[Image: Courtesy of Terremark, via the Atlantic].

Andrew Blum has a short piece up at the Atlantic today about the geography of "internet choke points," and the threat of a "kill switch" that would allow countries (like Egypt) to turn off the internet on a national scale.

After all, Blum writes, "it's worth remembering that the Internet is a physical network," with physical vulnerabilities. "It matters who controls the nodes." Indeed, he adds, "what's often forgotten is that those networks actually have to physically connect—one router to another—often through something as simple and tangible as a yellow-jacketed fiber-optic cable. It's safe to suspect a network engineer in Egypt had a few of them dangling in his hands last night.

Blum specifically refers to a high-security building in Miami owned by Terremark; it is "the physical meeting point for more than 160 networks from around the world," and thus just one example of what Blum calls an internet "choke point." These international networks "meet there because of the building's excellent security, its redundant power systems, and its thick concrete walls, designed to survive a category 5 hurricane. But above all, they meet there because the building is 'carrier-neutral.' It's a Switzerland of the Internet, an unallied territory where competing networks can connect to each other."

But, as he points out, this neutrality is by no means guaranteed—and is even now subject to change.