Dr. Florian Metzger

• 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 = {05}, 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.
• LoRaPlan: A Software to Evaluate Gateway Placement in LoRaWAN. Loh, Frank; Mehling, Noah; Metzger, Florian; Hoßfeld, Tobias. In 17th International Conference on Network and Service Management. 2021.
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  Long Range Wide Area Network (LoRaWAN) is one of the fastest growing Internet of Things (IoT) access network solutions. One major challenge in current LoRaWAN planning is message collision due to the random channel access. To study the collision behavior in LoRaWAN, we present LoRaPlan in this demonstration. LoRaPlan is a software to evaluate gateway placement decisions by studying the collision probability. Therefore, sensor and gateway locations can be imported to create a LoRaWAN. Furthermore, existing networks can be extended by additional gateways. Based on this setup, network coverage, network quality with regard to the number of sensors a single gateway has to manage, and also transmission quality and collision probabilities can be studied. In this demonstration, first the process of network creation with gateway and sensor import and additional manual gateway placement in LoRaPlan is presented. Different adjustable parameters are shown and the influence on network coverage and collision probability is discussed. At the end of this demonstration, it is possible for the audience to place their own gateways and evaluate own placements by means of collision probability and the coverage.

  @article{info3-article-2021-11, abstract = {Long Range Wide Area Network (LoRaWAN) is one of the fastest growing Internet of Things (IoT) access network solutions. One major challenge in current LoRaWAN planning is message collision due to the random channel access. To study the collision behavior in LoRaWAN, we present LoRaPlan in this demonstration. LoRaPlan is a software to evaluate gateway placement decisions by studying the collision probability. Therefore, sensor and gateway locations can be imported to create a LoRaWAN. Furthermore, existing networks can be extended by additional gateways. Based on this setup, network coverage, network quality with regard to the number of sensors a single gateway has to manage, and also transmission quality and collision probabilities can be studied. In this demonstration, first the process of network creation with gateway and sensor import and additional manual gateway placement in LoRaPlan is presented. Different adjustable parameters are shown and the influence on network coverage and collision probability is discussed. At the end of this demonstration, it is possible for the audience to place their own gateways and evaluate own placements by means of collision probability and the coverage.}, author = {Loh, Frank and Mehling, Noah and Metzger, Florian and Hoßfeld, Tobias}, journal = {17th International Conference on Network and Service Management}, keywords = {sys:hidden:article}, month = 10, title = {LoRaPlan: A Software to Evaluate Gateway Placement in LoRaWAN}, year = 2021 }

  %0 Journal Article %1 info3-article-2021-11 %A Loh, Frank %A Mehling, Noah %A Metzger, Florian %A Hoßfeld, Tobias %D 2021 %J 17th International Conference on Network and Service Management %T LoRaPlan: A Software to Evaluate Gateway Placement in LoRaWAN %X Long Range Wide Area Network (LoRaWAN) is one of the fastest growing Internet of Things (IoT) access network solutions. One major challenge in current LoRaWAN planning is message collision due to the random channel access. To study the collision behavior in LoRaWAN, we present LoRaPlan in this demonstration. LoRaPlan is a software to evaluate gateway placement decisions by studying the collision probability. Therefore, sensor and gateway locations can be imported to create a LoRaWAN. Furthermore, existing networks can be extended by additional gateways. Based on this setup, network coverage, network quality with regard to the number of sensors a single gateway has to manage, and also transmission quality and collision probabilities can be studied. In this demonstration, first the process of network creation with gateway and sensor import and additional manual gateway placement in LoRaPlan is presented. Different adjustable parameters are shown and the influence on network coverage and collision probability is discussed. At the end of this demonstration, it is possible for the audience to place their own gateways and evaluate own placements by means of collision probability and the coverage.
• IJNM Special Issue - Editorial - QoE-centric Analysis and Management of Communication Networks. Wamser, Florian; Alay, Özgü; Metzger, Florian; Valentin, Stefan. In International Journal of Network Management, Special Issue: QoE-centric Analysis and Management of Communication Networks. 2020.
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  The heterogeneity and variability of Internet applications has increased considerably in recent years. Applications such as video streaming are responsible for a large part of data traffic on the Internet. Internet telephony and video conferencing systems have become part of our daily lives. At the same time, the Internet of Things is striving to exceed previous expectations regarding the number of devices. Furthermore, the proliferation of video games, virtual reality applications, and 360° video applications is increasing. All this leads to specific but different requirements from applications to frameworks, service platforms, and networks. For each service, users desire special service criteria, such as smooth interactivity, fast downloads, high availability, or extensive content. Such requirements can usually be summarized under the term Quality of Experience, i.e., the overall satisfaction of a user with the system cur- rently in use. In the age of big data and dynamic networks, Quality of Experience is still looking for its place, and good solutions are in high demand. This Special Issue addresses the latest advances and challenges in analysis, design, modeling, measurement, and performance evaluation of Quality of Experience and Quality of Experience-oriented metrics and management.

  @article{info3-article-2020-1, abstract = {The heterogeneity and variability of Internet applications has increased considerably in recent years. Applications such as video streaming are responsible for a large part of data traffic on the Internet. Internet telephony and video conferencing systems have become part of our daily lives. At the same time, the Internet of Things is striving to exceed previous expectations regarding the number of devices. Furthermore, the proliferation of video games, virtual reality applications, and 360° video applications is increasing. All this leads to specific but different requirements from applications to frameworks, service platforms, and networks. For each service, users desire special service criteria, such as smooth interactivity, fast downloads, high availability, or extensive content. Such requirements can usually be summarized under the term Quality of Experience, i.e., the overall satisfaction of a user with the system cur- rently in use. In the age of big data and dynamic networks, Quality of Experience is still looking for its place, and good solutions are in high demand. This Special Issue addresses the latest advances and challenges in analysis, design, modeling, measurement, and performance evaluation of Quality of Experience and Quality of Experience-oriented metrics and management.}, author = {Wamser, Florian and Alay, Özgü and Metzger, Florian and Valentin, Stefan}, journal = {International Journal of Network Management}, keywords = {can}, month = {03}, title = {IJNM Special Issue - Editorial - QoE-centric Analysis and Management of Communication Networks}, volume = {Special Issue: QoE-centric Analysis and Management of Communication Networks}, year = 2020 }

  %0 Journal Article %1 info3-article-2020-1 %A Wamser, Florian %A Alay, Özgü %A Metzger, Florian %A Valentin, Stefan %D 2020 %J International Journal of Network Management %T IJNM Special Issue - Editorial - QoE-centric Analysis and Management of Communication Networks %V Special Issue: QoE-centric Analysis and Management of Communication Networks %X The heterogeneity and variability of Internet applications has increased considerably in recent years. Applications such as video streaming are responsible for a large part of data traffic on the Internet. Internet telephony and video conferencing systems have become part of our daily lives. At the same time, the Internet of Things is striving to exceed previous expectations regarding the number of devices. Furthermore, the proliferation of video games, virtual reality applications, and 360° video applications is increasing. All this leads to specific but different requirements from applications to frameworks, service platforms, and networks. For each service, users desire special service criteria, such as smooth interactivity, fast downloads, high availability, or extensive content. Such requirements can usually be summarized under the term Quality of Experience, i.e., the overall satisfaction of a user with the system cur- rently in use. In the age of big data and dynamic networks, Quality of Experience is still looking for its place, and good solutions are in high demand. This Special Issue addresses the latest advances and challenges in analysis, design, modeling, measurement, and performance evaluation of Quality of Experience and Quality of Experience-oriented metrics and management.
• Modeling of Aggregated IoT Traffic and Its Application to an IoT Cloud. Metzger, Florian; Hoßfeld, Tobias; Bauer, André; Kounev, Samuel; Heegaard, Poul E. In Proceedings of the IEEE, 107(4), pp. 679–694. 2019.
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  As the Internet of Things (IoT) continues to gain traction in telecommunication networks, a very large number of devices are expected to be connected and used in the near future. In order to appropriately plan and dimension the network, as well as the back-end cloud systems and the resulting signaling load, traffic models are employed. These models are designed to accurately capture and predict the properties of IoT traffic in a concise manner. To achieve this, Poisson process approximations, based on the Palm–Khintchine theorem, have often been used in the past. Due to the scale (and the difference in scales in various IoT networks) of the modeled systems, the fidelity of this approximation is crucial, as, in practice, it is very challenging to accurately measure or simulate large-scale IoT deployments. The main goal of this paper is to understand the level of accuracy of the Poisson approximation model. To this end, we first survey both common IoT network properties and network scales as well as traffic types. Second, we explain and discuss the Palm–Khintiche theorem, how it is applied to the problem, and which inaccuracies can occur when using it. Based on this, we derive guidelines as to when a Poisson process can be assumed for aggregated periodic IoT traffic. Finally, we evaluate our approach in the context of an IoT cloud scaler use case.

