This question was originally posted by @maxturpin, I’m not sure why it has changed ownership. However, I will answer the question here.
OSPFv3 has a different philosophy than OSPFv2 for IPv4. In IPv4, OSPF is enabled globally and the participating networks are added using the network command. OSPFv3 functions differently. You enable OSPF on the participating interface. in this way, you are indicating which subnets are participating (the subnet directly connected to the interface) and you are also indicating the area to which the interface belongs. This is more intuitive than the configuration method of OSPFv2 because OSPF configuration is inherently connected to interfaces. Both types of logic work, however, OSPFv3 seems a bit more elegant. It is also easier to implement since you don’t have to think about what subnets you will include, but what interfaces will participate.
I hope this has been helpful!
Laz