Performance Evaluation On Message Ferry-based Routing Protocols In Delay/disruption-tolerant Networks

Remarkable achievements have been made in DTNs (Delay/Disruption- Tolerant Networks) with the application requirements from some special scenarios, e.g., Space Network, Military ad hoc Network, MANET(Mobile Ad hoc Network), WSN(Wireless Sensor Network), underwater network, etc. However, in many realistic application environments, due to node mobility, nondeterministic communication, long link delay and frequent topology changes, it is still difficult to provide performance guarantee for data communication in DTNs.In this paper, we first review the research work on DTN routing, and using ONE (Opportunistic Networking Environment) simulator to test several typical DTN routing protocols for synthetically evaluating their performance. Based on this work, we study the effects of different performance factors including routing strategy, node density and others.After illustrating the basic idea of traditional ferry-based protocols, we argue how the typical characteristics of sparse DTNs affect the network performance, and the advantage and disadvantage of ferry scheme in DTN routing are summarized. Based on the analysis, we propose and implement a message ferry-based DTN routing method by combining the ferry scheme into existing DTN routing protocols, called Mixed Ferry Routing (MFR). We discuss how to deploy the ferries into the network. In MFR, ordinary nodes and ferry nodes in the network run the same routing protocol and cooperate for data relaying and forwarding, which makes it more practical for data communication. By this way, the communication probability between nodes as well as message delivery opportunity can be increased effectively, which enhances the network performance.Finally, we use ONE simulator to construct a simulation environment according to some practical sparse DTN applications. We compare the network performance between the traditional ferry routing scheme and our mixed-ferry routing protocol. The experimental results show that mixed-ferry routing can not only effectively improve the performance of various DTN routing protocols but also get excellent results in message delivery ratio, packet loss ratio and communication overhead against the traditional ferry routing scheme.