Open Shortest Path First (OSPF) is an interior gateway protocol (IGP) that is most often used to dynamically manage network routes in large enterprise networks. It determines routes dynamically by obtaining information from other routers and advertising routes to other routers by way of Link State Advertisements (LSAs). The information gathered from the LSAs is used to construct a topology map of the network. This topology map is shared across routers in the network and used to populate the IP routing table with available routes.

Changes in the network topology are detected dynamically and used to generate a new topology map within seconds. A shortest path tree is computed of each route. Metrics associated with each routing interface are used to calculate the best route. These can include distance, network throughput, link availability etc. Additionally, these metrics can be configured statically to direct the outcome of the OSPF topology map.

The Palo Alto Networks^® implementation of OSPF fully supports the following RFCs:

The following topics provide more information about the OSPF and procedures for configuring OSPF on the firewall: