Xendesktop to_branch_offices_v2 (1)

WHITE PAPER | Citrix XenDesktop and Branch Repeater
www.citrix.com
Performance Assessment and
Bandwidth Analysis for Delivering
XenDesktop to Branch Offices
Citrix XenDesktop and Branch Repeater
Performance Analysis

Contents
Executive Overview ..........................................................................................................................................3
Product Overview..............................................................................................................................................5
Test Environment..............................................................................................................................................7
Test Methodology..............................................................................................................................................9
Performance Results and Analysis ................................................................................................................12
Conclusion ........................................................................................................................................................23
Appendix A - Hardware and Software Configurations..............................................................................25
Appendix B - Citrix XenDesktop Configurations ......................................................................................26
Appendix C – Citrix Branch Repeater Configurations ..............................................................................27
Appendix D – Login VSI Pro Configurations ............................................................................................27
Appendix E – HDX MediaStream Active Directory GPOs.....................................................................28
Appendix F - References ................................................................................................................................28

Executive Overview
Desktop virtualization is rapidly gaining momentum in the IT industry. The desire to centralize and
secure desktops, applications, and corporate data is a driving factor behind this trend. To make the
transition to a virtual desktop platform CIOs and administrators alike must ensure that all users have
a positive experience with the virtual desktop, even if they work in remote branch offices away from
the corporate datacenter. This whitepaper details the network bandwidth requirements per user for
a variety of use cases and provides the IT professional with critical data to plan the delivery of Citrix
virtual desktops across a WAN.
To provide users with a positive virtual desktop experience, IT professionals must ensure an
acceptable level of desktop performance can be provided to both corporate users as well as the
branch office users. The purpose of this paper is to provide the network administrator with
guidance for determining the amount of available bandwidth required for a Citrix XenDesktop
solution based on popular use cases. This paper details how the introduction of Citrix Branch
Repeater can provide significant bandwidth savings and performance improvements for branch
office users and can in some cases negate the need for a costly network upgrade.
This unique partnership of combining Citrix XenDesktop with Branch Repeater is the only solution
on the market where the ability to compress native XenDesktop traffic is transitioned to a WAN
optimization solution, Citrix Branch Repeater, for optimal virtual desktop performance. The
adaptive orchestration where XenDesktop becomes Branch Repeater-aware provides significant
savings in the overall bandwidth requirements for XenDesktop as shown throughout this report.
The Citrix Consulting Solutions team conducted all the testing represented in this paper within the
Consulting lab environment at Citrix headquarters. All tests were based on the widely accepted
LoginVSI methodology and focused on common workflows such as standard MS Office tasks,
internet browsing, printing, and video.
Table 1 represents a high level overview of the bandwidth requirements for standard virtual desktop
workflows as represented in this document. The Branch Repeater numbers displayed in the table
represent a warm run (the test data passed through the Branch Repeater prior to testing). When data
first passes through Branch Repeater, compression algorithms are utilized to optimize TCP traffic
and cache the data stream. During the second request for the same data, Branch Repeater utilizes a
tokenizing engine to serve recognized data streams from local cache rather than pulling the same
data stream across the WAN. Therefore, the greatest bandwidth savings is recognized in all data
transfers after the first pass as shown in the following table.

Workflow Avg User
Load
Environment Avg Bandwidth
Consumed
Office 20
Native XenDesktop 43 kbps
XenDesktop & Branch Repeater 31 kbps
Internet Browsing 10-12
Printing 1
(5MB MS Word & PDF)
1
Native XenDesktop 553-593 kbps
XenDesktop & Branch Repeater 155-180 kbps
Flash Video
(server-rendered)
5
Standard WMV Video
(client-rendered)
4
High Definition WMV Video 2
(client-rendered)
1-2
Table 1: Average Bandwidth per Session
The Citrix Branch Repeater plays a critical role in optimizing an existing WAN connection and
improving the overall virtual desktop user experience in the branch office. The following key
findings from this report emphasize the strategic cost savings and performance improvement a
Branch Repeater solution can provide for any branch office XenDesktop deployment.
 Citrix Branch Repeater can reduce the overall average bandwidth consumed per session by
up to 89%.
 Citrix Branch Repeater can reduce the amount of time it takes for a XenDesktop session to
launch on a congested WAN connection by up to 40%.
 Citrix Branch Repeater can double the number of users able to execute similar virtual
desktop activities on the same congested WAN connection.
 Citrix Branch Repeater can reduce the amount of time it takes for the print request to spool
from the virtual desktop to the branch office print server by up to 60%.
1
To assess the maximum amount of bandwidth consumed for a single print job only one document was printed
per test on an uncongested WAN to provide the most conservative guidance. Additional XenDesktop policies and
Branch Repeater priority queuing can be implemented to optimize bandwidth availability during print jobs.
2
The WAN parameters for the HD video were increased to 10mbps given that the data rate of the High Definition
video was 6.5 mbps. Only 1 user was evaluated on the 10mbps for native XenDesktop, but 2 users were evaluated
for XenDesktop with Branch Repeater.

