP Pruno: Prospects for Realizing User-Centric Network Orchestration
• The G-Lab Perspective on Content-Aware Networks Zinner, Thomas (2012, July 7).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2012-447, address = {CHIST-ERA Conference, Edinburgh}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 7, title = {The G-Lab Perspective on Content-Aware Networks}, year = 2012 }

  %0 Generic %1 info3-talk-2012-447 %A Zinner, Thomas %C CHIST-ERA Conference, Edinburgh %D 2012 %T The G-Lab Perspective on Content-Aware Networks
• MultiNext: Measuring Concurrent Multipath Transmissions in an Experimental Facility Zinner, Thomas; Tutschku, Kurt; Zseby, Tanja (2011, June 28).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2011-420, address = {7th Euro-Nf Conference on Next Generation Internet}, author = {Zinner, Thomas and Tutschku, Kurt and Zseby, Tanja}, keywords = {sys:hidden:presentation}, month = 6, title = {MultiNext: Measuring Concurrent Multipath Transmissions in an Experimental Facility}, year = 2011 }

  %0 Generic %1 info3-talk-2011-420 %A Zinner, Thomas %A Tutschku, Kurt %A Zseby, Tanja %C 7th Euro-Nf Conference on Next Generation Internet %D 2011 %T MultiNext: Measuring Concurrent Multipath Transmissions in an Experimental Facility
• Performance of Concurrent Multipath Transmissions - Measurements and Model Validation Zinner, Thomas (2011, June 28).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2011-421, address = {7th Conference on Next Generation Internet Networks}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 6, title = {Performance of Concurrent Multipath Transmissions - Measurements and Model Validation}, year = 2011 }

  %0 Generic %1 info3-talk-2011-421 %A Zinner, Thomas %C 7th Conference on Next Generation Internet Networks %D 2011 %T Performance of Concurrent Multipath Transmissions - Measurements and Model Validation
• Supporting Scalable Video Codecs in a P2P Video-on-Demand Streaming System Zinner, Thomas (2010, March 3).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2010-364, address = {Miyazaki, Japan}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 3, title = {Supporting Scalable Video Codecs in a P2P Video-on-Demand Streaming System}, year = 2010 }

  %0 Generic %1 info3-talk-2010-364 %A Zinner, Thomas %C Miyazaki, Japan %D 2010 %T Supporting Scalable Video Codecs in a P2P Video-on-Demand Streaming System
• Using Concurrent Multipath Transmission for Transport Virtualization: Analyzing Path Selection Zinner, Thomas (2010, April 23).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2010-368, address = {FG5.2.1 Workshop: Technik und Grenzen der Virtualisierung}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 4, title = {Using Concurrent Multipath Transmission for Transport Virtualization: Analyzing Path Selection}, year = 2010 }

  %0 Generic %1 info3-talk-2010-368 %A Zinner, Thomas %C FG5.2.1 Workshop: Technik und Grenzen der Virtualisierung %D 2010 %T Using Concurrent Multipath Transmission for Transport Virtualization: Analyzing Path Selection
• Using Concurrent Multipath Transmission for Transport Virtualization: Analyzing Path Selection. Zinner, Thomas (2010, September 8).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2010-389, address = {22nd International Teletraffic Congress (ITC22), Amsterdam, The Netherlands}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 9, title = {Using Concurrent Multipath Transmission for Transport Virtualization: Analyzing Path Selection.}, year = 2010 }

  %0 Generic %1 info3-talk-2010-389 %A Zinner, Thomas %C 22nd International Teletraffic Congress (ITC22), Amsterdam, The Netherlands %D 2010 %T Using Concurrent Multipath Transmission for Transport Virtualization: Analyzing Path Selection.
• QoE of Video Service Hoßfeld, Tobias; Zinner, Thomas (2010, September 20).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2010-394, address = {Workshop for E-Plus, Düsseldorf}, author = {Hoßfeld, Tobias and Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 9, title = {QoE of Video Service}, year = 2010 }

