Comcast to Participate in World IPv6 Day

Comcast and the Internet Society today announced that Comcast will participate in World IPv6 Day on June 8, 2011. We anticipate having our IPv6 trial users participate in this event, which will give them the opportunity to access many more sites natively over IPv6. In addition, we plan to have more of our websites available over IPv6 (the current list of IPv6-ready sites is here).

Comcast's First IPv6 Native Dual Stack Over DOCSIS Users Activated!

As noted here in our blog, we are very excited to announce that Comcast has successfully activated our first group of trial users for IPv6 Native Dual Stack operation. These are the first Native Dual-Stack users activated in a production DOCSIS network in North America. Leveraging our state-of-the-art, production DOCSIS 3.0 network, these users can now access content and services natively over both IPv6 and IPv4. This means users do not need to use any IPv6 or IPv4 tunneling, translating, or NAT solutions; they can access IPv6 and IPv4 directly at high-speed, in an unencumbered fashion. This is a tremendous milestone for Comcast, cable operators, and the Internet community at large, and it is a critical milestone in our many years of work to prepare IPv6 to work seamlessly in a residential broadband Internet network. Each user has been delegated a /64 block of approximately 18,446,744,073,709,551,616 (18 quintillion) unique IPv6 addresses. We anticipate expanding our IPv6 Native Dual Stack trial in Colorado and in other areas in the coming weeks and months. Stay tuned here for further updates.

Keeping Track of Website Native Dual Stack Readiness

In 2011, we anticipate working to bring many of our websites to support native dual stack, so that they are accessible via IPv6. As a result, we'll be updating a list of sites that are IPv6-accessible here. That page will keep track of the mainstream sites that support IPv6, as opposed to specialized ones intended for testing.

Comcast Makes Several Presentations at IETF 79

One of the goals of our trials was to take the time to share our experiences with others in the Internet community. We have been doing so on a regular basis and last week a number of people from our IPv6 team participated in the 79th meeting of the IETF. At that meeting, team members made presentations at the Technical Plenary on our IPv6 experiences, in the Softwires Working Group on our Dual-Stack Lite experiences, and in the DNS Operations Working Group, IPv6 Operations Working Group, and the Internet Area Working Group on IPv6 AAAA DNS Whitelisting.

6to4 and 6RD Configuration Directions Posted

If you are on the Comcast network, you currently have been issued one or more IPv4 addresses. So if you'd like to try IPv6 you will need to tunnel IPv6 over IPv4, using a transition technology like 6to4 or 6RD. If you wish to try 6RD out, you can see the 6RD configuration instructions here. And if you wish to try 6to4 out, you can see the 6to4 configuration instructions here. Please note that in both cases, you will need to have a home gateway device with software that supports 6RD or 6to4, though if you have a compatible device you can use open source software we've released (see below).

Comcast Donates Additional IPv6 Open Source Software

As noted here in our blog, Comcast has now released additional free open source software under GPLv2 that may help facilitate the industry's and end users' transition to IPv6. We are releasing home gateway device (a.k.a. home router) software, which you can find here on SourceForge. Configuration directions are available here. This open source implementation was developed in conjunction with Xavient Information Systems, using the OpenWrt platform.

While it is very important that home gateway devices to support native IPv6, particularly native dual-stack (IPv4 and IPv6 simultaneously), devices may still need to handle situations where tunnel-based IPv6 transition technology would be used. Thus, these OpenWrt software extensions support cases where either IPv6 is tunneled over IPv4 using 6RD, or IPv4 is tunneled over IPv6 using Dual-Stack Lite (DS-Lite). In fact, this home gateway device software is one of two implementations used in Comcast's 6RD trial.

When this software uses 6RD, it tunnels to an 6RD Border Relay (6RD-BR). When this software uses DS-Lite, it tunnels to an Address Family Transition Router (AFTR), therefore communicating with AFTR software such as that which has been jointly developed with ISC. This figure shows where this software can assist, in the lifecycle of the IPv6 transition (click here for a larger version):

Comcast Participates in Two IPv6 Workshops This Week

This is a busy week for IPv6 in North America. On Monday and Tuesday in New York City, some members of our IPv6 team participated in an IPv6 workshop organized by CableLabs, the NCTA, and the SCTE. In addition, on Tuesday, we participated in this workshop organized by the NTIA in Washington, D.C.

6to4 Relays Activated

As we started our IPv6 trials, we began to observe an increase in 6to4 relay traffic. 6to4 is a transition mechanism built into some operating systems and home gateways. While it is not a transition technology that Comcast planned to invest in due to limitations related to performance, we did observe poor performance when 6to4 was used by our customers. In many cases, these customers were not even aware that 6to4 was enabled by default or that their device or operating system was attempting to use 6to4 to communicate with IPv6 resources on the Internet.

In most cases, we observed that 6to4-enabled operating systems and devices were attempting to use a 6to4 relay infrastructure hosted by a midwestern university. In order to improve the Internet experience for Comcast customers who are using 6to4, whether knowingly or not, we have decided to operate 6to4 relays on a temporary, trial basis.

Comcast has decided to deploy 6to4 relays in five locations around our network to improve performance and predictability, as compared to operating relays from a single location. These 6to4 relays are available via the standard 6to4 Anycast IP address, according to RFC 3068, which is Devices attempting to use 6to4 within our network should automatically discover and utilize these new 6to4 relays, without end user intervention or configuration.

The first pair of these relays was activated today. We plan to activate the remaining three within the next seven to ten days. We plan to monitor the performance of the 6to4 relays, to measure any beneficial effects resulting from adding these elements to our network. As our IPv6 trials evolve and we develop our plans for 2011 and beyond, we will assess our plans to support 6to4 moving forward.