Part of my job (fibre project engineer) is to oversee the building of fibre optic spine cables. Think of an 864 fibre cable snaking it’s way through town with various drop off nodes for local access networks to be built.
I also oversee the termination of the cable in the exchange, and the testing of the spine to make sure it’s within loss limits and that the right fibres are going to the right nodes.
I will often put a minor fault on in the exchange to see if the guys doing the testing pick up on the issue and report it back to me. Maybe a slightly dislodged connector, or fibre 275 crossed with fibre 276, for example.
Most of the time, the guys doing the testing will pickup on the issue and resolve it report it back to me. If it doesn’t get picked up on, I’ll make sure I keep a closer eye on the build crew.
*moot