A directory service, also known as a name service, allows a client to obtain information about some named object. A familiar example is a telephone directory, which allows looking up a phone number given a person's name. In a DCE environment, the most important use of a directory service is to allow an RPC client to find a server that can respond to the client's request.
Other uses of a directory service are:
· Providing information about a host given a host name
· Providing information about a user given a user name
· Providing binding information for an RPC server given a server name
The purposes of a directory service in a distributed computing environment are:
· To allow objects to be identified by human-readable names. The directory service maps names to object attributes, such as network addresses.
· To provide location independence, which decouples the location of an object from the object itself. It allows applications, machines, services, and persons to easily access an object regardless of a change in location.