Citrix XenApp & Microsoft (online) Lync… Things to be aware of. My findings!

Just recently I was in the process of researching to use Lync online (Office 365) in a XenApp HSD environment for one of our customers. To be honest I expected this to be a relatively straightforward process, install the software, configure, perhaps adjust my sizing numbers somewhat, test and take it from there. But what I found was that using Lync online combined with XenApp has its limitations. Of course some of these limitations can be dealt with, others however, we just have to except or take another route completely.

Preferably we don’t want to make any concessions when it comes to sizing, performance and ultimately, the end user experience. It all starts with the way we ‘deliver’ the Lync client. Because even though we will be using Lync online, some software still needs to be installed. Whether we go with generic HDX or optimized HDX, certain server and/or client components will be needed. Remember that I’m focusing on a hosted shared desktop solution here, and even more specific, combined with Lync online, and not an on-premises Lync server infrastructure, although I do mention some of the other options as well.

Lync client delivery

As mentioned, there are a few ways in which we can ‘deliver’ the Lync client, two to be precise: generic and optimized. With generic you basically have one option, you install the full Lync client onto the XenApp server and that’s that. This can be the Lync 2010 or the 2013 client. Using this method all-processing will take place on the server side, which in my case is not the preferred way to go.

Note that Microsoft does NOT officially support the Lync 2010 on Microsoft Windows Server 2012 R2. It is however, fully tested and approved by Citrix. Because of this it is expected that the 2013 Lync client won’t be supported on Server 2012 R2 as well. Decision time!

The optimised way(s)

When using the (preferred) optimised HDX method, we have three options. Let’s start at the top, the Lync VDI plugin. The Lync 2013 client, or 2010 for that matter, is licensed as part of Microsoft Office Professional Plus 2013, which is available to TechNet subscribers. It is installed on the end users (physical) computing device and (assumably) it only supports Windows 7 SP1 clients at this time. On the server you still need to install the full Lync client. This comes from the supporting CTX document: The Lync VDI Plug-in is designed as a plug-in to Citrix Receiver for Windows. Use of the Lync 2013 VDI Plug-in combined with Citrix Receiver 4.x. Once set up, these two components will interact and exchange data making sure that the real processing of Lync data will be done on the end users computing device with the Lync VDI plugin installed, saving resources on the VM.

Pay attention now!

This is where it gets interesting. If you go this page, you’ll see that Citrix has a whole list of supported setups and configurations, including XenApp 6.x and XenApp 7.x combined with published desktops, a.k.a. hosted shared desktops. Which I find kind of strange since it is clearly named the Lync VDI plugin, that’s pretty specific don’t you agree? Also, the virtual desktop OS listed on that page claims that only VM’s with Windows 7 SP1 are supported by Microsoft, or as they like to cal it, formally Lync Qualified by Microsoft. While at the beginning it states that Citrix also supports XenDesktop 7.x deployments of Windows 7 and Windows 8.1 Desktop OS machines. Now I’m not really sure what this means, but I guess that Citrix will support both while MS will only officially support Windows 7, I think. But maybe I’m interpreting it wrong.

I’m not done

But wait, there’s more. Let’s have a look what Microsoft has to say about this. First go here. The first thing you will notice without having to read to far into the document is that the VM’s need run Windows 8, 7 or Windows Server 2008 R2 (remember, you can also do server VDI on a one to one basis). This contradicts the earlier statement made by Citrix, it being only Windows 7 SP1. Although they do mention XenDesktop 7.x combined with Windows 7 and 8.1, however, no Windows 8 though.

On the same page, have a look at the supported (physical) endpoint OS’s, or the ‘local computer’ as Microsoft likes to call it. Windows 7 SP1 and Windows Embedded 7 SP1 standard edition are both on there as well, but so is Windows 8, and that’s nowhere to be found in the CTX doc. strange right? But perhaps I’m being a bit to specific here.

