Comcast has begun pilot market deployment of IPv6 (Internet Protocol version 6), making the cable MSO the first tier 1 ISP in the U.S. to begin deploying the new internetworking standard and marking a “critical milestone” in the cable MSO’s six-year effort to do so.

“This is a significant milestone not just inside our own company but also in the industry, particularly given the chicken and egg relationship between the availability of content and software that supports IPv6 and the deployment of IPv6 to end users,” Jason Livingood, vice president of Internet Systems in Comcast’s Network and Operations group, wrote in a post on the ComcastVoices blog.

“In no small part this is due to our belief and firm commitment that there is value in long-term, strategic investment in technologies such as IPv6, and that this has benefits beyond our company and customers, across the Internet ecosystem.”

Comcast is taking a native, dual stack approach to the migration, supporting both IPv4 and IPv6 addressing, Livingood explained. Doing so “avoids breaking or slowing applications and maintains a better and faster broadband Internet experience” as compared to IPv6 tunneling through an IPv4 network or large scale NAT (Network Address Translation), he wrote.

The first phase of the pilot market deployment will involve directly connected CPE (customer premises equipment) where a single computer is connected to a cable modem. Subsequent phases later this year and next will involve supporting home gateway devices and variable length prefixes, Livingood elaborated.

Nonetheless, Comcast anticipates some technical bugs cropping up in the near term as it proceeds with its pilot market deployment program. Focusing on identifying and resolving such issues rapidly will enable Comcast to begin national deployment as soon as possible, according to Livingood.

Key technical details of Comcast’s IPv6 deployment plan are available in a post by Comcast Distinguished Engineer & Chief Architect for IPv6 by John Brzozowski.