Dr. rer. nat. Christian Moldovan

• 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.

• Optimizing HAS for 360-Degree Videos. Moldovan, Christian; Loh, Frank; Seufert, Michael; Hoßfeld, Tobias. In 5th IEEE/IFIP International Workshop on Analytics for Network and Service Management (AnNet). Budapest, Hungary, 2020.
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  @inproceedings{info3-inproceedings-2020-1, address = {Budapest, Hungary}, author = {Moldovan, Christian and Loh, Frank and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {5th IEEE/IFIP International Workshop on Analytics for Network and Service Management (AnNet)}, keywords = {net-man}, month = {04}, title = {Optimizing HAS for 360-Degree Videos}, year = 2020 }

  %0 Conference Paper %1 info3-inproceedings-2020-1 %A Moldovan, Christian %A Loh, Frank %A Seufert, Michael %A Hoßfeld, Tobias %B 5th IEEE/IFIP International Workshop on Analytics for Network and Service Management (AnNet) %C Budapest, Hungary %D 2020 %T Optimizing HAS for 360-Degree Videos
• Don’t Stop the Music: Crowdsourced QoE Assessment of Music Streaming with Stalling. Schwind, Anika; Moldovan, Christian; Janiak, Tim; Dworschak, Nemo-Dario; Hoßfeld, Tobias. In 12th International Conference on Quality of Multimedia Experience (QoMEX). Athlone, Ireland, 2020.
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  Streaming made a lasting effect on the way our society consumes media in the last decade. While due to streaming the way we listen to music and podcasts has changed drastically, there are very few studies about its Quality of Experience (QoE) and possible influence factors. From video QoE studies, we know that, for example, undesirable stops of the stream (stalling events) have a significant impact on QoE. However, the way in which music and video streaming is consumed differs significantly, as music is often played in the background, and thus, the influence of stalling could be significantly different. Thus, this work evaluates the impact of stalling on music streaming QoE. Therefore, we conduct two crowdsourced user studies: In the first study, users have to rate four songs with different stalling patterns and evaluate the degree of impairments. Afterwards, we compare the ratings to the results of a lab study and show that they are highly correlated, and that crowdsourcing is a suitable way of measuring music streaming QoE. In addition, we conduct a second crowdsourcing study to investigate the influence of the user's attentiveness on QoE. Here, participants have to listen to one song with two stalling events, while one half of them had to transcribe a handwritten text with music playing in the background. The attentiveness shows no influence on the perceived streaming quality, but it shows a significant influence on the perceived quality degradation due to stalling events. Furthermore, considerably more stalling events were missed for workers who focused on the transcription. These results are an important step towards establishing new methods for investigating QoE in multimedia.

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

  %0 Conference Paper %1 info3-inproceedings-2020-7 %A Schwind, Anika %A Moldovan, Christian %A Janiak, Tim %A Dworschak, Nemo-Dario %A Hoßfeld, Tobias %B 12th International Conference on Quality of Multimedia Experience (QoMEX) %C Athlone, Ireland %D 2020 %T Don’t Stop the Music: Crowdsourced QoE Assessment of Music Streaming with Stalling %X Streaming made a lasting effect on the way our society consumes media in the last decade. While due to streaming the way we listen to music and podcasts has changed drastically, there are very few studies about its Quality of Experience (QoE) and possible influence factors. From video QoE studies, we know that, for example, undesirable stops of the stream (stalling events) have a significant impact on QoE. However, the way in which music and video streaming is consumed differs significantly, as music is often played in the background, and thus, the influence of stalling could be significantly different. Thus, this work evaluates the impact of stalling on music streaming QoE. Therefore, we conduct two crowdsourced user studies: In the first study, users have to rate four songs with different stalling patterns and evaluate the degree of impairments. Afterwards, we compare the ratings to the results of a lab study and show that they are highly correlated, and that crowdsourcing is a suitable way of measuring music streaming QoE. In addition, we conduct a second crowdsourcing study to investigate the influence of the user's attentiveness on QoE. Here, participants have to listen to one song with two stalling events, while one half of them had to transcribe a handwritten text with music playing in the background. The attentiveness shows no influence on the perceived streaming quality, but it shows a significant influence on the perceived quality degradation due to stalling events. Furthermore, considerably more stalling events were missed for workers who focused on the transcription. These results are an important step towards establishing new methods for investigating QoE in multimedia.
• Is the Uplink Enough? Estimating Video Stalls from Encrypted Network Traffic. Loh, Frank; Wamser, Florian; Moldovan, Christian; Zeidler, Bernd; Tsilimantos, Dimitrios; Valentin, Stefan; Hoßfeld, Tobias. In 32th IEEE/IFIP Network Operations and Management Symposium. Budapest, Hungary, 2020.
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  Today’s traffic projections speak of almost 58 % video traffic across the Internet. Nearly all video traffic is encrypted, accounting for more than 50 % encrypted traffic worldwide. To analyze video traffic today, or even estimate its quality in the network, a deep look into the traffic characteristics has to be done. But then, important quality metrics from the traffic behavior can be derived. Based on extensive measurements we show in this work how to measure and estimate video stalls for mobile adaptive streaming. The underlying dataset includes more than 900 hours of video footage from the native YouTube app, measured over 18 different videos in 56 network scenarios in two cities in Europe. We outline a possible approach to estimate the video playback buffer size based on uplink video chunk requests in real-time to break down the video stalls. This work is intended as a tool for network operators to receive further knowledge of the characteristics of video streaming traffic to quantify the most important QoE degradation factors of one of the most important applications today.

