Do you remember the good old time of printed phone books? At that time, in larger German post offices you found a complete collection of all phone books of the whole republic put together at one point. To find a specific person you had to open the book containing all the entries of the town or village where the person lived and then to look for the name in the alphabetic-ordered list.
This is the idea of directory services. Information about people or (in general) objects is stored at a single place, grouped by organizational units, and easy to find by searching and reading the corresponding database.
Especially, directory services can be used to manage users, but also to manage computers, printers or other objects. Within an Microsoft Windows network, the Active Directory is the preferred solution to manage users and computers.
UNIX/Linux systems can take benefit from Active Directory too, but often OpenLDAP is an interesting alternative since it is more flexible and free of charge. Each of the two systems is useful to build up a central user management.
In case of interest please do not hesitate to contact us since we have a lot of experience which may help to build up or improve your directory services.