Citrix Adaptive Transport

Citrix Adaptive Transport

Introduction to latest CVAD release

Adaptive transport is a data transport mechanism for Citrix Virtual Apps and Desktops. It is faster, can scale, improves application interactivity, and is more interactive on challenging long-haul WAN and internet connections. Adaptive transport maintains high server scalability and efficient use of bandwidth. By using adaptive transport, ICA virtual channels automatically respond to changing network conditions. They intelligently switch the underlying protocol between the Citrix protocol called Enlightened Data Transport (EDT) and TCP to deliver the best performance. It improves data throughput for all ICA virtual channels including Thinwire display remoting, file transfer (Client Drive Mapping), printing, and multimedia redirection. The same setting is applicable for both LAN and WAN conditions.

Network stack

When set to Preferred, data transport over EDT is used as primary and fallback to TCP. With the Citirx Workspace app for Windows minimum version 1808 or Citrix Receiver for Windows minimum version 4.10 and session reliability enabled, EDT and TCP are attempted in parallel during the initial connection, session reliability reconnection, and auto client reconnect. Doing so reduces connection time if EDT is Preferred, but the required underlying UDP transport is unavailable and TCP must be used. By default, after fallback to TCP, adaptive transport continues to seek EDT every five minutes.

Important

EDT and TCP in parallel require:

  • Citrix Workspace app for Windows minimum version 1808 and session reliability.
  • Citrix Receiver for Windows minimum version 4.10 and session reliability.
  • Citrix Workspace app for Mac minimum version 1808 and session reliability.
  • Citrix Receiver for Mac minimum version 12.8 and session reliability.

By default, adaptive transport is enabled (Preferred), and EDT is used when possible, with fallback to TCP.

For testing purposes, you can set Diagnostic mode, in which case only EDT is used, and fallback to TCP is disabled.

Adaptive transport image

Interoperability with Citrix SD-WAN WAN optimization

Citrix SD-WAN WAN optimization (WANOP) offers cross-session tokenized compression (data deduplication), including URL-based video caching. WANOP provides significant bandwidth reduction. This occurs if two or more people at the office location watch the same client-fetched video, or transfer or print significant portions of the same file or document. Furthermore, by running the processes for ICA data reduction and print job compression on the branch office appliance, WANOP offers VDA server CPU offload and enables higher Citrix Virtual Apps and Desktops server scalability.

Important

When using the WANOP feature of Citrix SD-WAN, there is no need to disable Adaptive Transport. WANOP will automatically put the HDX session into TCP data transport mode, since WANOP provides equivalent flow control to EDT and adds the benefits described in the previous paragraph. Non-WANOP sessions will use EDT whenever possible. By using TCP flow control and congestion control, WANOP ensures the equivalent interactivity to EDT at high latency and moderate packet loss.

Requirements and considerations

  • Citrix Virtual Apps and Desktops: Minimum version 7 1808.
  • XenApp and XenDesktop: Minimum version 7.13.
  • VDA for Single-session OS: Minimum version 7.13.
  • VDA for Multi-session OS: Minimum version 7.13.
  • StoreFront: Minimum version 3.9.
  • Citrix Workspace app for Windows minimum version 1808
  • Citrix Receiver for Windows: Minimum version 4.7 (EDT and TCP in parallel require minimum version 4.10 and session reliability).
  • Citrix Workspace app for Mac minimum version 1808
  • Citrix Receiver for Mac: Minimum version 12.5 (EDT and TCP in parallel require minimum version 12.8 and session reliability).
  • Citrix Workspace app for iOS minimum version 1808
  • Citrix Receiver for iOS: Minimum version 7.2.
  • Citrix Workspace app for Linux minimum version 1808
  • Citrix Receiver for Linux: Minimum version 13.6 for Direct VDA Connections only and minimum version 13.7 for DTLS support using NetScaler Gateway (or DTLS for direct VDA connections).
  • Citrix Workspace app for Android minimum version 1808
  • Citrix Receiver for Android: Minimum version 3.12.3 for Direct VDA Connections only.
  • IPv4 VDAs only. IPv6 and mixed IPv6 and IPv4 configurations are not supported.
  • Citrix Gateway (Citrix ADC): Minimum versions 11.1 build 51.21, 12.0 build 35.6. We recommend minimum versions 11.1 build 55.10 or 12.0 Build 53.6 as these versions include important DTLS fragmentation fixes. For more information on configuration, see Configure Citrix Gateway to support Enlightened Data Transport and HDX Insight.

More details can be found in the original Citrix docs article: https://docs.citrix.com/en-us/citrix-virtual-apps-desktops/technical-overview/hdx/adaptive-transport.html

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