OSPF
Support for the Open Shortest Path First (OSPF) protocol (as defined in RFC 2328) is also included. OSPF is a router protocol used within larger autonomous system networks in preference to RIP, an older routing protocol that is installed in many of today's corporate networks. Like RIP, OSPF is designated by the Internet Engineering Task Force (IETF) as one of several Interior Gateway Protocols (IGPs).
Using OSPF, a host that obtains a change to a routing table or detects a change in the network immediately multicasts the information to all other hosts in the network so that all will have the same routing table information. Unlike the RIP in which the entire routing table is sent, the host using OSPF sends only the part that has changed. With RIP, the routing table is sent to a neighbor host every 30 seconds. OSPF multicasts the updated information only when a change has taken place, making its use of bandwidth resources considerably more efficient.