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

  %0 Conference Paper %1 info3-inproceedings-2020-2 %A Loh, Frank %A Wamser, Florian %A Moldovan, Christian %A Zeidler, Bernd %A Tsilimantos, Dimitrios %A Valentin, Stefan %A Hoßfeld, Tobias %B 32th IEEE/IFIP Network Operations and Management Symposium %C Budapest, Hungary %D 2020 %T Is the Uplink Enough? Estimating Video Stalls from Encrypted Network Traffic %X Today’s traffic projections speak of almost 58 % video traffic across the Internet. Nearly all video traffic is encrypted, accounting for more than 50 % encrypted traffic worldwide. To analyze video traffic today, or even estimate its quality in the network, a deep look into the traffic characteristics has to be done. But then, important quality metrics from the traffic behavior can be derived. Based on extensive measurements we show in this work how to measure and estimate video stalls for mobile adaptive streaming. The underlying dataset includes more than 900 hours of video footage from the native YouTube app, measured over 18 different videos in 56 network scenarios in two cities in Europe. We outline a possible approach to estimate the video playback buffer size based on uplink video chunk requests in real-time to break down the video stalls. This work is intended as a tool for network operators to receive further knowledge of the characteristics of video streaming traffic to quantify the most important QoE degradation factors of one of the most important applications today.

• Contributions to TF "Managing Web & Cloud QoE". Moldovan, Christian. 13th Qualinet General Meeting, Berlin, Germany, 2019, June 4.
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  @presentation{info3-presentation-2019-6, address = {13th Qualinet General Meeting, Berlin, Germany}, author = {Moldovan, Christian}, keywords = {sys:hidden:presentation}, month = {06}, title = {Contributions to TF "Managing Web & Cloud QoE"}, year = 2019 }

  %0 Generic %1 info3-presentation-2019-6 %A Moldovan, Christian %C 13th Qualinet General Meeting, Berlin, Germany %D 2019 %T Contributions to TF "Managing Web & Cloud QoE"
• User Behavior and Engagement of a Mobile Video Streaming User from Crowdsourced Measurements. Moldovan, Christian. Berlin, Germany, 2019, June.
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  @misc{info3-poster-2019-1, address = {Berlin, Germany}, author = {Moldovan, Christian}, booktitle = {2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {sys:hidden:poster}, month = {06}, title = {User Behavior and Engagement of a Mobile Video Streaming User from Crowdsourced Measurements}, year = 2019 }

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

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

  %0 Conference Paper %1 info3-inproceedings-2019-25 %A Loh, Frank %A Wamser, Florian %A Moldovan, Christian %A Zeidler, Bernd %A Hoßfeld, Tobias %A Tsilimantos, Dimitrios %A Valentin, Stefan %B Proceedings of the 10th ACM Multimedia Systems Conference %D 2019 %P 267-272 %T From click to playback: a dataset to study the response time of mobile YouTube %X Responding fluently to user requests is important to keep them immersed. In this paper, we are presenting an extensive dataset to study the response time of YouTube's mobile video streaming service on Android. We illustrate the application of our dataset by studying YouTube's initial delay for a subset of 9 videos in 75 network scenarios. We find that in 41% of the cases, YouTube exceeds the attention span of a typical user, while deep immersion is only reached in 15% of the cases. Our factor analysis implies that the allocation of the initial CDN node is the critical link in this delay chain. Since our dataset includes a large variety of factors, we are describing setup, methodology, and data structure in detail. Our dataset and measurement tools are publicly available.
• User Behavior and Engagement of a Mobile Video Streaming User from Crowdsourced Measurements. Moldovan, Christian; Wamser, Florian; Hoßfeld, Tobias. In 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX). 2019.
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  Mobile video streaming has gained a lot of popularity in recent year with the introduction of large data plans for mobile phones. While users in non-mobile scenarios have become accustomed to high quality and few stalling events, this is not the case in mobile environments. People are more likely to tolerate stalling since they know high throughput coverage cannot always be guaranteed. Their behavior and their engagement are drastically different when watching videos on mobile devices. In this paper, we characterize mobile phone users who use a video streaming application. We present a data set of over 6,000 video views from a crowdsourced video measurement study. We investigate user activity and engagement during video streaming and how such metrics are correlated with each other. This is the first study that goes beyond user engagement and investigates the direct behavior of mobile video users outside the lab which is an important step towards mobile QoE management.

