You must perform the following steps to enable Open Shortest Path First version 3 (OSPFv3) to function on an interface:
- Issue the ipv6 unicast-routing command in global configuration mode.
- Issue the ipv6 address command or the ipv6 enable command in interface configuration mode.
- Issue the ipv6 ospf processidarea areaid [instanceinstanceid] command in interface configuration mode.

The ipv6 unicast-routing command enables IPv6 unicast routing on the router. IPv6 unicast routing must be enabled globally on the router so that the router can forward IPv6 packets.
The ipv6 address command enables IPv6 on the interface and assigns an IPv6 address to the interface.
The ipv6 enable command enables IPv6 on an interface but does not assign an address to the interface.
The ipv6 ospf processid area areaid instance instanceid command enables OSPFv3 on the interface if the previous two steps have been completed. You can also issue the ospfv3 processid area areaid {ipv4 | ipv6} instance instanceid command to enable OSPFv3 on an interface for a particular address family. Address families allow OSPFv3 to support both IPv4 and IPv6, but only one address family can be enabled on an OSPFv3 instance. Unlike OSPF version 2 (OSPFv2), OSPFv3 allows multiple instances to be enabled on a link.

Issuing the ipv6 router ospf processid command or the router ospfv3 processid command creates an OSPFv3 routing process on the router, but neither command is required to enable OSPFv3 to function on an interface. Enabling OSPFv3 on an interface automatically creates an OSPFv3 routing process on the router, so neither the ipv6 router ospfprocessid command nor the router ospfv3 command is required unless you need to configure global OSPFv3 parameters.

You are not required to issue the network networkid wildcard mask area areaid command in router configuration mode. The network command in OSPFv2 is used to specify which networks should participate in OSPF. Because OSPFv3 is configured directly on the interface, the network command is no longer necessary and is therefore unavailable in OSPFv3.