Determining Product Key Needs

The Windows 7 and Windows Server 2008 R2 operating systems come in a variety of editions. To simplify Volume Activation and the number of product keys that an organization needs, Microsoft created product key groups, where product keys apply to product groups rather than individual editions.

Choosing the KMS Key

With KMS, product keys are associated with a product group and can activate the Windows editions within that specific product group as well as any editions lower in the product hierarchy. The first and least-inclusive group of the hierarchy is the Client Volume Licensing product group; Server Group C is the most inclusive group in the KMS hierarchy.

This hierarchy extends to Windows Vista and Windows Server 2008 Volume Licensing editions and product key groupings. Separate KMS keys will be issued for each product key grouping, meaning that a customer will have access to a KMS key for Client VL for both Windows 7 and Windows Vista. The KMS key for the newer Windows products will also activate the previous generation, meaning that a customer can have a single KMS key to activate multiple editions and generations of Windows. Table 1 shows the correlation between the product groupings.

Table 1. Product Group Correlation

Volume License product key group	Windows edition (Windows 7 and Windows Server 2008 R2)	Windows edition (Windows Vista and Windows Server 2008)
Client VL	Windows 7 Professional Windows 7 Enterprise	Windows Vista Business Windows Vista Enterprise
Server Group A	Windows Web Server® 2008 R2 Windows Server 2008 R2 HPC Edition Windows HPC Server 2008 R2	Windows Web Server 2008 Windows Compute Cluster Server 2008
Server Group B	Windows Server 2008 R2 Standard Windows Server 2008 R2 Enterprise	Windows Server 2008 Standard Windows Server 2008 Enterprise Includes editions without Hyper-V™
Server Group C	Windows Server 2008 R2 Datacenter Windows Server 2008 R2 for Itanium-Based Systems	Windows Server 2008 Datacenter Windows Server 2008 for Itanium-Based Systems Includes editions without Hyper-V

Choosing the KMS Host

As previously mentioned in this guide, KMS can be hosted on a client or server operating system on a physical computer or a virtual machine. When choosing the KMS host system, consider the operating system editions that will be activated with KMS. A KMS that is hosted on Windows 7 can only activate client operating systems , but a KMS that is hosted on Windows Server 2008 R2 can activate both client and server computers. See Table 2 for an explanation of this hierarchy.

Table 2. KMS Hierarchy

Product key group	KMS can be hosted on (KMS key activates KMS host)	Windows product editions activated by this KMS host
Client VL for Windows 7	Windows Vista Windows 7 KMS for Windows Server 2003 1.2	Windows 7 Professional Windows 7 Enterprise Windows Vista Business Windows Vista Enterprise
Server Group A for Windows Server 2008 R2	KMS for Windows Server 2003 1.2 Windows Web Server 2008 Windows Web Server 2008 R2 Windows HPC Server 2008 Windows HPC Server 2008 R2	Includes previous plus: Windows Web Server 2008 R2 Windows Web Server 2008 Windows HPC Server 2008 R2 Windows HPC Server 2008
Server Group B for Windows Server 2008 R2	Includes previous plus: Windows Server 2008 R2 Standard Windows Server 2008 R2 Enterprise Windows Server 2008 Standard Windows Server 2008 Enterprise	Includes previous plus: Windows Server 2008 R2 Standard Windows Server 2008 R2 Enterprise Windows Server 2008 Standard Windows Server 2008 Enterprise
Server Group C	Includes previous plus: Windows Server 2008 R2 Datacenter Windows Server 2008 Datacenter Windows Server 2008 for Itanium-Based Systems	Includes previous plus: Windows Server 2008 R2 Datacenter Windows Server 2008 Datacenter Windows Server 2008 for Itanium-Based Systems