While U.S. Internet service providers probably have about one year's supply of IPv4 addresses left, Asian and European ISPs are already activating users with IPv6 connections -- so content owners worldwide should adopt the next-generation protocol as quickly as possible, according to a top Internet official.
"The Internet is slowly beginning to convert [to IPv6]," said John Curran, president and CEO of the American Registry for Internet Numbers.
In February 2011, the Internet's central pool of about 4.3 billion IPv4 addresses was depleted -- with the last blocks doled out to the five regional Internet registries. ARIN is the entity responsible for allocating IP address space to ISPs and other organizations in North America and parts of the Caribbean. The four others are APNIC for the Asia-Pacific region; RIPE for Europe, the Middle East and Central Asia; AfriNIC for Africa; and LACNIC for Latin America.
Since February, APNIC ran out of its remaining IPv4 space almost immediately, necessitating the move to IPv6, an address scheme that provides an astronomically large number of unique IP addresses. RIPE is about to run out of IPv4 addresses as well, "probably by CES if I'm correct," Curran said.
IPv4 and IPv6 are not compatible, so without some kind of translation layer, websites and other Internet servers hosted on IPv4 are invisible to users with IPv6-only end devices (and vice versa). ISPs are expected to provide large-scale translation for IPv6-only customers to reach existing Internet sites, but "we don't really know how well that will work," Curran said. That means content publishers should provide IPv6-hosted versions of their websites to ensure users can reliably access them.
"The fact is, it's one global Internet," Curran said. "If you're not IPv6-reachable, we don't really know what's going to happen... you probably won't be able to reach customers."
ARIN, which serves 3,000 members in the region, expects its remaining IPv4 blocks to last about 12 to 18 months but "it's very hard to forecast," Curran said. "If all the household names came in tomorrow, I might be out the next day."
Curran pointed to Comcast's recent IPv6 launch as leading initial U.S. deployments among ISPs, and said other large providers are readying plans. "We're seeing a lot of growth, but it's not going to be visible until we get to [IPv4] run-out in the next year or year and a half," he said.
This fall Comcast began activating IPv6-connected customers on its live commercial networks. The MSO now has more than 1,000 customers connected via IPv6 in several markets, including San Francisco' East Bay area, Illinois, Florida, Pennsylvania and New Jersey. According to Comcast, it's the first large ISP in North America to start deploying IPv6.
Comcast currently provides a "dual-stack" implementation for customers that provides both IPv6 and IPv4 connectivity on end devices.
"This is a significant milestone not just inside our own company but also in the industry, particularly given the chicken-and-egg relationship between the availability of content and software that supports IPv6 and the deployment of IPv6 to end users," Jason Livingood, vice president of Internet systems in Comcast's Network and Operations group, wrote in a blog post last month.
As of July 2011, 54% of ISPs and organizations (such as universities) said they had deployed IPv6 on the Internet, while 19% are running it only on internal networks and 27% don't have any IPv6 presence, according to a survey sponsored by ARIN and the other regional Internet registries.
Of those providers and organizations running IPv6, 78% said IPv6 traffic was insignificant; 18% said it was negligible; and the remaining 4% said it was either the same as IPv4 or greater.
The not-for-profit Internet Society this summer sponsored World IPv6 Day, a 24-hour global test of the protocol that spanned June 7 and 8 in the U.S., aimed at promoting IPv6 adoption and discovering critical technical issues. Participants included Google, Facebook, Microsoft, AOL, Yahoo and Turner Broadcasting System. The Internet Society plans to hold another World IPv6 Day in 2012 but the date has yet to be determined, according to a spokeswoman for the group.