Currently, our Comcast High-Speed Internet Service (CHSI) uses Internet Protocol version 4 (IPv4) addresses, such as The supply of IPv4 addresses is limited and will eventually be exhausted. As a result, in order for the Internet to continue to grow, ISPs and other organizations need to transition to IP version 6 (IPv6) addresses, which take a very different form, such as 2001:0db8:4545:3:200:f8ff:fe21:67cf.

Comcast has been a leader in IPv6 development for over 5 years. Our leadership continues today with a plan to conduct real, production-network trials of IPv6 technology this year. The transition from IPv4 addresses to IPv6 addresses is a necessity, as the available pool of IPv4 addresses will at some point be exhausted for all Internet users.

Many experts believe that this transition could be disruptive for Internet users, so the trials we plan to conduct in 2010 will help us identify and solve any areas of difficulty involved in the transition to IPv6. We’ll also use this trial to determine what approach will be the easiest and most seamless for our customers. Comcast will continue to share what we learn with the Internet community, particularly with the IETF, for the benefit of other users of the Internet.

We anticipate conducting several technical trials, with the first trial set to start within the next couple of months. Customers who would like to participate in these IPv6 trials can express their interest using the online form on the new Comcast IPv6 Information Center website at

As the Internet Society (ISOC) said in a recent paper, "The Internet Society does not believe that stakeholders have the luxury of taking a wait and see approach or indulging in circular ‘who goes first’ discussions. IPv4 depletion is imminent and the time for moving to IPv6 is nigh. The Internet Society appreciates that many players – such as network operators, hardware manufacturers, handset manufacturers – have made great strides in engaging on this important issue, but, as most would agree, much more needs to be done by all stakeholders. Much greater preparedness for IPv6 – across networks, hardware, and applications is needed. Business continuity and opportunity, and therefore national competitiveness, depend upon it."

We hope that these trials will encourage other stakeholders to make plans to continue, or to begin, work on IPv6 in 2010 so that all stakeholders do their part in ensuring the future of the Internet is as bright and innovative as it has been in the past.