As directories have become global, companies have realized the need for directories which streamline network administration. Such directories need to be
Out of this need, the International Organization for Standardization (ISO) and the International Telecommunication Union (ITU) developed the X.500 standard.
X.500 specifies a naming and addressing structure, which functions at a global level because it is hierarchal and forms a logical tree. Each branch of the tree can represent a country or organization. eDirectory conforms to this structure as well as to the other requirements for the database, such as distinguished names, aliases, and the definitions for the types of entries and attributes that the database can contain. These definitions are called the directory schema, and X.500 allows for extensions to the schema definitions. eDirectory and eDirectory applications have added numerous object class and attribute definitions.
eDirectory differs from X.500 in that X.500 did not define any specific characters as separators for the components of a distinguished name, and eDirectory uses either a period or a slash for such a separator.
X.500 supports extensive query techniques that go far beyond standard name-to-address mapping functions. Since eDirectory was designed to be more than a name-to-address service, eDirectory supports these query techniques that return subsets of information about an entry. For example, eDirectory returns (1) the entry with all its attributes and values, (2) the entry with selected attributes and values, (3) the entry with all attributes and no values, and (4) the entry with selected attributes and no values.
Although in 1988 X.500 specified that the directory should be replicated and distributed, it did not specify a framework. In 1993, when X.500 specified protocols to use in synchronizing information between replicas, the first version of eDirectory was on the market. eDirectory uses the basic process of master/shadow, but it does not used the protocols defined in 1993. With the rise in popularity of LDAP (Lightweight Directory Access Protocol), standards bodies are concentrating on defining replication and synchronization extensions for LDAP. Novell is actively participating in these groups to help define these extensions so that they are compatible with eDirectory and other directories.
Access control either grants or denies access to a particular entry or attribute of an entry based on the requester's identity. A specification for access control did not appear until 1993 in X.500. Since the first version of eDirectory was already on the market at that time, Novell has continued to work with the standards bodies to define the framework for managing access control information.