VLDB 2026 Research / reviewers in the wild / expert
Florian Wamser
dblp:73/8197
· DBLP profile ↗
36ranked-venue papers
7as first author
7since 2021 · last 2024
0000-0002-0356-6291ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Computer networks · 15 · 5 first-author · 5 since 2021Graphics, computer vision, multimedia, augmented reality and games · 9 · 2 since 2021Human-computer interaction and ubiquitous computing · 5 · 1 since 2021Systems, architecture and hardware · 1Software engineering, systems software and programming languages · 1
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2024 | Untangling IoT Global Connectivity: The Importance of Mobile Signaling TrafficabstractIoT plays an important role in cellular networks, and its need for global connectivity is driving the rise of Global IoT Providers. These provide service by aggregating multiple mobile providers through roaming, complicating the understanding of the overall mobile ecosystem. This calls for lightweight monitoring solutions, which are crucial to meet the quality demanded by IoT services, and of automatic means to analyze the data, with the final goal to carry out economic and management activities. This paper provides insights from the study of two commercial, widespread IoT providers. We show how monitoring signaling traffic between mobile networks offers a unique opportunity to understand both the IoT customers’ characteristics and the network functioning. Leveraging clustering, we offer the first data-driven methodology to examine large IoT signaling datasets. By analyzing over 1.3 billion signaling dialogues across two providers, we identify common signaling profiles that depend on the specific IoT vertical, likely misconfigured devices, and sudden changes that indicate potential problems. This provides actionable insights for network management decisions and service improvements, and lays the groundwork for future research on IoT traffic modeling. Stefan Geißler, Andra Lutu, Florian Wamser, Thomas Favale, Viktoria Vomhoff, Michael Krolikowski, Marco Mellia, Diego Perino, Tobias Hoßfeld |
IEEE Trans. Netw. Serv. Manag. | 3 |
| 2024 | COBIRAS: Offering a Continuous Bit Rate Slide to Maximize DASH Streaming Bandwidth UtilizationabstractReaching close-to-optimal bandwidth utilization in dynamic adaptive streaming over HTTP (DASH) systems can, in theory, be achieved with a small discrete set of bit rate representations. This includes typical bit rate ladders used in state-of-the-art DASH systems. In practice, however, we demonstrate that bandwidth utilization, and consequently the quality of experience (QoE), can be improved by offering a continuous set of bit rate representations, i.e., a continuous bit rate slide (COBIRAS). Moreover, we find that the buffer fill behavior of different standard adaptive bit rate (ABR) algorithms is sub-optimal in terms of bandwidth utilization. To overcome this issue, we leverage COBIRAS’ flexibility to request segments with any arbitrary bit rate and propose a novel ABR algorithm MinOff , which helps maximizing bandwidth utilization by minimizing download off-phases during streaming. To avoid extensive storage requirements with COBIRAS and to demonstrate the feasibility of our approach, we design and implement a proof-of-concept DASH system for video streaming that relies on just-in-time encoding ( JITE ), which reduces storage consumption on the DASH server. Finally, we conduct a performance evaluation on our testbed and compare a state-of-the-art DASH system with few bit rate representations and our JITE DASH system, which can offer a COBIRAS, in terms of bandwidth utilization and video QoE for different ABR algorithms. Michael Seufert, Marius Spangenberger, Fabian Poignée, Florian Wamser, Werner Robitza, Christian Timmerer, Tobias Hoßfeld |
ACM Trans. Multim. Comput. Commun. Appl. | 4 |
| 2023 | Machine Learning Based Study of QoE Metrics in Twitch.tv Live StreamingabstractVideo streaming generates most network traffic in today’s Internet. For that reason, video on demand streaming is researched heavily in recent years, and many traffic monitoring mechanisms, flow and stream models, and models to predict the user perceived quality are well established. However, the quickly growing live streaming sector is not considered in these Quality of Experience models and not even the relation between network traffic and playback quality has been studied so far, forming a gap in literature. For that reason, we investigate Twitch.tv streaming as one of the largest live streaming platforms based on a large dataset and investigate the possibility to predict live streaming quality based on uplink request information. We apply approaches that are well studied for on demand streaming to predict quality changes, playback quality, and video interruption events as the most important metrics impairing user perceived quality. In this context, we answer whether these models are suitable for live streaming, if small changes are sufficient for satisfactory prediction results, or if fundamental changes and new models are required. Frank Loh, Kathrin Hildebrand, Florian Wamser, Stefan Geißler, Tobias Hoßfeld |
