Proxy-based single source application layer multicast media streaming

Abstract

Multicasting is the data distribution from one sender to a group of receivers. Traditionally multicasting is implemented at the network layer, in the way that routers perform membership management, maintain data delivery path, and replicate and forward data. IP Multicasting is the most efficient way for group data distribution. However, it has been shown that it is extremely difficult to deploy IP Multicasting at a large scale. There are scalability issues, deployment hurdles and marketing reasons. Therefore an alternative has been proposed to shift multicast support to the application layer. This approach expects end-hosts participating in the application to perform multicast functions. This is Application-Layer Multicasting (ALM). This thesis analyzes existing ALM protocols and proposes a proxy-based single source ALM protocol which targets media streaming applications, where latency is the overlay building metric. A single source real-time media streaming application is implemented based on this protocol. Some measurements are taken both on the intranet and on the Internet. The performance data provided by the tests show that the proposed protocol introduces acceptable control overheads. Finally, based on the experience with the implemented ALM system, recommendations for future work are provided.