Windows Server 2008 R2 Unleashed (184 page)

2008 R2.

New Redirection Features

The following are new redirection features that are introduced in Windows Server 2008 R2

Remote Desktop Services:

.
Multimedia redirection—
This feature redirects multimedia files and streams such

that audio and video content is received in its original form from the server to a

client. By doing this, multimedia content is then rendered using a client’s local

media playback capabilities.

.
Audio input and recording—
This feature enables audio recording support for

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remote clients using Voice over IP (VoIP) or speech-recognition applications.

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.
Language bar redirection—
Users can now control the language setting (for exam-

ple, right to left) for RemoteApp programs using the local language bar.

Single Sign-On

This feature allows a user with a domain account to log on once (via a password or smart

card) and access RD Session Host servers and virtual desktops without being prompted for

credentials again.

The following are some important considerations when using Single Sign-On:

. Single Sign-On is supported from Windows 7, Windows Vista, or Windows XP with

Service Pack 3 clients to a Windows Server 2008 Terminal Server or Windows Server

2008 R2 RD Session Host server. This feature is also supported between Windows

Server 2008 R2 to Windows Server 2008 servers or vice versa.

. The remote machine that a client is connecting to must be authenticated via

Kerberos or a server authentication certificate such as SSL. Or, an administrator must

enable the Allow Default Credentials with NTLM-Only Server Authentication policy.

. When saved credentials for a remote machine are already present, those credentials

take precedence over the current credentials.

Remote Desktop Connection Display

In the Remote Desktop Connection 6.0 client (and carried over to RDC 7.0), support was

added for several new features that are geared toward improving the end-user experience:

custom display resolutions, horizontal monitor spanning across multiple monitors,

Desktop Experience, Font Smoothing, and Display Data Prioritization.

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Custom Display Resolutions

In the previous Terminal Services Client, only 4:3 display resolution ratios and a maximum

resolution of 1600x1200 were supported. In the new client, additional display resolution

ratios, such as 16:9 or 16:10, and maximum resolution of 4096x2048 are now supported.

There are two ways to set a custom display resolution. The first method is to edit an .rdp

file with a text editor. In the file, add or change the following settings:

. desktopheight:i:

. desktopwidth:i:

The variable should be defined as the desired resolution. The second method is to

define the custom resolution from the command prompt:

. mstsc.exe /w: /h:

Monitor Spanning

With the monitor spanning feature, a Remote Desktop session can now be spanned across

multiple monitors. To use this feature, the monitors used must meet the following

requirements:

. The monitors must use the same resolution.

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. The monitors must be aligned horizontally.

. The total resolution across all monitors cannot exceed 4096x2048.

Monitor spanning can be enabled using two methods. The first method is to edit an .rdp

file with a text editor. In the file, add or change the following setting: Span:i:.

. = 0, monitor spanning is disabled

. = 1, monitor spanning is enabled

The second method is to enable spanning from the command prompt:

. mstsc.exe /span

Desktop Experience

The Desktop Experience feature is used to make a desktop session on an RD Session Host

server look and feel like a Windows 7 desktop. When enabled, this feature does the follow-

ing things:

. Installs a Windows 7–like desktop, which then enables features such as Windows

Media Player, desktop themes, photo management, and so on

. Allows another feature called Desktop Composition to function; Desktop

Composition is used for Windows Aero over a Remote Desktop Connection

NOTE

Desktop Composition is not supported on a multiple monitor–based Remote Desktop

session.

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Font Smoothing

An RD Session Host server can provide ClearType functionality to clients via a feature

called Font Smoothing. ClearType is a feature that is used to display fonts such that they

are clearer and smoother on displays such as an LCD monitor.

By default, ClearType is enabled in Windows Server 2008 and Windows Server 2008 R2.

To enable Font Smoothing, use the following procedure on a Remote Desktop

Connection client:

1. Open the Remote Desktop Connection client.

2. In the Remote Desktop Connection dialog box, click Options.

3. Now select the Experience tab, and select the Font Smoothing check box.

Display Data Prioritization

In past versions of Terminal Services, a user’s remote session would often become frozen

when printing or transferring files. In Windows Server 2008, a feature called Display Data

Prioritization was introduced. By design, this feature gives display, keyboard, and mouse

data a higher priority over other virtual channel traffic. The result of this design is that

virtual channel traffic, such as disk or file transfers, does not adversely affect a user’s

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ability to interact with a remote session.

By default, the bandwidth ratio with the Display Data Prioritization feature is 70:30. This

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means that 70% of the bandwidth is reserved for display and input data and 30% is

reserved for all other traffic. An administrator can adjust the bandwidth ratios by chang-

ing the following Registry values on a Terminal Server or RD Session Host server under the

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermDD subkey:

.
FlowControlDisable—
Enables and disables flow control

.
FlowControlDisplayBandwidth—
Determines relative bandwidth priority for

display (and input data)

.
FlowControlChannelBandwidth—
Determines relative bandwidth priority for

other virtual channels

.
FlowControlChargePostCompression—
Determines bandwidth allocation based

on precompression or postcompression bytes

New RDC Display Features

The following are new RDC display features that are introduced in Windows Server 2008

R2 Remote Desktop Services:

.
True multiple-monitor support—
Now up to 16 monitors of almost any size, reso-

lution, or layout are supported with RemoteApp and Remote Desktop.

