{{indexmenu_n>20}} # Interface The **interface** tab lets you select interfaces and configure [Quality of Service](/glossary/q/qos) profiles for them. ## Overview At the top of the page is a list of selectable interfaces. When a particular interface is selected, details about it is shown in the configuration section. ^ Item ^ Description ^ ^ | Enable QoS | Turn the [Quality of Service](/glossary/q/qos) on for the interface. | | | Classification Group | [Classification group](/glossary/q/qos_group) to use for the interface. | | **Note:** You need to [create the group](../group/start) for it to be available in the list. | | Calculate Overhead | Include [overhead](/glossary/o/overhead) in the packet calculations for [shaping](/glossary/s/shaping) and [policing](/glossary/p/policing). | |  | Limit Download Speed | Restrict the network speed *to* clients. | | | Limit Upload Speed | Restrict the network speed *from* clients. | |