Limiting the number of message copies in delay tolerant networks

Abstract

One of the basic assumptions of traditional ad hoc network was that there always exists a complete connected path between the endpoint nodes. However, this assumption cannot be always true in case of DTN(Delay Tolerant Networks). Because of the absence of predetermined path, most proposed DTN routing protocols make multiple copies of a message and send them through a number of routes. Although these multi-copy schemes can achieve both higher delivery ratio and less delay than the single-copy schemes, existing DTN routing protocols make too many copies without proper control and result in performance degradation. To solve this problem, we present a way to calculate the optimal number of copies in DTN which achieves the maximum delivery ratio. We also propose a routing protocol that produces the calculated number of copies for each message. Through the simulations, it is shown that the proposed scheme achieves higher delivery ratio with significantly less resource consumption than the earlier presented multi-copy routing protocols.