Open Shortest Path First
From Computer History Wiki
Open Shortest Path First (usually known as OSPF) is a routing protocol for the TCP/IP protocol suite. It is an IGP, and can be used either on pieces of the Internet, or on disconnected internets.
It is a link state routing protocol; it was mostly inspired by the first LS routing protocol, that used on the ARPANET, but it also 'borrowed' a few ideas from IS-IS.