Bandwidth is the ammount of data that can go through media at one time. For example, a water pipe would the media and the water is the data. If the pipe were to be bigger there would be more water (data) going through it. If it were smaller, there would be less data going through it. The problem is that you can’t send the whole thing at once because it would be too big. So what happens is that the data splits down into chunks called packets and then is transferred through to it’s destination. To test your bandwidth visit this web page : http://www.bandwidthplace.com/