SomeCast. A paradigm for real-time adaptive reliable multicast

SomeCast is a novel paradigm for the reliable multicast of real time data to a large set of receivers. SomeCast is receiver-initiated and thus scalable in the number of receivers, the diverse characteristics of paths between senders and receivers, and the dynamic conditions of such paths. SomeCast enables receivers to dynamically adjust the rate at which they receive multicast information to enable the satisfaction of their QoS constraints. This is done by enabling a receiver to join SOME number of concurrent multiCAST sessions, whereby each session delivers a portion of an encoding of the real time data. By adjusting the number of such sessions dynamically, client-specific QoS constraints are met independently. The SomeCast paradigm can be thought of as a generalization of the AnyCast and ManyCast paradigms, which have been proposed in the literature to address issues of scalability of UniCast and MultiCast environments, respectively. The authors overview the SomeCast paradigm, describe an instance of a SomeCast protocol, and present simulation results that quantify the significant advantages gained from adopting such a protocol.