A Survey on Efficient Detection of Selfish Nodes in Manet Using a Collaborative Watchdog

Misbehavior of Nodes is basically due to selfish or faulty nodes or malicious reasons can degrade the performance of Mobile ad-hoc networks (MANETs). To handle with misbehaviour in such self-organised networks, nodes need to adapt their strategy to changing levels of cooperation. This cooperation is a cost-intensive activity and some nodes can refuse to cooperate, leading to a sel�sh node behaviour. Hence, the overall network performance could be affected seriously. The well-known mechanism to detect sel�sh nodes are watchdogs. However, the detection process handled by watchdogs can fail, reporting false positives and false negatives which leads to wrong operations. Besides, depending on local watchdogs alone can lead to bad performance when detecting sel�sh nodes, in term of precision and speed.. Thus, we propose CoCoWa as a collaborative contact-based watchdog to reduce the time and improve the effectiveness of detecting selfish nodes, reducing the harmful effect of false positives, false negatives and malicious nodes. CoCoWa is based on the diffusion of the known positive and negative detections. When a contact occurs between two collaborative nodes, the diffusion module transmits and processes the positive (and negative) detections. Analytical and experimental results show that CoCoWa can reduce the overall detection time with respect to the original detection time when no collaboration scheme is used, with a reduced overhead (message cost).