Microsoft offers flexible, cost-effective options for licensing the Windows Server 2008 family of products. Similar to Windows Server 2003 R2 licensing models, every running instance of the server software requires the purchase of a Windows Server license. In addition, a Windows Server 2008 Client Access License (CAL) is required for each user or device (or combination of both) that accesses or uses the Windows Server 2008 server software.
Client Access Licensing Requirements
Every user or device that accesses or uses the Windows Server 2008 server software requires the purchase of a Windows Server 2008 Client Access License (Windows Server CAL) except under the following circumstances:
If access to the instances of server software is only through the Internet without being authenticated or otherwise individually identified by the server software or through any other means
If access is to Windows Web Server 2008
If external users are accessing the instances of server software and you have acquired a Windows Server 2008 External Connector license for each server being accessed
For up to two devices or users to access your instances of the server software only to administer those instances
Device-based or User-based Windows Client Access Licenses
There are two types of Windows Client Access Licenses from which to choose: device-based or user-based, also known as Windows Device CALs or Windows User CALs. This means you can choose to acquire a Windows CAL for every device (used by any user) accessing your servers, or you can choose to acquire a Windows CAL for every named user accessing your servers (from any device).
The option to choose between the two types of Windows CALs offers you the flexibility to use the licensing that best suits the needs of your organization. For example:
Windows Device CALs might make most economic and administrative sense for an organization with multiple users for one device, such as shift workers.
Whereas, Windows User CALs might make most sense for an organization with many employees who need access to the corporate network from unknown devices (for example, when traveling) and/or an organization with employees who access the network from multiple devices.
Client Access Licensing Modes
After you have selected a license type—Windows Device CAL or Windows User CAL, you have the option to use the server software in two different modes: Per User/Per Device mode or Per Server mode. Both modes are available for either type of license.
Per User or Per Device Mode
Per User/Per Device mode is defined as follows:
A separate Windows CAL (of either type) is required for each user or device that accesses or uses the server software on any of your servers.
The number of Windows CALs required equals the number of users or devices accessing the server software.
If you choose this licensing mode, your choice is permanent. You can, however, reassign a Windows CAL from one device to another device or from one user to another user, provided the reassignment is made either (a) permanently away from the one device or user or (b) temporarily to accommodate the use of the Windows CAL either by a loaner device, while a permanent device is out of service, or by a temporary worker, while a regular employee is absent.
Per User/Per Device mode tends to be the most economical designation for Windows CALs in distributed computing environments where multiple servers within an organization provide services across most devices or users.
Note that Per User/Per Device mode replaces Per Seat mode, used in previous licensing models.
Per Server Mode
Per Server mode is defined as follows:
A separate Windows CAL (of either type) is required for each user or device that accesses or uses the server software on any of your servers. (This does not change the per server connection allowance of one CAL per one connection.)
The number of Windows CALs required equals the maximum number of users or devices that may simultaneously access or use the server software running on a particular server. The Windows CALs you acquire are designated for use exclusively with a particular server.
If you choose this licensing mode, you have a one-time right to switch to the other licensing mode—Per User/Per Device mode. Your Windows CALs (of either type) would then be used in Per User/Per Device mode instead.
Per Server mode tends to be the most economical designation for Windows CALs in computing environments where a small number of servers have limited access requirements.
