What Licenses Do I Need….

Earlier this week, I had a long discussion with a client (you know who you are) about what licenses they would need for a deployment of “zero client” devices. We’ve written a lot about Microsoft and Citrix licensing, about XenDesktop and XenApp, about the Citrix trade-up, etc., but it occurred to me that it might be beneficial to pull all the licensing information together into one post instead of expecting you, gentle reader, to have to sort through multiple posts to pull it all together.

So, let’s discuss Citrix licensing first, then move on to the Microsoft licensing.

First of all, if all you want to do is to deploy VDI (Virtual Desktop Infrastructure), and you have a limited number of users, then you should probably purchase VDI-in-a-Box.

If you decide that VDI-in-a-Box is not the right fit foryou, the next question you need to answer is whether to use XenApp licenses or XenDesktop licenses. Beginning with the introduction of XenDesktop v4.0, Citrix concluded, reasonably enough, that an organization that was deploying VDI probably wouldn’t get much leverage from a concurrent-use licensing model, because their concurrency ratio (by which I mean the ratio of total users to concurrent users) would be pretty close to 1:1. So XenDesktop v4.0 was introduced with a per-named-user or per-device license model. These licenses were roughly half the cost of the comparable XenApp concurrent-use license: XenApp Enterprise Edition, for example, carries an MSRP of $450 per concurrent user. XenDesktop Enterprise Edition carries an MSRP of $225 per user/device.

At the same time, Citrix made the decision to include XenApp rights in the XenDesktop license. So if you buy XenApp, you get only XenApp. But if you buy XenDesktop, you get both XenDesktop and XenApp - so you can use XenApp to stream applications to your virtual desktops, or have your virtual desktops function as client devices that run published applications that execute on the XenApp servers, or simply deploy a mixture of XenDesktop and XenApp to your user community depending on what delivery method is best for a particular use case. This is what Citrix refers to as the “FlexCast” delivery model.

This created the interesting situation where, because of the difference in license cost, if your concurrency ratio was less than 2:1, you were better off financially to purchase XenDesktop licenses even if all you really wanted to run was XenApp. And, since delivering what Citrix calls “hosted shared” desktops from XenApp servers makes more efficient use of the underlying hardware and storage infrastructure, the bias should probably be toward XenApp unless there is a clear use case for why users need to connect to individual desktop OS instances rather than a shared XenApp desktop (and it isn’t just appearance, because with XenApp v6.5 on Windows Server 2008 R2 we can deliver a XenApp desktop that looks and feels like a Windows 7 desktop). But, for the sake of this discussion, let’s move on down the XenDesktop trail.

Citrix has re-introduced a concurrent-use license option for XenDesktop, which is a better choice for organizations who want to deploy both XenDesktop and XenApp, but have a concurrency ratio greater than 2:1, but so far, I haven’t seen very many use cases where that license model made sense.

If you already have XenApp licenses, and want the ability to deliver VDI as well, you can take advantage of the Citrix trade-up program to transform your XenApp licenses into XenDesktop licenses. And if you trade up all of your XenApp licenses, you can get two XenDesktop user/device licenses for each XenApp license. So 250 XenApp licenses would become 500 XenDesktop user/device licenses. If you want more information on how the trade-up program works, and what your trade-up options are, check out the handy Citrix Trade-Up Calculator.

As of the release of XenDesktop v5.0 Feature Release 1, the license service got pretty smart in terms of how it managed those user/device licenses. This is good news for, say, a hospital, which may have devices that are used by multiple users and other users who use multiple devices. The license server can intelligently and dynamically reassign licenses between users and devices to make the most efficient use of the available licenses. For example, consider the following scenario for a brand-new environment where no licenses have yet been assigned:

  • User 1 logs on from client Device 1. The license server will, by default, check out a license to User 1.
  • User 1 logs off, and User 2 logs on from the same client device. The license server, now sensing that two different users have logged on from the same device, will take the license that was assigned to User 1, and reassign it to Device 1. Any subsequent users who log in from Device 1 will not cause any action by the license server, because Device 1 is already licensed.
  • If User 1 logs on again from a different client device, the license server will again check out a license to User 1 (so, at this point, two licenses are checked out: one to Device 1 and one to User 1). Since User 1 has logged on from two different devices, the license will remain assigned to User 1 unless/until manually released by an administrator (e.g., in the case of the employee leaving the organization), or unless User 1 doesn’t log on for a period of 90 days, in which case it will be automatically released due to inactivity.
  • Likewise, since two different users have logged on from Device 1, that license will remain assigned to that device unless manually released or automatically released due to 90 days of inactivity.

