From the provider to the customer. Downloading files and Web pages from the Internet is the downstream side. The upstream is from the customer to the provider (requesting a Web page, sending email, etc.). In cable TV, downstream signals are the network, movie and sports channels transmitted to the customer. However, if the cable provider offers video-on-demand or Internet access, the cable also has an upstream.
Internet access speeds are typically not symmetrical, with the downstream rate being considerably faster than the upstream. The slower upstream prevents users from operating websites. For fast upstream Internet connections, the customer can sign a business-oriented service agreement, if available, or use specialized providers that accommodate datacenters and high-speed servers. See download
and download vs. upload