What does UPSTR stand for?

Upstream

The inlet side of an instrument, a pump, valve, etc. The exploration, production, and transportation of oil and gas. The passage ahead of a device, normally at the inlet of direction of flow.The location of a server in relation to another server. The direction in which data moves from an individual computer to the remote network. With certain communications technologies, such as ADSL, cable modems, and high-speed 56-Kbps modems, data flows upstream more slowly than downstream.