Region Topology Based Route Design for Multiple Ferries in DTNs

In delay tolerant networks (DTNs), message ferries exploit controlled mobility to forward messages following specific routes. One of the key challenges is how to design ferry routes to achieve desired connectivity properties and store-and-forward performance. There are some attempts at designing appropriate ferry routes, but the region topology, which denotes the adjacency relationships of ferry regions and affects the message forwarding efficiency among different ferry regions, has not been draw attention. The concept of ferry region indicates the region which a ferry route covers. In this paper, we concentrate on the region topology based route design (RTRD) for multiple ferries. RTRD dose not design the details of specific routes for each ferry independently, instead, it focuses on the interactivity of neighbor-ferries and aims to get appropriate region topologies of ferries. We analyze message delivery delay and buffer requirement in typical region topologies grid, cellular and wheel. The results show that the region topology has a significant impact on network performance, and with given performance requirements, an appropriate region topology should be chosen before designing the route details of ferries.