The Internet Is Full—We’ve Run Out of IP Addresses

If you do the math, four combinations of 0 to 255 gives you a little over four billion possible IP addresses. Four billion sounds like a lot, but the number of devices connecting to the Internet is exploding! Internet access is now baked into smartphones, tablets, televisions, DVD players, video game consoles, utility meters, thermostats, appliances, picture frames, and more. Another problem is a big chunk of existing addresses weren’t allocated efficiently, and these can’t be easily reclaimed from the corporations, universities, and other organizations that initially received them. All of this means that we’ve run out of IP addresses. In February 2011 the last batches were made available to regional Internet registries and were expected to be distributed a few months later.J. Biggs, “Everybody Panic: Why We’re Running Out of IP Addresses and What’s Going to Happen Now, ” CrunchGear, February 2, 2011.

There are some schemes to help delay the impact of this IP address drought. For example, a technique known as NAT (network address translation) uses a gateway that allows multiple devices to share a single IP address. But NAT slows down Internet access and is complex, cumbersome, and expensive to administer.S. Shankland, “Google Tries to Break IPv6 Logjam by Own Example, ” CNET, March 27, 2009.

The only long-term solution is to shift to a new IP scheme. Fortunately, one was developed more than a decade ago. IPv6 increases the possible address space from the 2³² (4, 294, 967, 296) addresses used in the current system (called IPv4) to a new theoretical limit of 2¹²⁸ addresses, which is a really big number—bigger than 34 with 37 zeros after it. That’s more IPv6 addresses than there are gains of sand on the earth.V. Kopytoff, “Happy IPv6 Day, ” New York Times, June 8, 2011.

But not all the news is good. Unfortunately, IPv6 isn’t backward compatible with IPv4, and the transition to the new standard has been painfully slow. This gives us the equivalent of many islands of IPv6 in a sea of IPv4, with translation between the two schemes happening when these networks come together. While most modern hardware and operating systems providers now support IPv6, converting a network to IPv6 currently involves a lot of cost with little short-term benefit.S. Shankland, “Google Tries to Break IPv6 Logjam by Own Example, ” CNET, March 27, 2009. Upgrading may take years and is likely to result in rollout problems. David Conrad, a general manager at Internet Assigned Numbers Authority (IANA), the agency that grants permission to use IP addresses, has said, “I suspect we are actually beyond a reasonable time frame where there won’t be some disruption. It’s just a question of how much.”B. Arnoldy, “IP Address Shortage to Limit Internet Access, ” USA Today, August 3, 2007.

Some organizations have stepped up to try to hasten transition. Google has made most of its services IPv6 accessible, the U.S. government has mandated IPv6 support for most agencies, China has spurred conversion within its borders, Comcast and Verizon have major IPv6 rollouts under way, and over 400 Web sites have already tested their readiness for the transition on IPv6 Day. While the transition will be slow, when wide scale deployment does arrive, IPv6 will offer other benefits, including potentially improving the speed, reliability, and security of the Internet.