More on Microsoft Product Terms: Per Core/CAL, Server/CAL and Per Core

By Dan Brewster

Director of Client Services, Microsoft, NPI

November 15, 2018

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As part of our continuing discussion on Microsoft Product Terms, let’s focus on the following popular licensing models: Per Core/CAL, Server/CAL and Per Core. Note: This post is third in a series on the terms and conditions found in Microsoft’s Product Terms document – be sure to check out my previous posts here and here.

The Per Core/CAL model is relatively new to Microsoft and was designed to support the recent licensing changes in the Windows Server and Core Infrastructure Server products. Prior to Windows Server 2012, Microsoft licensed the Windows Server product on a true Server/CAL basis – you buy a license for each server, and sufficient Client Access License for each unique user or device. With the 2012 product, Microsoft moved to a Per Processor model. But then Moore’s Law intervened and Microsoft realized it would be more cost advantageous (for Microsoft) to move to a Per Core model. This model requires that you license each physical core on the server. The company will tell you that there was no cost increase when moving from a Processor to a Core model, yet this doesn’t consider the likelihood that large servers will have core-dense processors that will require additional Core licenses.

Microsoft offers a transition of 1 processor to 8 cores, with a minimum of 8-cores per processor and 16-cores per server for the Windows or CIS Server products (this applies to both the Standard and Datacenter versions). This is all good and well unless you are running 20-24-32 or more cores on a processor. Microsoft will provide a license grant if this is the case, yet you’re still responsible for paying for Software Assurance for the total core count. Said another way, this is the cost increase for your Windows Server. We believe it will be likely that most customers will experience a price increase as they upgrade servers in the future.  This model still requires a Client Access License for each user or device.

The Server/CAL model is one of Microsoft’s more simple licensing models – a server license is required for each server, and a Client Access License is required for each unique user or device accessing the server. As discussed in another blog in this Microsoft Product Terms series, it is important to note that multiplexing devices do not reduce the number of Client Access Licenses required.

The Per Core model is designed for products like Biztalk, System Center, and SQL Server. No Client Access Licenses are required under this model, which makes it great for those customers that wish to provide external access to these servers. External access is defined as access by non-employees or non-on-site consultants. This model facilitates licensing in either the physical or virtual environment, with different rules for each environment. SQL, for example, this requires you to license all of the physical cores on the server with a Core based license. If you are licensing on a virtual basis, each virtual machine must have a minimum of 4 Core licenses assigned to the VM. If you happen to be licensing the SQL Enterprise product, and you license all of the physical cores on the server, Microsoft will provide unlimited virtualization for SQL Enterprise.

The License Model Terms include the nuances of how to license Microsoft’s intellectual property. It’s important to note that a keen understanding of these license models is required to ensure that you remain compliant with Microsoft’s product use rights.