Abstract—An ad hoc network is a collection of wireless mobile nodes that forms a temporary network without any centralized administration. While early research effort assumed a friendly and cooperative environment and focused on problems such as wireless channel access and multihop routing, security has become a primary concern in order to provide protected communication between nodes in a potentially hostile environment. Research in wireless indicates that the wireless MANET presents a larger security problem than conventional wired and wireless networks. This paper analyses the black hole and cooperative black hole attack which is one of the new and possible attack in adhoc networks. A black hole is a type of attack that can be easily employed against routing in mobile adhoc networks. In this attack a malicious node advertises itself as having the shortest path to the node whose packets it wants to intercept. To reduce the probability it is proposed to wait and check the replies from all the neighboring nodes to find a safe route. If these malicious nodes work together as a group then the damage will be very serious. This type of attack is called cooperative black hole attack. Our solution discovers the secure route between source and destination by identifying and isolating black hole nodes. In this paper, via simulation, we evaluate the proposed solution and compare it with standard DSR protocol in terms of throughput, Packet delivery ratio and latency. We have conducted extensive experiments using the network simulator-2 to validate our research.

Index terms—Trust based routing, secured routing, blackhole attack, Cooperative blackhole attack, adhoc networks, DSR protocol

Cite: N. Bhalaji and A. Shanmugam, "Defense Strategy Using Trust Based Model to Mitigate Active Attacks in DSR Based MANET," Journal of Advances in Information Technology, Vol. 2, No. 2, pp. 92-98, May, 2011.doi:10.4304/jait.2.2.92-98