The Active Directory catalog service provide Windows system administrators with ability to manage the complete set of users on the network. This powerful tool facilitates the work of network administrators with hundreds or even thousands of users and computers
Active Directory uses the application layer protocol LDAP (Lightweight Directory Access Protocol), which is used in directory services, i.e. hierarchical databases with any number of objects.
A database can contain information about users, user groups, computers, network resources, printers, applications, databases, and other objects.
Due to the fact that all these elements are in one group (domain), you can effectively manage all objects, give users and groups certain access, rules and permissions, or configure the computers they work on.
AD is perfect for smaller as well as large organizations, where a large number of users and computers can be divided into certain domains and managed effectively.