HP ThinPro - USB Manager

2
Introduction
USB Manager is a useful tool for managing USB devices and redirection on devices running HP ThinPro. As virtual desktop
infrastructure (VDI) becomes more powerful, more and more companies are replacing their desktop computers with thin
clients and expecting same-as-desktop behavior, including the use of USB devices. USB devices such as flash drives,
webcams, and speakers enrich the user experience; thus, many customers want this function. This paper describes how to
get the best performance from USB devices.
Background
To enable the user to use USB devices in a remote session, a protocol typically can use one of two methods: generic USB
redirection (USBR) and device mapping (also known as virtual devices).
Generic USB redirection
USBR uses a virtual USB port on the server side to simulate that a redirected USB device is plugged directly into the remote
system. To use this method, drivers must be installed on the remote system. The device displays its own name in the
Devices and Printers dialog and any applications.
This means that as long as the device works on a computer running a Windows operating system, it should work in the
remote session. Theoretically, this means the device behaves exactly as if it were being used on a local desktop.
Server VDI Session
ThinClient
Virtual USB
Device
...
011010101010100111010101
0110101010101010...
Remote OS
Install USB device
()
displayPicture()
captureAudio()
sendAudioData()
...
USB Redirection Channel
USB Protocol Layer
Data Layer
An HP Webcam is
now plugged in
! Time
to install drivers
...
In practice, this method of redirection might cause network congestion problems or issues with real-time audio or video
devices such as headsets or webcams. The USB protocol stack is not designed to handle long latency or packet loss, and
some devices perform poorly (or not at all) when redirected using USBR. For example, webcam and audio devices tend to
perform poorly in Citrix and VMware sessions with USBR. To resolve these issues, many protocols use the device mapping,
or virtual devices, method as an alternative.