Data transfer where upstream and downstream data flow occurs at different speeds, usually a higher rate of speed downstream, and a slower rate upstream. Reflective of typical end-user Internet usage patterns, where more data is received than sent, and no servers (such as web server) are in operation.
Providing differing bandwidth in different directions. 56 K modems are asymmetrical: they offer a maximum speed of 56K for downloading, but only 28.8K or 33.6K for uploading.
Offering different data rates in the upstream and downstream directions, where upstream is the direction from the end-user to the network, and downstream is the direction from the network to the user.