Last IP address going, going, gone

USC (US) — The international organization that issues Internet Protocol (IP) addresses announced this morning that there are no more free addresses available.

Computer scientist John Heidemann, who leads a research group at the University of Southern California that monitors address usage, says there is, however, some good news.

His team has completed the latest in its series of Internet censuses. They released results in the form of a detailed outline, including a 10-minute video and an interactive web browser that allows users to explore the nooks and crannies of Internet space themselves.

Heidemann says his group has found that while some of the already allocated address blocks (units of Internet real estate, ranging from 256 to more than 16 million addresses) are heavily used, many are still sparsely used—”even allowing for undercount,” the group finds, “probably only 14 percent of addresses are visible on the public Internet.”

Nevertheless, “as full allocation happens, there will be pressure to improve utilization and eventually trade underutilized areas,” the video shows.

These strategies have limits, the report notes. Better utilization, trading, and other strategies can recover “twice or four times current utilization. But requests for address double every year, so trading will only help for two years. Four billion addresses are just not enough for 7 billion people.”

That number—four billion—is the number of free addresses available under the out-of-date Internet Protocol version 4 (IPv4). The more expansive IPv6 allows many, many more addresses—1000 trillion trillion—but may involve transition costs.

Heidemann’s report comes as several organizations, including the Number Resource Organization and the Internet Assigned Numbers Authority, announced during a press conference in Miami on Feb. 3 that they have given out all the addresses, passing on most to regional authorities.

The video featured above offers a thorough background in the hows and whys of the current IPv4 address system, in which each address is a number between zero and 2 to the 32nd power (4,294,967,295), usually written in “dotted-decimal notation” as four base-10 numbers separated by periods.

Heidemann and colleagues produced their first Internet census in 2007. To do this, they sent a message (‘ping’) to each possible Internet address. (The video also explains the pinging process.)

At the time, some 2.8 billion of the 4.3 billion possible addresses had been allocated; today more than 3.5 billion are allocated.

The current effort was funded by Department of Homeland Security Science and Technology Directorate and the National Science Foundation.

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