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And then there were 12

This week we allocated two more /8s, this time to APNIC, the Regional Internet Registry (RIR) for the Asia Pacific region. There are now just 12 unallocated unicast IPv4 /8s.

Chart of the decreasing pool of unallocated /8sChart of the decreasing pool of unallocated /8s

If you look at the chart above (click to enlarge) you can see that the number of unallocated /8s has now halved since the start of the year. In 2010, we have been allocating IPv4 address space at a rate of more than one /8 per month.

So does this mean that the last /8 will be allocated in about another 10 months time? Probably not. It is hard to predict the exact rate at which addresses will be allocated. We know that the last five /8s will all be allocated on a single day. This is because the Global Policy for the Allocation of the Remaining IPv4 Address Space requires us to allocate one /8 to each RIR when the pool falls to five /8s. An RIR will request additional IPv4 addresses, be allocated one or more /8s and that event will trigger the last allocation of IPv4 space from IANA to the RIRs.

For the last few years, Geoff Huston has been using mathematical modelling to project the changing set of dates for when the IANA pool of unallocated /8s will be empty and when the RIRs’ own pools will follow. At the moment his site predicts June 2011 for the IANA pool with the RIRs following about six months later. Of course, his site models future trends based on historical behaviour and people might well act differently in the future than they have in the past, so we might see something different but at this point we are looking at fine detail rather than significant extensions.

So we can’t give you a precise date for when the final allocations will be made but we can say “not long now!”


    Domain Name System
    Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as"""" is not an IDN."