Evaluation of parameterised route repair in AODV

One of the key challenges for routing protocols in wireless multi-hop networks is to deal with link failures, and to repair the routes in these situations. In the Ad-hoc On Demand Distance Vector (AODV) protocol, routes can either be repaired by re-establishing a new route from scratch starting from the source node (Source Repair), or they can be locally repaired by the node that detects the link break along the end-to-end path (Local Repair). In some situations Source Repair will lead to better performance, in other situations Local Repair will be the more appropriate choice. In this work, we explore a flexible, parameterised approach in deciding on which of these two route repair strategies to use in the event of a link break. We define a Local Repair Threshold parameter that determines how far along the end-to-end path that a link break needs to occur in order to initiate Local Repair, as opposed to Source Repair. Our simulation results show that the optimal choice of the Local Repair Threshold, in terms of Packet Delivery Ratio, depends on the network load. We show that a flexible, parameterised and adaptive approach to choosing the Local Repair Threshold, can improve the Packet Delivery Ratio by up to 37% (in absolute terms), compared to the approach employed by standard AODV. We also show a significant potential improvement of up to 18% over the route repair strategy employed by the Dynamic On demand MANET (DYMO) routing protocol, which is based on AODV.