Choosing the right tablets for virtual desktop infrastructure

Planning to deliver virtual desktop tablet devices using VDI? Issues with connection brokers, bandwidth and even screen size could impact performance on these devices.

Tablet devices are hugely popular and users expect their devices to connect to corporate desktop resources. One...

way IT pros deliver desktops to tablets is with VDI -- but it's important to review whether your employees' device actually works with your remote desktop environment.

There are major differences between the different client devices on the market today and some provide a better end user experience than others. It's a good idea to try out several different devices to determine which ones work best with your VDI configuration.

Let's look at some of the features and limitations of using tablets as virtual desktop access devices and also what to watch out for.

Connection brokers
The majority of client applications available for tablets are designed to use Microsoft's Remote Desktop Protocol (RDP). While it is easy to assume that an RDP compliant app is capable of connecting to any RDP based virtual desktop, that's not always the case.

Some RDP clients establish VDI connectivity just fine, but the RDP client may or may not be compatible with the connection broker that the VDI platform uses to link client sessions to remote virtual desktops.

Furthermore, the license for some thin client applications (such as iTap RDP) only includes basic RDP connectivity. Such apps require you to license additional components if you need to pass through a Terminal Services Gateway or a connection broker.

Bandwidth considerations
Another consideration that must be taken into account is whether or not the tablet has adequate bandwidth to act as a VDI thin client. RDP works in low bandwidth environments, so bandwidth most likely won't be a problem for most tablet users. This is especially true if the user is connected using Wi-Fi or a 4G connection.

Bandwidth problems might occur, however, if your end users travel to rural areas in which high speed mobile broadband is not available.

Bandwidth consumption can also be a problem if you have users who stay connected for a long duration using a cellular connection. Most of the cellular providers limit the amount of mobile broadband bandwidth that customers can consume. Such providers typically tack huge overage charges onto customers' bills for exceeding their data transfer quota.

Screen resolution
The device's screen resolution isn't as big of a concern with tablets as it is with smartphones, which typically have smaller screens and lower resolutions, but a tablet's native screen resolution is usually different from the virtual desktop resolution. For example, the iPad 2 has a native resolution of 1024 x 768, while many virtual desktops operate at a resolution of 1280 x 1024 or 1440 x 900.

When the virtual desktop uses a different screen resolution than the tablet, it is up to the thin client app to make the virtual desktop fit onto the device's screen. There are two main ways in which this is accomplished.

Some thin client apps will compress the virtual desktop screen so that it fits onto the tablet screen. This approach leads to some loss of image quality. Depending on the difference in resolution the resulting image quality might be acceptable, or the virtual desktop screen might be borderline unreadable.

The other approach used by thin client software is to display the virtual desktop screen at its full resolution. This approach requires the user to pan the screen in order to access various parts of the desktop. The advantage of this approach is that there is no loss of display quality. The down side is that the user is not able to view the entire virtual desktop at once. Constantly panning around can be frustrating if the user runs a full screen application on the virtual desktop and it can be easy to accidentally tap (click) on something while panning the screen.

Mouse function
One last consideration is that some thin client apps offer better mouse support than others. Typically tapping the device screen emulates a mouse click. However, it is worth noting that some of the thin client apps do not provide a method for simulating a right mouse click.

Read more from Brien M. Posey

Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server and IIS. He has served as CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. As a freelance technical writer, he has written for Microsoft, TechTarget, CNET, ZDNet, MSD2D, Relevant Technologies and other technology companies.

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