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How Citrix USB redirection supports stylus peripherals

A new feature in XenDesktop and XenApp makes it easier for stylus users, artists and engineers to link USB peripheral devices to their virtual desktops and applications, even when they're far away from the office.

Citrix USB Redirection to Cloud can improve the virtual desktop user experience and extensibility on local USB input devices.

The company's generic USB redirection allows users to connect basic peripheral devices locally and then use them within their virtual desktops. For example, a user could connect a flash drive to the local computer and then access its contents from the virtual desktop. Now, Citrix USB Redirection to Cloud provides real-time support for pressure sensitivity, enabling users to connect stylus tablets to XenDesktop and XenApp instances over wide area network (WAN) connections.

In this day and age when much of the innovation in the end-user virtualization industry focuses on enabling 3D and resource-intensive applications, Citrix USB Redirection to Cloud unlocks a pair of potentially important use cases as companies shift to more of a paperless workplace. Artists can now work within XenDesktop and XenApp without any performance issues and employees can give or collect signatures from anywhere.

Understanding USB Redirection to Cloud

Built on Citrix HDX and NVIDIA GRID remote display technologies, Citrix USB Redirection to Cloud came out in the XenDesktop and XenApp 7.6 Service Pack 3 release in October 2015.

USB Redirection to Cloud is available in two modes. Capture Mode enables workers to sign documents or collect signatures remotely, and Interactive Mode allows artists, designers and engineers to use a stylus with remote graphics-intensive applications. During a demonstration at VMworld 2015, for instance, the user drew a sketch on her tablet and saw immediate results on her virtual desktop, even though it was running inside a virtual machine (VM) 50 miles away. She experienced no lag time or performance issues, despite connecting through the conference Wi-Fi back to NVIDIA's data center hosting the XenDesktop 7.6 session.

Citrix USB Redirection to Cloud unlocks a pair of potentially important use cases as companies shift to more of a paperless workplace.

Citrix includes USB Redirection to Cloud as part of the company's HDX protocol technologies that are designed to equal the native user experience of a traditional desktop. HDX strikes a balance between server scalability and multimedia delivery by using both software- and hardware-based rendering and compression. HDX 3D Pro also plays a role. That technology includes graphics acceleration for companies with the resources to use GPUs, and its CPU-based Deep Compression codec helps servers connect the virtual desktops and applications to local peripheral devices with minimal latency.

All Citrix USB redirection features require Receiver to communicate with XenDesktop and XenApp servers and increase bandwidth efficiency. The USB Redirection to Cloud feature requires Receiver on the endpoint, but users don't need a high-end graphics processing unit (GPU) or any drivers installed on the endpoint to enable specific device types.

Citrix also provides XenDesktop and XenApp customers with optimized virtual channels -- which can include data compression -- for USB devices that don't fall under generic USB redirection, such as digital cameras, media players and point-of-sale devices. By default, only certain classes of USB devices can use this feature, but administrators can also control which devices they permit. USB Redirection to Cloud allows users to treat input devices akin to generic USB redirection, even on a WAN connection.

Where NVIDIA GRID vGPU comes in

Citrix has had little to say about NVIDIA's connection to USB Redirection to Cloud, but NVIDIA GRID technologies play a part in supporting these graphics-intensive peripherals. After all, delivering effective USB redirection of the magnitude Citrix is proposing over a WAN connection is no small feat. NVIDIA GRID GPUs come with supporting software configured to deliver virtual GPU (vGPU) hardware acceleration to multiple virtual desktops.

Despite the inclusion of supporting software, NVIDIA virtualizes the GPUs directly within the hardware, making it possible for multiple VMs to share one physical GPU, without any API abstractions. NVIDIA GRID vGPU maps, allocates and translates a VM's virtual address to the physical address of the host server. It also provides dedicated per-VM input buffers, so each VM works in its own address space, without interfering with other VMs. GRID vGPU can support up to 16 VMs for each physical GPU.

As admins grow more familiar with USB Redirection to Cloud, it could become their go-to method for enabling peripheral devices that pair with resource-intensive virtualized applications.

Next Steps

How to handle peripherals support for VDI

What's new in XenApp and XenDesktop 7.7 and 7.8?

Learn about XenDesktop's GRID vGPU feature

Dig Deeper on Virtual desktop delivery tools

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