Product Overview
Citrix XenDesktop
Citrix XenDesktop is a desktop virtualization solution that delivers Windows desktops as an on-
demand service to any user, anywhere. With FlexCast™ delivery technology, XenDesktop can
quickly and securely deliver individual applications or complete desktops to the entire enterprise,
whether they are task workers, knowledge workers or mobile workers. Users now have the flexibility
to access their desktop on any device, anytime, with a high-definition user experience. With
XenDesktop, IT can manage single instances of each OS, application and user profile and
dynamically assemble them to increase business agility and greatly simplify desktop management.
XenDesktop’s open architecture enables customers to easily adopt desktop virtualization using any
hypervisor, storage or management infrastructure.
Citrix Branch Repeater
Citrix Branch Repeater is a branch optimization solution that accelerates and simplifies branch
infrastructure. Branch Repeater solutions reduce IT costs and increase user productivity by
simplifying branch startup and management, and providing users the best access experience.
The Branch Repeater products achieve WAN optimization by combining a variety of technologies:
 TCP Optimization: Branch Repeater is a symmetric solution, where a Branch Repeater is
located at each end of the WAN connection (in the datacenter and in the branch office)
recognize each other’s presence and employ RFC compliant TCP optimization techniques
that ensure optimal utilization of the network bandwidth.
 Traffic Prioritization (QoS): Administrators can classify network bandwidth based on TCP
port numbers and IP ranges to prioritize the delivery of TCP segments based on the
classification. Furthermore, Branch Repeater recognizes the priorities of the various ICA
virtual channels and can ensure preferential treatment of real-time critical data such as audio.
 Compression: Branch Repeater can detect repeating patterns in the transmitted data and
utilize very small tokens across the WAN to identify such repeating data patterns and serve
the data to the user out of the appliance memory; therefore, restricting the amount of data
required to traverse the WAN and improving user experience.
 Protocol Optimization: Branch Repeater can optimize a variety of common application
protocols. Citrix XenDesktop leverages the ICA protocol, which employs a variety of
optimization and security features natively. In order to apply compression, a WAN optimizer
must be able to decrypt the ICA workload, identify repeating patterns within the ICA virtual
channels, apply the optimization, and re-encrypt the data stream. This is why Citrix Branch
Repeater is the only WAN optimization product capable of directly optimizing the ICA
payloads on the protocol level.

This paper focuses on the virtual desktop acceleration gained from the joint deployment of Citrix
Repeater in the datacenter and Citrix Branch Repeater in the remote branch office.
Citrix High Definition User Experience
With the release of Citrix XenDesktop 4, Citrix committed to providing the best high definition user
experience through the introduction of HDX technology. Citrix HDX technology builds on
existing Citrix user experience innovations from the datacenter to the device, adding enhancements
for multimedia, voice, video and 3D graphics. Citrix HDX is comprised the following categories:
 HDX Broadcast – Ensures high-performance of virtual desktops and applications over any
network, including high-latency and low-bandwidth environments.
 HDX WAN Optimization – Optimizes performance by utilizing Citix Branch Repeater to
cache bandwidth intensive data and graphics and deliver them from the most efficient
location.
 HDX MediaStream – Accelerates multimedia performance through compression or, when
possible, redirection and client-side rendering.
 HDX RealTime – Enhances real-time voice and video using advanced encoding and
streaming to ensure a no compromise end-user experience.
 HDX 3D – Optimizes the performance of everything from graphics-intensive 2D
environments to advanced 3D geospatial applications using software and hardware based
rendering in the datacenter and on the device.
 HDX Plug-n-Play – Enables simple connectivity for all local devices in a virtualized
environment, including USB, multi-monitor, printers and peripherals.
Citrix XenServer
Citrix XenServer is open, powerful server virtualization that radically reduces datacenter costs by
transforming static and complex datacenter environments into more dynamic, easy-to-manage server
workload delivery centers. Based on the open source Xen® hypervisor, XenServer delivers a secure
and mature server virtualization platform with near bare-metal performance.
Login VSI 2.1 Pro (Benchmarking Tool)
Login VSI 2.1 is a benchmarking tool specifically designed for SBC and VDI environments. VSI
loads the system with simulated user workload, and focuses on how much user load can be
generated within the system before performance degrades. VSI is a completely platform and
protocol independent tool. The VSI implementation and configuration is very simple and provides
engineers and administrators with a turn-key benchmark solution that allows testers to gather
metrics in days versus weeks. The tool is available in two versions. The free version is configured
with a standard user workflow that executes a combination of Microsoft Office, Internet Explorer

and printing tasks. The VSI Pro (paid version) provides testers the ability to generate workloads that
vary in intensity as well as the ability to execute custom workflows.
Login Consultants was the first company worldwide to be appointed as a Citrix Managed
Consultancy Provider. The strategic relationship between Citrix and Login Consultants has
developed XenDesktop testing standards that are proven and repeatable in any customer
environment.
Test Environment
The Citrix Consulting Solutions team is committed to architecting and implementing real-world test
environments based on prior Citrix Consulting customer engagements. The following test
environment was constructed within the Consulting Solutions lab in Fort Lauderdale, Florida to
emulate a branch office scenario where end users are connecting to their virtual desktop over a
dedicated WAN link. The test environment consisted of a datacenter environment with Citrix
Repeater and a remote branch office environment with Citrix Branch Repeater connected by a
simulated WAN. All XenDesktop, infrastructure, and branch office machines were virtualized using
Citrix XenServer.
Branch Office Datacenter
T E CHN OL O G IES
MGMT LAN A LAN BCONSOLE
LINKTROPY
MINI
POWER STATUS
Print Server
Login VSI
File Share
Citrix XenServer
Login VSI Pro
Launcher
Login VSI Pro
Launcher
Login VSI Pro
Launcher
Virtual Desktops
Desktop Pool
Citrix XenServer
Desktop Pool
Citrix XenServer
Desktop Pool
Citrix XenServer
XenDesktop Environment
Delivery Controller
with Web Interface
Citrix Provisioning
Server
Citrix XenServer
Citrix Branch Repeater
Citrix Repeater
T1, 80ms Latency,
1% Packet Loss
Switch
Infrastructure
SQL Server
Active Directory
Citrix License
Server
Citrix
XenServer
Figure 1: Performance Assessment and Bandwidth Analysis Environment Architecture
The Citrix Consulting Solutions team leveraged Login VSI 2.0 Pro to create a standard method for
launching simultaneous virtual desktops through XenDesktop and a standard process for executing

