1. The location of a server in relation to another server. Compare downstream (definition 1).
2. 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. For example, a 56-Kbps modem can deliver data at a 56-Kbps maximum only downstream; upstream, it delivers data at either 28.8 or 33.6 Kbps. Compare downstream2 (definition 2).

Against the current

The direction in which information is delivered from a client to a (Web) server. Compare downstream1.

In the direction against a stream's current.