Tim Greene over at Network World has just posted a great article titled The ABCs of WAN Optimization Savings. The article walks through the various functions of today's WAN optimization devices and how these technologies add up to big savings for IT. Citrix is singled out in the article for our dominance in speeding up virtual desktops and applications, something we have offered since delivering ICA acceleration with Branch Repeater 5 back in February.

As part of the HDX technology framework, Branch Repeater includes a suite of WAN optimization technologies that have been adapted for virtual environments. Since the underlying WAN optimization technologies are discussed in the Network World article, I will explain how Branch Repeater is unique in applying these to accelerate and optimize virtual desktops and applications.

Compression and caching - By default, XenApp compresses all ICA traffic to optimize individual user sessions. Branch Repeater automatically negotiates with XenApp to disable the native ICA compression in order to cache common graphics and data locally in the branch and compress traffic across multiple user sessions. Branch Repeater is the only WAN optimization solution that can inspect the ICA virtual channel to help determine whether to store cached data objects in memory or on disk. This helps to minimize latency for interactive traffic (screen updates, mouse movements) while maximizing compression ratios for bulk transfers within ICA (printing, file transfers).

TCP acceleration - Like any TCP-based traffic, ICA performance can suffer due to high latency and packet loss common on long distance WAN connections. Branch Repeater overcomes these issues with adaptive TCP flow control that senses these conditions and responds by optimizing TCP behavior.

QoS and traffic prioritization - In many networks, ICA shares the wire with other bandwidth hungry applications. Network congestion can 'starve out' ICA traffic causing slow and inconsistent performance. Branch Repeater prioritizes traffic and allocates bandwidth to ensure reliable, high-performance for virtual desktops and applications. However, not all data transmitted within ICA should receive equal priority. For instance, interactive screen data should be prioritized above print jobs. To address such conflicts, Branch Repeater provides the only ICA-aware QoS engine that can granularly allocate bandwidth based on virtual channel priority tags.

Branch Repeater ICA acceleration goes beyond optimizing each of these core technologies for virtual desktop and application delivery. Virtual environments tend to be far more dynamic and flexible than traditional enterprise applications. For this reason, Branch Repeater is fully integrated with XenApp and other HDX technologies to apply the right mix of optimizations for every scenario over any network. And since many of the techniques involve peering inside the ICA session, Branch Repeater works with native ICA encryption (Basic and Advanced RC-5) so there is no compromise to end-to-end security.

The Network World article wraps up by suggesting that businesses consider WAN optimization gear when deploying new applications. Rolling the cost of WAN optimization into a larger IT project - such as desktop virtualization - can be a cost-effective way to pay for the solution. So if you are considering deploying virtual desktops (VDI) in your organization, be sure to include Branch Repeater as part of your plans.

Take this quick survey to tell us more about the solutions your organization uses to optimize your WAN. 

HDX MediaStream does a fantastic job of reducing the network bandwidth requirements for streamed video compared with rending the video on the server. When using HDX MediaStream your bandwidth requirements roughly equal the bit rate of the source video file. For lower quality clips, like those found on YouTube, this is around 256Kbps. For full HD content the bandwidth requirements can be as high as 8Mbps.

While this works great over a high speed LAN, trying to push that amount of data over typical branch office T-1 is another story. This problem is magnified even more when you have multiple users in the branch office who are repeatedly pulling down the same video content. In this situation, the video quality suffers and other business applications can be impacted. This issue has nothing to do with XenApp or XenDesktop. It is purely a function of the size of video file and the limited amount of available network bandwidth.

What can you do about this? Well if the culprit is the latest viral video making its way around the Internet you could attempt to block access to sites like YouTube. However, what if the video is for legitimate business purposes? I talked to one customer at Synergy who is rolling out a corporate compliance training video to their entire company using XenApp but is worried about the impact to network bandwidth.

Enter Citrix Branch Repeater and HDX IntelliCache. With Branch Repeater 5 we now participate in the ICA session and accelerate the ICA virtual channel used by HDX MediaStream. The first time the video is streamed to the branch office, Branch Repeater caches the content locally. The next time the video is requested, Branch Repeater serves the content from its local cache rather than pulling it across the WAN. Using branch caching, you can reduce the bandwidth requirements for on-demand videos by up to 90%.

Don't just take my word for it. You can see a demo if this in action on the latest edition of Brian Madden TV. (If you don't want to watch the entire episode you can jump ahead to 5:49 into the clip).

Does the Citrix HDX story still elude you? Here's a whiteboard approach.

Let me know if this helps.

Michael

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