User cals are the more common licensing option.
Windows server cal user vs device.
Even though user cals are more expensive buying one cal will be much cheaper than buying four.
A client access license cal is not a type of software but rather a license that grants users or devices access to sql server software.
Cal suites simplify licensing and tracking by reducing the number of licenses that are necessary to access microsoft servers.
Each user or device accessing a licensed windows server requires a windows server cal or a windows server and a remote desktop services rds cal.
A cal gives users or devices the right to access and use services provided by a windows server.
The only time the device cal model makes sense is when you have a large number of employees using a limited number of computers.
When you use the per device model a temporary license is issued the first time a device connects to the rd session host.
With the user cal you purchase a cal for every user who accesses the server to use services such as file storage or printing regardless of the number of devices they use for that access.
You either need to buy four device cals to cover those four devices or you need to buy a single user cal to cover that user.
Sql cals are a requirement only for the sql license cal model meaning that if you purchase sql server licenses per core standard core enterprise core you will not need to purchase any additional licenses.
The second time that device connects as long as the license server is activated and there are available rds cals the license server issues a permanent rds per device cal.
Like other cals cal suites can be licensed on either a per user or per device basis.
However every user or device that access windows server needs a cal to be compliant.
A client access license cal suite is a single license that provides use rights that are equivalent to multiple licenses.