Windows Server 2016 Client Access Licenses (CALs) are access rights that allow users or devices to access the services and features of Windows Server 2016. Companies need CALs to regulate server usage and ensure that only authorized users or devices have access to server resources. There are two types of CALs:

User CAL: This license is intended for individual users and allows them to access the server from any device. It is ideal for mobile employees or users who work from different locations and devices.

Device CAL: This license applies to individual devices that can be used by multiple users. It is particularly efficient for companies with shared workstations or a fixed workstation setup.

By using Windows Server 2016 CALs, companies can improve their network security, manage server access according to demand, and ensure compliance with licensing terms. The choice between User and Device CALs enables flexible adaptation to different work structures and user habits.