Routing Techniques for Opportunistic Network

Abstract

An opportunistic network is a variant of a delay tolerant network (DTN) that involves routes which are built dynamically. It is a type of challenged network and exhibits an overlay architecture where it acts as a blanket over the existing networks. Here the message is forwarded differently than the way the messages are delivered on the Internet. A DTN is delay prone, which means a message may take a lot of time to be delivered to the intended destination. Examples of DTN are an interplanetary network, underwater acoustic sensor networks and the like. The messages communicated between the sender and the destination(s) are routed using any node as the next hop, opportunistically, if it ensures carrying the message closer to the destination node. So, in an opportunistic network, every single node acts as a gateway. This chapter discusses routing strategy in an opportunistic environment. The routing algorithms presented here employ social characteristics, a model mobility pattern such that performance is increased in terms of delivery ratio and delivery latency. Analysis is also elaborated of the routing protocols of opportunistic networking in order to investigate route discovery and maintenance, minimizing power consumption, and maintaining QoS guarantees. The routing algorithms are mostly structured to comply to the basic characteristics of such networks as the following: High and variable latencies in the message deliveries. Tolerance of a high error rate. An end-to-end path between the source and destination that infrequently exists. A highly dynamic connection. Limited physical security. While mobility of nodes is considered a major issue for typical networks such as mobile ad hoc networks (MANETs) and VANETs; for the opportunistic networks; mobility becomes helpful for communication to take place between nodes through contact opportunities. Areas where the opportunistic network is used efficiently include the following: Sami Network Connectivity (SNC) Project [1] for establishing Internet connectivity in remote areas. Wildlife tracking applications (ZebraNet) [2]. Providing connectivity to rural and developing areas [3] where conventional networks do not exist. Disaster-affected areas where networks are not available [4]. Military battlefield networks [3].