I am a SI, delivered some identical sets of equipment to my customer. Each set consist of a 5-port unmanaged switch and 3 other devices. The 5-port unmanaged switch was uplinked to the customer's network thru only a single link. One of the device was a embedded PC control and would send data to the cusomer's central server. The other 2 devices would only communicate with that controller and occasionally have remote admin access.
I have to perform maintenance on the set of equipment. I have to plug-in my notebook to troubleshoot, or unplug and re-plug the devices for replacement. Sometimes. also need to power down and up the complete set of equipment, of course including the 5-port switch.
When I perform the maintenance job, my customer always compliant that there were many STP message generated. Can anyone explain why ?