Way Directing Node Routing Protocol for Mobile Ad Hoc Networks

Abstract

A Mobile Ad hoc Network (MANET) is a collection of wireless nodes, forming a temporary network without using any fixed architecture. Communications among the nodes of a MANET are accomplished by forwarding data packets for each other, on a hop by hop basis. The research in this area is commonly simulation based as not many ad hoc networks are currently deployed. Based on routing topology, routing protocols in MANETS are categorized as flat routing and hierarchical routing. In flat routing protocols like DSR and AODV, every node has assigned uniform functionalities. But their performance degrades as the network size grows. Hierarchical routing protocols like CGSR and HSR maintain hierarchy on entire network. But overhead may be high to maintain hierarchy in the mobile network environment. In this paper we propose an On Demand Hierarchical Routing protocol, in which certain number of intermediate nodes present on the route-path are selected as way-nodes and the entire route-path is partitioned into segments by these way-nodes. We call this protocol as Way Directing Node Routing (WDNR), in which the source and destination nodes run a high level inter-segment routing approach. Within each segment it runs a low-level intra-segment routing protocol. The main advantage of this protocol is, when a link on a route-path fails due to node mobility, instead of discarding entire route and rediscovering the fresh route between source and destination, the broken link can be repaired locally. Our model is light weight compared to basic hierarchical routing, as the selection of way-nodes is made only for active routes, on an on-demand basis. Our WDNR protocol uses AODV as intra-segment routing protocol and DSR as inter-segment routing protocol. It mainly solves the scalability problem of flat routing and overhead problem of hierarchical routing. WDNR protocol also exhibits the functionality required to scale large networks and reduce the overhead in hierarchy maintenance. Simulations are carried out in GloMoSim. The simulation results show that WDNR scales better for larger networks with higher than 800 nodes, incurring about 50 to 70 percent less overhead than AODV protocol, while other performance metrics are comparable to basic DSR and AODV.