Open Shortest Path First

Open Shortest Path First (OSPF) is a link-state routing protocol for Internet Protocol (IP) networks. It uses a link state routing algorithm and falls into the group of interior routing protocols, operating within a single autonomous system (AS). It is defined as OSPF Version 2 in RFC 2328 (1998) for IPv4. The updates for IPv6 are specified as OSPF Version 3 in RFC 5340 (2008).

OSPF is perhaps the most widely used interior gateway protocol (IGP) in large enterprise networks. IS-IS, another link-state dynamic routing protocol, is more common in large service provider networks. The most widely used exterior gateway protocol is the Border Gateway Protocol (BGP), the principal routing protocol between autonomous systems on the Internet.

Internet protocols
Application layer
  • DHCP
  • DHCPv6
  • DNS
  • FTP
  • HTTP
  • IMAP
  • IRC
  • LDAP
  • MGCP
  • NNTP
  • NTP
  • POP
  • RPC
  • RTP
  • RTSP
  • SIP
  • SMTP
  • SNMP
  • SOCKS
  • SSH
  • Telnet
  • TLS/SSL
  • XMPP
  • (more)
Transport layer
  • TCP
  • UDP
  • DCCP
  • SCTP
  • RSVP
  • (more)
Routing protocols *
  • BGP
  • OSPF
  • RIP
  • (more)
Internet layer
  • IP
    • IPv4
    • IPv6
  • ICMP
  • ICMPv6
  • ECN
  • IGMP
  • IPsec
  • (more)
Link layer
  • ARP/InARP
  • NDP
  • Tunnels
    • L2TP
  • PPP
  • Media access control
    • Ethernet
    • DSL
    • ISDN
    • FDDI
  • (more)
* Not a layer. A routing protocol belongs either to application or network layer.

Read more about Open Shortest Path First:  Overview, Neighbor Relationships, Area Types, Path Preference, OSPF Router Types, Designated Router, OSPF V3 Packet Formats, OSPF in Broadcast and Non-broadcast Networks, Implementations, Applications

Famous quotes containing the words open, shortest and/or path:

    “Rats!
    They fought the dogs and killed the cats,
    And bit the babies in the cradles,
    And ate the cheeses out of the vats,
    And licked the soup from the cooks’ own ladles,
    Split open the kegs of salted sprats,
    Made nests inside men’s Sunday hats,
    And even spoiled the women’s chats
    By drowning their speaking
    With shrieking and squeaking
    In fifty different sharps and flats.”
    —Robert Browning (1812–1889)

    “The shortest answer is doing.”
    —English proverb, collected in George Herbert, Jacula Prudentum (1651)

    “I love to weigh, to settle, to gravitate toward that which most strongly and rightfully attracts me;Mnot hang by the beam of the scale and try to weigh less,—not suppose a case, but take the case that is; to travel the only path I can, and that on which no power can resist me. It affords me no satisfaction to commence to spring an arch before I have got a solid foundation.”
    —Henry David Thoreau (1817–1862)