An efficient fault-tolerant multicast approach for wireless mobile systems

This paper presents an efficient approach to providing mobile multicast with the fault-tolerant capability. In multicast communication, packets can be concurrently sent from a source node to all the members by means of a multicast delivery tree. If a failure occurs in one node (link) of the multicast tree, the faulty tree will be partitioned into several disconnected subtrees. The multicast service for some members will be disrupted. The main goal of this paper is to make members immune from failure affection. The proposed approach contains two schemes. The first scheme uses the redundant resources of a mobile network to reconnect the disconnected subtrees. Unlike the traditional approaches, the first scheme does not generate loops. In addition, it can control the maximum delivery delay of the new reconnected multicast tree. The second scheme is issued when the first scheme cannot reconnect all the subtrees based on the network topology support. It extracts the failure-free part of the faulty multicast tree to form a safe multicast subtree. Then, all the members are virtually moved to the delivery range of the safe multicast subtree to continuously receive multicast packets. Finally, the fault-tolerant capability of the proposed approach and its overhead are examined and compared with previous approaches by simulation.