In short, bandwidth refers to your network’s capacity to handle Internet traffic.

Bandwidth describes the maximum data transfer rate of a network or Internet connection. It measures how much data can be sent over a specific connection in a given amount of time.
Another way to think of bandwidth is as a pipe. The more bandwidth you have, the bigger the pipe; the bigger the pipe, the more information can travel down the pipe at once. 

With VoIP traffic, we recommend 100k of bandwidth per phone. Other devices, such as computers, printers and credit card machines also utilize bandwidth.