Caching of routes in ad hoc on-demand distance vector routing for mobile ad hoc networks

Ad hoc networks are characterized by multihop wireless connectivity, frequently changing network topology and the need for efficient dynamic routing protocols. Recent comparative studies between Ad hoc on demand routing protocols like Ad hoc On demand Distance Vector routing (AODV) and Dynamic Source Routing (DSR) (the two on demand routing protocols for Ad hoc networks) have shown that AODV performs better than DSR for high mobility cases but faces the problem of high routing and MAC load as compared to DSR. This is because DSR resort to aggressive use of caching of routes while AODV does not. In this paper, we have incorporated caching of routes in AODV with the aim to reduce the routing and MAC load of AODV without changing the basic structure of the protocol. A detailed simulation model with MAC and physical layer models is used to study the effect of caching of routes in AODV and to compare its performance with AODV without cache and DSR. We show that caching of routes in AODV can lead to significant reduction in routing and MAC load as well as in delay in delivering the packet as compared to AODV without much compromise in terms of packet delivery fraction.