Efficient Use of Route Requests for Loop-Free On-demand Routing in Ad Hoc Networks

We present a new loop-free on-demand routing protocol for ad-hoc networks, the Labeled Successor Routing (LSR) protocol, which identifies loop-free successors to a destination using route-request labels (RRL). Each route request (RREQ) used during the on-demand destination search process is identified uniquely by a sequence number associated with the issuing source address. Route replies (RREP), which traverse loop-free paths created by RREQs, carry the associated RRL that is stored by nodes along the created successor path to the destination. Without requiring an additional mechanism for loop-freedom (e.g., per destination-sequence numbers or source-routing) LSR allows neighbors of a source to reply to RREQs, avoiding the destination being the only node capable of replying. Simulations results for scenarios consisting of networks of 50 and 100 mobile nodes show that LSR performs comparably or better than the Dynamic Source Routing (DSR) protocol, AODV, and the Optimized Link State Routing (OLSR) protocol.