Open Shortest Path First (OSPF) is a link-state Interior Gateway Protocol (IGP) developed by the Internet Engineering Task Force (IETF).
OSPF Version 3 (OSPFv3), as defined in RFC 2740 and expanded in RFC 5340, is a modification of OSPFv2 allowing IPv6 support.
The primary purpose of OSPFv3 is to develop a routing protocol independent of any specific network layer. The internal routing information of OSPFv3 has been redesigned to serve this purpose.
OSPFv3 and OSPFv2 differ as follows:
OSPFv3 is used in IPv6, while OSPFv2 is used in IPv4.
OSPFv3 does not insert IP-based data in the header of an IP packet or Link State Advertisement (LSA).
OSPFv3 uses protocol-independent information to execute crucial tasks that originally required the use of the data in the IP packet header, for example, to identify LSAs that advertise routing data.