When RDS CALs are required
Remote Desktop Services, formerly known as Terminal Services, allow users to log on to a central server and use applications or a complete desktop there. As soon as this feature is used, Microsoft requires a dedicated license: the RDS CAL.
The order of the licenses is important. An RDS CAL does not replace the regular Server CAL; it is added to it. A user who accesses a server via Remote Desktop Services therefore needs three building blocks: the server license on the hardware, the regular CAL for server access, and the RDS CAL for Remote Desktop usage.
Sizing RDS CALs correctly
- RDS CAL per user or per device. As with the regular CALs, there is a user-based and a device-based variant. The choice follows the same cost-effectiveness logic.
- In addition to the Server CAL. The RDS CAL is always a supplement, never a replacement for the regular Server CAL.
- Number of active RDS users. What matters is how many users or devices actually access via Remote Desktop Services.
- Pack sizes. RDS CALs are available in tiered pack sizes, from small to larger user counts.