One of the most critical task for group communications lies in the establishment of multicast
trees on the network. Two famous multicast trees are the shortest path-based trees and the
Steiner-based trees. The former is suitable for those applications (such as video
conferences) which wish to have a low propagation delay between the source (chairman
site) to each of the receivers (member sites). The latter is well-suited for those (such as VoD
services) which tend to consume as small as possible network resources (bandwidth). So far …