  @article{info3-article-2019-3, abstract = {As the Internet of Things (IoT) continues to gain traction in telecommunication networks, a very large number of devices are expected to be connected and used in the near future. In order to appropriately plan and dimension the network, as well as the back-end cloud systems and the resulting signaling load, traffic models are employed. These models are designed to accurately capture and predict the properties of IoT traffic in a concise manner. To achieve this, Poisson process approximations, based on the Palm–Khintchine theorem, have often been used in the past. Due to the scale (and the difference in scales in various IoT networks) of the modeled systems, the fidelity of this approximation is crucial, as, in practice, it is very challenging to accurately measure or simulate large-scale IoT deployments. The main goal of this paper is to understand the level of accuracy of the Poisson approximation model. To this end, we first survey both common IoT network properties and network scales as well as traffic types. Second, we explain and discuss the Palm–Khintiche theorem, how it is applied to the problem, and which inaccuracies can occur when using it. Based on this, we derive guidelines as to when a Poisson process can be assumed for aggregated periodic IoT traffic. Finally, we evaluate our approach in the context of an IoT cloud scaler use case.}, author = {Metzger, Florian and Hoßfeld, Tobias and Bauer, André and Kounev, Samuel and Heegaard, Poul E.}, journal = {Proceedings of the IEEE}, keywords = {doi:10.1109/JPROC.2019.2901578}, month = {04}, number = 4, pages = {679-694}, title = {Modeling of Aggregated IoT Traffic and Its Application to an IoT Cloud}, volume = 107, year = 2019 }

  %0 Journal Article %1 info3-article-2019-3 %A Metzger, Florian %A Hoßfeld, Tobias %A Bauer, André %A Kounev, Samuel %A Heegaard, Poul E. %D 2019 %J Proceedings of the IEEE %N 4 %P 679-694 %T Modeling of Aggregated IoT Traffic and Its Application to an IoT Cloud %V 107 %X As the Internet of Things (IoT) continues to gain traction in telecommunication networks, a very large number of devices are expected to be connected and used in the near future. In order to appropriately plan and dimension the network, as well as the back-end cloud systems and the resulting signaling load, traffic models are employed. These models are designed to accurately capture and predict the properties of IoT traffic in a concise manner. To achieve this, Poisson process approximations, based on the Palm–Khintchine theorem, have often been used in the past. Due to the scale (and the difference in scales in various IoT networks) of the modeled systems, the fidelity of this approximation is crucial, as, in practice, it is very challenging to accurately measure or simulate large-scale IoT deployments. The main goal of this paper is to understand the level of accuracy of the Poisson approximation model. To this end, we first survey both common IoT network properties and network scales as well as traffic types. Second, we explain and discuss the Palm–Khintiche theorem, how it is applied to the problem, and which inaccuracies can occur when using it. Based on this, we derive guidelines as to when a Poisson process can be assumed for aggregated periodic IoT traffic. Finally, we evaluate our approach in the context of an IoT cloud scaler use case.
• TCP video streaming and mobile networks: Not a love story, but better with context. Metzger, Florian; Liotou, Eirini; Moldovan, Christian; Hoßfeld, Tobias. In Computer Networks, 109, pp. 246–256. 2016.
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  @article{info3-article-2016-12, author = {Metzger, Florian and Liotou, Eirini and Moldovan, Christian and Hoßfeld, Tobias}, journal = {Computer Networks}, keywords = {sys:hidden:article}, pages = {246–256}, title = {TCP video streaming and mobile networks: Not a love story, but better with context}, volume = 109, year = 2016 }

  %0 Journal Article %1 info3-article-2016-12 %A Metzger, Florian %A Liotou, Eirini %A Moldovan, Christian %A Hoßfeld, Tobias %D 2016 %J Computer Networks %P 246--256 %T TCP video streaming and mobile networks: Not a love story, but better with context %V 109
• QoE for Cloud Gaming. Hoßfeld, Tobias; Metzger, Florian; Jarschel, Michael. In IEEE Communications Society E-Letter. 2015.
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  Cloud Gaming combines the successful concepts of Cloud Computing and Online Gaming. It provides the entire game experience to the users by processing the game in the cloud and streaming the contents to the player. The player is no longer dependent on a specific type or quality of gaming hardware, but is able to use common devices. However, at the same time the end device needs a broadband internet connection and the ability to display a video stream properly. While this may reduce hardware costs for users and increase the revenue for developers by leaving out the retail chain, it also raises new challenges for Quality of Service (QoS) in terms of bandwidth and latency for the underlying network. In particular, there is a strong interest in the player’s Quality of Experience (QoE) by the involved stakeholders, ie, the game providers and the network operators. Given similar pricing schemes, players are likely to be influenced by expected and experienced quality. Thus, a provider is interested to understand QoE and to react on QoE problems by managing or adapting the service. There is also a strong academic interest, since QoE for cloud gaming as well as managing QoE for cloud gaming addresses a multitude of fascinating challenges in QoE. One might think that the topic of online video games is equally popular in research, but efforts are often solely focused on cloud gaming and its subjective QoE through user studies. Compared to plain video streaming, the inner properties of video games are not that straight-forward to observe from the outside. But to conduct proper measurements, it is essential to understand them.

  @article{info3-article-2015-9, abstract = {Cloud Gaming combines the successful concepts of Cloud Computing and Online Gaming. It provides the entire game experience to the users by processing the game in the cloud and streaming the contents to the player. The player is no longer dependent on a specific type or quality of gaming hardware, but is able to use common devices. However, at the same time the end device needs a broadband internet connection and the ability to display a video stream properly. While this may reduce hardware costs for users and increase the revenue for developers by leaving out the retail chain, it also raises new challenges for Quality of Service (QoS) in terms of bandwidth and latency for the underlying network. In particular, there is a strong interest in the player’s Quality of Experience (QoE) by the involved stakeholders, ie, the game providers and the network operators. Given similar pricing schemes, players are likely to be influenced by expected and experienced quality. Thus, a provider is interested to understand QoE and to react on QoE problems by managing or adapting the service. There is also a strong academic interest, since QoE for cloud gaming as well as managing QoE for cloud gaming addresses a multitude of fascinating challenges in QoE. One might think that the topic of online video games is equally popular in research, but efforts are often solely focused on cloud gaming and its subjective QoE through user studies. Compared to plain video streaming, the inner properties of video games are not that straight-forward to observe from the outside. But to conduct proper measurements, it is essential to understand them.}, author = {Hoßfeld, Tobias and Metzger, Florian and Jarschel, Michael}, journal = {IEEE Communications Society E-Letter}, keywords = {sys:hidden:article}, month = 11, title = {QoE for Cloud Gaming}, year = 2015 }

