It is therefore the DSAs which access and maintain the directory database. Each DSA maintains a separate part of the directory, which can reside on a different computer system and can be located anywhere on the network. Obviously, it is impossible for the whole directory to have only one DSA, in which case the directory is completely centralised. More often, the directory will be distributed and composed of a collection of DSA's, supplied by different vendors and running on remote systems. Read on for more information on the DSA.
The DUA requests services from the DSA on behalf of the directory user. Within the distributed model, the DUA need not be on the same computer system as the attached DSA - the DUA can access the DSA remotely. Multiple DUA's (remote or local) can be connected to a single DSA. Read on for more information on the DUA.
The Directory user can be: