license server discovery mode(A mode that is configured on the terminal server that determines which method to use to find ("discover") a Terminal Services license server in order to request Terminal Services client access licenses (TS CALs))
license server(A computer on which the RD Licensing role service is installed. A license server issues RDS CALs to users or devices that connect to a remote desktop server)
Remote Desktop license server(A computer on which the RD Licensing role service is installed. A license server issues RDS CALs to users or devices that connect to a remote desktop server)