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New Entries for the Net’s Address Book

9/08/2006 8:00 PM Eastern

It could claim the record for the Internet technology with the longest adoption curve.

Developed some 15 years ago — even as the World Wide Web was being knit together — Internet Protocol version 6, or IPv6, is an update to Internet Protocol version 4, the communications framework that now governs the Web.

IPv6 has been quietly at work on the world’s major Internet backbones for several years, but now with its inclusion within the new Data Over Cable Service Interface Specification 3.0 scheme and Microsoft Corp.’s new computer operating system, due out some time next year, it may finally be ready for its primetime consumer debut.


While slow in coming, IPv6 offers several key upgrades to its rapidly aging predecessor, and the one that’s getting the most attention is the much-needed expansion in the number of IP addresses it allows.

IP addresses are assigned to computers and other devices that are hooked up to the Internet, so the network can efficiently deliver data. As with other Internet providers, cable operators own a pool of IP addresses that were doled out by an oversight body, the Internet Assigned Numbers Authority.

But with more devices adding Internet-link capabilities — ranging from computers to phones and mobile devices — the existing IP system is starting to run out of available addresses to assign.

Enter IPv6. It offers a huge increase in the number of IP addresses available, by expanding the number of bits in each data packet’s identification header from 32 to 128. More bits means more possible combinations, and with IPv6, the jump is massive.

While the current IPv4 system can supply 4.3 billion addresses, IPv6 allows a whopping 3.4×1038 IP addresses, in scientific shorthand. That’s 3.4 with 38 zeros after it, instead of 4.3 with nine zeroes after it.

IPv6 also simplifies how IP addresses are assigned. Under IPv4, devices have to configure to the network each time they are activated, and both sender and receiver devices have to know that the other has a particular address. That gets fairly difficult when the devices such as Internet-capable phones move around, tapping multiple cellular networks.


With IPv6, devices automatically configure to their own addresses no matter which network they are linked to, “so it’s really hard to screw up IPv6,” said John Chapman, a Cisco Systems Inc. engineer who has worked extensively with IPv6.

IPv6 also better defines security measures to protect devices from hacker attacks, and it eliminates public and private IP-address silos that separate devices, including cable modems and cellular phones, from computers.

Cisco has been a major player in developing IPv6, helping to author the features used in DOCSIS 3.0. Like most other major providers of core Internet routers and switches, it has already built the new version of IP into its product lines.

On the consumer device side, a key driver for IPv6 adoption will be Microsoft’s long-awaited Vista operating system, which for the first time uses IPv6 as the preferred Internet Protocol scheme to direct how the home computer connects and transfers data across the Web.

Meanwhile, the DOCSIS 3.0 specification recently released by CableLabs Inc. includes support for IPv6 for the first time — an acknowledgment that cable operators will need to have the tools to eventually transition to IPv6.

“We put a stake in the ground saying, 'We’re probably not going to do a DOCSIS 4.0 for some time, and we’d better get this in place or otherwise it will be difficult for cable operators to make that transition,’ ” said Ralph Brown, chief technology officer at CableLabs. “So we’re doing it as part of DOCSIS 3.0 to address our members’ concern about IP address exhaustion and to get them ready for that transition.”


But despite all of the improvements IPv6 offers, not all cable operators appear enthusiastic about transitioning to this updated Web communications scheme. That includes Cox Communications Inc., which is keeping an eye on the technology but hasn’t moved toward adopting it, according to Randy Kinsey, Cox’s director of IP engineering.

To start with, doing so would require a lot of education and planning.

“It’s more than just each of your devices supporting it. Every component of everything that we do would have to be touched and updated,” Kinsey said. “And then you are going to go through the whole process of relearning everything — the changes in the way that the protocol behaves and the security aspects. It just goes on and on and on, and there is a huge learning curve there.”

Another reason Cox isn’t rushing toward IPv6 is that its pool of IP addresses is, so far, not in danger of running out, Kinsey said. Like other operators, it is assigned public IP addresses for devices that need to be identified for Web routing — such as home computers — as well as private IP addresses for devices including cable modems that are only identifiable within the operator’s own network. The latter is essentially an internal routing address that can’t be seen by the outside world.

So far, Cox’s bank of public Internet addresses is ample enough. For the more limited number of private IP addresses, the cable operator can duplicate and use the same addresses in each of its markets, as long as the networks for those markets don’t connect directly, Kinsey said.

Cox may be facing no immediate problems, but larger cable operators and Internet-service providers may soon stretch the limits of their address pools, according to Brown. Estimates vary, and “different people have different positions about how quickly that is going to be exhausted — whether it is in the next two years or the next 10 years,” he said.

There are also questions whether IPv6’s strategy of providing every device with a definable public address is itself a risk. The worry lies in the fact that IPv6 so far hasn’t faced attack from wily Internet hackers, Cox’s Kinsey noted.

“Everyone talks about the security components of IPv6, but there are a lot of people that believe it will be less secure during the initial rollout until we understand it,” he said. “So once we get it out there and people really start beating on it, then we have to learn everything about it all over again — all of the things that we learn very well about IPv4 we have to learn all over again, and during that time, I agree we probably will be less secure, to a degree.”


Despite such concerns, it appears adoption of IPv6 is gaining some momentum. Many government agencies and corporations are starting to mandate IPv6 capabilities in the Internet systems they buy, “with the anticipation that over time they are going to transition to IPv6,” Brown said.

With core routers already capable of handling IPv6, the next step will be to offer IPv6 driven services to the home, and in the U.S. market that will start with setting up the basic device provisioning and management systems, Cisco’s Chapman said.

Lab trials are already under way to test these systems, and that will lead to field trials in early 2007. Limited market trials will likely follow in late 2007, and the full deployment will begin in 2008, Chapman predicted.

For cable operators, the transition will focus on the cable modem termination units and the cable modems, and that is where DOCSIS 3.0 comes into play.

But as with other upgrade processes, operators will likely have a mix of older modems and new DOCSIS 3.0 modems. That will mean putting routers and other network devices in a dual IPv4 and IPv6 mode, so they can talk to devices in both camps.

“So cable operators will have to operate what are called dual stack or dual mode networks, and they will be supporting both IPv4 and IPv6 on their networks for probably a fairly extended period of time,” Brown said, noting that could be as long as a decade. “So they will be basically running two networks in parallel.”

The upshot is that while there is some question as to timing, it appears IPv6 eventually will assume command of Internet communications.

“I’m sure it’s not going to be without its challenges, but the rewards outweigh the challenges,” Chapman said. “It kind of boils down to an operations exercise — I think the technology guys are done, and now it’s just operations.”