This memo defines two new Multi Topology Routing Identifiers (MT IDs), based on [I-D.ietf-ospf-mt-ospfv3] and two new Instance Identifiers (MI IDs), based on [I-D.ietf-ospf-af-alt], respectively, in OSPFv3. With these identifiers, an IPv4-Embedded IPv6 topology is maintained for both IPv6 unicast and multicast traffic. The purpose of running separate instances or topologies for IPv4- Embedded IPv6 traffic is to distinguish from the native IPv6 routing topology, and the topology that is used for routing IPv4-Embedded IPv6 datagrams only. Separate instances/topologies are also meant to prevent any overload of the native IPv6 routing tables by IPv4-Embedded IPv6 routes.