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

  %0 Conference Paper %1 info3-inproceedings-2019-21 %A Moldovan, Christian %A Wamser, Florian %A Hoßfeld, Tobias %B 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX) %D 2019 %T User Behavior and Engagement of a Mobile Video Streaming User from Crowdsourced Measurements %X Mobile video streaming has gained a lot of popularity in recent year with the introduction of large data plans for mobile phones. While users in non-mobile scenarios have become accustomed to high quality and few stalling events, this is not the case in mobile environments. People are more likely to tolerate stalling since they know high throughput coverage cannot always be guaranteed. Their behavior and their engagement are drastically different when watching videos on mobile devices. In this paper, we characterize mobile phone users who use a video streaming application. We present a data set of over 6,000 video views from a crowdsourced video measurement study. We investigate user activity and engagement during video streaming and how such metrics are correlated with each other. This is the first study that goes beyond user engagement and investigates the direct behavior of mobile video users outside the lab which is an important step towards mobile QoE management.
• Energy-Efficient Adaptation Logic for HTTP Streaming in Mobile Networks. Moldovan, Christian. 2019 International Conference on Networked Systems (NetSys), Garching, Germany, 2019, March 20.
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  @presentation{info3-presentation-2019-7, address = {2019 International Conference on Networked Systems (NetSys), Garching, Germany}, author = {Moldovan, Christian}, keywords = {sys:hidden:presentation}, month = {03}, title = {Energy-Efficient Adaptation Logic for HTTP Streaming in Mobile Networks}, year = 2019 }

  %0 Generic %1 info3-presentation-2019-7 %A Moldovan, Christian %C 2019 International Conference on Networked Systems (NetSys), Garching, Germany %D 2019 %T Energy-Efficient Adaptation Logic for HTTP Streaming in Mobile Networks
• Peeking under the Hood – How the Measurement Setup Influences the Video Streaming Behavior. Schwind, Anika; Janiak, Lea; Moldovan, Christian; Wamser, Florian; Hoßfeld, Tobias. In The 3rd International Workshop on Quality of Experience Management (QoE-Management 2019). Paris, France, 2019.
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  Global Internet video traffic will dramatically increase in the next years. With this rapid growth, interest in the application behavior of video streaming services and the resulting user experience rises. In particular, there is a need to understand the influence of system parameters on the streaming performance. Thus, several monitoring approaches have been developed which allow conducting automated measurements on a large-scale, for example, lightweight approaches for measurements running in the mobile networks or setups using a virtual frame buffer for servers without a display running in virtualized cloud environments. In some cases, the measurement hardware can totally be controlled, in other cases, there is no knowledge about parallel running services. In this paper, we answer the question whether and how much the measurement setup (e.g., virtualization, headless browsers, load on machines) influences the video streaming behavior. Therefore, we compare eight management setups with the ground truth (an end user watching a video on the own device) by evaluating the key performance indicators on application layer during video streaming, i.e. initial video playout delays and stalling. Our results reveal important insights: some of the common measurement setups heavily influence the measurements and must be avoided to collect reliable results.

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

  %0 Conference Paper %1 info3-inproceedings-2019-6 %A Schwind, Anika %A Janiak, Lea %A Moldovan, Christian %A Wamser, Florian %A Hoßfeld, Tobias %B The 3rd International Workshop on Quality of Experience Management (QoE-Management 2019) %C Paris, France %D 2019 %T Peeking under the Hood – How the Measurement Setup Influences the Video Streaming Behavior %X Global Internet video traffic will dramatically increase in the next years. With this rapid growth, interest in the application behavior of video streaming services and the resulting user experience rises. In particular, there is a need to understand the influence of system parameters on the streaming performance. Thus, several monitoring approaches have been developed which allow conducting automated measurements on a large-scale, for example, lightweight approaches for measurements running in the mobile networks or setups using a virtual frame buffer for servers without a display running in virtualized cloud environments. In some cases, the measurement hardware can totally be controlled, in other cases, there is no knowledge about parallel running services. In this paper, we answer the question whether and how much the measurement setup (e.g., virtualization, headless browsers, load on machines) influences the video streaming behavior. Therefore, we compare eight management setups with the ground truth (an end user watching a video on the own device) by evaluating the key performance indicators on application layer during video streaming, i.e. initial video playout delays and stalling. Our results reveal important insights: some of the common measurement setups heavily influence the measurements and must be avoided to collect reliable results.
• Energy-Efficient Adaptation Logic for HTTP Streaming in Mobile Networks. Moldovan, Christian; Wamser, Florian; Hoßfeld, Tobias. In 2019 International Conference on Networked Systems (NetSys). 2019.
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  The requirements for video streaming have changed drastically during the past years. In today's Internet, high definition resolutions are considered default for videos, even in mobile settings, and with 4G penetration reaching 90 percent in the US, this no longer poses a big problem. However, while mobile bandwidth has increased, the battery life time of mobile devices has not increased significantly. Furthermore, current data plans are still not large enough to regularly stream movies during the commute. Users still resort to downloading media before travel. In this paper we propose a new HTTP adaptive streaming algorithm that delivers videos in high quality while avoiding stalling events, schedules the download of video segments so that a energy conserving idle state is often reached and keeps the buffer low at points in the video where many viewers abandon the video to save data. While most adaptive streaming algorithms optimize quality and stalling, this is the first attempt to use an adaptive streaming algorithm to reduce energy consumption. Since video streaming providers mostly care about the Quality of Experience when watching videos, energy efficiency is left to the device manufacturers. Therefore, both parties have little incentive to cooperate in this regard. But on the Internet of tomorrow, where most videos are watched on mobile devices, energy efficiency and the Quality of Experience must go hand in hand.

