Yesterday, APNIC received two more /8s from IANA, reducing the IANA global pool to just 12 /8s—5.4 percent of the usable IPv4 address space. APNIC is one of the five Regional Internet Registries (RIRs) that distribute IP addresses around the world, and IANA is part of ICANN, the body that governs the Internet. (Insofar as the Internet allows itself to be governed.)

IANA distributes addresses to the RIRs as 8-bit prefixes, which are all the addresses that share the first of the four numbers that the IPv4 address consists of. Each of these "/8s" holds 16,777,216 addresses. With eight bits there can be 256 /8 blocks, but only 221 are usable. So depending on your view of the world, the glass is either 95.3 or 94.6 percent full.

We started 2010 with 26 /8s in the IANA global pool, and now, less than ten months later, 14 of those have been given out. APNIC got earlier two-block infusions in January, April, and August, for a total of eight /8s this year. That's the same number of /8s that were given out to all five RIRs combined in 2009. But 2009 was a slow year. ARIN (North America), LACNIC (Latin America and the Caribbean), and the RIPE NCC (Europe, the Middle East, and the former Soviet Union) got two blocks each—leaving out AfriNIC (Africa). Before this year, the rule was that an RIR would be topped off in order to be able to continue operating for 18 months as soon as the amount of address space in its posession got below what's needed for 9 months of operation. However, this rule is no longer in effect. It appears that an RIR now gets two blocks when it dips below 6 months worth of space. The current status of the RIRs is as follows:

Free Use/month Months remaining AfriNIC 36.95 M 0.65 M 57 APNIC 90.66 M 9.13 M 10 ARIN 102.02 M 2.37 M 43 LACNIC 57.75 M 1.28 M 45 RIPE NCC 58.83 M 3.21 M 18

There is an agreement in effect that once five blocks remain, each RIR gets one last block. There are two options for how this will go down. The most likely is that APNIC continues to burn through two blocks every three or four months, so next year around this time they'll hit the final five, leaving APNIC with eight of the last five /8s and the other RIRs with one each. It's also possible that RIPE needs additional space just before APNIC needs blocks 7 and 8, so RIPE gets two, APNIC seven, and the others one each. At that point, global IP address solidarity will be a thing of the past: APNIC and RIPE will have enough addresses to continue business as usual for about another year at current rates, ARIN and LACNIC for around three years, and AfriNIC for nearly seven years.

Of course it's entirely possible that things could change in the meantime. In fact, we may be observing a run on the bank in the Asia-Pacific region as we speak. APNIC has already given out 97 million addresses this year, 10 million more than in the whole of 2009. In recent years, China has propelled APNIC address use upwards on a steep curve, using up no less than 50 million addresses (a quarter of worldwide use) in 2009. But China isn't going to match last year's run rate, with only 35 million new IP addresses this year so far. Other countries in the region are picking up the slack, however:

2009 2010 so far Korea 10.95 M 24.03 M India 1.53 M 6.71 M Vietnam 0.29 M 5.66 M Australia 2.64 M 4.88 M

Too bad IPv4 addresses aren't 33 bits, then we'd have a couple more decades to prepare for the inevitable—which isn't going to be pretty.