Now go here, believe me, you want to check this one out as well. Now does it, or does it not state that Remote Desktop Sessions in the form of Remote Desktop Services or Citrix XenApp are NOT supported? What is a man to do? Citrix says, it works and we support it, Microsoft just says, we do not support it, again decision time. Never mind my remark on the Lync client not being supported in Windows Server 2012 R2, earlier. Again, my interpretation, but I don’t think I’m far off.

Doesn’t bother me though

Anyway, in my (customer) case this all didn’t matter since the Lync VDI plugin does not support Lync online, only on-premises Lync infrastructures, so on to the next. Of course this doesn’t mean that technically it won’t work, because it does, it’s just a matter of getting the support that you need when you need it. And we all know that can be tricky sometimes.

On to the next. Nr. 2

Number two on the list of optimized HDX delivery methods is Local App Access. I think this option / technology pretty much speaks for itself. It was introduced with XenDesktop 7.0 and is also known as Reverse Seamless, something that RES has been doing for many years now. Have a look at this page for some more information on some of the pros and cons that come with it. Funny thing is, if you click the link on the ‘feature limitations of the VDI plugin’ from the above page, you’ll end up on the Microsoft website stating that the VDI plugin is not supported on XenApp etc… But don’t forget to check some of the other mentioned limitations as well, it’s important when needing to decide which route to take. Oh, and yes, it is a XA / XD Platinum feature, which my customer does not have, so case closed on this one as well.

And finally…

Number three is the HDX RealTime Optimization Pack for Lync. We have a winner! It’s compatible with XenApp as well as XenDesktop 7.6 and not to long from now we can expect a new release, version 1.7 (scroll down :) currently it’s 1.6. XA and XD 6.5 and 5.6 are also supported by the way. This one is a bit special, not only does it support the above-mentioned platforms; it will work on MAC, Linux as well as Windows endpoints. Next to that it is compatible with Lync server 2010, 2013 and Lync online. Now we’re getting somewhere. It even supports Active Directory Federation Services (ADFS) with RealTime Connector 1.6 and RealTime Media Engine 1.6 or 1.5. Using AD FS removes the requirement to maintain Lync user accounts in the Microsoft cloud. And that’s great.

There is a drawback as well; it will only support the 2010 Lync client, at least for now. This will be fixed in version 1.7, read more here. However, it does support Lync 2013 server back-end configurations. Here you’ll find a Citrix TV video (just released) about Lync on XenApp and XenDesktop, and more specific, the HDX RealTime Optimisation Pack version 1.7

UPDATE: 31-03-2015 – the HDX RealTime Optimization Pack version 1.7 has just been released, read the latest Citrix blog post on it here. The Lync 2013 client is now fully supported. The rest of the article has been updated to reflect the capabilities of version 1.7. As far as the 1.6 mention above, this all applies to version 1.7 as well.

You’ll find its complete technical overview here. Here’s a short excerpt:

HDX RealTime Optimisation Pack consists of both client and server components:

1. The client component, called HDX RealTime Media Engine, integrates with Receiver on the endpoint device and performs all signaling and media processing directly on the user device itself, offloading the server for maximum scalability, minimizing network bandwidth consumption and ensuring optimal audio-video quality.
2. The server-side (and virtual desktop) component, HDX RealTime Connector for Microsoft Lync, is a connector to the Microsoft Lync client that drives the RealTime Media Engine on the endpoint. RealTime Connector runs in the virtual server environment alongside Microsoft Lync and communicates signaling information over a Citrix ICA virtual channel to the RealTime Media Engine running on the user device.

