A workload-based adaptive load-balancing technique for mobile ad hoc networks

Abstract

A novel load-balancing technique for ad hoc on-demand routing protocols is presented. Currently, ad hoc routing protocols lack load-balancing capabilities, and thus, they often fail to provide good performance especially in the presence of a large volume of traffic. We present a simple but very effective method to achieve load balance and congestion alleviation. The new scheme is motivated by the observation that ad hoc on-demand routing protocols flood route request (RREQ) messages to acquire routes, and only nodes that respond to those messages have a potential to serve as intermediate forwarding nodes. If a node ignores RREQ messages within a specific period, it can completely be excluded from the additional communications that might have occurred for that period otherwise. Thus, a node can decide not to serve a traffic flow by dropping the RREQ for that flow. In the new scheme, RREQ messages are forwarded selectively according to the load status of each node so that overloaded nodes can be excluded from the requested paths. Each node begins to allow additional traffic flows again whenever its overloaded status is dissolved. The new scheme utilizes interface queue occupancy and workload to control RREQ messages adaptively. The enhanced versions of protocols with this scheme are compared to the base protocols. Simulation results reveal that the new scheme greatly reduces packet latency as well as routing overhead without adversely affecting the network throughput, and it successfully balances the network load among nodes.