Optimising TCP for Citrix HDX/ICA including Netscaler

Marius Sandbu – NGCA (NVIDIA GRID Community Advisor)  aka Clever Viking!

The TCP implementation within Citrix HDX/ICA protocol used by XenDesktop and XenApp and also Citrix Netscaler is pretty Vanilla to the original TCP/IP standards and definition and the out-of-the-box configuration usually does a good job on LAN. However, for WAN scenarios particularly with higher latencies and certain kinds of data (file transfers), Citrix deployments can benefit greatly from some tuning.

Continue reading “Optimising TCP for Citrix HDX/ICA including Netscaler”

NVIDIA GRID: Linux Guest OS support for Linux distributions on Citrix and VMware

I was recently involved in a support inquiry where a user wanted to know if NVIDIA GRID vGPU was available on Linux VDAs with the Linux guest OS, OpenSUSE LEAP (the answer at the time of writing is that it’s NOT!). Finding the answer was a lot harder than I expected as both VMware and Citrix documentation took a bit of hunting around.

Much of the marketing around Linux VDA’s mentions support for “SUSE”, “CentOS” or other genres of Linux, such as this blog. It is important that customers check both their hypervisor and VDI solutions official support matrix as both Citrix and VMware only certify, QA and support specific versions of Linux Guest OSs (usually only enterprise supported versions). Continue reading “NVIDIA GRID: Linux Guest OS support for Linux distributions on Citrix and VMware”

New Cisco Validated Design featuring UCS B200 M4 with NVIDIA GRID M6 vGPU – available now!

It’s great to see a new validated design released by Cisco in recent weeks. Particularly as this features the NVIDIA GRID M6 options for blade servers to enable virtualized GPU-accelerations (vGPU). This reference architecture joins other available for UCS but in particular features a reference blueprint for Citrix XenDesktop/XenApp 7.7 and VMware vSphere 6.0 for 5000 Seats. Key features include

  • Citrix XenDesktop/XenApp 7.7.
  • Built on Cisco UCS (including Cisco B200 M4 Blade Server) and Cisco Nexus 9000 Series
  • with NetApp AFF 8080EX
  • VMware vSphere ESXi 6.0 Update 1 Hypervisor Platform

Cisco have done a great job providing a comprehensive guide and reference for a full VDI/XenApp deployment that includes networking, storage and graphics acceleration considerations.


Cisco-NVIDIA Relationship

There are plenty of case studies, whitepapers and webinar recording covering Cisco long-investment in NVIDIA GRID and vGPU too:

NVIDIA GRID GPUs perfect for keeping up with the Raspberry Pi and the next generation of end points


Citrix have been making a fair bit of noise about their end-client (Receiver) being available and supported in-conjunction with partner ThinLinx on the Raspberry Pi, which with peripherals is proving a sub-$100 thin-client, capable of handling demanding graphics and frame rates (fps) of 30fps or more (YouTube is usually 30fps).

The Raspberry Pi and other low-cost end-points such as the Intel NUC are capable because they support hardware decode of protocols such as H.264 and JPEG used by HDX/ICA, they have SoC (system on a chip) hardware designed to handle graphics really very well. Continue reading “NVIDIA GRID GPUs perfect for keeping up with the Raspberry Pi and the next generation of end points”

When less is more! Avoiding excessive web content!… I hate hi-res stock photography!

Last week I had a twitter user make comment that implied the reason some of our recent thinwire enhancements have happened is because some of the HDX development and product management team are in the UK! Stefan made this comment


After seeing a fellow tweeter struggling to get a decent mobile signal in central London, supposedly one of the world’s most developed cities! Continue reading “When less is more! Avoiding excessive web content!… I hate hi-res stock photography!”

Great real user feedback on thinwire compatibility mode (thinwire plus)!

My colleague, Muhammad, blogged a few weeks ago about a new optimised graphics mode that seems to be delighting users with significant ICA protocol innovations, particularly those users with constrained bandwidth (read the details – here). During its development and various private and public tech previews this feature has been known as Project Snowball/Thinwire Plus/Thinwire+/Enhanced Compatibility mode but in the documentation it is now “Thinwire Compatibility Mode” (read the documentation – here).

I was delighted to read a detailed review by a Dutch consultant (Patrick Kaak) who has been using this at a real customer deployment. In particular it’s a good read because it contains really specific detailed information on the configuration and bandwidth levels achieved per session (<30kbps). Unfortunately (if you aren’t Dutch) it is written in Dutch so I had to pop it through google translate (which did an amazing job).

You can read the original article by Patrick here (if you know Dutch!): http://bitsofthoughts.com/2015/10/20/citrix-xenapp-thinwire-plus/

What I read and was delighted by is the google translated version below:

Since Windows 2012R2, Microsoft make more use of DirectX for the graphic design of the desktop, where they previously used GDI / GDI + API calls. This was evident at the ICA protocol, which was heavily optimized for GDI and triggering a higher bandwidth in Windows 2012R2.