The basics

1. The user starts, or requests, a Lync online session from the XenApp server. I assume that our user already has an active  hosted shared dektop session running.
2. Lync online (Office 365) will receive the request to initiate a new Lync session but the user needs to be authenticated first. Step two and three basically go hand in hand.
3. Since ADFS has been configured the request will be send back to the XenApp server / session from where it will be forwarded to the Office 365 ADFS server.
4. From there the authentication request will again be routed through the XenApp server / session on to the on-premisses ADFS server.
5. Next the user / session will be authenticated in, or by, the on-premisses Active Directory.
6. Once authenticated, the request will be forwarded to the XenApp server / session.
7. And finally it will end up back in the Lync online cloud where the authenticated user will be allowed to start a new session and Lync will be initiated within the XenApp / user session.

There are limitations

Same rules apply here as well, two separate components need to be installed, server and (physical) client. All (real) processing will take place on the client device, offloading the XenApp server. If you have a look at the feature (technical) overview on the E-docs webpage, see the link above, you’ll notice that there isn’t much it can’t do, or so it seems. But don’t forget to scroll down completely. Although version 1.7 has again brought a whole bunch of improvements and additional features to the table, there are some very specific limitation known to version 1.7 you need to be aware of. I’ll list some of them (not all) here as well:

• Lync basic is not supported by the RealTime Connector. Workaround: Use the full version of Lync.
• Response groups is not supported.
• Delegation is not supported.
• There is no RealTime Connector for Microsoft Lync 2010 in this release. Lync 2010 users must continue to use the 1.6 version of the RealTime Connector with a compatible RealTime Media Engine.
• Voicemail access and playback is not supported. Use Microsoft Outlook to view, access, and playback voicemail messages.
  Recording is not supported.
• The Auto-discovery method of locating Lync servers is not implemented. Configuration must still use the DNS/SRV method for Lync server discovery.
• Gallery view is not supported in multiparty calls.
• Active speaker view is used in Lync multiparty calls using Optimization Pack.
• There are no Call and Video Call buttons in the Lync Contact Card.
• On Linux terminals, the RealTime Media Engine installer disables multimedia redirection in Linux Receiver. This avoids Optimization Pack and Linux/Unix Receiver getting into a conflict when accessing video devices. However, this means that other Unified Communications applications cannot work with Generic USB redirection when accessed on a Linux terminal that has RealTime Media Engine installed.
• The date and time strings on USB telephone devices with display capabilities are not properly localised.

Fallback

As you may have noticed, the Lync client will still be installed on the XenApp server as well, see bullet number two. So there are actually two components installed on the server side. I’m not a 100% sure if this is a prerequisite, but if I were you I’d just leave it on there. If for some reason the endpoint device isn’t able to process the Lync data it will fallback to server processing and it will need and use the Lync client for that. Lync 2013 as of version 1.7 that is, as stated earlier.

Customer specific

My client will use a variety of devices, fat clients in the form of laptops and desktop, but thin clients will be rolled out as well. Using the HDX RealTime Optimization Pack has its drawbacks with regards to some specific features not being available, so as soon as I have the (exact) Lync requirements from my customer’s perspective I can make some decisions. Also, the type of TC is still to be decided on as well. Perhaps in the end TC’s won’t be optional at all, who knows. Or maybe we’ll just do chat. All in all I think this post showed you that no matter which form of Lync you would like to use, some planning and research is in order, but then again, I guess it always is.

Let me end by saying that this post isn’t meant to be negative with regards Citrix / Lync implementations, not at all. I just think it’s important to list all facts before making an informed decision on which route to take. If you feel that I left anything out, or I interpret / explained something completely wrong, please let me know and I’ll correct (if I agree as well). I’m only human :)

Bas van Kaam

Field CTO EMEA by day, author by night @ Nerdio

Father of three, EMEA Field CTO @ Nerdio, Author of the book Van de Basis tot aan Meester in de Cloud, Co-author of the book Project Byte-Sized and Yuthor of the book: Inside Citrix – The FlexCast Management Architecture, over 500 blog posts and multiple (ultimate) cheat sheets/e-books. Public speaker, sport enthusiast­­­­­­­­: above-average runner, 3 x burpee-mile finisher and a former semiprofessional snooker player. IT community participant and initiator of the AVD User group Community world wide.