Using Multiple Monitors in RDP

Using Multiple Monitors in Remote Desktop Session86termserv 1 Jul 2009 11:15 PM

Introduction:

Multiple monitor support for Remote Desktop Services allows users to open a Remote Desktop connectionexpanded across all the monitors on the client computer regardless of the client monitor configuration. With thisfeature, the user can fully utilize all the monitors connected to the client computer for the Remote Desktopconnection thereby providing extra desktop space and an almost seamless experience with the client desktop thatis much improved over “Span mode”.

This feature will be part of Windows 7/Windows Server 2008 R2 release and works for connections to another clientmachine (physical or VM), or a Remote Desktop Session Host.

How to use Remote Desktop Multimon feature:To use this feature, you must:

Connect using the Remote Desktop Client 7.0 (mstsc.exe) available initially on Windows 7/Windows Server2008 R2.

1.

Enable Multimon using one of the three methods described below:a. Click “Use all monitors for the remote session” in the client (mstsc.exe) window.b. Use the “/multimon” switch on the mstsc.exe command line.c. Add “Use Multimon:i:1” to the RDP file.

2.

Connect to a computer running Windows 7 or Windows Server 2008 R2.3.

How does it look?Currently this feature displays the remote desktop on all the monitors available on the client computer. It canhandle any client monitor configuration supported by Windows.

The following images show the Remote Desktop Multimon feature in various configurations:

Display Settings UI inside a Remote Desktop session showing multiple monitors

Using Multiple Monitors in Remote Desktop Session - Remote Desktop ... http://blogs.msdn.com/b/rds/archive/2009/07/01/using-multiple-monitor...

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Remote Desktop Multimon Session with 5 monitors

PowerPoint inside Remote Desktop session showing multiple monitors

How is this different from “Span” mode?Span mode, introduced in Vista, allows the remote desktop to span across all monitors on the client as long as themonitors are arranged to form a rectangle. The remote session created when using span mode is still a single-monitor session. With multimon support, each monitor on the client machine is viewed as a distinct monitor in theremote session. Due to this fundamental difference, span mode has some restrictions that true multimon does not:

1. The primary monitor must be leftmost.

2. The set of monitors must form a rectangle (i.e. identical vertical resolution, and lined up in exact straight line).

3. The total of the resolutions must be below 4096x2048 (ex. 1600x1200+1600x1200 = 3200x1200).

For these reasons, all monitor configurations shown below are valid for Remote Desktop multimon, whereas mostof them are not valid for span mode:

With true multimon support, the client-side monitors can be arranged in any order and can be of any resolution.

Since a span mode remote session is essentially a single-monitor session, if a window in the remote desktop ismaximized, it spans across all the monitors. With true multimon support, a window will only maximize to the extentof the containing monitor.

If an application queries for the number of monitors inside a span-mode session, it will find only one monitor,


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whereas it will find as many monitors as are actually present on the client system when using true multimon RDP.This difference can change the behavior of applications such as PowerPoint.

Remote Desktop Multimon configuration properties:There are a few settings associated with the Remote Desktop Multimon feature that can be used to restrict thenumber of monitors and resolution that clients use to connect.

Restricting the maximum number of monitors:The Remote Desktop Multimon feature provides an option to restrict the number of monitors a user can use toconnect. By default, RDP protocol supports a maximum of 16 monitors. This number can be restricted to any valuebetween 1 and 16 using one of the following three approaches:

Using the “Limit maximum number of monitors per session” setting in the Remote Desktop ConfigurationTool (tsconfig.msc) as shown below:

1.

Setting the “Limit maximum number of monitors” machine group policy as shown below:

2.

By setting the MaxMonitors property in the Win32_TSClientSetting WMI class (http://msdn.microsoft.com/en-us/library/aa383778(VS.85).aspx).

3.

Restricting the maximum resolution of each monitor:By default, RDP restricts the maximum resolution to 4096 X 2048 per monitor. Additionally with multimon, thewidth and height of each remote monitor can also be restricted in one of two ways:

Setting the “Limit maximum display resolution” machine group policy as shown below:1.


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By setting the MaxXResolution and MaxYResolution properties in the Win32_TSClientSetting WMI class(http://msdn.microsoft.com/en-us/library/aa383778(VS.85).aspx).

2.

Please note that the policies and WMI settings described above apply only to connections with multiple monitorsand not when connecting with a single monitor.

Comments

CyberAxe #2 Jul 2009 1:28 AM

Thank you so much for this, this is amazing. Is this in 7RC 7100? Please include this in Live Mesh.

John #2 Jul 2009 7:48 AM

Is Aero going to be supported with MultiMonitors under the RTM of Win7?

Elton Saul #2 Jul 2009 12:02 PM

John: Aero is not supported with true RDP multimon for Win7. If you specify both desktop compositionand multimon for a Remote Desktop connection, then multimon takes precedence and you will not getdesktop composition.

-Elton [MSFT]

John #4 Jul 2009 10:22 AM

I think this will make quite a few people annoyed. Surely there are plans for Aero support across multiplemonitors?

Elton Saul #6 Jul 2009 4:40 PM

John: Making true RDP multimon and desktop composition work together is definitely something we arelooking into supporting in the future.

John Biesi #10 Jul 2009 6:52 PM

My clients are in the financial industry and plenty of them have 8x24" or 2x30" monitors, so thereresolution is well above the default 4096 x 2048 max default. Is there any way to override that so theirRemoteApp or RDP can fill the entire view?

(Note: their applications use enough resources that we usually keep a 1:1 ratio of remote sessions to TSservers)

Casey Dvorak [MSFT] #10 Jul 2009 7:41 PM

"Is this in 7RC 7100?"


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Documents

Using Multiple Monitors in RDP