Rajesaheb Kadam, Manoj Bangare
Abstract: Delay-Tolerant networks (DTNs) provide solution to applications where end to end connectivity is weak and not available so to support these applications DTN has characteristics like delay tolerance capacity in packet delivery, intermittent connectivity, scheduled contacts, high error rate and long or variable propagation delays. In DTN, to overcome weak end to end connectivity DTN nodes uses store-carry and forward protocol to relay messages from source to destination node. In DTN in- transits -packet we call it as bundle and bundle is opportunistically forwarded to the destination through intermediate nodes. In opportunistic routing, DTN use hypothesis of each node in DTN is cooperative with other nodes and willing to forward in-transit bundle to the destination nodes through intermediate nodes, with this hypothesis DTN perform well in routing but in real time applications of DTN, entities using DTN behaves rational and will not participate in bundle relaying to destination to reserve its resources like buffer space and energy. This behaviour of a entity or node is called as selfish behaviour of DTN node. Such selfish behaviour of node causes very large impact on bundle routing and decreases the performance of bundle delivery due to packet dropping by selfish node so single selfish node can jeopardise whole network and causes violation of DNT hypothesis. Hence, to overcome selfish behaviour of node we can use basic incentive scheme to promote selfish nodes to take part in bundle forwarding and selfish node detection algorithm to detect selfish node and ban and punish them in bundle routing protocol. We have implemented selfish node detection algorithm with incentive scheme and analysed it with different DTN routers for packet delivery ratio and number of selfish nodes detected.
Keywords: Delay Tolerant Network, Selfish Node, Selfishness