Protocol for the OLSR Routing

The Optimized Link State Routing Protocol (OLSR) applies wired network methods to mobile ad-hoc networks (MANETs) -- which are wireless networks. "Link State" routing is "proactive," which means it maintains a table of possible routes.

Function

• In wired networks, Link State routing ranks routes according to performance (the state of each link). In MANETs, individual nodes do not need to communicate through a router, but instead contact each other directly. This creates many possible routes and would make the routing table very large. OLSR reduces table size by ignoring many of the nodes in its neighborhood.

Features

• A wireless-enabled device, like a laptop, sends out "Hello" messages to its signal footprint. All the other wireless devices reply, reporting on what other devices they can contact. The replying nodes are sorted, removing those nodes that the original nodes can contact. This leaves a list of "two hops" nodes, which the originator can only contact through another device.

Implementation

• The routing method decides which of its neighbors, within its signal range, offers the best path to the two hop nodes. These are called multipoint relays (MPRs), and the rest of the nodes are deleted from the database.