Adaptation of spray phase to improve the binary spray and Wait routing in Delay Tolerant Networks

Delivering messages in Delay Tolerant Networks is a nontrivial challenge due to its sparse nature and intermittent connectivity. Therefore efficient routing of messages is vital for these networks. In this work, we aim to adapt the spray phase of the Binary Spray and Wait routing scheme in Delay Tolerant Networks to avoid large communication overhead suffered by the scheme. We define an adaptive spraying scheme to allow nodes to switch to the wait phase without lingering the spray phase unnecessarily. Binary Spray and Wait routing permits nodes to enter the wait phase when the remaining number of copies of a message reaches one. However, we permit nodes to consider the time to live value of a message instead of the number of copies to enter the wait phase. We formulate an equation to obtain a switch value to compare against the time to live value of a message to migrate to the wait phase. Furthermore, we compare our scheme with that of other schemes through simulations. Simulation results show that our proposed adaptive spraying scheme performs better than that of others in different network scenarios.