  %0 Journal Article %1 info3-article-2015-9 %A Hoßfeld, Tobias %A Metzger, Florian %A Jarschel, Michael %D 2015 %J IEEE Communications Society E-Letter %T QoE for Cloud Gaming %X Cloud Gaming combines the successful concepts of Cloud Computing and Online Gaming. It provides the entire game experience to the users by processing the game in the cloud and streaming the contents to the player. The player is no longer dependent on a specific type or quality of gaming hardware, but is able to use common devices. However, at the same time the end device needs a broadband internet connection and the ability to display a video stream properly. While this may reduce hardware costs for users and increase the revenue for developers by leaving out the retail chain, it also raises new challenges for Quality of Service (QoS) in terms of bandwidth and latency for the underlying network. In particular, there is a strong interest in the player’s Quality of Experience (QoE) by the involved stakeholders, ie, the game providers and the network operators. Given similar pricing schemes, players are likely to be influenced by expected and experienced quality. Thus, a provider is interested to understand QoE and to react on QoE problems by managing or adapting the service. There is also a strong academic interest, since QoE for cloud gaming as well as managing QoE for cloud gaming addresses a multitude of fascinating challenges in QoE. One might think that the topic of online video games is equally popular in research, but efforts are often solely focused on cloud gaming and its subjective QoE through user studies. Compared to plain video streaming, the inner properties of video games are not that straight-forward to observe from the outside. But to conduct proper measurements, it is essential to understand them.
• Exploratory Analysis of a GGSN’s PDP Context Signaling Load. Metzger, Florian; Rafetseder, Albert; Romirer-Maierhofer, Peter; Tutschku, Kurt. In Journal of Computer Networks and Communications. 2014.
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  @article{info3-article-2014-12, author = {Metzger, Florian and Rafetseder, Albert and Romirer-Maierhofer, Peter and Tutschku, Kurt}, journal = {Journal of Computer Networks and Communications}, keywords = {sys:hidden:article}, month = {02}, title = {Exploratory Analysis of a GGSN’s PDP Context Signaling Load}, year = 2014 }

  %0 Journal Article %1 info3-article-2014-12 %A Metzger, Florian %A Rafetseder, Albert %A Romirer-Maierhofer, Peter %A Tutschku, Kurt %D 2014 %J Journal of Computer Networks and Communications %T Exploratory Analysis of a GGSN’s PDP Context Signaling Load
• Sensorium – A Generic Sensor Framework. Rafetseder, Albert; Metzger, Florian; Pühringer, Lukas; Tutschku, Kurt; Zhuang, Yanyan; Cappos, Justin. In PIK - Praxis der Informationsverarbeitung und Kommunikation, 36(1). 2013.
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  @article{info3-article-2013-14, author = {Rafetseder, Albert and Metzger, Florian and Pühringer, Lukas and Tutschku, Kurt and Zhuang, Yanyan and Cappos, Justin}, journal = {PIK - Praxis der Informationsverarbeitung und Kommunikation}, keywords = {sys:hidden:article}, month = {02}, number = 1, title = {Sensorium – A Generic Sensor Framework}, volume = 36, year = 2013 }

  %0 Journal Article %1 info3-article-2013-14 %A Rafetseder, Albert %A Metzger, Florian %A Pühringer, Lukas %A Tutschku, Kurt %A Zhuang, Yanyan %A Cappos, Justin %D 2013 %J PIK - Praxis der Informationsverarbeitung und Kommunikation %N 1 %T Sensorium – A Generic Sensor Framework %V 36
• On the influence of network impairments on YouTube video streaming. Biernacki, Arkadiusz; Metzger, Florian; Tutschku, Kurt. In Journal of Telecommunications and Information Technology. 2012.
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  Video sharing services like YouTube have become very popular which consequently results in a drastic shift of the Internet traffic statistic. When transmitting video content over packet based networks, stringent quality of service (QoS) constraints must be met in order to provide the comparable level of quality to a traditional broadcast television. However, the packet transmission is influenced by delays and losses of data packets which can have devastating influence on the perceived quality of the video. Therefore, we conducted an experimental evaluation of HTTP based video transmission focusing on how they react to packet delay and loss. Through this analysis we investigated how long video playback is stalled and how often re-buffering events take place. Our analysis revealed threshold levels for the packet delay, packet losses and network throughput which should not be exceeded in order to preserve smooth video transmission.

  @article{info3-article-2012-11, abstract = {Video sharing services like YouTube have become very popular which consequently results in a drastic shift of the Internet traffic statistic. When transmitting video content over packet based networks, stringent quality of service (QoS) constraints must be met in order to provide the comparable level of quality to a traditional broadcast television. However, the packet transmission is influenced by delays and losses of data packets which can have devastating influence on the perceived quality of the video. Therefore, we conducted an experimental evaluation of HTTP based video transmission focusing on how they react to packet delay and loss. Through this analysis we investigated how long video playback is stalled and how often re-buffering events take place. Our analysis revealed threshold levels for the packet delay, packet losses and network throughput which should not be exceeded in order to preserve smooth video transmission.}, author = {Biernacki, Arkadiusz and Metzger, Florian and Tutschku, Kurt}, journal = {Journal of Telecommunications and Information Technology}, keywords = {sys:hidden:article}, title = {On the influence of network impairments on YouTube video streaming}, year = 2012 }

  %0 Journal Article %1 info3-article-2012-11 %A Biernacki, Arkadiusz %A Metzger, Florian %A Tutschku, Kurt %D 2012 %J Journal of Telecommunications and Information Technology %T On the influence of network impairments on YouTube video streaming %X Video sharing services like YouTube have become very popular which consequently results in a drastic shift of the Internet traffic statistic. When transmitting video content over packet based networks, stringent quality of service (QoS) constraints must be met in order to provide the comparable level of quality to a traditional broadcast television. However, the packet transmission is influenced by delays and losses of data packets which can have devastating influence on the perceived quality of the video. Therefore, we conducted an experimental evaluation of HTTP based video transmission focusing on how they react to packet delay and loss. Through this analysis we investigated how long video playback is stalled and how often re-buffering events take place. Our analysis revealed threshold levels for the packet delay, packet losses and network throughput which should not be exceeded in order to preserve smooth video transmission.

• Context Monitoring for Improved System Performance and QoE. Metzger, Florian; Hoßfeld, Tobias; Skorin-Kapov, Lea; Liotou, Eirini; Pocta, Peter; Melvin, Hugh; Siris, Vasilios; Zgank, Andrej; Jarschel, Michael. In Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms, and Tools, I. Ganchev, R. D. van der Mei, H. van den Berg (eds.). Springer International Publishing, 2018.
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  Whereas some application domains show a certain consensus on the role of system factors, human factors, and context factors, QoE management of multimedia systems and services is still faced with the challenge of identifying the key QoE influence factors. In this chapter, we focus on the potential of enhancing QoE management mechanisms by exploiting valuable context information. To get a good grip on the basics we first discuss a general framework for context monitoring and define context information, including technical, usage, social, economic, temporal, and physical factors. We then iterate the opportunities and challenges in involving context in QoE monitoring solutions, as context may be, e.g., hard to ascertain or very situational. The benefits of including context in QoE monitoring and management are demonstrated through use cases involving video flash crowds as well as online and cloud gaming. Finally, we discuss potential technical realizations of context-aware QoE monitoring and management derived based on the SDN paradigm.

  @incollection{info3-incollection-2018-3, abstract = {Whereas some application domains show a certain consensus on the role of system factors, human factors, and context factors, QoE management of multimedia systems and services is still faced with the challenge of identifying the key QoE influence factors. In this chapter, we focus on the potential of enhancing QoE management mechanisms by exploiting valuable context information. To get a good grip on the basics we first discuss a general framework for context monitoring and define context information, including technical, usage, social, economic, temporal, and physical factors. We then iterate the opportunities and challenges in involving context in QoE monitoring solutions, as context may be, e.g., hard to ascertain or very situational. The benefits of including context in QoE monitoring and management are demonstrated through use cases involving video flash crowds as well as online and cloud gaming. Finally, we discuss potential technical realizations of context-aware QoE monitoring and management derived based on the SDN paradigm.}, author = {Metzger, Florian and Hoßfeld, Tobias and Skorin-Kapov, Lea and Liotou, Eirini and Pocta, Peter and Melvin, Hugh and Siris, Vasilios and Zgank, Andrej and Jarschel, Michael}, booktitle = {Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms, and Tools}, editor = {Ganchev, Ivan and van der Mei, R. D. and van den Berg, Hans}, keywords = {ua-net}, month = {05}, publisher = {Springer International Publishing}, title = {Context Monitoring for Improved System Performance and QoE}, year = 2018 }

