I am a member of the Citrix Consulting team, which leverages knowledge developed across the organization for various clients and industries. This knowledge is condensed into proven and continuously refined leading practices to assess, design, and deploy Citrix solutions, as well as to improve adoption and enhance security.

Video conferencing is a critical business tool and has become even more important as many employees shifted to remote work. Broad and rapid adoption of video conferencing tools by a remote workforce that’s also using desktop virtualization solutions in greater numbers created a perfect storm that put a lot of resource strain on virtualization platforms. While ICA can be tuned and optimized for audio/video delivery, the preferred solution is generally to redirect the processing of this traffic down the endpoint device. This has been the strategy behind many multimedia traffic optimizations over the years, including Flash, Windows Media, Skype, and now Teams.

Zoom developers have recognized the issue and developed their own solution consisting of two parts — a specialized version of the product called Zoom VDI Client (the application installed in Citrix VDA) and the Media (Zoom Thin Client) Plugin, which is deployed to the endpoint.

This blog builds on this post by my colleague Sagnik Datta, which provides an excellent overview of the Zoom VDI solution and its foundational technology, Citrix Channel SDK. This post, however, focuses on the particulars of implementing the Zoom VDI solution, derived from our experience configuring this product in the field.

The two elements communicate with the Zoom Cloud, as depicted on the diagram below.

The Infrastructure Impact

The standard Zoom client in a screen and video sharing session with minimal screen updates, such as demo of a business software, may easily consume two full CPU cores (50 percent of a quad-core VDA). The CPU consumption is even higher if generic drivers are used, so we recommend using optimized drivers.

The ICA traffic carrying the video and screen sharing data can also exceed 1 Mb/s of bandwidth, which is four times higher that of “normal” consumption (baselined around 250Kb) with a dual monitor setup at 1920 by 1080 resolution. The bandwidth consumption while sharing full screen high resolution 1080p video with optimized driver set is even greater — 3Mb just for the video alone. Generic driver bandwidth consumption may reach 10Mb — another reason to use optimized drivers. That traffic will have to traverse Citrix Gateway and various firewalls, potentially affecting performance and capacity of the environment. A sample of this from a test environment is shown below:

The participant in the same screen and video sharing meeting, who is using Zoom VDI, consumes a small fraction of the compute (15 percent of the overall CPU) and network (100Kb) resource utilization — a quarter of the CPU and a tenth of the network bandwidth as compared to the desktop client. Please note, these numbers may be affected by the type and configuration of the underlying host CPU.

Practical Implementation

The practical implementation of the solution starts with answering two questions — how and what.

HOW do I implement Zoom VDI? I would recommend following the phases below, based on the Citrix Consulting methodology:

  • Assess: Evaluate the enterprise needs and readiness for implementation of Zoom VDI, including required functionality, endpoint and VDA platforms, as well as the environment management capabilities.
  • Design: Develop engineering constructs leveraged by the solution, such as VDA and endpoint configurations, software distribution packages, and monitoring and alerting.
  • Deploy: Planning and execution, such as enabling the VDAs and endpoints to establish Zoom VDI sessions, and training for end users and support personnel.

Upon defining the HOW, we can proceed to the WHAT of the deployment. The implementation aspects for the key components of the deployment are summarized below:

Endpoint Devices

Zoom Plugin is supported on a number of endpoint platforms, namely Windows, IGEL, HP ThinPro OS, Ubuntu, and eLux.

By default, Zoom VDI will accommodate connections from unsupported endpoint platforms (such as MacOS) by emulating the standard Zoom Desktop client (with minor functional limitations, such as reduced default video resolution). The fallback mode is nearly as resource intensive as the Zoom Desktop client it emulates, so you should exercise careful planning and user education. To prevent excessive consumption of the VDA resources, a combination of technical and procedural elements could be leveraged, such as:

Software Distribution Toolkit Capabilities and Capacity

Zoom updates its software frequently, and keeping Zoom VDI and Thin Client Plugin on the same version/build yields the best performance and stability. Compatibility Mode, where the Zoom VDI and Thin Client Plugin are different versions/builds can be used on a short-term basis, but performance may be degraded.

The software distribution capabilities should be prepared and scaled to support at least monthly patches, while the ability to support a complete enterprise-wide version uplift overnight is highly desired.

Monitoring and Alerting

The following executables should be monitored for their CPU consumption, as their excessive use may signify misconfiguration between the Zoom VDI and Thin Client Plugin:

  • CptHost.exe
  • CtxAudioService.exe
  • ctxgfx.exe
  • dwm.exe
  • picaSvc2.exe
  • Zoom.exe

Appropriate exclusions for these processes are recommended for anti-virus software and Citrix Workspace Environment Management (WEM) CPU Optimization

In Summary

  • Zoom optimization functions to offload video and audio processing to the endpoint, which is critical to a successful, at-scale virtualized deployment and can provide significant reductions in VDA CPU usage and ICA bandwidth.
  • The Zoom optimization solution includes both VDA-side and endpoint-side software. You should validate that all planned endpoints are supported.
  • Consider using GPOs or WEM for management of the Zoom settings and customizations. If WEM is used, similar exclusions as those highlighted here for Skype, will need to be implemented for CPU spike protection.
  • Due to frequent updates, effective software distribution, monitoring, and alerting are critical to the success of the deployment.
  • And, as always, test, test, and test again.

If you have any questions, please leave them in the comments below or contact us at Citrix Consulting

Happy Zooming!