VxWorks retrieves routing information by searching for it in a routing table. To set up and manage this table manually, use the routines routeAdd( ) or mRouteAdd( ). However, because the network environment is constantly in flux, the information in the routing table grows obsolete as machines join or leave the network. To update the routing table dynamically, VxWorks supports two protocols:

RIP, the older and simpler protocol, comes bundled with VxWorks, and is intended for small to medium-sized networks. OSPF is a separately purchasable option for use with VxWorks. OSPF is superior to RIP in many ways. For example, OSPF is a link-state protocol, not a distance-vector protocol, like RIP. The messages from a distance-vector protocol contain a vector of distances (a hop count). Each router uses these distance-vectors to update its routing tables.

A router running a link-state protocol, such as OSPF, is more active about getting the information it needs. An OSPF router actively tests the status of its links to its neighbors, and then shares this information with other OSPF routers. One result of this more active approach is faster network stabilization after a change, such as the loss of a router or a link. Unfortunately, this enhanced stabilization comes at the price of increased complexity. As a result, it requires considerably more thought to configure OSPF correctly.