Video Communications Over IP/ATM Networks Implementation Issues and Performance

Abstract

Many recent studies have been conducted involving the transport of constant and variable bit rate MPEG-2 video in Asynchronous Transfer Mode (ATM) networks; however, many of these studies have considered fairly homogeneous scenarios in which the only other traffic present in the ATM network, if any, are other MPEG-2 video sources. In this study the traffic pattern of MPEG-2 video communications in an ATM network under heavily loaded network conditions, in which the generated traffic sources are bursty in nature, is considered. To complete the study an experimental VoD testbed, developed as part of a collaborative research effort between the Communications Research Centre of Canada (CRC), Nortel and the University of Ottawa, was employed. To determine the characteristics of the MPEG-2 video traffic generated by the VoD application in the ATM network in the presence of other traffic, cell interarrivai time measurements were considered. Results obtained show that the end-to-end flow control implemented in the application layer in the VoD system and the traffic controls implemented intermediate network elements (e.g., routers, switches) have significant impacts on the characteristics of the MPEG-2 traffic carried in the ATM network. Moreover, the impact of the intermediate network elements on the characteristics of the MPEG-2 traffic increases with the amount of non-MPEG-2 video traffic present in the network.