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

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

• Optimal Fairness and Quality in Video Streaming With Multiple Users. Moldovan, Christian. 30th International Teletraffic Congress (ITC 30), Vienna, Austria, 2018, September 4.
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  @presentation{info3-presentation-2018-6, address = {30th International Teletraffic Congress (ITC 30), Vienna, Austria}, author = {Moldovan, Christian}, keywords = {sys:hidden:presentation}, month = {09}, title = {Optimal Fairness and Quality in Video Streaming With Multiple Users}, year = 2018 }

  %0 Generic %1 info3-presentation-2018-6 %A Moldovan, Christian %C 30th International Teletraffic Congress (ITC 30), Vienna, Austria %D 2018 %T Optimal Fairness and Quality in Video Streaming With Multiple Users
• Optimal Fairness and Quality in Video Streaming With Multiple Users. Moldovan, Christian; Skorin-Kapov, Lea; Heegaard, Poul E.; Hoßfeld, Tobias. In 30th International Teletraffic Congress (ITC 30), p. 6. Vienna, Austria, 2018.
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  • [ BibTeX ]
  • [ EndNote ]
  With the majority of video distribution services relying on the HTTP adaptive streaming paradigm, a great deal of research is geared towards developing algorithms and solutions for improving user perceived quality while making efficient use of available resources. Our goal is to provide the means for benchmarking such solutions in the context of multiple users accessing Video on Demand content while sharing a bottleneck link. For that purpose, we propose a quadratic problem formulation to compute the theoretical optimum in terms of adaptation strategies and corresponding segment downloads across multiple users under given bandwidth constraints. By aiming to maximize both service quality and fairness, we quantify and compare the impact of different fairness objectives (bandwidth fairness, pattern fairness, and session fairness) on resulting quality and achieved QoE fairness. Based on conducted simulations and parameter studies, our results demonstrate the benefits of optimizing for session fairness as compared to other approaches.

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

  %0 Conference Paper %1 info3-inproceedings-2018-37 %A Moldovan, Christian %A Skorin-Kapov, Lea %A Heegaard, Poul E. %A Hoßfeld, Tobias %B 30th International Teletraffic Congress (ITC 30) %C Vienna, Austria %D 2018 %P 6 %T Optimal Fairness and Quality in Video Streaming With Multiple Users %X With the majority of video distribution services relying on the HTTP adaptive streaming paradigm, a great deal of research is geared towards developing algorithms and solutions for improving user perceived quality while making efficient use of available resources. Our goal is to provide the means for benchmarking such solutions in the context of multiple users accessing Video on Demand content while sharing a bottleneck link. For that purpose, we propose a quadratic problem formulation to compute the theoretical optimum in terms of adaptation strategies and corresponding segment downloads across multiple users under given bandwidth constraints. By aiming to maximize both service quality and fairness, we quantify and compare the impact of different fairness objectives (bandwidth fairness, pattern fairness, and session fairness) on resulting quality and achieved QoE fairness. Based on conducted simulations and parameter studies, our results demonstrate the benefits of optimizing for session fairness as compared to other approaches.
• 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.
  • [ Abstract ]
  • [ BibTeX ]
  • [ 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.
• Practical QoE Evaluation of Adaptive Video Streaming. Surminski, Sebastian; Moldovan, Christian; Hoßfeld, Tobias. In Proceedings of the 19th International Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB). Erlangen, Germany, 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2018-7, address = {Erlangen, Germany}, author = {Surminski, Sebastian and Moldovan, Christian and Hoßfeld, Tobias}, booktitle = {Proceedings of the 19th International Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB)}, keywords = {dfg-sdn}, month = {02}, title = {Practical QoE Evaluation of Adaptive Video Streaming}, year = 2018 }

  %0 Conference Paper %1 info3-inproceedings-2018-7 %A Surminski, Sebastian %A Moldovan, Christian %A Hoßfeld, Tobias %B Proceedings of the 19th International Conference on Measurement, Modelling and Evaluation of Computing Systems (MMB) %C Erlangen, Germany %D 2018 %T Practical QoE Evaluation of Adaptive Video Streaming
• Towards Machine Learning-Based Optimal HAS. Sieber, Christian; Hagn, Korbinian; Moldovan, Christian; Hoßfeld, Tobias; Kellerer, Wolfgang. In arXiv preprint arXiv:1808.08065. 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @article{info3-article-2018-8, author = {Sieber, Christian and Hagn, Korbinian and Moldovan, Christian and Hoßfeld, Tobias and Kellerer, Wolfgang}, journal = {arXiv preprint arXiv:1808.08065}, keywords = {sys:hidden:article}, title = {Towards Machine Learning-Based Optimal HAS}, year = 2018 }