NOMS | 3 |
| 2023 | MVNOCoreSim: A Digital Twin for Virtualized IoT-Centric Mobile Core NetworksabstractThe rapid growth of connected devices has led to the implementation of Internet of Things (IoT)-centric platforms designed to provide connectivity for machine-to-machine-type communication. Specifically, mobile virtual network operators (MVNOs) provide global service for IoT use cases by leveraging roaming in readily deployed physical networks. This global deployment of connected devices poses a significant challenge regarding the operation of centralized core networks with respect to dimensioning, scaling, as well as system survivability in case of signaling incidents. Overload control mechanisms for IoT mobile networks offer a proactive solution for mitigating excessive signaling traffic from IoT devices in mobile core networks. However, global scaling and a heterogeneous composition of devices present network operators with additional challenges. To address these challenges, this work presents a detailed, protocol-level simulation framework of a real-world IoT MVNO core network. We present both models for the expected IoT signaling load and the processing of signaling messages based on measurements in a live, production environment as well as a dedicated testbed. Finally, we present a case study on various overload mechanisms and identify critical performance characteristics to compare their performance. The results of this study categorize overload control mechanisms and shed light on the necessity for MVNOs to deal with the upcoming IoT traffic by defining appropriate overload control mechanisms in mobile core networks to ensure network survivability under unforeseen conditions. Stefan Geißler, Florian Wamser, Wolfgang Bauer, Steffen Gebert, Samuel Kounev, Tobias Hoßfeld |
IEEE Internet Things J. | 2 |
| 2021 | Signaling Traffic in Internet-of-Things Mobile Networks
Stefan Geißler, Florian Wamser, Wolfgang Bauer, Michael Krolikowski, Steffen Gebert, Tobias Hoßfeld |
IM | 2 |
| 2021 | QoE Models in the Wild: Comparing Video QoE Models Using a Crowdsourced Data SetabstractCrowdsourced measurements solve the problem of being able to assess the performance of a communication network from an end-user perspective, but the new characteristics of the data pose new challenges for QoE modeling. In contrast to existing laboratory or network measurements, this type of measurement at the end user device primarily involves taking a large number of short sample measurements, which, however, are rich in measured parameters, including many user-, application-, and device-related parameters. To test the applicability and to facilitate the integration of such data, we applied four QoE models from the literature to 290k worldwide video streaming measurements from a commercial data set from August to October 2020. In this work, we will therefore first describe the crowdsourcing video streaming data set to provide insights into the properties of video streaming KPIs in the real world. Second, we run four popular QoE models using this data set, compare the resulting QoE scores, and derive the impact of individual KPIs for each model. We show that the models assess the QoE at least differently, but sometimes with contradicting statements. Reading this paper, it becomes evident that more work and subjective studies, based on real-world data like the one we have shown, are needed to extend the current QoE models. Anika Seufert, Florian Wamser, David Yarish, Hunter Macdonald, Tobias Hoßfeld |
QoMEX | 2 |
| 2021 | Energy-Aware Service Function Chain Embedding in Edge-Cloud Environments for IoT ApplicationsabstractThe implementation of Internet-of-Things (IoT) applications faces several challenges in practice, such as compliance with Quality-of-Service requirements, resource constraints, and energy consumption. In this context, the joint edge–cloud paradigm for IoT applications can resolve some of the issues arising in pure cloud computing scenarios, such as those related to latency, energy, or privacy. Therefore, an edge–cloud environment could be promising for resource and energy-efficient IoT applications that implement virtual network functions (VNFs) bound together into service function chains (SFCs). However, a resource and energy-efficient SFC placement requires smart SFC embedding mechanisms in the edge–cloud environment, as several challenges arise, such as IoT service chain modeling and evaluation, the tradeoff between resource allocation, energy efficiency and performance, and the resource dynamics. In this article, we address issues in modeling resource and energy utilization for IoT applications in edge–cloud environments. A smart traffic monitoring IP camera system is deployed as a use case for a realistic modeling of a service chain. The system is implemented in our testbed, which is designed and developed specifically to model and investigate the resource and energy utilization