A 6in4 address ends in an IPv4 address so it doesn&#x27;t actually add any IP space: A 6in4 host can&#x27;t allocate additional IPv6 addresses that are routed over IPv4.<p>An IPv4+ address reserves 32 bits for the network address, and has (say) a 64 bit host address after it.<p>This means that IPv4+ hosts can be allocated by anyone with an IPv4 address.