Alexej Grigorjew M. Sc.

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

  @inproceedings{info3-inproceedings-2023-5, abstract = {Resource reservation is a fundamental mechanism for ensuring quality of service in time-sensitive networks, which can be decentralized by using reservation protocols. In the Ethernet technology Time-Sensitive Networking, this has been proposed in conjunction with the Credit-Based Shaper. For the reservation, the standards assume a maximum worst-case latency bound at each hop. However, we will show through formal analysis and simulation that these worst-case latency bounds are not safe. To face this, we propose an extension to the current standards to allow the reservation of time-sensitive traffic with reliable latency guarantees. The effectiveness of our approach is demonstrated through simulations of both synthetic and industrial networks. Finally, by providing additional information about neighboring devices, we could further increase the maximum reservable traffic by up to 20% in our test cases.}, author = {Maile, Lisa and Voitlein, Dominik and Grigorjew, Alexej and Hielscher, Kai-Steffen J. and German, Reinhard}, booktitle = {31st International Conference on Real-Time Networks and Systems}, keywords = {can}, month = 6, title = {On the Validity of Credit-Based Shaper Delay Guarantees in Decentralized Reservation Protocols}, year = 2023 }

  %0 Conference Paper %1 info3-inproceedings-2023-5 %A Maile, Lisa %A Voitlein, Dominik %A Grigorjew, Alexej %A Hielscher, Kai-Steffen J. %A German, Reinhard %B 31st International Conference on Real-Time Networks and Systems %D 2023 %T On the Validity of Credit-Based Shaper Delay Guarantees in Decentralized Reservation Protocols %X Resource reservation is a fundamental mechanism for ensuring quality of service in time-sensitive networks, which can be decentralized by using reservation protocols. In the Ethernet technology Time-Sensitive Networking, this has been proposed in conjunction with the Credit-Based Shaper. For the reservation, the standards assume a maximum worst-case latency bound at each hop. However, we will show through formal analysis and simulation that these worst-case latency bounds are not safe. To face this, we propose an extension to the current standards to allow the reservation of time-sensitive traffic with reliable latency guarantees. The effectiveness of our approach is demonstrated through simulations of both synthetic and industrial networks. Finally, by providing additional information about neighboring devices, we could further increase the maximum reservable traffic by up to 20% in our test cases.

