A novel scheme for supporting integrated unicast and multicast traffic in ad hoc wireless networks

摘要

Current multicast routing protocols for mobile ad hoc networks can be classified into two categories, tree-based protocols and mesh-based protocols. Mesh-based protocols have high packet delivery ratios compared to tree-based protocols, but incur more control overhead. Though the control overhead involved in tree-based protocols is low, the performance in terms of packet delivery ratio of such protocols, decreases with increasing mobility. This is due the lack of proper tree maintenance mechanisms. We propose an efficient multicast routing protocol called preferred link-based multicast protocol that uses a preferred link approach for forwarding JoinQuery packets. This approach reduces control overhead during the forwarding of JoinQuery packets. In this approach only a subset of neighbors of a node, that are termed as preferred nodes, are made eligible for further forwarding of JoinQuery packets. These preferred nodes are selected using our preferred link-based algorithm. We conducted extensive simulation experiments to evaluate the proposed protocol and have compared our protocol with some of the existing protocols. The simulation results show that our protocol performs better than the other multicast protocols in terms of packet delivery ratio and control overhead.Further, we have extended our multicast protocol to support unicast and multicast traffic simultaneously. This unified approach for routing is analyzed in order to study the impact of unicast traffic on multicast traffic, and vice versa. Performance evaluation of the unified approach, that we term as preferred link-based unified routing, was carried out through extensive simulation experiments. (C) 2004 Published by Elsevier Inc.