So…how do you know how many licenses you really need? There is actually a formula that will tell you that. You need to know how many total users you have (let’s call that number “A”), how many shared devices you have (let’s call that “B”), and how many of your users will use only shared devices (let’s call that “C”). The formula is A - C + B. So, if you have 1,000 total users, 300 shared devices, and 600 of your users will use only shared devices, you need 1,000 - 600 + 300 = 700 total licenses.

For more information on exactly how this works, see the Citrix Community Blog post by Christophe Catesson, which in turn links to a recorded session from Synergy 2011 that was a deep dive discussion of XenDesktop licensing.

Now for the Microsoft licensing component.

If you have users who will be executing applications on a XenApp server, you will need a Remote Desktop Services (RDS) CAL for that user, or for the client device that user is using. It is very difficult to manage a mixture of user CALs and device CALs in a Remote Desktop Services environment, so, in most cases, you’re going to be better off purchasing user CALs.

If you have users who will be attaching to a virtual desktop instance, the licensing requirements are different, depending on the client device. If the client device is a Windows PC whose Operation System is covered by Software Assurance, you do not have to purchase any additional Microsoft license to use that PC to connect to a virtual desktop. If the client device is not a Windows PC, or that copy of Windows is not covered by Software Assurance, you need a Virtual Desktop Access (VDA) license for that client device. VDA licenses are only available under the Open Value Subscription license model at present, meaning that you will continue to pay for them every year. Forever.

But wait! That’s not all! As Gabe Knuth outlines in a recent article on Techtarget.com, there is a very strange loophole in the VDA license terms. If you have a VDA license for your primary device (or if it’s covered by Software Assurance), you have what Microsoft calls “Extended Roaming Rights,” which allow you to also use your home computer to access your virtual desktop, or use your iPad when you’re at home or traveling. But, technically, it does not entitle you to bring your iPad into the office and use it there! To solve that (using the term “solve” loosely), Microsoft recently announced something called a “Companion Device License” (CDL) which allows you to use up to four other devices (in addition to the primary licensed device) to access your virtual desktop. No word yet on what the CDL will cost.

So let’s see if we can summarize what our client would need for a deployment of “zero client” devices (like, for example, the Wyse Xenith thin client).

  • You’re going to need some kind of Citrix license, either VDI-in-a-Box, XenDesktop, or XenApp.
  • Since the thin client is not a Windows PC, and therefore cannot be covered by Software Assurance, you would need to purchase a Microsoft VDA license for it.
  • If the thin client will be used only to attach to a virtual PC desktop and execute applications within that desktop OS environment, no additional Microsoft license is needed. However, if the thin client will also be used to attach to applications that are executing on a XenApp server - either directly or indirectly by having the Citrix client baked into the virtual PC desktop - you will also need a Microsoft RDS CAL.
  • You do not need an RDS CAL if you are only using XenApp to stream packaged applications to a virtual (or physical, for that matter) desktop for execution there. Since you are not actually utilizing Remote Desktop Services by executing code remotely on a Remote Desktop Server, no RDS CAL is required.
  • If you want to institute a BYOD program, where users can bring whatever client device they wish into the office and use it to access your VDI, you’ll probably need some of the new Microsoft CDL licenses.

If I’ve overlooked anything, feel free to submit questions via comments on this post, and we’ll try to get them answered. Let the discussion begin!

About Sid Herron

Sid Herron has been involved with Citrix technology since the days of WinFrame (the NT v3.51 product). He has held a number of sales and marketing management positions within the company, and currently serves as VirtualQube's Director of Sales and Marketing.

57 Thoughts on “What Licenses Do I Need….

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  2. Pingback: The Elusive Windows “Companion Subscription License” - a Solution In Search of a Problem | VirtualQube Blog

  3. Thank you Sid for the article. Its really helpful to understand the complex/confusing licensing models.
    We are a government agency. I am planning to implement a cost effective VDI solution. To start with I bought a VDI in a box 25 user concurrent user licence. Creating master VM with Windows 8.1 pro and Office 2013 std (only word,excel and Power point).

    We already have required VDA license, Office licenses, Windows CALS and Windows 8 pro licenses. Since I am bundling the applications with VM, do I still need RDS CALS licences?

    • Thanks for participating, NK. No, you do not need RDS CALs if you are deploying virtual instances of Win7 or Win8. You would only need RDS CALs if you are executing applications on a 2008 or 2012 Server via Remote Desktop Services.

