IPv4 addresses have been used up

The current crop of Internet addresses could start to disappear this week if a regional Internet registry makes one more request for two blocks of addresses.

APNIC (Asia Pacific Network Information Centre) is eligible to request two large blocks of IPv4 (Internet Protocol, Version 4) addresses, because users have been snapping up its existing stock quickly enough, according to Leo Vegoda, manager of number resources at the Internet Assigned Numbers Authority. Because there are only seven of these large blocks left, that allocation to APNIC would activate a policy for the IANA to hand out the last five blocks to the five regional registries, Vegoda said.

Experts have been warning ISPs (Internet service providers) and enterprises for years that IPv4 addresses are destined to run out soon. Various technical fixes have staved off that day, but the assignment of those final blocks would leave the ultimate supply of those addresses tapped out. This would mark a milestone on the path to an Internet based totally on the latest protocol, IPv6.

IPv6 has a much larger address space, which allows for an almost limitless number of unique addresses. The IANA allocates IPv6 addresses in a similar way to IPv4, except in much larger "/12" blocks, Vegoda said.

The expanded address space is expected to be most critical to users in quickly developing countries such as China and India, as well as for the many new mobile devices being used for Internet access. The transition to IPv6 will be gradual, but even an enterprise that has enough IPv4 addresses should start supporting IPv6 in order to reach the new end points that won't be able to get IPv4 addresses, Vegoda said. Otherwise, they eventually will need to go through devices on ISP networks that translate between the two protocols. Those could introduce delays, and possibly communication problems if they were incompatible with certain protocols, he said.

Google, Facebook, Cisco Systems, Verizon Business and other major vendors and service providers will take part in World IPv6 Day in June, a global test of the new protocol organized by the Internet Society. For 24 hours, the participating companies will run their public websites on both IPv4 and IPv6.


由「IPv4」向「IPv6」轉型是個巨大工程，除了所有終端用戶，都必須更換終端設備接入網際網路的路由器或調製解調器之外，所有網站和網際網路服務商，也都必須全面改造，提供適用於「IPv6」協議的終端設備入網「接口」。很多網站和網際網路服務商認為，這種改造太費「周折」，因而一直堅持使用基於「IPv4」協議的網絡接入標準。