The Internet routes packets of data from one Internet protocol (IP) address to another. Every Internet-connected device anywhere in the world has its own IP address.

This month’s World IPv6 Day served as a test run for a protocol that should dramatically increase how many devices can be connected to the Internet. The new protocol will be crucial if many more objects—including light bulbs, kitchen appliances, and environmental sensors—are to have IP addresses, connect to the Internet, and send and receive data.

What needs replacement is called Internet protocol version 4 (IPv4). This has been the basis for communication between devices since 1981, and it allows for nearly 4.3 billion addresses. The new system allows for around 340 trillion, trillion, trillion addresses—nearly 50 octillion for every person on earth.

IPv4 by country: The share of the world’s total of 3.7 billion usable IPv4 addresses held by different countries as of June 13, 2011.
Credit: Iljitsch van Beijnum

If you live in the U.S. you’re less likely than people elsewhere to notice the need to switch the Internet to IPv6. Each of a range of large U.S.-based companies and organizations, including Apple, IBM, HP, Ford, and MIT, were  allocated a block of nearly 17 million addresses soon after IPv4 was introduced, and a large portion of those addresses remain unused.

In countries where the number of people connecting online is growing fast, the problem is more urgent. China has nearly 400 million Internet users but only about 330 million IP addresses. Compare those figures with those for the United States, which holds about 1.5 billion addresses—40 percent of the total of 3.7 billion usable addresses. (The other half billion are unusable for a variety of reasons.) India, with its population of roughly 1.1 billion, has only about 35 million addresses.

Internet population: The proportion of countries’ populations using the Internet.
Source: World Bank. Last updated April 2011.

Discrepancies like these no doubt explain the fact that the region managed by APNIC, the Asia Pacific Network Information Centre, is leading the rest of the world in IPv6 deployment.

The world’s Internet registries: Five regional Internet registries allocate IP addresses. These are AfriNIC, the African Network Information Center; APNIC, the Asia Pacific Network Information Centre; ARIN, the American Registry for Internet Numbers; LACNIC, the Internet Registry for Latin America and the Caribbean; and RIPE NCC, the Réseaux IP Européens Network Coordination Centre.
Source: Wikimedia Commons

Changing rates of IPv4 address allocation: The average number of IPv4 addresses that each registry allocated per month for the previous six months varies greatly by region. The vertical axis is calibrated in “/8” blocks, each of which is roughly equivalent to 16.8 million IP numbers.
Source: RIPE NCC

IPv6 adoption: The percentage of each registry’s networks that have announced support for IPv6.
Source: RIPE NCC