Congestion avoidance routing protocol for QoS-aware MANETs

With the increase of multimedia traffic over the past few years and traffic differentiation introduced by IEEE 802.11e, nodes with delay-sensitive multimedia traffic tend to be busy for long periods, thus exacerbating the congestion problem in Mobile Ad Hoc Networks (MANETs). Although most of the existing routing protocols are based on the shortest path algorithm, some other metrics like load and delay have also been considered in some other research. In this paper, we first expose that the performance of MANETs routing protocols is highly dependent on the type of traffic generated or routed by intermediate nodes. This paper proposes a Type of Service Aware routing protocol (TSA), an enhancement to AODV, which uses both the ToS and traditional hop count as route selection metrics. TSA avoids congestion by distributing the load over a potentially greater area and therefore improving spatial reuse. Our simulation study reveals that TSA considerably improves the throughput and packet delay of both low and high priority traffic under different network operational conditions.