Detection And Removal Of Node Isolation Attack In OLSR Protocol Using Imaginary Nodes With Neighbour Response In MANET

MANET is an open wireless, infrastructure less and topology less network environment in which nodes are free to move anywhere in the network. Various types of protocols are used for communication. The proactive protocol OLSR in which one MPR node is selected for transmission of messages. As the MANET is open network any malicious node can easily enter into the network and affect the network performance. Which is mainly depends on the components which participates into the communication. There are different kind of Denial of Service (DoS) attacks such as Node isolation attack where attacker node isolates the node from the rest of the network using some imaginary (fictitious) nodes. The proposed work implements some contradiction rules to find the attack using same technique used by the attacker. we implement the acknowledgement scheme to check whether node is still connected to the network or alive. According to the TTL value we will check it. If MPR node found guilty, new MPR will be selected from the set. We considers neighbors' response about the node and according to time to ACK we chooses another MPR node.