The failure of watchdog schemes in MANET security: a case of an intelligent black-hole

A wireless Mobile Ad-hoc Network (MANET) provides the possibility of communicating anytime anywhere in a temporary arrangement in the absent of a pre-existing network infrastructure. However, this presents new security challenges in comparison to the conventional wired and wireless networks, as it is more vulnerable to malicious attacks due to its unique features. Nodes' cooperation in MANET is a necessity for the routing protocol in use to achieve the desired routing purpose, to allow for efficient exchange of information in such temporal network. The implementation of transmission power-aware algorithms in the classical MANET routing protocols such as ad hoc on-demand distance vector (AODV), to preserve the nodes' limited battery power complicates the possibility of relying entirely on watchdog mechanisms to safeguard the network against black-hole attack. Furthermore, the watchdog's eavesdropping operation requires buffering of large amount of packets during the monitoring process. This paper proposes an algorithm which utilises cluster-heads and votes from neighbourhood nodes to detect and avoid malicious nodes. It addresses watchdog scheme's weakness in detecting black-hole attack in the presence of power-aware routing protocol, thereby increasing the overall network performance in terms of throughput and packet delivery ratio.