automated end user workflows that incorporated applications such as Microsoft Office 2007 and
Internet Explorer 7 web browsing. Although the number of users and workflows varied, the
following steps provide a high level overview of the test execution process utilizing Login VSI 2.0
Pro:
 Login VSI 2.0 Pro supports multiple simultaneous launchers through a master and slave
configuration. To execute a test, the Login VSI 2.0 Pro console on the master launcher is
configured with desktop connection information and a UNC path to the Login VSI share.
The Login VSI share must be on a file server that is accessible to both the launcher and the
virtual desktop executing the end user workflow.
 The Login VSI share contains four critical files: VSILauncher.ini, VSITarget.ini,
LoginVSI.csv and LoginVSI.lic. The VSILauncher.ini file provides criteria regarding
connection information for accessing the Delivery Controller and launcher information such
as the list of additional launchers acting as slaves. The VSITarget.ini file is configurable in
the Pro version only to support light, medium, heavy or custom workflows. The
LoginVSI.csv file contains a list of unique usernames and passwords. The LoginVSI.lic
license file is necessary for the Pro version of the tool.
 To execute a test, the ‘custom connection’ method is leveraged and a custom Python script
which emulates Internet Explorer browser sessions is used to launch multiple Web Interface
sessions.
 The Python script is also leveraged to automatically enter multiple test user credentials on
each Web Interface session launched. These credentials are stored in the specified
LoginVSI.csv file.
 Each Launcher had the Citrix Online Plug-in installed locally prior to test execution.
 After the user was authenticated, the virtual desktop was automatically launched. The Login
VSI Launcher completed the process of launching desktop connections at this point.
 The standard vDisk used for each virtual desktop was preconfigured with Microsoft Office
2007, RealTime Player, Windows Media Player and the Login VSI target deployment
software. Users were granted administrative privileges (as part of the Login VSI installation)
and all the workflow scripts were tested to ensure that all pop-up warnings were removed.
 The Login VSI component on the virtual desktop referenced the VSITarget.ini file on the
VSI share. The VSITarget.ini file provided the component with instructions regarding the
user workflow.
 The user workflow was embedded within the local desktop. All the keystrokes and mouse
clicks that are executed during the workflow are scripted within the virtual desktop;
therefore, there are no keystrokes or mouse clicks from the launcher in the branch office
traversing the WAN to communicate with the XenDesktop virtual desktop.

Test Methodology
The project had two objectives. The first objective was to determine the average amount of
bandwidth required for a XenDesktop virtual desktop accessed from a branch office. The second
objective was to measure the performance improvement that a Citrix Branch Repeater solution can
provide to the branch office environment when using XenDesktop. The testing methodology was
designed to assess both of these key objectives under varying user workflows and to provide
guidance to the customer community regarding bandwidth requirements for a branch office Citrix
XenDesktop deployment without a Citrix Branch Repeater solution and the performance
improvements gained from incorporating a Citrix Branch Repeater in a XenDesktop solution.
Given that user activities can vary throughout the work day, the test methodology separated end
user tasks into four main categories: Microsoft Office, Internet Explorer, Printing, and Video
activities.
In an effort to minimize the variables associated with the testing, a single WAN connection was
selected between the branch office and the datacenter hosting the virtual desktops. It was
determined that an intra-continental T1 connection would resemble a large portion of the user
community looking to implement XenDesktop in a branch office and the bandwidth numbers
provided in this document can be used as guidance for determining the correct WAN connection
type for any remote office. The WAN parameters select were based on a more restrictive WAN
connection to provide conservative guidance. For the purpose of the testing reflected in this
document, the following WAN parameters were configured utilizing an Apposite Linktropy WAN
emulator:
Data
Throughput
Latency Packet Loss
1.5 Mbps 80ms 1%
Table 2: Test Environment WAN Connection
Microsoft Office 2007 Workflow
The Login VSI tool provides a standard medium user load workflow that incorporates Office,
Solidata PDF writer with Adobe Reader, and Internet Explorer. For the purpose of this Office
specific workflow, the default Login VSI workflow was edited to only execute the Office portion of
the overall standard medium workflow. Login VSI workflows for Office are configured to
randomize the content for each user. The Office content accessed and modified during the
workflow execution is derived from a randomized pool of files to ensure that the users are executing
different activities. The Login VSI Office workflow is strategic to the Branch Repeater aspect of
this testing because unlike the other workflows, the Office content executed with the Login VSI
workflow is uniquely different for each user. By having each user access different emails and
PowerPoint presentations, the data gathered from the Office workflow most closely resembles a
real-world customer environment.

To execute the Office workflow, the user load was incremented in user counts of five for each test
cycle. The launcher was configured with a 30-second interval between each user launch. During
each test cycle, a single virtual desktop was monitored by the Consulting team to determine the
overall performance and responsiveness of the environment. This subjective assessment was made
by evaluating the responsiveness to typing, mouse clicks, and screen refreshes during each test cycle.
Several metrics were measured in addition to the overall user experience. The average bandwidth
consumed for the workflow was evaluated with and without Branch Repeater. In order to have all
the necessary users online at the same time to gather these metrics, the workflow would loop
continuously to allow the WAN emulator to record all active sessions during the same 10-minute
time interval given that there was a 30-second window between user launches. For example, to
assess 10 users in the environment the overall workflow would execute for 15 minutes to allow all
10 users to be active for 10 minutes to get a true average of bandwidth consumed. Additional
metrics such as XenDesktop launch time and Branch Repeater compression ratios were also
gathered for this workflow. It should be noted that the Branch Repeater numbers represented in
this testing reflect a warm run. A warm run is when the Branch Repeater has executed the Office
workflow prior to the test cycle starting. With a warm run not all documents are seen prior to the
start of the workflow since the content varies from user to user.
Internet Explorer Workflow
The Consulting team developed a customized Internet Explorer workflow that accesses the
following websites: Citrix.com, Yahoo Finance, MSN, Gap.com, Amazon.com, Google Maps and
CNN. The customized workflow is over 11 minutes in duration. The Login VSI launcher was used
in conjunction with the customized workflow to bring users online in the same 30-second launch
interval used by the Office workflow scenario. Given that the workflow was only 11 minutes in
duration, the workflow continued to loop for each user to allow all users to be active for a 10-
minute window for measurements purposes. It should be mentioned that the websites specified in
the Internet Explorer workflow did include stock tickers and rotating ads, but the overall content
was similar in nature for every user added to the environment.
The execution of this workflow was comparable in design to the Office workflow, so only the
metrics specific to the Internet Explorer component of these workflows were collected. The overall
user experience was monitored in the same fashion as the Office workflow. A single virtual desktop
was monitored by the Consulting team to determine the overall performance and responsiveness of
the environment. This subjective assessment was made by evaluating the responsiveness to typing,
mouse clicks, and screen refreshes during each test cycle. The additional metrics gathered specific to
the Internet Explorer workflow included average bandwidth consumed and Branch Repeater
compression ratios. It should be noted that the Branch Repeater numbers represented in the
Internet Explorer workflow reflect a warm run.

