Instead, these deployments follow a directory structure which at the top level mirrors that of the Domain Name System, as described by RFC 2247.
The elements of an organization represented in the directory (e.g., people, roles, or devices) in a DIT may be modeled by a variety of techniques.
The determining factors include: Early deployments of X.500 within corporations and institutions with entries representing the employees of those organizations often used a DIT structure which mirrored the organizational structure, with organizational unit entries corresponding to departments or divisions of the organization.
The disadvantage of this approach is that it when the organizational structure is changed, or if employees change their legal name, can require the moving or renaming of entries in the directory, which adds both complexity and overhead and can also upset applications not designed to deal gracefully with such moves.
These changes can be effected through just an attribute modification, and applications which may be using the DN as a unique identifier (e.g. in a database) do not need to be touched.