MODELLING AND SIMULATION STUDIES OF A VIDEO ON DEMAND SERVICE OVER INTERCONNECTED LAN AND ATM NETWORKS

Abstract

High speed networks employing ATM technology have become popular as a result of increased traffic load and the transfer of multimedia information on computer networks. However, for existing equipment with small buffer sizes within these high speed networks, cell loss is unavoidable when the buffers overflow. Thus, it is necessary to introduce appropriate mechanisms into the network so as to prevent or reduce the effect of such overflows. The first part of this thesis gives an analysis of the performance issues of such a buffer-limited network, and provides a traffic shaping solution through the introduction of a router. Two scenarios are studied using this mechanism, and it is found that although traffic shaping can reduce cell loss, it can cause low throughput and increased end-to-end delays. The second part of this thesis studies a buffer management scheme that allocates buffers on demand based on feedback information from each intermediate ATM switch. This resulted in a significant reduction in the number of cell losses, although improvement in throughput is minimal. It is shown that ATM technology is one technology that can provide an efficient high speed data network when coupled with good network management.