Cryptonomicon

by Neal Stephenson

The Internet poses another problem for telcos by being asymmetrical. Imagine you are running an international telecom company in Japan. Everything you’ve ever done, since TPC-1 came into Ninomiya in ‘64, has been predicated on circuits. Circuits are the basic unit you buy and sell — they are to you what cars are to a Cadillac dealership. A circuit, by definition, is symmetrical. It consists of an equal amount of bandwidth in each direction — since most phone conversations, on average, entail both parties talking about the same amount. A circuit between Japan and the United States is something that enables data to be sent from Japan to the US, and from the US to Japan, at the same rate — the same bandwidth. In order to get your hands on a circuit, you cut a deal with a company in the States. This deal is called a correspondent agreement.