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Improve the XenDesktop experience for branch and mobile workers with CloudBridgeMaintaining or improving the desktop experience for everyone is essential for a successful desktop virtualization deployment

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When implementing a desktop virtualization solution, IT must ensure that the user experience is the same or better than what employees receive through traditional, localized PC sessions. Otherwise, when the shift to the new desktop delivery method occurs, users will quickly notice any degradation in performance, which will generate complaints and potentially cause the virtualization initiative to fail.

Ensuring a satisfying experience for workers colocated with the enterprise datacenter is not a problem. However, for the remote workforce, which includes branch and mobile workers, this is more challenging because the enterprise WAN can degrade the performance of virtual desktop solutions, and the enterprise WAN is outside the control of enterprise IT.

In the following paragraphs, we discuss how the WAN affects virtualization and how the Citrix CloudBridge platform is uniquely capable of solving this challenge.

How the WAN impacts desktop and application virtualization

WAN problems are more than just the occasional disconnects commonly caused by a rogue IP address or an intermittent router. The most bothersome problems are subtle, and they add up over the duration of a virtualized desktop or application session. Users may notice that application response times lag; for example, a document that took five seconds to load an hour before now takes five minutes, even though the person remains in the same location, on the same network. When this occurs, the person typically remembers how wonderful life was under the “old way” of doing things, with all applications and desktop sessions running locally.

Desktop virtualization may lead to daily user dissatisfaction, which is not something the IT team wants to tell management. Upon digging deeper into the problem, IT quickly discovers that virtualization software is not the issue— the root cause is the WAN.

WAN latency and congestion

Virtualized desktop users are familiar with the webpage that takes forever to load or the mouse click that hangs endlessly in limbo. When users are performing highly interactive tasks across the network, fast application response time is essential to a superior experience and high productivity. Many people accept slow response times when accessing public websites but find them unacceptable when performing work-related tasks and remotely accessing the corporate network.

These delays are due to latency and congestion in the WAN. In corporate LAN networks, round-trip time (RTT) is often within tenths of a millisecond; however, over the WAN RTT can range from tens to hundreds of milliseconds

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depending on distance, network design and traffic congestion. Given this fact, it is easy to see how latency and congestion could turn a virtual desktop session into a waiting game for branch and mobile users.

Bandwidth capacity

Network bandwidth is simply the amount of data the network can transfer at any given time. The remote user feels the impact of limited bandwidth most acutely when downloading or uploading files, watching streaming multimedia or conducting other activities that require large session input/output (I/O). Each WAN link has finite bandwidth and allocates a certain amount of pipeline to each user session. The network topology (routers, servers, network software) can prioritize bandwidth on a per-user or per-application basis.

By definition, delivering virtual desktops to remote endpoints requires more bandwidth than executing local applications. In hosted desktop sessions, all elements related to desktop and application delivery reside in the datacenter and all activities, from screen updates to keystrokes, execute across the WAN. Therefore, bandwidth requirements increase in direct proportion to the number of virtualized desktop sessions.

A new factor that is increasing demands on bandwidth is video content usage within the enterprise.  In fact, Gartner forecasted that by 2016, large companies will stream more than 16 hours of video per worker, per month.1 One reason is the migration to video-based training classes aimed at reducing travel costs.   Also, to meet government requirements for routine training in certain HR topics and to communicate corporate policies on insider trading and conflicts of interest, among others, many enterprises have developed video-based classes. Marketing departments are now recording product announcements and product training classes to distribute to sales teams and partners. Enterprises are even adding internal video content sites for sharing business-related materials.

While video provides a richer training, marketing and collaboration experience, its transmission to branch and mobile workers consumes large amounts of costly WAN bandwidth and may congest the WAN pipe. Moreover, in the case of mandatory training and compliance videos, the same content is watched over and over by multiple branch employees, leading to repeated downloads. Similarly, if a popular video goes viral within the enterprise, the same files will traverse the WAN link from server to branch multiple times. These scenarios result not only in a poor viewing experience but also in slower response time for office-critical applications such as email.

Inefficient and “chatty” protocols

When a desktop and applications run as a client on remote endpoints, application protocols can also affect WAN performance. Some non-virtual (native) applications require significant communication overhead beyond a simple “request/acknowledge.” For example, consider common word processing, presentation and spreadsheet tools. The default protocol used for file sharing is the Common Internet File System (CIFS), which requires considerable back-and-forthhandshaking between the endpoint system accessing the file and the datacenter-based server hosting it.

