Performance comparison of different multicast routing strategies in disruption tolerant networks

Disruption Tolerant Networks (DTNs) technologies are emerging solutions to networks that experience frequent partitions. As a result, multicast design for DTNs is a considerably more difficult problem compared to that of Internet and mobile ad hoc networks. In this paper, we first investigate three basic DTN multicast strategies, including unicast-based multicast (U-Multicast), static-tree-based multicast (ST-Multicast) and dynamic-tree-based multicast (DT-Multicast). Then we focus on studying two DT-Multicast methods: Dynamic Tree Based Routing (DTBR) and On-demand Situation-aware Multicast (OS-Multicast), which address the challenges of utilizing opportunistic connectivity to conduct one-to-many data communication in DTNs. Performances of different multicast approaches are evaluated by simulations. Our results show that DT-Multicast approaches can achieve higher message delivery ratio than the other strategies. Also, to get better performance, we recommend that system designers select OS-Multicast when the traffic load is low and select DTBR when the traffic load is high respectively. Keywords-disruption/delay tolerant networks; intermittently connected networks; dynamic multicasting; performance evaluation