Windows Server is a server operating system that enables a computer to handle network roles such as print server, domain controller, web server, and file server. As a server operating system, it is also the platform for separately acquired server applications such as Exchange Server or SQL Server.
You can use this guide to find the Windows Server edition and licenses appropriate for your organisation's needs.
Microsoft offers Windows Server through Connecting Up in the Standard, Datacenter, and Essentials editions. The Standard and Datacenter editions share most of the same features; the primary difference is the number of virtual instances of the server software you are allowed to run. Essentials shares many of the features of the Standard edition, but has limitations on the maximum number of users and devices that can connect to it.
- The Standard edition is designed for small-to-medium-sized organisations. It allows you to run two instances of the server software in a virtual operating system on the licensed server. If you need to run additional virtual instances, you can acquire more Standard licenses.
- The Datacenter edition is optimized for large-scale virtualisation. It allows one server to run an unlimited number of Windows Server instances. It includes all the features of the Standard edition as well as support for encrypted virtual machines, software-defined networking, and software-defined storage.
- The Essentials edition is designed for small organisations with up to 25 users and 50 devices. It allows only one instance of the server software to be run in the physical or virtual environment (Essentials edition licenses can't be combined). Client access licenses (CALs) aren't needed.
The Standard and Datacenter editions of Windows Server 2016 use a combination of core-based licensing and CALs. Previous versions of Windows Server have also been transitioned to this licensing model.
- Both editions require a minimum of 8 core licenses for each physical processor and a minimum of 16 core licenses for each server.
- The products offered by Connecting Up provide two core licenses. Microsoft donation rules allow you to obtain up to 50 core licenses by requesting up to 25 products from the Windows Server title group per two-year cycle.
The Essentials edition does not use core-based licensing and does not require CALs. However, it can only be used on a single server with a maximum of two physical processors.
For more detailed licensing information, see the Windows Server 2016 licensing datasheet (PDF).
Client Access Licenses and External Connector Licenses
Windows Server Standard and Datacenter editions require a Windows Server user or device CAL for each user or device accessing or using the server software. No CALs are needed for the Essentials edition, which means the maximum of 25 users and 50 devices can't be exceeded.
Alternatively, an organisation can use a Windows Server external connector license (ECL) for a large number of authenticated external Internet users. An external user is a person who is not an employee or someone to whom you provide hosted services using the server software. No CALs are needed for anonymous Internet users, such as unidentified users browsing the organisation's public website.
CALs and ECLs offered through Connecting Up are always for the currently offered version of the server software. However, these licenses can also be used with earlier versions of the server software.
Remote Desktop Services
If the server is running Remote Desktop Services (previously known as Terminal Services), separate Remote Desktop Services CALs or ECLs are required to access the services. Remote Desktop Services allows the remote execution of applications from a wide range of devices over virtually any type of network connection.
Remote Desktop Services CALs are different from other Windows Server CALs because they require a license key from the Microsoft Volume Licensing Service Center (VLSC) for installation. See Microsoft's requirements and instructions for installing Remote Desktop Services CALs.
Rights Management Services
If the server is running Rights Management Services (RMS), separate RMS CALs or ECLs are required to access the services. RMS is information-protection technology that works with RMS-enabled applications to help safeguard digital information from unauthorized use. RMS functionality is included in the Windows Server license.
RMS licensing is not available through Connecting Up.
Server Application Licenses
Licenses for server applications — such as SQL Server or Exchange Server — that run on the Windows Server platform are separate. General licensing requirements for server applications offered through Connecting Up can be found in the product descriptions. For details, see the Microsoft Product Use Rights documents.
If you have earlier versions of Windows Server with active Software Assurance, you can upgrade to Windows Server 2016 without placing a new donation request. Since Windows Server 2016 has changed to a core-based licensing model, organisations with Software Assurance will be granted a certain number of core licenses, depending on how many processor licenses they have. See the Windows Server 2016 licensing datasheet (PDF) for details.
For help upgrading, see Windows Server installation and upgrade information in the Windows Server TechNet Library.
If you upgrade to Windows Server 2016, you will also need to use Software Assurance to upgrade your CALs.
Downgrade rights allow you to obtain Windows Server in any version that Microsoft continues to make available for download through the Volume Licensing Service Center. With Windows Server, you can choose to download the 2016, 2012 R2, or 2012 versions of the edition you've licensed. Downgrading does not depend on Software Assurance; it is a benefit of Volume Licensing.
However, with the release of Windows Server 2016, all previous versions of Windows Server have been transitioned to the new core-based licensing model. If you are planning on requesting new or additional licenses for a previous version of Windows Server, make sure you get enough licenses to cover all the cores on your licensed server according to Windows Server 2016 licensing guidelines. See the Windows Server 2016 licensing datasheet (PDF) for details.
CALs obtained through Connecting Up will work with the downgraded version.
Detailed Licensing Information
For detailed licensing information, see the Windows Server 2016 licensing datasheet (PDF) and the pricing and licensing FAQs (PDF). (Pricing information does not apply to Microsoft products available through Connecting Up.)
Complete licensing information can be found by clicking the Download the current PUR document link on the left side of the Microsoft Product Use Rights page. Select the English language link from the list.
Windows Server Products Available Through Connecting Up
See the Windows Server donations available through Connecting Up.