Printing Workflow
Unlike the previous two workflows where the user continuously interacts with the desktop, a print
job is a single request from the virtual desktop to the printer. To assess the printing performance
for a variety of applications, a single user printed a 5MB Microsoft Word document and a 5MB PDF
file from within the virtual XenDesktop environment. The print server was located in the branch
office which required the virtual desktop to spool the print request across the WAN. Citrix
XenDesktop does support the same printer policies that Citrix XenApp provides. By default, Citrix
XenDesktop polices are configured to set print spool requests as a low priority. For more
information regarding the XenDesktop policies used in this testing, please reference the Appendix A
of this document
For the Printing workflows, key metrics such as print spooling execution time, total bandwidth
consumed, and Branch Repeater compression ratios were gathered. It should be noted that the
Branch Repeater numbers represented in the printing workflow reflect a warm run.
Video Workflow
One of the strategic differences with XenDesktop versus competitive products is the HDX
technologies. When possible, HDX MediaStream leverages the processing power of the endpoint
device to render multimedia content. The video workflow assessed the performance of Windows
video utilizing the HDX MediaStream for Windows technology and Flash video utilizing standard
server-side video rendering.
HDX MediaStream for Windows
HDX MediaStream with Windows is a very powerful technology for a branch office virtual desktop
deployment. HDX MediaStream leverages the processing power of the branch office end-user
device to render the multimedia content. This allows the video stream to be sent to the branch
office in its native format, which typically requires much less bandwidth than rendering the video
within the virtual desktop, and sending all the individual frames across the WAN. For the purpose
of the testing in this paper, the process of obtaining the Windows Media content and rendering the
Windows Media content was divided between the virtual desktop running in the datacenter and the
end user device running in the branch office. The virtual desktop was responsible for fetching the
content from a file server in the datacenter that could only be accessed by the virtual desktop. The
virtual desktop fetched the WMV file from the file server and sent the content to the branch office
device in its native format. Once the branch office device received the content, the device utilized
its local Windows Media Player to render the video content; therefore, the video appears in the
virtual desktop with the same quality as rendering the video on the local device. Windows Media
Player was used to render the videos in this testing, but other media players based on DirectShow,
DMO or Media Foundation could also be used
In this test scenario, the server-side fetching and client-side rendering of two Windows Media
Videos were monitored. The first WMV file was a 5MB video, six minutes in duration with a data
rate of 70kbps, frame rate of 15 frames/second, and a 320x252 display. This 5MB video was

considered to be a standard video. The second video was labeled as a high definition (HD) video.
The HD video was the robotica.wmv file downloadable from the Microsoft WMV HD Conent
Showcase website. The HD video was a 16MB video, twenty-one seconds in duration with a data
rate of 6500kbps, frame rate of 23 frames/second, and a 1280x720 display.
For each video test scenario the video duration was a key component in evaluating the overall
bandwidth for one to four users. In this scenario the video was executed concurrently across all
sessions without a 30-second launch interval as documented for the other workflows. The overall
user experience was evaluated based on the screen refreshes and overall video appearance. Other
key metrics included the total bandwidth consumed and the time duration for the data transfer. It
should be noted that the Branch Repeater numbers represented in the HDX MediaStream workflow
reflect a warm run.
Flash Video
When Flash video is viewed across the WAN, XenDesktop utilizes server-side fetching and server-
side rendering for the Flash video. With server-side fetching and server-side rendering, the Flash
video is rendered within the virtual desktop in the datacenter and the screen updates are sent across
the WAN connection.
For each test scenario, the Flash video was a 39MB flash video that was forty-one minutes, with a
data rate of 66.5kbps, frame rate of 9.9 frames/second, and a 320x240 display. The Shockwave
Flash video player was installed on the virtual desktop. The test scenarios included both a single–
user and a five-user test. The five-user test leveraged the VSI launcher where users had a 30-second
interval between session launches. The video ran for fifteen minutes to gather metrics for a ten-
minute average after all five users were actively watching the video. For this testing the overall user
experience was evaluated based on the screen refreshes and overall video appearance. Other key
metrics included the average bandwidth consumed. It should also be mentioned that the Branch
Repeater numbers represented in this testing reflect a warm run.
Performance Results and Analysis
Microsoft Office 2007 Workflows
Microsoft Office is the most frequently virtualized application utilizing Citrix technology. Figure 2
shows the average bandwidth consumed per user across the WAN as users performing Office
workflow were added to the environment and Figure 3 shows total average bandwidth consumed
for all users across the WAN.

