IPv4 Will Bleed to Death in 2011, Says ARIN

The Internet is likely to run out of IPv4 address spaces by early next year, Richard Jimmerson, CIO of ARIN, the American Registry for Internet Numbers, warned his audience during a speech Wednesday at LISA, the 24th Large Installation System Administration Conference, being held in San Jose, Calif., through Friday.

"By the end of the first quarter next year, the IANA free pool of IPv4 addresses will deplete," Jimmerson said.

IANA, the Internet Assigned Numbers Authority allocates and maintains domain names, coordinates the global pool of IP addresses and manages the numbering systems of Internet protocols, among other things.

Where Have All the Addresses Gone?

The IANA has only 12 blocks of /8s left. A /8, pronounced "slash eight," is a block of approximately 16 million unassigned IPv4 addresses. [*Correction - Dec. 2, 2010] IANA doles out one or two /8s at a time to regional Internet registries (RIRs) such as ARIN on request.

An RIR manages the allocation and registration of Internet number resources within a particular region of the world. ARIN is one of five RIRs, and its area of coverage is North America and parts of the Caribbean.

Although 12 /8s seems like a lot of IPv4 addresses, they can go very quickly. Once the IANA has five remaining /8s left, it will allocate one to each of the RIRs, at which point each RIR will hold between one and three /8s.

That's up to 192 million IPv4 addresses for each RIR, enough to provide about two-thirds the population of the United States with one address each So why the fuss?

"There may be a lot of pent-up demand out there for IPv4 addresses from large organizations that are working their way through the process," Jimmerson explained. "If the top 10 providers within the U.S. and Canada came in at one time and all ARIN had left was one /8, they could deplete it within one day."

Scrambling for the Crumbs

There are lots of underutilized blocks of IPv4 addresses that have already been allocated, and ARIN is trying to reclaim them, sometimes successfully.

"We just received a /8 block at ARIN last month," Jimmerson said. "But do not allow the fact that you see us getting these back to convince you that we won't run out. Getting an entire /8 back extends the life of IPv4 by a few weeks."

LTE 4G services that are rolling out worldwide are going to be another drain on IPv4 addresses, Jimmerson said. "Some of the service providers will use IPv6 to provide that service and others will use IPv4, and there's nothing we can do to prevent them from using IPv4. If they requested more IPv4 addresses because they're rolling out a new service, we'll issue the addresses to them."