| ### Integration of the DCE Technology Components One of the benefits of OSF's DCE is its coherence: although the components themselves are modular with well-defined interfaces, they are also well integrated; the various DCE components each make use of the services of the other components wherever possible. For example, the RPC facility uses the directory service to advertise and look up RPC-based servers and their characteristics; it uses the security service to ensure message integrity and privacy; and it uses DCE Threads to handle concurrent execution of multiple RPCs. The Distributed File Service uses threads, RPC, directory service, distributed time service, and security service in providing its file service. In general, the DCE components shown higher in the DCE architecture (see the figure entitled DCE Architecture) make use of the components shown lower in the architecture. For example, DCE Threads is used by most other DCE components, but does not itself use other components. This ordering is not strictly hierarchical; often two services each depend on the other. For example, the directory service uses the security service, which in turn uses the directory service. The interdependence of DCE components is explained in more detail in Integration of DCE Technology Components. ###