Figure 2: Office Workflow-Average Bandwidth Consumed per User
Average Bandwidth consumed per User
XenDesktop uses the ICA protocol to render the virtual desktop on the end user device. The ICA
protocol is a highly optimized protocol by design. The ICA protocol will consume as much
available bandwidth as possible on a given link as noted by the higher bandwidth consumed during
low user load. When the amount of available bandwidth is restricted, the ICA protocol performs
well until the bandwidth restriction becomes too severe and user performance is degraded. This
aspect of the protocol made it important to also monitor user performance of the virtual desktop
executing the Office workflow.
In the Average Bandwidth Consumed per User graph, the average bandwidth consumed line flattens
as the number of users continues to increase. The objective of this testing was not to determine the
minimum amount of bandwidth required, instead the objective was to identify the average amount
of bandwidth required to provide a user experience parallel to that of the local desktop. Figure 2
shows that the average bandwidth consumed per user required for the Office workflow for native
XenDesktop is effectively 43 kbps.
As part of the improvements in XenDesktop 4 and Branch Repeater 5, Branch Repeater can now
accelerate the delivery of desktops by letting XenDesktop detect when Branch Repeaters are active
in the environment. Branch Repeater will recognize and parse the incoming ICA stream and take
part in the initial connection negotiations. Once the Citrix Online Plug-in and Delivery Controller
are aware of the Branch Repeaters, they will disable their native ICA compressors and hand-off the
compression to the Branch Repeaters.
0.00
10.00
20.00
30.00
40.00
50.00
60.00
0 5 10 15 20 25
AvgBandwidthConsumed
perUser(kbps)
Users
Office Workflow
XenDesktop Average Bandwidth per User (Native)
XenDesktop Average Bandwidth per User (with Branch Repeater)

When the Branch Repeater was introduced into the environment, the average bandwidth per user
required for the Office workflow was reduced by 28% to 31 kbps while maintaining an excellent
overall user experience.
Figure 3: Office Workflow-Bandwidth Consumed for All Users
Bandwidth Consumed for All Users
One of the key benefits of introducing a Branch Repeater into any branch office scenario is the
ability to add more users to the existing environment without upgrading the WAN connection.
When reviewing the total bandwidth consumed for all users, it can be derived that total bandwidth
consumed for 20 users was approximately 861 kbps for native XenDesktop and 622 kbps with
Branch Repeater. Given that a Branch Repeater user consumes an average of 31 kbps, then 7.7
additional users could be added to the environment to reach the same level of WAN utilization
shown without a Branch Repeater; therefore, approximately 40% more users can be added to a
XenDesktop Office workflow environment with a Branch Repeater solution in place.
0
100
200
300
400
500
600
700
800
900
1000
0 5 10 15 20 25
AvgBandwidthConsumed(kbps)
Users
Office Workflow
XenDesktop Average Bandwidth (Native)
XenDesktop Average Bandwidth (with Branch Repeater)

Figure 4: Office Workflow-XenDesktop Launch Time
XenDesktop Launch Time
There is an inherent amount of time between the user entering their credentials into Web Interface
and the appearance of the virtual desktop display on the user’s screen. During this period, the
following actions take place:
 Web Interface passes the validated credentials to the Delivery Controller XML Service
 The XML Service authenticates the user against Active Directory
 The XML Service then determines which virtual desktops are available to that user
 The available desktop information is sent to Web Interface
 Web Interface presents the desktop information to the user device
 Web Interface creates an ICA file for user device
 The Citrix Online Plug-in on the user device establishes the ICA connection over the WAN
to the desktop
In this test environment, the average XenDesktop launch time took approximately 6 seconds
(Figure 4 displays the logon times as collected during the testing cycle). When WAN traffic
consumed more than 60% of the overall available bandwidth, the launch time increased to
approximately 10 seconds. When a Citrix Branch Repeater is introduced into the congested
environment, the launch time of the XenDesktop session returned to the original 6 seconds,
providing up to 40% XenDesktop Session Launch time improvements.
0 5 10 15
XenDesktop Launch Time with Branch
Repeater Low WAN Congestion
Native XenDesktop Launch Time Low WAN
Congestion
XenDesktop Launch Time with Branch
Repeater High WAN Congestion
Native XenDesktop Launch Time High WAN
Congestion
Seconds
XenDesktop Launch Time

Internet Explorer Workflows
Internet Explorer browsing through a virtual desktop can be more bandwidth intensive than Office.
Figures 5 and 6 show the average bandwidth consumed per user across the WAN as users are added
to the environment and the total bandwidth consumed across the WAN for all users executing the
Internet Explorer workflow respectively.
Figure 5: Internet Explorer Workflow-Average Bandwidth Consumed per User
Average Bandwidth Consumed per User
In the Average Bandwidth Consumed per User graph, the average bandwidth consumed line flattens
as the number of users continues to increase. The Internet Explorer workflow was more bandwidth
intensive than the Office workflow and the end user experience began to degrade around 12 users.
Therefore, the average bandwidth per user required for the Internet Explorer workflow for native
XenDesktop was extracted from the 10-12 user range and is approximately 85 kbps per user. When
the Branch Repeater was introduced into the environment, the average bandwidth per user required
for the Internet Explorer workflow was reduced by 55% to a more WAN-friendly 38 kbps per user
while maintaining an excellent user experience overall.
0.00
20.00
40.00
60.00
80.00
100.00
120.00
0 2 4 6 8 10 12 14 16
AvgBandwidthConsumed
perUser(kbps)
Users
XenDesktop Average Bandwidth per User (Native)
XenDesktop Average Bandwidth per User (with Branch Repeater)

Figure 6: Internet Explorer Workflow-Bandwidth Consumed for All Users
Bandwidth Consumed for All Users
When reviewing the Bandwidth Consumed for All Users graph, the data indicates that total average
bandwidth in the 10-12 user range is approximately 900 kbps for native XenDesktop and 425 kbps
with Branch Repeater. Given that a Branch Repeater user consumes only 38 kbps, then 12.5
additional users could be added to the environment to reach the same level of WAN utilization
shown without a Branch Repeater. In other words, the user count supported across a WAN link can
be doubled for Internet Explorer based workflows when a Branch Repeater solution is in place.
Printing Workflows
Figures 7 and 8 show the performance data for printing both a Microsoft Word and PDF document
installed on the local desktop to a printer in the remote branch office for a single user.
0
200
400
600
800
1000
1200
1400
0 2 4 6 8 10 12 14 16
AvgDataBandwidth(kbps)
Users
XenDesktop Average Bandwidth (Native)
XenDesktop Average Bandwidth (with Branch Repeater)

