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# 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. |  |



### Add Interface

To add an interface:

* Click the **Add** button

The interface dialog opens.

* Select an **Interface** from the list

* Click **OK**

* Enable other settings as needed:
 * Turn QoS on with the **Enable QoS** slider
 * Select an available **Classification Group**
 * Turn QoS on with the **Limit Download Speed** slider
  * Enter a speed value (kbps)
 * Turn QoS on with the **Limit Upload Speed** slider
  * Enter a speed value (kbps)

* Click **Apply**