|  | 1.5 | Digital Bandwidth
| 1.5.2 | Three analogies to describe digital bandwidth

Bandwidth is a very important element of networking, yet it can be rather abstract and difficult to understand. Following are three analogies that may help you picture what bandwidth is: [Place the cursor of your mouse over the numbers in the animation to the left to view different bandwidth analogies.]

1. Bandwidth is like the width of a pipe.

> Think of the network of pipes that brings water to your home and carries sewage away from it. Those pipes have different diameters -- the city's main water pipe may be 2 meters in diameter, whereas the kitchen faucet may be 2 centimeters. The width of the pipe measures the water-carrying capacity of the pipe. In this analogy the water is like information and the width of the pipe is like bandwidth. In fact, many networking experts will talk in terms of "putting in bigger pipes" meaning more bandwidth; that is, more information-carrying capacity.

2. Bandwidth is like the number of lanes on a highway.

> Think about a network of roads that serves your city or town. There may be eight-lane highways, with exits onto 2- and 3-lane roads, which may then lead to 2-lane undivided streets, and eventually to your driveway. In this analogy, the number of lanes is like the bandwidth, and the number of cars is like the amount of information that can be carried.

3. Bandwidth is like the quality of sound in an audio system.

> The sound is the information, and the quality of the sounds that you hear is the bandwidth. If you were asked to rank your preferences on how you would rather hear your favorite song - over the telephone, on an AM radio, on an FM radio, or on a CD-ROM – you would probably make the CD your first preference, then FM radio, AM radio, and finally telephone. The actual analog bandwidths for these are, respectively, 20 KHz, 15 KHz, 5 KHz, and 3 KHz.

Keep in mind that the true, actual meaning of bandwidth, in our context, is the maximum number of bits that can theoretically pass through a given area of space in specified amount of time (under the given conditions). The analogies we've used are only used here to make it easier to understand the concept of bandwidth.