Detection and avoidance of malicious node in MANET

Mobile ad-hoc network (MANET) is an autonomous system of mobile nodes connected by wireless links; each node operates as an end system and a router for all other nodes in the network. Nodes in mobile ad-hoc network are free to move and organize themselves in an arbitrary fashion. The path between each pair of the users may have multiple links and the radio between them can be heterogeneous. Use of wireless links renders an Ad hoc network susceptible to link attacks ranging from passive eavesdropping to active impersonation, message replay and message distortion. The routing protocols for Ad hoc networks cope well with dynamically changing topology but are not designed to accommodate defense against malicious attackers. The same is true for AODV routing. In this paper I have implemented the malicious node which periodically drops packets and study its effect in wireless LAN and AODV routing. I have also implemented the improved AODV which detects and avoid such nodes while route is established in AODV. The simulation results show that the route discovery time and throughput is improved in modified AODV then normal.