Design and evaluation of efficient routing protocol in delay tolerant network

Abstract

Delay Tolerant Network (DTN) is a new up and coming era of intermittently connected wireless networks. Such network operates in extreme environment where end-to-end communication is area under discussion to delays and disruption. They may suffer from frequent partitions. There are many real-life applications where wireless nodes either mobile or stationary are forced to undergo extreme operational conditions and wait for extended intervals of time before being able to forward their data to next hops. These applications contain the representative of DTN which includes sensor based networks using scheduled intermittent connectivity, terrestrial wireless networks that cannot ordinarily maintain end-to-end connectivity, satellite networks with moderate delays and periodic connectivity, under water acoustic networks with moderate delays and vehicular networks with cyclic but non deterministic connectivity. newlineThe major issues in DTN is routing of packets from source to destination in an effective manner. Because majority of the time is spent for finding the right paths and there are many cases where there is no clear path from source to destination due to the mobility condition of nodes. But in DTN, if the communication is in process and link goes then the data get stored in the sender/ receiver nodes buffer rather being lost. This is because of the message forwarding is done by replicating the message stored in their buffer. Routing of packets in DTN is done hop by hop, in which the selection of next hop is done dynamically as per the application scenario as well as algorithm used. Depending upon the algorithm used, the transmission of message in DTN can either be done by replicating the message or by forwarding it. However, existing routing protocols in DTNs are still having limitations; such a slack of synchronous end-to-end connectivity in carrying the messages and forwarding them opportunistically without encountering, and so on. This could result in long transmission delay and lower message delivery rate. Moreover, DTN s changing network topology, lower delivery ratio and higher delay also affect the routing process. newline