Multicast Feedback Suppression Using Representatives

For a reliable ow controlled multicast transport protocol to scale it must avoid the feedback implosion problem particularly if the pro tocol targets arbitrarily large multicast groups communicating over lossy networks Most existing feedback control mechanisms based on probabilistic sup pression address the feedback implosion problem by suppressing feedback using timers based on round trip time RTT information This approach requires that all receivers compute RTT to the data source We present an algorithm whose major bene t derives from the fact that it does not need to compute RTT from receivers to the source and does not require knowledge of group membership or network topology We use a small set of representative receivers and probabilistic suppression to limit feedback We believe that our approach will perform well in real networks Simu lations using randomly generated network topologies of varying sizes with pessimistic network loss rates show that representatives considerably re duce the amount of feedback compared to a purely suppression based scheme For various multicast group sizes a few representatives can keep the amount of feedback low while not degrading feedback timeliness