Trust Appraisal Based Neighbour Defense Secure Routing to Mitigate Various Attacks in Most Vulnerable Wireless Ad hoc Network

The Mobile Ad hoc network is the most growing field as it is dynamic in nature and requires no central authority to manage it. In this paper we have worked on routing layer of MANET. We have worked upon AODV (Ad hoc on-demand distance vector) routing protocol. In this paper we have developed a very vulnerable network and a number of attackers and also modified AODV with our trust-based approach. To the best of our knowledge no one has implemented strong attackers and prevented them. In our approach each node monitors its neighbours’ activities and develops a trust table which in turn is very difficult to maintain when there is no cooperation between nodes. Based on the trust table it decides whether to eliminate the attacker. We have also optimized HELLO packet of AODV in such a way that it propagates information about malicious node among other available nodes and isolates the attacker from the entire network. At the end we present the results which clearly show that proposed protocols perform better than AODV in vulnerable situation. To evaluate the performance, we have carried out an extensive simulation study of AODV and modified AODV using NS2.35 with and without attacker showing significant improvement in Packet Delivery Fraction (PDF), Packet Drop Ratio (PDR), Average Throughput (AT), Normalized Routing Load (NRL) and E2E (Average End-2-End delay).