This example was drawn on the base of the Figure 2 illustrating the "Active Directory FAQ" from the website "Information Management Systems & Services" (IMSS) of the California Institute of Technology (Caltech) campus. [imss.caltech.edu/node/412]
"By using the Active Directory® Domain Services (AD DS) server role, you can create a scalable, secure, and manageable infrastructure for user and resource management, and you can provide support for directory-enabled applications, such as Microsoft® Exchange Server. ...
AD DS provides a distributed database that stores and manages information about network resources and application-specific data from directory-enabled applications. Administrators can use AD DS to organize elements of a network, such as users, computers, and other devices, into a hierarchical containment structure. The hierarchical containment structure includes the Active Directory forest, domains in the forest, and organizational units (OUs) in each domain. A server that is running AD DS is called a domain controller." [technet.microsoft.com/en-us/library/9a5cba91-7153-4265-adda-c70df2321982]
The Active Directory Domain Services diagram example was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Active Directory Diagrams solution from the Computer and Networks area of ConceptDraw Solution Park.