IPv6 Crunch Time Nears

With the clock ticking, CableLabs now is holding weekly IPv6 phone conferences with cable-industry players.

Typically, representatives of some 35 MSOs are on each call, said Chris Donley, CableLabs’ project director/Network Protocols, speaking at a recent symposium on the industry’s next-generation broadband strategies. More than a hundred additional personnel get transcripts of those weekly calls.

The sense of urgency is palpable. “There’s a lot of work to be done, and it really has to be done this year,” Donley said, pointing out that while the American Registry for Internet Numbers (ARIN) still has a few months of breathing room, the Internet Assigned Numbers Authority (IANA) ran out of new addresses more than a month ago. The European and Asia-Pacific registries will follow ARIN, and then the rest of the world, with IPv4 addresses disappearing in about a year and perhaps sooner. Indeed, there only are five address blocks of 16 million addresses each left for IPv4 globally.

Comcast engineer and Chief Architect for IPv6 John Jason Brzozowski had harsh words for any MSO that isn’t getting ready for the move to IPv6. “Not deploying IPv6 implies that you’re going to have to do something else to grow your business,” he warns.

Adds Donley, after considering some 20 possible technical solutions, current work is centered on just three co-existence technologies that will allow IPv4 addresses to work while the transition to IPv6 takes place, a transition “envisioned as a very gradual migration.” In part, he said, that’s because of the need to replace all home networks that are IPv4, something that won’t happen quickly.

Meanwhile, on the network side of those three technologies that passed the CableLabs initial cut – NAT44, Dual Stack Lite and IPv6 Rapid Deployment (6RD) – the last technology is now seen as the best way to get to IPv6 quickly. Both NAT44 and Dual Stack Lite, Donley said, are turning out to have “significant limitations” that affect such things as peer-to-peer and IP video streaming. 6RD, meanwhile, supports IPv6 over IPv4-only networks. 6RD is an enhanced version of the technology 6to4, in which IPv6 packets are encapsulated in IPv4.

Not everyone agrees, however. Comcast began IPv6 work six years ago, and initial trials began in January 2010, in Littleton, Colo. To Comcast’s surprise, 7,000 users signed up for the trial, said Brzozowski. Trials are set to begin in three more unnamed states, with the start of production deployment of IPv6 set for some time in the second half of 2011 using native dual-stack technology.

Brzozowski also recommended against use of 6to4, although Comcast has been testing it. 6to4 still is basically tunneling, he said, which is inferior to native stacks. The entire Comcast network is IPv6-capable or -enabled, he added, without disclosing how much of the network actually is enabled so far.

And whether the industry is really ready for IPv6 should become clearer on June 8, declared “World IPv6 Day.” During that one day, Google, Facebook, Yahoo!, Akamai , Limelight Networks and others will offer their content over IPv6 for a 24-hour "test flight."

– Stuart Zipper