1.11 ROUTING PROTOCOLS USED IN MANET

PROACTIVE ROUTING (TABLE- DRIVEN) PROTOCOLS:

In this protocol, all the nodes continuously search for routing related information within a network. Each node maintains one or more routing tables which represents the entire topology of the network. These tables are updated regularly so that when a route is needed, these tables will be checked to find out whether the routing information is already available or not. If any node already knows the path for sending information, then the latency will be low. However, when the nodes are mobile then the cost of maintaining all topology information will be very high.

REACTIVE ROUTING (ON-DEMAND) PROTOCOLS:

Routing information is collected only when there is a need. …show more content…
It is designed for use in multihop ad hoc networks of mobile nodes. It allows the network to be self-organizing and self-configuring. It does not need any existing network infrastructure or administration. DSR is composed of the two mechanisms

(1) Route Discovery

(2) Route Maintenance, These mechanisms allow the nodes to discover and maintain the routes between the source and the destination in the network. Since DSR is based on the concept of source routing it has a unique advantage. Routing loops, either short – lived or long – lived, cannot be formed and also they can be immediately detected and eliminated as the route is part of the packet itself,. This property enables the protocol to be used in a variety of useful optimizations.

ROUTE DISCOVERY

In the route discovery process, first the source node broadcasts a Route Request packet which can be received by all neighbor nodes within its wireless transmission range. The Route Request contains the destination host address, referred to as the target of the route discovery, the source address, a route record field and a unique identification number. When the route is found the source node receive a Route Reply Packet with a list of network nodes through which it should transmit the data