P-AODV: A Priority Based Route Maintenance Process in Mobile Ad Hoc Networks

Abstract

We present a route maintenance mechanism, P-AODV, which repairs a route by selecting a neighbor on the basis of the traffic being handled by it. A new parameter, priority, is introduced to segregate the nodes into high priority and low priority categories. The availability of a high priority neighbor is required for the success of P-AODV. A highly dense network--our focus--increases the probability of such neighbors in the vicinity of upstream nodes. The priorities are advertised through Hello Packets and stored in Neighbor Tables. Alternate paths are made available at neighbor nodes by overhearing the traffic. In dense networks, avoiding reroute discoveries by selecting neighbors averts the overhead caused by control packets, inherent congestion and delay. Further, we have introduced a Controlled Re-Route Discovery in P-AODV to reduce the control packets transmission. P-AODV substantially improves the overall performance of the network. In this paper we have implemented our algorithms in AODV code of network simulator, ns 2.34, and the results were compared with the existing route maintenance methods of AODV, and RLLR. Chain topologies, running constant bit rate, are created with some neighbors either common to the chains or standalones. The simulation results show significant improvement in routing overhead reduction, packet delivery ratio, and considerable improvement in throughput and end-to-end delay (reduction), comparing P-AODV and AODV.