The Citrix VDA – part 1

Types of VDA,  internal communication, deployment options and more on this VDA series

What is the Citrix VDA?

VDA (Virtual Delivery Agent) is the Master Piece of Citrix that allows communication between servers / desktops in a Citrix infrastructure, no matter what OS version they are using. You can have a windows server 2012 and a windows 2008 R2 on the same infrastructure also you can deploy windows 7, windows 8 and windows 10 as part of same Site depending on you users need or type of activities. The main point is to have the same VDA version installed to avoid communication and registration issues.

What VDA to use?

Initially, VDA was created only for XenDesktop, but now with the introduction of XenApp to the FMA infrastructure, Citrix created a new VDA for Hosted Share servers. That´s correct, now we have 2 different types of VDA.

They are similar but the most important difference between them is the way communication is done inside, meaning how ICA stack works on each one ( single session or multiple sessions) depending on type of OS.

  • VDA for Servers – Multi user ICA stack by extending the Windows Remote Desktop Service
  • VDA for Desktops – PicaSvc2.exe (PortICA) manages internally on VDA all communication

For both cases, VDA on desktop/server contacts VDA on Delivery controller. In other words, Broker service ( @Controller) contacts Desktop service ( @desktop/server)


VDA installation is an important step during the process. In this point, it´s defined if the machine is going to be prepared to be a Master Image or Enable Remote PC Access, Install HDX3D Pro feature and specify the list of Delivery Controllers

Fortunately we are not alone and VDA can be deployed by using different options:

  • Graphical Interface: use the GUI to configure step by step all requirements to configure VDA in not long infrastructures.
  • AD policies: You can create an AD policy to install VDA in a group of servers part of an specific OU
  • Command Line: Make it simple by creating PowerShell script to deploy VDA
  • Distribution software (System Center): As a good option, you can use any Distribution software for this task, just make sure that you will depend on it agent communication, and network, couple of factors that can impact your target dates.

Finally, on part 2 we are going to discuss what happens inside VDA infrastructure,, installation, internal communication and the Registration process

Remember! to bring a good troubleshooting you need to understand how stuff works