IPv6 Adoption Now of 'Paramount Importance' as IPv4 Addresses Run Out

The "IPocalypse" is turning out to be a mild global event, as -pocalypses go. End users won't begin to see the effects for months, and there should be little disruption when it does hit. But the end of IPv4 means that the transition to IPv6 needs to start now, according to ICANN.

• By Leila Meyer
• 02/04/11

On Feb. 3, 2011, the Internet Corporation for Assigned Names and Numbers (ICANN) announced that the last remaining Internet protocol version 4 (IPv4) IP addresses had been allocated, although it may take a few months before the effects of this event trickle down to Internet users. IPv4 will be succeeded by a new system of IP addressing called Internet protocol version 6 (IPv6).

Every Internet-connected device in the world--every server, every router, every smart phone--has a unique IP address that identifies it on the Internet so other devices can locate and communicate with it. An example of an IPv4 address is 192.0.32.10.

IPv4 was established in the early 1980s with a total capacity of about 4 billion unique IP addresses. At the time, that was considered to be more than enough IP addresses. Since then, the number of devices connected to the Internet has exploded, leading us to the current situation, which some people have dubbed the "IPocalypse."

Although all IPv4 addresses have now been allocated, the end for IPv4 isn't quite yet nigh. ICANN allocates the IP addresses among the five regional Internet registries (RIRs) around the world. The RIRs in turn allocate their share of IP addresses among the Internet service providers (ISPs) in their region, and the ISPs assign the addresses to individual subscribers. On Feb. 3, ICANN allocated the last of the IPv4 addresses to the RIRs, but it may take a few more months before the RIRs allocate all of those remaining IP addresses to the ISPs, and the ISPs allocate them to their subscriber's devices.

"This is a major turning point in the on-going development of the Internet," said Rod Beckstrom, president and CEO of ICANN in a news release. "No one was caught off guard by this. The Internet technical community has been planning for IPv4 depletion for some time. But it means the adoption of IPv6 is now of paramount importance, since it will allow the Internet to continue its amazing growth and foster the global innovation we've all come to expect."

IPv6 has a capacity of 340 undecillion unique IP addresses. That's a billion-trillion times more capacity than the IPv4 addressing system. So, using the new IPv6 addressing scheme, the Internet won't run out of unique addresses any time soon.

While IPv4 addresses consist of four three-digit segments separated by dots, IPv6 addresses consist of eight four-hexadecimal-character segments separated by colons. An example of an IPv6 address is 2001:0db8::53. Two colons side-by-side in an IPv6 address indicate that the segments between them contain only zeros.

Once the ISPs run out of IPv4 addresses, they will have to switch over to the new IPv6 system. Most new computers, routers, and other Internet-connected devices are ready for the switchover to IPv6. However, older equipment may not be able to support IPv6, and will lose its ability to connect to the Internet when the switchover occurs.