Published on November 16, 2008

What IPV6 128 bits address means

The current protocol that the Internet is based on is called IPv4 (Internet protocol version four) and has an address space of 32 bits, or 2³², or 4 294 967 296 possible addresses that can be assigned to devices that are part of the Internet.

That may seem like a lot, but due to the rapid expansion of the Internet (computers, devices like routers and switches) and also of the number of networks that make up the Internet (a network of networks), this is increasingly scarce.

IPv6 is coming to the rescue, with an address space of 128 bits. That is no more and no less than 340 282 366 920 938 463 463 374 607 431 768 211 456 addresses (2¹²⁸). To get an idea how big this number is, consider that:

• If the IPv6 addresses would be assigned uniformly over the entire volume of the Earth, every cubic centimeter would get 314 billion addresses. This is 73 IPv4 Internets per cubic centimeter.

• If each atom from a piece of iron would get one IP address, that piece of iron would be a cube 1.588 kilometers each side, or a little less than a mile.

• Considering that the diameter of the Universe is 93 billion light years, or 8.80 ×10²⁶ meters, spreading uniformly all the IPv6 addresses over this distance would result in 386,684,508 addresses per millimeter. You would need a very powerful microscope to see the space allocated for one.

• Currently there is estimated that there are between 2,000,000 to 200,000,000 insects on Earth for every human being. That would be up to 1.36 million trillion insects in total. If this number would grow to a trillion trillion, then each insect could get 79 000 IPv4 Internets.

Sounds like an overkill? I bet it does!