Reassured by a relatively smooth test of IPv6 last week, some Web sites are choosing to keep servers available over the next-generation Internet technology.
And that's good news for an Internet that's bursting at the seams. The results of the test, called World IPv6 Day, may help encourage others to make the IPv6 upgrades.
In the test, a number of organizations broadcast that their servers were available on IPv6. That meant anybody who had an IPv6 Internet connection would get that version of the server rather than the usual IPv4 one.
"There is a great sense of relief that nothing bad happened," said Alain Durand, director of software engineering at network equipment Juniper Networks and a former IPv6 leader at Comcast and Sun Microsystems. "It's a big sense now that IPv6 is a mature technology that is ready to be deployed."
Internet Protocol version 6 solves what has become a significant limitation of the present IPv4 technology: a dearth of new IP addresses that devices need to exchange information over the Internet.
A small fraction of people--well under a tenth of a percent by several estimates--have network configuration problems that broke access to IPv6 sites on the Internet. But the test went well enough that IPv6 is here to stay.
For example, Google decided to keep the main YouTube.com site available over IPv6. And Facebook concluded it will continue to offer the IPv6 version of its Facebook developer site. And according to data from RIPE, the European organization that doles out IP addresses, others leaving their IPv6 services on at least for the time being include Sprint, Mozilla, and BBN Technologies.
Comcast, one of the largest U.S. Internet service providers, also participated in the test. It's been ramping up its own trials of IPv6 for customers, too: this month it began testing IPv6-based e-mail services and expanded IPv6 trials to San Francisco, Chicago, Philadelphia, and Miramar, Fla.
All of this activity indicates progress in dealing with the chicken-and-egg problem that has been IPv6. Ironing out the wrinkles is one thing, but providing content such as YouTube videos over IPv6 will provide an incentive for those who operate the Internet's networking equipment to start handling the IPv6 traffic properly and link up with each other.
"If all goes well...content can go to IPv6, and access can follow," said Lorenzo Colitti, Google's IPv6 guru, in a presentation about World IPv6 Day (PDF).
Why all this hassle?
IPv6 follows on from the present IPv4 technology, which provides only 4.3 billion IP addresses. That may sound like a lot of addresses, but it turns that people want to attach a lot of servers, PCs, phones, tablets, smart meters, automobiles, TVs, video game consoles, and home broadband network routers to the Internet. And until recently, moving to IPv6 was largely optional, so few bothered with IPv6's expense and difficulty.
Computer administrators could postpone IPv6 transitions because technology such as network address translation (NAT) let home broadband users, Internet service providers, and corporations share a single IPv4 address among multiple devices. There are drawbacks to NAT, but the approach lets people get more use out of IPv4.
But the IPv4 address shortage has become much more acute: at the central domain of the Internet, the last IPv4 addresses were allocated in February, and now the shortage is propagating down through the IPv4 sales channels.
IPv6 is vastly more spacious. It offers 340 undecillion IP addresses--or 340,282,366,920,938,463,463,374,607,431,768,211,456 if you're being precise--by using 128-bit IP addresses rather than IPv4's 32-bit addresses. Assigning unique IP addresses means devices that are second-class Internet citizens because they're hidden away behind NAT networking layers become full peers on the Net. That could increase security worries, but it also opens up new frontiers such as easier peer-to-peer communications.
In the distant future, everybody will have IPv6-capable computing devices that use an IPv6 Internet to get to IPv6 services. For now, though, it's a patchwork of IPv4 and IPv6 equipment.
To stitch things together, there are a number of approaches. "Dual-stack" equipment that can can communicate with either version of IP is the eventual solution, but in the meantime, there are various approaches such as Teredo, 6RD, 6to4, 6in4, and DS-lite to bridge the gap. Teredo is good for individuals testing the waters, but 6RD has larger-scale abilities that have been proven at French ISP Free.fr and seems to be gaining clout.
"6RD is an important IPv6 transition technology, as is plays a key role at the beginning of and during the IPv6 migration, said Daisy Sun, a product manager at IP testing company Ixia.
The transition will take years.
"We cannot abandon IPv4 right now," Durand said. "This is going to stay for the next five years, ten years, fifteen years--maybe even more."
IPv6 test results
Getting to IPv6 hasn't been easy. It's been a standard for more than a decade. A number of organizations with a vital interest in it, though, organized IPv6 Day to help try to break the logjam.
It began with major Web sites--Google, Yahoo, and Facebook--and content delivery networks Akamai and Limelight Networks. The first three house a huge amount of content people on the Net consume, and the latter two play an important role on the Net by helping to ensure data from a single Internet site is available globally. Organizing the day was the Internet Society, an advocacy and standards group.
Participation ballooned to include more than 1,000 participants--a tiny fraction of the companies, schools, governments, individuals, and others on the Net, but a strong turnout nonetheless. To try to smooth out difficulties some people might have, many directed Internet users in advance to an IPv6 readiness test site.
So, for 24 hours on June 8, many turned on IPv6 services. Some had offered IPv6 services before, but only on an IPv6-specific domain such as ipv6.google.com. With test, google.com itself became available over IPv6.
"World IPv6 Day turned out to be everything we expected. For most of the end users of the Internet it was a non-event, which is what we were hoping for. At the same time it was a good learning experience," said John Curran, chief executive of ARIN--the American Registry for Internet Numbers that allocates IP addresses.
He expects that will help encourage others to move to IPv6.
"A lot of the organizations that might have had concerns about turning on IPv6--they can now do that on their own schedule. It removes a bit of uncertainty they had about whether they'd be risking their business," Curran said. "If you look at top sites on the Internet, we're all turning on IPv6, and the Internet did just fine. We can deploy IPv6 in parallel in safety."
NTT America, which offers IPv6 services, had another important and reassuring data point for IT administrators: "The event did not result in an increase in customer support load," said Shawn Morris, manager of IP development.
The company pushed hard to make the test real. "We worked with both our customers and peers to turn up as much IPv6 connectivity as possible to make the day as successful as we could. IPv6 traffic volume on our network nearly doubled as a result of the event," Morris said.
Fundamentally, Curran thinks the positive results of the test could be a more effective incentive than the doom-and-gloom warnings that arrived a few months ago with the IPv4 exhaustion at the high level.
"It's going to have a very significant effect over the coming months," he said of World IPv6 Day. "I think this event potentially was more significant because it doesn't talk about a problem, it talks about a solution."