The final blocks of IPv4 (Internet Protocol version 4) addresses could be handed out by early next year, says the Number Resources Organisation (NRO).
The global body in charge of allocating internet addresses said these allocations would mark a depletion at the global level of IPv4 addresses - something that has been anticipated for years - and put further pressure on network operators to switch to the newer IPv6 address system, which has massively more addresses available.
After a recent allocation of IPv4 numbers to APNIC, the Regional Internet Registry (RIR) for the Asia Pacific region, the NRO said that the global pool of free addresses it manages now stands at just 12 blocks. Each block represents 16 million addresses, or 1/256th of the roughly four billion IPv4 addresses available.
"This is a major milestone in the life of the internet, and means that allocation of the last blocks of IPv4 to the RIRs is imminent," said Axel Pawlik, NRO chairman. "It is critical that all internet stakeholders take definitive action now to ensure the timely adoption of IPv6."
IP addresses lie at the heart of communication on the internet. Each computer, server and router connected to the internet needs its own address and traffic is routed across the global network using these addresses.
The IPv4 addresses were defined in the early eighties. At the time the internet consisted largely of universities and research labs and the 32bit addresses were deemed sufficient, but about 10 years later people began worrying about a future day when IPv4 addresses would run out.
Those worries increased in the mid-nineties when businesses and home users began connecting to the Internet. At about the same time, in 1995, the Internet Engineering Task Force published the specification for a new version of the Internet Protocol, IPv6, which moved from 32bit addresses to 128bit addresses.
The new protocol brought a massive increase in the number of available addresses, but the two systems were incompatible so adoption was slow. Technologies like NAT (network address translation), which allow several devices to share the same IPv4 address, have delayed the inevitable exhaustion of IPv4 addresses, but now that moment is near.
The NRO issues blocks of numbers to five regional registries, which in turn issue them to companies and organisations in their respective regions. The final five blocks will be distributed equally to the registries, meaning there are only seven more blocks available under the normal distribution system, the NRO said. Current depletion rates point to NRO issuing the final blocks in early 2011, it said.
The addresses will be held by the regional registries for issue in their region, so the actual issue of the final IPv4 addresses to end-users won't come until sometime later in 2011.
The NRO issuing its final IPv4 address blocks shouldn't mean a big change for end users. The switch to IPv6 is already well under way and much of the central infrastructure of the Internet is already running on the protocol. While vast portions of the network are yet to be converted, there doesn't appear to be a last-minute rush for IPv4 addresses. That indicates "strong momentum" behind the adoption of IPv6, NRO said.
The NRO acts as a coordinating body for the five regional Internet registries, which are: AfriNIC, serving Africa; APNIC, serving the Asia-Pacific region; ARIN, serving North America and many Caribbean nations; LACNIC, serving Latin America and some Caribbean nations; and RIPE, serving Europe, the Middle East and parts of Central Asia.
See also: Less than 10% of IPv4 addresses remain