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

  @inproceedings{info3-inproceedings-2022-15, abstract = {Recent developments in the Time Sensitive Networking (TSN) group have put forth a number of mechanisms to improve deterministic latency in layer 2 switches. Their shaping approaches differ with respect to prerequisites, flexibility, maximum latency, and latency variation (jitter). Asynchronous solutions provide flexibility in dynamic scenarios, but Credit-Based Shaping (CBS) and Asynchronous Traffic Shaping (ATS) come with a high latency variance, as the minimum latency is not affected by them. Some applications in industrial and automotive use cases require low jitter while trying to avoid a dependency on time synchronization, and even TSN's redundancy mechanism benefits from a lower latency variance. This work is bridging the gap between low-jitter transmission requirements and asynchronous shaping mechanisms. In this paper, the application of a stateless Asynchronous Constant Delay Shaper (ACDS) is discussed. It collects the queuing duration from the previous bridge to delay each frame for the remaining time such that a constant per-hop delay for each frame is achieved. The discussion includes the prerequisites, the mechanism itself, and its technical complexity, as well as a formal analysis of its guaranteed latency by proving its relation to a token-bucket based ATS. Further, two extensions are discussed, and an evaluation shows the applicability of ACDS by comparing its jitter to ATS in a frame-level simulation.}, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes and Götz, Franz-Josef and Chen, Feng and Schmitt, Jürgen}, booktitle = {2022 IFIP Networking Conference (IFIP Networking)}, keywords = {kosinu5}, month = 6, title = {Constant Delay Switching: Asynchronous Traffic Shaping with Jitter Control}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-15 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %A Götz, Franz-Josef %A Chen, Feng %A Schmitt, Jürgen %B 2022 IFIP Networking Conference (IFIP Networking) %D 2022 %T Constant Delay Switching: Asynchronous Traffic Shaping with Jitter Control %X Recent developments in the Time Sensitive Networking (TSN) group have put forth a number of mechanisms to improve deterministic latency in layer 2 switches. Their shaping approaches differ with respect to prerequisites, flexibility, maximum latency, and latency variation (jitter). Asynchronous solutions provide flexibility in dynamic scenarios, but Credit-Based Shaping (CBS) and Asynchronous Traffic Shaping (ATS) come with a high latency variance, as the minimum latency is not affected by them. Some applications in industrial and automotive use cases require low jitter while trying to avoid a dependency on time synchronization, and even TSN's redundancy mechanism benefits from a lower latency variance. This work is bridging the gap between low-jitter transmission requirements and asynchronous shaping mechanisms. In this paper, the application of a stateless Asynchronous Constant Delay Shaper (ACDS) is discussed. It collects the queuing duration from the previous bridge to delay each frame for the remaining time such that a constant per-hop delay for each frame is achieved. The discussion includes the prerequisites, the mechanism itself, and its technical complexity, as well as a formal analysis of its guaranteed latency by proving its relation to a token-bucket based ATS. Further, two extensions are discussed, and an evaluation shows the applicability of ACDS by comparing its jitter to ATS in a frame-level simulation.
• Affordable Measurement Setups for Networking Device Latency with Sub-Microsecond Accuracy. Grigorjew, Alexej; Diederich, Philip; Hoßfeld, Tobias; Kellerer, Wolfgang. In WueWoWAS’22 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks. 2022.
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  This document presents a networking latency measurement setup that focuses on affordability and universal applicability, and can provide sub-microsecond accuracy. It explains the prerequisites, hardware choices, and considerations to respect during measurement. In addition, it discusses the necessity for exhaustive latency measurements when dealing with high availability and low latency requirements. Preliminary results show that the accuracy is within 0.02 microseconds when used with the Intel I350-T2 network adapter.

  @inproceedings{info3-inproceedings-2022-14, abstract = {This document presents a networking latency measurement setup that focuses on affordability and universal applicability, and can provide sub-microsecond accuracy. It explains the prerequisites, hardware choices, and considerations to respect during measurement. In addition, it discusses the necessity for exhaustive latency measurements when dealing with high availability and low latency requirements. Preliminary results show that the accuracy is within 0.02 microseconds when used with the Intel I350-T2 network adapter.}, author = {Grigorjew, Alexej and Diederich, Philip and Hoßfeld, Tobias and Kellerer, Wolfgang}, booktitle = {WueWoWAS'22 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks}, keywords = {appaware2}, month = 7, title = {Affordable Measurement Setups for Networking Device Latency with Sub-Microsecond Accuracy}, year = 2022 }

  %0 Conference Paper %1 info3-inproceedings-2022-14 %A Grigorjew, Alexej %A Diederich, Philip %A Hoßfeld, Tobias %A Kellerer, Wolfgang %B WueWoWAS'22 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks %D 2022 %T Affordable Measurement Setups for Networking Device Latency with Sub-Microsecond Accuracy %X This document presents a networking latency measurement setup that focuses on affordability and universal applicability, and can provide sub-microsecond accuracy. It explains the prerequisites, hardware choices, and considerations to respect during measurement. In addition, it discusses the necessity for exhaustive latency measurements when dealing with high availability and low latency requirements. Preliminary results show that the accuracy is within 0.02 microseconds when used with the Intel I350-T2 network adapter.
• An Introduction to Online Video Game QoS and QoE Influencing Factors. Metzger, Florian; Geißler, Stefan; Grigorjew, Alexej; Loh, Frank; Moldovan, Christian; Seufert, Michael; Hoßfeld, Tobias. In IEEE Communications Surveys & Tutorials. 2022.
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  Online video games and cloud gaming are rapidly growing in pervasiveness. Their resource demands can put significant stress on the global communication infrastructure. And network conditions are amongst the chief factors that influence one's enjoyment while playing games. This makes it imperative for video games to be considered for network dimensioning, server placement or protocol development. For that reason, in this work we provide an introduction to the technical aspects of video games in general and of their network aspects in particular. This understanding forms the basis for a rich taxonomy of factors that influence and provide context to a video game's Quality of Service (QoS) and Quality of Experience (QoE). The taxonomy covers influence factors from all aspects involved in a video game, from the subjective player and game influence factors to the system and networking influence factors. Finally, this work gives an overview of conducted and ongoing research as well as future research opportunities while taking into account lessons learned from past approaches.