  4. Johnb484 on May 11, 2014 at 11:03 pm said:

    I think this is one of the most significant information for me. And i’m glad reading your article. But should remark on some general things, The web site style is wonderful, the articles is really excellent D. Good job, cheers

  5. Johnd950 on May 11, 2014 at 11:02 pm said:

    Thanks for the article, is there any way I can receive an email whenever you publish a new update?

  6. VDIrob on April 7, 2014 at 11:29 am said:

    The only bad thing about not having RDS cals if you’re only streaming appls, is you can’t RDP to those servers. It will complain about he lack of RDS cals. You have to walk to the server console/kvm.

    • Thanks for that post. Let me make sure I’ve got this right: normally you would have the right to log onto a Windows server remotely as an administrator without having to have an RDS CAL. But what I think you’re saying is that, since you can’t install XenApp unless you enable the Remote Desktop role on the server, you then find yourself in a place where the server now complains about the lack of RDS CALs even though you’re logging on as an administrator. That is a bit of a PITA. But the good news is that you should be able to get away with purchasing just a few RDS user CALs for the folks that will need administrative access, as opposed to having to buy RDS CALs for everyone.

      • VDIrob on May 7, 2014 at 10:48 am said:

        Thanks Sid, good solution. Are the CALs just installed on the server? so for example if you install 3 of them, up to 3 admins can get in remotely? Or do you need to configure your CALs with your personal VM hostname? And if so, if your hostname changes, can you modify it in the CAL?

        • Somewhere in your environment, you need a server that’s running the Microsoft RDS license service. It doesn’t necessarily have to be a Domain Controller, but my understanding is that if it is a DC, your Remote Desktop Server(s) will automatically be able to find it. You would put the RDS CAL serial numbers into your license server and activate them. If you buy User CALs, the license server will associate each CAL with a username, and it will cover that user regardless of how many different Remote Desktop Servers that user may access.

  7. Maxwell on April 5, 2014 at 9:28 am said:

    Hello Sid,
    Basically, for a XA enviroment we always need a Citrix license + RDS + RDSCAL, is this right? And for a XD enviroment we need only Citrix and RDS licenses once my source is a windows pc?

    This post is from 2012, this explanation is valid for 2014? What are the differences that we can find now?


    • Max,
      Thanks for your reply. The license model hasn’t changed in the last couple of years, but I think I see some confusion that we should clear up. Yes, for a XenApp environment, you always need a Citrix license, an RDS CAL (either user or device), and, of course, a Windows Server with Remote Desktop Services enabled. That Citrix license can be a XenApp v7.5 license (yes, Citrix re-introduced XenApp as a stand-alone product after confusing the heck out of everyone with the v7.0 release, in which it was called “XenDesktop App Edition”), or it can be a XenDesktop Enterprise or Platinum license. XenDesktop environments in which you are not running applications on a Remote Desktop server do not require an RDS CAL. But in order to access a virtual instance of Windows 7 or Windows 8, you must comply with the license guidelines above: either your client device is a PC that’s covered by Software Assurance, or you must purchase a VDA license for that client device.

  8. Great Article! One question…

    I’m in an environment where we want to virtually host a few hundred instances of Windows 7 Enterprise, and access them from 103 Linux Desktops via VNC.

    We’re an all-Linux shop today, so I’m not in any sort of Volume Licensing agreement currently.

    Am I understanding you correctly in that I just have to buy 103 VDA Licenses (and renew them yearly), and then I have the right to run unlimited copies of Windows 7 Enterprise?

    • It’s not unlimited: The Microsoft Product Use Rights document (which you can download from their Web site) states that, from the client device to which the VDA license is assigned, “you may remotely access up to four instances of the software running in virtual OSEs on servers in your datacenter.” (“OSE” = “Operating System Environment”)

  9. I have a very basic question that I cannot find an answer to anywhere:

    I am thinking of deploying vdi in a box for a small business that will have 5 Windows 7 or 8 vms. What type of Microsoft licensing do I need so that I get both the operating system install as well as the activation keys for the 5 instances?

    This is a small geologist shop that will have different contractors log in remotely using their non-SA devices and run proprietary software on the vms.

    All the reading I have done on microsoft volume licensing has confused the heck out of me. I asked a reseller for a quote on 5 OS licenses with SA and he sent me skus for Windows 8 pro upgrade with SA. What I tried to explain to him is that the shop does not have any qualifying operating system licenses that can be “upgraded”!

    I really hope you can help me here with the right OS product I need that comes with a volume key and is not an upgrade?

    Thanks for your article, It did help me with other questions.

    • The biggest problem I see here is that it sounds from your description as though the users of the system will not be employees of the small business. You may want to consult with someone from the Microsoft licensing team on this, but my take is that the business would need to purchase a VDA license for every user (whether contractor or employee) that would be accessing the ViaB infrastructure.

