Mitigating the Effect of Blackhole Attack on MANETs using AODV Protocol Under Transmission Control Protocol
Ola Malawi and Mohammad S. Obaidat
Mobile Ad-hoc Networks (MANETs) are defined as temporal and infrastructure-less networks, which are formed without any established infrastructure or fixed centralized point. Nodes dynamically collaborate to establish routs themselves. The self-configuring nature allows many threats to occur and corrupt network’s functionality. Blackhole attack is a type of attacks in which a malicious node participates in MANET and claims that it has the best route towards the requested destination. Hence, nodes forward packets to the malicious node, which immediately drops them. This attack can cause a huge damage in network functionality. In the state of art, TCP has been very slightly, if not never, investigated over AODV when studying blackhole attack. In this paper, the impact of blackhole attack in AODV protocol is examined and discussed under TCP protocol. Then, a new approach is proposed to mitigate the effect of blackhole attack on MANETs using random route selection, and with exploitation of TCP basics to detect and reject malicious nodes. A new performance evaluation metric, relative delivery ratio RDR, is proposed. The performance of the network is compared in the standard network environment, completely blackhole attacked environment, and an environment under blackhole attack using the proposed approach. The proposed scheme is simulated using Network Simulator 2 (NS-2), and performance is evaluated under different movement scenarios and different numbers of malicious nodes in the network. It was found that the proposed scheme improves the performance of MANET under blackhole attack and could recover up to 50% of normal network behavior.
Keywords: Mobile ad hoc network, malicious node, route reply, reply caching, encryption, monitoring, NS-2, simulation.