Performance Assessment and Bandwidth Analysis for Delivering XenDesktop to Branch Offices

Transcription

1 WHITE PAPER Citrix XenDesktop and Branch Repeater Performance Assessment and Bandwidth Analysis for Delivering XenDesktop to Branch Offices Citrix XenDesktop and Branch Repeater Performance Analysis

2 Contents Executive Overview... 3 Product Overview... 5 Test Environment... 7 Test Methodology... 9 Performance Results and Analysis Conclusion Appendix A - Hardware and Software Configurations Appendix B - Citrix XenDesktop Configurations Appendix C Citrix Branch Repeater Configurations Appendix D Login VSI Pro Configurations Appendix E HDX MediaStream Active Directory GPOs Appendix F - References Page 2

3 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. Page 3

4 Workflow Avg User Load Office 20 Internet Browsing Printing 1 (5MB MS Word & PDF) Flash Video (server-rendered) Standard WMV Video (client-rendered) High Definition WMV Video 2 (client-rendered) Environment Native XenDesktop XenDesktop & Branch Repeater Native XenDesktop XenDesktop & Branch Repeater Native XenDesktop XenDesktop & Branch Repeater Native XenDesktop XenDesktop & Branch Repeater Native XenDesktop XenDesktop & Branch Repeater Native XenDesktop XenDesktop & Branch Repeater Avg Bandwidth Consumed 43 kbps 31 kbps 85 kbps 38 kbps kbps kbps 174 kbps 128 kbps 464 kbps 148 kbps 1812 kbps 206 kbps 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. Page 4

5 Product Overview Citrix XenDesktop Citrix XenDesktop is a desktop virtualization solution that delivers Windows desktops as an ondemand 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. Page 5

6 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 Page 6

7 POWER STATUS CONSOLE MGMT LAN A LAN B T E C H N O L O G I E S 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 Virtual Desktops Desktop Pool Login VSI Pro Launcher Login VSI Pro Launcher Login VSI Pro Launcher Citrix Branch Repeater LINKTROPY MINI T1, 80ms Latency, 1% Packet Loss Citrix Repeater Switch Desktop Pool Desktop Pool Login VSI File Share Citrix XenServer Citrix XenServer Citrix XenServer XenDesktop Environment Infrastructure Active Directory SQL Server Citrix License Server Citrix XenServer Print Server Delivery Controller with Web Interface Citrix Provisioning Server Citrix XenServer 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 Page 7

8 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. Page 8

9 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% Microsoft Office 2007 Workflow Table 2: Test Environment WAN Connection 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 s and PowerPoint presentations, the data gathered from the Office workflow most closely resembles a real-world customer environment. Page 9

10 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. Page 10

11 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 Page 11

12 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 serverside 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 tenminute 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. Page 12

13 Avg Bandwidth Consumed per User ( kbps) Office Workflow Users XenDesktop Average Bandwidth per User (Native) XenDesktop Average Bandwidth per User (with Branch Repeater) 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. Page 13

14 Avg Bandwidth Consumed (kbps) 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. Office Workflow Users XenDesktop Average Bandwidth (Native) XenDesktop Average Bandwidth (with Branch Repeater) 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. Page 14

15 Native XenDesktop Launch Time High WAN Congestion XenDesktop Launch Time with Branch Repeater High WAN Congestion Native XenDesktop Launch Time Low WAN Congestion XenDesktop Launch Time with Branch Repeater Low WAN Congestion XenDesktop Launch Time XenDesktop Launch Time Seconds Figure 4: Office Workflow-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. Page 15

16 Avg Bandwidth Consumed per User (kbps) 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 Internet Explorer Workflow Users XenDesktop Average Bandwidth per User (Native) XenDesktop Average Bandwidth per User (with Branch Repeater) 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 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. Page 16

17 Avg Data Bandwidth (kbps) Internet Explorer Workflow Users XenDesktop Average Bandwidth (Native) XenDesktop Average Bandwidth (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 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. Page 17

18 5MB PDF XenDesktop with Branch Repeater Printing Workflow 5MB Word XenDesktop with Branch Repeater 5MB Word Native XenDesktop 5MB PDF Native XenDesktop Total Bandwidth (KB) Total Bandwidth Figure 7: Printing Workflow-Total Bandwidth per Print Job 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. 5MB PDF XenDesktop with Branch Repeater Printing Workflow 5MB Word XenDesktop with Branch Repeater 5MB PDF Native XenDesktop 5MB Word Native XenDesktop Avg Bandwidth (kbps) Figure 8: Printing Workflow-Average Bandwidth Consumed per Document Page 18

19 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. Native XenDesktop XenDesktop with Branch Repeater Document Average Bandwidth (kbps) Time to Spool Print Job (seconds) 5MB Word 593 kbps 28s 5MB PDF 533 kbps 31s 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). Page 19

20 Video Workflow - Flash MediaStream for Flash for XenDesktop with Branch Repeater MediaStream for Flash Native XenDesktop Avg Bandwidth per User (kbps) 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. Page 20

21 Video Workflow - Standard WMV MediaStream for XenDesktop with Branch Repeater MediaStream for Native XenDesktop Avg Bandwidth per Video (kbps) 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. Page 21