      Also, I presume that the business itself has some number of PCs, which came with OEM copies of Windows installed on them. You should be able to purchase upgrade licenses referencing those OEM licenses, and then use that volume license key to build the ViaB infrastructure.

  10. Synlap Meup on December 12, 2013 at 7:57 am said:

    I think (hope) you’ve clarified the Microsoft side of this for me - but I have two questions on the Citrix side …

    Which XenDesktop license editions (VDI, APP, Enterprise, Platinum) will allow me to deploy XenApp 6.5?

    And can I choose between User/Device and CCU XenDesktop licensing even though I am deploying XenApp 6.5?

    • The only XenDesktop edition that does NOT include the rights to use XenApp is the XenDesktop VDI edition. As the name implies, it is VDI only. The XenDesktop Enterprise and Platinum Editions include the rights to run XenApp Enterprise and Platinum (respectively).
      The big change in XenDesktop 7 is that Citrix is apparently retiring the XenApp brand. You can consider XenDesktop 7 App Edition to be the equivalent of what used to be XenApp. It does not include any of the other XenDesktop VDI components. And you can choose to “downgrade” and run XenApp v6.5 if you need to do so, even if you’ve bought XenDesktop 7 licenses.
      Regarding User/Device licensing vs. CCU licensing, you are expected to live within the EULA of the licenses you purchase. So if you purchase User/Device XenDesktop licenses, you are expected to have a license for each user or device that attaches to a XenApp server. However, up through XenApp v6.5, all XenApp really understood was the CCU license model, so there was no enforcement mechanism that would prevent you from using User/Device licenses as though they were CCU licenses if you were deploying XenApp only. However, doing so would be a violation of the Citrix EULA. I’m not certain whether such an enforcement mechanism exists in XD7 App Edition.

  11. Jeroen on October 23, 2013 at 5:04 am said:

    Hi there, thanks for this extremely useful information. However i still have a question.
    Im doing some research for a company that is looking to offer a hosted desktop solution for smaller bussines units (SMB/ Companies under 50 employees).

    So i’ve found some companies that offer services that are based on grid based architecture like VDI in the box. However i don’t have a clue how it works with the licenses.

    I understand that if the company wants the employees to work with thinclients, it has to buy VDA licenses. First question do you also need an regular OS license ( Windows7 ). I think i’ve read somewhere that it doesn’t matter how many instances of a OS you have running in your datacenter. It matters with how many devices you can connect to these virtual desktops.

    So lets say i have 30 employees with all a personal thinclient i have to buy 30 VDA licenses?

    Then CAL’s, do you need them in for example an VDI in the box solution?

    • Jeroen,

      If you’re talking about a hosted desktop solution, it gets tricky - we know, because VirtualQube is in the Desktop as a Service (DaaS) business. Microsoft does not include ANY desktop OS on the Service Provider License Agreement (SPLA). I cannot legally provide you with a Windows 7 (or Windows 8) desktop and charge you by the month for it. That’s why our service - and nearly all other services, whether they admit it or not - is actually built on Windows Server 2008 R2 with Citrix XenApp v6.5. There is a policy pack that can be applied to Server 2008 R2 that makes the desktop look and feel like a Win7 desktop, but it isn’t.

      In order for me (as a service provider) to provide a hosting customer with true Win7 hosted desktops, the CUSTOMER must purchase all the necessary licenses - meaning that either (1) the customer’s client devices must be Windows PCs with active Software Assurance, or (2) the customer must purchase VDA licenses for every client device; AND the customer mus provide me with valid Windows 7 licenses for the VMs I’m going to provide to them. Then, I have to dedicate hardware in my hosting center to that customer - the hardware I use to provide services to that customer cannot be used to provide services to any other customer. Unfortunately, that tends to skew the economics of the solution unfavorably.

      One way that some hosting providers can get around this is to provide users with individual dedicated instances of Windows 2008 R2, which, by the way, is now supported by VDI-in-a-Box. The hosting provider can report Windows Datacenter Edition licenses on their SPLA for, e.g., each server in the VDI-in-a-Box grid, which allows them to run an unlimited number of Windows Server instances on that server. Then the hosting provider just needs to track and report the Remote Desktop Services licenses for the users, and VDA licenses are simply not required, regardless of what the client device is.

