OSPFv3 cannot support IPv4 at the time of this writing. To route both IPv4 and IPv6 with OSPF, you must run both OSPFv2 and OSPFv3.
2
Multiple instance per link means that there can be separate adjacencies among different routers all connected to the same broadcast link, so that different OSPFv3 routing domains can use the same shared link without interfering with or having knowledge of each other. The Instance ID field in the OSPFv3 header makes this possible.
3
OSPFv3 packets are authenticated using the built-in IPv6 authentication (by means of the IPv6 Authentication extension header). OSPFv3 does not have its own authentication mechanism as OSPFv2 does.
4
The OSPFv3 Next Header number is the same as the OSPFv2 Protocol Number, 89.
5
OSPFv3 uses the reserved multicast addresses FF02::5 (AllSPFRouters) and FF02::6 (AllDRouters).
6
No. OSPFv3 uses the same five message types as OSPFv2.
7
The first bit is the U bit, specifying how the receiving router should treat the LSA if its type is unknown. The second and third bits are the S bits, indicating the flooding scope of the LSA.
8
OSPFv3 supports a link-local flooding scope that is not supported by OSPFv2. The Link LSA uses this flooding scope.
9
OSPFv3 Router and Network LSAs do not advertise prefixes, as OSPFv2 Router and Network LSAs do.
10
The Intra-Area Prefix LSA carries IPv6 prefixes connected to the originating router.
11
The Link LSA carries information that is only significant between two directly connected neighbors.
