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 in DTNs is a considerably more difficult problem compared to that in 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) strategies. Then we focus on studying two DT-Multicast routing schemes: Dynamic Tree Based Routing (DTBR) and On-demand Situation-aware Multicast (OS-Multicast), which address the challenges of utilizing opportunistic links to conduct dynamic multicast structures in DTNs. Performances of different strategies are then evaluated by simulations, including applying the real-world DTN traces. Our results show that OS-Multicast and DTBR can achieve higher message delivery ratio than that of using U-Multicast and ST-Multicast strategies. Also, to get better performance, we recommend that system designers select OS-Multicast when the source traffic rate is low.