Planning for Remote Desktop Services

To successfully deploy a Remote Desktop Services environment requires thorough plan-

ning and testing prior to production rollout. Criteria such as application resource usage,

security requirements, physical location, network access, licensing, fault tolerance, and

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information indicating how users will be utilizing their sessions all contribute to the way

Remote Desktop Services implementation should be designed.

Planning for Remote Desktop for Administration

Unless Remote Desktop Services is viewed as a security risk, it is recommended to enable

Remote Desktop for Administration on all internal servers to allow for remote administra-

tion. For servers that are on the Internet and for demilitarized zone (DMZ) networks,

Remote Desktop Services can be used, but access should be limited to predefined separate

IP addresses using firewall access lists to eliminate unauthorized attempts to log on to a

server. In addition, those servers should be closely monitored for unauthorized attempts to

access the system.

Planning for RD Session Host Requirements

Deploying RD Session Host servers can require a lot of planning. Because the goal is to

make applications and entire desktops available to end users, server hardware specification

and application compatibility are key components to test before a production rollout.

User Requirements

It is important to determine user requirements based on typical usage patterns, the

number of users accessing the system, and the number of applications that are required to

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run. For instance, the more applications that a user will run in a session, the more

processing power and memory will be required to optimize session performance. On

average, a Remote Desktop user who runs one application might take 10MB of RAM and

use little more than 3% of a server’s total processing time per session. A power user who

runs three or more applications simultaneously might require 40MB of RAM or much

more, depending on the applications and features being used. Use the Performance

Monitor MMC snap-in to test and validate usage statistics. The key is to not overload the

server to the point where performance is too slow to be cost effective. Additionally, the

bandwidth required by each user session will also affect how well the system performs

under various workloads.

Antivirus on Remote Desktop Services

Just as standard servers require operating system (OS)–level antivirus software, so do

Remote Desktop Services servers. When choosing an antivirus product, be sure to choose

one that is certified to run on Windows Server 2008 R2 Remote Desktop Services.

Additionally, for RD Session Host servers, install the antivirus software after adding the

role service so that scanning will work for all Remote Desktop sessions. Be sure to also

follow installation guidelines for installing applications as outlined in the “Installing

Applications” section later in this chapter.

Application Compatibility

In Remote Desktop Services, application compatibility is a term used to describe a number

of issues that might be encountered when trying to deploy an application on an RD

Session Host server. For example:

1. Some applications are written such that only a single user can use the application at

a time. With such applications, conflicts with system resources—such as files,

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Registry entries, pipes, IP addresses, and ports, which are used concurrently by multi-

ple instances of applications—might prevent an application from being concurrently

executed on an RD Session Host server.

2. In some cases, an application’s preferences might persist or manifest from one user

to the next. When this scenario occurs, there is concern with user data privacy

because settings (data) are transiting from one user to the next.

3. Additionally, an application might be written such that execution of the application

requires administrative privileges. However, in most Remote Desktop Services

deployments, regular users are not granted administrative access on an RD Session

Host server.

4. Applications might also be written such that network bandwidth or hardware

constraints cause application performance to suffer in a multiuser usage scenario. For

example, a large amount of video or animation content might overwhelm the RD

Session Host’s network connection, video card, and so on, thus reducing response

time. Or, the application was simply written such that it requires a large amount of

CPU or memory, thus monopolizing resources.

5. In some cases, an application might require devices that are not redirected by

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default, for example, devices such as CD drives, hard disk drives, and other special

devices that are not available as native devices.

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6. Or, an application is written for a particular version of Windows and, thus, its API

usage and behavior might differ on Windows Server 2008 R2.

To help administrators determine if an application is compatible before it is deployed on

an RD Session Host server, Microsoft provides a tool called the Remote Desktop Services

Application Analyzer. When this tool is executed against an application, it uses Microsoft

Application Verifier to analyze an application via intercepted function calls from that

application into the operating system and notes the calls and the parameters passed. Then

based on the information returned from the Microsoft Application Verifier, the Remote

Desktop Services Application Analyzer generates a summary report of any RDS incompati-

ble behavior and recommendations about deploying the application on an RD Session

Host server. For example:

1. Any shared resources such as files and Registry entries that the application might

require

2. Any type of access privileges issues that might be encountered

3. Any API usage requirements that might conflict with RDS

Planning for RD Session Host Sizing and Optimizing

An RD Session Host server can be sized to deliver high-performance Remote Desktop

sessions by estimating the amount of resources each user will require and the number of

users who will utilize Remote Desktop Services. Performing frequent performance testing

on the RD Session Host server helps generate accurate information on Remote Desktop