IPv6 – 6 over 4 Tunneling
6-over-4 tunnels are usually used in single organisations. It is also an automatic tunnelling technique but solves problems in different ways. It assumes that the IPv4 infrastructure is a single IPv6 subnet.
6-over-4 addresses are mapped to IPv4 multicast addresses, this stateless autoconfiguration. This tunnelling technique has not been largely deployed since the use of IPv4 multicasting is not widely used in today’s internetworking. 6to4 addresses are a valid prefix for the lower 64 bits in an IPv6 unicast address used for the identifier. This method of tunnelling is depreciated in favour of other techniques due to it only working with multicast IPv4 networks.
