ODVR: A Unifying Approach to On-Demand and Proactive Loop-Free Routing in Ad-Hoc Networks

We introduce Ordered Distance Vector Routing (ODVR), which is the first approach that enables on-demand and proactive loop-free routing on a per-destination basis. ODVR establishes a strict total ordering of nodes with respect to any given destination using the distances to that destination and reference distances that nodes responding to route requests must have in order to be allowed to send responses. Destinations send gratuitous route replies to enact proactive routing. In contrast to all prior routing protocols, ODVR does not require source or destination sequence numbers, sequence numbers for messages, path information, source routing, or requiring a router to wait for replies from all its neighbors before making changes to its routing table. It is shown that loop-free on-demand routing cannot be attained simply by using destination sequence numbers and the type of signaling used in AODV (Ad-hoc On-Demand Distance Vector) if messages can be lost and nodes may lose routing state for any reason. It is also shown that ODVR provides loop-free routes at every instant. Simulation experiments using ns3 show that ODVR is more efficient than AODV and OLSR.