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Evaluating remote desktop WAN optimization

In part four of our virtual desktop toolbox series, we explain how to improve virtual desktop performance over a WAN, including software and hardware options that boost performance.

Desktop virtualization promises to save enterprises from rising data center costs and management headaches. IT administrators, however, have had to contend with immature technology, inconsistent terminology and executive and user reluctance. Fortunately, you can get the most out of virtualization by assembling a toolbox of assorted technologies.





WAN optimization/application delivery tools

Ten years ago, I was a lowly Citrix consultant, dreaming of a time when Internet bandwidth would be both ubiquitous and unconstrained. So, what happened?

Well, even in 2011, Internet bandwidth is neither ubiquitous, nor unlimited. We still have to consider all the things we've been dealing with in the past 10 years for desktop and application virtualization: architectures, bandwidth, protocols, user locations and WAN optimization. Game on!

Framing the WAN optimization conversation

Do you know the best way to minimize the impact that a slow wide area network (WAN) has on your desktops and applications? It's actually quite simple: Don't do anything that requires a WAN.

Now, while that statement might seem like a cruel joke, there's actually a lot of truth in it. Does a slow network connection really matter if you're using locally installed applications running on a traditional laptop computer? Nope. Not one bit.

So, when you're thinking about desktop and application virtualization, keep in mind that each of these terms describes several different technologies, some of which run locally on the client, and others that run in data centers. Keep this in mind when dealing with a particularly tricky WAN-related scenario, like a high-latency or low-bandwidth connection. The best way to address it might be to just run the desktop or application locally on the client device. (There are many ways to do that -- client-based VMs, client hypervisors, client-side app virtualization, etc.)

But if the data center is a must…

Of course, you don't always have the luxury of pushing the execution of the desktop or application out to the client device. There are several scenarios where you absolutely must deal with data center execution. For example, maybe you have security requirements that prohibit real data from leaving the secure walls of the data center. Or maybe your users need to quickly switch between multiple client devices and instantly pick up right where they left off. Or maybe you have the classic data center-based computing situation, where you have "fat" three-tier applications that just don't perform well over the WAN.

For any of these cases, you need to run your desktop or application in the data center and provide remote access to it via a remoting protocol, like Microsoft Remote Desktop Protocol (RDP) or Citrix HDX. So, how do you deal with the WAN in those scenarios?

There are actually quite a few approaches you can take. The first step is to just try the application and see how it performs. You might be surprised.

If the app isn't running as smoothly as you'd like, the next step is to figure out what aspect of the network is limiting you. Do you have a bandwidth constraint? Or is your latency too high? Or maybe you're dealing with packet loss? (We don't have the room here to explain exactly how to troubleshoot your connection, but I wrote a fairly comprehensive guide to troubleshooting network performance issues with remote display protocols in 2004. Check it out -- it's still 100% relevant today.

Dealing with the bad WAN

Once you work out what your network limitation is, there are several things you can do to deal with it.

If your problem is simply limited bandwidth, you need to do whatever you can to minimize the amount of bandwidth your remote session consumes. This can be as simple as lowering the resolution, color depth or audio quality of your remote session. If you're using RDP, you could consider using a more advanced protocol -- like Citrix HDX, Quest Software's Experience Optimization Protocol (EOP) or Ericom Blaze, which includes features such as image compression and multimedia redirection to minimize the amount of data that moves across the wire.

If you have a problem with latency, try Quest EOP, Wyse Technology's Virtual Desktop Accelerator or Ericom Blaze. These software products employ various tricks (such as multiple TCP session streams) to minimize the effects of high latency.

And if packet loss is your problem, a company called iPeak Networks has a great offering that applies something like RAID 5 to network packets.

Finally, there are a lot of hardware products that can help speed the performance of remote applications and desktops. Citrix offers its Branch Repeater, and traditional WAN acceleration vendors such as Expand Networks and Riverbed Technology also sell products that address RDP and HDX traffic.

Even if you must run your desktop or application in a remote data center that will then be accessed across a slow WAN, you still have several options to choose from if the performance is not quite where you want it to be.

Read parts five and six of the desktop toolbox series:

Brian Madden is an independent industry analyst and blogger, known throughout the world as an opinionated, supertechnical desktop virtualization expert. He has written several books and more than 1,000 articles about desktop and application virtualization. Madden's blog, BrianMadden.com, receives millions of visitors per year and is a leading source for conversation, debate and discourse about the application and desktop virtualization industry. He is also the creator of BriForum, the premier independent application delivery technical conference.

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