A comparison of server-based and receiver-based local recovery approaches for scalable reliable multicast

Local recovery approaches for reliable multicast have the potential to provide significant performance gains in terms of reduced bandwidth and delay, and higher system throughput. In this paper we examine two local recovery approaches-one server-based, and the other receiver-based, and compare their performance. The server-based approach makes use of specially designated hosts, called repair servers, co-located with routers inside the network. In the receiver-based approach, only the end hosts (sender and receivers) are involved in error recovery. Using analytical models, we first show that the two local recovery approaches yield significantly higher protocol throughput and lower bandwidth usage than an approach that does not use local recovery. Next, we demonstrate that server-based local recovery yields higher protocol throughput and lower bandwidth usage than receiver-based local recovery when the repair servers have processing power slightly higher than that of a receiver and several hundred kilobytes of buffer per multicast session.