Technique for detection of cooperative black hole attack in MANET

Mobile Ad Hoc Network (MANET) is a collection of communication devices or nodes that wish to communicate without any fixed infrastructure and predetermined organization of available links. Security is a major challenge for these networks due to their features of open medium, dynamically changing topologies. The black hole attack is a well known security threat in mobile ad hoc networks. However, it spuriously replies for any route request without having any active route to the specified destination. Sometimes the Black Hole Nodes cooperate with each other with the aim of dropping packets these are known as Cooperative Black Hole attack. This research work suggests the modification of Ad Hoc on Demand Distance Vector Routing Protocol. we are going to use a mechanism for detecting as well as defending against a cooperative black hole attack. This work suggest two new concepts, first one is Maintenance of Routing Information Table and second is Reliability checking of a node. This system also decreases the end to end delay and Routing overhead.