Thursday, May 14, 2009

Are We Finally Out of IPv4 Addresses?

It's been predicted for years and pooh-poohed for as many years. The Internet has gotten much bigger than first planned and the original technology is starting to get creaky with the strain. Someday, it's going to all come crashing down if nothing is done. That someday now looks like 2010.

ARIN, the American Registry for Internet Numbers, has sent out a letter to Internet Service Providers warning them that they are running out of IPv4 addresses. IPv4 or Internet Protocol Version 4 is that standard that defines Internet addresses. It defines 4 bytes or 32 bits to identify a particular piece of equipment on the Internet. That could be a server, a router, a web camera, or your PC. Those 32 bits are enough for 4.3 billion addresses. How many are already used up? According to ARIN, all but about 500 to 700 million. After that, nothing can connect to the Internet unless something else gets off. It will be take-a-number-and-stand-in-line.

Well, not really. There is an upgrade available called IPv6. That's version 6 of the Internet Protocol. IPv6 expands the address space from 32 to 128 bits. That's a factor of 4x as many bits, but trillions and trillions as many addresses. That's the beauty of binary numbers. An addition of only 1 bit doubles your capacity. It's going to be a long, long time before we can figure out how to use up all the addresses available with IPv6, even if everybody on Earth has as many IP addresses as they can possibly use and then some.

So why all the foot dragging? Companies and ISPs are complacent. They have their networks set up for IPv4 and are reluctant to upgrade the equipment and switch everything over to IPv6. All the scare stories to date have been just that. Every time it looks like the IPv4 addresses are nearly exhausted, someone invents a clever workaround like NAT (Network Address Translation) or DHCP (Dynamic Host Configuration Protocol) to make more efficient use of addresses so that fewer are needed.

The day of reckoning is surely coming. Even if all the unused addresses could be rounded up and redeployed and each address was treated like a precious resource, the demand for Internet access by individual users and equipment of all types is steadily increasing. IPv6 is just a matter of time. Like the digital TV transition and the need to split cities into multiple area codes, somebody is going to be inconvenienced and there are likely costs involved to get equipment up to the latest standards.

In the meantime, ARIN will soon start insisting on formal justification as to the need for all IPv4 address space requests. They are also asking that all organization's publicly accessible resources be at least available via IPv6 addresses. It's a modest but serious start to what may well be a mad scramble in a year or two when everyone realizes that the cupboard is really bare.

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