The Open Shortest Path First (OSPF) protocol is a hierarchical interior gateway protocol (IGP) for routing in Internet Protocol, using a link-state in the individual areas that make up the hierarchy. A computation based on Dijkstra's algorithm is used to calculate the shortest path tree inside each area. The current version, Version 3, defined in RFC 2740 , supports IPv6 as well as IPv4, has various internal enhancements, and is backwards compatible with the earlier version, .
See more at Wikipedia.org...