      Now, that may or may not fit the business need because, even though we can make that desktop LOOK like a Win7 desktop, it still isn’t a real Win7 desktop - it’s a desktop delivered from a dedicated server instance. You also have to deal with the difficulties that are inherent in VDI-in-a-box when it comes to things like backing up and restoring user-specific data - but that’s getting off-subject for this thread…there are other posts on this blog that deal with VDI-in-a-Box, personal vDisks, etc.

      If you’d like to take this conversation off line, feel free to email me directly at sid.herron@virtualqube.com.

  12. Michael Dawson on September 19, 2013 at 10:13 am said:

    Great article btw, but i’m still not clear:

    I’ve already pretty much ruled out VDI options and I’m looking at using plain RDS. I have 140 staff, a concurrent usage of approximately 100 users, and an estate of approximately 190 windows laptops and PC’s. My people are looking to use a variety of non-Windows tablets etc. They also need to access a shared session desktop from home, and use Microsoft Office.

    Please correct me on any of the following assumptions:
    If I use RDS User CALs I can purchase 140.
    Because i’m using RDS Shared Sessions, I don’t need any VDA CALS?

    And I’m confused as hell about Windows licenses for clients:
    Do clients accessing the Shared Session require a Windows CAL?
    Does it require SA?
    What extra license do I need for Andriod Tablets to access the Shared Desktop?
    I’ve read above that MS Office is a device CAL, how on earth do I license office so that users can access the Shared Desktop Session from their home PC’s / Tablets?

    Serious thanks to anyone who can help.

    • Great questions, Michael. I’ll try to answer them:

      You are correct in that if you purchase RDS User CALs, you can purchase 140 and it will cover your users regardless of how many client devices they may use to access your Remote Desktop Servers. That’s why it is almost always better to purchase User CALs rather than Device CALs. (The exception would be for organizations that may run 24×7 and have three different shifts of users who use the same client devices.) If you are just using RDS “Shared Hosted” desktops, as opposed to attaching to a virtual instance of Windows 7, you do not need any VDA licenses.

      You will also need to have 140 Windows Server CALs (again, preferably User CALs), but you’d need those whether you were running RDS or not - simply to access services on Windows servers.

      SA is not required for any of the CALs - you have to make the call of whether the benefits of SA (like upgrade protection) justify the additional cost.

      You do not need any special license to connect to the Remote Desktop Server(s) from an Android tablet or any other kind of non-Windows client device, provided the person who is using that device has been assigned an RDS User CAL.

      Office, however, is a different story. Here is exactly what Microsoft’s January, 2013, Product Use Rights document says about desktop apps:

      1. You must assign each license to a single device.
      2. You may install the software on the Licensed Device and a network server.
      3. Unless you license the software as an Enterprise Product or on a company-wide basis, you may also install the software on a single portable device.
      4. You may use any number of copies of the software.
      5. Each license permits only one user to access and use the software at a time.
      6. Local use of the software running on the Licensed Device is permitted for any user.
      7. Local use of the software running on a portable device is permitted for the primary user of the Licensed Device.
      8. Remote use of the software running on the Licensed Device is permitted for the primary user of that device from any device or for any other user from another Licensed Device.
      9. Remote use of the software running on a network Server is permitted for any user from a Licensed Device.

      Here is how I interpret this: If I, as a user, have both a desktop PC and a laptop that I carry around when I travel (my “single portable device”), I have the right to install a single Office license on both devices. Anyone can legally use Office on my desktop PC (my “Licensed Device”), but only I (the “primary user of the Licensed Device”) can legally use it on my laptop (#6 & #7 above) - unless, of course, I had a second license to assign to the laptop, in which case it would become another Licensed Device.

      I could also use ANY device (including an Android tablet) to remotely access Office running on my desktop PC - say, via GoToMyPC - and any other user could remotely access Office running on my desktop PC provided they were connecting from another Licensed Device (#8 above). But none of the above grants me the right to access Office via RDS (on a “network server”) from anything other than a Licensed Device (#9 above).

      HOWEVER, if you have Software Assurance on your Office licenses, you get expanded roaming rights that allow the primary user of a Licensed Device to remotely access Office from a “Qualifying Third Party Device,” which is defined as a device that is not controlled, directly or indirectly, by you or your affiliates. This would include public kiosks, personal PCs / laptops, or a personal Android or iPad tablet.

      So the bottom line is that if you DON’T have SA on your Office licenses, you’re going to need to purchase an Office license that you can “assign” to that Android tablet, and/or make sure that users who are connecting from home or from the road are doing so from PCs that have Office VOLUME LICENSES or “Full Packaged Product” (a.k.a. Shrink Wrapped) licenses installed on them. (OEM licenses DO NOT include “network use rights” and therefore a PC that has an OEM version of Office installed is not entitled to access Office via RDS.)

