Objects are categorized into OM classes based on their purpose and internal structure. An object is an instance of its OM class. An OM class is characterized by OM attribute types that may appear in its instances. An OM class is uniquely identified by an ASN.1 object identifier.
Later in this topic, it will be shown how OM classes are organized into groups of OM classes, called packages, that support some aspect of the directory service.
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OM Class Hierarchy and Inheritance Properties