"Direction" Forward Routing for Highly Mobile Ad Hoc Networks

Popular ad hoc routing protocols such as DSDV and AODV use “predecessor” based forwarding, namely, the packet is forwarded to the predecessor that advertised the shortest path to destination during the last update. However, if the predecessor moves, the routing table entry becomes invalid and predecessor based forwarding fails! To overcome the stale forward table problem, in this paper we propose a novel packet forwarding scheme called “direction” forwarding (DFR). When an update is received, a node records the “geographical direction” to where the update came from. When predecessor forwarding fails, the packet is forwarded to the “most promising” neighbor in the recorded direction. If the network is sufficiently dense and the routing algorithm includes periodic refresh from destination, direction forwarding will recover from most “predecessor” failures due to motion. We evaluate DFR in a LANMAR routing scenario where the direction to each Landmark is periodically refreshed. Through simulation we show that DFR considerately enhances LANMAR performance in large, mobile network scenarios.