[ipv6-wg] 2007 IPv4 Address Use Report

2007 IPv4 Address Use Report

In 2007, the number of available IPv4 addresses went down from 1300.65  
million to 1122.85 million, a difference of 177.8 million addresses.  
The number of usable addresses is 3706.65 million, so on January 1,  
2007 we were at 64.9% utilization and a year later we're at 69.7%.

These figures are derived from the records published on the FTP  
servers of the five Regional Internet Registries (RIRs): AfriNIC,  
which gives out address space in Africa, APNIC (Asia-Pacific region),  
ARIN (North America), LACNIC (Latin American and the Caribbean) and  
the RIPE NCC (Europe, the former Soviet Union and the Middle East).  
There are two other ways to interpret the same data. The first is  
simply add up all the address space with a date indicating that it was  
given out in 2007. That number is 186.93 million addresses.

The third method is to compensate for ARIN's record keeping  
peculiarities (see this Internet Protocol Journal article). This  
brings the total for 2007 to no less than 196.77 million, the highest  
number ever. The second-highest was 1991 with 189 million addresses.  
The 196.77 million figure is approxmately 19% higher than the 2005 and  
2006 numbers, which were largely the same. All numbers only include  
addresses that are still in use. For the first time in many years, in  
2007 one of the old class A blocks was returned to IANA: block  
46.0.0.0/8, 16.78 million addresses in size, is now part of the global  
pool of free address space. This accounts for most of the difference  
between the 177.8 and 196.77 numbers. The status of the 221 usable  
blocks of 16.78 million address is now as follows:

Delegated to   Blocks   +/- 2007   Addresses (millions)

AfriNIC            2       +1             33.55
APNIC             26       +7            436.21
ARIN              27                     452.98
LACNIC             6       +2            100.66
RIPE NCC          26       +4            436.21
Various           49       -1            822.08
End-user          42       -1            704.64
Available         43      -12            721.42

In addition to the 43 unused blocks (721.42 million addresses) that  
IANA holds, there is additional free space in the form of addresses  
delegated from IANA to the regional internet registries, but not yet  
further delegated by the RIR in question to an ISP or end-user.

                    2006-01-01                    2007-01-01
            delegated  delegated  free    delegated  delegated  free
               TO         BY                 TO         BY

AfriNIC       16.78      6.39     10.39     33.55     11.97     21.58
APNIC        318.77    297.23     21.54    436.21    366.87     69.34
ARIN         452.98    350.48    102.50    452.98    394.08     58.90
LACNIC        67.11     42.71     24.40    100.66     57.52     43.14
RIPE NCC     369.10    317.62     51.48    436.21    378.35     57.86

Total RIRs  1224.74   1014.43    210.31   1459.61   1208.79    250.82

Various      838.86    671.26    167.60    822.08    671.48    150.60
End-user     721.42    704.64     16.78    704.64    671.09     33.55
Available    922.74     16.78    905.96    721.42     16.78    704.64

Total       3707.76   2407.11   1300.65   3707.75   2568.14   1139.61

This view uncovers two inconsistencies: block 7.0.0.0/8 that is part  
of the free space according to the IANA IPv4 address space overview  
shows up as delegated to the US Department of Defense in ARIN's  
records. Net 14.0.0.0/8 is for the "public data net" (see RFCs 3330  
and 1700) so it's not part of the regular delegation system.  
43.0.0.0/8 is delegated to "Japan Inet" by IANA. Those delegations  
used to be registered in ARIN's database but this block was  
transferred to APNIC in 2007, where it does show up in the whois  
service, but not as part of the delegated address space in the files  
on the FTP server. The total of 3707.76 (or 3707.75) million addresses  
is slightly different from the 3706.65 maximum mentioned earlier  
because the latter excludes all RFC 1918 private address space, the  
former still includes 192.168.0.0/16 and 172.16.0.0/12.

