"Networks are starting to move to IPv6. Now it's time for content owners and content producers to step up their efforts and start moving to IPv6. The government announcement was key and shows that they are sensing [this trend] as well. It was a welcome announcement," Livingood says.
Comcast is testing three IPv6 transition mechanisms in its ongoing trial:* Dual-stack, which involves supporting native IPv4 and IPv6 traffic running side-by-side.* 6rd, a technique developed by French ISP Free that allows for rapid deployment of IPv6 by tunneling IPv6 traffic over IPv4 addresses.* Dual-Stack Lite, an approach developed by Comcast that uses network address translation to share one IPv4 address among many customers.
What Comcast has learned so far from its IPv6 trial is that it's better to adopt native dual stack than to use translation mechanisms such as 6rd or Dual-Stack Lite.
"The best option for us and others is native dual stack," Livingood says. "Not going through a middle box means IPv6 should be faster, less costly and less difficult to troubleshoot."
One key issue for ISPs is upgrading the home gateways that residential customers use to access the Internet to support IPv6.Comcast officials said they will announce on Friday that they are providing software to the OpenWrt community, which develops Linux-based software for residential gateways from Linksys, Netgear and others. The Comcast-developed software will allow home gateway devices to support 6rd and Dual-Stack Lite.
"The software will help users that have only IPv4 addresses to tunnel over IPv6, and it will help those who only have IPv6 addresses and want to tunnel over IPv4," Livingood explains. "We will be posting the software on SourceForge ...The community can benefit from it by directly using the software or studying how we've done it."
This represents the second time that Comcast has shared open source code with the Internet engineering community that was developed during its IPv6 trial. In March, Comcast and ISC released another IPv6 transition tool called Address Family Transition Router.
Next up for Comcast is starting its DOCSIS test.
"The DOCSIS trial hasn't kicked off as fast as we would have liked, but we're still fine and we can still manage in the timeframe we have left," Livingood says, adding that "we will have our network ready by 2012."
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