Social-Distance based anycast routing in Delay Tolerant Networks

Abstract

Delay Tolerant Networks (DTNs) are sparse mobile ad-hoc networks in which there is typically no complete path between the source and destination. Anycast is an important group communication paradigm for numerous DTN applications such as resource discovery and information exchange in emergency or crisis situations. While anycasting has been studied extensively in the context of the Internet and Mobile Ad-Hoc Networks (MANETs), efficient anycasting in DTNs is a significantly different and challenging problem due to frequent partitions and intermittent connectivity among nodes. In this paper, we propose a single-copy anycast routing strategy in which the current carrier forwards the message to an encounter node with a higher Anycast Social Distance Metric (ASDM). We formulate ASDM based on the multi-hop social distances to anycast group members. ASDM balances the trade-off between a short path to the closest, single group member and a longer path to the area where many other group members reside. That is, it optimizes both the efficiency and robustness of message delivery. We derive the social distances from the multi-hop delivery probabilities over the most probable path in the social contact graph. Through extensive simulation studies using a real-world mobility trace, we show that our scheme achieves a high delivery ratio, low delay, and low transmission cost compared to other anycast strategies.