The size of address blocks given out was increasing until 2005, but  
now shows a downturn. The table below shows the number of delegations  
for a certain range of block sizes (equal or higher than the first,  
lower than the second value).

(2005 and earlier values from 2006-01-01 data, 2006 and 2007 values  
from 2007-01-01 data. No correction for the ARIN accounting method.)

                2001    2002    2003    2004    2005    2006    2007

< 1000           474     547     745    1022    1309    1507    1830
1000 - 8000     1176     897    1009    1516    1891    2265    2839
8000 - 64k       868     822    1014    1100    1039    1192    1015
64k - 500k       262     163     215     404     309     419     395
500k - 2M         39      29      46      61      60      57      62
 > 2M               5       5       6       7      18      17      24

The increase in large blocks has a very dramatic effect while the  
small blocks are insignificant, when looking at the millions of  
addresses involved:

                2001    2002    2003    2004    2005    2006    2007

< 1000          0.16    0.18    0.25    0.35    0.44    0.51    0.63
1000 - 8000     4.47    3.23    3.45    4.49    5.07    5.83    6.93
8000 - 64k     12.81   11.35   14.00   15.99   15.46   18.01   15.67
64k - 500k     32.19   20.28   25.51   42.01   34.23   50.86   50.83
500k - 2M      24.64   21.30   31.98   44.63   41.63   46.69   45.50
 > 2M           14.68   12.58   12.58   20.97   68.62   52.43   67.37
Despite the strong increase in the number of 2 million+ blocks and the  
amount of address space given out in these blocks, the average block  
size has been going down because of the very large growth in the  
numbers of smaller blocks:
Year    Blocks    Addresses (M)   Average block size

2000      2794            78.35                28043
2001      2824            88.95                31497
2002      2463            68.93                27985
2003      3035            87.77                28921
2004      4110           128.45                31252
2005      4626           165.45                35765
2006      5457           174.32                31945
2007      6165           186.92                30320

The 2568.14 million addresses currently in use aren't very evenly  
distributed over the countries in the world. The current top 15 is:

               2007-01-01   2007-01-01  change    Country

1    -    US    1408.15 M    1366.53 M     +3%    United States
2    -    JP     141.47 M     151.27 M     -6%    Japan
3   (4)   CN     135.31 M      98.02 M    +38%    China
4   (3)   EU     120.35 M     115.83 M     +4%    Multi-country in  
Europe
5    -    GB      83.50 M      93.91 M    -11%    United Kingdom
6    -    CA      73.20 M      71.32 M     +3%    Canada
7    -    DE      72.46 M      61.59 M    +18%    Germany
8    -    FR      67.79 M      58.23 M    +16%    France
9    -    KR      58.86 M      51.13 M    +15%    Korea
10   -    AU      33.43 M      30.64 M     +9%    Australia
11  (12)  IT      24.04 M      19.14 M    +26%    Italy
12  (11)  BR      23.46 M      19.27 M    +22%    Brazil
13  (16)  MX      21.50 M      16.26 M    +32%    Mexico
14  (13)  ES      20.42 M      18.69 M     +9%    Spain
15   -    NL      19.89 M      18.08 M    +10%    Netherlands

The -6% and -11% figures for the UK and Japan are once again  
anomalies: the former is the missing 43.0.0.0/8 net and in the latter  
case, ARIN and RIPE both had a record for 25.0.0.0/8 in the 2007-01-01  
data, but this was cleared up in the 2008-01-01 data.

Although the US still added more than 40 million new addresses to its  
immense existing stockpile, its growth was modest percentage-wise and  
it now holds 55% of the IPv4 address space in use, down from 57%. All  
of the other countries in the top 15 except for Canada and "EU" saw  
their address use grow faster than the 7% average. This brings the  
total for the top 15 excluding the US to 35%, up from 34%. The rest of  
the world gets the remaining 10%, up from 9%.

See http://www.bgpexpert.com/addrspace2007.php for a copy of this  
report and links to the versions for 2006 and 2005.