Figure 7: Printing Workflow-Total Bandwidth per Print Job
Total Bandwidth
The protocol acceleration benefits of Branch Repeater are very pronounced in a data transfer
situation such as the print workflow. The Total Bandwidth per Print Job graph shows that with a
Branch Repeater solution the data transfer is reduced by 84% for the 5MB Word document and by
89% for the 5MB PDF document.
Figure 8: Printing Workflow-Average Bandwidth Consumed per Document
0 500 1000 1500 2000 2500
5MB PDF Native XenDesktop
5MB Word Native XenDesktop
5MB Word XenDesktop with Branch
Repeater
5MB PDF XenDesktop with Branch
Repeater
Total Bandwidth (KB)
Printing Workflow
0 100 200 300 400 500 600 700
5MB Word Native XenDesktop
5MB PDF Native XenDesktop
5MB Word XenDesktop with Branch
Repeater
5MB PDF XenDesktop with Branch
Repeater
Avg Bandwidth (kbps)
Printing Workflow

Average Bandwidth Consumed per Document
Determining the average bandwidth consumed per user is difficult given the variation in content and
file size for a larger number of users. Instead, the Consulting team recommends determining
guidance for the average bandwidth consumed per document. Once the guidance for document
bandwidth requirements is determined, the end user print behaviors must be identified. The
following numbers represent a single user executing a print job on a T1 with all bandwidth available
for the single print request (maximum bandwidth consumed). Please note that the results will be
different on a congested WAN.
Document
Average Bandwidth
(kbps)
Time to Spool
Print Job
(seconds)
Native
XenDesktop
5MB Word 593 kbps 28s
5MB PDF 533 kbps 31s
XenDesktop with
Branch Repeater
5MB Word 180 kbps 15s
5MB PDF 155 kbps 12s
Table 3: Printing Workflow
If the branch office user community does a significant amount of printing, then the Consulting team
recommends utilizing the XenDesktop policies to configure session limits on the amount of
bandwidth a print job can consume. There will be a time trade-off for implementing the
XenDesktop policy, but the end user experience in the virtual desktop will not be as impacted when
a large print job is spooling over the WAN. When a Branch Repeater is configured in the
environment, then the Consulting team recommends configuring the Branch Repeater to prioritize
print traffic relative to other (ICA and non-ICA) traffic, rather than just limiting the bandwidth to a
set amount for printing. With Branch Repeater traffic prioritization (QoS), the Branch Repeater can
prioritize the accelerated traffic to ensure that all available bandwidth is consumed.
Video Workflows
The video workflows were separated into three distinct: HDX MediaStream for Standard Windows
Media Video, HDX MediaStream for High Definition Windows Media Video, and Flash Video
(Server-side Rendering).

Figure 9: Video Workflow-Average Bandwidth Consumed per User
Flash Video (Server-side Rendering)
The WAN connection selected for the test data shown throughout this document was configured
for 80ms latency roundtrip. (HDX MediaStream for Flash can render Flash content on the user
device, thereby increasing server scalability, only if the connection latency is below 30ms roundtrip.)
For all the testing in this document, the latency was configured to 80ms roundtrip, this then forced
XenDesktop to render the Flash video server-side. (QuickTime and Silverlight videos are similarly
rendered server-side.)
As Figure 9 shows, the benefits of introducing a Branch Repeater into a server-side rendered video
provides an average bandwidth consumed savings of approximately 25%. The average bandwidth
consumed for native XenDesktop rendering server-side was 174 kbps while the average bandwidth
consumed with Branch Repeater was 128 kbps.
0 50 100 150 200
MediaStream for Flash Native
XenDesktop
MediaStream for Flash for XenDesktop
with Branch Repeater
Avg Bandwidth per User (kbps)
Video Workflow - Flash

Figure 10: Video Workflow-Average Bandwidth Consumed per Video
HDX MediaStream for Standard WMV
The Standard WMV file was fetched on the server-side and rendered on the client utilizing the HDX
MediaStream technology. This configuration allows the video to be sent to the end-user device in its
compact native format versus sending frame updates as represented in the Flash video results.
When the WMV file is sent to the client for rendering, the data transfer time of that WMV file does
not continue for the entire duration of the video. For example, in this test the total data transfer
time of the standard WMV file for native XenDesktop was approximately 400 seconds. When the
video was played, there was an original spike in data transfer at the start of the video varying
between 30 to 100 seconds based on the number of videos actively playing (a maximum of four
simultaneous videos were played for this test). Then the data transfer drops off and the rate
becomes very marginal. The graph in Figure 10 only shows the average bandwidth consumed
during the intial data spike.
When the Branch Repeater is introduced into the environment, the spike in data transfer time was
reduced by the amount of data transferred during the spike and the duration the spike appeared.
The bandwidth consumption for this standard WMV file with Branch Repeater spiked in the first 10
to 30 seconds and then remained below 10 kbps for the remainder of time the video played. The
average bandwidth consumed for the WMV file with native XenDesktop was approximately 464
kbps during the data spike; whereas, the average bandwidth consumed for the WMV file with
Branch Repeater was approximately 148 kbps, a reduction of 68%. The average bandwidth
measurements only focused on the data spike timeframe rather than the entire video play time to
provide a better representation of the actual data transfer rate required.
0 200 400 600
MediaStream for Native XenDesktop
MediaStream for XenDesktop with
Branch Repeater
Avg Bandwidth per Video (kbps)
Video Workflow - Standard WMV

