Wireless Routing Protocol


The Wireless Routing Protocol is a proactive unicast routing protocol for mobile ad hoc networks.

Description

Method

Each node implementing WRP keeps a table of routes and distances and link costs. It also maintains a 'message retransmission list'.
Routing table entries contain distance to a destination node, the previous and next nodes along the route, and is tagged to identify the route's state: whether it is a simple path, loop or invalid route.
The link cost table maintains the cost of the link to its nearest neighbors, and the number of timeouts since successfully receiving a message from the neighbor.
Nodes periodically exchange routing tables with their neighbors via update messages, or whenever the link state table changes. The MRL maintains a list of which neighbors are yet to acknowledged an update message, so they can be retransmitted if necessary. Where no change in the routing table, a node is required to transmit a 'hello' message to affirm its connectivity.
When an update message is received, a node updates its distance table and reassesses the best route paths. It also carries out a consistency check with its neighbors, to help eliminate loops and speed up convergence.

Shortcomings

WRP has the same advantage as that of DSDV. In addition, it has faster convergence and involves fewer table updates. But the complexity of maintenance of multiple tables demands a larger memory and greater processing power from nodes in the ad hoc wireless network. At high mobility, the control overhead involved in updating table entries is almost the same as that of DSDV and hence is not suitable for highly dynamic and also for a very large ad hoc wireless network.
WRP requires large memory storage and resources in maintaining its tables. The protocol is not suitable for large mobile ad hoc networks as it suffers from limited scalability.