Mesh Networking

From the NYTimes



Wireless routers attached to rooftops in Sayada form a local network that the developers say is more secure than the Internet. CreditSamuel Aranda for The New York Times

SAYADA, Tunisia — This Mediterranean fishing town, with its low, whitewashed buildings and sleepy port, is an unlikely spot for an experiment in rewiring the global Internet. But residents here have a surprising level of digital savvy and sharp memories of how the Internet can be misused.

A group of academics and computer enthusiasts who took part in the 2011 uprising in Tunisia that overthrew a government deeply invested in digital surveillance have helped their town become a test case for an alternative: a physically separate, local network made up of cleverly programmed antennas scattered about on rooftops.

The State Department provided $2.8 million to a team of American hackers, community activists and software geeks to develop the system, called a mesh network, as a way for dissidents abroad to communicate more freely and securely than they can on the open Internet. One target that is sure to start debate is Cuba; the United States Agency for International Development has pledged $4.3 million to create mesh networks there.

Even before the network in Sayada went live in December, pilot projects financed in part by the State Department proved that the mesh could serve residents in poor neighborhoods in Detroit and function as a digital lifeline in part of Brooklyn during Hurricane Sandy. But just like their overseas counterparts, Americans increasingly cite fears of government snooping in explaining the appeal of mesh networks.

“There’s so much invasion of privacy on the Internet,” said Michael Holbrook, of Detroit, referring to surveillance by the National Security Agency. “The N.S.A. is all over it,” he added. “Anything that can help to mitigate that policy, I’m all for it.”

Since this mesh project began three years ago, its original aim — foiling government spies — has become an awkward subject for United States government officials who backed the project and some of the technical experts carrying it out. That is because the N.S.A., as described in secret documents leaked by the former contractor Edward J. Snowden, has been shown to be a global Internet spy with few, if any, peers.

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How to Make a Mesh Network

A neighborhood does not need the Internet to create a local network if residents perch small routers throughout the area to produce a mesh.



ROUTERSWireless routers outfitted with special software are fastened to church steeples, bolted to window ledges and perched atop rooftops.

LINE-OF-SIGHT VIEW Each router must have an unobstructed view of at least one other router, so that the software can create a network linking all the hardware together using wireless signals.

SERVER A server can be connected to the network to provide it with secure chat applications, electronic books, maps and other information.

“Exactly at the time that the N.S.A. was developing the technology that Snowden has disclosed, the State Department was funding some of the most powerful digital tools to protect freedom of expression around the world,” said Ben Scott, a former State Department official who supported the financing and is now at a Berlin policy nonprofit, the New Responsibilities Foundation. “It is in my mind one of the great, unreported ironies of the first Obama administration.”

Sascha Meinrath, founder of the Open Technology Institute at the New America Foundation, a nonpartisan research group in Washington that has been developing the mesh system, said that his group has had “hundreds of queries from across the U.S.” since the Snowden leaks began. “People are asking us, how do they protect their privacy?” Mr. Meinrath said.

He is quick to point out that nothing is foolproof against determined surveillance, whether American or foreign. “The technology is built from the ground up to be resistant to outside snooping,” Mr. Meinrath said, “but it’s not a silver bullet.”

Even so, it is clear that the United States sees Sayada as a test of the concept before it is deployed in more contested zones. The United States Agency for International Development “awarded a three-year grant to the New America Foundation to make this platform available for adoption in Cuba,” said Matt Herrick, a spokesman for the agency, which recentlystirred controversy by financing a Twitter-like social media site in Cuba. As for the mesh project, Mr. Herrick said, “We are reviewing the program, and it is not operational in Cuba at this time. No one has traveled to Cuba for this grant.”

Radio Free Asia, a United States government-financed nonprofit, has given $1 million to explore multiple overseas deployments. The countries involved have not been revealed, Mr. Meinrath said, adding, “I can’t talk about specific locations because lives could be at risk.”

The citizens of Sayada — population 14,000 — are more focused on using the mesh for local governance and community building than beating surveillance since President Zine el-Abidine Ben Ali was ousted in 2011, said Nizar Kerkeni, 39, a resident and professor of computer science at the nearby University of Monastir.

The mesh network blankets areas of town including the main street, the weekly market, the town hall and the train station, and users have access to a local server containing Wikipedia in French and Arabic, town street maps, 2,500 free books in French, and an app for secure chatting and file sharing.

The mesh is not linked to the wider Internet, Professor Kerkeni says — a point in his favor when he invites families to connect in this Muslim community. “Some parents ask me if it is safe to connect to the server,” he said. “They don’t allow their little children to connect to the Internet. I say, ‘I know it’s safe.’ ”

The mesh software, called Commotion, is a major redesign of systems that have been run for years by experts across Europe, said Mr. Meinrath, who is now director of the New America Foundation’s X-Lab. The idea, he said, was to take the technology out of what he calls “the geekosphere” and make it accessible to the public. (Commotion is available to download free from the project’s website.)

The open Internet is difficult to operate securely, in part because it acts as both a routing system for data and a sort of giant electronic phone book. The simplest action — say, calling up a website or sending an email — involves communicating with multiple servers and routers along numerous paths.

Mesh allows users in a local area, from a few square blocks to an entire city, to create a network that is physically distinct from the Internet. Wireless routers that cost $50 to $80 each are attached to rooftops, lashed to balconies and screwed to the ledges of apartment buildings. As long as each router has an unobstructed view to one or two others and the Commotion software has been set up, the routers automatically form a mesh network, said Ryan Gerety, a senior field analyst at the foundation.


Uri House led the creation of a mesh network in Detroit that has served as a low-cost gateway to wireless Internet access. CreditFred R. Conrad/The New York Times

“I just put my router up, and it will connect to anything it sees,” Ms. Gerety said. “You just keep putting up more routers.”

The same routers can provide access to anyone with a wireless device in range. The system’s simplicity seems undeniable: In Tunisia, Ms. Gerety and two colleagues worked with Professor Kerkeni to set up workshops with about 50 local residents. Over two weekends in December, 13 routers and a functioning mesh were put in place.

There are some drawbacks, as communications can slow when signals make multiple “hops” from one router to another, leading some Internet experts to question how large a single mesh could grow. Other experts counter that mesh networks in Europe, including some serving large sections of Berlin,Vienna and Barcelona, have thousands of routers, although they require highly technical skills.