  %0 Generic %1 info3-talk-2010-394 %A Hoßfeld, Tobias %A Zinner, Thomas %C Workshop for E-Plus, Düsseldorf %D 2010 %T QoE of Video Service
• Towards QoE Management for Scalable Video Coding Zinner, Thomas (2010, March 3).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2010-363, address = {Miyazaki, Japan}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 3, title = {Towards QoE Management for Scalable Video Coding}, year = 2010 }

  %0 Generic %1 info3-talk-2010-363 %A Zinner, Thomas %C Miyazaki, Japan %D 2010 %T Towards QoE Management for Scalable Video Coding
• QoE Management with Scalable Video Coding in a P2P Video-on-Demand Streaming System Zinner, Thomas (2010, March 1).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2010-362, address = {Osaka University, Osaka, Japan}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 3, title = {QoE Management with Scalable Video Coding in a P2P Video-on-Demand Streaming System}, year = 2010 }

  %0 Generic %1 info3-talk-2010-362 %A Zinner, Thomas %C Osaka University, Osaka, Japan %D 2010 %T QoE Management with Scalable Video Coding in a P2P Video-on-Demand Streaming System
• Concurrent Multipath Transmissions for Live Video Streaming Zinner, Thomas (2010, August 4).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2010-387, address = {G-Lab Status Meeting, Wuerzburg}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 8, title = {Concurrent Multipath Transmissions for Live Video Streaming}, year = 2010 }

  %0 Generic %1 info3-talk-2010-387 %A Zinner, Thomas %C G-Lab Status Meeting, Wuerzburg %D 2010 %T Concurrent Multipath Transmissions for Live Video Streaming
• Enhancing the User Perceived Quality for Live Video Streaming with Concurrent Multipath Transmissions Zinner, Thomas (2010, July 6).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2010-384, address = {EuroNF Plenary Meeting Lisbon}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 7, title = {Enhancing the User Perceived Quality for Live Video Streaming with Concurrent Multipath Transmissions}, year = 2010 }

  %0 Generic %1 info3-talk-2010-384 %A Zinner, Thomas %C EuroNF Plenary Meeting Lisbon %D 2010 %T Enhancing the User Perceived Quality for Live Video Streaming with Concurrent Multipath Transmissions
• Performance of Concurrent Multipath Transmissions Zinner, Thomas (2010, July 7).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2010-385, address = {EuroNF Plenary Meeting Lisbon}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 7, title = {Performance of Concurrent Multipath Transmissions}, year = 2010 }

  %0 Generic %1 info3-talk-2010-385 %A Zinner, Thomas %C EuroNF Plenary Meeting Lisbon %D 2010 %T Performance of Concurrent Multipath Transmissions
• Performance Evaluation of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization Zinner, Thomas (2009, May 20).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2009-349, address = {Hoi An, Viet nam}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 5, title = {Performance Evaluation of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization}, year = 2009 }

  %0 Generic %1 info3-talk-2009-349 %A Zinner, Thomas %C Hoi An, Viet nam %D 2009 %T Performance Evaluation of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization
• Malwareerkennung und Frühwarnsysteme Zinner, Thomas (2009, July 30).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2009-348, address = {Datev Trendscout, Nürnberg}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 7, title = {Malwareerkennung und Frühwarnsysteme}, year = 2009 }

  %0 Generic %1 info3-talk-2009-348 %A Zinner, Thomas %C Datev Trendscout, Nürnberg %D 2009 %T Malwareerkennung und Frühwarnsysteme
• Controlling QoE of Scalable Video Codecs for Future Video Streaming Systems Zinner, Thomas; Hoßfeld, Tobias (2009, September 18).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2009-351, address = {Telecom ParisTech, Paris 13, France}, author = {Zinner, Thomas and Hoßfeld, Tobias}, keywords = {sys:hidden:presentation}, month = 9, title = {Controlling QoE of Scalable Video Codecs for Future Video Streaming Systems}, year = 2009 }

  %0 Generic %1 info3-talk-2009-351 %A Zinner, Thomas %A Hoßfeld, Tobias %C Telecom ParisTech, Paris 13, France %D 2009 %T Controlling QoE of Scalable Video Codecs for Future Video Streaming Systems
• Zukünftige Zugangsinfrastrukturen Martin, Rüdiger; Pries, Rastin; Zinner, Thomas (2008, July 24).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2008-318, address = {Datev Trendscout, Nürnberg}, author = {Martin, Rüdiger and Pries, Rastin and Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 7, title = {Zukünftige Zugangsinfrastrukturen}, year = 2008 }

