A New Configuration Scheme for ACK Tree in Reliable Multicast Protocols

摘要

TCP is never used for scalable multicast because there are serious side effects such as ACK implosion when it is applied to multicast environment. To solve scalability, various solutions on the multicast transport have been proposed over the past 10-20 years. One of these solutions, tree-based ACK protocol is known to provide high scalability as well as reliability. We present in this paper a new hybrid scheme for configuring ACK trees for reliable multicast. Our scheme combines the advantages of both top-down and bottom-up approaches. First, it requires fewer messages than bottom-up approaches as the sender has to multicast the tree configuration messages. Second, our scheme allows the semi-concurrent creation of the ACK tree unlike top-down approaches. Finally, it can be adapted well to membership events such as JOIN and LEAVE. We also present a new repair node discovery algorithm for applying our hybrid scheme. Simulation results indicate that our scheme requires less messages than other ACK tree configuration schemes while being as fast as the fastest schemes.