CAL License

Hello Forum Members, 

I'd like to understand the role of CAL and RDS CAL licenses in Virtualization hardware (Thick Client, Thin Client, Virtualization Domain Controller, and Host Servers)

Rishi

• 19 Dec 2024 7:26 PM
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4 Replies

• Andre Dicaire

  

  • 20 Dec 2024 1:44 AM

  Wouldn’t we all?!! Here’s what understand, to get the ball rolling.
  CAL licenses cover access to servers by client stations, ie Win10 client OS. When a client application on your workstation connects to a server the CAL license covers this. Each client needs the CAL. So if you have three servers each purchased with five CAL licenses, you have a total of fifteen clients that can connect to any or all the servers. If you had a workgroup with no server OS machines, you don’t need CALs. But in a Domain you have a DC server at least. So CALs for everyone.
  
  RDS CALs are required to open a Remote Desktop session on the RD server. These cals are loaded in the license server for the RD server to use. They can be node based or user based. DeltaV Remote Client server is an RD server and installation instructions enable a local license server on the same computer and RDS CALs are loaded.
  
  RD Servers were used by none DeltaV computers referred to as Thick clients when they ran a full version on Windows 10. These require software assurance that covers the client to use RDP. They can be RDP CAL licenses the session.
  
  With virtualization, Win10 VMs are paired with Thin clients. Thin clients require VDA license that covers the use of RDP on these client side stations which are not eligible for software assurance coverage.
  
  VDA licenses are issued as a documented proof and do not get loaded or enforced in any way. A system audit would reveal the use of RDP by thin clients and the user would need to show these license to be in compliance.
  
  VDA(Virtual Desktop Access) is part of Microsoft VDI (Virtual Desktop Infrastructure). The VDA license provides access to activation codes for the Windows 10 VM it will connect to and is provided sa a subscription. Emerson has recently become able to offer a one time license for DeltaV thin clients which replaces the VDA subscription( nice improvement in my Opinion).
  
  Emerson also calls for RDP CALs for these thin clients because they too use RDP connections to the Win10 VMworkstations. However the workstations do not connect to a license server and the RDP connection is to the console session or session 0. What do you do with those RDP CALs? If you don’t have an RDP server/license server, you can hang on to them. If you use the Thin Client to access an RD server session you definitely need the session to be licensed. So each Thin Client needs VDA (or new perpetual version) and an RDPcal. The Win 10 VM needs the CAL as it is running on a server, likely has an IDDC for authentication and if the Pro Plus or an app station are on Server OS.
  
  Now someone please check my answer, please.

  Andre Dicaire

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• Rishi

  

  • 21 Dec 2024 11:59 AM

  In reply to Andre Dicaire:

  Andre, Thanks for your reply.

  Emerson has recently become able to offer a one-time license for DeltaV thin clients Client OS Virtual Machines and not for the thin clients that replace the VDA subscription.

  In the DeltaV Virtualization Microsoft Licensing Guidelines, Client VMs can be licensed through VDA or Emerson-offered Microsoft Client license.

  Per the guidelines, a Client VM would require 2 Microsoft Client licenses, one for the primary host and another for the failover host. How does this work in real-time when Win 10 client VM failover from primary to this failover host?

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• Andre Dicaire

  

  • 7 Jan 2025 8:14 PM

  In reply to Rishi:

  I'm looking into this some more. I may be under licensed...
  
  I found an internal license document that explains that with VDA, a single VDA license covers the fail over VM, but the Emerson Offered Microsoft Client license is required for each VM of a Fail over pair. As explained to me, the new license is to replace the VDA and takes you to the same licensing facility as VDA, but the document clearly states two are needed as opposed to one VDA.

  Andre Dicaire

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• Andre Dicaire

  

  • 8 Jan 2025 8:01 PM

  In reply to Andre Dicaire:

  To your specific question about the new Emerson Client OS Access (COA?) license, Emerson provided an example license exercise with 8 VDI VM's that have Failover defined, ie 16 Windows 10 LTSC VMs in total across a two host HCI.
  
  VDA: A total of eight (8) VDA subscription licenses are required as each VDA license covers the two instances of the VM.
  
  COA: A total of sixteen (16) COA perpetual licenses are required, one for each VM instance.
  
  I discussed this with our system tech and he told me the COA comes as a sticker with the activation code on it. Emerson told me the COA gives you access to the same license site as VDA where you get your activation code. Either way, the activation code is needed to activate the OS. This propagates to the failover instance and to any replicated instance. The license however is what grants you the legal right to use a VM. VDA grants you that right for multiple instances of the VM. COA grants you the right to one instance. So when you buy two COA licenses, you will get two Activation codes, but you only need one activation code. You need two COA to legally set up the failover instance.
  
  Emerson was obligated by Microsoft to have customers provide proof of VDA licensing before Emerson could ship Client OS VM Templates. With the COA, this is no longer required. This makes ordering the DeltaV Virtual Studio and associated templates easier. Is there a use case to still use VDA? Since VDA is subscription, any temporary setup would benefit from the lower cost of a short term VDA license rather than perpetual license of COA. Since DeltaV Development systems and now Simulate Systems are all available by subscription, managing VDA subscriptions as part of this is not a big deal. For production installations, even if the VDI has failover and you need two COA licenses, the long-term operation of the VM means it will cost less with COA, A Pilot plant could start with VDA and transition to COA if the plant transitions to full production. If it is decommissioned in a year or two, VDA might be a better option.

  Andre Dicaire

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