Linux® Routing

Open Shortest Path First (OSPF)

The Open Shortest Path First (OSPF) routing protocol is a link-state protocol. This term refers to the reduced amount of information that OSPF keeps track of compared to a protocol such as RIP-2. A link-state protocol uses an entirely different method of choosing routes than a distance-vector protocol.

The Algorithm

Link-state protocols use one of a collection of Shortest Path First (SPF) algorithms. Once again, these algorithms are based on solving graphing problems and then were applied to networking. In the case of OSFP, the algorithm behind the method is the Dijkstra algorithm. Here again, we start with a collection of points. We’ll use the same set shown previously in Figure 1.5.

You must define which points ...