AN IMPROVED ACKNOWLEDGMENT SCHEME FOR DETECTING MISBEHAVING NODES IN MANETS

In Mobile Ad-hoc NETwork (MANET), mobile devices communicate via wireless links without the aid of any fixed infrastructure. The need of corporation for routing and data forwarding, lack of central monitoring, wireless medium and energy constrained battery operated nodes make the MANETs susceptible to security threats. A Selfish node may refuse to forward the packets of other nodes to save its own resources or a malicious node may drop the packets to disrupt the network function. Such selfish or malicious nodes are named as misbehaving nodes. In this paper, we propose an acknowledgment based scheme I-ACK (Improved ACKnowledgment), to detect packet dropping attack by misbehaving nodes and prevent these nodes to be chosen for path establishment. It is improved version of existing scheme AACK. We simulate this scheme using NS2 and compare the results with TWOACK and AACK schemes. I-ACK gives better Packet Delivery Ratio and lesser Routing overhead as compared to above two schemes. It shows visibly improved performance for the longer routes