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In addition to transferring the file, using the application requires multiple handshakes across the network. Every handshake incurs delays—from the user interactions, to the server host processing the request, to the network latency. And they all add up to degrade the user experience.

With the rise of Microsoft SharePoint and similar collaboration software, users may need files hosted as part of a master consolidation and centralization initiative. All files and documents are stored at a datacenter, while users are sitting at a branch office or at home or possibly at a public Wi-Fi hotspot. When users access these files, the back-and-forth handshaking of chatty protocols including MAPI, FTP and NFS can affect not only their own experience but also that of every other branch worker on the network—thus compounding the problem.

Why traditional methods for ensuring the user experience fall short Adding bandwidth

When trying to solve a branch or mobile user experience challenge raised by virtualization, the most common approach by an IT team is simply to add more bandwidth. However, mobile users working from wireless hotspots or home often have no choice but to endure bandwidth and latency issues because they are beyond the control of the organization. Clearly, the local coffee shop is unlikely to invest in higher-capacity trunking for the roaming road warrior.

Branch offices also present a dilemma for IT. In most cases, the branch office resides on a leased network trunk shared with other businesses, and connects to the corporate datacenter across the WAN. Multiple users and applications compete for the same bandwidth. In this scenario, IT must make a trade-off between user experience and cost of the shared network trunk. Adding more bandwidth means higher cost of ownership, delaying some of the ROI benefits associated with desktop and application centralization.

Adding branch office servers

Alternatively, IT may decide not centralize everything at the home office datacenter. Instead, servers running certain mission-critical applications can be installed in each branch office to reduce the amount of network traffic. While this approach solves the local bandwidth problem, IT must now manage the remote servers and ensure data replication, which adds costs and detracts from the benefits of centralization, consolidation and desktop virtualization initiatives.

Still another option is to create a local virtual desktop delivery infrastructure for certain branch offices. This alternative maintains alignment with the overall corporate virtualization initiative; however, it still increases infrastructure expenses. Additionally, this approach clearly does not solve the challenge facing employees who need to work from their homes or other remote locations—the WAN is still their only connection point.

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Generic router QoS optimization

The latest-generation network routers and trunked switches support features that prioritize network traffic and improve overall quality of service (QoS). Most of these solutions are designed to prioritize some packets ahead of others, as opposed to being application aware. To obtain a deeply granular view of application traffic and differentiate an interactive desktop virtualization session from a background printing activity, a different solution is needed.

CloudBridge enhances the user experience and maximizes the value of XenDesktopCitrix specifically engineered its CloudBridge WAN optimization platform to deliver a high-definition user experience with virtual desktops and apps hosted and delivered by Citrix XenDesktop and Citrix XenApp. CloudBridge accelerates time-consuming tasks such as printing, file downloads and page scrolling over the WAN by up to five times.

At the same time, CloudBridge reduces XenDesktop and XenApp traffic, resulting in bandwidth savings of up to 80 percent per desktop.

Figure 1: CloudBridge optimization for XenDesktop

As a result, organizations can serve up to five times more XenDesktop and XenApp users in each branch without upgrading bandwidth, as shown in Figure 1.

CloudBridge also improves the performance of video delivered within a XenDesktop and XenApp environment. By identifying, classifying and caching video content, CloudBridge significantly reduces associated WAN bandwidth demands while ensuring that business-related content is given a higher priority than other content employees may view.

For example, when a user at a branch office with a properly configured CloudBridge appliance plays a video from the video server hosted in the

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datacenter or on the public Internet, the request for video content will result in caching of that video on the local CloudBridge device. Once cached, the video will be served from the local CloudBridge appliance in response to all subsequent requests until the content is flushed or marked as stale.

Local video caching has two main advantages. First, performance is faster and video download times improve by over 45 times because the video is served at LAN speed (Figure 2). Second, WAN link usage for redundant transfers is minimized. CloudBridge video caching supports all video content transmitted over HTTP, including videos played directly within the browser or played in a XenApp/XenDesktop environment with HDX Flash redirection enabled.

Figure 2: Download times with CloudBridge video caching

CloudBridge benefits are not restricted to XenDesktop and XenApp; Figure 3 shows the benefits it can provide to other common application protocols.

Figure 3: CloudBridge benefits many common applications

The net result is that CloudBridge accelerates the ROI and time to value associated with desktop and application centralization and virtualization, while eliminating the costs and administrative burden of adding extra branch servers or upgrading network bandwidth. IT can build a single desktop virtualization infrastructure that provides an excellent experience for all users regardless of location or network conditions.

