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One of the most common features virtual desktop users demand is printer redirection, but IT has to enable printing without latency problems or drivers taking up too much storage space.
Allowing workers to print from their virtual desktops isn't always easy, but it's part of providing a user experience that employees find acceptable. On the surface, printing seems simple. But remote desktop printer redirection and associated printer drivers can cause problems.
When a user prints from a physical desktop, the PC sends the job to a local printer port unless IT configures the desktop operating system (OS) to redirect the job to a network printer. But with remote desktop printing, it's the opposite. Redirecting a print job to a network printer is relatively easy, and local printing is the backup option.
Network printing vs. local printing
With network printing, several users share the same printer via a wireless network connection. Local printing, on the other hand, is when a device is physically connected to a printer.
Network printing is usually easier for VDI shops because users connect to their virtual desktops remotely. But they may still have problems with print job corruption or device timeouts when print jobs go across a wide area network, or WAN. A wireless local area network, or WLAN, tends to work better.
Networking printing can also be difficult depending on the sheer number of printers IT has to support on a single virtual desktop image. Think of all the end users sharing the same base image and how many different printers they need to access. Installing an excessive number of printer drivers into a virtual desktop OS is a common precursor to print job corruption and desktop performance and stability issues.
VDI makes it even more difficult to send print requests to a local printer directly attached to a user's device. The virtual desktop session doesn't actually run on the local machine, so the guest OS has no knowledge of what goes on with the local printer port. The local machine acts as a thin client. Without remote desktop printer redirection software, a local print job launched from a virtual desktop goes to the host server's local printer port in the data center.
The client device also plays a role in remote desktop printing. For example, local printing is easier from PCs running full OSes and thin client software, than from zero clients. A PC is printer aware and contains the necessary drivers, which means IT can configure thin client software to ignore printing requests, effectively sending the job to the PC's local port. Microsoft's Remote Desktop Connection client includes a checkbox to enable or disable printer redirection (Figure 1).
Printer driver problems
When a user initiates a print job from a virtual desktop, the VDI session host may be required to include a suitable printer driver. This is problematic, because IT might need to install dozens of different printer drivers onto each virtual desktop image to support all its printers. Installing an excessive number of printer drivers decreases the server's available memory and could even cause performance and stability problems.
Microsoft's answer is the Remote Desktop Easy Print driver. This driver replaces all the other printer-specific drivers on the Remote Desktop Session Host. When users print documents, their virtual desktops all use the Remote Desktop Easy Print driver. To enable it, IT needs to install Remote Desktop Connection and Microsoft .NET Framework 3.0 Service Pack 1 or newer. The virtual desktop will only fall back to a printer specific driver if the client does not support the Remote Desktop Easy Print driver or is missing the proper component software. If the Easy Print driver starts causing issues, then admins can use Active Directory Group Policy to disable the driver.
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