of SFC embedding strategies. A resource and energy-aware SFC strategy in the edge–cloud environment for IoT applications is then proposed. Our algorithm is able to cope with dynamic load and resource situations emerging from dynamic SFC requests. The strategy is evaluated systematically in terms of the acceptance ratio of SFC requests, resource efficiency and utilization, power consumption, and VNF migrations depending on the offered system load. Results show that our strategy outperforms some existing approaches in terms of resource and energy efficiency, thus it overcomes the relevant challenges from practice and meets the demands of IoT applications. Nguyen Huu Thanh 0001, Nguyen Trung Kien, Ngo Van Hoa, Thu-Huong Truong, Florian Wamser, Tobias Hoßfeld |
IEEE Internet Things J. | 5 |
| 2020 | Is the Uplink Enough? Estimating Video Stalls from Encrypted Network TrafficabstractToday’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. Frank Loh, Florian Wamser, Christian Moldovan, Bernd Zeidler, Dimitrios Tsilimantos, Stefan Valentin, Tobias Hoßfeld |
NOMS | 2 |
| 2019 | From click to playback: a dataset to study the response time of mobile YouTubeabstractResponding 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 at [8]. Frank Loh, Florian Wamser, Christian Moldovan, Bernd Zeidler, Tobias Hoßfeld, Dimitrios Tsilimantos, Stefan Valentin |
MMSys | 2 |
| 2019 | Internet-QoE 2019: 4th Internet-QoE Workshop on QoE-based Analysis and Management of Data Communication NetworksabstractAfter three highly successful editions of the Internet-QoE workshop organized at ACM SIGCOMM 2016, ACM SIGCOMM 2017, and IEEE ICDCS 2018, the goal of the fourth edition of the Internet-QoE workshop is to scale the concepts of Quality of Experience (user satisfaction, user engagement, and behavioral analysis) out of the lab studies context and bring it to the analysis and operation of distributed systems and communication networks, giving a user-centric perspective to the research performed by the MOBICOM community. By fostering an explicit and deep integration of the end-user directly into the design, analysis and management of large-scale operational networks, we expect to reduce the gap between QoE research and its application to future network management paradigms, as well as to provide a more targeted end-user perspective to the research on distributed communication systems. The 4th edition of Internet-QoE also focuses on novel end-user services enabled by next generation technologies such as immersive media (3D, Virtual Reality and Augmented Reality), self-driving cars, intelligent manufacturing systems, Industry 4.0 and tactile Internet, 5G ultra-low-latency mobile networks, and real-time applications. Pedro Casas, Florian Wamser, Fabián E. Bustamante, David R. Choffnes |
MobiCom | 2 |
| 2019 | User Behavior and Engagement of a Mobile Video Streaming User from Crowdsourced MeasurementsabstractMobile 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. Christian Moldovan, Florian Wamser, Tobias Hoßfeld |
QoMEX | 2 |
| 2018 | A Fair Share for All: Novel Adaptation Logic for QoE Fairness of HTTP Adaptive Video Streaming
Michael Seufert, Nikolas Wehner, Pedro Casas, Florian Wamser |
CNSM | 4 |
| 2018 | Beauty is in the Eye of the Smartphone Holder A Data Driven Analysis of YouTube Mobile QoE
Nikolas Wehner, Sarah Wassermann, Pedro Casas, Michael Seufert, Florian Wamser |
CNSM | 5 |
| 2018 | Enhancing Machine Learning Based QoE Prediction by Ensemble ModelsabstractThe number of smartphones connected to wireless networks and the volume of wireless network traffic generated by such devices have dramatically increased in the last few years, making it more challenging to tackle wireless network monitoring applications. The high-dimensionality of network data provided by current smartphone devices opens the door to the massive application of machine learning approaches to improve different wireless networking applications. In this paper we study the specific problem of Quality of Experience (QoE) prediction for popular smartphone apps, using machine learning models and in-smartphone measurements. We evaluate and compare different models for the analysis of smartphone generated data, including single models as well as machine learning ensembles such as bagging, boosting and stacking. Results suggest that, while decision-tree based models are the most accurate single models to predict QoE, ensemble learning models, and in particular stacking ones, are capable to significantly increase accuracy prediction and overall classification performance. Pedro Casas, Michael Seufert, Nikolas Wehner, Anika Seufert, Florian Wamser |
ICDCS | 5 |
