摘要：Delay tolerant networks (DTNs) are a special type of wireless mobile networks which may lack continuous network connectivity. Multicast supports the distribution of data to a group of users, a service needed for many potential DTNs applications. While multicasting in the Internet and mobile ad hoc networks has been studied extensively, due to the unique characteristic of frequent partitioning in DTNs, multicasting in DTNs is a considerably different and challenging problem. It not only requires new destinations of multicast semantics, but also brings new issues to the design of routing algorithms. In this paper, we propose new forwarding models for DTNs multicast and develop several multicast forwarding algorithms. We use delegation forwarding (DF) in DTNs multicast and compare it with single and multiple copy multicast models, which are alsoproposed in this paper. From the analytical results, we have the following conclusions: (1) Although the single copy model has the smallest number of forwardings, its latency is much longer than the other two models. (2) Among these three models, the delegation forwarding model has the least delay. The effectiveness of our approach is verified through extensive simulation both in synthetic and real traces.
