The most comprehensive maps yet of the the internet's infrastructure could help shore it up against disasters and sabotage

Join the dots (Image: Atlas at Wail/Open Street Map Contributors)

IN MANY ways the internet is like another country. It has its own communities, cultures and even currency. But its infrastructure – the fibre optic cables that span the globe, and the thousands of buildings housing servers and routers – passes through almost every nation.

Internet cartographers have tried for years to chart its extent in the physical world, in order to manage traffic and assess weaknesses. Such vulnerability was shown on 27 March, when three scuba divers were arrested for trying to cut an undersea cable off the coast of Egypt, where several critical cables come together in one of the internet’s “choke points“. And last year, superstorm Sandy’s impact on internet connectivity in New York rippled all the way to Chile, Sweden and India.

Previous attempts to map the internet have been from within, using “sniffer” software to report the IP addresses of devices visited along a particular route, which, in theory, can then be translated into geographical locations. But this approach doesn’t work, says Paul Barford at the University of Wisconsin-Madison. “After 15 years nobody can show you a map of the internet,” he says.


Such software is often inadvertently blocked by internet service providers (ISPs). Routers also try to find the shortest route between points, so sniffers end up mapping the internet’s major highways, but few of the back roads. “It leaves a very large part of the internet effectively invisible,” says Matthew Roughan at the University of Adelaide in South Australia.

Barford and Roughan head up two separate projects that are attempting to change that. Instead of relying on sniffers, they are scouring ISP databases to find published information about local networks, and piecing these together into a global map. Roughan’s Internet Topology Zoo is a growing collection of maps of individual networks. Barford’s Internet Atlas expands on this, adding crucial buildings and links between networks to flesh out the map. So far the Internet Atlas, perhaps the most comprehensive map of the physical internet, maps 10,000 such structures and 13,000 connections. Barford presented the work at the University of Cambridge on 28 March.

Both teams say that a global view of the internet’s infrastructure will be invaluable for assessing key vulnerabilities. “You need to be able to see data from multiple networks to be able to judge this type of risk,” says Roughan. For example, Honolulu stands out in the Internet Atlas as an important hub because of its mid-Pacific location, used to link countries across the ocean. Damage there would have knock-on effects throughout the Pacific Rim.

The maps can also show where planned backup cables and servers, ready to step in when the front line fails, aren’t likely to work. Cables are typically laid beside electricity wires, railways or anywhere there is an existing right of way and easy access. In Australia, for example, both primary and backup cables running from Adelaide to Perth cross 1000 kilometres of desert beside the only road between the cities. “Anything that happens to one will happen to the other,” says Roughan.

The maps show which portions of the internet are most at risk, says Barford. “They suggest where proactive disaster planning should be focused.”

The maps show areas of the internet most at risk and so where disaster planning must be focused

This article appeared in print under the headline “Building an internet atlas”