| 2018 | Orchestration and Monitoring in Fog Computing for Personal Edge Cloud Service SupportabstractTo effectively support new cloud services and smart device accessibility, current Internet design must move away from its typical TCP/IP-based architecture and evolve towards new paradigms characterized by high degrees of freedom. In particular, Network Functions Virtualization and Software-Defined Networking have proven to be appropriate approaches to introducing edge-programmability. In this article we give an overview over the fog computing-architecture approach INPUT (In-Network Programmability for the next generation of Personal CloUd Service SupporT) with its implementation OpenVolcano, which uses the above approaches to promote future personal Internet cloud services at the network edge. Specifically, it enables computing and storage capabilities for edge network devices, provides a simple, private, programmable SDN-based Ethernet domain for end users and edge cloud services, IaaS and PaaS support with tight delay and performance constraints through templates. The focus of this work is on multi-service orchestration and monitoring, which is an essential core of any edge computing architecture. Florian Wamser, Chiara Lombardo, Constantinos Vassilakis, Lam Dinh-Xuan, Paolo Lago, Roberto Bruschi, Phuoc Tran-Gia |
LANMAN | 1 |
| 2018 | Demo: A wrapper for automated measurements with YouTube's native appabstractThis demo introduces a wrapper used for automated measurements of mobile video streaming in the Android YouTube app. The difference to traditional measurement techniques is that the measurement is done with the native YouTube app as it is provided in the Google Play Store. In addition to bandwidth or packet loss detection, the QoE of the video stream can be measured and quantified. For this, the amount of quality changes, the current playtime, the buffer level, and statistics like video and audio format are captured. Thus, detailed relationships between network parameters and streaming behavior based on many factors can be detected within the native app available in the Play Store. Frank Loh, Theodoros Karagkioules, Michael Seufert, Bernd Zeidler, Dimitrios Tsilimantos, Phuoc Tran-Gia, Stefan Valentin, Florian Wamser |
NOMS | 8 |
| 2018 | Streaming Characteristics of Spotify SessionsabstractInternet Service Providers need a thorough understanding of a service to maximize the Quality of Experience (QoE) of their customers by network management. Instead of quantifying the user satisfaction with long and cost-intensive subjective user studies, the QoE can often be estimated with the help of dedicated measurements of application and network parameters. We designed a QoE measurement tool for the popular audio streaming service Spotify that runs inside a Docker software container. The container is able to run headlessly as active measurement probe and emulates a user who is streaming audio files via Spotify. While streaming, network and application parameters are collected that have a high correlation to the user's QoE. The results of the measurements are used to characterize audio streaming in Spotify on application and network layer, and to evaluate important QoE factors. Anika Seufert, Florian Wamser, Thomas Gensler, Phuoc Tran-Gia, Michael Seufert, Pedro Casas |
QoMEX | 2 |
| 2018 | A Generic Approach to Video Buffer Modeling Using Discrete-Time AnalysisabstractThe large share of traffic in the Internet generated by video streaming services puts high loads on access and aggregation networks, resulting in high costs for the content delivery infrastructure. To reduce the bandwidth consumed while maintaining a high playback quality, video players use policies that control and limit the buffer level by using thresholds for pausing and continuing the video download. This allows shaping the bandwidth consumed by video streams and limiting the traffic wasted in case of playback abortion. Especially in mobile scenarios, where the throughput can be highly variant, the buffer policy can have a high impact on the probability of interruptions during video playback. To find the optimal setting for the buffer policy in each network condition, the relationship between the parameters of the buffer policy, the network throughput dynamics, and the corresponding video playback behavior needs to be understood. To this end, we model the video buffer as GI/GI/1 queue with pq -policy using discrete-time analysis. By studying the stochastic properties of the buffer-level distribution, we are able to accurately evaluate the impact of network and video bitrate dynamics on the video playback quality based on the buffer policy. We find a fundamental relationship between the bandwidth variation and the expected interarrival time of segments, meaning that overproportionately more bandwidth is necessary to prevent stalling events for high bandwidth variation. The proposed model further allows to optimize the trade-off between the traffic wasted in case of video abortion and video streaming quality experienced by the user. Valentin Burger, Thomas Zinner, Lam Dinh-Xuan, Florian Wamser, Phuoc Tran-Gia |
ACM Trans. Multim. Comput. Commun. Appl. | 4 |
