Fuzzy assisted dynamic message replication and routing in delay tolerant networks.

In a delay tolerant network (DTN) nodes are scattered and intermittently connected. In this network end-to-end path cannot be assumed to be available. Routing protocols in DTNs usually replicate message in the network to transmit the message toward its destination. Managing message replication and distribution, and finding appropriate relay nodes due to the lack of timely and precise information is a major challenge. Existing multi-copy routing protocols when replicate and distribute copies of message don't consider some capabilities of nodes as the power to take and carry copies, this may lead to delays in delivering the message. In this paper, we proposed a multi-step routing protocol for DTNs. In each routing step, our protocol first dynamically determines the needed number of copies and also share of nodes from these copies. It makes decisions with the help of an attribute named Replication Capability Rate (RCR). The fuzzy system provides RCR based on the capability of nodes as power and property of message as time to live. Then, protocol sprays copies until remaining single copy in the buffer of the node. Finally, the single copy of the message is exchanged between nodes according to the encounter frequency. Experiment results show that our protocol significantly decreases the average delay and keeps delivery probability high, in comparison with well-known protocols. [ABSTRACT FROM AUTHOR]