IPv6 addresses

IPv6 is the newer version of the Internet Protocol. It was introduced because IPv4 does not provide enough addresses for all the devices that need to connect to networks.

Why IPv6 is needed

An IPv4 address is 32 bits long, so there are 2 to the power 32 possible IPv4 addresses. That number cannot cover every piece of equipment that now needs a connection, especially as people now connect phones, tablets, games consoles and smart devices as well as computers. An IPv6 address is 128 bits long, so there are 2 to the power 128 possible addresses. This is vastly more than IPv4, giving enough address space for the foreseeable future.

The format of an IPv6 address

An IPv6 address is made of eight groups, with 16 bits in every group. A group is shown as four hexadecimal digits, and colons separate the groups. Hexadecimal uses digits 0 to 9 and letters A to F, and each hexadecimal digit represents 4 bits. So four digits make 16 bits, and eight groups make 128 bits.

For example, a valid IPv6 address is 3f2a:9c41:00b7:5d18:e6a3:1174:8f02:bb59. It has eight groups. Each group has four hexadecimal digits. In total there are 8 × 4 = 32 hexadecimal digits, and 32 × 4 = 128 bits.

Telling IPv4, IPv6 and MAC addresses apart