1. without tuning halfway this year we were at one of our customers engaged in a deployment of XenApp 7.6 Windows 2012 R2. Unfortunately, this client had a number of low bandwidth locations. The narrowest lines were 256kbit and there were about seven session running over, which equates to approximately 35 kbit / s per session. We had the h264 (Super Codec) compression already disabled because it caused a lot of high bandwidth and a lot of optimization applied in the policies, but we did not get the line under the 150kbit / s. On average, we came out of around 170 kbit / s. The 35 kbit / s never seemed to be achievable.

After some phone calls with Citrix Project Snowball, we decided to embrace a project that focused on optimizing ThinWire within the ICA protocol and what we call since Feature Pack 3 now ThinWire Plus. This would again reduce the bandwidth to a level which previously Windows 2008R2 was feasible.

After installing the beta on the test servers turned out that we had to force the server to choose the compatibility mode. A moment of choice, because to do so we had to turn off the Super Codec in its entirety for the server for all users that are on there. This forces you to use each session to ThinWire, even where the lines have enough bandwidth and the Super Codec can be used. This is done by implementing the following registry key:

HKLM \ Software \ Citrix \ Graphics
Name: Encoder
Value: 0

It has furthermore been put to Medium in the policy Progressive Compression Level, as was indicated in the guidelines for ThinWire Plus.

snowball active – plus thin wire without optimizations: first results were superb. Immediately after installing ThinWire Plus dropped the average bandwidth already with 50% to 83 kbit / s.

After further tuning of all the components, it was even possible to still continue to go down. Previously had to some extreme measures for people on low bandwidth. The settings were made to further reduce the bandwidth. In the eye is the target frame rate that has been put to 15fps, and the use of 16 bit colors was carried out. Finally, a limitation per session bandwidth imposed maximum of 150 kbps.

gpoMaximum allowed color depth: 16 bits per level. (reduction of 10-15% of bandwidth only for entire server to switch)
Allow Visual Lossless Compression: Disabled
Audio over UDP: Disabled
Client audio redirection: Disabled
Client microphone redirection: Disabled
Desktop Composition Redirection: Disabled (prevents DCR is preferred over Enhanced ThinWire)
Desktop Wallpaper: Disabled (ensures uniform background color)
Extra color compression: Enabled (reduction of bandwidth, increased server CPU)
Additional color space threshold: 8192 kbs (default)
Heavyweight Compression: Enabled
Lossy Compression Level: High
Lossy compression threshold: 2147483647 Kbps (default)
Menu animation: Prohibited (reducing bandwidth by not using menu animations)
Minimum Image Quality: Low (always apply additional compression top sharper image)
Moving image compression: Enabled
Optimization for Windows Media redirection over WAN: Disabled (WMV prevents the WAN towards the client)
Overall Session bandwidth limit: 150 Kbps (for non-GMP, maximum bandwidth per session)
Progressive compression level: medium (required for enhanced thin wire)
Progressive compression threshold: 2147883647 Kbps (default)
Target frame rate: 15 fps
Target minimum frame rate: 10 fps (default)

3. snowball heavy tuned implementation of this policy came in the test situation, the average at 16 kbit / s. A value that we absolutely did not think we could get to in the beginning. In the user tests it was revealed that it still worked well on the environment, despite all the limitations that we had set in the policy.

After all changes were made in the production environment, we see that an average session now uses around 30 kbit / s. Slightly more than in the test environment, but certainly not values ​​that we complained about. Users can operate well and be happy.

Incidentally we discovered when testing behind it at a pass-through application (where users first connect to a published desktop and then launch a published application on another server), the ThinWire Plus configuration on both servers must be running. If we did not see we increase the bandwidth usage to the client again significantly.

(all my colleagues, thank you for providing the performance measurements!)

Testing Graphics Protocols – Try Chinese Text – With the aid of some ropey pseudo-maths!

In HDX we use a variety of compression and text recognition algorithms to ensure bandwidth is used efficiently but also that screen elements like text or CAD wireframe/hidden-line are clear and sharp. When testing graphics protocols, we often try to ensure that we don’t just look at the average or mass usage case (in the case of a product like XenDesktop that’s often test workloads like Microsoft Office on windows laptops as the end points). We also look at those use cases which are most challenging e.g. using very old and low-powered Linux thin-clients as end-points because if we can get performance and quality in such scenarios the user experience is better for all our users.

In the case of text quality, we often look at non-English fonts Continue reading “Testing Graphics Protocols – Try Chinese Text – With the aid of some ropey pseudo-maths!”

HDX: Enhanced Support for 3D and CAD Cursors with Citrix XenDesktop/XenApp 7.6 FP3

Citrix XenDesktop/XenApp 7.6 FP3 has introduced enhanced architecture to support both 24-bit and 32-bit advanced cursors. Historically remoting protocols have supported simpler cursors but with an increase in the use of complex and larger cursors for complex CAD and 3D applications, Citrix has introduced a new architecture to support such cursors on-going.

Continue reading “HDX: Enhanced Support for 3D and CAD Cursors with Citrix XenDesktop/XenApp 7.6 FP3”

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