IPv6 leaders hailed Comcast's progress.

``It’s a positive step forward anytime a service provider deploys IPv6 in their network, but it is especially significant to have a company the size of Comcast, with their extensive broadband Internet customer base, make this commitment,’’ says Cody Christman, Director of Product Engineering at NTT America, which has been offering IPv6 transit services in the United States since 2001.

``Comcast’s move is a necessary step in providing home broadband Internet customers in the U.S. access to the IPv6 Internet,’’ Christman added. ``Hopefully, other broadband service providers will follow suit.’’

Comcast is taking a unique approach to promoting IPv6 in the United States, by developing IPv6-based services for its customers and encouraging Web sites to offer IPv6-enabled content.

Comcast’s strategy is ``to leverage IPv6 for the huge number of end-points on our network that are subscriber facing,’’ Brzozowski says. ``We have a vested interest in making sure that we not only plan to enable IPv6 connectivity but that we are working with the community to enable IPv6 content and services.’’

Until now, IPv6-enabled content has been rare. One of the only high-profile U.S. Web sites to support IPv6 is Google.

``The majority of Web sites still do not support IPv6,'' says Dave Siegel, vice president of IP services product management at Global Crossing, which was one of the first service providers to deploy native IPv6 on its infrastructure. But Siegel added that Comcast's move ``should increase awareness of the need to help build momentum for IPv6 overall.''

Brzozowski says it’s unreasonable to expect consumers or companies to migrate to IPv6 unless IPv6-enabled content is available.

IPv6-enabled content is ``scarce but growing,’’ Brzozowski said. ``We made sure that Netflix and Limelight had sufficient opportunity at NANOG to talk about their efforts to enable IPv6…They did it in about two months time.’’

Following the Comcast IPv6 demonstration, Limelight Networks said it is one of the first content delivery networks to offer commercial IPv6 services.

Similarly, Netflix is now offering its members the ability to manage their rental queues and stream media by visiting www.ipv6.netflix.com.

The Planet, which hosts more than 15 million Web sites, has been offering IPv6 functionality for more than a year.

Comcast wouldn’t comment on when its own Web content —including sites operated by E!Entertainment Television, Style Network and the Philadelphia Flyers hockey team--would be IPv6-enabled.

``We’re working on this internally, but I can’t elaborate on when,’’ Brzozowski said. ``Rest assured that better than anybody else, we understand that content and connectivity go hand-in-hand.’’