Mobile Ad Hoc Routing Protocols

There are two categories of routing protocols: table-driven and on demand-routing. In table-driven routing protocols routing information is periodically advertised to all nodes so all nodes have an up-to-date view of the network. Alternatively, on-demand routing protocols only discovers a new route when it is required to. Hybrid routing protocols also exist and they try to achieve an efficient balance between both categories of protocols [3]. Table shows a comparison between the two methodologies. It is clear that on-demand protocols are more suited for mobile handheld devices as network bandwidth and battery power is limited. Some on-demand routing protocols are discussed in the sections below.

Table: Comparison of table-driven and on-demand protocols

	Table-driven	On-demand
Availablilty of Routing Information	Immediately from route table	After a route discovery
Route Updates	Periodic Advertisments	When requested
Routing Overhead	Proportional to the size of the network regardless of network traffic	Proportional to the number of communicating nodes and increases with increased node mobility