Provides the directory capabilities required by OSI applications, OSI management processes, other OSI layer entities, and telecommunications services. Among the capabilities which it provides are those of "user-friendly naming", whereby objects can be referred to by names which are suitable for citing by human users (though not all objects need have user-friendly names); and "name-to-address mapping" which allows the binding between objects and their locations to be dynamic. The latter capability allows OSI networks, for example, to be "self-configuring" in the sense that addition, removal and the changes of object location do not affect OSI network operation.