Bandwidth is the amount of data transmitted over a period of time.  Internet Speed is measured by how quickly you can download or upload content in a second.  Go to speedtest.net.

Internet speed is like your shower head in your bathroom.  If you turn on the knob a little, it will take you forever to rinse off.  I you turn on the knob full blast, it will take a few seconds to rinse off.

Bandwidth is the amount of data transmitted over a period of time.  Like in  the shower analogy, if your pipe is smaller than your shower head pipe, you are not going to have much pressure.  If your pipe is larger than your shower head pipe, then you will have greater pressure.  More water over a period of time.

Most POS companies recommend a minimum of 15Mbps for download and 5Mbps for uploads.

Bandwidth information-Ping 13  Internet Speed-Download and Upload   Internet Service Provider-Xfinity