  @article{info3-article-2022-16, abstract = {Online video games and cloud gaming are rapidly growing in pervasiveness. Their resource demands can put significant stress on the global communication infrastructure. And network conditions are amongst the chief factors that influence one's enjoyment while playing games. This makes it imperative for video games to be considered for network dimensioning, server placement or protocol development. For that reason, in this work we provide an introduction to the technical aspects of video games in general and of their network aspects in particular. This understanding forms the basis for a rich taxonomy of factors that influence and provide context to a video game's Quality of Service (QoS) and Quality of Experience (QoE). The taxonomy covers influence factors from all aspects involved in a video game, from the subjective player and game influence factors to the system and networking influence factors. Finally, this work gives an overview of conducted and ongoing research as well as future research opportunities while taking into account lessons learned from past approaches.}, author = {Metzger, Florian and Geißler, Stefan and Grigorjew, Alexej and Loh, Frank and Moldovan, Christian and Seufert, Michael and Hoßfeld, Tobias}, journal = {IEEE Communications Surveys & Tutorials}, keywords = {sys:hidden:article}, month = 5, title = {An Introduction to Online Video Game QoS and QoE Influencing Factors}, year = 2022 }

  %0 Journal Article %1 info3-article-2022-16 %A Metzger, Florian %A Geißler, Stefan %A Grigorjew, Alexej %A Loh, Frank %A Moldovan, Christian %A Seufert, Michael %A Hoßfeld, Tobias %D 2022 %J IEEE Communications Surveys & Tutorials %T An Introduction to Online Video Game QoS and QoE Influencing Factors %X Online video games and cloud gaming are rapidly growing in pervasiveness. Their resource demands can put significant stress on the global communication infrastructure. And network conditions are amongst the chief factors that influence one's enjoyment while playing games. This makes it imperative for video games to be considered for network dimensioning, server placement or protocol development. For that reason, in this work we provide an introduction to the technical aspects of video games in general and of their network aspects in particular. This understanding forms the basis for a rich taxonomy of factors that influence and provide context to a video game's Quality of Service (QoS) and Quality of Experience (QoE). The taxonomy covers influence factors from all aspects involved in a video game, from the subjective player and game influence factors to the system and networking influence factors. Finally, this work gives an overview of conducted and ongoing research as well as future research opportunities while taking into account lessons learned from past approaches.

