Study of MPEG-2 video traffic in a multimedia LAN/ATM internetwork system

Many 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 requirements of supporting MPEG-2 video communications in an ATM network under unloaded and heavily loaded network conditions, in which the generated traffic sources are bursty in nature, are considered. To complete the study an experimental video on demand (VoD) testbed, developed as part of a collaborative research effort between the Communications Research Center 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 interarrival time measurements and cell rate snapshots at the ATM cell level were considered. Results obtained show that the end-to-end flow control implemented in the application layer in the video-on-demand (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.