I have been looking into an issue with a customers LAN investigating slow throughput.
A couple of things I have learned and have confused me on how to determine the actual speed of a connection between a PC and its switch/router...
When I throttle the port that a PC is connected, to 512Kb/s using QOS, the PC still says the link speed is 1Gb/s
When I set the the port speed to say 10Mb/s Windows says it is connected to a 10Mb/s link.
The difference suggests Windows or the NIC, asks the Switch for the link speed and doesn't actually measure the line speed.
Why am i looking at this?
I have always been curious about the impact poorly deployed cabling has on actual LAN performance. If for example a cable ran past a device that induced some sort of interference that slowed traffic across the cable, then Windows may be oblivious to it, and all the testing at switch and device level may not highlight the fact that the cable run from the outlet to the patch panel is the problem.
Your collective thoughts/knowledge and understanding apprecaited