Anycast Routing in Probabilistically Contacted Delay Tolerant Networks

Delay tolerant networks (DTNs) experience frequent and long lasting network disconnection due to various reasons such as mobility, sleep scheduling, etc. Anycast routing is an important and challenging problem in DTNs. In this paper, we study the single-copy message anycast routing problem in probability-contacted DTNs. We first define a novel metric MDRA (Maximum Delivery Rate for Anycast) to indicate the maximum successful probability of anycast routing, and then propose the MDRA routing algorithm based on this metric. Rigorous theoretical analysis shows that such a anycasting strategy is the optimal. Moreover, we propose an efficient algorithm to compute the MDRA values of all nodes. The computation overhead of this algorithm only is O(|S|²|T|) where |S| is the number of nodes in the network and |T| is the TTL (Time To Live) value of messages. In addition, through extensive simulations based on real DTN traces, we demonstrate that our algorithms can significantly perform better than the previous ones.