RDP Multipath Explained: Boost Azure Virtual Desktop Stability & Performance

Microsoft has recently announced the general availability of RDP Multipath for Azure Virtual Desktop (AVD), and it’s a significant improvement for connection stability and performance. If you’ve ever dealt with unexpected AVD disconnects or unstable connections, this feature can be a game changer.

In this article, we’ll review what RDP Multipath is, how it works, the features of the PowerShell script used to enable or disable it, and the steps to deploy that script through a Custom Script Extension in Azure.

Overview: What is RDP Multipath and How It Works

RDP Multipath builds on top of RDP Shortpath to create more resilient connections between the AVD client and the session host. Traditionally, AVD connections start with a TCP Reverse Connect transport through the gateway service. If RDP Shortpath is enabled and UDP connectivity is available, the connection can switch to a more efficient UDP path—either direct or via an AVD TURN relay.

With RDP Multipath, Interactive Connectivity Establishment (ICE) continues to monitor all available connections during the session. If the active connection becomes unstable or drops, the session seamlessly switches to another available connection path without requiring user reconnection.

Key points:

• RDP Multipath works with RDP Shortpath enabled and UDP unblocked on both client and session host.
• Requires Windows App version 2.0.559 or newer, or RDP client version 1.2.6353 or newer.
• Currently supported only on Windows clients.
• Enabled by default as the feature rolls out via AVD Agent updates.
• Can be manually enabled or disabled via registry settings for early adoption or troubleshooting.

The provided PowerShell script makes it simple to enable (opt-in) or disable (opt-out) of RDP Multipath on a session host. It can be run locally or deployed to multiple hosts using Azure automation tools.

Script highlights:

• Parameter-driven: Accepts an input parameter to enable or disable RDP Multipath.
• Registry management: Checks for the required registry key and creates it if missing.
• Value setting: Sets the registry value to 100 (enable) or 0 (disable) depending on the parameter.
• Error handling: Includes basic error messages for troubleshooting.
• Logging: Adds comment lines to track script actions for easier review.

This script can be deployed manually or as part of a Custom Script Extension for larger host pools.

If you need to enable or disable RDP Multipath on multiple session hosts, the Azure Custom Script Extension is a convenient deployment method. Here’s how to do it:

1. Prepare the Script File
   • Save the PowerShell script as a .ps1 file.
   • Upload the script to a location accessible by your VMs, such as an Azure Storage account or GitHub repository. Save to an Azure Storage Blob container if deploying through the portal.
2. Open the Azure Portal
   • Navigate to the Virtual Machine representing your AVD session host.
3. Go to Extensions
   • In the left-hand menu, select Extensions + applications.
   • Click + Add to create a new extension.
4. Select Custom Script Extension
   • Choose Custom Script Extension from the list.
   • Click Next or Create depending on the portal view.
5. Configure the Extension
   • Provide the script location (URL or Azure Storage path).
   • If you are disabling RDP Multipath, modify the script parameter or default value before deployment.
6. Deploy the Extension
   • Click Review + Create to confirm and deploy.
   • Wait for the deployment to complete.
7. Repeat for All Hosts
   • Run the extension on each host in the pool, or temporarily set other hosts to drain mode before deployment.

RDP Multipath is a major step forward for Azure Virtual Desktop reliability, reducing session drops and improving user experience. Whether you want to enable it early or disable it for troubleshooting, the combination of a simple PowerShell script and Azure’s Custom Script Extension makes deployment straightforward across your environment.

By implementing RDP Multipath now, you can give your users a smoother, more stable AVD experience—and spend less time managing reconnection issues.

Links

A Beginner’s Guide to the AZ-900
https://www.udemy.com/course/beginners-guide-az-900/?referralCode=C74C266B74E837F86969

Zero to Hero with Azure Virtual Desktop
https://www.udemy.com/course/zero-to-hero-with-windows-virtual-desktop/?referralCode=B2FE49E6FCEE7A7EA8D4

Hybrid Identity with Windows AD and Azure AD
https://www.udemy.com/course/hybrid-identity-and-azure-active-directory/?referralCode=7F62C4C6FD05C73ACCC3

Windows 365 Enterprise and Intune Management
https://www.udemy.com/course/windows-365-enterprise-and-intune-management/?referralCode=4A1ED105341D0AA20D2E

Link to the code on GitHub
https://github.com/tsrob50/CiraltosTools

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