BGP

Chapter 1. The Internet, Routing, and BGP

One of the many remarkable qualities of the Internet is that it has scaled so well to its current size. This doesn’t mean that nothing has changed since the early days of the ARPANET in 1969. The opposite is true: our current TCP and IP protocols weren’t constructed until the late 1970s. Since that time, TCP/IP has become the predominant networking protocol for just about every kind of digital communication.

The story goes that the Internet—or rather the ARPANET, which is regarded as the origin of today’s Internet—was invented by the military as a network that could withstand a nuclear attack. That isn’t how it actually happened. In the early 1960s, Paul Baran, a researcher for the RAND Corporation, wrote a number of memoranda proposing a digital communications network for military use that could still function after sustaining heavy damage from an enemy attack.^[2] Using simulations, Baran proved that a network with only three or four times as many connections as the minimum required to operate comes close to the theoretical maximum possible robustness. This of course implies that the network adapts when connections fail, something the telephone network and the simple digital connections of that time couldn’t do, because every connection was manually configured. Baran incorporated numerous revolutionary concepts into his proposed network: packet switching, adaptive routing, the use of digital circuits to carry voice communication, and encryption ...