Use the information in these sections to help you understand Open Shortest Path First (OSPF).
OSPF is an Interior Gateway Protocol (IGP) that distributes routing information between routers that belong to a single autonomous system (AS). Intended for use in large networks, OSPF is a link-state protocol that supports IP subnets, Type of Service (TOS)-based routing, and tagging of externally-derived routing information.
For information about the Border Gateway Protocol (BGP), see BGP.