  %0 Book Section %1 info3-incollection-2018-3 %A Metzger, Florian %A Hoßfeld, Tobias %A Skorin-Kapov, Lea %A Liotou, Eirini %A Pocta, Peter %A Melvin, Hugh %A Siris, Vasilios %A Zgank, Andrej %A Jarschel, Michael %B Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms, and Tools %D 2018 %E Ganchev, Ivan %E van der Mei, R. D. %E van den Berg, Hans %I Springer International Publishing %T Context Monitoring for Improved System Performance and QoE %X Whereas some application domains show a certain consensus on the role of system factors, human factors, and context factors, QoE management of multimedia systems and services is still faced with the challenge of identifying the key QoE influence factors. In this chapter, we focus on the potential of enhancing QoE management mechanisms by exploiting valuable context information. To get a good grip on the basics we first discuss a general framework for context monitoring and define context information, including technical, usage, social, economic, temporal, and physical factors. We then iterate the opportunities and challenges in involving context in QoE monitoring solutions, as context may be, e.g., hard to ascertain or very situational. The benefits of including context in QoE monitoring and management are demonstrated through use cases involving video flash crowds as well as online and cloud gaming. Finally, we discuss potential technical realizations of context-aware QoE monitoring and management derived based on the SDN paradigm.
• The Value of Context-Awareness in Bandwidth-Challenging HTTP Adaptive Streaming Scenarios. Liotou, Eirini; Hoßfeld, Tobias; Moldovan, Christian; Metzger, Florian; Tsolkas, Dimitris; Passas, Nikos. In Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms, and Tools, I. Ganchev, R. D. van der Mei, H. van den Berg (eds.). Springer International Publishing, 2018.
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  • [ EndNote ]
  Video streaming has become an indispensable technology in people’s lives, while its usage keeps constantly increasing. The variability, instability and unpredictability of network conditions pose one of the biggest challenges to video streaming. In this chapter, we analyze HTTP Adaptive Streaming, a technology that relieves these issues by adapting the video reproduction to the current network conditions. Particularly, we study how context awareness can be combined with the adaptive streaming logic to design a proactive client-based video streaming strategy. Our results show that such a context-aware strategy manages to successfully mitigate stallings in light of network connectivity problems, such as an outage. Moreover, we analyze the performance of this strategy by comparing it to the optimal case, as well as by considering situations where the awareness of the context lacks reliability.

  @incollection{info3-incollection-2018-4, abstract = {Video streaming has become an indispensable technology in people’s lives, while its usage keeps constantly increasing. The variability, instability and unpredictability of network conditions pose one of the biggest challenges to video streaming. In this chapter, we analyze HTTP Adaptive Streaming, a technology that relieves these issues by adapting the video reproduction to the current network conditions. Particularly, we study how context awareness can be combined with the adaptive streaming logic to design a proactive client-based video streaming strategy. Our results show that such a context-aware strategy manages to successfully mitigate stallings in light of network connectivity problems, such as an outage. Moreover, we analyze the performance of this strategy by comparing it to the optimal case, as well as by considering situations where the awareness of the context lacks reliability.}, author = {Liotou, Eirini and Hoßfeld, Tobias and Moldovan, Christian and Metzger, Florian and Tsolkas, Dimitris and Passas, Nikos}, booktitle = {Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms, and Tools}, editor = {Ganchev, Ivan and van der Mei, R. D. and van den Berg, Hans}, keywords = {fullstack}, month = {05}, publisher = {Springer International Publishing}, title = {The Value of Context-Awareness in Bandwidth-Challenging HTTP Adaptive Streaming Scenarios}, year = 2018 }

  %0 Book Section %1 info3-incollection-2018-4 %A Liotou, Eirini %A Hoßfeld, Tobias %A Moldovan, Christian %A Metzger, Florian %A Tsolkas, Dimitris %A Passas, Nikos %B Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms, and Tools %D 2018 %E Ganchev, Ivan %E van der Mei, R. D. %E van den Berg, Hans %I Springer International Publishing %T The Value of Context-Awareness in Bandwidth-Challenging HTTP Adaptive Streaming Scenarios %X Video streaming has become an indispensable technology in people’s lives, while its usage keeps constantly increasing. The variability, instability and unpredictability of network conditions pose one of the biggest challenges to video streaming. In this chapter, we analyze HTTP Adaptive Streaming, a technology that relieves these issues by adapting the video reproduction to the current network conditions. Particularly, we study how context awareness can be combined with the adaptive streaming logic to design a proactive client-based video streaming strategy. Our results show that such a context-aware strategy manages to successfully mitigate stallings in light of network connectivity problems, such as an outage. Moreover, we analyze the performance of this strategy by comparing it to the optimal case, as well as by considering situations where the awareness of the context lacks reliability.

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

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

  %0 Conference Paper %1 info3-inproceedings-2022-15 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %A Götz, Franz-Josef %A Chen, Feng %A Schmitt, Jürgen %B 2022 IFIP Networking Conference (IFIP Networking) %D 2022 %T Constant Delay Switching: Asynchronous Traffic Shaping with Jitter Control %X Recent developments in the Time Sensitive Networking (TSN) group have put forth a number of mechanisms to improve deterministic latency in layer 2 switches. Their shaping approaches differ with respect to prerequisites, flexibility, maximum latency, and latency variation (jitter). Asynchronous solutions provide flexibility in dynamic scenarios, but Credit-Based Shaping (CBS) and Asynchronous Traffic Shaping (ATS) come with a high latency variance, as the minimum latency is not affected by them. Some applications in industrial and automotive use cases require low jitter while trying to avoid a dependency on time synchronization, and even TSN's redundancy mechanism benefits from a lower latency variance. This work is bridging the gap between low-jitter transmission requirements and asynchronous shaping mechanisms. In this paper, the application of a stateless Asynchronous Constant Delay Shaper (ACDS) is discussed. It collects the queuing duration from the previous bridge to delay each frame for the remaining time such that a constant per-hop delay for each frame is achieved. The discussion includes the prerequisites, the mechanism itself, and its technical complexity, as well as a formal analysis of its guaranteed latency by proving its relation to a token-bucket based ATS. Further, two extensions are discussed, and an evaluation shows the applicability of ACDS by comparing its jitter to ATS in a frame-level simulation.
• Improving LoRaWAN’s Successful Information Transmission Rate with Redundancy. Loh, Frank; Raffeck, Simon; Metzger, Florian; Hoßfeld, Tobias. In 17th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob). 2021.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  • [ Download ]
  The adaptation of Internet of Things in our everyday life shows different new demands and challenges. One of the fastest growing technologies in this context are Low Power Wide Area Networks with LoRaWAN as one of their most prominent representatives. The promise of this technology is to transmit sensor data over large distances with very little energy consumption. But transmission behavior, and especially overhead and collision probability, must be studied in detail to improve transmission quality and energy consumption due to the random access nature of LoRaWAN. Because of that, this work investigates the LoRaWAN channel capacity by analyzing the transmission overhead, the collision probability, and the data loss. At the end, an energy consumption comparison is done. The contribution is a novel approach based on aggregation and retransmission that shows a decreased data loss of up to 20% compared to the currently used random channel access.

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

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

  %0 Conference Paper %1 info3-inproceedings-2021-13 %A Metzger, Florian %A Stulier, Norman %A Borchert, Kathrin %A Hirth, Matthias %B Proceedings of the 13th International Conference on Quality of Multimedia Experience (QoMEX 2021) %D 2021 %T Relationship Status: It's Complicated. Using APM as a QoE-qualifying Tempo Metric
• Distributed Implementation of Deterministic Networking in Existing Non-TSN Ethernet Switches. Grigorjew, Alexej; Baier, Christian; Metzger, Florian; Hoßfeld, Tobias. In Workshop on Time-sensitive and Deterministic Networking (TsDN). 2021.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Deterministic networking is quickly gaining importance, as several domains previously dominated by bus systems are now switching to Ethernet. While standardization efforts, especially from the Time-Sensitive Networking (TSN) group, are ongoing, practical deployments are still far off until configuration guidelines and resource management are able to use these tools to their full potential. As an alternative, this work presents a working implementation of bounded latency with an off-the-shelf non-TSN Ethernet switch. The solution is based on a distributed reservation protocol and admission control. It proves that bounded latency is already possible with simple priority-based transmission, and it provides valuable insights for the development and operation of future real-time networking solutions.

