We have some more exciting IPv6 news to share today. Comcast Labs and Internet Systems Consortium (ISC) just released free open source software that may help facilitate the industry’s transition to IPv6, the global numbering system essential to the continued growth of the Internet.

The Address Family Transition Router software (AFTR, which is pronounced "After" as in "after IPv4") is part of a technology that could enable users to access IPv4 content from their legacy IPv4 devices & applications over an IPv6 network. As you may have read previously Comcast recently began a series of real network trials of IPv6 technology.

The common thinking in terms of IPv6 transition has long been that the adoption of IPv6 will be based on the dual stack model. That is, all Internet devices will be bilingual and "speak" both IPv4 (which is the current "language" of the Internet) and IPv6. The idea was that most devices would be converted before the Internet ran out of IPv4 addresses. However, according to the American Registry of Internet Numbers (ARIN), exhaustion of the pool of IPv4 addresses will occur sometime between 2011 and 2012.

Today, most of the Internet is still IPv4 only. As IPv6 and IPv4 cannot communicate directly with each other, a direct cut over to IPv6 is not a realistic option when the pool of unallocated IPv4 addresses runs out. In the meantime, transition technologies may be needed to enable IPv4 and IPv6 to continue to work.

Comcast and ISC have partnered on this new technology to help IPv4 and IPv6 work together. Version 1.01 of the AFTR code is available today for free to any company or anyone that would like to test or build upon the software. You can download the source code at https://www.isc.org/software/aftr. It is the culmination of almost five years of joint IPv6 research and development by Comcast and ISC.