ODMRP-LR: ODMRP with Link Failure Detection and Local Recovery Mechanism

On Demand Multicast Routing Protocol (ODMRP) was designed formerly for multicast routing in ad hoc networks. Despite good delivery ratio in several scenarios, ODMRP relies on a periodic refresh mechanism for sending the JOIN QUERY message to maintain mesh robustness. Choosing the appropriate value for refresh interval of this message is of great concern. In addition when mobility speed is high, link failures occur more causing delivery ratio to decrease. In this paper we address the problems of detecting link breakages and local recovery procedure in ODMRP. We introduce a new join message for nodes intending to join the multicast group and nodes detecting link breakage. Through this message, receivers have no delay and no loss in receiving data packets. Furthermore we propose the concept of minimum number of neighbors in ODMRP mesh for detecting links failure based on data packets with no control overhead. Simulation results show that with these improvements packet delivery ratio increases while end-to-end delay remains the same as ODMRP.