  %0 Journal Article %1 info3-article-2018-8 %A Sieber, Christian %A Hagn, Korbinian %A Moldovan, Christian %A Hoßfeld, Tobias %A Kellerer, Wolfgang %D 2018 %J arXiv preprint arXiv:1808.08065 %T Towards Machine Learning-Based Optimal HAS

• Viability of Wi-Fi Caches in an Era of HTTPS Prevalence. Moldovan, Christian. 2017 IEEE International Conference on Communications Workshops (ICC Workshops), Paris, France, 2017, May 25.
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-presentation-2017-12, address = {2017 IEEE International Conference on Communications Workshops (ICC Workshops), Paris, France}, author = {Moldovan, Christian}, keywords = {sys:hidden:presentation}, month = {05}, title = {Viability of Wi-Fi Caches in an Era of HTTPS Prevalence}, year = 2017 }

  %0 Generic %1 info3-presentation-2017-12 %A Moldovan, Christian %C 2017 IEEE International Conference on Communications Workshops (ICC Workshops), Paris, France %D 2017 %T Viability of Wi-Fi Caches in an Era of HTTPS Prevalence
• 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.
• Keep Calm and Don’t Switch: About the Relationship Between Switches and Quality in HAS. Moldovan, Christian. Genoa, Italy, 2017, September 8.
  • [ BibTeX ]
  • [ EndNote ]
  @misc{info3-presentation-2017-13, address = {Genoa, Italy}, author = {Moldovan, Christian}, booktitle = {29th International Teletraffic Congress (ITC 29)}, keywords = {sys:hidden:poster}, month = {09}, title = {Keep Calm and Don’t Switch: About the Relationship Between Switches and Quality in HAS}, year = 2017 }

  %0 Generic %1 info3-presentation-2017-13 %A Moldovan, Christian %B 29th International Teletraffic Congress (ITC 29) %C Genoa, Italy %D 2017 %T Keep Calm and Don’t Switch: About the Relationship Between Switches and Quality in HAS
• Saving Bandwidth by Limiting the Buffer Size in HTTP Adaptive Streaming. Surminski, Sebastian; Moldovan, Christian; Hoßfeld, Tobias. In MMBnet 2017 Proceedings of the 9th GI/ITG Workshop. Hamburg, Germany, 2017.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Video streaming is one of the most bandwidth-intensive applications on the Internet. In HTTP adaptive video streaming the video quality is selected according to the available bandwidth. To compensate bandwidth fluctuations, players use a buffer in order to ensure a smooth video output. On one hand, if the buffer runs empty, the video playback stops, which users experience as negative. On the other hand, if the user aborts video playback, the video in the buffer was unnecessarily transmitted, hence this bandwidth was wasted. In this paper, we present a study in which we investigate the behavior of two video players and different buffer configurations in real-world bandwidth scenarios. Thereby, we focus on the dimensioning of the buffer size and the tradeoff between wasted bandwidth and the playback quality

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

  %0 Conference Paper %1 info3-inproceedings-2017-27 %A Surminski, Sebastian %A Moldovan, Christian %A Hoßfeld, Tobias %B MMBnet 2017 Proceedings of the 9th GI/ITG Workshop %C Hamburg, Germany %D 2017 %T Saving Bandwidth by Limiting the Buffer Size in HTTP Adaptive Streaming %X Video streaming is one of the most bandwidth-intensive applications on the Internet. In HTTP adaptive video streaming the video quality is selected according to the available bandwidth. To compensate bandwidth fluctuations, players use a buffer in order to ensure a smooth video output. On one hand, if the buffer runs empty, the video playback stops, which users experience as negative. On the other hand, if the user aborts video playback, the video in the buffer was unnecessarily transmitted, hence this bandwidth was wasted. In this paper, we present a study in which we investigate the behavior of two video players and different buffer configurations in real-world bandwidth scenarios. Thereby, we focus on the dimensioning of the buffer size and the tradeoff between wasted bandwidth and the playback quality
• Keep Calm and Don’t Switch: About the Relationship Between Switches and Quality in HAS. Moldovan, Christian; Hagn, Korbinian; Sieber, Christian; Kellerer, Wolfgang; Hoßfeld, Tobias. In 29th International Teletraffic Congress (ITC 29), p. 6. Genoa, Italy, 2017.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Video streaming has established itself as the main method to consume multimedia content on the Internet. The most widespread technique is HTTP Adaptive Streaming which is used by large video service platforms such as YouTube and Netflix. In order to guarantee a high QoE, different adaptation strategies have been developed that lead to different video playout patterns. While some strategies may be more aggressive than others and often adapt the video quality, it is not clear which strategy is the best. In this paper, we want to identify the trade-off between the av- erage video quality and switches in the quality during playout. We do this with a user-centric view and try to optimize the adaptation depending on the user preference with a quadratic program. This work allows us to put existing and future video adaptation algorithms in perspective with respect to user preferences. Our results show that the video quality can already be increased greatly by allowing few switches while more switches lead to diminishing gains. This is a novel discovery that is important for user-centric QoE-management which is of high interest for ISPs and video service providers.