  13. Stéphani Van Vossel on July 4, 2013 at 6:55 am said:

    what if I would want to deploy virtual desktop vm’s (xendesktop, VDI in a box) and I am working with a Linux thin client.

    won’t I need win 7 or 8 licenses as well, how will I provide these? there are only upgrades available for Win 7 since it is always in OEM attached to a laptop or pc. But in the case of thin clients, you have no OEM attached, yet you are using Windows in a virtual environment.

    Do I only need VDA in this case? it seems strange I wouldn’t need to license my windows licenses.
    can I attach a windows upgrade license of windows in this case? it does give the required keys…

    • Yes, that’s what the VDA license is for. Microsoft’s rules for licensing true VDI (by which I mean attaching to a virtualized Win7 or Win8 desktop, as opposed to a desktop delivered from a Remote Desktop Server) are pretty simple: If the client device is a Windows PC covered by Software Assurance, then you don’t need any other client-side license. If it is ANYTHING ELSE (thin client, iPad, Linux PC, or even a Windows PC WITHOUT Software Assurance), then you need a VDA license for that client device.

  14. Wayne on June 4, 2013 at 7:37 am said:

    Hi, I am just trying to clarify if I can use XenApp to stream apps direct to clients with out any extra costs.

    We have a large pool of XenDesktop Virtual Desktops running Win 7, we use a mixture of wyse terminals/pc extender and the Citrix gateway to access our virtuals. Our main delivery method for apps is MS App-V 4.6 and we are a long way off from being able to organise the upgrade to App-V 5. We also use XenApp to deliver some apps that just wouldn’t play nice with App-V (they are installed on the Xen Box direct and published as usual). I am sure our licensing is in place and valid to this point, but I am wondering if I would be able to use the Xen App Profiler and create packages to stream direct to the Virtuals (as an alternative to App-V) without needing any additional licensing (RDS Cals or likewise).

    Sorry if I am just repeating anyones previous questions, but I am a wee bit baffled by all the licenses.



    • Wayne - I have been told by Microsoft that if you are running applications via Remote Desktop Services, you need an RDS CAL. If you are not, you don’t. If you are using XenApp EXCLUSIVELY to stream application packages to client PCs (whether physical or virtual) and the application is being executed on the CLIENT and not on the XenApp server, then you do not need an RDS CAL.

  15. christabelle on May 27, 2013 at 3:42 am said:

    .hi Sid, thanks so much for this, pls I am looking at the situation where we have VDI, not publishing (streaming) apps over Xenapp. Will we need a license for 1000 VDIs being delivered to 1000 thin clients.

  16. First and foremost, thank you very much for this article, it’s very clear and helpful.

    Licensing once it’s right, it’ can be relatively easy to maintain but if you are starting from scratch or rebuilding an infrastructure, it can be a mine field.

    I think the issue that most people find is that the documentation is too hard to read as there is too much of it, specially in complex scenarios. Secondly, MS normally want you to go through a reseller if you don’t have a presence and that can be very frustrating for the smaller businesses.

    I’m just going to add to your VDA information. VDA licensing is only applicable when you access a dedicated Windows 7.XP desktop and not a shared desktop. Therefore a VDA license is applicable when a user is using a VDI platform such as XenDesktop/VMware View but not applicable when using RDS/XenApp. It is still bloody ridiculous though, as you are already paying a fortune for various licenses and this is an ongoing cost per annum, so if you are lucky enough like the guy deploying 850 desktops, that’s another 85k per annum (might be discounts available at such volumes) on MS licensing if using VDA, but if you were using XenApp, you would not have this. (this is of course, if you are using thin clients as in the scenario above)

    Then you have the CDL licenses, this is a joke.

    Unfortunately licensing is very difficult.

    I could rant forever on this topic, but I found this post very helpful and I hope it helps many others.

    • I have a scenario where users will be using a win 7 vdi hosted by a partner.I have a xenapp 6.5 farm and I need to stream ie 7 to my 100 users using the hosted vdi..how many licenses I need of xenapp.Partner is responsible for the xendesktop vdi license..as its his vdi..

      • I’m not entirely clear on the architecture here. Where will IE7 be running? You mention “hosted VDI.” Are you streaming IE7 all the way to the Win7 virtual desktops that are hosted somewhere else, or on, say, virtual WinXP instances on your own infrastructure? What kind of network connection do you have between the partner’s infrastructure and your own?