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How CloudBridge improves the user experience

To provide a superior experience to branch and mobile users, CloudBridge combines WAN optimization features as well as Layer 2 cloud tunneling capabilities and delivers maximum functionality in a unified platform. Only CloudBridge can deliver all the following functions in one platform, either as a physical or virtual appliance:

HDX WAN optimization technology CloudBridge is engineered with intimate knowledge of the Citrix HDX protocol, the set of capabilities that work together to deliver a high-definition user experience of virtual desktops and applications. As a result, it has more HDX optimization capabilities than any other WAN optimization solution. CloudBridge can decrypt HDX streams, parse the protocol and identify specific traffic types. It can de-duplicate down to very granular commands while ensuring high priority for interactive traffic.

Application acceleration CloudBridge can prioritize mission-critical traffic to maximize WAN throughput. It can accelerate any TCP-based application, including file transfers, email, SSL, ERP, CRM, CAD, data backup and replication, and optimize Microsoft applications such as Exchange and SharePoint.

Secure cloud connectivity CloudBridge ensures complete security for data in motion between the corporate datacenter and a third-party cloud while delivering services to users on demand.

Plug-and-play for any network By immediately identifying and optimizing common enterprise traffic through remote appliance auto-discovery, CloudBridge eases network integration time. It ensures reliability and preserves TCP/IP headers, VLAN tags and QoS markings with full network transparency and multiple deployment options, such as high-availability pairs.

QoS CloudBridge guarantees QoS by assessing network usage, classifying apps and services traffic, controlling bandwidth consumption, monitoring network congestion and delays and remediating problems quickly. It can identify and prioritize delivery of virtual desktops and virtual apps to a branch office based on user group (desktop group) and published application.

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Security and data protection The Citrix solution accelerates encrypted XenDesktop and XenApp traffic and web applications while maintaining the highest levels of security. Disk compression history is encrypted using AES-256 to prevent theft of sensitive data and to comply with security mandates and regulations. CloudBridge interoperates with Citrix NetScaler Gateway appliances and the Citrix Receiver secure access plug-in to optimize all traffic within the secure SSL VPN for remote and mobile users.

Optimized video delivery Video consumption in the enterprise is expected to reach 16 hours per month per employee within a couple of years according to industry analysts.  To address the demands on the enterprise WAN created by video usage, CloudBridge now provides IT departments with a video identification, shaping and caching solution that can optimize video delivery to branch offices.

ConclusionDesktop virtualization provides a smart, highly effective way to enhance desktop productivity while securely extending corporate data to employees on the go. However, once workers move outside the corporate headquarters boundary, they are at the mercy of their WAN connectivity. Innovative WAN optimization technologies are needed to provide granular visibility into WAN traffic for prioritization, while optimizing performance where it counts the most.

Citrix engineered its CloudBridge WAN optimization platform to deliver a high-definition user experience for XenDesktop and XenApp. CloudBridge accelerates time-consuming tasks such as printing, file downloads and page scrolling by up to five times, with a corresponding decrease in WAN bandwidth. With new video delivery optimization enhancements, CloudBridge can reduce video traffic by a factor of 45. In addition to these benefits, enterprise IT can simplify branch office infrastructure by selecting a CloudBridge branch office appliance with an integrated Windows Server.

To learn more about CloudBridge and its benefits, please visit http://www.citrix.com/products/cloudbridge/overview.html or contact a Citrix sales representative.

About CitrixCitrix (NASDAQ:CTXS) is the cloud company that enables mobile workstyles—empowering people to work and collaborate from anywhere, easily and securely. With market-leading solutions for mobility, desktop virtualization, cloud networking, cloud platforms, collaboration and data sharing, Citrix helps organizations achieve the speed and agility necessary to succeed in a mobile and dynamic world. Citrix products are in use at more than 260,000 organizations and by over 100 million users globally. Annual revenue in 2012 was $2.59 billion. Learn more at www.citrix.com.

Copyright © 2013 Citrix Systems, Inc. All rights reserved. Citrix, CloudBridge, XenApp, XenDesktop, NetScaler Gateway, Citrix Receiver and HDX are trademarks of Citrix Systems, Inc. and/or one of its subsidiaries, and may be registered in the U.S. and other countries. Other product and company names mentioned herein may be trademarks of their respective companies.

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