Peripherals for XenDesktop
Often while connected to a remote session (see definitions), users need to access devices connected to their physical ends. For many of these devices, Citrix (or the device vendor) have build virtual channels that allow the use of the device in a XenApp or XenDesktop session. These virtual channels are designed to optimize the performance of the device and make it available in a transparent manner in the session. For USB devices, generic USB redirection (sending first USB data on the wire) is available as a useful fallback for specialized devices.
This post will clarify the statements above.
Definitions:
- Other - this term will be generously used to expand some of the lists below to receive new technologies or use cases that might become relevant in the future.
- Device - Auxiliary device or attached on the inside (using USB or other) physical endpoint device of the user.
- physical endpoint device User ( "device", customer or EP) - refers to PC, Mac, laptop / macbook, mobile device or other used to connect or establish a session.
- session - the resource that the user wants to use, it could be a virtual desktop, a server application, a Web application or another.
- virtual channels - Citrix HDX technologies that enable optimized use of devices in a session.
- generic redirect USB - industry term describing redirecting a physical USB port on a device to appear as a virtual USB port in the session. This redirection makes the connected USB device appear locally on the session.
- administrative settings - rarely used Settings cluttering a graphical user interface (GUI) and are available for administrators informed via GPO, register or otherwise. Note : By design, certain administrative settings could replace or disable settings on the GUI.
HDX optimized use (virtual channels)
Some virtual channels available. Note that Citrix has a virtual channel SDK (https://www.citrix.com/downloads/citrix-receiver/sdks/virtual-channel-sdk.html) that was used by device vendors to create custom virtual channels that are beyond the scope of this blog.
An important virtue is that allow the devices to be used in both the endpoint and session.
keyboard and mouse - These devices are used in both the endpoint and the session, even simultaneously, for example when accessing only applications server from an end office.
Audio (speaker / microphone) - may be needed on the endpoint, and in the session. HDX has a virtual channel and even synchronizes the volume. Some HDX multimedia optimizations play sound directly on the endpoint and take advantage of the peripheral device is available in both places
Cam -. Citrix Receiver webcam captures the images of the physical endpoint device, optimizes and sends that display session. Note: cameras can not be used simultaneously by a single application, locally or session. This is a webcam limitation, not HDX. This virtual channel requires much less bandwidth you use the USB redirection from a webcam.
USB memory sticks, CDs, DVDs, even end players -. HDX has a file access virtual channel that allows users to access all (or administratively selected) data storage devices endpoint
smart cards -. in the most secure environments (generally smartcards are used) the smart card must be available on the terminal and session and removal of the chip card is used to automatically lock or logoff
So why USB redirection?
Here are some examples of where the USB redirection may be necessary. Keep in mind when a USB device is redirected to a session, it becomes unavailable to the physical endpoint device of the user until the session is disconnected and the connection of a USB device is returned the endpoint. In addition, the more bandwidth is required to use the device (compared to the use of virtual channel) and its use affected by round trip delay.
- Devices without a virtual channel - Some devices do not just have a virtual channel. Examples include: game controllers, toys, developer access to mobile devices (eg Android ADB) inherited iTunes iPhone communications, on the other.
- specialty pointer devices - mouse space, embedded mice with additional buttons. IMPORTANT : Make sure you have more than one mouse on the physical endpoint device and does not redirect all mice to always have control of the endpoint.
- Specialty Keyboard - If a keypad includes other user interface USB redirection devices may be needed to take advantage of these. Note : Some keyboards include additional buttons that are simply multi-key shortcuts. These can be used with virtual channels without having to redirect the keyboard.
- Webcam - Strongly discouraged to use the USB redirection, but only if neccesary to access the software features advanced camera like zoom, pan, visual effects, etc. USE AT YOUR OWN RISK.
- The storage devices - When more than reading or writing files is necessary, as burning a CD / DVD, some encrypted file systems, other share.
- Non-compliant devices or use cases - Citrix made a best effort to optimize the systems, but we depend on these devices that comply with industry standards. If a device is non-compliant or it is used not according to the original USB redirection intentions might be the only way to use the device
Additional links for USB redirection :.
virtual channels - list, priorities and multi-stream
redirection eDocs
Citrix studio policies, adding the rules of the device in regedit
More information on the rules of unit (end side)
Setup for DO NOT use the parameter viewer Office
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