Symmetry in a networking sense refers to the ratio of upstream to downstream traffic that can be supported on a given link type.
The majority of consumer data services have historically been delivered as asymmetric services since most traffic appears in the downstream direction, such as downloading of a mail, files, video etc, and only minimal traffic is sent upstream to acknowledge that the file or data has been received.
Larger businesses have different needs such as being able to send large quantities of email out, or hosting a webserver or remote-access services that would require higher uplink bandwidths.
The Unwired business network provides both asymmetric and symmetric services.