  %0 Generic %1 info3-talk-2008-318 %A Martin, Rüdiger %A Pries, Rastin %A Zinner, Thomas %C Datev Trendscout, Nürnberg %D 2008 %T Zukünftige Zugangsinfrastrukturen
• Performance Evaluation of the Information Sink in a Multi-Probe Statistical Anomaly Detection System Zinner, Thomas (2008, December 8).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2008-333, address = {Australasian Telecommunication Networks and Applications Conference, Adelaide, Australia}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 12, title = {Performance Evaluation of the Information Sink in a Multi-Probe Statistical Anomaly Detection System}, year = 2008 }

  %0 Generic %1 info3-talk-2008-333 %A Zinner, Thomas %C Australasian Telecommunication Networks and Applications Conference, Adelaide, Australia %D 2008 %T Performance Evaluation of the Information Sink in a Multi-Probe Statistical Anomaly Detection System
• Transitionspfade zu IPv6 Zinner, Thomas; Hartmann, Matthias (2008, November 27).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2008-330, address = {Datev Trendscout, Nürnberg}, author = {Zinner, Thomas and Hartmann, Matthias}, keywords = {sys:hidden:presentation}, month = 11, title = {Transitionspfade zu IPv6}, year = 2008 }

  %0 Generic %1 info3-talk-2008-330 %A Zinner, Thomas %A Hartmann, Matthias %C Datev Trendscout, Nürnberg %D 2008 %T Transitionspfade zu IPv6
• G-Lab: A Future Generation Internet Research Lab Zinner, Thomas (2008, December 2).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2008-331, address = {Panel Discussion during the International Conference on Parallel and Distributed Computing, Applications and Technologies, Dunedin}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 12, title = {G-Lab: A Future Generation Internet Research Lab}, year = 2008 }

  %0 Generic %1 info3-talk-2008-331 %A Zinner, Thomas %C Panel Discussion during the International Conference on Parallel and Distributed Computing, Applications and Technologies, Dunedin %D 2008 %T G-Lab: A Future Generation Internet Research Lab
• Supporting Vertical Handover by Using a Pastry Peer-to-Peer Overlay Network Zinner, Thomas (2008, February 27).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2008-269, address = {Euro-FGI Annual Plenary Meeting, Salerno, Italy}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 2, title = {Supporting Vertical Handover by Using a Pastry Peer-to-Peer Overlay Network}, year = 2008 }

  %0 Generic %1 info3-talk-2008-269 %A Zinner, Thomas %C Euro-FGI Annual Plenary Meeting, Salerno, Italy %D 2008 %T Supporting Vertical Handover by Using a Pastry Peer-to-Peer Overlay Network
• On the Trade-off between Efficiency and Congestion in Location-aware Overlay Networks - Example of a Vertical Handover Support System Zinner, Thomas (2008, September 11).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2008-325, address = {P2P'2008, Aachen}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 9, title = {On the Trade-off between Efficiency and Congestion in Location-aware Overlay Networks - Example of a Vertical Handover Support System}, year = 2008 }

  %0 Generic %1 info3-talk-2008-325 %A Zinner, Thomas %C P2P'2008, Aachen %D 2008 %T On the Trade-off between Efficiency and Congestion in Location-aware Overlay Networks - Example of a Vertical Handover Support System
• Performance Evaluation of the Information Sink in a Multi-Probe Statistical Anomaly Detection System Zinner, Thomas (2008, December 5).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2008-332, address = {University of Canterbury, Christchurch, New Zealand}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 12, title = {Performance Evaluation of the Information Sink in a Multi-Probe Statistical Anomaly Detection System}, year = 2008 }

