Multipath Routing Protocol with Backtracking for Mobile Ad Hoc Networks

A mobile ad hoc network (MANET) is characterized by multi-hop wireless links in the absence of cellular infrastructure and frequent host mobility. In this paper, a new on-demand routing protocol is proposed, named on-demand routing protocol with backtracking (ORB), for multi-hop mobile ad hoc networks. Suppose a source host wants to deliver a message to a destination in a MANET. First, the source host issues a request to search the destination. When a node receives the request packet, it gets a hop count value which can point the way to the source. This node broadcasts the request packet to its neighbors. When a destination receives this request, it issues a reply back to the source. We proposed a scoped flooding approach which is applied to reply information to the source. This approach will find out multi-path from a source to a destination. Every node in the MANET maintains some information for this source-destination pair in its own route table. Each node in the forwarding route uses this information to select a group of nodes, named checkpoint nodes, which may have multi-path maintained to that destination. The checkpoint node characteristic is such that a route can be recovered instantly without the need for extra control packets. When a delivering node is aware that the forwarding route is broken, it transmits an error packet back to the source along the return path. When a checkpoint receives the error packet that is backtracked to the source, it has backup paths to recover the broken route. This new route can be used immediately. The main advantage of our ORB is to reduce the flooding search time and cost when a route has been broken. We show that the proposed scheme outperforms the on-demand routing protocol existing in mobile ad hoc networks.