There's also the License "Mode" which moire directly affects the multiple server issue.

(Warning. I am not a MCLE (Microsoft Certified License Engineer). Please consult with one before entering into any purchase agreements).

From [link|http://www.microsoft.com/windowsserver2003/howtobuy/licensing/caloverview.mspx|http://www.microsoft.../caloverview.mspx] :

Client Access Licensing Modes
After you have selected a license type\ufffdWindows 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:

\ufffd 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.

\ufffd The number of Windows CALs required equals the number of users or devices accessing the server software.

\ufffd 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:

\ufffd 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.)

\ufffd The number of Windows CALs required equals the maximum number of users or devices that may simultaneously access or use the server software installed on a particular server. The Windows CALs you acquire are designated for use exclusively with a particular server.

\ufffd If you choose this licensing mode, you have a one-time right to switch to the other licensing mode\ufffdPer 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.