Inquiry regarding Windows Server 2025 Editions, Licensing Models, and RDS Requirements for 5 Users

Hamidreza Bidgoli 0 Reputation points
2026-06-06T10:38:21.36+00:00

Body: Dear Microsoft Support / Community Team,

I am currently planning a deployment using Windows Server 2025 and would appreciate some clarification regarding its available editions, licensing structures, and specific requirements for Remote Desktop Services (RDS).

Could you please provide insights on the following questions:

Editions & Differences: What are the official editions available for Windows Server 2025, and what are the primary technical and licensing differences between them?

Traditional vs. Subscription Licensing: How does the traditional core-based perpetual licensing model compare to the new Pay-as-you-go subscription model via Azure Arc?

CAL Requirements in Subscription Model: If I opt for the Pay-as-you-go subscription model, is it true that standard Base CALs (Client Access Licenses) are no longer required?

Remote Desktop Scenario: I have a specific scenario where 5 distinct clients need to connect to a single Windows Server 2025 machine simultaneously via Remote Desktop.

What exact licenses (Server core licenses, Base CALs, and RDS CALs) do I need to purchase under the traditional model?

  How would this RDS requirement change if I use the Azure Arc Pay-as-you-go subscription model instead? Should I buy User CALs or Device CALs for this setup?

Thank you for your time and guidance.

Best regards, [Hamidreza Bidgoli]

Windows for business | Windows Server | User experience | Remote desktop services and terminal services
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  1. Quinnie Quoc 11,830 Reputation points Independent Advisor
    2026-06-06T12:10:53.16+00:00

    Hello Hamidreza Bidgoli,

    Windows Server 2025 is offered in the same core editions as previous releases: Standard and Datacenter. The technical differences remain consistent—Standard is limited in virtualization rights (two VMs per licensed host), while Datacenter allows unlimited virtualization and includes advanced features such as Storage Replica and Shielded VMs. Licensing is still core‑based, with a minimum of 16 cores per server and 8 cores per processor.

    Microsoft now also provides a subscription model via Azure Arc. In this model, you register the server with Azure Arc and pay per core per month. The key distinction is that traditional Client Access Licenses (CALs) are not required in the subscription model; access rights are included in the subscription fee. However, Remote Desktop Services CALs are still required if you plan to use RDS, regardless of licensing model.

    In your scenario with five distinct clients connecting simultaneously via RDP, under the traditional model you need to license the server cores (minimum 16), purchase five Windows Server Base CALs, and five RDS CALs (either User CALs or Device CALs depending on whether the same devices are shared or each user has their own). Under the Azure Arc subscription model, you would still need the RDS CALs, but you would not need the Base CALs. The choice between User CALs and Device CALs depends on whether the five connections are tied to individual users or shared devices; User CALs are generally more flexible in modern environments.

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  2. AI answer

    2026-06-06T10:38:46.89+00:00

    Windows Server 2025 editions, licensing models, and RDS requirements are only partially covered in the provided context. The following summarizes what is documented there and how it applies to the described 5‑user RDS scenario.

    Edtions & differences (what is covered)

    The comparison article for Windows Server editions (including Windows Server 2025) indicates:

    • Windows Server 2025 is available at least in Standard and Datacenter editions.
    • Some roles/features are edition-dependent, for example:
      • Certain capabilities (such as specific clustering and advanced virtualization features) are tied to Datacenter.
      • Some features are “Available with Windows Server 2025 Standard, and are designed for standalone servers. Live migrate VMs between standalone nodes for planned downtime. If clustering is required for unplanned downtime, Windows Server 2025 Datacenter must be used instead.”
      • Some management features are “Available for machines enrolled in Windows Server Management enabled by Azure Arc with Windows Server licenses that have active Software Assurances or Windows Server licenses that with active subscription licenses.”

    The context does not provide a full, detailed edition matrix for Windows Server 2025 beyond these high‑level notes.

    Traditional vs. Pay‑as‑you‑go (Azure Arc) licensing

    The context explicitly describes Windows Server Pay‑as‑you‑go with Azure Arc for Windows Server 2025:

    • Pay‑as‑you‑go is an alternative to conventional perpetual licensing for Windows Server 2025.
    • It is enabled through Azure Arc and billed via an Azure subscription.
    • It applies to devices deployed outside Microsoft Azure (it is not supported on Azure itself).
    • Billing continues until Pay‑as‑you‑go is disabled or the device is removed from Azure Arc.
    • Pricing and model match Windows Server licensing on Microsoft Azure, but for non‑Azure devices.
    • The Pay‑as‑you‑go license only applies to the exact device where it is enabled; it does not extend to other VMs on the same host, and AVMA is not available. Each VM requires its own license.
    • Host and VMs can run different OS versions and mix different license types.

    The context does not provide detailed mechanics of the traditional core‑based perpetual model for Windows Server 2025, only that Pay‑as‑you‑go is an alternative to “conventional perpetual licensing.”

