Web Conferencing Traffic - An Analysis using DimDim as Example

In this paper, we present an evaluation of the Ethernet traffic for host and attendees of the popular opensource web conferencing system DimDim. While traditional Internet-centric approaches such as the MBONE have been used over the past decades, current trends for web-based conference systems make exclusive use of application-layer multicast. To allow for network dimensioning and QoS provisioning, an understanding of the underlying traffic characteristics is required. We find in our exemplary evaluations that the host of a web conference session produces a large amount of Ethernet traffic, largely due to the required control of the conference session, that is heavily-tailed distributed and exhibits additionally long-range dependence. For different groups of activities within a web conference session, we find distinctive characteristics of the generated traffic

Image Quality in Augmented Binocular Vision: QoE Approximations with QoS and EEG

Augmented reality (AR) applications become increasingly popular, however, little is known about how multimedia consumption interplays with the Quality of Experience (QoE) in these settings. We experimentally evaluate binocular vision augmentation with optical see-through devices by contrasting QoE, expressed by Mean Opinion Scores (MOS), with a ground truth reference data set. We find that the QoE in AR settings (i) is higher for small media impairments and lower for high impairment levels compared to opaque settings, (ii) exhibits an emerging quantifiable relationship with the QoE in traditional setups, (iii) can be approached with common objective image quality metrics as Quality of Service (QoS) factors, and (iv) exhibits a relationship between the Low Gamma frequency band levels determined with consumer-grade electroencephalograms (EEG) and image quality levels as rated by the participants

Video Traffic Characteristics of Modern Encoding Standards: H.264/AVC with SVC and MVC Extensions and H.265/HEVC

Video encoding for multimedia services over communication networks has significantly advanced in recent years with the development of the highly efficient and flexible H.264/AVC video coding standard and its SVC extension. The emerging H.265/HEVC video coding standard as well as 3D video coding further advance video coding for multimedia communications. This paper first gives an overview of these new video coding standards and then examines their implications for multimedia communications by studying the traffic characteristics of long videos encoded with the new coding standards. We review video coding advances from MPEG-2 and MPEG-4 Part 2 to H.264/AVC and its SVC and MVC extensions as well as H.265/HEVC. For single-layer (nonscalable) video, we compare H.265/HEVC and H.264/AVC in terms of video traffic and statistical multiplexing characteristics. Our study is the first to examine the H.265/HEVC traffic variability for long videos. We also illustrate the video traffic characteristics and statistical multiplexing of scalable video encoded with the SVC extension of H.264/AVC as well as 3D video encoded with the MVC extension of H.264/AVC

Performance Evaluation of Network Header Compression Schemes for UDP, RTP and TCP

Modern cellular networks utilising the Long–Term Evolution (LTE) set of standards face an ever–increasing demand for mobile data from connected devices. Header compression is employed to minimise the overhead for IP–based cellular network traffic.In this paper, we evaluate the three header compression implementations used by such networks with respect to their potential throughput increase and complexity for different mobile service scenarios. We compare RTP, UDP and TCP profile compressions regarding their compression gain and complexity. Specifically, we consider header compression as defined by (i) IP Header Compression (RFC 2507), (ii) Robust Header Compression version 1 (RFC 3095), and (iii) the recently updated Robust Header Compression version 2 (RFC 5225) with TCP/IP profile (RFC 6846).This paper presents the performance evaluation of these header compression schemes for UDP, RTP and TCP, for both IPv4 and IPv6 streams in error–free and error–prone scenarios. A comparison between the Robust Header Compression methods and IP Header Compression is also provided. Our results show that all implementations have great potential for saving bandwidth in IP–based wireless networks, even under varying channel conditions. We also present for the first time an analysis of certain RTP header fields which, depending on the transmission characteristics, could have high impact on the overall compression gain

Prediction of RoHCv1 and RoHCv2 compressor utilities for VoIP

Modern cellular networks utilising the long–term evolution (LTE) and the coming 5G set of standards face an ever–increasing demand for low–latency mobile data from connected devices. Header compression is employed to minimise the overhead for IP–based cellular network traffic, thereby decreasing the overall bandwidth usage and, subsequently, transmission delays. Here, we employ machine learning approaches for the prediction of Robust Header Compression version 1’s and version 2’s compression utility for VoIP transmissions, which allows the compression to dynamically adapt to varying channel conditions. We evaluate various regression models employing r2 and mean square error scores next to complexity (number of coefficients) based on an RTP specific training data set and separately captured live VoIP audio calls. We find that the proposed weighted Ridge regression model explains about at least 50 % of the observed results and the accuracy score may be as high as 94 % for some of the VoIP transmissions