Using QoS DSCP Marking

Quality of Service (QoS) DSCP Marking determines traffic classification for network data. This can be used to determine which network traffic requires higher bandwidth, has a higher priority, and is more likely to drop packets.

The default Zoom DSCP marking values are 56 for audio, 40 for video, and 40 for screen sharing. You can update audio and video values to allow a network administrator to adjust the priority for Zoom traffic on their network.

This article covers:

• How to enable DSCP in Zoom
• How to set DSCP Marking through Group Policy

Prerequisites for using QoS DSCP Marking

• Zoom desktop client
  • Windows: global minimum version or higher
  • macOS: global minimum version or higher
• Zoom Rooms
  • Windows: global minimum version or higher
  • Appliances: global minimum version or higher

How to enable DSCP marking

To enable DSCP marking for all users in the account:

1. Sign in to the Zoom web portal as an admin with the privilege to edit account settings.
2. In the navigation panel, click Account Management then Account Settings.
3. Click the Meeting tab.
4. Under In Meeting (Advanced), verify that DSCP marking is enabled.
5. If the setting is disabled, click the toggle to enable it. If a verification dialog displays, click Turn On to verify the change.
6. (Optional) If you want to make this setting mandatory for all users in your account, click the lock icon , and then click Lock to confirm the setting.
7. Update and enter Audio and Video values.
8. Click Save.

How to set DSCP marking through Group Policy

Due to changes by Microsoft, the Zoom client or Zoom Rooms app must be run as an administrator to be able to utilize DSCP marking. However, both applications can be tracked by Group Policy QoS policies as an alternative method, if the apps are not running with administrative privileges. 

To set DSCP Marking through Group Policy:

1. Deploy the Zoom MSI client or Zoom Rooms MSI app with Independent Data Ports enabled either by: 
   • Adding the variable to the installation string, EnableIndependentDataPort=1.
   • Adding the variable to the Group Policy Object for the Zoom app, “EnableIndependentDataPort”=dword:00000001.
     Note: For more information on mass-deploying the Zoom client with this variable enabled. 
2. Open Group Policy Management Console (GPMC) and edit your desired Group Policy Object (GPO).
3. Click Create new policy....
4. Name the policy.
5. Ensure that the Specify DSCP Value check box is selected, then set the desired DSCP value for Zoom traffic.
6. Click Next.
7. Under Only applications with this executable name, set the executable name to Zoom.exe or ZoomRooms.exe, based on which app you are using. 
8. Click Next.
9. Leave the default IP address settings and click Next.
10. Set the protocol to TCP and UDP.
11. Leave the default port settings and click Finish.
12. Deploy the new Group Policy and reboot the devices it is applied to.
    Once the Zoom Windows client is in a meeting, ensure that you see marked packets, which are being sent from the client to the Zoom meeting server.