The Depleting IPv4 address space had been of concern since nearly a decade. The concerns transformed into efforts that lead to the evolution of IPv6.
With the current pace of depletion of IPv4, we would run out of address space within a year. The latest usage report is out which gives us exact usage numbers: 80.5% address space is used, up from 75.3% of last year (2009 begining).
As of Jan 1st, 2010, the number of unused IPv4 addresses is 722.18 million. On January 1, 2009, this was 925.58 million. So in 2009, 203.4 million addresses were used up. This is the first time since the introduction of CIDR in 1993 that the number of addresses used in a year has topped 200 million. With 3706.65 million usable addresses, 80.5% of the available IPv4 addresses are now in some kind of use, up from 75.3% a year ago. So the depletion of the IPv4 address reserves is continuing in much the same way as in previous years:
Date Addresses free Used up 2006-01-01 1468.61 M 2007-01-01 1300.65 M 167.96 M 2008-01-01 1122.85 M 177.80 M 2009-01-01 925.58 M 197.27 M 2010-01-01 722.18 M 203.40 M
These figures are derived from from the Internet Assigned Numbers Authority’s IANA IPv4 Address Space Registry page. Interestingly, the 2985 million addresses currently in use aren’t very evenly distributed over the countries in the world.
However, more interestingly, the US now holds 50.1% of the IPv4 address space in use, down from 52.4% last year. This means where US has seen some saturation in IPv4 usage, other countries have been still using more.
With the growing pace, we are not far from when they exhaust. By some date in 2012, IPv4 run out of space. But, this won’t happen. IPv6 adoption has been mandated in certain areas like for ISPs starting from this year, 2010. With the Adoption of IPv6, we’ll get improved security, easier manageability, and a wider space to exploit.
For the transitions, IPv4-in-IPv6 tunnels are being used extensively. These tunnels will stay around for next couple of years till IPv4 and IPv6 co-exist. Perhaps this would be forever if not for a decade.