The selective intermediate nodes scheme for ad hoc on-demand routing protocols

The on-demand routing schemes in mobile ad hoc networks are appealing because of the lower routing overhead, compared with traditional proactive schemes. The on-demand routing protocols introduce routing overhead only in the presence of data packets that need routes. However, the control overhead of on-demand routing schemes increases with node geographic density and traffic pattern density. In fact, this is an undesirable feature for the scalable routing protocols whose control overhead should be under control to keep up with increasing offered load. As a solution for such a drawback of current reactive routing schemes, we propose the selective intermediate nodes mechanism. In this protocol, each node adaptively propagates routing information based on the local load level and cluster status. The local load level (local load status), based on channel utilization and queue size, reflects the load of the node in question and of all of its neighbors; the cluster status denotes the role of a node in a cluster (i.e., a cluster head, gateway or ordinary node). We demonstrate the effectiveness of our enhancement by applying it to ad hoc on-demand distance vector routing (AODV) and dynamic source routing (DSR). Simulation results show that the proposed idea significantly reduces the control overhead and improves the overall performance and scalability of the routing protocols.