Mitigating routing misbehavior in disruption tolerant networks

In disruption tolerant networks (DTNs), selfish or malicious nodes may drop received packets. Such routing misbehavior reduces the packet delivery ratio and wastes system resources such as power and bandwidth. Although techniques have been proposed to mitigate routing misbehavior in mobile ad hoc networks, they cannot be directly applied to DTNs because of the intermittent connectivity between nodes. To address the problem, we propose a distributed scheme to detect packet dropping in DTNs. In our scheme, a node is required to keep a few signed contact records of its previous contacts, based on which the next contacted node can detect if the node has dropped any packet. Since misbehaving nodes may misreport their contact records to avoid being detected, a small part of each contact record is disseminated to a certain number of witness nodes, which can collect appropriate contact records and detect the misbehaving nodes. We also propose a scheme to mitigate routing misbehavior by limiting the number of packets forwarded to the misbehaving nodes. Trace-driven simulations show that our solutions are efficient and can effectively mitigate routing misbehavior.