An Enhanced Spray-Copy-Wait DTN Routing Using Optimized Delivery Predictability

Abstract

DTN-Delay Tolerant Network works well in the severe conditions where other wireless ad hoc networks fail to exist. It works well even where there does not exist any end to end connectivity i.e. intermittent connectivity. It works on the principle similar to postal system i.e. store-carry-and-forward; which makes it possible for DTN to work in the regions of intermittent connectivity. It is implemented by bundle protocol. The bundles of message are replicated, forwarded to the intermediate nodes with the help of various routing and replication strategies offered by various routing protocols of DTN. Spray-and-Wait routing protocol is good in providing a replication strategy but lacks in routing strategy; while PRoPHET routing protocol proves a very good routing strategy and therefore a hybrid of both can intelligently route sufficient number of copies in the network. Major problem of spray-and-wait routing protocol i.e. explicitly deciding the exact number of copies i.e. L to be initially set. The goal of this research is to increment the L if copies are not sufficient and to forward copies only based on the optimized threshold and remove garbage messages by negative packet technique. From evaluation of experiments, we show that the proposed method works really well for least message generation interval, and gives sufficiently good optimized results for both arrival rate and overhead.