Explanation/Reference: Explanation: 6to4 tunnel is a technique which relies on reserved address space 2002::/16 (you must remember this range). These tunnels determine the appropriate destination address by combining the IPv6 prefix with the globally unique destination 6to4 border router's IPv4 address, beginning with the 2002::/16 prefix, in this format: 2002:border-router-IPv4-address::/48 Because the border-router-IPv4-address is added, we will have a /48 prefix (we all know an IPv4 address consists of 32 bits). An example of a 6to4 address with the border-router-IPv4-address of 192.168.1.2 is 2002:C0A8:01:02::/48.