Federated Naming Service (FNS) provides a method for federating multiple naming services under a single, simple interface for naming and directory operations. Naming services that can be linked with FNS include: NIS+, NIS, files, DNS, and X.500/LDAP.
The programming interface and policies that FNS supports are specified by XFN (X/Open Federated Naming).
FNS is useful for the following reasons:
A single uniform naming and directory interface is provided to clients for accessing naming and directory services. Consequently, the addition of new naming and directory services does not require changes to applications or existing services.
Names can be composed in a uniform way. FNS defines a way to uniformly compose names from different naming systems so that applications can uniformly address objects in these different naming systems.
Coherent naming is encouraged through the use of shared contexts and shared names. Different applications can use these shared names and contexts and need not duplicate the work.