Cooperation Based Defense Mechanism against Selfish Nodes in DTNs

While Delay Tolerant Networks (DTNs) have exposed to offer guaranteeing additions to infrastructure based networks, they introduce new issues. As the nodes in the DTNs use store-carry forward mechanism for routing, they need energy, battery power, bandwidth, memory or CPU utilization. Due to lack of these resources the node drops the packets. In this paper, firstly, we discuss different issues and research works carried out for selfish nodes' detection. Defending these selfish nodes accurately becomes vital in DTNs. In this paper, we present Cooperation Based Defense Mechanism (CBDM) against selfish nodes in DTNs. Furthermore, we study basic operations and security issues of Probabilistic Routing Protocol based on History Encounters and Transitivity (PRoPHET). This paper address a static mandatory cooperation scheme in which the nodes are forced to behave well. Moreover, a mechanism is used to calculate cooperation of selfishness of nodes by checking the number of sent messages and number of received messages. A bait detection scheme is used to confirm malicious behavior of suspicious nodes. Simulation results show that the proposed approach reduces the number of selfish nodes along with the decrease in the number of dropped packets and overhead ratio.