We are running out of IPv4 Internet addresses, but who is using them all up? The IP address space usage per capita differs greatly between nations, which points to a digital divide.
If we would distribute IPv4 addresses uniformly over the world population, there would be less than 1 address per person. In fact, on the average, 0.54 addresses would be available per person (including all babies, etc). In 2006 this number was 0.57, population has increased in the meantime. The actual use is 0.45 (up from 0.32 in 2006).
But addresses are not uniformly distributed. There is a digital divide between western countries and developing countries. The top user (not counting some mini states) is the US, where wasteful pre-CIDR address allocations have led to an average of more than 4 addresses per person. A few dozen countries have more than their fair share (i.e. 0.54) addresses per person, and almost two dozen have more that 1 address per person allocated.
Utilization is still growing rapidly. Over 30, mostly developing, countries have more than doubled their address utilization per capita in the past 4 years. In addition, most developed countries (with the notable exception of the US) have seriously (30-60%) increased their utilizations.
This growth is clearly unsustainable within the IPv4 address space. Not every country can have these utilization levels. The hunger for new addresses is greatest in China (currently at 1 IPv4 address per 4 inhabitants) and India (1 address per 53 inhabitants). To put these at the modest level of 1 address per inhabitant requires more than 2.2 billion addresses, where there are currently only 290 million left, according to http://www.potaroo.net/tools/ipv4/. Given these numbers and the overall strong growth, any hopes of being able to reuse space that is allocated but not used (i.e. pre-CIDR) are futile. This demand dwarfs the entire US allocation.
IPv6 is supposed to solve the address space problem. Is it progressing? For IPv6 allocations the per capita metric is a bit moot as there is no scarcity. Still, there is an interesting divide. Quite a number of countries have no allocated IPv6 address space at all. A few have pilots, with utilizations less than 1 percent. The largest utilizations are in Sweden and in the Asia Pacific region, where a number of countries have hundreds of IPv6 blocks (/64 each) per inhabitant. The US is in 8th place, after Vietnam and Indonesia but, somewhat surprisingly, before China.
The full data of this analysis can be found in a Google Docs spreadsheet, see http://twurl.nl/q416tl
I’d also like to acknowledge Iljitsch van Beijnum who has provided the address allocation data. http://www.bgpexpert.com/addrspace2009.php