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

  %0 Conference Paper %1 info3-inproceedings-2021-6 %A Grigorjew, Alexej %A Baier, Christian %A Metzger, Florian %A Hoßfeld, Tobias %B Workshop on Time-sensitive and Deterministic Networking (TsDN) %D 2021 %T Distributed Implementation of Deterministic Networking in Existing Non-TSN Ethernet Switches %X Deterministic networking is quickly gaining importance, as several domains previously dominated by bus systems are now switching to Ethernet. While standardization efforts, especially from the Time-Sensitive Networking (TSN) group, are ongoing, practical deployments are still far off until configuration guidelines and resource management are able to use these tools to their full potential. As an alternative, this work presents a working implementation of bounded latency with an off-the-shelf non-TSN Ethernet switch. The solution is based on a distributed reservation protocol and admission control. It proves that bounded latency is already possible with simple priority-based transmission, and it provides valuable insights for the development and operation of future real-time networking solutions.
• Bounded Latency with Bridge-Local Stream Reservation and Strict Priority Queuing. Grigorjew, Alexej; Metzger, Florian; Hoßfeld, Tobias; Specht, Johannes; Götz, Franz-Josef; Chen, Feng; Schmitt, Jürgen. In 11th International Conference on Network of the Future (NoF). 2020.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Bridge-local latency computation is often regarded with caution, while new shaping mechanisms and timed gates are developed to achieve deterministic guarantees. However, these new concepts require additional hardware support in the forwarding devices, and many of them are based on assumptions of central control and network-wide information being available. This document presents a per-hop latency bound for individual streams in a class-based network that applies the IEEE 802.1Q strict priority transmission selection algorithm. It does not rely on shaping or timed gates and uses the accumulated latency fields during the reservation process to provide upper bounds with bridge-local information. The presented delay bound is proven formally and then evaluated with respect to its accuracy. It shows that deterministic latency with priority queuing is indeed feasible, and it indicates the required information that must be provided during resource reservation, e.g., to protocols developed in IEEE 802.1Qdd.

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

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

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

  %0 Conference Paper %1 info3-inproceedings-2020-16 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %A Götz, Franz-Josef %A Chen, Feng %A Schmitt, Jürgen %B IFIP Networking Conference %D 2020 %T Poster: Per-Hop Bridge-Local Latency Bounds with Strict Priority Transmission Selection %X This work presents a proven per-hop latency bound for real-time networks with admission control that does not rely on shaping or timed gates. It can be applied in a distributed control plane using only bridge-local information, making it an ideal candidate for brownfield real-time network installations. A brief comparison with Asynchronous Traffic Shaping (ATS) shows that the achieved network utilization is comparable to that of ATS in some scenarios, while it only lags behind in scenarios with accumulating bursts where re-shaping could actually reduce the interference of the observed streams.
• Traffic Measurement Study on Video Streaming with the Amazon Echo Show. Loh, Frank; Vomhoff, Viktoria; Wamser, Florian; Metzger, Florian; Hoßfeld, Tobias. In 4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks. 2019.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
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  The Amazon Echo Show is one of the most widely used smart speakers with the ability to stream video. Due to its popularity, the traffc profiles of such devices are of interest to network operators and providers. This work presents a measurement study of the Amazon Echo Show in terms of network traffc and streaming behavior. More than 470 hours of streaming data are collected and analyzed at network layer. Based on this, streaming quality is derived at application layer. The study quantifies the traffc and shows that streaming with the Amazon Echo Show is comparable to streaming with a native web browser, but in a more conservative way.

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

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

  %0 Conference Paper %1 info3-inproceedings-2019-24 %A Hirth, Matthias %A Borchert, Kathrin %A Allendorf, Fabian %A Metzger, Florian %A Hoßfeld, Tobias %B 4th Internet-QoE Workshop: QoE-based Analysis and Management of Data Communication Networks (Internet-QoE'19) %C Los Cabos, Mexico %D 2019 %T Crowd-based Study of Gameplay Impairments and Player Performance in DOTA 2
• A Simulation of Asynchronous Traffic Shapers in Switched Ethernet Networks. Grigorjew, Alexej; Metzger, Florian; Hoßfeld, Tobias; Specht, Johannes. In Workshop for Advanced Communication Networks for Industrial Applications. 2019.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  As the requirements of real-time networking in- crease, the IEEE Time-Sensitive Networking (TSN) task group is working on new standards for high bandwidth and low latency Ethernet switching. In particular, the upcoming P802.1Qcr standard features Asynchronous Traffic Shaping (ATS), which is a promising approach for real-time networks with high dynamics and critical safety requirements. Additionally, parallel concepts such as frame preemption can be used to reduce delays even further. This work presents a discrete event simulation framework that can analyze the performance of these concepts. It implements frame preemption and multiple shaping algorithms, while recording latency and queue utilization statistics at the switches. In addition, an evaluation of a linear topology with four switches is performed under high link utilization, which demonstrates the benefit of the above mechanisms compared to regular Ethernet switching.

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

  %0 Conference Paper %1 info3-inproceedings-2019-16 %A Grigorjew, Alexej %A Metzger, Florian %A Hoßfeld, Tobias %A Specht, Johannes %B Workshop for Advanced Communication Networks for Industrial Applications %D 2019 %T A Simulation of Asynchronous Traffic Shapers in Switched Ethernet Networks %X As the requirements of real-time networking in- crease, the IEEE Time-Sensitive Networking (TSN) task group is working on new standards for high bandwidth and low latency Ethernet switching. In particular, the upcoming P802.1Qcr standard features Asynchronous Traffic Shaping (ATS), which is a promising approach for real-time networks with high dynamics and critical safety requirements. Additionally, parallel concepts such as frame preemption can be used to reduce delays even further. This work presents a discrete event simulation framework that can analyze the performance of these concepts. It implements frame preemption and multiple shaping algorithms, while recording latency and queue utilization statistics at the switches. In addition, an evaluation of a linear topology with four switches is performed under high link utilization, which demonstrates the benefit of the above mechanisms compared to regular Ethernet switching.
• Exploring the Transmission Behaviour of Overwatch: The Source of Lag. Metzger, Florian; Heger, Roman. In 30th International Teletraffic Congress (ITC 30). 2018.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  This paper explores the full chain of lag contribution factors in a specific online multiplayer game, namely Overwatch: From creating input events over the network and back to displaying the results on the local screen. Together result in the dreaded end-to-end lag. which has a direct impact on the subjective quality one experiences when playing video games. In its investigation, this paper reveals surprising effects in the game's networking behavior that are omitted when colloquially talking about, e.g. a 60 Hz update rate, but must be considered nonetheless. These insights, gained from examining network traces of Overwatch matches that were played on a realistic, resource constrained PC, can then be used to refine end-to-end lag simulation models and reach a better understanding of all responsible components.

