Last September, Federal CIO Vivek Kundra issued a memo mandating that government agencies take aggressive steps to adopt IPv6. IPv6 is the next-generation Internet Protocol, which allows for a vastly increased address space: 340 undecillion (340 followed by 36 zeroes) as compared to 4.3 billion addresses for the existing protocol, IPv4. The memo stipulates that agencies are to make all public-facing Internet resources IPv6-accessible by September 30, 2012, and that all internal connectivity within agencies and sites must use IPv6 by September 30, 2014.  Kundra’s aggressiveness appeared to be well-placed, when, on February 3, 2011, the Internet Assigned Numbers Authority (IANA), allocated the very last chunks of IPv4 address space to the Regional Internet Registries (RIRs). This officially signaled the beginning of the end of IPv4.

It’s not about our addresses.  While many organizations, government agencies, universities, and companies feel that they have sufficient IPv4 address space so that they don’t need to implement IPv6, that’s not really the problem. The depletion of IPv4 addresses signals the advent of IPv6-only organizations and networks. New scientific research facilities, community organizations, and educational institutions around the world will soon find it much harder–and more expensive–to obtain IPv4 addresses. For these organizations, their only hope for having a presence on the Internet will be to make extensive–and possibly exclusive–use of IPv6.

Thus, even those who have abundant IPv4 resources may soon need to access IPv6-only resources.  Network staff need to be ready to act when IPv6-only users and collaborators elsewhere in the world need to access resources at their sites, or when their researchers request access to IPv6-only remote facilities.  This means that everyone needs to proceed in earnest with IPv6 adoption, so that the inevitable kinks can be worked out before IPv6 becomes a mission-critical requirement.

Many people wonder if Network Address Translation (NAT), which allows certain IPv4 addresses to be re-used throughout the Internet, can help stave off the need for IPv6. While this was a common argument in the 1990s and early 2000s, the acceleration of IPv4 depletion in the latter part of the last decade calls this assertion into question.  NAT technologies have been known to work–with some difficulty–on a small scale, but the kinds of large-scale NAT installations required to continue with an IPv4-only Internet are expensive and come with their own reliability and security issues.  Some, such as Lorenzo Colitti of Google, believe that large-scale NAT will make the Internet, as a whole, “slower and flakier.”

Currently, IPv6 is our best way forward when it comes to maintaining the reliability of the Internet.  Having adopted IPv6 many years ago, ESnet is well-positioned to provide help to others making the transition. But it’s important to get moving now.  The depletion of IANA IPv4 resources and the Federal mandate should provide good motivation.

–Michael Sinatra