Understanding Thin Clients for Citrix – Just Got A Whole Lot Easier!

Update (5th/Jan/2016): Sagnik who ran this project has now published a comprehensive overview of the official information available from Citrix, including some tips on using the new database and enhanced search functionality – essential reading – click here.

I’ve recently left Citrix and was pleased to see some of the projects that I worked on as Linux Receiver Product Manager come to fruition which have been a long time in the making. The Linux Receiver is quite different to many of the Citrix Receivers in that:

• It’s mostly consumed via third party OS or thin-client OEM vendors
• The hardware it is installed on varies hugely in capabilities and is often lower powered than your average windows PC
• Thin-client costs are often a significant % of a virtualisation project, up front and hardware refresh cycles can be long so choosing the wrong thin-client is expensive
• The OEMs/vendors that integrate the Receiver need developer support and the level of integration varies widely between vendors, so thin-clients with similar hardware can actually have vastly differing performance
• The capabilities of the version of operating system affects whether the Receiver can fully leverage the hardware
• The graphics mode in use determines the CPU/GPU needs and low-powered devices often performed poorly with CPU intensive modes such as H.264 based codecs
• Customers often experienced poor performance as they simply had mis-configured graphics policies

When I first started working with the Linux Receiver, I faced a barrage of inquiries and customer issues. OEMs and partners also found it hard to explain to customers what to expect of a thin-client. There was an existing Citrix Ready program for thin-client certification, the technical certification was rigourous but it was very hard to interpret and the information wasn’t easy to consume. A joint project was set up with the Receiver product managers, Citrix Ready, Linux Receiver Engineering and OEM alliances to try and address this led by Sagnik Datta. In the interim I ended up blogging about the complexity and technicalities of thin-client certification, you can read that blog – here. I ended up having to link to certification documentation and a lot of information was simply missing.

Well Now That Has All Changed!

Last week, Citrix Ready launched a new website and documentation about thin-clients:

• https://citrixready.citrix.com/info/thin-clients.html

This page links to a document overviewing the meaning of the three certification levels for thin-clients: “HDX Ready”, “HDX Premium” and “HDX 3D Pro”. This super document (https://citrixready.citrix.com/content/dam/ready/assets/thin-clients/thin-clients-features.pdf) allows a user to look at what a thin-client has as a minimum, it also gives a good overview of the other levels, allowing a customer to think about whether actually they will need multi-monitor or smart-card support in the future. The specific tests and frame rates a client needs to achieve for a standardised set of tests are now transparent to customers. These tests were always undertaken but the information was hidden away in OEM documentation.

During the process, the certification tests were all re-evaluated and many areas greatly enhanced such as the smart-card tests standardised on PIV compliant devices. This was a particularly complex and slow project due to the need to consult with 40+ OEM vendors. When you are changing certification standards you need to allow vendors to integrate the new within their existing development and test schedules. We also wanted to make sure that this time we got it right, so there was lots of review iterations, training and looking at how other vendors handled this complex area.

You’ll also notice recently certified thin-clients carry more information on standardised technical specifications. E.g. the new HP T730, https://citrixready.citrix.com/hewlett-packard-company/hp-t730.html, where performance affecting components of what was certified are recorded e.g. firmware version, and operating system. This means a customer can verify what minimal frame rate to expect with certain workloads with a specific firmware version to eliminate other issues.

Other Changes:

Other changes in HDX have been designed to help users choose more appropriate thin-clients and get the best performance out of them, it’s worth reading about these:

• Templates: Ways to configure graphics policies to optimal configurations – Hidden away in the product documentation for XenDesktop/XenApp 7.6 FP3, you will find documentation on new built-in templates for use cases (the documentation is here – http://docs.citrix.com/en-us/xenapp-and-xendesktop/7-6/xad-policies-article/xad-policies-templates.html).There is also very good whitepaper written by Marcel Calef that goes into the details of why policies are set in these templates, which in my opinion is a must read for any Citrix System Administrator, available here: http://support.citrix.com/article/CTX202330. Along with XenDesktop/XenApp 7.6 FP3, we’ve released a CTX article linked to from the Studio Console where we are adding additional templates optimised for Cloudbridge, HTML5 and other uses – it’s really worth checking out: http://support.citrix.com/article/CTX202000
• Thinwire Compatibility Mode – a low CPU and low bandwidth footprint graphics mode, suitable for legacy and/or low-powered thin-clients, introduced with XenDesktop/XenApp 7.6 FP3: https://www.citrix.com/blogs/2015/10/09/a-big-leap-in-ica-protocol-innovation-for-citrix/
• Support for new ultra low-cost “thin-clients” as a result of working with vendors such as ThinLinx such as the Raspberry Pi2 (http://www.theregister.co.uk/2015/12/14/vdi_comes_to_the_raspberry_pi/) and the Intel NUC (https://virtuallyvisual.wordpress.com/2015/08/02/did-i-really-see-a-165-thin-client-doing-55fps-with-borderlands-2-with-hdx-3d-pro-citrix-xendesktop/)