| 2017 | Study on the accuracy of QoE monitoring for HTTP adaptive video streaming using VNFabstractThe fast growth of video streaming offers a potential market for video providers, which can significantly increase their revenues. In order to provide users a good experience, HTTP adaptive video streaming has been introduced to adapt the video quality to the network conditions. Nevertheless, it is still difficult for the network operators to assess the actual video quality on the device of the users and therefore they may not react to improve the service on the network. In this work, we propose a Virtual Network Function (VNF) to monitor the Quality of Experience (QoE) for online video service in the network. To conduct the study, on the one hand, we design a VNF monitoring to measure the video quality and estimate the QoE at the client machine. On the other hand, we place the function in two locations nearby and far away from the user to analyze the impact of geographical placement of the VNF on its performance. Our findings show that with respect to function placement, the VNF has high accuracy in estimating the QoE if it is deployed at the edge network close to the user. However, the VNF does not perform well when it operates far away from the users, e.g., at data centers. These insights help network vendors to more closely monitor the quality of the videos streamed to their customers. Lam Dinh-Xuan, Michael Seufert, Florian Wamser, Phuoc Tran-Gia |
IM | 3 |
| 2017 | Dynamic cloud service placement for live video streaming with a remote-controlled droneabstractIn this demonstration we will show the prospects of dynamic cloud service placement. A cloud service is implemented that manages real-time video streaming and real-time control commands for a remote controlled drone. The requirements for this cloud service are groundbreaking because the image transfer and the control commands should be transmitted in real time that the drone can be controlled smoothly by a user. The goal is to improve user QoE for streaming services and real-time control by cloud service migrations, respecting the concept of dynamic Edge Computing by means of moving computing and monitoring applications on demand close to the user and the end device. Florian Wamser, Frank Loh, Michael Seufert, Phuoc Tran-Gia, Roberto Bruschi, Paolo Lago |
IM | 1 |
| 2017 | Edgenetworkcloudsim: Placement of service chains in edge clouds using networkcloudsimabstractEdge cloud computing is a trending paradigm, which extends cloud computing by additionally utilizing computing resources at the network edge, e.g., at mobile base stations. Especially personalized services can be instantiated or migrated close to end users, which improves the latency and supports user mobility. However, the placement of the service chains is crucial for the performance of the services and the energy consumption of the edge cloud platform, and appropriate algorithms have to be designed. To support the simulative performance evaluation of such algorithms, EdgeNetworkCloudSim was developed. It is an extension of NetworkCloudSim, and allows to simulate and evaluate the orchestration and consolidation of service chains in an edge network cloud. Michael Seufert, Brice Kamneng Kwam, Florian Wamser, Phuoc Tran-Gia |
NetSoft | 3 |
| 2017 | Predicting QoE in cellular networks using machine learning and in-smartphone measurementsabstractMonitoring the Quality of Experience (QoE) undergone by cellular network customers has become paramount for cellular ISPs, who need to ensure high quality levels to limit customer churn due to quality dissatisfaction. This paper tackles the problem of QoE monitoring, assessment and prediction in cellular networks, relying on end-user device (i.e., smart-phone) QoS passive traffic measurements and QoE crowdsourced feedback. We conceive different QoE assessment models based on supervised machine learning techniques, which are capable to predict the QoE experienced by the end user of popular smartphone apps (e.g., YouTube and Facebook), using as input the passive in-device measurements. Using a rich QoE dataset derived from field trials in operational cellular networks, we benchmark the performance of multiple machine learning based predictors, and construct a decision-tree based model which is capable to predict the per-user overall experience and service acceptability with a success rate of 91% and 98% respectively To the best of our knowledge, this is the first paper using end-user, in-device passive measurements and machine learning models to predict the QoE of smartphone users in operational cellular networks. Pedro Casas, Alessandro D'Alconzo, Florian Wamser, Michael Seufert, Bruno Gardlo, Anika Seufert, Phuoc Tran-Gia, Raimund Schatz |
QoMEX | 3 |