  17. CMcNally on January 11, 2013 at 6:28 am said:

    We are planning to deploy a second XenApp Server, clients currently use CAG to connect to one XenApp Server, we present them with a desktop and they execute applications on the server.
    So to get our licensing straightened out for this new installation, we need:
    Windows Server 2008 R2 license
    Windows Server CAL for each user
    RDS CAL for each user
    Citrix XenApp license for each user

    Are we correct? Seems like we have one too many…

    • Yes, you are correct, with one clarification: XenApp by itself is still licensed based on the maximum number of CONCURRENT users you need to support. Microsoft CALs, on the other hand, must be purchased for each unique user (or device - but device CALs seldom make sense anymore). If your concurrency ratio - by which I mean the total number of users who would ever log onto the XenApp server compared to the maximum number of users you would expect at any given time - is 2:1 or less, then it would be more cost-effective to purchase XenDesktop User licenses, which include the rights to run XenApp, but are half the cost of XenApp concurrent-use licenses. We frequently sell XenDesktop licenses to customers in this situation even when they have no intention in the near term of actually using anything but XenApp, simply because it’s less expensive.

  18. Hi there - I didn’t see MS Office for Service Providers covered - can you provide a response for the following scenario?

    A Service Provider installs MS Office in VM to be used by XenApp.

    The end-users are Customers of the Service Provider and will access the apps from within the browser.

    How is the MS Office license managed and charged?


    • Well, we’ve gone rather far afield from where this post began. But the short answer is that, under the terms of the Microsoft Service Provider License Agreement (SPLA) - and I’m assuming here that the service provider in question does have a SPLA in place - the service provider is required to track and report, on a monthly basis, the number of users who have accessed the applications. The service provider pays Microsoft monthly according to the terms of the SPLA agreement. It’s up to the service provider how (and how much) they charge their customers.

  19. Niten Verma on January 5, 2013 at 3:59 am said:

    we want to use windows 2012 as SAP Server with oracle database , if we use sapgui client on ubuntu client to access SAP Server , do we need CAL License for clients?

    Thanks in advance

    • Niten,
      Any time you are accessing a Windows Server for anything, you need a Windows Server CAL (with the exception of a public-facing Web server that’s just serving up Web pages). That said, the definitive resource for information would be the Microsoft Product Use Rights document.
      -Sid Herron

  20. Pingback: VDI Ready » Blog Archive » How Citrix XenDesktop per user/device licenses work

  21. Hi Sid,
    That’s a great article, very clear and useful.
    Thanks very much for the share and the time you spent to write this.

  22. Hi Sid,

    Great article!

    A quick question that I am fighting a couple of others with…. In a Citrix environment where there are 45 users connecting remotely, am I right in assuming that each of those users (devices) still need the identical office license as is used on the Appserver? In a MS RDS environment ANY device that CAN connect to the server HAS to have an office license, and Im sure this is the same for Citrix, but a discussion is ongoing where I’m being told that a Citrix solution can share 10 office licenses……… I know (i’m sure…) thats a crock of crap but would like it confirmed if possible. Is there a way to share licenses…….?


    • Great question, Paul, and I actually wrote an entire article about it a couple of years back. To put it briefly, Office is a device-based license, not a user-based license, and Microsoft’s position is that you need an Office license for every device that is used to interact with Office apps - regardless of whether the Office Suite is installed locally on that device, or whether you are accessing it via Terminal Services. I would encourage you to read the entire post I referenced earlier, and, of course, the definitive source is always the Microsoft Product Use Rights document.

  23. Hi There,

    I’m new to RDS, Citrix etc but my company is about to roll-out several hundred thin-clients (850). We have haven’t yet made a decision on which device yet but the 3 options seem to be either a Wyse zero or thin client, a HP t410 all-in-one or a device with WES7 installed. We will not be provisioning virtual desktops, just a couple of applications either by publishing them in RDS (or using Xenapp) or by serving out a full RDS desktop (is the Citrix version XenDesktop).

    Can you please explain what licensing I would need for that set up?

    • Hi, Craig,

      If I’m understanding you correctly, even though you’re using XenDesktop licensing, you’re actually going to be using XenApp/Remote Desktop Services to deliver either hosted desktops or published applications. If I’m correct on that, they you will need both Windows Server CALs and RDS CALs. In most cases, User CALs are more cost-effective, because they entitle a user to connect to a XenApp/RDS Server from multiple client devices. In some cases, Device CALs may be more cost-effective - an example might be a hospital that runs around the clock, and has multiple users who use the same client device to access the XenApp/RDS Server(s). It is theoretically possible to mix User and Device CALs within a single environment, but not recommended, because it is quite difficult to manage. Each individual XenApp/RDS server must be configured to request either User CALs or Device CALs (not both) from the Microsoft license server - so you would have to maintain two separate groups of servers, and then figure out how to direct different kinds of connections to the right group of servers. We have never deployed a mixed environment of User and Device CALs for that reason.

