A Distributed Algorithm for Finding a Tree Trunk and its Application for Multicast in Mobile Ad Hoc Networks

Overlay multicast protocol constructs a virtual mesh spanning all member nodes of a multicast group and employs standard unicast routing to fulfill multicast functionality on application layer. The advantages of this approach are simplicity and flexibility. However, efficiency and stability are the issues that must be addressed as the size of the multicast group grows in the mobile ad hoc networks (MANETs). In this paper, we propose tree trunk for overlay multicast to solve these problems in MANETs. A tree trunk is a path that minimizes the sum of the distances of all vertices to the path plus the length of the path. We give an efficient distributed algorithm for finding a tree trunk in a tree network. We also perform some empirical analysis based on the tree trunk and compare the results with those using spanning tree.