Bandwidth

Bandwidth is the amount of data that moves along transmission lines or circuits at a given speed. For example, the time it takes a personal computer to load a word-processing program is dependent upon bandwidth, as is the load time for a World Wide Web page. Transmission speed is expressed either in bits-per-second (bps) for digital devices such as modems, or cycles-per-second, more commonly known as hertz (Hz), for analog devices such as microprocessors.

When bandwidth is inadequate for the function being performed, the slowdown that occurs is called a bottleneck. Bottlenecks can reduce either the transmission speed of data between components of a computer or within both local area and wide area networks. To circumvent this problem, personal computer manufacturers have developed machines with much faster busses—the circuits that actually carry data throughout a computer—such as the 40 mHz VL-bus and the 66 mHz AGP. Similarly, increased Internet traffic, and the more sophisticated graphical applications available on the World Wide Web, have prompted networking technology firms to develop devices like Gigabit Ethernet, Fast Token Rings, and T1 lines as a means of offering increased bandwidth rates to businesses and other institutions, as well as to individuals.