What is Loopback Test(s)?

Question

Software testing

There are problems with the Internet (speed dropped by 10 times). I ran tests with the Intel driver and there is such an error. What does she mean? What is Loopback Test(s)?

Answer 1

This error means that in order to test the adapter (which most likely has nothing to do with it), you need to make a special loopback cable, which you can insert into the connector of the tested card.
(from here, but in other places there is also a wiring https://www.juniper.net/documentation/en_US/junos/...
If there are problems with the Internet, then call the provider for debriefing.

Answer 2

loopback test in network cards is a test in which the transmitter is connected to the receiver inside the network card (internal loopback - everything except the physical interface is tested) or outside (external loopback - everything is tested).