Figure 11: Video Workflow-Average Bandwidth Consumed per Video
HDX MediaStream for High Definition WMV
The High Definition WMV file required more bandwidth than the standard T1 connection used for
all other test scenarios to transfer the data to the user device for rendering. To provide the best
possible bandwidth guidance for a High Definition video, it was determined that the WAN
connection would be increased from 1.5 mbps to 10 mbps for the HD video testing to ensure that
the effective amount of available bandwidth was greater than the 6.5mbps data rate of the video.
The latency and the packet loss were still consistent with 80ms roundtrip latency and 1% packet loss.
The HD video was fetched on the server-side and rendered on the client. This configuration allows
the video to be sent to the end-user device in its native format versus sending frame updates.
If the remote user had a connection lower than the default threshold of 524kbps for client side
rendering of HDX MediaStream for Windows or was unable to utilize the local client resources for
video rendering, then the HD video would render within the virtual desktop on the server and send
individual frames across the WAN connection to ensure that the user could still see the video and
access the virtual desktop although the quality would be degraded.
Unlike the standard video, the data transfer was high for the entire duration of the video. Only
when the Branch Repeater was introduced into the environment did the data transfer spiked at the
beginning of the video and then remainded marginal for the remainder of time that the video played.
This is mentioned because the average bandwidth consumed for the HD WMV file with native
XenDesktop was approximately 1812 kbps during the entire video; whereas, the average bandwidth
consumed for the WMV file with Branch Repeater was approximately 206 kbps with a data spike
only for a brief moment at the start of the video. These numbers show that introducing a Branch
Repeater solution into a high definition WMV video environment would show approximately 89%
reduction in the average amount of bandwidth consumed per HD video.
0 500 1000 1500 2000
MediaStream for XenDesktop with
Branch Repeater
MediaStream for Native XenDesktop
Avg Data Throughput per Video (kbps)
Video Workflow - High Definition Video

Conclusion
In conclusion, this paper provides customers with guidance for determining the amount of
bandwidth required to transition branch office employees from a local desktop to a virtual desktop
hosted on Citrix XenDesktop. The graph shown in Figure 12 provides a collective representation of
all the average bandwidth requirements discussed in this document.
Figure 22: Average Bandwidth Consumed per Session
When reviewing the test results represented in Figure 12 and integrating those results into a unique
customer environment, the following key topics should always be considered for any bandwidth
assessment exercise:
1. The process for determining the bandwidth requirements for a XenDesktop solution in a
branch office should always start with having a good understanding of the applications and
current network demand that the branch office employees have on the existing WAN
connection. The application specific bandwidth numbers in this document should provide
guidance for common applications, but more intricate applications such as a CRM or ERP
system should be thoroughly evaluated before making any conclusions regarding WAN
requirements.
2. WAN utilization is another key component to consider when evaluating the WAN
connection. When assessing WAN utilization, it should not be assumed that the average
bandwidth consumed for all users should consume 100% of the available bandwidth. If
possible, the virtual desktop performance should be measured when the WAN connection is
congested to determine the acceptable overall percent of average WAN utilization before
user performance is impacted. To ensure that enough bandwidth is available, the maximum
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Office Internet
Explorer
Printing:
Word
Printing: PDF Flash Video
(server
rendered)
Standard
Video
High
Definition
Video
kbps
Average Bandwidth Consumed per Session
Native XenDesktop XenDesktop & Branch Repeater

WAN utilization must be based on the most network intensive time of the day and the
effective available bandwidth.
3. Although sometimes difficult to predict, future users and application changes can also affect
the bandwidth requirements sooner than expected. The WAN connection selected should
have the potential for company growth without hindering existing user experience.
4. The other key factor when looking to optimize an existing or future WAN connection as
predominantly shown throughout this paper is the introduction of a Citrix Branch Repeater
solution into any branch office environment. As repeatedly shown throughout the results in
this document, the Citrix Branch Repeater can optimize a WAN connection, improve the
overall user experience, and potentially double the amount of users on an existing WAN
connection.

Appendix A - Hardware and Software Configurations
The Consulting Solutions lab located in Fort Lauderdale, Florida provided the following hardware
and software for this report in conjunction with our partnership with Login Consultants:
Component Operating system Hardware
XenServer Pool Hosting
Virtual Desktops
XenServer 5.5.0 4 physical HP DL360G5
2x Dual Core 2.66 Hz Intel Xeon
Proc, 16GB RAM, 2x72GB hard
drives
XenServer Hosting
Infrastructure
XenServer 5.5.0 HP DL360G5
drives
XenServer Hosting
XenDesktop Environment
drives
XenServer Hosting
Branch Office Environment
drives
Component Operating system Hardware
Login VSI File Share Windows Server
2003 R2 SP2
HP DL360 G5 2.5Ghz Intel Xeon
Proc, 1GB RAM, 1x72GB hard drive
Branch Repeaters Version 5.5.1
Build 58.191613
Model 8520 (pair)
Apposite WAN Emulator Version 4.0.1 Apposite Linktropy Mini
Table 4: Physical Hardware
Virtual Component Operating system Virtual Hardware
Virtual Desktops Windows XP SP3 1GB RAM, 1 vCPU
SQL Server Windows Server 2008 2GB RAM, 2 vCPUs
Active Directory Windows Server
2003 R2 SP2
1GB RAM, 1 vCPU
Citrix License Server Windows Server 2008 1GB RAM, 1 vCPU
Citrix Provisioning Services Windows Server
2003 R2 SP2
1GB RAM, 1 vCPU
Citrix Delivery Controller
with Web Interface
Windows Server
2003 R2 SP2
2GB RAM, 2 vCPUs
Login VSI Launcher Windows Server
2003 R2 SP2
4GB RAM, 2 vCPUs
Print Server Windows Server
2003 R2 SP2
1GB RAM, 1 vCPU
Table 5: Virtual Hardware