| 2017 | Unsupervised QoE field study for mobile YouTube video streaming with YoMoAppabstractYoMoApp (YouTube Monitoring App) is an Android app to monitor mobile YouTube video streaming on both application- and network-layer. Additionally, it allows to collect subjective Quality of Experience (QoE) feedback of end users. During the development of the app, the stable versions of YoMoApp were already available in the Google Play Store, and the app was downloaded, installed, and used on many devices to monitor streaming sessions. As the app was not advertised in special campaigns or used for dedicated QoE studies, the monitored streaming sessions of this period compose the data set of a large unsupervised field study. The collected data set is evaluated to characterize current mobile YouTube streaming on both application and network layers. Furthermore, the problems and methodology to obtain QoE results from such unsupervised field study are discussed together with the actual QoE results. Correlations between QoE factors are investigated, and the QoE of clusters of similar streaming sessions is analyzed. Michael Seufert, Nikolas Wehner, Florian Wamser, Pedro Casas, Alessandro D'Alconzo, Phuoc Tran-Gia |
QoMEX | 3 |
| 2017 | Analytical Model for SDN Signaling Traffic and Flow Table Occupancy and Its Application for Various Types of TrafficabstractSoftware defined networking (SDN) has emerged as a promising networking paradigm overcoming various drawbacks of current communication networks.The control and data plane of switching devices is decoupled and control functions are centralized at the network controller. In SDN, each new flow introduces additional signaling traffic between the switch and the controller. Based on this traffic, rules are created in the flow table of the switch, which specify the forwarding behavior. To avoid table overflows, unused entries are removed after a predefined time-out period. Given a specific traffic mix, the choice of this time-out period affects the tradeoff between signaling rate and table occupancy. As a result, network operators have to adjust this parameter to enable a smooth and efficient network operation. Due to the complexity of this problem caused by the various traffic flows in a network, a suitable abstraction is necessary in order to derive valid parameter values in time. The contribution of this paper is threefold. First, we formulate a simple analytical model that allows optimizing the network performance with respect to the table occupancy and the signaling rate. Second, we validate the model by means of simulation. Third, we illustrate the impact of the time-out period on the signaling traffic and the flow table occupancy for different data-plane traffic mixes and characteristics. This includes scenarios with single application instances, as well as multiple application instances of different application types in an SDN-enabled network. Christopher Metter, Michael Seufert, Florian Wamser, Thomas Zinner, Phuoc Tran-Gia |
IEEE Trans. Netw. Serv. Manag. | 3 |
| 2016 | Analytic model for SDN controller traffic and switch table occupancyabstractSoftware Defined Networking (SDN) is a major paradigm in the field of current communication networks. SDN is used as the basis of many new networks although few performance models are available in the literature, and the majority of performance evaluations are based primarily on practical measurements. To fill this gap, we develop an analytical model to assess SDN control plane traffic as well as the occupancy of the flow table of an SDN switch. The contribution of this work is the formulation of the model for the performance-decisive parameters control-plane traffic and flow table occupancy and the application of the model for different data plane traffic characteristics. In the end, there is a discussion about the setting of time-out values for storing flow entries in the switch flow table depending on the traffic characteristics in the data plane. The trade-off between the signaling traffic in the control plane and the occupancy of the flow table is discussed to minimize both. Christopher Metter, Michael Seufert, Florian Wamser, Thomas Zinner, Phuoc Tran-Gia |
CNSM | 3 |
| 2016 | Load dynamics of a multiplayer online battle arena and simulative assessment of edge server placementsabstractFree-to-play models, streaming of games and eSports are reasons for online gaming to grow in popularity recently. On the forefront are multiplayer online battle arenas, which gain high popularity by introducing a competitive format that is easy to access and requires cooperation and team play. These games highly rely on fast reaction of the players, which makes latency the key performance indicator of such applications. To obtain low latency, this paper proposes moving game servers close to players towards the edge of the network. The performance of such mechanism highly depends on the geographic distribution of players. By analyzing match histories and statistics, we develop models for the arrival process and location of game requests. This allows us to evaluate the performance of edge server resource migration policies in an event based simulation. Our results show that a high number of edge servers is preferable compared to few larger edge servers to reduce the latency of players. This supports approaches that allow deploying virtual server instances in the back-haul. Valentin Burger, Jane Frances Pajo, Odnan Ref Sanchez, Michael Seufert, Christian Schwartz, Florian Wamser, Franco Davoli, Phuoc Tran-Gia |
MMSys | 6 |
