IPv6 - Blocks, Slashes and Big Numbers

June 23, 2011

IPv4 addresses are 32-bit while IPv6 addresses are 128-bit. Customers can get a /64 allocation of IPv6 addresses provisioned to a single SoftLayer server. A /64 block of IPv6 addresses contains 18,446,744,073,709,551,616 distinct addresses. The entire IPv4 address space is 4,294,967,296 distinct addresses.

It's easy to get lost in a sea of numbers when you start talking about IPv4 and IPv6 address space. With the exhaustion of IPv4 address space and the big push toward IPv6, everyone's talking about address blocks, usage justification and dual stack compatibility, but all of those conversations presuppose a certain understanding of why IP addresses are the way they are. Someone can say, "The IPv6 pool is exponentially larger than the IPv4 pool," but that statement needs a little context when you hear that providers like SoftLayer are provisioning a free /64 IPv6 allocation of 18,446,744,073,709,551,616 addresses to a single server. If the entire IPv4 pool on the Internet is 4,294,967,296 addresses and we're giving away that many IPv6 addresses to a single server, a simple question logically follows:

MattCodes

Are the Internet authorities being irresponsible when they're allowing such huge numbers of IPv6 addresses to be assigned to individual servers without a demonstrated need for that many addresses? Will this "wastefulness" lead to another IP address pool depletion in our lifetime? These questions are completely legitimate, and they're much easier to explain in a visualized format than they are if we answered them line-by-line in text:

The video duration might seem intimidating, especially if you consider that all 15 minutes are spent talking about IP addresses (Woohoo!), but there's a lot of information, and we did our best to break it down to simple pieces that logically follow each other to help you get the full picture of the world of IP addresses. We explain what CIDR Slash (/) Notation (where you see IP address blocks written as "192.0.2.0/24"), and we offer a simple trick to calculate the number of distinct addresses available in a given IPv4 block. There's a fair amount of witty (and not-witty) banter and at least one use of the word "ridonkulous," so if you enjoyed the DC Construction video commentary, you'll get a kick out of this one too.

Toward the end of the video, we speak directly to why SoftLayer is able to give a /64 of IPv6 addresses to every server and what that means for the future of the IPv6 space.

Fun Fact: SoftLayer IP Address Space*

  • IPv4: 872,448 Addresses
  • IPv6 (/32): 79,228,162,514,264,337,593,543,950,336 Addresses

*Does not include IP space assigned to The Planet

Did the video help you wrap your mind around the differences between IPv4 and IPv6? Do you have any more questions about the differences between the two or how SoftLayer is approaching them?

-@khazard

Categories: