When many OSPF routers are part of the same network, information about all of the routes in a network are learned by all of the OSPF routers within that network—technically called an area. (We’ll talk more about the area as we go on).

Each OSPF router passes along information about the routes and costs they’ve heard about to all of their adjacent OSPF routers, called neighbors.

OSPF routers rely on cost to compute the shortest path through the network between themselves and a remote router or network destination. The shortest path computation is done using Djikstra’s algorithm. This algorithm isn’t unique to OSPF. Rather, it’s a mathematical algorithm that happens to have an obvious application to networking.