Low cost algorithms for message delivery in dynamic multicast groups

Heuristics for constructing low-cost multicast spanning trees in a dynamic environment are investigated. Two heuristic algorithms are developed that update the multicast tree incrementally as the membership changes and reduce the total bandwidth required for sending data and control messages. The broadcast tree based algorithm makes use of a tree structure in the network, and the other algorithm joins a new member to the node that is nearest to it and is already in the multicast tree. A simulation model is used to study the performance of the algorithms and to compare them with the best-known heuristic algorithm developed by D.W. Wall (1980) which computes the multicast tree structure for a given membership of the group. >