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

  %0 Conference Paper %1 info3-inproceedings-2017-26 %A Moldovan, Christian %A Hagn, Korbinian %A Sieber, Christian %A Kellerer, Wolfgang %A Hoßfeld, Tobias %B 29th International Teletraffic Congress (ITC 29) %C Genoa, Italy %D 2017 %P 6 %T Keep Calm and Don’t Switch: About the Relationship Between Switches and Quality in HAS %X Video streaming has established itself as the main method to consume multimedia content on the Internet. The most widespread technique is HTTP Adaptive Streaming which is used by large video service platforms such as YouTube and Netflix. In order to guarantee a high QoE, different adaptation strategies have been developed that lead to different video playout patterns. While some strategies may be more aggressive than others and often adapt the video quality, it is not clear which strategy is the best. In this paper, we want to identify the trade-off between the av- erage video quality and switches in the quality during playout. We do this with a user-centric view and try to optimize the adaptation depending on the user preference with a quadratic program. This work allows us to put existing and future video adaptation algorithms in perspective with respect to user preferences. Our results show that the video quality can already be increased greatly by allowing few switches while more switches lead to diminishing gains. This is a novel discovery that is important for user-centric QoE-management which is of high interest for ISPs and video service providers.
• Applicability and Limitations of a Simple WiFi Hotspot Model for Cities. Seufert, Michael; Moldovan, Christian; Burger, Valentin; Hoßfeld, Tobias. In 13th International Conference on Network and Service Management (CNSM). Tokio, Japan, 2017.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  Offloading mobile Internet data via WiFi has emerged as an omnipresent trend. WiFi networks are already widely deployed by many private and public institutions (e.g., libraries, cafes, restaurants) but also by commercial services to provide alternative Internet access for their customers and to mitigate the load on mobile networks. Moreover, smart cities start to install WiFi infrastructure for current and future civic services, e.g., based on sensor networks or the Internet of Things. A simple model for the distribution of WiFi hotspots in an urban environment is presented. The hotspot locations are modeled with a uniform distribution of the angle and an exponential distribution of the distance, which is truncated to the city limits. We compare the characteristics of this model in detail to the real distributions. Moreover, we show the applicability and the limitations of this model, and the results suggest that the model can be used in scenarios, which do not require an accurate spatial collocation of the hotspots, such as offloading potential, coverage, or signal strength.

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

  %0 Conference Paper %1 info3-inproceedings-2017-19 %A Seufert, Michael %A Moldovan, Christian %A Burger, Valentin %A Hoßfeld, Tobias %B 13th International Conference on Network and Service Management (CNSM) %C Tokio, Japan %D 2017 %T Applicability and Limitations of a Simple WiFi Hotspot Model for Cities %X Offloading mobile Internet data via WiFi has emerged as an omnipresent trend. WiFi networks are already widely deployed by many private and public institutions (e.g., libraries, cafes, restaurants) but also by commercial services to provide alternative Internet access for their customers and to mitigate the load on mobile networks. Moreover, smart cities start to install WiFi infrastructure for current and future civic services, e.g., based on sensor networks or the Internet of Things. A simple model for the distribution of WiFi hotspots in an urban environment is presented. The hotspot locations are modeled with a uniform distribution of the angle and an exponential distribution of the distance, which is truncated to the city limits. We compare the characteristics of this model in detail to the real distributions. Moreover, we show the applicability and the limitations of this model, and the results suggest that the model can be used in scenarios, which do not require an accurate spatial collocation of the hotspots, such as offloading potential, coverage, or signal strength.

• Modeling the YouTube Stack: from Packets to Quality of Experience. Wamser, Florian; Casas, Pedro; Seufert, Michael; Moldovan, Christian; Tran-Gia, Phuoc; Hoßfeld, Tobias. In Computer Networks, 109(2), pp. 211–224. 2016.
  • [ Abstract ]
  • [ BibTeX ]
  • [ EndNote ]
  • [ Download ]
  YouTube is one of the most popular and volume-dominant services in today’s Internet, and has changed the Web for ever. Consequently, network operators are forced to consider it in the design, deployment, and optimization of their networks. Taming YouTube requires a good understanding of the complete YouTube stack, from the network streaming service to the application itself. Understanding the interplays between individual YouTube functionalities and their implications for traffic and user Quality of Experience (QoE) becomes paramount nowadays. In this paper we characterize and model the YouTube stack at different layers, going from the generated network traffic to the QoE perceived by the users watching YouTube videos. Firstly, we present a network traffic model for the YouTube flow control mechanism, which permits to understand how YouTube provisions video traffic flows to users. Secondly, we investigate how traffic is consumed at the client side, deriving a simple model for the YouTube application. Thirdly, we analyze the implications for the end user, and present a model for the quality as perceived by them. This model is finally integrated into a system for real time QoE-based YouTube monitoring, highly useful to operators to assess the performance of their networks for provisioning YouTube videos. The central parameter for all the presented models is the buffer level at the YouTube application layer. This paper provides an extensive compendium of objective tools and models for network operators to better understand the YouTube traffic in their networks, to predict the playback behavior of the video player, and to assess how well they do it in the practice with the satisfaction of their customers watching YouTube.

