Citrix Virtual Apps and Desktops

Adaptive transport

August 22, 2024

Contributed by:

C C

Adaptive Transport is a mechanism in Citrix Virtual Apps and Desktops that allows establishing connections for HDX sessions using a preferred transport protocol while providing a fallback to TCP if connectivity with the preferred protocol is unavailable.

The following transport protocols are supported:

Enlightened Data Transport (EDT)
Transmission Control Protocol (TCP)

Configuration

Adaptive Transport is enabled by default. You can configure Adaptive Transport to operate in the following modes:

Preferred: (Default) The client attempts to connect with the preferred protocol and falls back to TCP if connectivity with the preferred protocol is unavailable.
Diagnostic mode: The client only attempts to connect using the preferred protocol. Fall back to TCP is disabled.
Off: The client only attempts to connect using TCP.

How it works

When Adaptive Transport is set to Preferred, the client attempts to connect to the session with both the preferred protocol and TCP in parallel. This allows optimizing the connection time if it’s not possible to connect with the preferred protocol and the client must fall back to using TCP. If the connection is established using TCP, the client attempts to connect with the preferred protocol in the background every five minutes.

When Adaptive Transport is set to Diagnostic mode, the client connects to the session only with the preferred protocol. If the client is unable to establish a connection using the preferred protocol, it doesn’t fall back to using TCP, and the connection fails.

When Adaptive Transport is set to Off, Adaptive Transport is disabled, and the client connects to the session using TCP only.

Network stack

Adaptive transport

System requirements

The following are the requirements for using Adaptive Transport and EDT:

Control plane
- Citrix DaaS (formerly Citrix Virtual Apps and Desktops service)
- Citrix Virtual Apps and Desktops: currently supported version
Virtual Delivery Agent
- Windows: currently supported version (2402 or later is recommended)
- Linux: currently supported version (2402 or later is recommended)
Citrix Workspace app
- Windows: currently supported version (2402 or later is recommended)
- Linux: currently supported version (2402 or later is recommended)
- Mac: currently supported version (2402 or later is recommended)
- iOS: latest version available in the Apple App Store
- Android: latest version available in Google Play
Citrix NetScaler Gateway
- 14.1.12.30 or later (recommended)
- 13.1.17.42 or later (13.1-52.19 or later recommended)

Note:

For details on Linux VDA, see the Linux Virtual Delivery Agent documentation.

Network requirements

The following sections are the network requirements for using EDT with Adaptive Transport:

Session hosts

If your session hosts have a firewall such as Windows Defender Firewall, you must allow the following inbound traffic for internal connections.

Description	Source	Protocol	Port
Internal connection - Session Reliability enabled	Client	UDP	2598
Internal connection - Session Reliability disabled			1494
Internal connection - HDX Direct or VDA SSL			443

Note:

The VDA installer adds the appropriate inbound rules to the Windows Defender Firewall. If you use a different firewall, you must add the rules above.

Internal network

The following table depicts the firewall rules required for using EDT in your network:

Description	Protocol	Source	Destination	Destination port
Direct internal connection - Session Reliability enabled	UDP	Client network	VDA network	2598
Direct internal connection - Session Reliability disabled				1494
Direct internal connection - HDX Direct or VDA SSL				443
NetScaler Gateway		NetScaler SNIP		2598
NetScaler Gateway - VDA SSL		NetScaler SNIP		443

Note:

If you are using Citrix Gateway Service, you must enable Rendezvous to use EDT as your transport protocol. See the Rendezvous documentation for system and network requirements.

Client network

The following table outlines the connectivity requirements for client devices:

Description	Protocol	Source	Destination	Destination port
Internal connection - Session Reliability enabled	UDP	Client IP	VDA network	2598
Internal connection - Session Reliability disabled				1494
Internal connection - HDX Direct or SSL VDA				443
External connection - NetScaler Gateway			NetScaler Gateway public IP address	443
External connection - Citrix Gateway Service			Citrix Gateway Service	443

Note:

If you are using Citrix Gateway Service, clients must be able to reach https://*.*.nssvc.net. If you can’t allow all subdomains using https://*.*.nssvc.net, you can use https://*.c.nssvc.net and https://*.g.nssvc.net instead. For more information, see Knowledge Center article CTX270584.

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Adaptive transport

August 22, 2024

Contributed by:

C C

August 22, 2024

Contributed by:

C C

Adaptive transport

Configuration

How it works

System requirements

Network requirements

Session hosts

Internal network

Client network

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