Global directory services, such as DNS (BIND) and GDS (X.500), grew out of the computer industry's need to reference objects in distributed networks across an entire enterprise and across the globe.
With networks, applications that once looked for explicit object addressing information could instead look in local databases for object location mappings. As networks became larger and object volume increased, these local databases became harder to manage and difficult to use. These objects needed global names: the same name always referred to the same object regardless of where the object resides or where it is used in the distributed system. Figure 7 shows a global name explained. Global directory services were developed to act as registries that assign a unique name to the enterprise and its objects and list these global names in a directory so applications can perform lookup or search functions.
Figure 7 Format of Global Names