NSA's Lucky Break: How the U.S. Became Switchboard to the World

International phone and internet traffic flows through the United States largely because of pricing models established more than 100 years ago in the International Telecommunication Union to handle international phone calls. Under those ITU tariffs, smaller and developing countries charge higher fees to accept calls than the U.S.-based carriers do, which can make it cheaper to route phone calls through the United States than directly to a neighboring country.

While nobody outside the intelligence community knows the exact volume of international telephone and internet traffic that crosses U.S. borders, experts agree that it bounces off a handful of key telephone switches and perhaps a dozen IXPs in coastal cities near undersea fiber-optic cable landings, particularly Miami, Los Angeles, New York and the San Francisco Bay Area.

Miami sees most of the internet traffic between South America and the rest of the world, including traffic passing from one South American country to another, says Bill Manning, the managing partner of ep.net. “Basically they backhaul to the United States, do the switch and haul it back down since (it’s) cheaper than crossing their international borders.”

https://www.wired.com/2007/10/nsas-lucky-break-how-the-u-s-became-switchboard-to-the-world/