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

  @inproceedings{info3-inproceedings-2021-7, abstract = {Motivated by new use cases such as industrial automation and in-vehicle communication, Time-Sensitive Networking is further improving the layer 2 standards for real-time communication in Ethernet networks. As periodic traffic is a common requirement in such scenarios, the Time Aware Shaper (TAS) is a highly popular mechanism that allows the realization of real-time guarantees in synchronized networks. Most applications in literature suggest to configure the TAS for full stream isolation such that the lowest delays can be achieved. However, this ``zero-queuing'' strategy requires a high amount of computational resources and time, as the configuration of the gate control lists of each port is a complex task, which is not suitable for scenarios with dynamically changing requirements. This paper presents a novel approach with shared time windows. In combination with stream reservation techniques that are commonly applied for asynchronous mechanisms, the network is able to accept new streams during operation without complex reconfiguration, while still benefiting from some degree of isolation compared to conventional asynchronous shapers. The evaluation shows that, given the right circumstances, the number of accepted real-time streams can be improved significantly.}, author = {Grigorjew, Alexej and Gray, Nicholas and Hoßfeld, Tobias}, booktitle = {2nd International Workshop on Time-Sensitive and Deterministic Networking (TENSOR)}, keywords = {ngn}, month = 6, title = {Dynamic Real-Time Stream Reservation with TAS and Shared Time Windows}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-7 %A Grigorjew, Alexej %A Gray, Nicholas %A Hoßfeld, Tobias %B 2nd International Workshop on Time-Sensitive and Deterministic Networking (TENSOR) %D 2021 %T Dynamic Real-Time Stream Reservation with TAS and Shared Time Windows %X Motivated by new use cases such as industrial automation and in-vehicle communication, Time-Sensitive Networking is further improving the layer~2 standards for real-time communication in Ethernet networks. As periodic traffic is a common requirement in such scenarios, the Time Aware Shaper (TAS) is a highly popular mechanism that allows the realization of real-time guarantees in synchronized networks. Most applications in literature suggest to configure the TAS for full stream isolation such that the lowest delays can be achieved. However, this ``zero-queuing'' strategy requires a high amount of computational resources and time, as the configuration of the gate control lists of each port is a complex task, which is not suitable for scenarios with dynamically changing requirements. This paper presents a novel approach with shared time windows. In combination with stream reservation techniques that are commonly applied for asynchronous mechanisms, the network is able to accept new streams during operation without complex reconfiguration, while still benefiting from some degree of isolation compared to conventional asynchronous shapers. The evaluation shows that, given the right circumstances, the number of accepted real-time streams can be improved significantly.
• Distributed Implementation of Deterministic Networking in Existing Non-TSN Ethernet Switches. Grigorjew, Alexej; Baier, Christian; Metzger, Florian; Hoßfeld, Tobias. In Workshop on Time-sensitive and Deterministic Networking (TsDN). 2021.
  • [ Abstract ]
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  Deterministic networking is quickly gaining importance, as several domains previously dominated by bus systems are now switching to Ethernet. While standardization efforts, especially from the Time-Sensitive Networking (TSN) group, are ongoing, practical deployments are still far off until configuration guidelines and resource management are able to use these tools to their full potential. As an alternative, this work presents a working implementation of bounded latency with an off-the-shelf non-TSN Ethernet switch. The solution is based on a distributed reservation protocol and admission control. It proves that bounded latency is already possible with simple priority-based transmission, and it provides valuable insights for the development and operation of future real-time networking solutions.

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

  %0 Conference Paper %1 info3-inproceedings-2021-6 %A Grigorjew, Alexej %A Baier, Christian %A Metzger, Florian %A Hoßfeld, Tobias %B Workshop on Time-sensitive and Deterministic Networking (TsDN) %D 2021 %T Distributed Implementation of Deterministic Networking in Existing Non-TSN Ethernet Switches %X Deterministic networking is quickly gaining importance, as several domains previously dominated by bus systems are now switching to Ethernet. While standardization efforts, especially from the Time-Sensitive Networking (TSN) group, are ongoing, practical deployments are still far off until configuration guidelines and resource management are able to use these tools to their full potential. As an alternative, this work presents a working implementation of bounded latency with an off-the-shelf non-TSN Ethernet switch. The solution is based on a distributed reservation protocol and admission control. It proves that bounded latency is already possible with simple priority-based transmission, and it provides valuable insights for the development and operation of future real-time networking solutions.
• ML-Assisted Latency Assignments in Time-Sensitive Networking. Grigorjew, Alexej; Seufert, Michael; Wehner, Nikolas; Hofmann, Jan; Hoßfeld, Tobias. In IFIP/IEEE International Symposium on Integrated Network Management (IM 2021). Bordeaux, France (Virtual Conference), 2021.
  • [ Abstract ]
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  Recent developments in industrial automation and invehicle communication have raised the requirements of real-time networking. Bus systems that were traditionally deployed in these fields cannot provide sufficient bandwidth and are now shifting towards Ethernet for their real-time communication needs. In this field, standardization efforts from the IEEE and the IETF have developed new data plane mechanisms such as shapers and schedulers, as well as control plane mechanisms such as reservation protocols to support their new requirements. However, their implementation and their optimal configuration remain an important factor for their efficiency. This work presents a machine learning framework that takes on the configuration task. Four different models are trained for the configuration of per-hop latency guarantees in a distributed resource reservation process and compared with respect to their real-time traffic capacity. The evaluation shows that all models provide good configurations for the provided scenarios, but more importantly, they represent a first step for a semi-automated configuration of parameters in Time-Sensitive Networking.

