Delay Tolerant Routing and Applications
The fundamental goal of any communication network is to have the messages delivered to their corresponding destinations. In conventional networks, such as MANETs, determining a routing path with optimum cost is rather easy. However, such approaches become difficult in DTNs/OMNs due to their unique characteristics, as noted in the previous chapter. The network topology of DTNs/OMNs is not only highly dynamic, but also exhibits high degree of network partitioning. In particular, the concept of end-to-end communication paths practically ceases to exist therein. To overcome such issues and constraints, several schemes have been proposed in the literature to achieve efficient routing in DTNs/OMNs. In this chapter, we take a look at a broad category of such protocols. A common characteristic of all these routing protocols is that they are replication based, i.e., they create multiple copies of a message in the OMN concerned. However, some of them attempt to restrict the extent of replication in different ways to achieve efficiency. We, then, present a set of commonly used metrics for measuring the performance of OMNs. Subsequently, we discuss about real-life traces that are increasingly being used with network simulations nowadays. Finally, we conclude this chapter by retrospecting some of the applications of DTNs.