Gugrajah_Yuvaan_ Ramesh_2003.pdf

Routing Protocols for Ad Hoc Networks
Chapter 2
Chapter 2
ROUTING PROTOCOLS FOR AD HOC NETWORKS
2.1. Introduction
Routing is the function of the network that detennines the path from a source to a
destination for the establishment of viable communication. Ad hoc networking
allows users to access the network independent of location and movement, but this
mobility allows the topology of the network to change dynamically and
unpredictably. The problem is amplified because routes often consist of multiple
hops due to intentionally short transmission ranges that reduce interference and
power consumption for nodes in the network. Several approaches have been
proposed to provide routing for ad hoc networks by adapting techniques developed in
wired networks. This chapter provides a survey of the existing schemes proposed for
end-to-end routing in ad hoc networks.
Section 2.2 introduces unicast protocols. The unicast protocols include traditional
distance vector and link state routing, as well as newer path-finding routing protocols
and on-demand routing protocols. Unicast protocols can be divided into proactive or
table-driven protocols, described in Section 2.2.1 and the reactive or on-demand
routing protocols described in Section 2.2.2. Modifications and hybrid varieties 'of
the two types of unicast protocols have also been proposed and are discussed in
Sections 2.2.3 to 2.2.7.
Multicast routing protocols include variations on the shortest path tree algorithms,
multicast trees and mesh-based protocols. In graph theory a tree is a path that does
not contain any loops. Since this dissertation is focused on unicast routing protocols,
multicasting is briefly reviewed in Section 2.3.
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