Performance study of quality of service routing protocols in MANETs

Abstract

Recent growth and widespread attention given to mobile communications has led to rapid proliferation in research and development involving mobile wireless networks. The need for easy deployment and self-configured networks makes mobile ad-hoc networks (MANETs) an attractive choice for various applications. However, due to its dynamic nature and imprecise network state information, there are many challenges which need to be addressed including Quality of Service (QoS) routing. Numerous approaches have been proposed including QoS-AODV. It is proposed to enhance one of the existing routing protocols for MANETs namely AODV (Ad-Hoc On-Demand Distance Vector). QoS-AODV adds necessary new fields to cater QoS provisioning requirements. Due to its ease of integration and simplicity, this protocol has been selected for evaluation study. The existing QoS-AODV implementation utilizes minimum bandwidth extension in assuring QoS guarantee. Apart from bandwidth, delay is also a critical parameter with regards to multimedia application which has been garnering rising attention lately. The first aim of this thesis is to conduct evaluation study on two QoS-AODV approaches. One approach makes use of HELLO messages and another makes use of link-layer feedback. Meanwhile, our highlighted contribution includes the extension of maximum delay field in addition to the existing minimum bandwidth field as part of our enhancement proposal. The combination of bandwidth and delay metrics for AODV is vital for maximizing bandwidth and reducing end-to-end delay. In order to identify the pros and cons of both methods as well as to test our proposed mechanism, NS-2 Simulator is used to conduct the simulation study. Average Latency, Packet Delivery Ratio (PDR) and Normalized Overhead are the selected evaluation metrics. Our experiments study the effect of number of mobile nodes, mobility and traffic load on different enhancements of AODV protocol. Through the simulation study performed, the shortcomings and strengths of the simulated approaches have been identified thus directing to suggestions for future works.