User experience is one of the key reasons many IT organizations continue to expand their XenApp and XenDesktop implementation. The new HDX Thinwire makes it even more compelling to expand and upgrade to XenApp or XenDesktop 7.6 Feature Pack 3 — with better performance and (wait for it) higher returns on investment.

So what does this mean for you? How do you deploy the good stuff? How do you decide the right option for your environment?

Before we answer your questions in this post, let us step back and cover some basics.

What is HDX Thinwire?

Thinwire has been a core engine of the ICA virtual display channels, in one form or other, for over two decades now! Under the hood, different methods are employed to address the wide range of conditions between the centralized resources and the user. It is continually evolving to keep up with advances in hardware, operating systems, peripherals, networks and other building blocks of the ecosystem. Feature Pack 3 (FP3) includes a new invention to deliver great user experience with significantly smaller CPU and bandwidth footprint. During its development, this innovation was variously known as Project Snowball, Thinwire Plus, Enhanced Thinwire, Enhanced Compatibility Mode, Next-Gen Thinwire, and so on.

All these terms refer to the same thing: a new method within the good old HDX Thinwire protocol.

What alternative methods are available in HDX Thinwire?

HDX provides a superior graphics and video experience for most users by default, with no configuration required. Citrix policy settings that provide the best out-of-the-box experience for the majority of use cases are enabled by default. In the current release, this is a Thinwire method that uses “Video Codec for compression” when the client device is capable, and a fallback, if not. This method, too, has different names in Citrix literature, such as the SuperCodec, DeepCompression, Thinwire Advanced, and H.264 mode, among others.

‘Video codec for compression’ is a versatile method and provides very high quality user experience, especially for visually rich display elements and multimedia. It uses H.264 compression, which is the same technology used to stream HD videos efficiently over the Internet. The trade-off is that it consumes more resources to encode and decode, which requires a relatively high-power processor on the client and impacts user density on the server.

The fallback I mentioned above is the new Thinwire method introduced in FP3. The new Thinwire method uses a combination of low-cost algorithms that are more widely compatible with any operating systems, any end-points, and any type of network. Whether you have thin-clients running Citrix Receiver 11.x or 12.x, network bandwidth as low as 128Kbps, or users in distant locations, Thinwire delivers a delightful user experience with a very efficient CPU and bandwidth footprint. This is no small feat, as we’ll see in a moment.

It is turned on automatically if the default method fails to kick in; for instance, when the end point has an older Receiver version or a low power CPU. In other cases, you may want to turn it on by policy even when clients are capable of supporting video codec compression; for instance, to save network bandwidth or increase user density per server.

HDX Policy Templates
Thinwire Graphics Delivery Options in HDX Policy Templates

Today we are only talking about this specific new HDX graphics delivery option. There are other HDX strategies that intelligently maintain the best user experience when conditions change or become sub-optimal. That’s a discussion for another day.

How do I select the right HDX graphics strategy?

The right strategy depends on what your goals are. Think of user experience and user density per server as two ends of a sliding scale. Administrators use their organization priorities and users’ expectations to find equilibrium on this scale. To help administrators manage this natural trade-off with minimum effort, we introduced completely revamped HDX Policy Templates in FP3. Instead of error-prone scrambling to tune individual settings, these templates in Citrix Studio deploy the optimum set of settings for the selected use case.

Disclaimer: This is just an overview. See product documentation (here) for detailed instructions on the use of policy templates and the new Thinwire mode.

My colleague Marcel has published a white paper describing HDX policy templates in detail. I highly recommend these resources to understand the concept completely. 

Let’s discuss a few of the strategies here:

  • If your goal is to achieve the best user density per server, fine tune visual elements to a point where server CPU needs to work less hard and human-senses continues to enjoy a good user experience. Use the High Server Scalability (HSS) template to force on the new Thinwire mode, and prevent the use of video codec. This template also changes other settings such as visual quality, frame rate, color depth, and so on. Preventing video compression still allows Youtube videos to be played or 2D/3D graphics to be delivered, albeit with reduced optimizations for such workloads.
  • Where multimedia and visually rich workloads are a priority, the video codec compression is what you want. If the business case demands the highest quality visual display, the default policy should take care of it. To make sure video codec is always used, use the Very High Definition User Experience (vHDX) template. The policy based on this template will implement other changes to printing, audio, menu animations, and so on to provide first class experience. The solution is still very scalable, but not as high as the HSS alternative.
  • The third major use case would be branch and remote users with significant latency and access to lower bandwidth pipes. Most of the settings in such conditions are similar to High Server Scalability. The Optimized for WAN (WAN) template enables more frugal behavior for printing, audio, file sharing, and other activities which tend to consume bandwidth when available. It also turns off video codec to enable the bandwidth-efficient Thinwire method.

What are the additional policies labeled ‘Legacy OS’?

Graphics delivery of virtual desktop or app consists of two parts: graphics provider and graphics delivery. HDX technologies work their magic on graphics delivery portion. The trick is simple: never send the actual screen display; instead, encode the drawing operation that produces the image and compress it before sending. The graphics provider produces the actual screen display. In the case of Windows operating systems that is Microsoft. Key changes to the graphics stack made by Microsoft, starting in Windows 8 and Windows Server 2012, required changes to the graphics delivery “magic”. The new Thinwire methods, both with and without video codec for compression, are designed to handle the graphics provider on these so-called modern OS (Windows 8, 8.1, 10, and Server 2012/R2).

HDX Thinwire Graphics Optimized for Legacy Windows OS
HDX Thinwire Graphics Optimized for Legacy Windows OS

To maintain backward compatibility with Legacy OS such as Windows 7 and Windows Server 2008/R2, Citrix provides additional policy templates. While the new Thinwire supports all Windows versions, use one of the templates labeled ‘Legacy OS’ to get the best performance when using resources on those operating systems. The performance will be much better.

Finally, why does everyone keep calling the new Thinwire “a big leap in innovation”?

Good question! The server scalability benefits are but a small fraction of the good news. With its small CPU footprint, new Thinwire in FP3 is compatible with older thin clients, low-powered end-points, and clients running legacy Citrix Receiver versions (Linux 11/12, versions prior to Windows 3.4) that cannot be upgraded for any reason. With its small bandwidth footprint, branch offices can access the latest apps without costly bandwidth upgrades.

Run Windows 10 Desktop on Thin Clients from 2009? No Problem!
Run Windows 10 on Thin Clients from 2009? No Problem!

In other words, the power of Windows 10 or fancy new USB peripherals in the cloud are available to existing users with zero client-side investments! This is a big deal for many of our customers who purchased thin clients over 5 years ago and don’t have the budget or administrative staff to immediately upgrade user devices. Until the new Thinwire came along, customers were forced to upgrade thin-clients or firmware to take advantage of new server features. With this unique compatibility from new Thinwire, their old hardware gets a new lease of life!

So that’s our big leap of innovation: the latest and greatest user experience at a return on investment (ROI) unmatched by any other vendor or technology. Feature Pack 3 provides an excellent migration path for XenApp 4.x, 5.x or 6.x customers to move to XenApp 7.x or XenDesktop 7.x.

Ready to take the leap yourself?

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