7.0

n
“Using Log Files for Troubleshooting and to Determine USB Device IDs,” on page 219
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“Using Policies to Control USB Redirection,” on page 220
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“Troubleshooting USB Redirection Problems,” on page 230
Limitations Regarding USB Device Types
Although View does not explicitly prevent any devices from working in a remote desktop, due to factors
such as network latency and bandwidth, some devices work better than others. By default, some devices are
automatically filtered, or blocked, from being used.
In Horizon 6.0.1, together with Horizon Client 3.1 or later, you can plug USB 3.0 devices into USB 3.0 ports
on the client machine, on Windows, Linux, and Mac OS X clients. USB 3.0 devices are supported only with a
single stream. Because multiple stream support is not implemented in this release, USB device performance
is not enhanced. Some USB 3.0 devices that require a constant high throughput to function correctly might
not work in a VDI session, due to network latency.
In earlier View releases, although super-speed USB 3.0 devices are not supported, USB 3.0 devices do often
work when plugged into a USB 2.0 port on the client machine. However, there might be exceptions,
depending on the type of USB chipset on the motherboard of the client system.
The following types of devices might not be suitable for USB redirection to a remote desktop that is
deployed on a single-user machine:
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Due to the bandwidth requirements of webcams, which typically consume more than 60 Mbps of
bandwidth, webcams are not supported through USB redirection. For webcams, you can use the Real-
Time Audio-Video feature.
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The redirection of USB audio devices depends on the state of the network and is not reliable. Some
devices require a high data throughput even when they are idle. If you have the Real-Time Audio-
Video feature, audio input and output devices will work well using that feature, and you do not need to
use USB redirection for those devices.
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USB CD/DVD burning is not supported.
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Performance of some USB devices varies greatly, depending on the network latency and reliability,
especially over a WAN. For example, a single USB storage device read-request requires three round-
trips between the client and the remote desktop. A read of a complete file might require multiple USB
read operations, and the larger the latency, the longer the round-trip will take.
The file structure can be very large, depending on the format. Large USB disk drives can take several
minutes to appear in the desktop. Formatting a USB device as NTFS rather than FAT helps to decrease
the initial connection time. An unreliable network link causes retries, and performance is further
reduced.
Similarly, USB CD/DVD readers, as well as scanners and touch devices such as signature tablets, do not
work well over a latent network such as a WAN.
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The redirection of USB scanners depends on the state of the network, and scans might take longer than
normal to complete.
You can redirect the following types of devices to an RDS desktop or application:
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USB thumb flash drives
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USB hard disks
You cannot redirect other types of USB devices, and other types of USB storage devices such as security
storage drives and USB CD-ROM, to an RDS desktop or application.
Setting Up Desktop and Application Pools in View
214 VMware, Inc.