The difficulties of adopting the next-generation Internet standard so far have outweighed its advantages, but one key part of the computing industry is showing signs of beginning the IPv6 transition in earnest: Internet service providers.
A total of 32 percent of ISPs offer IPv6 services to business customers today, according to a new European Commission-funded survey, said John Curran, chief executive of American Registry for Internet Numbers (ARIN), one of the world's five nonprofit Internet registry organizations that collectively hand out Internet addresses and keep track of which numeric addresses are connected to which servers on the Internet.
That percentage, though, is increasing.
"Sixty percent intend to have services within a year. That's a huge step up," Curran said. "Within two years, it is 80 percent."
He's baffled what the remaining 20 percent of ISPs will do, given that the Internet is expected to run out of the current limited stock of IPv4 addresses in about that same time frame, making ISPs left behind the virtual equivalent of a home-building contractor with no empty lots left on the street. According to Internet service company Hurricane Electric, which monitors the IPv6 transition, there are about 203 million IPv4 addresses left, enough to last less than nine months.
Hurricane Electric's estimate is reasonable, Curran said, though it's hard to predict exactly given the inconstant decline. The five Internet registry organizations pull unused IP addresses out of the pool as needed in so-called "/8" blocks of 16.7 million addresses at a time, then it takes some time for them to allocate them to ISPs and others. Fourteen of the original 256 /8 blocks are unused.
Even after the registry organizations have handed out their last IPv4 addresses, it'll probably be another six months before the ISPs exhaust their supply, Curran said.
The transition to IPv6 hasn't been easy, mostly because of a compatibility barrier that has pushed back the change until absolutely necessary. Those with an IPv4 connection to the Internet can't see IPv6 Web sites and vice versa, unless some gateway device is specifically set up to handle the chore.
For companies with Web sites or other Internet services, they must obtain new IPv6-based addresses for their servers and network connections to the outside world so they can handle IPv6 traffic. "If you've got a Web site, you should be looking at how to get it on IPv6 now," Curran said.
Some big companies have begun the transition; Google, a particularly fervent IPv6 advocate, has made YouTube and other services available on IPv6. Facebook also began its IPv6 transition, as has Comcast.
For ordinary consumers, they'll eventually have to upgrade DSL and cable modems, though because the IPv4 network will still work, they'll only miss out on Internet services available only over IPv6.
IPv4 (Internet Protocol version 4) catalogs Internet servers with 32-bit numbers, offering of 4.3 billion numeric addresses. That may sound like a lot until you realize only 6 percent are left unused today.
By comparison, IPv6's 128-bit address space offers a gargantuan number: 340,282,366,920,938,463,463,374,607,431,768,211,456 if you're keeping track.
That's enough to render unnecessary today's IPv4 stopgap measures, including network address translation (NAT) to let multiple devices share one IP address in something like the same way that an apartment building with one street address might have many subunits. IPv6's capacity also is vast enough to assign IP addresses to countless devices that don't merit them today--mobile phones, printers, cars, and the growing variety of other new devices in an increasingly network-aware world.
The EC-funded survey polled 1,500 companies, 58 percent of them ISPs, in 140 countries. The study also found that awareness of IPv6-related issues is strong, with 84 percent already possessing IPv6 addresses of their own or planning to request them.
The five regional Internet registries charge a fixed fee for allocating IP addresses, but that doesn't necessarily stay the same at Web hosting companies, ISPs, and others that sell the addresses to the actual customers.
"The demand curve goes from very low to very high one week after we run out of IPv4 addresses," Curran said.