There are two versions of Rendezvous available for CSG (Citrix Gateway Service): 
- Version 1 (V1): supports bypassing the Citrix Cloud Connectors for HDX session traffic only.
- Version 2 (V2): supports bypassing the Citrix Cloud Connectors for both control traffic and HDX session traffic.

  ** Requirements are listed: https://docs.citrix.com/en-us/citrix-daas/hdx-transport/rendezvous-protocol.html **
  ** Rendezvous (v1 or v2) is not a supported functionality with On-Prem ADC **

How to check which version of Rendezvous has been using in the environment.
 

Instructions

To use Rendezvous protocol, Citrix policy [Rendezvous protocol] needs to be enabled.
https://docs.citrix.com/en-us/citrix-virtual-apps-desktops/policies/reference/ica-policy-settings.html#rendezvous-protocol
This is the common setting for Rendezvous V1 and V2.
 

To check if Rendezvous V2 is enabled or not, GctRegistration registry value is necessary to be confirmed.
On the VDA machine, check the following registry value: https://docs.citrix.com/en-us/citrix-virtual-apps-desktops/policies/reference/hdx-registry-settings.html 

Key: HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\VirtualDesktopAgent
Value type: DWORD
Value name: GctRegistration

          Value data:
          1 - To enable V2
          0 - To enable V1

         - If the value is None or empty, Rendezvous will not be used.

** This should be added automatically during the VDA installation (v2308 onwards)**

If you wish to check if the ICA Session is launched using Rendezvous or not:

- Within the Launched ICA Session run the following powershell commands:


  Posh:> Run ctxsession.exe –v

  You see a parameter called [ Rendezvous version ]
  - Rendezvous v2: Connected - V2
  - Rendezvous v1: Connected - V1
  - No Rendezvous: None or Empty


  The transport protocols in use indicate the type of connection:
   - TCP Rendezvous: TCP > SSL > CGP > ICA
   - EDT Rendezvous: UDP > DTLS > CGP > ICA
   - Proxy through Cloud Connector: TCP > CGP > ICA

  Examples:
  - TCP   [ It has failing back to TCP instead of UDP, unless you have EDT configured to Off - which it will only attempt TCP ]
  - Proxy [ Bypass Cloud Connector and communicate via Proxy]
  - SSL   [ SSL-encrypted end-to-end ]
  - CGP  [ Session Reliably is configured & present ]
  - ICA    [ Citrix ICA Session was established ]
 
 
Other Examples
============

  - TCP > SSL > CGP > ICA (TCP Rendezvous)
  - UDP > DTLS > CGP > ICA (EDT Rendezvous)
  - TCP > CGP > ICA (Not Rendezvous)
  - UDP > ICA (Session Reliability disabled)
  - UDP > CGP > ICA (Session Reliability enabled)
  - UDP > DTLS > CGP > ICA (ICA is DTLS-encrypted end-to-end)

How to validate Rendezvous version