How to Confirm HDX Enlightened Data Transport Protocol is Active

Adaptive transport for XenApp and XenDesktop optimizes data transport by leveraging a new Citrix protocol called Enlightened Data Transport (EDT) in preference to TCP whenever possible. Compared to TCP and UDP, EDT delivers a superior user experience on challenging long-haul WAN and Internet connections, dynamically responding to changing network conditions while maintaining high server scalability and efficient use of bandwidth. EDT is built on top of UDP and improves data throughput for all ICA virtual channels, including Thinwire display remoting, file transfer (Client Drive Mapping), printing, multimedia redirection. When UDP is not available, adaptive transport automatically reverts to TCP. EDT is a reliable protocol (guarantees delivery), and is fair to other streams on the network.



EDT runs on UDP ports 1494 and 2598.

• CGP (therefore Session Reliability) is optional on direct EDT connections between Receiver and VDA (e.g. corporate MPLS), so the VDA could be listening on UDP 1494 only

• CGP is required for EDT connections via NetScaler Gateway (VDA would be listening on UDP 2598 and 1494 but effectively using 2598).
  This is because of the role Session Reliability plays in the UDP-to-TCP fallback feature, as well as the fact that CGP is used as an authorization protocol via NetScaler (it carries the STA Ticket).

• So if you have a NetScaler Gateway, EDT requires you enable Session Reliability, which in turn enables CGP.

• Session Reliability is enabled in a Studio policy, and Storefront (Manage NetScaler Gateway > Select your NetScaler > Secure Ticket Authority > “Enable Session Reliability”)
  
  

1. In Studio, validate the policy ‘HDX Adaptive Transport’ is enabled. (Note: In XenApp and XenDesktop 7.16, EDT is enabled by default)
   1. Preferred – Transporting data over UDP is used when possible, with fallback to TCP.
   2. Diagnostic mode - This value will always transport data over UDP, and fall back to TCP is disabled. We recommend this setting only for troubleshooting.
   3. Off - TCP is always used, and EDT is disabled.

2. Verify the ICA UDP services are enabled.
   1. Open a command prompt on a VDA launched from Citrix Receiver/Receiver for Web
   2. Run the commandnetstat –a –p UDP
   3. Confirm the VDA is listening on UDP ports 1494 and 2598

3. Confirm the virtual channels are running over EDT by using the CtxSession.exe command line utility available on the VDA.
   1. Open a command prompt on a VDA launched from Citrix Receiver/Receiver for Web
   2. Run the command ctxsession.exe
   3. The output should display the session transport protocol is using UDP -> CGP -> ICA

4. In Citrix Receiver for Windows, go to Connection Center -> Select your Server -> Properties, and check for DTLS if you are connecting via NetScaler Gateway:
5. On NetScaler Gateway: Go to配置>NetScaler Gatewayand click onICA Connections. You will see details regarding the session and protocol in use (UDP if DTLS connection is established)
6. Director will also validate if EDT is active. Access the session details for the session and locate the Connection Type/Protocol. If the Connection Type is HDX and the protocol is UDP, EDT is active for the session. If the protocol is TCP, the session is in fallback or default mode.

• EDT How do I:https://support.citrix.com/pages/xaxd-how#EDT
• CTX220732 -How to Configure HDX Enlightened Data Transport Protocol
• CTX230014 -How to Troubleshoot EDT Connections
• CTX226385 -Troubleshooting DTLS and EDT on the Netscaler Gateway
• CTX230011 -EDT Session Connection/Reconnection Attempts using UDP and TCP in Parallel
• CTX230010 -Windows OS VDA 7.16 Schannel library support for DTLS
• CTX230012 -EDT Security using DTLS
• CTX231821 -How to Configure EDT when using VPN solutions
• CTX226014 -Application Launch Fails with "Unknown client error 1110" When Using EDT/DTLS on NetScaler Gateway
• CTX224373 -XenDesktop7.x Unable to launch published desktop with Adaptive transport policy enabled