Open Shortest Path First - OSPF

OSPF is a link-state routing protocol you use between routers to exchange information about routes and the cost to reach an intended destination. OSPF routers exchange information about their links, prefixes, and associated cost with LSAs. This topology information builds a topology database. Each router within an area has an identical database and calculates its own routing table using SPF algorithm. Cumulus Linux uses the SPF algorithm any time there are changes to routing information in the network. OSPF uses the concept of areas to try and limit the size of the topology database on different routers. The routers that exist in more than one area are ABRs, which simplify the information in LSAs when advertising them from one area to another. ABRs are the routers in OSPF that implement route filtering or route summarization.

Cumulus Linux supports:

• Open Shortest Path First v2 - OSPFv2 for IPv4.
• Open Shortest Path First v3 - OSPFv3 for IPv6.