It is an Internet routing protocol that scales well, can route traffic along multiple paths, and uses knowledge of an Internet's topology to make accurate routing decisions.
OSPF is Open shortest path first basically comes into the category that uses link state as the routing info communication. OSPF is used in a particular Autonomous system not used on the internet but its limited to internal routing in an organization.
On top of OSPF we run BGP to facilitate the communication across multiple autonomous systems in the internet
