SRMT-a scalable and reliable multicast transport protocol

Many applications require reliable multicast for data transmission. A number of protocols have been proposed previously for large-scale reliable multicast. Unfortunately these protocols may suffer from the length of the retransmission paths between the source and receivers which yields a very high cost for retransmissions. Therefore we propose the SRMT protocol (scalable and reliable multicast transport protocol) as an alternative to existing approaches. In SRMT an overlay network consisting of SRMT nodes is built on top of existing multicast routing protocols. Retransmissions take place between neighbouring SRMT nodes in the multicast tree. A simple analysis shows the advantages of our method compared to two existing protocols. In the case of networks with high loss probabilities our approach is the only one applicable. For small loss probabilities our protocol (in an example) yields a reduction of more than 65% of the retransmission load caused by the other methods.