Categorization of copies to improve the performance of routing schemes in delay tolerant networks

Optimizing the three most important network performance parameters i.e. Delivery probability, Overhead ratio, and Delay is challenging in Delay Tolerant Networks (DTN) due to high occurrences of network partitioning in these networks. Owing to the partitioning nature efficient routing or dissemination of messages is important in DTN. In this paper, we focused to improve the spray phase of Binary Spray and Wait routing scheme, an efficient routing scheme in DTN, by dividing the number of copies of a message in different categories. The proposed scheme provides higher delivery probability and lower delay for messages while keeping the overhead ratio low. Here, an adaptive spraying scheme is used combining the regular binary spraying and performance based spraying of a message in each node. Thus, each message is forwarded starting with the binary followed by an adaptive spraying technique depending on the time to live (TTL) value of that message. We also formulate an equation to permit a node to calculate a switch value for each message it carries. Later, the switch value is compared to the TTL of the message to toggle to the wait phase for that particular message instead of the number of copies of the message reaching to one. Simulation results show that our adaptive scheme has better delivery and delay performance than that of other schemes.