Use RDP Multipath to improve connection reliability to Azure Virtual Desktop

Remote Desktop Protocol (RDP) Multipath improves session stability by continuously monitoring multiple network paths and dynamically selecting the most reliable one. This intelligent switching mechanism helps reduce the likelihood of disconnections and contributes to a smoother and more consistent user experience across different network conditions.

It offers several key benefits:

• Seamless integration: No configuration changes are needed beyond ensuring your environment supports RDP Shortpath.

• Intelligent path management: ICE discovers and evaluates multiple Remote Desktop Protocol (RDP) Shortpath routes using User Datagram Protocol (UDP) over STUN (Simple Traversal Underneath NAT) and TURN (Traversal Using Relays around NAT) protocols.

• Enhanced reliability: Backup paths remain on standby. If the active path becomes unstable or fails, RDP Multipath automatically switches to the next best path, reducing session drops and interruptions.

RDP Multipath uses multiple network paths to improve connection reliability. These paths can include combinations of UDP-based STUN or TURN connections when UDP connectivity is available, along with redundant TCP-based Reverse Connect paths established using Rendezvous. If the main transport path becomes degraded or fails, the system automatically switches to a backup available UDP or TCP transport path. If all paths are lost—such as during a network outage—the system attempts to reconnect once network connectivity is restored. 

The following diagram illustrates how RDP Multipath works with Azure Virtual Desktop. In this user scenario, the primary active transport path is UDP via STUN, supplemented by redundant UDP connections through a TURN server.

When UDP‑based RDP Shortpath connectivity is available, UDP remains the preferred transport protocol for optimal performance and reliability. In addition to maintaining redundant UDP paths, Azure Virtual Desktop can establish redundant TCP standby transport paths to improve overall session resiliency.

Availability

RDP Multipath capabilities are available across the following Azure environments:

Environment	Multiple UDP transport paths	Redundant TCP transport paths
Azure public cloud	Generally available	Generally available
Azure Government	Generally available	Phased rollout started

Note

RDP Multipath with redundant TCP is being enabled through a phased GA rollout in Azure Government. Until the rollout is complete, customers can try the feature by enabling their host pool for the validation ring.

Prerequisites

RDP Multipath works automatically when the following prerequisites are met:

• Microsoft recommends configuring RDP Shortpath as the primary transport protocol to maximize the resiliency benefits of RDP Multipath. For more information, see Configure RDP Shortpath.

• Windows App for Windows:

  • Connections must be from a local Windows device using Windows App, version 2.0.559.0 or later, which is the minimum supported version for RDP Multipath. This version enables RDP Multipath with multiple UDP transport paths.

  • To take advantage of the latest RDP Multipath enhancements, including support for multiple UDP transport paths and redundant TCP transport paths, connections must use Windows App Version 2.0.1069.0 or later

• Windows App for macOS Beta: RDP Multipath with multiple UDP transport paths is supported with Windows App for macOS Beta version 11.3.8 (3048).

• Other platforms aren't currently supported.

Required network endpoints for RDP transport

To support RDP connectivity using UDP-based RDP Shortpath and RDP Multipath, as well as TCP-based connections over Reverse Connect, ensure outbound connectivity to the following endpoints:

Azure cloud

#	RDP method	FQDN	IP address	Protocol/port	Description
1	TCP-based RDP	*.wvd.microsoft.com	40.64.144.0/20	TCP 443	TCP-based RDP connection. The initial connection to every session host or Cloud PC uses this connection.
2	UDP-based RDP via TURN	N/A	51.5.0.0/16	UDP 3478	Relayed UDP-based RDP connection using TURN servers. This method works when direct connectivity isn't possible.
3	UDP-based RDP using STUN	N/A	51.5.0.0/16	UDP 1024-65535 Default: 49152-65535	Direct one-to-one UDP connection between the user device and the session host or Cloud PC.

Azure for US Government

Important

RDP Shortpath connectivity through the endpoints listed in this tab is currently available in public preview for Azure Government. Availability is limited to designated validation rings during the preview.

#	RDP method	FQDN	IP address	Protocol/port	Description
1	TCP-based RDP	N/A	20.159.80.0/24	TCP 443	TCP-based RDP connection. The initial connection to every session host or Cloud PC uses this connection.
2	UDP-based RDP via TURN	N/A	20.140.236.0/22	UDP 3478	Relayed UDP-based RDP connection using TURN servers. Available in the validation ring.
3	UDP-based RDP using STUN	N/A	20.140.236.0/22	UDP 1024-65535 Default: 49152-65535	Direct one-to-one UDP connection between the user device and the session host. Available in the validation ring.

Port scaling considerations

When using RDP Multipath, customers should plan firewall and network capacity with per‑user port scaling in mind.

Each active user session can establish up to five outbound transport paths:

• Up to three UDP ports for UDP‑based RDP Shortpath and Multipath connections (for example, primary and redundant UDP paths discovered through STUN or TURN).

• Up to two TCP ports for TCP‑based RDP connections over Reverse Connect, including redundant TCP transport paths when available.

Ensure that firewall rules, NAT capacity, and port exhaustion limits are configured to accommodate the expected number of concurrent user sessions and their associated transport paths at scale.

Important

Microsoft recommends using Windows App version 2.0.1069.0 or later and configuring RDP Shortpath as the primary transport protocol for the best RDP Multipath experience. With Windows App version 2.0.559.0 or later, users benefit from RDP Multipath with multiple UDP transport paths. With Windows App version 2.0.1069.0 or later, users gain the additional resiliency benefits of redundant TCP transport paths. If UDP connectivity is unavailable or restricted by network policy, RDP Multipath can continue to provide resiliency through redundant TCP transport paths.

Verify RDP Multipath connectivity

There are two ways to verify that RDP Multipath is being used for a connection:

• Users can check the connection status of a remote session from the connection bar, which shows RDP Multipath is enabled, as shown in the following example screenshot:

  

• Azure Virtual Desktop administrators can view connection reliability information in Azure Virtual Desktop Insights. For more information, see the connection reliability use case for Azure Virtual Desktop Insights.

Related content

To learn more about RDP Shortpath, see RDP Shortpath for Azure Virtual Desktop.