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

  %0 Conference Paper %1 info3-inproceedings-2018-36 %A Metzger, Florian %A Heger, Roman %B 30th International Teletraffic Congress (ITC 30) %D 2018 %T Exploring the Transmission Behaviour of Overwatch: The Source of Lag %X This paper explores the full chain of lag contribution factors in a specific online multiplayer game, namely Overwatch: From creating input events over the network and back to displaying the results on the local screen. Together result in the dreaded end-to-end lag. which has a direct impact on the subjective quality one experiences when playing video games. In its investigation, this paper reveals surprising effects in the game's networking behavior that are omitted when colloquially talking about, e.g. a 60 Hz update rate, but must be considered nonetheless. These insights, gained from examining network traces of Overwatch matches that were played on a realistic, resource constrained PC, can then be used to refine end-to-end lag simulation models and reach a better understanding of all responsible components.
• Speed Index: Relating the Industrial Standard for User Perceived Web Performance to Web QoE. Hoßfeld, Tobias; Metzger, Florian; Rossi, Dario. In Proceedings of the 10th International Conference on Quality of Multimedia Experience (QoMEX 2018). Sardinia, Italy, 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2018-9, address = {Sardinia, Italy}, author = {Hoßfeld, Tobias and Metzger, Florian and Rossi, Dario}, booktitle = {Proceedings of the 10th International Conference on Quality of Multimedia Experience (QoMEX 2018)}, keywords = {fullstack}, month = {05}, title = {Speed Index: Relating the Industrial Standard for User Perceived Web Performance to Web QoE}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-9 %A Hoßfeld, Tobias %A Metzger, Florian %A Rossi, Dario %B Proceedings of the 10th International Conference on Quality of Multimedia Experience (QoMEX 2018) %C Sardinia, Italy %D 2018 %T Speed Index: Relating the Industrial Standard for User Perceived Web Performance to Web QoE
• Traffic Modeling for Aggregated Periodic IoT Data. Hoßfeld, Tobias; Metzger, Florian; Heegaard, Poul E. In Proceedings of the 21st Conference on Innovation in Clouds, Internet and Networks (ICIN). Paris, France, 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2018-6, address = {Paris, France}, author = {Hoßfeld, Tobias and Metzger, Florian and Heegaard, Poul E.}, booktitle = {Proceedings of the 21st Conference on Innovation in Clouds, Internet and Networks (ICIN)}, keywords = {fullstack}, month = {02}, title = {Traffic Modeling for Aggregated Periodic IoT Data}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-6 %A Hoßfeld, Tobias %A Metzger, Florian %A Heegaard, Poul E. %B Proceedings of the 21st Conference on Innovation in Clouds, Internet and Networks (ICIN) %C Paris, France %D 2018 %T Traffic Modeling for Aggregated Periodic IoT Data
• Viability of Wi-Fi Caches in an Era of HTTPS Prevalence. Moldovan, Christian; Burger, Valentin; Metzger, Florian; Surminski, Sebastian; Hoßfeld, Tobias. In 2017 IEEE International Conference on Communications Workshops (ICC Workshops). Paris, France, 2017.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Caches are often employed to better manage the ever-growing amount of global Internet traffic. Particularly, reverse proxies are often used to free up congested peering links and reduce inter-domain traffic. In addition, caches place content close to the edge, leading to lower latency which can be beneficial for many applications. In an effort to bring content even closer to end devices, home routers and public access points are now in the spotlight as a novel location for caches. Compared to CDNs, a Wi-Fi router only offers scarce storage and processing capabilities, putting an increased emphasis on resource management. In addition, a large share of traffic is transmitted through secured connections preventing the use of forward caches and other middle boxes. This paper strives to analyze how effective caching can be in public Wi-Fi routers. For this purpose, we conducted a field study with caches at public Wi-Fi hotspots in a field study. In addition, we present a queueing model for caches that we use to perform a mean-value analysis. We compare results from both methods in a performance analysis. Our results provide insights into difficulties of caching systems that are caused by an increase in the ratio of secured connections in the Internet.

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

  %0 Conference Paper %1 info3-inproceedings-2017-8 %A Moldovan, Christian %A Burger, Valentin %A Metzger, Florian %A Surminski, Sebastian %A Hoßfeld, Tobias %B 2017 IEEE International Conference on Communications Workshops (ICC Workshops) %C Paris, France %D 2017 %T Viability of Wi-Fi Caches in an Era of HTTPS Prevalence %X Caches are often employed to better manage the ever-growing amount of global Internet traffic. Particularly, reverse proxies are often used to free up congested peering links and reduce inter-domain traffic. In addition, caches place content close to the edge, leading to lower latency which can be beneficial for many applications. In an effort to bring content even closer to end devices, home routers and public access points are now in the spotlight as a novel location for caches. Compared to CDNs, a Wi-Fi router only offers scarce storage and processing capabilities, putting an increased emphasis on resource management. In addition, a large share of traffic is transmitted through secured connections preventing the use of forward caches and other middle boxes. This paper strives to analyze how effective caching can be in public Wi-Fi routers. For this purpose, we conducted a field study with caches at public Wi-Fi hotspots in a field study. In addition, we present a queueing model for caches that we use to perform a mean-value analysis. We compare results from both methods in a performance analysis. Our results provide insights into difficulties of caching systems that are caused by an increase in the ratio of secured connections in the Internet.
• Bridging the Gap between QoE and User Engagement in HTTP Video Streaming. Moldovan, Christian; Metzger, Florian. In 28th International Teletraffic Congress (ITC 28). 2016.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  On video streaming platforms, users expect a high Quality of Experience (QoE). In contrast, service and content providers aim at high User Engagement, most notably because their revenue is usually dependent on it. In order to satisfy users, it is critical to know how QoE is related to the User Engagement. However, no model for this relation exists yet. Current approaches to managing QoE are usually based on traffic analysis. However, this will become more difficult in the future since the encryption of Internet traffic progresses. In this paper, we present an approach to bringing QoE and User Engagement together with video streaming as the use case. We do this by fitting existing measurement data of User Engagement to obtain a model. Furthermore, we extend the existing queuing model for QoE and investigate the correlation between QoE and User Engagement in a simulation. Hereby, we model different scenarios where we quantify network bandwidth and video requirements. Our results show that there is a strong correlation between QoE and User Engagement. Additionally, we observe that simple buffer policies, which do not rely on buffer information, can still perform well. These revelations open the way for new approaches to QoE Management in the future Internet.

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

  %0 Conference Paper %1 info3-inproceedings-2016-30 %A Moldovan, Christian %A Metzger, Florian %B 28th International Teletraffic Congress (ITC 28) %D 2016 %T Bridging the Gap between QoE and User Engagement in HTTP Video Streaming %X On video streaming platforms, users expect a high Quality of Experience (QoE). In contrast, service and content providers aim at high User Engagement, most notably because their revenue is usually dependent on it. In order to satisfy users, it is critical to know how QoE is related to the User Engagement. However, no model for this relation exists yet. Current approaches to managing QoE are usually based on traffic analysis. However, this will become more difficult in the future since the encryption of Internet traffic progresses. In this paper, we present an approach to bringing QoE and User Engagement together with video streaming as the use case. We do this by fitting existing measurement data of User Engagement to obtain a model. Furthermore, we extend the existing queuing model for QoE and investigate the correlation between QoE and User Engagement in a simulation. Hereby, we model different scenarios where we quantify network bandwidth and video requirements. Our results show that there is a strong correlation between QoE and User Engagement. Additionally, we observe that simple buffer policies, which do not rely on buffer information, can still perform well. These revelations open the way for new approaches to QoE Management in the future Internet.
• Assessing the Accuracy of Network Estimations in the DOTA 2 Game Client. Hirth, Matthias; Allendorf, Fabian; Metzger, Florian; Schwartz, Christian. In Workshop on Perceptual Quality of Systems (PQS). Berlin, Germany, 2016.
  • [ Abstract ]
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  Online video games and the subjective quality of player inter- actions with them rely on good network conditions. Almost equally important is a good and timely knowledge of such conditions in order to take proper countermeasures to worsening conditions. To this end, many online video games include components for estimating the current network status. In this paper, we examine the accuracy of those estimations for the popular competitive multiplayer game DOTA 2. Our results show that the game client is capable of performing a good estimation of the delay and packet loss, but only after a rather large initial delay.

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

  %0 Conference Paper %1 info3-inproceedings-2016-13 %A Hirth, Matthias %A Allendorf, Fabian %A Metzger, Florian %A Schwartz, Christian %B Workshop on Perceptual Quality of Systems (PQS) %C Berlin, Germany %D 2016 %T Assessing the Accuracy of Network Estimations in the DOTA 2 Game Client %X Online video games and the subjective quality of player inter- actions with them rely on good network conditions. Almost equally important is a good and timely knowledge of such conditions in order to take proper countermeasures to worsening conditions. To this end, many online video games include components for estimating the current network status. In this paper, we examine the accuracy of those estimations for the popular competitive multiplayer game DOTA 2. Our results show that the game client is capable of performing a good estimation of the delay and packet loss, but only after a rather large initial delay.
• A Comprehensive End-to-End Lag Model for Online and Cloud Video Gaming. Metzger, Florian; Rafetseder, Albert; Schwartz, Christian. In Proc. 5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS 2016). 2016.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  To further the knowledge of basic game mechanics and improve future video game Quality of Experience (QoE) studies we present a model and simulation for End-to-End (E2E) lag in networked and cloud computer games. E2E lag describes the latency between a user's action and the display of the action's results on the screen, thus providing both a basic measure for interactivity and a fundamental parameter to derived QoE metrics. In contrast to E2E lag models that focus on the network Round-Trip Time (RTT), the presented work also factors in the game's tickrate and framerate (and codec latencies in the case of cloud games). This reveals side effects that can entirely mask the network delay's contribution to the total lag, an important notion to consider for future game studies.

