Quality of Service Evaluations of On Demand Mobile Ad-Hoc Routing Protocols

A mobile ad hoc network (MANET) is a set of wireless mobile nodes that can communicate with each other without using any fixed infrastructure. It is also necessary for MANET devices to communicate in a seamless manner. There are multiple routing protocols that have been developed for MANETs. There is a need to support real time and multimedia applications in MANETs as they gain popularity. MANETs require an efficient routing protocol and quality of service (QoS) mechanism in order to support multimedia applications such as voice and video. Such applications have strict quality of service requirements such as bandwidth, delay, and jitter. Design and development of routing algorithms with QoS support is experiencing increased research interest. This paper evaluates the QoS performance of MANETs by comparing the results of using AODV and DSR routing protocols. Using the OPNET Modeler, we have conducted an extensive set of performance experiments for these protocols with a wide variety of settings. The results show that DSR would be the best protocol to use with voice based traffic as long as mobility is kept to a minimum. As network size and mobility increases, AODV is the better choice due to the on-demand nature allowing for much higher mobility because of the non-caching nature of the routes. However, when resource intensive applications such as voice and video are introduced, the on-demand nature of AODV severely hampers network performance. Even with QoS, AODVs route discovery cannot keep up with the requirements of these applications and this is where DSR´s route caching truly shines.