A Cooperative Watchdog System to Detect Misbehavior Nodes in Vehicular Delay-Tolerant Networks

In vehicular delay-tolerant networks (VDTNs), an end-to-end relay path between bundle source and destination nodes may not be available. To accomplish such goal, VDTNs rely on nodes cooperation. Thus, in order to maintain network efficiency, it is very important to ensure that all network nodes follow the protocol. This is not an easy task since nodes may diverge from the protocol due to a selfish behavior or to maintain their data or resources integrity. This paper proposes a cooperative watchdog system to detect and act against misbehavior nodes in order to reduce their impact in the overall network performance. Its operation relies on a cooperative exchange of nodes reputation along the network. By detecting selfish or misbehaving nodes, it is possible to improve the overall network performance. Conducting simulation experiments considering the VDTNSim tool and the Spray-and-Wait routing protocol shows that the cooperative watchdog proposed for VDTNs is not only effective in detecting misbehaving nodes but also contributes to improve the overall network performance by increasing the bundle delivery probability and decreasing the amount of resources waste.