  %0 Generic %1 info3-talk-2008-332 %A Zinner, Thomas %C University of Canterbury, Christchurch, New Zealand %D 2008 %T Performance Evaluation of the Information Sink in a Multi-Probe Statistical Anomaly Detection System
• Leistungsuntersuchung von Sendestrategien in IT-Frühwarninfrastrukturen Zinner, Thomas (2008, April 3).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2008-270, address = {3. Essener Workshop}, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 4, title = {Leistungsuntersuchung von Sendestrategien in IT-Frühwarninfrastrukturen}, year = 2008 }

  %0 Generic %1 info3-talk-2008-270 %A Zinner, Thomas %C 3. Essener Workshop %D 2008 %T Leistungsuntersuchung von Sendestrategien in IT-Frühwarninfrastrukturen
• Architekturoptionen für eine sichere und zuverlässige IT-Frühwarnarchitektur Zinner, Thomas (2007, August 30).
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-talk-2007-256, author = {Zinner, Thomas}, keywords = {sys:hidden:presentation}, month = 8, title = {Architekturoptionen für eine sichere und zuverlässige IT-Frühwarnarchitektur}, year = 2007 }

  %0 Generic %1 info3-talk-2007-256 %A Zinner, Thomas %D 2007 %T Architekturoptionen für eine sichere und zuverlässige IT-Frühwarnarchitektur

• Discrete-Time Analysis: Deriving the Distribution of the Number of Events in an Arbitrarily Distributed Interval Gebert, Steffen; Zinner, Thomas; Lange, Stanislav; Schwartz, Christian; Tran-Gia, Phuoc (2016).
  • [ BibTeX ]
  • [ EndNote ]
  • [ Download ]
  @techreport{info3-techreport-2016-1, author = {Gebert, Steffen and Zinner, Thomas and Lange, Stanislav and Schwartz, Christian and Tran-Gia, Phuoc}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = 6, number = 498, title = {Discrete-Time Analysis: Deriving the Distribution of the Number of Events in an Arbitrarily Distributed Interval}, year = 2016 }

  %0 Report %1 info3-techreport-2016-1 %A Gebert, Steffen %A Zinner, Thomas %A Lange, Stanislav %A Schwartz, Christian %A Tran-Gia, Phuoc %D 2016 %N 498 %T Discrete-Time Analysis: Deriving the Distribution of the Number of Events in an Arbitrarily Distributed Interval
• Agile Management of Software Based Networks Gebert, Steffen; Schwartz, Christian; Zinner, Thomas; Tran-Gia, Phuoc (2015).
  • [ BibTeX ]
  • [ EndNote ]
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  @techreport{info3-techreport-2015-267, author = {Gebert, Steffen and Schwartz, Christian and Zinner, Thomas and Tran-Gia, Phuoc}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = 1, number = 493, title = {Agile Management of Software Based Networks}, year = 2015 }

  %0 Report %1 info3-techreport-2015-267 %A Gebert, Steffen %A Schwartz, Christian %A Zinner, Thomas %A Tran-Gia, Phuoc %D 2015 %N 493 %T Agile Management of Software Based Networks
• Crowdsourced Subjective User Study Results on QoE Influence Factors of HTTP Adaptive Streaming Hoßfeld, Tobias; Seufert, Michael; Sieber, Christian; Zinner, Thomas (2014).
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  @techreport{info3-techreport-2014-265, author = {Hoßfeld, Tobias and Seufert, Michael and Sieber, Christian and Zinner, Thomas}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = 7, number = 491, title = {Crowdsourced Subjective User Study Results on QoE Influence Factors of HTTP Adaptive Streaming}, year = 2014 }

  %0 Report %1 info3-techreport-2014-265 %A Hoßfeld, Tobias %A Seufert, Michael %A Sieber, Christian %A Zinner, Thomas %D 2014 %N 491 %T Crowdsourced Subjective User Study Results on QoE Influence Factors of HTTP Adaptive Streaming
• A Survey on Quality of Experience of HTTP Adaptive Streaming Seufert, Michael; Egger, Sebastian; Slanina, Martin; Zinner, Thomas; Hoßfeld, Tobias; Tran-Gia, Phuoc (2014).
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  @techreport{info3-techreport-2014-264, author = {Seufert, Michael and Egger, Sebastian and Slanina, Martin and Zinner, Thomas and Hoßfeld, Tobias and Tran-Gia, Phuoc}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = 4, number = 490, title = {A Survey on Quality of Experience of HTTP Adaptive Streaming}, year = 2014 }

