Dynamic nix-vector routing for mobile ad hoc networks

We present a new protocol for multi-hop routing in mobile ad hoc networks called dynamic nix-vector routing (DNVR). Our scheme is based on the nix-vector concept for efficient routing originally designed for wired networks. DNVR acquires a loop-free route and maintains it on a need basis as do other on-demand protocols. However, DNVR has several new features as compared to other existing reactive routing protocols which lead to more stable routes and better scalability. DNVR effectively validates the stored routes as well as efficiently senses the up-to-date network topology during a route discovery phase by sending a unicast probe packet. To accommodate networks with a high degree of mobility, the routing states are invalidated in a timely manner. DNVR adopts a conservative route discovery strategy by suppressing route requests in some cases, and thus only a few routes are maintained per destination. Moreover, it attains bandwidth efficiency by using a neighbor index and medium access control (MAC) addresses for routing purposes, which obviates the need for address resolution. We show via simulation that DNVR scales well to a large network with varying traffic load under diverse mobility scenarios. We compare DNVR to the well known dynamic source routing (DSR) protocol, which is believed to be one of the most efficient on-demand routing protocols. Simulation results reveal that DNVR is as efficient as DSR while at the same time providing higher packet delivery ratios (up to 46 % higher) and smaller delays (up to 23 % smaller) than DSR in most cases.