Avoiding Unnecessary Congestion Responses in Layered Multicast with Heterogeneous Receivers

Receiver-driven layered multicast has been designed to support scalable multimedia applications and very recently used to support bulk file transfers. Layered multicast congestion control assumes that all the receivers behind a bottleneck are equally able to subscribe to a particular number of cumulative layers. This paper explores the requirement placed on heterogeneous receivers behind a bottleneck router link. In such a scenario, leaving a layer by a less capable receiver (as a result of a congestion response) leads to resource underutilization in multicasting. Three approaches to a solution to the problem are discussed together with their limitations. Index Terms scalable content, layered multicast, traffic prioritization, shared feedback announcements, explicit congestion notification