| 2016 | Modeling the YouTube stack: From packets to quality of experience
Florian Wamser, Pedro Casas, Michael Seufert, Christian Moldovan, Phuoc Tran-Gia, Tobias Hoßfeld |
Comput. Networks | 1 |
| 2016 | Next to You: Monitoring Quality of Experience in Cellular Networks From the End-DevicesabstractA quarter of the world population will be using smartphones to access the Internet in the near future. In this context, understanding the quality of experience (QoE) of popular apps in such devices becomes paramount to cellular network operators, who need to offer high-quality levels to reduce the risks of customers churning for quality dissatisfaction. In this paper, we address the problem of QoE provisioning in smartphones from a double perspective, combining the results obtained from subjective laboratory tests with end-device passive measurements and QoE crowd-sourced feedback obtained in operational cellular networks. The study addresses the impact of both access bandwidth and latency on the QoE of five different services and mobile apps: YouTube, Facebook, Web browsing through Chrome, Google Maps, and WhatsApp. We evaluate the influence of both constant and dynamically changing network access conditions, tackling in particular the case of fluctuating downlink bandwidth, which is typical in cellular networks. As a main contribution, we show that the results obtained in the laboratory are highly applicable in the live scenario, as mappings track the QoE provided by users in real networks. We additionally provide hints and bandwidth thresholds for good QoE levels on such apps, as well as discussion on end-device passive measurements and analysis. The results presented in this paper provide a sound basis to better understand the QoE requirements of popular mobile apps, as well as for monitoring the underlying provisioning network. To the best of our knowledge, this is the first paper providing such a comprehensive analysis of QoE in mobile devices, combining network measurements with users QoE feedback in laboratory tests, and operational networks. Pedro Casas, Michael Seufert, Florian Wamser, Bruno Gardlo, Andreas Sackl, Raimund Schatz |
IEEE Trans. Netw. Serv. Manag. | 3 |
| 2015 | Taming QoE in cellular networks: From subjective lab studies to measurements in the fieldabstractA quarter of the world population will be using smartphones to access the Internet in the near future. In this context, understanding the Quality of Experience (QoE) of popular apps in such devices becomes paramount to cellular network operators, who need to offer high quality levels to reduce the risks of customers churning for quality dissatisfaction. In this paper we address the problem of QoE provisioning in smartphones from a double perspective, combining the results obtained from subjective lab tests with end-device passive measurements and QoE crowd-sourced feedback obtained in operational cellular networks. The study addresses the impact of the downlink bandwidth on the QoE of three popular smartphone apps: YouTube, Facebook and Google Maps. As a main contribution, we show that the results obtained in the lab are highly applicable in the live scenario, as mappings track the QoE provided by users in real networks. We additionally provide hints and bandwidth thresholds for good QoE levels on such apps, as well as discussion on end-device passive measurements and analysis. The results presented in this paper provide a sound basis to better understand the QoE requirements of popular mobile apps, as well as for monitoring the underlying provisioning network. To the best of our knowledge, this is the first paper providing such a comprehensive analysis of QoE in mobile devices, combining network measurements with users QoE feedback in lab tests and operational networks. Pedro Casas, Bruno Gardlo, Michael Seufert, Florian Wamser, Raimund Schatz |
CNSM | 4 |
| 2015 | YouTube QoE on mobile devices: Subjective analysis of classical vs. adaptive video streamingabstractYouTube is the most popular service in the Internet and is increasingly consumed on mobile devices. With emerging adaptive video streaming technology, the question arises whether it should be also employed in the mobile context, which shows different characteristics in terms of display sizes and reliability of Internet connection. This paper compares YouTube QoE on mobile devices for both classical and adaptive video streaming based on a subjective lab experiment, in which different network conditions were emulated. Our results show that adaptive video streaming provides almost excellent results for the poorest network conditions. Thereby, it clearly outperforms classical video streaming, and thus, should be considered to achieve higher QoE in future mobile streaming applications. Michael Seufert, Florian Wamser, Pedro Casas, Ralf Irmer, Phuoc Tran-Gia, Raimund Schatz |
IWCMC | 2 |
