Virtual desktop White Paper How fast is my virtual desktop? Delivering a high definition desktop experience to branch office users with Citrix Branch Repeater DVI www.citrix.com
Executive summary Emerging technologies such as desktop and application virtualization continue to deliver on the promise of reducing IT costs and simplifying IT infrastructure. Virtualization separates the use of the applications and desktops from where they are hosted and maintained, which lowers costs because IT does not have to deploy desktops on the endpoint-computing device. Users continue to get full functionality. Unfortunately, high latency and low bandwidth Wide Area Network (WAN) connections often cause poor desktop performance for branch office users, which degrades the user experience and productivity. Citrix Branch Repeater helps organizations mitigate WAN problems and realize the full benefits of desktop virtualization throughout the organization. By providing breakthrough Citrix HDX technologies for the branch office, Branch Repeater dramatically reduces branch IT costs while providing a high definition experience that boosts the productivity of branch office users. Introduction Trade off between user experience and TCO payoff Virtualization is rapidly changing the application and desktop landscape for IT. Traditional desktop deployment requires installing, managing and supporting applications on each endpoint device. This leads to an endless cycle of updates, upgrades and security patches for resource-strapped IT personnel. Desktop virtualization solves these challenges by centralizing management and deployment. This dramatically reduces IT costs and eliminates redundant IT efforts in the enterprise. As shown in Figure 1, IT managers today are grappling with balancing the quality of the desktop experience with cost of desktop ownership. With over 55 percent of office and task workers in branch office locations, the branch office has become a key driver of organizational productivity. Branch office users expect the same level of user experience with virtual desktops and applications as they do with local desktops. High latency, low bandwidth WAN connections often significantly affect the delivery of applications and data including virtual desktops and applications. Users are plagued with slow printing, file downloads and unreliable video performance, which degrades branch user productivity. 2 Figure 1: Trade-off between user experience and TCO payoff
Virtual desktop White Paper As shown in Figure 2, many organizations have tried solving these problems by: Increasing network bandwidth at the branch offices as users and WAN traffic grow Deploying dedicated virtual application or and desktop delivery server farms at branch offices to overcome the limitations of application delivery over the WAN Continuing to maintain traditional desktop and application delivery and management methods for the branch office users Maintain a traditional application and desktop delivery Deploy dedicated virtual application or desktop farm at branch office Continue to experience slow virtual desktop performance Add more bandwidth Figure 2: Alternatives to solving virtual desktop/application delivery problems All of these approaches can dramatically increase IT expenses. Upgrading bandwidth increases monthly operational expenditures while ignoring key factors of poor performance such as inherent latency of the WAN connections. Deploying dedicated server farms at branch offices forces organizations to manage and back up multiple application and desktop farms, thus preventing them from fully realizing the cost benefits of centralized desktop and application hosting. IT managers need a solution that can provide branch office users with the same level of business agility and productivity as experienced by headquarters users, as well as the same user experience provided by traditional physical applications and desktops. Such a solution should not only reduce IT expenses in the short term, but also accelerate the ROI associated with desktop and application virtualization by being part of a flexible and adaptable end-to-end IT infrastructure from the datacenter to the desktop. Key criteria that IT managers should consider when evaluating potential solutions include: Native integration with virtual desktops and applications, so that minimum changes are required to the underlying IT infrastructure when business needs grow and change Virtual desktop and application fluency, providing IT managers with visibility and control of their desktop and application traffic Fast and reliable access to desktops and applications, providing a high definition user experience at the branch office Seamless orchestration with other components in the end-to-end application delivery infrastructure 3
Branch Repeater Delivering a high definition desktop experience to branch office users As more users deploy Citrix XenDesktop across the WAN, Citrix HDX technologies operating in the datacenter, across the network and on endpoint devices allow XenDesktop to deliver the best possible application experience for users connecting over high latency, low bandwidth connections. Branch Repeater adds groundbreaking multi-user optimizations to HDX Broadcast and HDX IntelliCache dramatically increasing XenDesktop performance for multi-user branch offices and delivering a high definition user experience. Adaptive and seamless integration with desktop virtualization Branch Repeater integrates seamlessly with XenDesktop, requiring minimal changes to the underlying infrastructure. IT managers who have already deployed or are in the process of deploying desktop virtualization technology to their branch users do not have to change client or server settings. The results are reduced IT overhead and management costs. Adaptively orchestrating with XenDesktop, Branch Repeater provides the best desktop acceleration for any user over any network. For example: Branch Repeater communicates directly with the XenDesktop agent and offloads native ICA compression. This ensures maximum possible compression and prevents the data from being compressed twice a condition that can actually increase the size of the compressed payload and introduce additional latency. No changes are required to the XenDesktop agent compression settings, so IT managers can still leverage the benefits of native XenDesktop compression for users not leveraging Branch Repeater technology. Branch Repeater automatically decrypts and encrypts XenDesktop traffic on the fly. IT managers do not need to compromise on security by disabling encryption settings on the XenDesktop agent or the client. All traffic is secure end-to-end from the datacenter to the desktop. Desktop acceleration and fluency Branch Repeater inspects and examines all XenDesktop sessions, thus providing an unprecedented level of desktop acceleration and fluency. Visibility into traffic flows carried over different virtual channels (print traffic, interactive traffic or file downloads) is a key factor in determining how and when to accelerate virtual desktops and applications to the branch user. Branch Repeater provides several network-level optimizations for HDX Broadcast resulting in consistently high performance for XenDesktop over any network: 4 Adaptive compression Branch Repeater compresses and de-duplicates all XenDesktop traffic, achieving compression ratios up to 30:1 and dramatically reducing bandwidth usage. Depending on the traffic, Branch Repeater dynamically selects between its five different compression engines to compress data at the byte, pattern and data chunk level using hardware cache memory algorithms, pattern-level software compression and data chunk matching of up to several hundred megabytes per compressed token.