      Good luck with your deployment!

      • Hi There,

        Thanks for the reply but that’s not exactly what I was intending. The truth is we haven’t yet made a decision on whether to use Citrix or just plain old RDS, nor have we made a decision on how to serve the applications out. I don’t much about Citirx but with RDS you have the option to either publish the application (i think Xen app is the Citrix equivalent) or serve out a full desktop (i presume XenDesktop is the Citrix equivalent) from the session hosts.

        If we just went with plain RDS and zero/linux clients would we only need device/user RDS CALS, i.e. no VDA license?

        Also, if we went with Windows 7 WES or Windows 7 Embedded compact would we also need VDA licensing?

        • OK, let me see if I can clarify. First, XenApp is a set of extensions and enhancements to Remote Desktop Services. So, if you are going to have users accessing desktops and/or applications on a Remote Desktop Server, then you will need RDS CALs as I described in my earlier comment, regardless of whether or not XenApp is added to the environment.

          Also, the RDS CAL is required regardless of what the client device is: PC, thin client, zero client, WES or Win7 embedded, iPad, Mac, etc.

          VDA licenses are not required if you’re accessing an RDS server - they are only required if you are accessing virtual instances of WinXP or Win7, AND your client device is something other than a desktop PC that’s covered by Software Assurance.

          If you decide that the XenApp feature set brings value to what you’re doing, then you have some choices about how to license the Citrix side of things:

          You can still purchase XenApp licenses, which only give you the rights to run XenApp. Unlike the Microsoft license requirements, XenApp is licensed based on the number of CONCURRENT users you will need to support.

          Your other option is to purchase XenDesktop licenses, which give you the rights to run any mixture you please of XenDesktop, XenApp, and XenClient. XenDesktop can be licensed per named user or per concurrent user. Because the named-user XenDesktop license is half the cost of the concurrent-user XenApp license, customers will often purchase XenDesktop licenses even when all they need to deploy today is XenApp…unless they have a “concurrency ratio” (number of total users to number of concurrent users) that is significantly greater than 2-to-1.

  24. Carl Schneider on November 13, 2012 at 5:51 pm said:

    Sid, do I need Windows 7 licenses for each of my XenDesktop accounts? If not, how does that licensing work?

    • Carl, at present, Microsoft provides only two ways to legally license access to a virtual instance of a Windows desktop: (1) The client device you are using to access the VM is a Windows PC covered by Software Assurance, or (2) You have a VDA (Virtual Desktop Access) license for that client device. The VDA is currently only available through the Open Value Subscription model, which is an annual subscription that costs approximately $100/year/device. Like most Microsoft licensing, there is no enforcement mechanism that I am aware of, other than your desire to remain in license compliance (and the likelihood of getting smacked down if you’re ever audited and found not to be in compliance).

  25. Can u tell me where i find this information:
    You do not need an RDS CAL if you are only using XenApp to stream packaged applications to a virtual (or physical, for that matter) desktop for execution there”

    I only found that i need a RDS CAL and a concurrent XenApp Cal for one connection ….

    • Andre - I specifically asked a Microsoft licensing specialist. An RDS CAL is required if you are accessing Remote Desktop Services to remotely execute applications on a server. If you are only using XenApp to manage the streaming of packaged applications, then you are not using Remote Desktop Services to execute applications, and therefore are not required to have an RDS CAL for your streaming target.

      • Hi
        I need to stream Microsoft outlook to my vdi users from xenapp..do I still need microsoft office license..assume if they are using outlook web access. .in this case I m streaming only ie8 to users

  26. I thank you Sid for a really well written and complete clarification of this subject!. You are Brilliant!

  27. Prince Cassius on May 20, 2012 at 4:13 pm said:

    Koodos!! for this is about the best clarification on Microsoft & Citrix licensing I have stumbled upon on the net yet. One only question i have is what about windows embedded thin clients? If you bought those will one still be subjected to buying vda licenses?


    • Yes, Windows Embedded thin-clients still require a VDA license, because they are not eligible for Software Assurance coverage. That’s why, as we pointed out in an earlier post (http://www.mooselogic.com/blog/thin-clients-vs-cheap-pcs), it can sometimes be less expensive in the long run to buy a low-end PC than to buy a thin-client device…although arguably the thin-client device will probably be easier and less expensive to maintain over time, and will definitely be a better choice for a hostile environment.

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