  @inproceedings{info3-inproceedings-2021-2, abstract = {Recent developments in industrial automation and invehicle communication have raised the requirements of real-time networking. Bus systems that were traditionally deployed in these fields cannot provide sufficient bandwidth and are now shifting towards Ethernet for their real-time communication needs. In this field, standardization efforts from the IEEE and the IETF have developed new data plane mechanisms such as shapers and schedulers, as well as control plane mechanisms such as reservation protocols to support their new requirements. However, their implementation and their optimal configuration remain an important factor for their efficiency. This work presents a machine learning framework that takes on the configuration task. Four different models are trained for the configuration of per-hop latency guarantees in a distributed resource reservation process and compared with respect to their real-time traffic capacity. The evaluation shows that all models provide good configurations for the provided scenarios, but more importantly, they represent a first step for a semi-automated configuration of parameters in Time-Sensitive Networking.}, address = {Bordeaux, France (Virtual Conference)}, author = {Grigorjew, Alexej and Seufert, Michael and Wehner, Nikolas and Hofmann, Jan and Hoßfeld, Tobias}, booktitle = {IFIP/IEEE International Symposium on Integrated Network Management (IM 2021)}, keywords = {kikdin}, month = 5, title = {ML-Assisted Latency Assignments in Time-Sensitive Networking}, year = 2021 }

  %0 Conference Paper %1 info3-inproceedings-2021-2 %A Grigorjew, Alexej %A Seufert, Michael %A Wehner, Nikolas %A Hofmann, Jan %A Hoßfeld, Tobias %B IFIP/IEEE International Symposium on Integrated Network Management (IM 2021) %C Bordeaux, France (Virtual Conference) %D 2021 %T ML-Assisted Latency Assignments in Time-Sensitive Networking %X Recent developments in industrial automation and invehicle communication have raised the requirements of real-time networking. Bus systems that were traditionally deployed in these fields cannot provide sufficient bandwidth and are now shifting towards Ethernet for their real-time communication needs. In this field, standardization efforts from the IEEE and the IETF have developed new data plane mechanisms such as shapers and schedulers, as well as control plane mechanisms such as reservation protocols to support their new requirements. However, their implementation and their optimal configuration remain an important factor for their efficiency. This work presents a machine learning framework that takes on the configuration task. Four different models are trained for the configuration of per-hop latency guarantees in a distributed resource reservation process and compared with respect to their real-time traffic capacity. The evaluation shows that all models provide good configurations for the provided scenarios, but more importantly, they represent a first step for a semi-automated configuration of parameters in Time-Sensitive Networking.

