A New Protocol for Detecting Black Hole Nodes in Ad Hoc Networks

An ad hoc network is a collection of infrastructure less nodes, cooperating dynamically to form a temporary network which meets certain immediate needs. The lack of in frastructure implies that the nodes are connected peer-to-peer. Therefore, each node acts as a router beside its main role as a hos t. With the increased number of mobile devices, the application s of ad hoc network increased dramatically to capture different domains such as: academic communication, and mobile conferencing beside its traditional domains such as: military communication , and emergency communication. Security issues become more challenging in ad hoc n etwork due to its dynamic nature which allows any node to freely join as well as leave the network without having a physical address or getting permission. Ad hoc networks are vulnerable to diffe rent kinds of attacks such as: denial of services, impersonation, and eavesdropping. This paper discusses one of the security problems i n ad hoc networks called the black hole problem. It occurs w hen a malicious node referred as black hole joins the network. The black hole conducts its malicious behavior during the process of route discovery. For any received RREQ, the black hole cl aims having a route and propagates a faked RREP. The source node responds to these faked RREPs and sends its data through the re ceived routes. Once the data is received by the black hole, it is dropped instead of being sent to the desired destination. The proposed protocol is built on top of the origin al AODV. It extends the AODV to include the following functionalities: source node waits for a reliable route; each node has a ta ble in which it adds the addresses of the reliable nodes; RREP is o verloaded with an extra field to indicate the reliability of the r eplying node. The simulation of the proposed protocol shows significa nt improvement in the terms of: packet delivery ratio, number of d ropped packets, and end-to-end delay. The overhead still needs more researches .