  @article{info3-article-2016-6, abstract = {YouTube is one of the most popular and volume-dominant services in today’s Internet, and has changed the Web for ever. Consequently, network operators are forced to consider it in the design, deployment, and optimization of their networks. Taming YouTube requires a good understanding of the complete YouTube stack, from the network streaming service to the application itself. Understanding the interplays between individual YouTube functionalities and their implications for traffic and user Quality of Experience (QoE) becomes paramount nowadays. In this paper we characterize and model the YouTube stack at different layers, going from the generated network traffic to the QoE perceived by the users watching YouTube videos. Firstly, we present a network traffic model for the YouTube flow control mechanism, which permits to understand how YouTube provisions video traffic flows to users. Secondly, we investigate how traffic is consumed at the client side, deriving a simple model for the YouTube application. Thirdly, we analyze the implications for the end user, and present a model for the quality as perceived by them. This model is finally integrated into a system for real time QoE-based YouTube monitoring, highly useful to operators to assess the performance of their networks for provisioning YouTube videos. The central parameter for all the presented models is the buffer level at the YouTube application layer. This paper provides an extensive compendium of objective tools and models for network operators to better understand the YouTube traffic in their networks, to predict the playback behavior of the video player, and to assess how well they do it in the practice with the satisfaction of their customers watching YouTube.}, author = {Wamser, Florian and Casas, Pedro and Seufert, Michael and Moldovan, Christian and Tran-Gia, Phuoc and Hoßfeld, Tobias}, journal = {Computer Networks}, keywords = {can}, month = 11, number = 2, pages = {211-224}, title = {Modeling the YouTube Stack: from Packets to Quality of Experience}, volume = 109, year = 2016 }

  %0 Journal Article %1 info3-article-2016-6 %A Wamser, Florian %A Casas, Pedro %A Seufert, Michael %A Moldovan, Christian %A Tran-Gia, Phuoc %A Hoßfeld, Tobias %D 2016 %J Computer Networks %N 2 %P 211-224 %T Modeling the YouTube Stack: from Packets to Quality of Experience %V 109 %X YouTube is one of the most popular and volume-dominant services in today’s Internet, and has changed the Web for ever. Consequently, network operators are forced to consider it in the design, deployment, and optimization of their networks. Taming YouTube requires a good understanding of the complete YouTube stack, from the network streaming service to the application itself. Understanding the interplays between individual YouTube functionalities and their implications for traffic and user Quality of Experience (QoE) becomes paramount nowadays. In this paper we characterize and model the YouTube stack at different layers, going from the generated network traffic to the QoE perceived by the users watching YouTube videos. Firstly, we present a network traffic model for the YouTube flow control mechanism, which permits to understand how YouTube provisions video traffic flows to users. Secondly, we investigate how traffic is consumed at the client side, deriving a simple model for the YouTube application. Thirdly, we analyze the implications for the end user, and present a model for the quality as perceived by them. This model is finally integrated into a system for real time QoE-based YouTube monitoring, highly useful to operators to assess the performance of their networks for provisioning YouTube videos. The central parameter for all the presented models is the buffer level at the YouTube application layer. This paper provides an extensive compendium of objective tools and models for network operators to better understand the YouTube traffic in their networks, to predict the playback behavior of the video player, and to assess how well they do it in the practice with the satisfaction of their customers watching YouTube.
• Impact of Variances on the QoE in Video Streaming. Moldovan, Christian. ITC and IEEE Workshop on QoE Centric Management (QCMan), Würzburg, Germany, 2016, September 16.
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-presentation-2016-12, address = {ITC and IEEE Workshop on QoE Centric Management (QCMan), Würzburg, Germany}, author = {Moldovan, Christian}, keywords = {sys:hidden:presentation}, month = {09}, title = {Impact of Variances on the QoE in Video Streaming}, year = 2016 }

  %0 Generic %1 info3-presentation-2016-12 %A Moldovan, Christian %C ITC and IEEE Workshop on QoE Centric Management (QCMan), Würzburg, Germany %D 2016 %T Impact of Variances on the QoE in Video Streaming
• YouTube Can Do Better: Getting the Most Out of Video Adaptation. Moldovan, Christian. ITC and IEEE Workshop on QoE Centric Management (QCMan), Würzburg, Germany, 2016, September 16.
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-presentation-2016-11, address = {ITC and IEEE Workshop on QoE Centric Management (QCMan), Würzburg, Germany}, author = {Moldovan, Christian}, keywords = {sys:hidden:presentation}, month = {09}, title = {YouTube Can Do Better: Getting the Most Out of Video Adaptation}, year = 2016 }

  %0 Generic %1 info3-presentation-2016-11 %A Moldovan, Christian %C ITC and IEEE Workshop on QoE Centric Management (QCMan), Würzburg, Germany %D 2016 %T YouTube Can Do Better: Getting the Most Out of Video Adaptation
• Bridging the Gap between QoE and User Engagement in HTTP Video Streaming. Moldovan, Christian. 28th International Teletraffic Congress (ITC 28), Würzburg, Germany, 2016, September 14.
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-presentation-2016-13, address = {28th International Teletraffic Congress (ITC 28), Würzburg, Germany}, author = {Moldovan, Christian}, keywords = {sys:hidden:presentation}, month = {09}, title = {Bridging the Gap between QoE and User Engagement in HTTP Video Streaming}, year = 2016 }