| 2015 | Poster: Understanding YouTube QoE in Cellular Networks with YoMoApp: A QoE Monitoring Tool for YouTube MobileabstractThe performance of YouTube in cellular networks is crucial to network operators, who try to find a trade-off between cost-efficient handling of the huge traffic amounts and high perceived end-user Quality of Experience (QoE). In this paper we present YoMoApp (YouTube Performance Monitoring Application), an Android application which passively monitors key performance indicators (KPIs) of YouTube adaptive video streaming on end-user smartphones. The monitored KPIs (i.e., player state/events, re-buffering, and video quality levels) can be used to analyze the QoE of mobile YouTube video sessions. YoMoApp is a valuable tool to assess the performance of cellular networks with respect to YouTube traffic, as well as to develop optimizations and QoE models for mobile HTTP adaptive streaming. We try YoMoApp through real subjective QoE lab tests showing that the tool is accurate to capture the experience of end-users watching YouTube on smartphones. Florian Wamser, Michael Seufert, Pedro Casas, Ralf Irmer, Phuoc Tran-Gia, Raimund Schatz |
MobiCom | 1 |
| 2014 | Dynamic application-aware resource management using Software-Defined Networking: Implementation prospects and challengesabstractToday's Internet does not provide an exchange of information between applications and networks, which may result in poor application performance. Concepts such as application-aware networking or network-aware application programming try to overcome these limitations. The introduction of Software-Defined Networking (SDN) opens a path towards the realization of an enhanced interaction between networks and applications. Hence, a more dynamic and demand-based allocation of network resources to heterogeneous applications can be realized. The implementation of the resource management action, however, may have an impact on the data transport and application quality. This paper summarizes resource management mechanisms provided by current SDN approaches based on OpenFlow and exemplary evaluates implementation prospects and challenges. Thomas Zinner, Michael Jarschel, Andreas Blenk, Florian Wamser, Wolfgang Kellerer |
NOMS | 4 |
| 2014 | Demonstrating the prospects of dynamic application-aware networking in a home environmentabstractNo abstract available. Florian Wamser, Thomas Zinner, Lukas Iffländer, Phuoc Tran-Gia |
SIGCOMM | 1 |
| 2010 | Advanced interference mitigation with frequency reuse schemes in the IEEE 802.16m uplinkabstractFractional frequency reuse is one of the key interference mitigation schemes of the IEEE 802.16m draft standard. This paper proposes a resource allocation strategy for the uplink fractional frequency reuse in the variant soft frequency reuse. Soft frequency reuse means that the resources of every sector are separated into a home partition and two side partitions. While resources of the home partition may be allocated to all users, resources of the side partitions are available for cell center users only. The main contribution of this paper is to use the most robust and power-efficient modulation and coding schemes on the side partitions as long as resources are available. A simulation study shows that with non-saturated users the system capacity can be increased when preferring power-efficient modulation and coding schemes on the side partitions. Florian Wamser, David Mittelstädt, Dirk Staehle, Phuoc Tran-Gia |
MSWiM | 1 |
| 2010 | Soft Frequency Reuse in the Uplink of an OFDMA NetworkabstractThe challenges with deploying a cellular wireless communication network with static frequency reuse in an interference limited environment is that for highly loaded cells, significant regions of coverage will experience high interference levels, resulting in unserviceable low signal-to-interference values. Therefore, interference mitigation approaches as adaptive fractional frequency reuse are considered to tackle the problem. In this paper, different strategies for user and resource allocation are evaluated along with fractional frequency reuse schemes. In contrast to downlink scenarios, we investigate the performance of the OFDMA uplink. It is shown that soft frequency reuse is well-performing in the uplink although it is easy to deploy since it does not rely on resource coordination. Florian Wamser, David Mittelstädt, Dirk Staehle |
VTC Spring | 1 |
| 2009 | Traffic Measurement and Analysis of a Broadband Wireless Internet AccessabstractThe increasing broadband wireless Internet usage and the limited wireless resources require a careful network management and optimization of the wireless Internet Service Providers (ISPs). Unfortunately, those providers often just have statistics about the overall usage and limited knowledge about the detailed application distribution as well as the traffic characteristics. In this paper we present user and traffic characteristics measured at a broadband wireless Internet access. The results show that the applications change quickly but the general characteristics like packet size and TCP/UDP percentage have not changed during the last years. Rastin Pries, Florian Wamser, Dirk Staehle, Klaus Heck, Phuoc Tran-Gia |
VTC Spring | 2 |