  %0 Report %1 info3-techreport-2014-264 %A Seufert, Michael %A Egger, Sebastian %A Slanina, Martin %A Zinner, Thomas %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %D 2014 %N 490 %T A Survey on Quality of Experience of HTTP Adaptive Streaming
• A Compass Through SDN Networks Zinner, Thomas; Jarschel, Michael; Hoßfeld, Tobias; Tran-Gia, Phuoc; Kellerer, Wolfgang (2013).
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  @techreport{info3-techreport-2013-262, author = {Zinner, Thomas and Jarschel, Michael and Hoßfeld, Tobias and Tran-Gia, Phuoc and Kellerer, Wolfgang}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = 10, number = 488, title = {A Compass Through SDN Networks}, year = 2013 }

  %0 Report %1 info3-techreport-2013-262 %A Zinner, Thomas %A Jarschel, Michael %A Hoßfeld, Tobias %A Tran-Gia, Phuoc %A Kellerer, Wolfgang %D 2013 %N 488 %T A Compass Through SDN Networks
• Transport Protocol Influences on YouTube QoE Hoßfeld, Tobias; Zinner, Thomas; Schatz, Raimund; Seufert, Michael; Tran-Gia, Phuoc (2011).
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  @techreport{info3-techreport-2011-258, author = {Hoßfeld, Tobias and Zinner, Thomas and Schatz, Raimund and Seufert, Michael and Tran-Gia, Phuoc}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = 7, number = 482, title = {Transport Protocol Influences on YouTube QoE}, year = 2011 }

  %0 Report %1 info3-techreport-2011-258 %A Hoßfeld, Tobias %A Zinner, Thomas %A Schatz, Raimund %A Seufert, Michael %A Tran-Gia, Phuoc %D 2011 %N 482 %T Transport Protocol Influences on YouTube QoE
• Measurement-based Topology and Performance Investigations of D-A-CH Research Networks Klein, Dominik; Tutschku, Kurt; Zinner, Thomas (2010).
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  @techreport{info3-techreport-2010-253, author = {Klein, Dominik and Tutschku, Kurt and Zinner, Thomas}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = 8, number = 473, title = {Measurement-based Topology and Performance Investigations of D-A-CH Research Networks}, year = 2010 }

  %0 Report %1 info3-techreport-2010-253 %A Klein, Dominik %A Tutschku, Kurt %A Zinner, Thomas %D 2010 %N 473 %T Measurement-based Topology and Performance Investigations of D-A-CH Research Networks
• An Analytical Model for the Evaluation of the Information Processing in Multi-Probe Networks Zinner, Thomas; Staehle, Dirk; Oechsner, Simon; Tran-Gia, Phuoc; Tutschku, Kurt (2009).
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  @techreport{info3-techreport-2009-244, author = {Zinner, Thomas and Staehle, Dirk and Oechsner, Simon and Tran-Gia, Phuoc and Tutschku, Kurt}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = 3, number = 456, title = {An Analytical Model for the Evaluation of the Information Processing in Multi-Probe Networks}, year = 2009 }

  %0 Report %1 info3-techreport-2009-244 %A Zinner, Thomas %A Staehle, Dirk %A Oechsner, Simon %A Tran-Gia, Phuoc %A Tutschku, Kurt %D 2009 %N 456 %T An Analytical Model for the Evaluation of the Information Processing in Multi-Probe Networks
• Influence of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization Tutschku, Kurt; Zinner, Thomas; Nakao, Akihiro; Tran-Gia, Phuoc (2009).
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  @techreport{info3-techreport-2009-242, author = {Tutschku, Kurt and Zinner, Thomas and Nakao, Akihiro and Tran-Gia, Phuoc}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, number = 452, title = {Influence of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization}, year = 2009 }

  %0 Report %1 info3-techreport-2009-242 %A Tutschku, Kurt %A Zinner, Thomas %A Nakao, Akihiro %A Tran-Gia, Phuoc %D 2009 %N 452 %T Influence of Packet Re-ordering on Concurrent Multipath Transmissions for Transport Virtualization