DSG-PC: Dynamic social grouping based routing for non-uniform buffer capacities in DTN supported with periodic carriers

Abstract

Routing a message in networks that are dynamic in nature with time varying partially connected topology has been a challenge. The heterogeneity of the types of contacts available in such a network also adds to complexity. In this paper we present an approach to transfer messages in disruption/delay tolerant network when there is only intermittent connectivity between the nodes. Most of the existing approaches exploit either the opportunistic contacts and transfer messages using the probabilities of delivering a message or use periodic contacts. In addition to opportunistic contacts, we also have scheduled carriers that are available periodically. Scheduled carriers guarantee delivery of the messages to the base station, however, it may have an added delay. If a message can tolerate the delay through the scheduled carrier, it waits else it may be forwarded to an opportunistic contact. We define a utility function for a node to decide whether to forward the message to an opportunistic contact or to a scheduled contact. This is an improvement over routing through opportunistic contacts that exploits social behavior of the nodes as in [2]. We compare performance of our approach with [2] on message delivery ratio, message delay and message traffic ratio (number of messages forwarded / number of messages delivered) and found that our algorithm outperforms [2] on all the three metrics. We also studied the impact of initializing the probabilities of the nodes proportional to the varying buffer size in [2]. It was found that delivery ratio increased significantly without increasing the message traffic ratio and delay.