E-ODMRP: enhanced ODMRP with motion adaptive refresh

On demand multicast routing protocol (ODMRP) is a multicast routing protocol for mobile ad hoc networks. Its efficiency, simplicity, and robustness to mobility renders it one of the most widely used MANET multicast protocols. At the heart of the ODMRP\´s robustness is the periodic route refreshing. ODMRP rebuilds the data forwarding "mesh" on a fixed short interval. The route refresh interval has critical impact on protocol overhead and thus efficiency. If it is too high, the network undergoes too much routing overhead wasting valuable resources. If it is too low, ODMRP cannot keep up with network dynamics. In this paper, we present an enhancement of ODMRP with refresh rate dynamically adapted to the environment. An additional enhancement is "unified" local recovery and receiver joining. On joining or upon detection of a broken route, a node performs an expanding ring search to graft to the forwarding mesh. Simulation results show that the enhanced ODMRP (E-ODMRP) reduces overhead by up to 90% yet keeping similar packet delivery ratio compared to the original ODMRP.