22 Video Workflow - High Definition Video MediaStream for Native XenDesktop MediaStream for XenDesktop with Branch Repeater Avg Data Throughput per Video (kbps) 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. Page 22

23 kbps 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 Average Bandwidth Consumed per Session Office Internet Explorer Printing: Word Printing: PDF Flash Video (server rendered) Standard Video High Definition Video Native XenDesktop XenDesktop & Branch Repeater 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 Page 23

24 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. Page 24

25 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 XenServer Pool Hosting Virtual Desktops XenServer Hosting Infrastructure XenServer Hosting XenDesktop Environment XenServer Hosting Branch Office Environment XenServer XenServer XenServer physical HP DL360G5 2x Dual Core 2.66 Hz Intel Xeon Proc, 16GB RAM, 2x72GB hard drives HP DL360G5 2x Dual Core 2.66 Hz Intel Xeon Proc, 16GB RAM, 2x72GB hard drives HP DL360G5 2x Dual Core 2.66 Hz Intel Xeon Proc, 16GB RAM, 2x72GB hard drives HP DL360G5 2x Dual Core 2.66 Hz Intel Xeon Proc, 16GB RAM, 2x72GB hard 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 Model 8520 (pair) Build Apposite WAN Emulator Version 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 GB RAM, 2 vcpus Active Directory Windows Server 1GB RAM, 1 vcpu 2003 R2 SP2 Citrix License Server Windows Server GB RAM, 1 vcpu Citrix Provisioning Services Windows Server 1GB RAM, 1 vcpu 2003 R2 SP2 Citrix Delivery Controller Windows Server 2GB RAM, 2 vcpus with Web Interface 2003 R2 SP2 Login VSI Launcher Windows Server 4GB RAM, 2 vcpus 2003 R2 SP2 Print Server Windows Server 2003 R2 SP2 1GB RAM, 1 vcpu Table 5: Virtual Hardware Page 25

26 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 Internet Explorer Version 7 Windows Media Player Version 11 Real Player Version Build Table 6: Software Applications used in the report Appendix B - Citrix XenDesktop Configurations Property Farm-Wide Properties Connection Access Controls Desktop Delivery Controller\Session Reliability ICA\Auto Client Reconnect ICA\Keep-Alive HDX\Browser Acceleration Flash Desktop Group Properties Basic\Assignment Type Advanced\Client Options Advanced\Logoff Behavior Citrix Policies Bandwidth\Visual Effects\Turn off menu animation Bandwidth\Visual Effects\Turn off window content while dragging SpeedScreen\Image acceleration using lossy compression Session Limits\COM Ports Session Limits\LPT Ports Session Limits\OEM Virtual Channels Session Limits\TWAIN Redirection Client Devices\Resources\Audio\Microphones Client Devices\Resources\Audio\Sound Quality Setting Any Connection Disabled Reconnect automatically 60 seconds Browser Acceleration: Enabled Image Compression levels: Medium Variable Image compression: Enabled Enable Adobe Flash Player Pooled Colors: True Color (24-bit) Connection: Encryption; 128-Bit Login Only (RC-5) Connection Protocols: ICA Restart the virtual desktop Enabled - Turn off Menu and Window Animations Enabled - Turn off window content while dragging Enabled Compression level: Medium compression; good image quality Disabled Disabled Disabled Disabled Enabled - Use client microphones for audio input Enabled Medium sound quality; good performance Page 26

27 Client Devices\Resources\Drives\Connection Client Devices\Resources\Drives\Mappings Client Devices\Resources\Optimize\Asynchronous writes Client Devices\Resources\Ports\Turn off COM ports Client Devices\Resources\Ports\Turn off LPT ports Client Devices\Resources\PDA Devices Client Devices\Resources\Other\Turn off OEM virtual channels Client Devices\Maintenance\Turn off auto client update Printing\Client Printers\Auto-creation Printing\Client Printers\Legacy client printers Printing\Drivers\Universal driver Security\Encryption\SecureICA encryption Enabled Connect Client Drives at Logon Enabled Turn off Floppy disk drives Turn off CD-ROM drives Turn off Remote drives Enabled Turn on asynchronous disk writes to client disks Enabled Turn off client COM ports Enabled Turn off LPT ports Disabled Enabled Turn Off OEM Virtual Channels Enabled Turn off Client Update Enabled Auto-create the client s default printer only Disabled Enabled Use universal driver only if requested driver is unavailable Enabled RC5 (128-bit) logon only Appendix C Citrix Branch Repeater Configurations Property Bandwidth Management>Status Bandwidth Management>Bandwidth Scheduler>Bandwidth Consumption Bandwidth Management>Bandwidth Scheduler>Bandwidth Limit (Send): Bandwidth Management>Bandwidth Scheduler>Bandwidth Limit (Receive) Service Class Policy>ICA Service Class Policy>HTTP Setting Softboost Full Bandwidth 1425kbps 1425kbps Accelerate Disk based Compression Accelerate Disk based Compression Appendix D Login VSI Pro Configurations Property VSI Launcher Configuration Type of connection User Credentials Number Setting Custom with CSV NA 1 to n (Varied based on workflow) Page 27