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

  %0 Conference Paper %1 info3-inproceedings-2016-31 %A Metzger, Florian %A Rafetseder, Albert %A Schwartz, Christian %B Proc. 5th ISCA/DEGA Workshop on Perceptual Quality of Systems (PQS 2016) %D 2016 %T A Comprehensive End-to-End Lag Model for Online and Cloud Video Gaming %X To further the knowledge of basic game mechanics and improve future video game Quality of Experience (QoE) studies we present a model and simulation for End-to-End (E2E) lag in networked and cloud computer games. E2E lag describes the latency between a user's action and the display of the action's results on the screen, thus providing both a basic measure for interactivity and a fundamental parameter to derived QoE metrics. In contrast to E2E lag models that focus on the network Round-Trip Time (RTT), the presented work also factors in the game's tickrate and framerate (and codec latencies in the case of cloud games). This reveals side effects that can entirely mask the network delay's contribution to the total lag, an important notion to consider for future game studies.
• QoE Management made uneasy: The case of Cloud Gaming. Sackl, Andreas; Schatz, Raimund; Hoßfeld, Tobias; Metzger, Florian; Lister, David; Irmer, Ralf. In IEEE Workshop on Quality of Experience-based Management for Future Internet Applications and Services (QoE-FI). 2016.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2016-26, author = {Sackl, Andreas and Schatz, Raimund and Hoßfeld, Tobias and Metzger, Florian and Lister, David and Irmer, Ralf}, booktitle = {IEEE Workshop on Quality of Experience-based Management for Future Internet Applications and Services (QoE-FI)}, keywords = {sys:hidden:inproceedings}, title = {QoE Management made uneasy: The case of Cloud Gaming}, year = 2016 }

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

  %0 Conference Paper %1 info3-inproceedings-2016-25 %A Liotou, Eirini %A Hoßfeld, Tobias %A Moldovan, Christian %A Metzger, Florian %A Tsolkas, Dimitris %A Passas, Nikos %B IEEE International Conference on Communications Workshops (ICC) %D 2016 %T Enriching HTTP adaptive streaming with context awareness: A tunnel case study
• Games and frames: A strange tale of QoE studies. Metzger, Florian; Rafetseder, Albert; Schwartz, Christian; Hoßfeld, Tobias. In Eighth International Conference on Quality of Multimedia Experience (QoMEX). 2016.
  • [ BibTeX ]
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  @inproceedings{info3-inproceedings-2016-27, author = {Metzger, Florian and Rafetseder, Albert and Schwartz, Christian and Hoßfeld, Tobias}, booktitle = {Eighth International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:inproceedings}, title = {Games and frames: A strange tale of QoE studies}, year = 2016 }

  %0 Conference Paper %1 info3-inproceedings-2016-27 %A Metzger, Florian %A Rafetseder, Albert %A Schwartz, Christian %A Hoßfeld, Tobias %B Eighth International Conference on Quality of Multimedia Experience (QoMEX) %D 2016 %T Games and frames: A strange tale of QoE studies
• A Simulation Framework for Evaluating the QoS and QoE of TCP-based Streaming in an LTE Network. Metzger, Florian; Steindl, Christoph; Hoßfeld, Tobias. In 27th International Teletraffic Congress (ITC). Ghent, Belgium, 2015.
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  @inproceedings{info3-inproceedings-2015-29, address = {Ghent, Belgium}, author = {Metzger, Florian and Steindl, Christoph and Hoßfeld, Tobias}, booktitle = {27th International Teletraffic Congress (ITC)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {A Simulation Framework for Evaluating the QoS and QoE of TCP-based Streaming in an LTE Network}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-29 %A Metzger, Florian %A Steindl, Christoph %A Hoßfeld, Tobias %B 27th International Teletraffic Congress (ITC) %C Ghent, Belgium %D 2015 %T A Simulation Framework for Evaluating the QoS and QoE of TCP-based Streaming in an LTE Network
• GTP-based Load Model and Virtualization Gain for a Mobile Network’s GGSN. Metzger, Florian; Schwartz, Christian; Hoßfeld, Tobias. In 5th International Conference on Communications and Electronics. Da Nang, Vietnam, 2014.
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  Multiple outages in major mobile networks have been reported in the recent past. In fixed and datacenter networks, such capacity problems are solved by scaling out, i.e. purchasing additional hardware. In mobile networks this is not easily possible as network components are usually sold as sealed middleboxes. With the advances in server performance and SDN it has been suggested to virtualize these boxes. This also opens up opportunities to dimension according to current load and save energy by switching off parts of the infrastructure. Such suggestions immediately raise the question on the cost of virtualization. To answer this question, we introduce models for both a traditional as well as a virtualized GGSN. In addition, we provide distributions for the load experienced at the GGSN based on network measurements. With this at hand, we study the influence of different dimensioning parameters on important performance metrics, with special consideration for the impact of provisioning new instances for the virtual GGSN.

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

  %0 Conference Paper %1 info3-inproceedings-2014-497 %A Metzger, Florian %A Schwartz, Christian %A Hoßfeld, Tobias %B 5th International Conference on Communications and Electronics %C Da Nang, Vietnam %D 2014 %T GTP-based Load Model and Virtualization Gain for a Mobile Network's GGSN %X Multiple outages in major mobile networks have been reported in the recent past. In fixed and datacenter networks, such capacity problems are solved by scaling out, i.e. purchasing additional hardware. In mobile networks this is not easily possible as network components are usually sold as sealed middleboxes. With the advances in server performance and SDN it has been suggested to virtualize these boxes. This also opens up opportunities to dimension according to current load and save energy by switching off parts of the infrastructure. Such suggestions immediately raise the question on the cost of virtualization. To answer this question, we introduce models for both a traditional as well as a virtualized GGSN. In addition, we provide distributions for the load experienced at the GGSN based on network measurements. With this at hand, we study the influence of different dimensioning parameters on important performance metrics, with special consideration for the impact of provisioning new instances for the virtual GGSN.
• A performance evaluation framework for video streaming. Metzger, Florian; Rafetseder, Albert; Tutschku, Kurt. In 19th International Packet Video Workshop (PV). 2012.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  In this paper, we present a generic framework for performance evaluation of video streams. We embrace the perspective of a streaming application, and model the playback buffer level at given network and playback conditions. That way, our model enables flexible, adaptable evaluation of a wide variety of streaming methods and protocols. We test our model on HTML5 and Flash video as served by the YouTube web site. We find universal achievable limits in any streaming process, and explore quality trade-offs every application has to decide on.

