Andreas Aurelius

Analysis and characterization of IPTV user behavior

Today, due to the fast development of Internet Protocol TV (IPTV), which is the combination of IP technology and two-way broadband networks, the telecom industry is undergoing fundamental changes. Network operators and service providers around the world are making significant investments in order to deliver digital video content to their subscribers. Video puts very high demands on the network and utilizes a large fraction of the available bandwidth. Consequently, it is important to understand the technical demands that IPTV requires of the network infrastructure as well as user behavior and network traffic patterns to further optimize network operation. The purpose of this paper is to characterize IPTV traffic and study end user behavior by analyzing and modeling IPTV traffic collected from a Swedish municipal network. The focus of the measurements was put on Internet Group Management Protocol (IGMP) packets. Apart from the measurement results and analysis, the paper provides background information about the technologies and issues of IPTV. IP multicast which is used for transferring Live TV content is based on the concept of a group. IGMP is used to manage the membership of multicast groups. Based on this information, traffic parameters for analysis were chosen and measured.

Analysis of user demand patterns and locality for YouTube traffic

Video content, of which YouTube is a major part, constitutes a large share of residential Internet traffic. In this paper, we analyse the user demand patterns for YouTube in two metropolitan access networks with more than 1 million requests over three consecutive weeks in the first network and more than 600,000 requests over four consecutive weeks in the second network. In particular we examine the existence of “local interest communities”, i.e. the extent to which users living closer to each other tend to request the same content to a higher degree, and it is found that this applies to (i) the two networks themselves; (ii) regions within these networks (iii) households with regions and (iv) terminals within households. We also find that different types of access devices (PCs and handhelds) tend to form similar interest communities. It is also found that repeats are (i) “self-generating” in the sense that the more times a clip has been played, the higher the probability of playing it again, (ii) “long-lasting” in the sense that repeats can occur even after several days and (iii) “semiregular” in the sense that replays have a noticeable tendency to occur with relatively constant intervals. The implications of these findings are that the benefits from large groups of users in terms of caching gain may be exaggerated, since users are different depending on where they live and what equipment they use, and that high gains can be achieved in relatively small groups or even for individual users thanks to their relatively predictable behaviour.

Full-reference video quality metric assisted the development of no-reference bitstream video quality metrics for real-time network monitoring

High-quality video is being increasingly delivered over Internet Protocol networks, which means that network operators and service providers need methods to measure the quality of experience (QoE) of the video services. In this paper, we propose a method to speed up the development of no-reference bitstream objective metrics for estimating QoE. This method uses full-reference objective metrics, which makes the process significantly faster and more convenient than using subjective tests. In this process, we have evaluated six publicly available full-reference objective metrics in three different databases, the EPFL-PoliMI database, the HDTV database, and the Live Video Wireless database, all containing transmission distortions in H.264 coded video. The objective metrics could be used to speed up the development process of no-reference real-time video QoE monitoring methods that are receiving great interest from the research community. We show statistically that the full-reference metric Video Quality Metric (VQM) performs best considering all the databases. In the EPFL-PoliMI database, SPATIAL MOVIE performed best and TEMPORAL MOVIE performed worst. When transmission distortions are evaluated, using the compressed video as the reference provides greater accuracy than using the uncompressed original video as the reference, at least for the studied metrics. Further, we use VQM to train a lightweight no-reference bitstream model, which uses the packet loss rate and the interval between instantaneous decoder refresh frames, both easily accessible in a video quality monitoring system.

Evaluation of video quality metrics on transmission distortions in H.264 coded video

The development of high-speed access networks has enabled a variety of video delivery alternatives over the Internet, for example IPTV and peer-to-peer based video services as Voddler. Consequently, the development of real-time video QoE monitoring methods is receiving large attention in the research community. We believe that the good performing objective metrics using reference information could be used to speed up the development process of real-time video QoE monitoring methods. Thus in this paper we study the accuracy of full-reference objective methods for assessing the quality degradation due to the transmission distortions. We evaluated several well-known publicly-available full-reference objective metrics on the freely available EPFL-PoliMI (Ecole Polytechnique Fédérale de Lausanne and Politecnico di Milano) video quality assessment database, which was specifically designed for the evaluation of transmission distortions. The full-reference metrics are usually evaluated using a reference which is uncompressed. Instead, we study the performance of the metrics when the reference videos are lightly compressed to ensure high quality.

Youtube traffic content analysis in the perspective of clip category and duration

In this work, we study YouTube traffic characteristics in a medium-sized Swedish residential municipal network that has - 2600 mainly FTTH broadband-connected households. YouTube traffic analyses were carried out in the perspective of video clip category and duration, in order to understand their impact on the potential local network caching gains. To the best of our knowledge, this is the first time systematic analysis of YouTube traffic content in the perspective of video clip category and duration in a residential broadband network. Our results show that the requested YouTube video clips from the end users in the studied network were imbalanced in regarding the video categories and durations. The dominating video category was Music, both in terms of the total traffic share as well as the contribution to the overall potential local network caching gain. In addition, most of the requested video clips were between 2-5 min in duration, despite video clips with durations over 15 min were also popular among certain video categories, e.g. film videos.

Triangulation as a way to validate and deepen the knowledge about user behavior : A comparison between questionnaires, diaries and traffic measurements

The transformations of people’s relations to media content, technologies and institutions raise new methodological challenges and opportunities for audience research. This edited volume aims at contributing to the development of the repertoire of methods and methodologies for audience research by reviewing and exemplifying approaches that have been stimulated by the changing conditions and practices of audiences. The contributions address a range of issues and approaches related to the diversification, integration and triangulation of methods for audience research, to the gap between the researched and the researchers, to the study of online social networks, and to the opportunities brought about by Web 2.0 technologies as research tools.Triangulation as a way to validate and deepen the knowledge about user behavior : A comparison between questionnaires, diaries and traffic measurements

How much of the bandwidth do we actually use? An investigation of residential access traffic load

Internet traffic from a fibre based residential access network is investigated concerning traffic volumes and link load. Also the cost of the services is analyzed. We show that 1 Mbps accesses subscribers maintain high loads, and that the price they pay per GB used is five times higher than the one paid by 100 Mbps access subscribers.

Leveraging network and traffic measurements for content distribution and interpersonal communication services with sufficient quality

In this paper, we discuss research problems for enabling content distribution and supporting real-time interpersonal communication services (e.g. voice and video) over best effort networks with sufficient quality. We take a practical view of content distribution and quality, and this is the reason for the term “sufficient”. We argue that the understanding of quality as perceived by the user is a key factor in this context, but also that the understanding of context dependence is a key factor for delivering services which are “good enough” to make the user satisfied. We base our assumptions upon results from the Celtic TRAMMS project, and we describe how to leverage upon the framework for traffic measurements that was built up in that project. Moreover, we identify key technological components that are common for optimization of content delivery and real-time interpersonal communication services such as VoIP and videoconferencing. We also describe how the research problems stated will be tackled in the newly started IPNQSIS project.