Bandwidth

A great way to think about bandwidth is to liken it to a toll motorway. Bandwidth is the width of this motorway, which determines how much traffic there can be at any one time, and how fast that traffic can go.

Data cap

The data cap is how many vehicles in total there are allowed to travel at full-speed on this toll motorway at any given period of time (in this case, it would be per month). If this cap is reached, then all cars will be slowed to a fraction of the full-speed limit. For example, if the full-speed ability is 100 km/h, when the data cap is reached then all cars will have a maximum speed of 20 km/h.

The exception here is that if a data block is purchased, then the cars will be able to travel at their full speed again.