Research And Improvement Of Multicast Routing Protocolin Ad Hoc Networks

Mobile Ad Hoc Wireless Network (MANET) is a self-organizing, dynamic topology network formed by a collection of wireless mobile nodes without required intervention of any existing infrastructure or administrative support nodes. When it is compared with traditional networks based on fixed infrastructure, it is acentric and self-organize,the wireless hosts are designed to serve as routers and assist each other in delivering data packets if necessary. Due to the mobility of the nodes, the topology of the network may rapidly be changing, Therefore, mobile Ad Hoc networks are every important and useful, especially in mobile meeting, urgent service, personal networks and military wireless communication.Multicasting is the transmission of datagram to a group of hosts identified by a single source address and hence it is intended for group oriented computing. Traditional internet multicast routing Protocols can not meet the quickly-changing of the network topology, so designing the new multicast routing protocols which are suitable for Ad Hoc network is hotspot. In the existing multicast protocols, Tree-based multicast protocols don't perform well in MANET environment due to frequent tree reconstruction caused by nodes' mobility. And the extra overhead of redundant paths in Mesh based multicast protocols limits its scalability.Now, for solve large-scale Ad Hoc network multicast routing, cluster algorithm is the most effective solution. The thesis have explained the mechanism of the ODMRP relatively excellent performance in Ad Hoc network emphatically. And we proposed a new on-demand multicast routing protocol ODCMRP, which based on cluster by extending ODMRP. The cluster head is selected through four color algorithm as to build up the logical structure of the network, it can significantly less overlap.Finally, on platform of the OMNET++, simulated the different protocols including ODMRP and ODCMRP. The simulation result has shown that ODCMRP have more excellent performance than basic ODMRP on the aspects of packet overhead and forwarding efficiency when the size of multicast group grows up.