Virtual desktop White Paper Using advanced de-duplication technologies, Branch Repeater transmits only changes for previously delivered data. Leveraging its unique visibility into virtual desktop traffic, Branch Repeater adaptively uses disk-based compression for heavier workflows such as print and file downloads while using memory-based compression for lighter workloads such as interactive traffic. Branch Repeater provides tangible benefits for individual desktop workflows: 6 times less bandwidth for printing 24 times less bandwidth for file transfers 25 times less bandwidth for client-side rendered video 9 times less bandwidth for server-side rendered video The result is up to 25 times less bandwidth usage per desktop user in the branch office as shown in the figure below. Bandwidth 3X-25X less bandwith per desktop VMWare View XenDesktop XenDesktop without with Branch Repeater Branch Repater Figure 3: Bandwidth savings with Branch Repeater Adaptive TCP flow control and adaptive protocol acceleration Branch Repeater mitigates latency performance penalties at the TCP and application protocol levels. For example, Branch Repeater provides a specific protocol optimization engine that adaptively orchestrates with the XenDesktop agent. As part of this process, the XenDesktop agent disables its internal Bandwidth Estimator and TCP optimizations when users can leverage Branch Repeater, offloading this functionality to Branch Repeater. The result is superior XenDesktop performance supporting more desktop users over existing bandwidth and faster workflows such as printing, file access and video playback, particularly over network links with extreme latency (e.g., satellite) or variable latency and jitter. 5
Prioritization and quality of service (QoS) As depicted in Figure 4, Branch Repeater s QoS feature provides the unique ability to classify and prioritize not just virtual desktop traffic but also discrete workflows that exist within individual XenDesktop sessions. Branch Repeater dynamically queues and prioritizes discrete traffic flows within the ICA protocol based on priority tags embedded within the ICA framing header: 0 = high, real time (e.g., video) 1 = medium, interactive (e.g., mouse movements) 2 = low, bulk transfer (e.g., file transfer) 3 = background (e.g., print) Without Citrix Branch Repeater With Citrix Branch Repeater Bulk Transfers Recreational Interactive ICA 25% 15% 60% { { Interactive ICA Recreational Bulk Transfers Figure 4. Branch Repeater QoS This priority queuing QoS engine is automatically enabled when the appliance detects traffic congestion and protects the bandwidth reserved for business-critical applications. IT managers can provide a higher priority to XenDesktop traffic flows that are mission critical such as interactive traffic (screen refreshes and mouse movements) while assigning a lower priority to workflows such as file downloads or printing. Citrix end-to-end application delivery orchestration Branch Repeater works in concert with the entire end-to-end application delivery system to apply the right mix of optimization technologies for each situation. This provides IT managers an end-to-end delivery framework, not just an isolated optimization solution for XenDesktop ICA acceleration. It involves sensing the underlying capabilities in the datacenter, network and endpoint devices then dynamically applying the best combination of HDX technologies to ensure a high definition user experience. Optimized delivery of on-demand video HDX MediaStream allows XenDesktop to transfer raw video files, such as Windows Media files, over the WAN depending on GPU capabilities and codecs supported by the client. Branch Repeater works in concert with HDX MediaStream technologies to accelerate on-demand video files, such as podcasts, online training and retail store advertisements. Acceleration of native applications Branch Repeater accelerates all TCP-based traffic and provides application-specific accelerators for the most commonly deployed and troublesome applications delivered outside of XenDesktop such as Windows file sharing, Microsoft Exchange e-mail and Microsoft SharePoint. 6
Virtual desktop White Paper Integrated Windows services Branch Repeater with Windows Server further enhances branch optimization and consolidation by including a full-function Windows Server along with Citrix HDX technology for the branch. Branch Repeater with Windows Server consolidates essential services that must remain in the branch office such as file, print, Active Directory (Domain Controller), Domain Name System (DNS) and Dynamic Host Configuration Protocol (DHCP). The approach eliminates the need for additional dedicated servers in the branch office. Conclusion Delivery of desktops over the WAN to branch users presents challenges to IT managers. As with other styles of remotely accessing centralized applications, delivering virtual desktops involves conquering common WAN challenges such as limited bandwidth, high latency, congestion and packet loss. IT organizations can mitigate these challenges by implementing a comprehensive approach to branch optimization with network-level optimizations that tightly and natively integrate with the end-to-end application delivery infrastructure. Citrix Branch Repeater offers a comprehensive solution for XenDesktop that seamlessly and adaptively orchestrates with the datacenter, network and endpoints, accelerates desktops by dramatically reducing bandwidth while supporting more users, and delivers a high definition user experience to globally distributed users. 7
Worldwide Headquarters Citrix Systems, Inc. 851 West Cypress Creek Road Fort Lauderdale, FL 33309, USA T +1 800 393 1888 T +1 954 267 3000 Americas Citrix Silicon Valley 4988 Great America Parkway Santa Clara, CA 95054, USA T +1 408 790 8000 Europe Citrix Systems International GmbH Rheinweg 9 8200 Schaffhausen, Switzerland T +41 52 635 7700 Asia Pacific Citrix Systems Hong Kong Ltd. Suite 6301-10, 63rd Floor One Island East 18 Westlands Road Island East, Hong Kong, China T +852 2100 5000 Citrix Online Division 6500 Hollister Avenue Goleta, CA 93117, USA T +1 805 690 6400 www.citrix.com 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. Its 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, XenDesktop, HDX, Branch Repeater 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. 0110