Guide to Microsoft Servers and Licensing
Published on May 23, 2011
This page is an overview of Micrososft server licensing. The links on the right provides information published on the TechSoup and Microsoft sites that will help you understand the range of Microsoft servers and licenses available for donation through TechSoup.
For detailed licensing information, you can use Microsoft's Product Licensing Search page. On that page, the Product Search tab allows you to see licensing information for individual products and product families and the Document Search tab allows you to download the current Product Use Rights (PUR) document.
Licensing Models
To determine which licenses your organization needs when implementing a specific server product, you should understand the specific licensing requirements for that server. This section is a brief overview of the basic licensing models. See also the Licensing Model Categories section on Microsoft's About Licensing page.
- Server Operating Systems and Server/CAL
- The Server Operating Systems and Server/CAL models include server licenses, client access licenses (CALs) for users or devices with connections to the servers, and optional external connector licenses for connecting people who are not employees or onsite contractors (usually through the Internet).
- Per Processor
The Per Processor model includes only server licenses. Each license is valid for a single processor, so server applications that run on multiple processors on a single server computer require multiple licenses. Products on the TechSoup site that are licensed per-processor include the words "Processor License" in the product name.
Some server products can be licensed in either the Server/CAL or Per Processor models. You can determine which licensing model TechSoup products use by examining the server product name and by checking whether TechSoup offers CALs for that server.
- Management Servers
- The Management Servers model includes server licenses, server management licenses (MLs) for the servers that are being managed, and client MLs for the nonserver operating system environments that are being managed.
Licensing Operating System Environments
Server operating systems and server applications can run in either physical or virtual operating system environments (OSEs). When your servers or other devices have multiple OSEs, you should check the OSE licensing requirements carefully.
For example, many Microsoft server licenses can be used for only a single operating system environment. When this is the case, if the server operating system or application is installed in more than one environment on a single server computer, a separate license is required for each environment. However, other Microsoft server licenses can be used in both the physical operating system environment and in one or more virtual environments.
Licensing Per-Processor Applications on Servers with Multiple Processors
If your server hardware has more than one processor, you need a separate processor license for each processor used (recognized) by the server operating system. In a physical operating system environment, you need as many processor licenses as the hardware has processors.
To run instances of the server software in virtual OSEs on a server, you need a software license for each virtual processor that each of those virtual OSEs uses. If a virtual OSE uses a fraction of a virtual processor, the fraction counts as a full virtual processor.
A virtual processor is a processor in a virtual (or otherwise emulated) hardware system. Virtual OSEs use virtual processors. Solely for licensing purposes, a virtual processor is considered to have the same number of threads and cores as each physical processor on the underlying physical hardware system. For details, consult the current PUR document.
Additional Server Information
TechSoup Articles
- A Field Guide to Servers
- Networks 101: An Introduction to Server Applications
- Virtualization 101
- Making Sense of Software Licensing