Open Shortest Path First

Open Shortest Path First
Communication protocol
PurposeRouting protocol
Introduction1989 (1989)
RFC(s)1131, 1247, 1583, 2178, 2328, 3101, 5709, 6549, 6845...
OSPF for IPv6
Communication protocol
Introduction1999 (1999)
RFC(s)2740, 5340, 6845, 6860, 7503, 8362...

Open Shortest Path First (OSPF) is a routing protocol for Internet Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single autonomous system (AS).

OSPF gathers link state information from available routers and constructs a topology map of the network. The topology is presented as a routing table to the internet layer for routing packets by their destination IP address. OSPF supports Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6) networks and is widely used in large enterprise networks. IS-IS, another LSR-based protocol, is more common in large service provider networks.

Originally designed in the 1980s, OSPF version 2 is defined in RFC 2328 (1998).[1] The updates for IPv6 are specified as OSPF version 3 in RFC 5340 (2008).[2] OSPF supports the Classless Inter-Domain Routing (CIDR) addressing model.

  1. ^ J. Moy (April 1998). OSPF Version 2. Network Working Group. doi:10.17487/RFC2328. STD 54. RFC 2328. Internet Standard 54. Obsoletes RFC 2178. Updated by RFC 5709, 6549, 6845, 6860, 7474 and 8042.
  2. ^ R. Coltun; D. Ferguson; J. Moy (July 2008). A. Lindem (ed.). OSPF for IPv6. Network Working Group. doi:10.17487/RFC5340. RFC 5340. Proposed Standard. Obsoletes RFC 2740. Updated by RFC 6845, 6860, 8362, 7503 and 9454