CONTACT DISSEMINATION BASED COLLABORATIVE WATCHDOG APPROACH TO IMPROVE SELFISH NODE DETECTION IN MANETS

Mobile ad hoc networks are composed of mobile nodes connected by wireless links without any pre-existing infrastructure. MANET nodes rely on network cooperation schemes to properly work, forwarding traffic unrelated to its own use. However, in the real world, most nodes may have a selfish behaviour, being unwilling to forward packets for others in order to save resources. The selfish nodes are not malicious but are reluctant to spend their resources such as CPU time, memory and battery power for others. Therefore, detecting these nodes is essential for network performance. Watchdogs are used to detect selfish nodes in computer networks. A way to reduce the detection time and to improve the accuracy of watchdogs is the collaborative approach. This paper proposes a collaborative watchdog based on contact dissemination of the detected selfish nodes. Then, we introduce an analytical model to evaluate the detection time and the cost of this collaborative approach. Numerical results show that our collaborative watchdog can dramatically reduce the overall detection time with a reduced overhead.