The remaining pool of unallocated IPv4 addresses could be depleted as early as December due to unprecedented levels of broadband and wireless adoption in the Asia Pacific region, experts say.
The acceleration of IPv4 address depletion is putting more pressure on network operators to migrate to IPv6, the long-anticipated upgrade to IPv4, the Internet's main communications protocol.
IPv4 uses 32-bit addresses and can support 4.3 billion devices connected directly to the Internet. IPv6, on the other hand, uses 128-bit addresses and supports a virtually unlimited number of devices -- 2 to the 128th power.
As of this week, only 6.25% of IPv4 addresses remain available to be distributed by the Internet Assigned Numbers Authority (IANA) to the five Regional Internet Registries (RIRs). The registries provide IPv4 addresses to carriers, usually in blocks of around 4,000 addresses at a time.
In the first half of 2010, IANA allocated more IPv4 addresses to the registries than in all of 2009.
"It's moving so fast now that it's hard for us to be current on it any longer," says Richard Jimmerson, CIO at the American Registry for Internet Numbers (ARIN), which provides IPv4 addresses to carriers in North America.
IANA tracks IPv4 address space in blocks of 16 million addresses, which are known in network engineering parlance as a "/8." At the beginning of 2010, IANA had 26 /8s left. Currently, IANA has 16 /8s remaining unallocated.
"We've gone through 10 /8s since the beginning of this year," Jimmerson says. "To put that in perspective, in all of 2009, we only went through eight /8s. It's very possible that the IANA free pool will deplete in December or January at the earliest."
One reason that unallocated IPv4 address space could be depleted this year is that IANA has a policy that states that when there are only five remaining /8s, it will automatically give one to each of the registries and thereby deplete the free pool overnight.
"When we get down to seven /8s, it could be a matter of days for us to get from seven to zero," Jimmerson says. "Once ARIN gets its final /8, our pool could last anywhere from one day to six months, depending on demand…The minute that carriers hear the IANA free pool has been depleted, ISPs will be sure to get their requests in."
While demand for IPv4 addresses remains flat in North America, there has been a huge surge in the Asia Pacific region this year that is likely to remain strong.
"The Asia Pacific region has very large economies that are underserved by IP addresses such as India, China and other places," Jimmerson says. "They are really seeing a big surge in broadband deployment and wireless data handset deployment, and that translates into having to have unique IP address space. That trend is likely to continue."
When the Internet runs out of IPv4 address space, new residential broadband users and new devices such as Verizon's LTE mobile devices will have IPv6-only Internet access. The best way for Web sites to serve up content to these IPv6-based users is if they support IPv6 natively. The alternative is carrier-grade network-address translation, which adds another layer of complexity to a Web site. So, if a Web site doesn't support IPv6, it is likely to disenfranchise IPv6-based users.
ARIN is urging network operators to be prepared to support IPv6 on their public-facing Web servers and mail servers by January 2012.
"Network operators need to realize that the IPv6 and the IPv4 networks are logically separate, and what they're going to be doing over the next decade or more is supporting both networks," Jimmerson says. " They need to make sure that their content, their Web servers and their mail servers all are dual-stack, so they can support both IPv4 and IPv6."
While December is the earliest date that is projected for IPv4 address depletion, it's possible that the IANA free pool of unallocated IPv4 address" space will last several months into 2011.
"IPv4 depletion is such a moving target," Jimmerson says. "The reason that we haven't given a flag date to anybody is that any flag date we give will certainly be wrong."
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