VDI over the WAN

Arthur Cole

VDI deployments are expected to kick into high gear in the coming year, finally ushering in the promise of centralized desktop images delivered to thin clients over standard enterprise networks.

This may or may not require a network upgrade, depending on the level of throughput that is currently available in a given enterprise. Most observers say 10 GbE will be a minimum requirement, considering that VDI will be carried over the same infrastructure that handles all manner of data, which will increasingly come to include storage as network consolidation plans shake out.

But all of this begs the question: What about the wide area? Does it look like the WAN, which usually involves some sort of public backbone somewhere in the chain, will be able to handle the extra burden of virtual desktops?

Ultimately, the answer is yes, but it will take a bit of work to get there.

WAN acceleration technology is rapidly becoming the norm for application delivery out to the branch office, and many of these systems are being tailored for VDI as well. As Expand Networks explains in a recent white paper, one of the chief obstacles in accelerating VDI architectures over the WAN is the fact that most VDI platforms use server-based protocols like Microsoft Terminal Services RDP and Citrix ICA for remote access, and these generally don't mesh well with the unpredictable data environment on the WAN. Expand has countered this problem in its acceleration platform with a special plug-in that optimizes the smaller packet structure of server protocols.

Other techniques are also available, according to tech blogger Brian Madden. One of the simplest is to avoid VDI altogether for the moment in favor of some of the earlier desktop virtualization approaches. You could also opt for things like remote client management through bare-metal hypervisors or local application streaming. But even if an acceleration platform is necessary, that will still be a lot cheaper than paying for a faster WAN service.

An independent WAN optimization system may not be necessary before too long, as many of the same technologies are finding their way into the leading VDI platforms. Citrix' new XenDesktop 4, for example, has expanded its HDX module to provide for improved Flash multimedia performance while cutting bandwidth usage some 90 percent. That data reduction stretches across both the LAN and WAN and is useful for everything from webcam and VoIP services to better audio and 3D graphics.


Over in the UK, Ericom Software says it has an improved version of the Ericom Blaze Microsoft RDP acceleration and compression system that improves network performance by 25 percent and reduces bandwidth consumption 25-fold. The system is geared toward graphics-rich content like browsers and PowerPoint displays and is compatible with all RDP hosts, including Terminal Services, virtual desktops and remote workstations. The system is already available on the Itona line of Linux and Windows XP thin clients from VXL Instruments.

One of the things that VDI has going for it is that it leverages many of the changes already taking place in the data center: virtualization, high-speed networking, resource consolidation and, now, WAN optimization. And while VDI certainly looks to be a cheaper solution that traditional desktop infrastructure, the jury is still out as to whether it can provide a suitable working environment for users accustomed to their own setup.

One thing is certain, though, acceleration will go a long way toward bringing remote workers into the fold.

Add Comment      Leave a comment on this blog post
Oct 9, 2009 10:32 AM Alx Frances Alx Frances  says:

There are various organizations looking at managed services, like Akamai, that allow the internet to be a high-performance and highly available platform for the delivery of desktop & application virtualization environments as opposed to WAN or data-center build-out.

Oct 12, 2009 5:39 AM Rodd Ahrenstorff Rodd Ahrenstorff  says:

eh...10GbE?  Are you delivering full motion HD video?  I personally think this is crazy for most use cases.  Seriously, measure the amount of bandwidth required to do your job done...that is after all the reason the company provides you a 'computer' in the first place.  As I'm aware, 'most' applications are text based and they don't require anything for bandwidth.  I server 40+ users in Citrix a fully published desktop over a 1.5Mb T1 line.

Oct 13, 2009 7:37 AM Satya Vardharajan Satya Vardharajan  says:

Have you considered Citrix Branch Repeater? Branch Repeater, a branch optimization solution,  provides enhancements to the HDX module maintaining the same high-definition user experience even in the case of deteoriating network conditions (high latency, low bandwidth). Workflows such as file downloads, file views and video downloads work and feel the same across the LAN and the WAN, independent of network conditions.

Oct 22, 2009 4:24 AM Desktop Virtualization Desktop Virtualization  says:

Companies considering desktop virtualization today are doing so to escape from the old tired way of managing applications and desktops in the enterprise. Desktop virtualization allows companies to be  nimble and respond quickly to changes in business environment. It also allows companies to expand its business quickly and cost effectively.


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