Waiting too much longer to transition is a path toward guaranteed disaster.

Are you willing to run out of Internet addresses for new customers? No? Then that must mean you’re already in the process of reconfiguring your network to support IPv6.

Are you willing to run out of Internet addresses for new customers?You’re not? Well, you’re not alone. You’ve still got some time to start. And there’s help available from CableLabs and the SCTE if you choose to avail yourself of it. But if you drag your feet much longer, you will be on a path toward service failure.

Chris Busch, Incognito’s vice president of broadband technologies, summarized the situation: “React now, or overreact in a year.” He said companies in Europe and Asia are already moving toward IPv6, but activity in the U.S. has lagged, with a few exceptions, including the biggest MSOs.

So far, few other U.S. operators seem to be doing anything at all to prepare, Busch opined. “Maybe it’s, ‘Let’s see what Comcast does, and we’ll do that.’”

While many communications service providers have allocations of IPv4 numbers they hold in reserve to assign to future broadband customers, only 10 percent of all unallocated IPv4 addresses were left as of last January, according to the Number Resource Organization (NRO).

Given the current rate of address consumption, expect IPv4 address space to be fully depleted in about 18 months, give or take a few weeks – sometime in the third quarter of 2011.

Getting new allocations from NRO members – the companies that dole out addresses – used to be a pro forma process, but some CSPs that are close to exhausting their reserves of IPv4 addresses are reporting that getting new allocations now requires detailed justification.

Merely having an adequate supply of IPv4 addresses is only half the issue. The other half is that IPv6 addresses are already coming into use, and in order to enable your customers to start connecting to whoever or whatever has an IPv6 address, you’re going to have to reconfigure your network to support IPv6, while continuing to support IPv4.

IPv4 is not going away. Quite a bit of content on the Web will continue to be available only for IPv4. Many devices are not upgradeable, PlayStations and iPods among them.

Chris Donley, CableLabs’ project director, network protocols, at the SCTE Canadian Summit held in March, acknowledged there was some “delayed adoption” among some operators. That said, CableLabs reports that the industry has been “very active in planning for the IPv6 transition.” It’s just that only Comcast has been very open about its IPv6 transition plans.

CableLabs developed recommendations for conducting the transition as far back as 2006, but has been revising its plans to make sure that the spec meets all of their members’ needs.  

“Through the analysis, we are discovering that our original specifications do support MSO needs, and only needed minor adjustments to keep pace with recent developments in the IETF. It’s also not correct that MSOs have not been active with IPv6,” according to a CableLabs spokesman.

Donley said that the IETF is also working a set of new technologies that might make the transition easier. These are:

• Carrier Grade NAT (CGN): A means of sharing globally routable IPv4 addresses among multiple subscribers.

• NAT444: Leverages CGN to provide IPv4 services to subscribers. Requires a home gateway that can assign private IPv4 addresses to devices within the home.

• Dual-Stack Lite: This is another means of using a single public IPv4 address and sharing it across multiple subscribers.

• IPv6 Rapid Deployment (6RD): An extension of 6to4 (IPv6 to IPv4) tunneling that allows a service provider to designate a relay (as opposed to having a random relay chosen automatically). This makes it easier to deploy IPv6, Donley said.

• NAT64: A new means of allowing IPv6-only hosts to communicate with IPv4-only servers.

Donley said MSOs have determined that going to native IPv6 as the preferred option, and if that isn’t possible, then NAT444 is the second priority. Dual-Stack Lite is also supported, he said.

He said NAT64 is not ready and not needed yet. He had the same assessment of 6RD – it’s not needed in DOCSIS specifications, since DOCSIS 3.0 supports IPv6 natively. MSOs are willing to consider 6RD in areas where it is not feasible to deploy DOCSIS 3.0. Nonetheless, Comcast plans to trial the technology next month.

Wayne Allison, director of network technology and service lifecycle management at Rogers Communications, said Rogers has been working on the transition since 2008, but even so, there’s more to do, including evaluating all of the technologies outlined above.

Rogers has been running Dual-Stack in its core since last year. This year, the company’s goal is to get IPv6 on all DOCSIS 3.0 cable modems it has capable of supporting it. Rogers hopes to deal with all of the CPE behind those modems in 2011, Allison said, also speaking at the Canadian Summit.

He offered several warnings based on Rogers’ experience. Dual-Stack is harder than originally anticipated, he said. “You run into challenges with billing and provisioning.”

One unexpected problem was running out of private address space. “We thought that would be near infinite, but we’re actually running out,” he said.

Among U.S. MSOs, Comcast seems to be taking the lead on the subject. The company has been calling attention to the issue since 2005. Perhaps because of its enormous size relative to other cable companies, it quickly understood that the scope of the problem was huge and went well beyond just high-speed data (HSD).

Comcast several years ago calculated that with 20 million video customers, averaging 2.5 set-tops each, with two IP addresses per box, it had 100 million IPv4 installed addresses to manage even before it accounted for its data and VoIP customers.

But if Comcast is an accurate indicator, one might surmise it isn’t time to panic just yet. Comcast in January announced trials of IPv6 technology (6RD – despite CableLabs’ earlier assessment of the technology), and last month said it was shooting for June to commence.

Comcast plans to conduct several trials for both residential and commercial customers. Equipment to be tested includes CMTSs (Arris), routers (Cisco, Juniper) and gateways (Netgear, Linksys, Apple, Xavient).

So Comcast seems to be moving at a deliberate pace. And paraphrasing “The Hitchhiker’s Guide to the Galaxy,” Donley titled his presentation “No Need to Panic.”

One could surmise from one of Allison’s comments, however, that a bit of alarm might be merited. Keeping in mind Rogers began actively transitioning last year, he said. “We’re cutting it close – there may be a rush at the end to get it all done.”

It should be noted that the benefits of IPv6 go beyond vaster address space. The technology will also bring with it stateless auto-configuration, enhanced quality of service (QoS) and mobility support.

Meanwhile, the SCTE is offering a sevenweek online course on IPv6, called “IPv6: Impact on Cable Networks.” The course has been developed in partnership with Cisco and will provide an overview of the capabilities and roles of IPv6 and DOCSIS 3.0 in the cable network management process.

Marv Nelson, senior vice president of strategic initiatives for the SCTE, said: “We’ve created this course to provide the engineering community with the knowledge and skills that they’ll need to minimize the impact of the transition on cable operators’ businesses and to make the change as seamless as possible for customers.”

The course will begin May 24. The registration fee will be $250 for members and $325 for non-members. Registration and additional links to SCTE IPv6 resources are available on the SCTE’s website.

This article includes updates and corrections from the version in our print edition.