Internet body may use up IPv4 addresses this week

All its addresses may be given out to regional entities, a milestone on the path to an IPv6-only Internet

The current crop of Internet addresses could start to disappear this week if a regional Internet registry makes one more request for two blocks of addresses.

APNIC (Asia Pacific Network Information Centre) is eligible to request two large blocks of IPv4 (Internet Protocol, Version 4) addresses, because users have been snapping up its existing stock quickly enough, according to Leo Vegoda, manager of number resources at the Internet Assigned Numbers Authority. Because there are only seven of these large blocks left, that allocation to APNIC would activate a policy for the IANA to hand out the last five blocks to the five regional registries, Vegoda said.

[ See also: IPv6 basics: Getting started with IPv6 ]

Experts have been warning ISPs (Internet service providers) and enterprises for years that IPv4 addresses are destined to run out soon. Various technical fixes have staved off that day, but the assignment of those final blocks would leave the ultimate supply of those addresses tapped out. This would mark a milestone on the path to an Internet based totally on the latest protocol, IPv6.

It typically takes about two business days to fulfill a request by a regional Internet registry (RIR) such as APNIC for more address blocks, and it can be done more quickly if needed, Vegoda said. The IANA does not comment on address allocations until they are made, but "it would certainly be possible for us to process a request before the end of this week," he said. APNIC, based in Brisbane, Australia, was not immediately available to comment on a possible address request.

The timing suggests that predictions that IPv4 addresses will be depleted very soon may be correct. Martin Levy, director of IPv6 strategy at ISP Hurricane Electric, predicted last week that the IANA's stockpile would be exhausted this week. At the same time, two online "clocks" that estimate the date of IPv4 depletion are showing that this event should have passed already or would occur very soon. On Monday, The IPv4 Depletion Site showed the "IANA depletion date" had just arrived. A long-running IPv4 clock at forecast the IANA running out on Feb. 2.

The IANA is the part of ICANN (Internet Corporation for Assigned Names and Numbers) that allocates IP addresses to the RIRs. The regional organizations, in turn, fulfill requests by ISPs and other customers in their regions for smaller blocks of addresses. After the IANA hands out the last of its so-called "/8" blocks, each of which contains about 16 million addresses, the RIRs will have no additional supply to turn to after they have fulfilled their customers' requests.

This won't mean that suddenly no user can get a new IPv4 address, Vegoda noted. In addition to the remaining numbers held by the RIRs, there are some addresses left in older blocks assigned before the RIRs were established, which the RIRs have split up among themselves. But given the fast adoption of new addresses in some parts of the world, those resources might be used up soon.

For example, the addresses available from APNIC have been depleted by more than one-third since Jan. 12, according to data on the organization's website. On Jan. 12, APNIC's free addresses added up to 2.26 of the large /8 blocks. On Tuesday, the latest day for which the agency has statistics, the remaining addresses totaled only 1.4 blocks, or approximately 22.4 million addresses.

The rate of requests to RIRs for addresses is probably speeding up partly because applicants are worried that IPv4 addresses will run out, Vegoda said.

"I'm sure that some of these ISPs brought forward deployment plans that they were looking at doing later in the year and thought, 'If we don't get addresses now, we won't be able to do this particular deployment,'" Vegoda said. "They would be inhuman if they had done something different."

However, he said he was confident that everyone requesting the addresses would use them. Some observers have expressed fear that private entities might stockpile addresses just to sell them on a heated market.

An RIR is entitled to ask for more addresses based on how fast it is assigning addresses and how many it has left, Vegoda said. For the Asia-Pacific, North American and European registries, that means being able to ask for new blocks of addresses if they are on a path to running out within nine months. (The Latin American and African RIRs are handing out addresses less quickly because demand is lower for them.) At its current rate, APNIC could need two /8 blocks within nine months, Vegoda said.

IPv4, instituted in 1983, allows for only about 4.3 billion addresses, and from the beginning there have only been 256 of the /8 blocks. Most are already allocated, and many are reserved for special uses such as multicasting of video streams.

IPv6 has a much larger address space, which allows for an almost limitless number of unique addresses. The IANA allocates IPv6 addresses in a similar way to IPv4, except in much larger "/12" blocks, Vegoda said.

The expanded address space is expected to be most critical to users in quickly developing countries such as China and India, as well as for the many new mobile devices being used for Internet access. The transition to IPv6 will be gradual, but even an enterprise that has enough IPv4 addresses should start supporting IPv6 in order to reach the new end points that won't be able to get IPv4 addresses, Vegoda said. Otherwise, they eventually will need to go through devices on ISP networks that translate between the two protocols. Those could introduce delays, and possibly communication problems if they were incompatible with certain protocols, he said.

Google, Facebook, Cisco Systems, Verizon Business and other major vendors and service providers will take part in World IPv6 Day in June, a global test of the new protocol organized by the Internet Society. For 24 hours, the participating companies will run their public websites on both IPv4 and IPv6.

Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen's e-mail address is

Copyright © 2011 IDG Communications, Inc.

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