Software Version
Login VSI Pro Version 2.0
Microsoft Office Office 2007 SP1
Microsoft SQL Server SQL Server 2005
Citrix XenDesktop Version 4
Citrix Provisioning Services Version 5.1.1.2950
Internet Explorer Version 7
Windows Media Player Version 11
Real Player Version 1.0.5
Build 12.0.0.343
Table 6: Software Applications used in the report
Appendix B - Citrix XenDesktop Configurations
Property Setting
Farm-Wide Properties
Connection Access Controls Any Connection
Desktop Delivery ControllerSession Reliability Disabled
ICAAuto Client Reconnect Reconnect automatically
ICAKeep-Alive 60 seconds
HDXBrowser Acceleration Browser Acceleration: Enabled
Image Compression levels: Medium
Variable Image compression: Enabled
Flash Enable Adobe Flash Player
Desktop Group Properties
BasicAssignment Type Pooled
AdvancedClient Options Colors: True Color (24-bit)
Connection:
Encryption; 128-Bit Login Only (RC-5)
Connection Protocols: ICA
AdvancedLogoff Behavior Restart the virtual desktop
Citrix Policies
BandwidthVisual EffectsTurn off menu animation Enabled - Turn off Menu and Window Animations
BandwidthVisual EffectsTurn off window content
while dragging
Enabled - Turn off window content while dragging
SpeedScreenImage acceleration using lossy
compression
Enabled
Compression level: Medium compression; good
image quality
Session LimitsCOM Ports Disabled
Session LimitsLPT Ports Disabled
Session LimitsOEM Virtual Channels Disabled
Session LimitsTWAIN Redirection Disabled
Client DevicesResourcesAudioMicrophones Enabled - Use client microphones for audio input
Client DevicesResourcesAudioSound Quality Enabled – Medium sound quality; good
performance

Client DevicesResourcesDrivesConnection Enabled – Connect Client Drives at Logon
Client DevicesResourcesDrivesMappings Enabled
Turn off Floppy disk drives
Turn off CD-ROM drives
Turn off Remote drives
Client DevicesResourcesOptimizeAsynchronous
writes
Enabled – Turn on asynchronous disk writes to
client disks
Client DevicesResourcesPortsTurn off COM
ports
Enabled – Turn off client COM ports
Client DevicesResourcesPortsTurn off LPT ports Enabled – Turn off LPT ports
Client DevicesResourcesPDA Devices Disabled
Client DevicesResourcesOtherTurn off OEM
virtual channels
Enabled – Turn Off OEM Virtual Channels
Client DevicesMaintenanceTurn off auto client
update
Enabled – Turn off Client Update
PrintingClient PrintersAuto-creation Enabled – Auto-create the client’s default printer
only
PrintingClient PrintersLegacy client printers Disabled
PrintingDriversUniversal driver Enabled – Use universal driver only if requested
driver is unavailable
SecurityEncryptionSecureICA encryption Enabled –RC5 (128-bit) logon only
Appendix C – Citrix Branch Repeater Configurations
Property Setting
Bandwidth Management>Status Softboost
Bandwidth Management>Bandwidth
Scheduler>Bandwidth Consumption
Full Bandwidth
Scheduler>Bandwidth Limit (Send):
1425kbps
Scheduler>Bandwidth Limit (Receive)
1425kbps
Service Class Policy>ICA Accelerate
Disk based Compression
Service Class Policy>HTTP Accelerate
Disk based Compression
Appendix D – Login VSI Pro Configurations
Property Setting
VSI Launcher Configuration
Type of connection Custom with CSV
User Credentials NA
Number 1 to n (Varied based on workflow)

Interval Custom
Custom Command line Custom
Location of csv file File Share Path (datacenter)
Auto log off No
VSI Workflow
Office 2007 Customized MEDIUM workflow to execute Office
only – VSI Pro Feature
IE 2007 Customized to run CORE workflow that executes
custom AutoIT based IE browsing script – VSI Pro
feature
Video Customized to execute Flash, standard WMV, and
HD WMV video
Appendix E – HDX MediaStream Active Directory GPOs
HDX MediaStream for Flash is enabled or disabled through Active Directory Group Policy Objects
(GPOs). The Citrix support provides two ADM templates that can be imported into the
environment: HDX-Flash-Client and HDX-Flash-Server. Both of these templates are found on the
XenDesktop 4 media in the W2K3EnSupportConfiguration folder.
Once the HDX-Flash-Client and HDX-Flash-Server ADM templates were imported into the GPO
that applied to the XenDesktop test users, the following settings were made:
 Enable HDX MediaStream for Flash on the user device: Enabled
 Enable server-side content fetching: Enabled
 Enable HDX MediaStream for Flash for connections to the server: Enabled
 Server-side content fetching list: Enabled and set to * so all URLs would be fetched
Appendix F - References
Login Consultants’ Login VSI Pro Benchmarking Tool:
http://www.loginvsi.com
Citrix HDX Technologies:
http://hdx.citrix.com
High Definition Windows Media Video (robotica.wmv):
http://www.microsoft.com/windows/windowsmedia/musicandvideo/hdvideo/contentshowca
se.aspx
HDX MediaStream for Flash Information:
http://www.citrix.com/tv/#videos/635
HDX MediaStream GPO Configurations:

http://support.citrix.com/proddocs/index.jsp?lang=en&topic=/xenapp5fp2-w2k3/hd-flash-
configure.html

Revision Change Description Updated By Date
0.1 First draft Bhumik Patel & Carisa Stringer January 22, 2010
0.2 QA Paul Wilson January 28, 2010
0.3 Update Bhumik Patel & Carisa Stringer February 10, 2010
0.4 Final Version Bhumik Patel & Carisa Stringer March 5, 2010
About Citrix
Citrix Systems, Inc. (NASDAQ:CTXS) is the leading provider of virtualization, networking and software as a service
technologies for more than 230,000 organizations worldwide. It’s Citrix Delivery Center, Citrix Cloud Center (C3)
and Citrix Online Services product families radically simplify computing for millions of users, delivering applications
as an on-demand service to any user, in any location on any device. Citrix customers include the world’s largest
Internet companies, 99 percent of Fortune Global 500 enterprises, and hundreds of thousands of small businesses
and prosumers worldwide. Citrix partners with over 10,000 companies worldwide in more than 100 countries.
Founded in 1989, annual revenue in 2008 was $1.6 billion.
©2010 Citrix Systems, Inc. All rights reserved. Citrix®, Access Gateway™, Branch Repeater™, Citrix Repeater™,
HDX™, XenServer™, XenApp™, XenDesktop™ and Citrix Delivery Center™ are trademarks of Citrix Systems, Inc.
and/or one or more of its subsidiaries, and may be registered in the United States Patent and Trademark Office
and in other countries. All other trademarks and registered trademarks are property of their respective owners.

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