    CAL requirements in the Pay‑as‑you‑go model

    The Pay‑as‑you‑go article states:

    • “Pay‑as‑you‑go regulations differ from traditional perpetual licensing. For instance, in Pay‑as‑you‑go, the cost is the same for both Standard and Datacenter editions, and there are no client access licenses (CALs) required for standard functionality. However, Remote Desktop Services (RDS) CALs are still required.”

    From this, the documented points are:

    • Under Pay‑as‑you‑go via Azure Arc, base Windows Server CALs are not required for standard server functionality.
    • RDS CALs remain required for Remote Desktop Services.

    RDS CAL and version compatibility

    The RDS CAL documentation and supported configuration guidance provide the following:

    • RDS CALs must be compatible with the Windows Server version of the RD Session Host:
      • Later‑version RDS CALs can access earlier‑version session hosts, but not vice versa.
      • For example, Windows Server 2025 RDS CALs can be used with session hosts running Windows Server 2025, 2022, 2019, or 2016.
    • Compatibility matrix (session host vs. RDS CAL):
      • For a Windows Server 2025 session host, only Windows Server 2025 RDS CALs are supported.
    • The RDS license server must also be on a compatible Windows Server version:
      • A Windows Server 2025 license server can host RDS CALs for Windows Server 2025, 2022, 2019, and 2016.
      • A Windows Server 2022 license server cannot host Windows Server 2025 RDS CALs.
    • Best practices for RDS infrastructure:
      • Use the most recent Windows Server version for RDS infrastructure roles (Web Access, Gateway, Connection Broker, license server). Windows Server is backward‑compatible for these components.
      • All RD Session Hosts in a collection must be at the same OS level.
      • “An RDS license server can only process client access licenses (CALs) from the same or previous versions of Windows Server. So, if you upgrade your RD Session Host to Windows Server 2025, you also need to upgrade the license server.”

    RDS licensing model (per user/per device)

    The RDS payment model article states:

    • RDS can be licensed per user or per device:
      • Per user: enables users to connect from any of their devices (BYOD scenarios).
      • Per device: appropriate when multiple users share the same devices.
    • Service providers can use per‑user subscription licenses (SALs) for a pay‑as‑you‑go model.

    Remote Desktop scenario: 5 clients to one Windows Server 2025

    The context does not provide a complete, authoritative breakdown of all Windows Server 2025 server core licensing and base CAL requirements for the traditional model. It does, however, provide enough to state the following for RDS and the Pay‑as‑you‑go model.

    1. Traditional model – RDS requirements for 5 simultaneous RDP users

    From the RDS CAL and supported configuration guidance:

    • The RD Session Host is Windows Server 2025.
    • Therefore, Windows Server 2025 RDS CALs are required for the users or devices that connect.
    • An RDS license server capable of hosting Windows Server 2025 RDS CALs is required; this must be running Windows Server 2025.
    • RDS CALs can be per user or per device, and the choice depends on whether the same users connect from multiple devices (per user) or multiple users share a small number of devices (per device).

    For 5 distinct clients connecting simultaneously to a single Windows Server 2025 via Remote Desktop under the traditional model, the documented RDS requirements are:

    • An RDS deployment with:
      • A Windows Server 2025 RD Session Host.
      • A Windows Server 2025 RDS license server.
    • 5 Windows Server 2025 RDS CALs, either:
      • 5 RDS User CALs (if licensing per user), or
      • 5 RDS Device CALs (if licensing per device).

    The context does not provide explicit detail on the exact number or structure of Windows Server core licenses and base Windows Server CALs for this scenario under the traditional model.

    1. Pay‑as‑you‑go via Azure Arc – RDS requirements for the same scenario

    From the Pay‑as‑you‑go article and RDS licensing guidance:

    • When using Windows Server Pay‑as‑you‑go with Azure Arc:
      • No base Windows Server CALs are required for standard functionality.
      • RDS CALs are still required for Remote Desktop Services.
    • RDS CAL version compatibility and infrastructure rules remain the same:
      • A Windows Server 2025 RD Session Host still requires Windows Server 2025 RDS CALs.
      • The RDS license server must be Windows Server 2025 to host those CALs.
    • The per‑user vs. per‑device choice for RDS CALs remains based on usage patterns (BYOD vs. shared devices), not on whether the underlying Windows Server license is perpetual or Pay‑as‑you‑go.

    Therefore, for 5 distinct clients connecting to a Windows Server 2025 machine licensed via Pay‑as‑you‑go with Azure Arc:

    • The server itself is licensed via Pay‑as‑you‑go (no base Windows Server CALs required for standard functionality).
    • For RDS, the requirements are the same as in the traditional model:
      • A Windows Server 2025 RD Session Host.
      • A Windows Server 2025 RDS license server.
      • 5 Windows Server 2025 RDS CALs, either:
        • 5 RDS User CALs, or
        • 5 RDS Device CALs.

    The choice between User CALs and Device CALs is determined by whether the environment is user‑centric (users connect from multiple devices) or device‑centric (multiple users share a small number of devices), as described in the RDS payment model guidance.

    References:

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