# VDI Experience FAQ
Are there separate hardware requirements for Collector with the VDI extension enabled?
Since there is only one Collector, which is the same for VDI and non-VDI scenarios, the same [hardware requirements and resource usage](https://docs.nexthink.com/platform/configuring_nexthink/before-you-begin/technical-requirements/hardware-requirements) apply. The VDI Client Extension is included as a default module part of Nexthink Collector starting version 25.4.1. The extension is active by default for all devices in the environment when using VDI Experience.
Can I install the VDI Client Extension on a device that already has Collector installed?
There is no need to install Collector and the extension on the same device.
However, if you want to use the Nexthink Standalone VDI Client Extension, a lightweight agent, instead of the full range of capabilities Collector offers, you have to uninstall Collector first and then install the extension.
Can I still monitor the contractor endpoint if I have Collector from another environment?
If the contractor is not a Nexthink customer and does not have the Collector installed, then by installing the standalone VDI Client Extension, the VDI client application will provide the additional client information for the VDI sessions in your environment. The Extension only sends information when it is connecting to your own VDI environment.
If the contractor is a Nexthink customer and also has a VDI Experience licence, you will receive the relevant data when their devices connect to your VDI environment. VDI metrics are always routed to the environment the client is connecting to.
If the contractor is a Nexthink customer, but does not have a VDI Experience licence themselves, then the Extension would have to be enabled separately. To resolve such a case, contact your Nexthink representative.
If Collector is already deployed at a customer site, do I have to redeploy it for VDI completely?
The VDI Client Extension is included as a default module part of Nexthink Collector starting version 25.4.1. The extension is active by default for all devices in the environment when using VDI Experience.
Older Collector versions must be upgraded.
If I have Citrix and Omnissa and I enable VDI Experience, will Collector automatically start improved session data collection for every VDI desktop (hardware type = virtual)?
When VDI Experience is enabled, supported Collectors running on virtual desktops automatically start reporting the enhanced session metrics.
Requirements:
* A supported Collector version. For example, Horizon from 26.1, or AWS WorkSpaces from 26.2.
* The VM must have a supported VDI agent installed.
{% hint style="info" %}
Collectors automatically pick up the updated VDI entitlement and will start reporting the enhanced session data after a restart, at the latest.
In VMs with multiple VDI agents installed, such as Citrix and Horizon, the Collector reports session data for the first detected agent. This can be overridden using [MSI installer parameters or a registry configuration](https://docs.nexthink.com/platform/configuring_nexthink/bringing-data-into-your-nexthink-instance/deploying-nexthink-in-non-vdi-environment/installing-collector/installing-collector-on-windows#vm-specific-optional-parameters).
{% endhint %}
If I use Citrix DaaS to manage virtual desktops running on AVD, should I also configure the AVD connector?
No, all the information VDI Experience needs is available through the Citrix DaaS connector.
What are the firewall and connectivity requirements for the VDI Client Extension to function?
No additional firewall ports or network flows arerequired.
The VDI Client Extension communicates with the virtual desktop through the existing VDI session transport, using a Dynamic Virtual Channel (DVC). All traffic is encapsulated within the same ICA/HDX (Citrix), Blast/PCoIP (VMware), RDP (AVD/CPC), or equivalent remote display protocol session that the client already establishes with the VM.
No separate outbound or inbound connections are opened by the extension.
If the optional configuration `VDI_CLIENT_PLUGIN_PING_ADDRESS` is defined on the VM side, the configured address must also be reachable from the endpoint device running the VDI client. This uses standard network reachability, such as ICMP, and does not introduce any additional Nexthink-specific network requirements.
What new NQL data model fields does VDI Experience provide compared to the combined metrics from session.events and device_performance.events ?
VDI Experience provides the following unique metrics:
* client\_app\_version
* client\_device\_name
* client\_os\_platform
* client\_vdi\_plugin\_version
* cpu\_context\_switches
* framerate
* ica\_input\_bandwidth\_available
* ica\_input\_bandwidth\_used
* ica\_input\_session\_bandwidth
* ica\_input\_session\_linespeed
* ica\_output\_bandwidth\_available
* ica\_output\_bandwidth\_used
* ica\_output\_session\_bandwidth
* ica\_output\_session\_linespeed
* idle\_duration
* initial\_program
* last\_interaction\_time
* logon\_server
* memory\_available
* memory\_pages\_out
* memory\_usage
* network\_incoming\_errors
* network\_incoming\_packets
* network\_incoming\_throughput
* network\_outgoing\_errors
* network\_outgoing\_packets
* network\_outgoing\_throughput
* network\_wan\_latency
* network\_wired\_link\_speed
* rdp\_frame\_quality
* rdp\_frames\_skipped\_client
* rdp\_frames\_skipped\_network
* rdp\_frames\_skipped\_server
* rdp\_send\_rate
* rdp\_tcp\_bandwidth
* rdp\_tcp\_receive\_rate
* rdp\_tcp\_send\_rate
* rdp\_udp\_bandwidth
* rdp\_udp\_receive\_rate
* resolution
* session\_state
* system\_drive\_name
* system\_drive\_read\_throughput
* system\_drive\_write\_throughput
* system\_volume\_usage
* transport\_protocol
* user\_input\_delay
* vm\_agent\_version
When using Citrix, which executables or DLLs must be explicitly allowlisted in the Dynamic Virtual Channel (DVC) configuration to enable transmission of client CPU metrics?
The Citrix platform requires a configured policy to allow communication for Collector and the VDI Client Extension.
See the [citrix-virtual-channel-allowlist-configuration](https://docs.nexthink.com/platform/configuring_nexthink/bringing-data-into-your-nexthink-instance/deploying-nexthink-in-non-vdi-environment/installing-collector/windows-collector-references/citrix-virtual-channel-allowlist-configuration "mention") documentation to learn how to configure the policy.
Where does the value of CPU -> Normalized queue length come from?
It shows the total queue length divided by the number of logical CPUs. A CPU queue length higher than 2 per logical CPU indicates that processes are stalled and waiting to be executed, which might have an impact on the overall performance and perceived responsiveness.
Will the VDI Client Extension install auto updates, as standard collector agents do, or are manual updates required?
No, the standalone VDI Client Extension currently does not support automatic updates. Updates must be performed manually, for example, using software distribution, endpoint management tools, or VDI client packaging processes.
Will the VDI Client Extension installations appear on the Admin → Collector Management screen of the console?
No, the standalone VDI Client Extension does not appear in **Admin → Collector Management**, nor does it register as a managed Collector or device in inventory.
The extension does not collect or store endpoint device data. Its sole purpose is to enrich VDI session telemetry with client-side performance metrics, such as endpoint CPU and memory usage, within the virtual desktop session context.