Meetings optimization for VDI in Zoom

This post was most recently updated on July 23rd, 2022

There are times when multiple users will be using a VDI server at the same time because it is a shared hardware resource. It is generally true that VDI hardware – which can be used to support multiple virtual desktops – cannot support the additional processing demands of video conferencing in addition to other requirements of the software.

In order to address this issue, Zoom VDI Client and plugin remove most of the media-processing workloads from the VDI server, and instead direct the tasks to the plugin, which in turn processes the media on the local machine, using the CPU and RAM resources of the plugin. In order to ensure that the user experience is optimized, Zoom sends independent data streams to both the VDI Client, as well as the plugin, allowing them to concentrate on the things they do best.

In this article, we will cover the following topics:

  • VDI meeting optimization
    • Direct Optimization
  • Alternative connection modes
    • UDP/Channel Optimization
    • Fallback Mode
  • Supported meeting optimization clients

Prerequisites for Zoom Meetings optimization

  • There are many organizations that utilize Citrix XenDesktop or VMware Horizon servers for publishing their desktops, or those that use Windows Remote Desktop.
  • AVD Client for Citrix Workspace, VMware Horizon for Windows or Citrix Workspace for VMWare Horizons
    Note: In the Microsoft store, you will not be able to download the Citrix Workspace app.

VDI meeting optimization

In order to achieve this optimized experience, the VDI Client renders a placeholder that basically encapsulates the meeting content and the meeting toolbar buttons of the Zoom meeting in order to create an empty placeholder of the meeting. Through its direct connection to the Zoom meeting, the VDI Client also maintains in-meeting data such as the participation list, as well as a screen-sharing session of the local user’s desktop, so that he or she can participate in the meeting.

Direct Optimization

A similar approach is taken when the plugin is integrated with the Direct Optimization experience where it assists the VDI Client by doing the other half of what the VDI Client should be doing. A direct connection to Zoom is also provided so that the plugin can receive meeting video, audio, and content from the Zoom meeting. These elements are then layered on top of the placeholder image for meeting content on the VDI Client.

With the VDI Client and the plugin, the VDI meets are rendered as layers, with the plugin’s media superimposed over the VDI client’s Zoom placeholder, creating an immersive, synchronized experience. By using the existing virtual channel provided by the VDI software provider, the plugin and the VDI Client coordinate their efforts.

In Zoom Cloud, two data streams are maintained for the VDI desktop as well as the plugin, so that both can be accessed simultaneously. The following is what happens when you are working in Direct Optimized mode:

  • This plugin receives streaming data streams from the cloud to be used for inbound content, such as video, audio, and social media.
  • In the VDI desktop, all the meeting data is received in the Zoom Client placeholder as the general meeting data, such as participant information, and the VDI desktop is shown that information along with any local screen-sharing content that has been uploaded.
  • Through the VDI vendor’s virtual connection, both the plugin and the VDI desktop communicate with one another, signaling where the on-screen media should be placed and rendered between the two layers, using the vendor’s virtual connection to exchange information.

Alternative connection modes

As part of the Zoom meeting infrastructure, the VDI Client supports three different modes of connection. Direct Optimized, the most commonly used mode of Zoom for desktop users, involves both the VDI Client and the Zoom plugin establishing a unique connection to Zoom and rendering their own portions of a Zoom meeting independently for a seamless experience.

There are also a number of other connection modes that the VDI Client can use – UDP/Channel Optimized, and Fallback Mode – to suit individual workflow requirements or security concerns. There are a number of significant differences between the different modes of operation as shown in the following table.

Media  offloading Plugin direct cloud access
Direct Optimized
UDP/Channel Optimized
Fallback Mode

UDP/Channel Optimization

There is a similar process to Direct Optimization in regards to UDP and Channel Optimization, where the plugin renders the meeting media even though the network path is a different one. There are a number of things that happen in this mode, including:

  • In order for meeting media to be delivered to the VDI server from Zoom Cloud, first it must be delivered to the VDI server.
  • When a UDP connection cannot be established, the VDI server transfers the media to the plugin through an existing virtual channel on the VDI server, or over the out of band connection if a UDP connection cannot be established.

Unless your organization is able to allow direct Internet access for thin clients (or other remote devices), it may be more suitable for using this method, although the additional routing can result in a less optimal experience than Direct Optimization.

Fallback Mode

When Fallback Mode is enabled, Zoom clients will run directly on the VDI server and be provided with an unoptimized VDI experience. Only the VDI Client communicates with Zoom in this configuration because there is no media optimization or plugin that is being used.

As a result of the processing that needs to be performed by VDI servers, this method is not the most preferred option. A Fallback Mode can result in VDI sluggishness, choppy video, distorted audio, among a number of other quality issues, when the software is running in Fallback Mode. If plugins are not available for use or if this is not an option as a last resort, it is recommended that this should not be used.

Note: To maintain server performance, it is recommended that Fallback Mode is avoided whenever possible.

Supported meeting optimization clients

Here is a list of the virtual desktop agents and operating systems that are currently supported for the optimization of meetings using virtual desktop agents.

Citrix VMware Azure Virtual Desktop
Ubuntu / Debian
HP ThinPro OS
Centos / Redhat / Fedora
Dell Wyse