Microsoft Server CAL (Client Access License)
In order to use Microsoft server systems, you need so-called access licenses or server CALs (Client Access Licenses). These allow access to all servers in the corporate network that are interconnected. A CAL can be assigned to either a device or a user. Therefore, two types of access licenses are distinguished. Each user and device needs its own server CAL.
Device CALs are each assigned to a fixed device and allow to get it connected to the server. This device allows any number of users to access the server without being self-licensed. This form of server CALs is particularly suitable for enterprises in which several employees share a device and thus not every user needs their own access.
User CALs are assigned exactly to one user, who can then access the server from as many devices as required. This makes possible to work flexibly with desktop PC, laptop, tablet and other devices. An employee does not necessarily have to sit in his permanent workplace to be productive. This model is therefore suitable for enterprises in which several devices are used per employee.
Instructions for licensing
Users and device CALs can be mixed in the network, but cannot be split. They are always tied to their respective purpose. Some advanced services, such as Remote Desktop Services and Rights Management Services, require additional client licenses that are added to Windows Server Client Access licenses.
The access licenses are always version-bound. This means that the version of the access license must be the same as the server version used. However, the server CALs are partially down-compliant and can also be used with previous versions. Not applying to licensing the server variant, e.g. Standard, Datacenter or Enterprise.