In the aftermath of the recent Internet blackout in Egypt, there has been a great deal of discussion about the prospect of similar action in the United States. With due respect to Sinclair Lewis’s warning against complacency on the basis of American exceptionalism, it’s nevertheless true that It’s Unlikely to Happen Here.
The Internet is a collection of smaller individual networks that trade information, each of which is known as an autonomous system (AS). These networks distribute information much like vendors distribute beer at a stadium: They pass it hand-over-hand until it reaches its destination. When a user of Network A wants to reach a service on Network B, Network A sends that user’s transmission to the edge of its network and then asks its neighboring networks “Which of you knows where Network B is?” Through the use of the Border Gateway Protocol (BGP), each of the neighboring networks tells Network A whether that neighbor knows where Network B is located and, if it does, how it would attempt to get information there. The neighboring networks answer these questions by referring to internal listings, known as BGP tables, which they periodically update when they learn of a new or better route. Network A chooses the neighboring network that reports having the best route to Network B and hands off the user’s data to that neighbor. This process repeats itself until the data is handed off to Network B, which in turn hands it to the service that the user was trying to reach.