The Asia Pacific Network Information Centre (APNIC) has run out of all but a handful of IPv4 addresses that it is holding in reserve for start-up network operators.

APNIC is the first of the Internet's five regional Internet registries to deplete its free pool of IPv4 address space.

APNIC's news is another sign that CIOs and other IT executives need to begin migrating to IPv6, the long-anticipated upgrade to the Internet's main communications protocol known as IPv4.

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"For anybody who hasn't figured out that it's time to do IPv6, this is another wake-up call for them," says Owen DeLong, an IPv6 evangelist at Hurricane Electric and a member of the board of the American Registry for Internet Numbers (ARIN), the North American counterpart to APNIC.

Any CIO who isn't planning for IPv6 is "driving toward a brick wall and closing your eyes and hoping that it's going to disappear before you get there," DeLong says. Ignoring IPv6 "is not the best strategy."

Most IPv4 address space is expected to be handed out by the regional Internet registries by the end of 2011.

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.

The Asia Pacific region has been gobbling up the most IPv4 address space in recent years; APNIC has apparently distributed more than 32 million IPv4 addresses to network operators in this region in the last two months alone.

APNIC has depleted its IPv4 address space "dramatically faster than people expected," DeLong says. "My guess is that a lot of operators in the Asia Pacific region realized the time of IPv4 depletion was drawing near and they rushed to get their applications in."

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APNIC is holding 16.7 million IPv4 addresses -- dubbed a /8 in network engineering terms -- in reserve to distribute in tiny allotments of around 1,000 addresses each to new and emerging IPv6-based networks so they can continue to communicate with the largely IPv4-based Internet infrastructure.

ARIN, which doles out IPv4 and IPv6 address space to companies operating in North America, predicts that it will run out of IPv4 addresses this fall.

"RIPE [the European Internet registry] is going to be the next one to run out. I wouldn't count on them making it until July," DeLong says. "I think ARIN will make it to the end of this year; maybe we'll run out in October or November."

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One wild card is whether Asian network operators who also do business in North America will begin requesting IPv4 address space from ARIN now that APNIC has none to give.

"This will probably accelerate consumption in the ARIN region slightly and in RIPE for the same reason because there are a very large number of companies that have operations in Asia, Europe and the Americas," DeLong says.

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This story, "Asia out of IPv4 Addresses" was originally published by Network World .