Comcast plans to announce its service for home gateway users later this month, but company officials released a few details about this service at the North American IPv6 Summit held here this week.
John Brzozowski, chief architect for IPv6 and distinguished engineer with Comcast, said IPv6 service was already available to home gateway users in two U.S. cities. The service is available for residential customers that use one of six home gateways, which are specific IPv6-enabled models from D-Link, Linksys and Netgear that are listed at this .
"When we launch this service in an area, we are instantly seeing IPv6 traffic among home networking users that have IPv6 turned on by default," Brzozowski said.
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Comcast is providing home networking users with what's called dual-stack service, which includes support for native IPv6 as well as the current version of the Internet Protocol, dubbed IPv4.
"With our customer home networking service, you take your home of some variety, plug it into the back of our cable modem, and now you have IPv6 in your home," Brzozowski explained. "On any device - your , your Mac, your tablet - you now have native dual-stack service to the Internet."
is a looming upgrade to IPv4, the Internet's main communications protocol.
IPv6 is needed because IPv4 is running out of addresses to connect new users and new devices to the Internet. IPv6 solves this problem with a vastly expanded address space, but it is not backwards-compatible with IPv4. So ISPs like Comcast have to upgrade their routing, edge, , and customer premises equipment (CPE) to support IPv6. The alternative is for carriers to translate between IPv4 and IPv6 addresses, which adds latency and cost to network operations.
Upgrading a network as large as Comcast's to support IPv6 is "non trivial," Brzozowski says.
Comcast has been working on its IPv6 deployment for seven years, starting with the ability to manage its own network devices using IPv6, then migrating the company's internal network to IPv6, and now deploying IPv6 to all of its residential customers in a seamless, non-disruptive manner.
Comcast says its entire network will support IPv6 by the end of 2012.
"What we're really talking about is enabling high-speed data," Brzozowski says. "We've made sure that everything we designed, developed and deployed could support IPv6 at scale. Everything had to be the same with IPv6 as with IPv4. We couldn't put IPv6 in our customers' hands that was below par."
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Comcast's IPv6 service for home networking users is the latest in a series of IPv6-related announcements that the company has made in the last five months.
In a somewhat controversial move, Comcast is giving each of its home networking users what's called a /64 block of IPv6 addresses, which represents more than 18 quintillion IPv6 addresses or . This is a massive amount of IP addresses for techies to ponder given how long they've functioned in the address-constrained mode of IPv4.
Brzozowski said Comcast has to give a /64 set of IPv6 addresses because that's the only size of IP address blocks that CPE supports today. He said Comcast will re-number its initial home gateway customers with shorter prefixes of IPv6 addresses once home gateway makers have compliant, interoperable products that support this feature.
"We have no intention of staying fixed on /64s," Brzozowski said. "Our goal is to get something out sooner rather than later, then we'll go back and incrementally introduce support for shorter prefixes. Maybe later this year we will be prepared to have Version 2 of our home networking service with shorter prefixes."
Until recently, home gateways have been a major stumbling block for ISPs like Comcast that are trying to deploy IPv6 because the devices lacked support for the new standard. Home gateways are mini-routers with firewall capabilities that consumers use to create networks in their homes, connecting PCs, tablets, TVs and gaming systems to the Internet.
"IPv6 home networking support is generally improving," Brzozowski says, pointing out that three months ago only one home gateway model sufficiently supported IPv6 and now there are six involved in Comcast's home networking service. "The upgrade of home networking equipment is still required. Some customers may require the purchase of new hardware or a software upgrade."
Added Lee Howard, director of network technology at Time Warner Cable: "Less than 1% of home gateways have IPv6. I can't rely on home gateways, instead I have to rely on the 15% of people that have no home gateway and plug directly into cable modems for my initial IPv6 deployment."
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Meanwhile, Comcast has enabled tens of thousands of customers across the country to use its original residential , which was for customers with standalone computers connected directly to cable modems. The standalone computer users that qualify for this service must run an operating system - such as 7, Windows 8 or OS X Lion - that enables IPv6 by default.
Comcast's nationwide launch of stand-alone computer support for IPv6 began last November, and all of these customers are receiving dual-stack support for both IPv6 and IPv4.
Comcast is working towards the goal of having 1% of its 18 million residential subscribers use IPv6 by June 6, 2012, as part of its commitment to . On , more than 1,000 leading Web sites including Facebook, Google and Bing as well as ISPs such as Comcast, Time Warner and AT&T have committed to turn IPv6 on and leave it on for good.
"We're not there yet, but we are tracking to reach 1% by June 6," Brzozowski said.
Brzozowski says once Comcast has completed its IPv6 roll-out, the company plans to offer innovative new services on its next-gen platform. "We're already looking at ways to do more advanced intelligent home networking and communications and simplification of in-home services," he said.
in Network World's LAN & WAN section.