Manet Reactive Routing Protocols Node Mobility Variation Effect in Analysing the Impact of Black Hole Attack

MANETs are exposed to numerous security threats due to their characteristic features, which include absence of centralised control unit, open communication media, infrastructure-less and dynamic topology. One of commonest attack is known as black hole attack, which mostly targets the MANETs reactive routing protocols, such as AODV and DSR. Simulation scenarios of AODV and DSR based MANET were conducted using Network Simulator 2 (NS-2) and NS-3, while introducing the black hole attack in each of the scenarios, to analyse the protocols’ performances. The different scenarios are generated by changing the mobility (locations) of the nodes. The performance metrics that are used to do the analysis are throughput, end-to-end delay and packet delivery ratio. The simulation results showed that the performance of both AODV and DSR degrades in the presence of black hole attack. Throughput and packet delivery ratio decrease when the network is attacked by black hole, because the malicious node absorbs or discards some of the packets. End-to-end delay is also reduced in the presence of a black hole attack because a malicious node pretends to have a valid route to a destination without checking the routing table, and therefore shortens the route discovery process. The results also showed that throughput decreases slightly when mobility of the nodes is increased in the network. The increase in the speed of the nodes decreases both packet delivery ratio and end-to-end delay. The closer the black hole node was to the source node requesting the transmission, the worse the impact. A focused analysis on AODV indicates that, even with the introduction of relatively few black hole nodes to the network, there still exist a potential to bring significant disruptions to communication.