The final chunks of IPv4 addresses were doled out last week, and after those are distributed to their ultimate address holders, anyone looking for a new address will have to turn to the IPv6 protocol.

With IPv4 there were a total of 4.3 billion addresses possible, and nobody really anticipated they'd start running out so quickly. While IPv6 has been a standard for more than 10 years, there's been little motivation to upgrade networks to handle it. Service providers can make customers share IP addresses for most communications, notes Iljitsch van Beijnum in a post at Ars Technica, but that doesn't work so well for two end users trying to connect directly over such technologies as instant messaging, VoIP or P2P file sharing.

Before the end of the year, the Regional Internet Registry for the Asia-Pacific region (one of five such registries) is likely to get a request from a large ISP and it won't be able to fulfill it, he predicts. This registry used up nearly 24 million IP addresses in January. For the North American registry, this turning point will likely come in 2012, he predicts.

With IPv6, there will be effectively an infinite number of addresses. Experts expect the IPv6 transition to take five to 10 years, and in the meantime there will likely be a black market for IP addresses, reports InformationWeek's Thomas Claburn.

To give the transitions some momentum, the Internet Society is holding a World IPv6 Day this year on June 8. Several major network providers plan to enable the new protocol for a test period that day.

For more:
- see Iljitsch van Beijnum's post at Ars Technica
- see Thomas Claburn's post at InformationWeek

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