Bandwidth

Bandwidth

1. Bandwidth is how much data can be transmitted along a communications channel in a given amount of time

2. Bandwidth = volume of data / time

   • e.g. how long would it take to download a 640MB(megabyte) movie on an 8Mbps (megabits per second) internet connection
     • 640 x 8 --------- = 8 8

3. Bandwidth is given in bits per second (bps). This is the number of bits can be transferred each second.

   • Bps is bytes per second 1 byte = 8 bits

4. The Impact of bandwidth

   • Bandwidth depends on the activities; some activities using the internet that requires alot of bandwidth to work.
   • Bandwidth affects the time it takes to download and upload files.
   • 2 ways to watch a movie online;
     • Download; wait for it to download it completely
     • Streaming; you can download some and start watching (progressive download). hoping download will continue just ahead what you are watching.
   • Bandwidth affects downloading because of time it takes.
   • Large bandwidth = reduce the time to download a file
   • However, time taken for it to download doesnt affect the viewing/listening of file once its downloaded
   • effect of too low bandwidth on streaming = video might stop while more is downloaded. the sound and picture get "out of sync" or the picture pixelate
   • bandwidth has implications on time-dependent applications, e.g. video conferencing, which needs high bandwidth to display moving images.