OSPF General

OSPF is a link-state protocol based on Dijkstra shortest path first algorithm.

Routers running OSPF neighbour with routers that are directly connected, with the same network address. Link State Advertisements (LSA) are sent between routers to create a topology table, which should be consistant on all routers within the same area.

OSPF populates the following three tables:

- Neighbour table (show ip ospf neighbour
- Topology table (sh ip ospf database)
- Routing table (sh ip route)

Router#sh run sec router ospf
router ospf 72
log-adjacency-changes
network 172.16.0.0 0.0.0.255 area 51
network 192.168.0.0 0.0.0.255 area 51