Server software that requires Client Access Licenses (CALs) offers one base CAL and may offer one or more additive CALs. Base CALs license access to server functionality. Additive CALs license access to advanced server functionality and must be licensed in addition to the corresponding base CAL. Both types of CALs are available for both users and devices.
This brief replaces a previous version published in April 2010.
Significant changes in this new version include:
Revised text and improved figures to illustrate CAL suite license options
Updated references to Lync Server (formerly Office Communications Server)
Base and Additive Client Access Licenses: An Explanation (PDF, 1.42 MB)
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