Internet Speed Monitor - part 2 - basic SW

 Let see in more details how to put together the basic  internet speed monitor contraption.
This article discuss setting up the Raspberry Pi.

Internet Speed Monitor - part 1 - specifications

Recently my connection with the provider for internet, has some problems.
Running some speed tests from different computers shows really erratic results.

I should have something about 12 Mbit/s downstream and 2 Mbit/s upstream, some tests shows up to 15 Mbit/s-1.5 Mbit/s, others down to 1 Mbit/s-0.25Mbit/s

Not easy to pin point the nature of the problem.