| Abstract: | ABSTRACT Security is an essential service for mobile network communications. Routing plays an important role in the security of mobile ad-hoc networks (MANETs). A wide variety of attacks targets the weakness of MANETs. By attacking the routing protocols, attackers can absorb network traffic, injecting themselves into the path between the source and destination. The black hole attack is one of the routing attacks where a malicious node advertise itself as having the shortest path to all nodes in the network by sending fake route reply. In this paper, a defense scheme for detecting black hole node is proposed. The detection is based on the timing information and destination sequence numbers maintained in the Neighborhood Route Monitoring Table. The table maintains the record of time of Reply. A black hole node will send a route reply message without checking the routing table as the legitimate node normally does. This reduced reply time is used to detect the black hole node. To improve the security further, the destination sequence number is checked with the threshold value, which is dynamically updated. The simulation results demonstrate that the protocol not only detects black hole attack but also improves the overall performance. |
