Building dynamic multicast trees in mobile networks

As group applications become more prevalent, efficient network utilization becomes a major concern. Multicast transmission may use network bandwidth more efficiently than multiple point-to-point connections. Many algorithms have been proposed for generating "good" multicast trees, however, these algorithms have significant limitations for networks containing mobile hosts. Existing algorithms either do not support changes to the multicast group while building the tree or impose unrealistic restrictions such as prohibiting overlapping modifications or forcing regeneration of the tree after each change. Clearly, to extend the range of applications that depend on multicast communication to mobile hosts, multicast tree algorithms must provide a flexible means for participants to join and leave the multicast group. We propose an efficient distributed algorithm that supports dynamic changes to the multicast group during tree building and allows overlapping join/leave operations. In this paper, we present the algorithm and initial simulation results.