Symmetric vs. Asymmetric Internet

Circuit Bandwidth

Every Internet connection has two bandwidth specifications, one for the downstream direction and another for the upstream direction.

When purchasing Internet for your business, it is important to realize that every Internet connection has a distinct speed for each direction of data flow. Data can flow upstream or downstream.

Data Direction	Data Transfer Operation is Called	Description	Example
Downstream	Download	When data is transmitted from the Internet to your network	Watching Netflix
Upstream	Upload	When data is transmitted from your network to the Internet	Performing a cloud backup of your files

When an Internet circuit has a speed that is the same in both the downstream and upstream directions, the circuit is called symmetric. When these speeds differ, the circuit is called asymmetric.

Watch Out For Misleading Marketing

Sometimes an ISP will only advertise the downstream bandwidth of an asymmetric Internet circuit, obscuring a low upstream bandwidth. For a business, upstream bandwidth can be just as important.

Almost all enterprise-class fiber Internet circuits are symmetric circuits. Symmetric circuits are superior to asymmetric circuits because they do not handicap the flow of data from your business to the Internet.

Cable modem and DSL-based connections will often have upstream bandwidth speeds of less than 10% of the advertised downstream speeds. This can cause operations like cloud backups to consume all upstream bandwidth and fail to complete in a timely manner. And when upstream bandwidth is saturated, downstream performance will also degrade, as downstream data transmission still requires upstream communications.