  %0 Generic %1 info3-presentation-2016-13 %A Moldovan, Christian %C 28th International Teletraffic Congress (ITC 28), Würzburg, Germany %D 2016 %T Bridging the Gap between QoE and User Engagement in HTTP Video Streaming
• 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.
• QoE in Video Streaming - Example: Context Awareness. Moldovan, Christian. ITG 5.2.1 Workshop Performance Evaluation and Optimisation of Communication Networks, Hamburg, Germany, 2016, August 31.
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-presentation-2016-14, address = {ITG 5.2.1 Workshop Performance Evaluation and Optimisation of Communication Networks, Hamburg, Germany}, author = {Moldovan, Christian}, keywords = {sys:hidden:presentation}, month = {08}, title = {QoE in Video Streaming - Example: Context Awareness}, year = 2016 }

  %0 Generic %1 info3-presentation-2016-14 %A Moldovan, Christian %C ITG 5.2.1 Workshop Performance Evaluation and Optimisation of Communication Networks, Hamburg, Germany %D 2016 %T QoE in Video Streaming - Example: Context Awareness
• 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
• 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.
  • [ BibTeX ]
  • [ EndNote ]
  @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
• YouTube Can Do Better: Getting the Most Out of Video Adaptation. Moldovan, Christian; Sieber, Christian; Heegaard, Poul E.; Kellerer, Wolfgang; Hoßfeld, Tobias. In ITC and IEEE Workshop on QoE Centric Management (QCMan). 2016.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2016-28, author = {Moldovan, Christian and Sieber, Christian and Heegaard, Poul E. and Kellerer, Wolfgang and Hoßfeld, Tobias}, booktitle = {ITC and IEEE Workshop on QoE Centric Management (QCMan)}, keywords = {sys:hidden:inproceedings}, title = {YouTube Can Do Better: Getting the Most Out of Video Adaptation}, year = 2016 }

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

  %0 Conference Paper %1 info3-inproceedings-2016-29 %A Moldovan, Christian %A Hoßfeld, Tobias %B ITC and IEEE Workshop on QoE Centric Management (QCMan) %D 2016 %T Impact of Variances on the QoE in Video Streaming

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

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

  %0 Conference Paper %1 info3-inproceedings-2015-514 %A Seufert, Michael %A Burger, Valentin %A Wamser, Florian %A Tran-Gia, Phuoc %A Moldovan, Christian %A Hoßfeld, Tobias %B European Conference on Networks and Communications (EuCNC) %C Paris, France %D 2015 %T Utilizing Home Router Caches to Augment CDNs towards Information-Centric Networking %X To implement improved Quality of Service (QoS) and Quality of Experience (QoE) management for content-heavy services like video streaming, content has to be moved closer to the edge. The concept of information-centric networking (ICN) would be a prospective enabler but is currently not practically feasible yet. We propose a hierarchical caching architecture utilizing caches on home routers to augment existing content delivery network (CDN) infrastructure. This approach can be implemented via Software-defined Networking (SDN) and brings current CDNs closer towards ICN. Based on a simulation study, we confirm that our approach is able to serve content more locally, which results in QoS and QoE benefits for end users as well as inter-domain traffic savings for network operators.
• To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior. Moldovan, Christian. Third IFIP/IEEE International Workshop on Quality of Experience Centric Management, Ottawa, Canada, 2015, May 11.
  • [ BibTeX ]
  • [ EndNote ]
  @presentation{info3-presentation-2015-1, address = {Third IFIP/IEEE International Workshop on Quality of Experience Centric Management, Ottawa, Canada}, author = {Moldovan, Christian}, keywords = {sys:hidden:presentation}, month = {05}, title = {To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior}, year = 2015 }

  %0 Generic %1 info3-presentation-2015-1 %A Moldovan, Christian %C Third IFIP/IEEE International Workshop on Quality of Experience Centric Management, Ottawa, Canada %D 2015 %T To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior
• To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior. Hoßfeld, Tobias; Moldovan, Christian; Schwartz, Christian. In Third IFIP/IEEE International Workshop on Quality of Experience Centric Management. Ottawa, Canada, 2015.
  • [ BibTeX ]
  • [ EndNote ]
  @inproceedings{info3-inproceedings-2015-35, address = {Ottawa, Canada}, author = {Hoßfeld, Tobias and Moldovan, Christian and Schwartz, Christian}, booktitle = {Third IFIP/IEEE International Workshop on Quality of Experience Centric Management}, keywords = {sys:hidden:inproceedings}, month = {05}, title = {To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior}, year = 2015 }

  %0 Conference Paper %1 info3-inproceedings-2015-35 %A Hoßfeld, Tobias %A Moldovan, Christian %A Schwartz, Christian %B Third IFIP/IEEE International Workshop on Quality of Experience Centric Management %C Ottawa, Canada %D 2015 %T To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior