<P> 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). 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 supports the Classless Inter-Domain Routing (CIDR) addressing model . </P> <P> OSPF is a widely used IGP in large enterprise networks . IS - IS, another LSR - based protocol, is more common in large service provider networks . </P>

What is routing algorithm used by ospf routing protocol