Mobile Intelligence

16.4 ROBUST SOURCE ROUTING

In this section, we present a secure on-demand, multipath source routing protocol, called robust source routing (RSR). In addition to providing data origin authentication services and integrity checks, RSR is able to mitigate against intelligent malicious agents that selectively drop or modify packets they agreed to forward. Simulation studies confirm that RSR is capable of maintaining high delivery ratio even when a majority of the MANET nodes are malicious.

RSR has two phases: route discovery and route utilization and maintenance. We give an overview of each phase below.

16.4.1 Route Discovery

In the route discovery phase, a source node S broadcasts a route request indicating that it needs to find a path from S to a destination node D. In the route request, S stipulates that the path it seeks must not contain any node that is listed in its tabu list, or any link that appears in its exclusion links list. We provide a rationale for the tabu list and exclusion links list in Section 16.4.4. Additionally, the path must not contain any node that is found in the tabu list of an element in the path. Each node through which the route request traverses is required to append its identifier and its tabu list to the appropriate field of the route request, and signs the packet. Therefore, the information regarding the identity of the nodes that should be excluded from the path is easily ascertained. When the route request packets arrive at the destination node