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

  %0 Conference Paper %1 info3-inproceedings-2012-27 %A Metzger, Florian %A Rafetseder, Albert %A Tutschku, Kurt %B 19th International Packet Video Workshop (PV) %D 2012 %T A performance evaluation framework for video streaming %X In this paper, we present a generic framework for performance evaluation of video streams. We embrace the perspective of a streaming application, and model the playback buffer level at given network and playback conditions. That way, our model enables flexible, adaptable evaluation of a wide variety of streaming methods and protocols. We test our model on HTML5 and Flash video as served by the YouTube web site. We find universal achievable limits in any streaming process, and explore quality trade-offs every application has to decide on.
• Exploring YouTube’s content distribution network through distributed application-layer measurements: a first view. Rafetseder, Albert; Metzger, Florian; Stezenbach, David; Tutschku, Kurt. In Proceedings of the 2011 International Workshop on Modeling, Analysis, and Control of Complex Networks (Cnet ’11). 2011.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2011-27, author = {Rafetseder, Albert and Metzger, Florian and Stezenbach, David and Tutschku, Kurt}, booktitle = {Proceedings of the 2011 International Workshop on Modeling, Analysis, and Control of Complex Networks (Cnet '11)}, keywords = {sys:hidden:inproceedings}, month = {09}, title = {Exploring YouTube's content distribution network through distributed application-layer measurements: a first view}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-27 %A Rafetseder, Albert %A Metzger, Florian %A Stezenbach, David %A Tutschku, Kurt %B Proceedings of the 2011 International Workshop on Modeling, Analysis, and Control of Complex Networks (Cnet '11) %D 2011 %T Exploring YouTube's content distribution network through distributed application-layer measurements: a first view
• Analysis of web-based video delivery. Metzger, Florian; Rafetseder, Albert; Stezenbach, David; Tutschku, Kurt. In 50th FITCE Congress - "ICT: Bridging an Ever Shifting Digital Divide". 2011.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2011-28, author = {Metzger, Florian and Rafetseder, Albert and Stezenbach, David and Tutschku, Kurt}, booktitle = {50th FITCE Congress - "ICT: Bridging an Ever Shifting Digital Divide"}, keywords = {sys:hidden:inproceedings}, month = {08}, title = {Analysis of web-based video delivery}, year = 2011 }

  %0 Conference Paper %1 info3-inproceedings-2011-28 %A Metzger, Florian %A Rafetseder, Albert %A Stezenbach, David %A Tutschku, Kurt %B 50th FITCE Congress - "ICT: Bridging an Ever Shifting Digital Divide" %D 2011 %T Analysis of web-based video delivery
• Pushing the Performance of Biased Neighbor Selection through Biased Unchoking. Oechsner, Simon; Lehrieder, Frank; Hoßfeld, Tobias; Metzger, Florian; Pussep, Konstantin; Staehle, Dirk. In 9th International Conference on Peer-to-Peer Computing. Seattle, USA, 2009.
  • [ Abstract ]
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  Locality promotion in P2P content distribution networks is currently a major research topic. One of the goals of all discussed approaches is to reduce the interdomain traffic that causes high costs for ISPs. However, the focus of the work in this field is generally on the type of locality information that is provided to the overlay and on the entities that exchange this information. An aspect that is generally neglected is how this information is used by the peers. In this paper, we consider the predominant approach of Biased Neighbor Selection and compare it with Biased Unchoking, an alternative locality aware peer selection strategy we propose in this paper. We show that both mechanisms complement each other for the BitTorrent file sharing application and achieve the best performance when combined.

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

  %0 Conference Paper %1 info3-inproceedings-2009-355 %A Oechsner, Simon %A Lehrieder, Frank %A Hoßfeld, Tobias %A Metzger, Florian %A Pussep, Konstantin %A Staehle, Dirk %B 9th International Conference on Peer-to-Peer Computing %C Seattle, USA %D 2009 %T Pushing the Performance of Biased Neighbor Selection through Biased Unchoking %X Locality promotion in P2P content distribution networks is currently a major research topic. One of the goals of all discussed approaches is to reduce the interdomain traffic that causes high costs for ISPs. However, the focus of the work in this field is generally on the type of locality information that is provided to the overlay and on the entities that exchange this information. An aspect that is generally neglected is how this information is used by the peers. In this paper, we consider the predominant approach of Biased Neighbor Selection and compare it with Biased Unchoking, an alternative locality aware peer selection strategy we propose in this paper. We show that both mechanisms complement each other for the BitTorrent file sharing application and achieve the best performance when combined.

• Subjective And Objective Assessment Of Video Game Context Factors. Metzger, Florian; Schröder, Svenja; Ratetseder, Albert. 2021, August.
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  @misc{info3-misc-2021-1, author = {Metzger, Florian and Schröder, Svenja and Ratetseder, Albert}, howpublished = {https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-242471}, keywords = {sys:hidden:misc}, month = {08}, title = {Subjective And Objective Assessment Of Video Game Context Factors}, year = 2021 }

  %0 Generic %1 info3-misc-2021-1 %A Metzger, Florian %A Schröder, Svenja %A Ratetseder, Albert %D 2021 %T Subjective And Objective Assessment Of Video Game Context Factors
• The Prospects of Cloud Gaming: Do the Benefits Outweigh the Costs?. Metzger, Florian; Rafetseder, Albert; Schröder, Svenja; Zwickl, Patrick. 2021, August.
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  @misc{info3-misc-2021-2, author = {Metzger, Florian and Rafetseder, Albert and Schröder, Svenja and Zwickl, Patrick}, howpublished = {https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-242452}, keywords = {sys:hidden:misc}, month = {08}, title = {The Prospects of Cloud Gaming: Do the Benefits Outweigh the Costs?}, year = 2021 }

  %0 Generic %1 info3-misc-2021-2 %A Metzger, Florian %A Rafetseder, Albert %A Schröder, Svenja %A Zwickl, Patrick %D 2021 %T The Prospects of Cloud Gaming: Do the Benefits Outweigh the Costs?
• Crowdsensed QoE for the community - a concept to make QoE assessment accessible. Metzger, Florian. 2020, May.
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  @misc{info3-misc-2020-2, author = {Metzger, Florian}, howpublished = {https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-203748}, keywords = {sys:hidden:misc}, month = {05}, title = {Crowdsensed QoE for the community - a concept to make QoE assessment accessible}, year = 2020 }

  %0 Generic %1 info3-misc-2020-2 %A Metzger, Florian %D 2020 %T Crowdsensed QoE for the community - a concept to make QoE assessment accessible

• Evaluating reliable streaming in mobile networks. Technical Report (PhD dissertation), . Metzger, Florian. PhD dissertation. University of Vienna, 2014, December.
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  @phdthesis{info3-dissertation-2014-4, author = {Metzger, Florian}, keywords = {sys:hidden:supervisor:peter.reichel}, month = 12, school = {University of Vienna}, title = {Evaluating reliable streaming in mobile networks}, year = 2014 }

  %0 Thesis %1 info3-dissertation-2014-4 %A Metzger, Florian %D 2014 %T Evaluating reliable streaming in mobile networks

• Signaling Load and Tunnel Management in a 3G Core Network. Technical Report (484), . Metzger, Florian; Gebert, Steffen; Salzlechner, Katharina; Rafetseder, Albert; Romirer, Peter; Tutschku, Kurt. University of Wuerzburg, 2012.
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  @techreport{info3-techreport-2012-259, author = {Metzger, Florian and Gebert, Steffen and Salzlechner, Katharina and Rafetseder, Albert and Romirer, Peter and Tutschku, Kurt}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = {09}, number = 484, title = {Signaling Load and Tunnel Management in a 3G Core Network}, year = 2012 }

  %0 Report %1 info3-techreport-2012-259 %A Metzger, Florian %A Gebert, Steffen %A Salzlechner, Katharina %A Rafetseder, Albert %A Romirer, Peter %A Tutschku, Kurt %D 2012 %N 484 %T Signaling Load and Tunnel Management in a 3G Core Network
• Pushing the Performance of Biased Neighbor Selection through Biased Unchoking. Technical Report (459), . Oechsner, Simon; Lehrieder, Frank; Hoßfeld, Tobias; Metzger, Florian; Pussep, Konstantin; Staehle, Dirk. University of Wuerzburg, 2009.
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  @techreport{info3-techreport-2009-245, author = {Oechsner, Simon and Lehrieder, Frank and Hoßfeld, Tobias and Metzger, Florian and Pussep, Konstantin and Staehle, Dirk}, institution = {University of Wuerzburg}, keywords = {sys:hidden:techreport}, month = {08}, number = 459, title = {Pushing the Performance of Biased Neighbor Selection through Biased Unchoking}, year = 2009 }

  %0 Report %1 info3-techreport-2009-245 %A Oechsner, Simon %A Lehrieder, Frank %A Hoßfeld, Tobias %A Metzger, Florian %A Pussep, Konstantin %A Staehle, Dirk %D 2009 %N 459 %T Pushing the Performance of Biased Neighbor Selection through Biased Unchoking