I'm going to take off my MySQL DBA hat and put on my network admin hat for a moment and talk about Quality of Service (QoS). This is largely in the scope of using QoS for residential and small office setups where you largely see non-symmetric connections, often with fairly low upload speeds, at least here in the US. My own home connection is a U-Verse FTTP install that gives me 50mbps down and a measly 5mbps up.
To start, maybe it's best to play out a common scenario. You're trying to get some...