Users and applications would have to know which servers have the information in order to locate the resource. More Than Just Names Even though the naming and locating of network resources is a directory service's primary function, the database can store other information about the network configuration and resources. Because each resource has an object, and each object has attributes, the directory service can store any information about the resource that the network applications or the network users would find useful. For example, User objects can store cell phone numbers, photographs, salary information, employee ID, and home addresses. Information held by an object's attribute can also be made secure so that restricted information can only be viewed by objects and users that have the correct security.
Applications can also modify the schema for their specific needs.
In short, a directory service unifies all the network resources. A directory service enables users, administrators, and applications to think in terms of the entire network instead of the individual servers. In other words, instead of having to log in to several different servers and having to know which servers hold the printers, or which servers contain your authentication information, you simply log in to the network and use the printers on the network. The servers that are servicing the printers or holding your authentication information are transparent to you. In fact, because a directory service can be implemented as a distributed database, multiple servers could have the network information, providing fault tolerance, redundancy, and reducing network traffic.