Routing in Opportunistic Networks
In the previous chapter, we described the distinguishing features of opportunistic networks, namely, sparse node density, lack of network-wide connectivity, and unique role of node mobility as communication means within the network. Given these features, the mechanisms governing message routing in an opportunistic network are very different from those typical of other types of wireless networks. In particular, lack of end-to-end communication paths between source and destination of a message forces the routing protocol to exploit the temporal dimension and node mobility to eventually deliver a message to the intended destination.
In this chapter, we will first describe the basic store, carry, and forward mechanism at the heart of any opportunistic network routing protocol, and present a few representative routing protocols for opportunistic networks. We will then carefully discuss the role of mobility in message routing, and define the most important mobility metrics used in the characterization and analysis of node mobility in opportunistic networks.
Given the lack of end-to-end communication paths between source and destination of a message, the mechanisms at the basis of routing in opportunistic networks are radically different from those used in other types of wireless networks, such as route discovery/route reply messages, routing tables, and so on. In opportunistic networks, ...