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

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

  %0 Conference Paper %1 info3-inproceedings-2020-17 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %A Götz, Franz-Josef %A Chen, Feng %A Schmitt, Jürgen %B 11th International Conference on Network of the Future (NoF) %D 2020 %T Bounded Latency with Bridge-Local Stream Reservation and Strict Priority Queuing %X Bridge-local latency computation is often regarded with caution, while new shaping mechanisms and timed gates are developed to achieve deterministic guarantees. However, these new concepts require additional hardware support in the forwarding devices, and many of them are based on assumptions of central control and network-wide information being available. This document presents a per-hop latency bound for individual streams in a class-based network that applies the IEEE 802.1Q strict priority transmission selection algorithm. It does not rely on shaping or timed gates and uses the accumulated latency fields during the reservation process to provide upper bounds with bridge-local information. The presented delay bound is proven formally and then evaluated with respect to its accuracy. It shows that deterministic latency with priority queuing is indeed feasible, and it indicates the required information that must be provided during resource reservation, e.g., to protocols developed in IEEE 802.1Qdd.
• Poster: Per-Hop Bridge-Local Latency Bounds with Strict Priority Transmission Selection. Grigorjew, Alexej; Metzger, Florian; Hoßfeld, Tobias; Specht, Johannes; Götz, Franz-Josef; Chen, Feng; Schmitt, Jürgen. In IFIP Networking Conference. 2020.
  • [ Abstract ]
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  This work presents a proven per-hop latency bound for real-time networks with admission control that does not rely on shaping or timed gates. It can be applied in a distributed control plane using only bridge-local information, making it an ideal candidate for brownfield real-time network installations. A brief comparison with Asynchronous Traffic Shaping (ATS) shows that the achieved network utilization is comparable to that of ATS in some scenarios, while it only lags behind in scenarios with accumulating bursts where re-shaping could actually reduce the interference of the observed streams.

  @inproceedings{info3-inproceedings-2020-16, abstract = {This work presents a proven per-hop latency bound for real-time networks with admission control that does not rely on shaping or timed gates. It can be applied in a distributed control plane using only bridge-local information, making it an ideal candidate for brownfield real-time network installations. A brief comparison with Asynchronous Traffic Shaping (ATS) shows that the achieved network utilization is comparable to that of ATS in some scenarios, while it only lags behind in scenarios with accumulating bursts where re-shaping could actually reduce the interference of the observed streams.}, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes and Götz, Franz-Josef and Chen, Feng and Schmitt, Jürgen}, booktitle = {IFIP Networking Conference}, keywords = {ats-performance}, month = 6, title = {Poster: Per-Hop Bridge-Local Latency Bounds with Strict Priority Transmission Selection}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-16 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %A Götz, Franz-Josef %A Chen, Feng %A Schmitt, Jürgen %B IFIP Networking Conference %D 2020 %T Poster: Per-Hop Bridge-Local Latency Bounds with Strict Priority Transmission Selection %X This work presents a proven per-hop latency bound for real-time networks with admission control that does not rely on shaping or timed gates. It can be applied in a distributed control plane using only bridge-local information, making it an ideal candidate for brownfield real-time network installations. A brief comparison with Asynchronous Traffic Shaping (ATS) shows that the achieved network utilization is comparable to that of ATS in some scenarios, while it only lags behind in scenarios with accumulating bursts where re-shaping could actually reduce the interference of the observed streams.

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

  @inproceedings{info3-inproceedings-2019-16, abstract = {As the requirements of real-time networking in- crease, the IEEE Time-Sensitive Networking (TSN) task group is working on new standards for high bandwidth and low latency Ethernet switching. In particular, the upcoming P802.1Qcr standard features Asynchronous Traffic Shaping (ATS), which is a promising approach for real-time networks with high dynamics and critical safety requirements. Additionally, parallel concepts such as frame preemption can be used to reduce delays even further. This work presents a discrete event simulation framework that can analyze the performance of these concepts. It implements frame preemption and multiple shaping algorithms, while recording latency and queue utilization statistics at the switches. In addition, an evaluation of a linear topology with four switches is performed under high link utilization, which demonstrates the benefit of the above mechanisms compared to regular Ethernet switching.}, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes}, booktitle = {Workshop for Advanced Communication Networks for Industrial Applications}, keywords = {fullstack}, month = 3, title = {A Simulation of Asynchronous Traffic Shapers in Switched Ethernet Networks}, year = 2019 }

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

• 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
• 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

• 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