The figure shows the differences between OSPFv2 and OSPFv3:
- Advertises - OSPFv2 advertises IPv4 routes, whereas OSPFv3 advertises routes for IPv6.
- Source address - OSPFv2 messages are sourced from the IPv4 address of the exit interface. In OSPFv3, OSPF messages are sourced using the link-local address of the exit interface.
- All OSPF router multicast addresses - OSPFv2 uses 224.0.0.5; whereas, OSPFv3 uses FF02::5.
- DR/BDR multicast address - OSPFv2 uses 224.0.0.6; whereas, OSPFv3 uses FF02::6.
- Advertise networks - OSPFv2 advertises networks using the network router configuration command; whereas, OSPFv3 uses the ipv6 ospf process-id area area-id interface configuration command.
- IP unicast routing - Enabled, by default, in IPv4; whereas, the ipv6 unicast-routing global configuration command must be configured.
- Authentication - OSPFv2 uses either plaintext authentication or MD5 authentication. OSPFv3 uses IPv6 authentication.