CTMR-collaborative time-stamp based multicast routing for delay tolerant networks in post disaster scenario

Due to high chances of loss in connectivity, a Delay Tolerant Network (DTN) can be used to communicate between nodes without having any fixed connection between the source and destination. A Post Disaster Scenario presents a very challenging environment to communicate in and to analyze those situations is even a harder task to accomplish. It necessitates very efficient co-ordination to successfully accomplish situation analysis and resource management. Efficient co-ordination between relief and rescue teams in such situations can be achieved through multicasting, since it allows sending single packet to multiple destinations. Though multicasting in MANET has been studied extensively, but the implementation of efficient multicasting in DTN is a very challenging task due to its frequent partitioning characteristic. In this work a Collaborative Time-Stamp based Multicast Routing (CTMR) Protocol has been proposed. The messages have been implemented using customized bundles, where the destination of a multicast bundle consists of a group of nodes. Node grouping mechanism has been adopted to suit a post disaster condition. Collaborative bundle creation and selection mechanism has been utilized so that localized redundant information flow is minimized. Suitable time and space limits have been selected to further reduce redundancy. The group forwarding strategy is based on probabilistic measures calculated using historical encounter records, and on a multiple parameter priority queue. This protocol has been implemented in the ONE simulator and is compared with other existing unicast and multicast routing protocols on important routing parameters like delivery ratio and delivery delay. Comparison results show that CTMR can be a novel efficient solution to multicasting in a DTN.