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Five burning questions about remote desktop USB redirection

When it comes to USB device redirection, IT administrators must pay close attention to network bandwidth, latency and reliability issues.

Remote desktop USB redirection allows users to connect local peripherals such as flash drives or input devices to their virtual desktops and -- hopefully -- match native USB device performance.

The appeal for users is obvious: It makes the virtual desktop user experience much more like working on a PC. Remote desktop USB redirection may seem pretty straightforward. A company's VDI software uses a network connection to transmit the USB device's function from the physical desktop to the virtual desktop. But administrators have a lot to keep track of, including what network workers use and which devices IT should support.

Find out how to optimize the USB redirection experience and explore two tools: Citrix USB redirection and Microsoft RemoteFX.

What are the best conditions for remote desktop USB redirection to succeed?

Network bandwidth, latency and reliability issues can stop USB redirection in its tracks. IT needs to prepare for the type and strength of the networks workers will connect from. A wide area network (WAN), which is designed for geographically scattered groups, works fine for remote USB redirection, but sometimes it can't provide enough throughput to support a quality user experience.

On the other hand, local area networks, which are what on-premises employees use, work well with USB redirection. To support redirection, a network's latency rate should generally be less than 20 milliseconds, which is a difficult benchmark to reach over a WAN.

Admins must ensure their VDI software is up to date, they have the right servers in place and the desktops' operating systems (OSes) are compatible with USB redirection.

Which devices don't work well with USB redirection?

Not every peripheral device is a good fit for remote desktop USB redirection, so IT should implement USB redirection on a device-by-device basis. Scanners, for example, are notorious for causing problems, because they consume a lot of resources and run sequential processes. Some USB redirection tools block scanners, and the tools that do support them often cannot support their advanced features.

Audio and video devices are also a problem with remote desktop USB redirection because they use so much bandwidth. If an organization has to redirect a lot of those devices, including webcams, it can slow down the entire network. As a result, many redirection tools block audio and video devices.

How does Citrix USB Redirection to Cloud work?

Citrix USB Redirection to Cloud uses the company's HDX remote display technologies to support pressure-sensitive devices over WAN connections. That allows virtual desktop users to work with styluses on touchscreens in a XenDesktop or XenApp instance -- without hitting any major latency issues. This new feature became available in the XenDesktop and XenApp 7.6 Service Pack 3 in October 2015, and it's particularly useful for artists, designers and engineers who work remotely.

USB Redirection to Cloud has two modes: Capture Mode and Interactive Mode. Users can work with Capture Mode to sign documents or collect other signatures remotely. Interactive Mode enables the use of a stylus for remote graphics-intensive apps.

If an organization has to redirect a lot of audio or video devices, including webcams, it can slow down the entire network.

Stylus device redirection uses the HDX protocol's hardware- and software-based rendering and compression to try to replicate a native user experience. Citrix USB Redirection to Cloud increases bandwidth using the Citrix Receiver client software, which connects to XenDesktop and XenApp servers. All IT needs to do is install Receiver onto users' devices. The machines won't need any GPUs or drivers to work with resource-intensive devices or applications.

In addition to the Redirection to Cloud feature, Citrix optimizes the performance of USB devices such as digital cameras or media players that do not fall under the umbrella of generic USB redirection support by providing dedicated channels for those devices to connect to the network.

How well does Microsoft RemoteFX support USB redirection?

RemoteFX USB redirection can be a little bit quirky. First, organizations must run Windows Server 2008 R2 Service Pack 1 or later. In addition, each virtual desktop must include all the necessary USB device drivers. RemoteFX USB Redirection works on TCP/IP networks and is only optimized for LAN connections.

For USB devices to work, users must plug them in before they start a remote desktop session. Additionally, they cannot locally access a USB device during redirection. Users also cannot log in to virtual desktop sessions with USB biometric devices. Microsoft RemoteFX does support webcams and Voice over Internet Protocol phones, but it blocks USB display and network adapters.

What does VMware offer for USB redirection?

On VMware virtual desktops, USB redirection only works if the user's device has the most up-to-date versions of the View Agent and Horizon Client and runs Windows, Linux or Mac OS X. VMware redirection supports any USB device users want to work with, but IT can block devices that don't perform well on individual endpoints or on groups of endpoints using the Include/Exclude setting.

Administrators can customize remote USB redirection capabilities according to groups of virtual desktops through the View Agent or individual virtual desktops using the Horizon Client. Admins can enable VMware's USB device splitting feature to allow users to divide a USB device's functions between the host machine and virtual machine. For example, a user might want to forward a USB device's functionality to his virtual desktop, except for the device's mouse, allowing him to use the mouse locally and within his virtual desktop.

Next Steps

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Enterprise Desktop
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