HVR: History-Based Vector Routing for Delay Tolerant Networks

In delay tolerant networks (DTNs) with frequent network partitioning, routing packets is a challenge, because the successful establishment of an end-to-end path between source and destination nodes is not guaranteed. Typical routing protocols for DTNs depend on data replications over multiple paths for reliable data delivery. Since they invoke a lot of replicated packets, our previous work introduced a Vector Routing protocol utilizing the vector of node movement in order to reduce such replications. In this paper, we extend the previous work and propose a more efficient Vector Routing protocol to exploit some features of history-based routing protocols where packets are forwarded to nodes with higher probability to meet their destination nodes. Unlike the existing protocols where the number of nodal encounters is used to calculate the probability of forwarding, our proposed protocol allows a node to maintain the vector information of other nodes that it has met and share this information with other nodes. Using the history information, a node predicts the location area of each packet's destination node in order to perform more accurate forwarding. The ns-2 simulations using random waypoint and Manhattan mobility models verify that our protocol achieves better performance in terms of less amount of traffic incurred without loss of packet delivery ratio.