ISO/IEC 9594-7:2008 defines a number of object classes and name forms that may be found useful across a range of applications of the Directory. The definition of an object class involves listing a number of attribute types that are relevant to objects of that class. The definition of a name form involves naming the object class to which it applies and listing the attributes to be used in forming names for objects of that class. These definitions are used by the administrative authority that is responsible for the management of the directory information.
Any administrative authority can define its own object classes or subclasses and name forms for any purpose.
Such definitions can optionally use the notation specified in ISO/IEC 9594-2. It is recommended that an object class defined in ISO/IEC 9594-7:2008, or a subclass derived from one, or a name form defined in ISO/IEC 9594-7:2008, be used in preference to the generation of a new one, whenever the semantics is appropriate for the application.
Administrative authorities may support some or all of the selected object classes and name forms, and may also add additional ones.
All administrative authorities shall support the object classes that the directory uses for its own purposes (the top, alias and DSA object classes).