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
Type: REG_DWORD
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!)
Virtually Visual 
Thank you, Rachel, Muhammad, and the whole team for the efforts behind this. The improvements are significant as well as appreciated! Here are my own recent findings with XenApp/XenDesktop 7.6 FP3 instances in place:
I started out with going over my ISP from home adding on also our VPN to add more latency, then back to just the plain ISP connection. My average latency with the VPN in place was between 83 and 120 msec with the RTT (the round trip time; for details, see https://www.citrix.com/blogs/2015/03/23/accessing-ica-rtt-metrics-for-citrix-hdx-and-xendesktop-and-xenapp/) at times as high as 200 msec but typically around 100-120 msec. The Thinwire Plus was the only protocol that was established and frame rates were up to perhaps 15 or so. Framehawk had kicked in before under FP2 and an earlier Receiver, but not at all now. That’s interesting in of itself.
I then reconnected without the VPN in between and got lower latencies, between around 63 to 95 msec, so quite a bit better, and RTT more in the 90 – 120 msec range. Framehawk did not kick in at all here, either. Frame rates were as high as 24 for running similar routines with similar operations, so definitely better than before.
The conclusion would be that since latency was not so bad and no packet loss was taking place that Framehawk had no need to turn itself on (it was definitely enabled — I did check that). Hence Thinwire Plus is — I would say — making reasonable decisions as to the connectivity protocol it maintains. In no case would I say I saw any evidence of hesitation for the graphics routines I was using (various AutoDesk products, back-ended by a GRID K2). This is all with XenApp 7.6 FP3 running as a VM under XenServer 6.5 SP1 and the latest Receiver 14.3.100.10 running on an old Dell laptop (Latitude E6510) running Windows 7 over a 15 Mb/1.5 down/up cable modem. Ping time was identical with and without the VPN enabled, at 175 msec.
Best,
-=Tobias
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