An ad hoc network is a collection of inter-connected,
arbitrarily arranged mobile hosts and routers, with a topology that changes
unpredictably and relies on no fixed infrastructure or central coordinating
entity. Nodes communicate directly between one another over wireless channels.
Because the transmission range of these nodes is limited, a routing protocol is needed to enable communication between them. However,
because of the portable nature of the wireless devices and the wireless
transmission medium, ad hoc networks have many characteristics that render
routing protocols designed for wired networks inapplicable. The primary goal of
an ad hoc network routing protocol is correct and efficient route establishment
between a pair of nodes so that messages may be delivered
in a timely manner. Route construction should be done
with a minimum of overhead and bandwidth consumption.
This report examines twelve unicast and four multicast routing protocols for ad hoc networks by presenting their characteristics and functionality, and then provides a comparison, performance evaluation and discussion of their respective strengths and weaknesses. The report concludes with some observations on the open areas for further investigation and suggestions to address some of these issues.