scope:

This part of ISO/IEC 10021 defines the overall architecture of the MHS and serves as a technical introduction to it.

Other aspects of Message Handling are specified in other parts of ISO/IEC  10021. A non-technical overview of Message Handling is provided by ISO/IEC  10021-1. The conventions used in the definition of the abstract services provided by MHS components are defined in ISO/IEC 10021-3. The abstract service the MTS provides and the procedures that govern its distributed operation are defined in ISO/IEC 10021-4. The abstract service the MS provides is defined in ISO/IEC 10021-5. The application protocols that govern the interactions of MHS components are specified in ISO/IEC 10021-6. The Interpersonal Messaging System, an application of Message Handling, is defined in ISO/IEC 10021-7.

The ISO International Standards and CCITT Recommendations on Message Handling are summarized in Table 1.

The Directory, the principal means for disseminating communication-related information among MHS components, is defined in ISO/IEC 9594, as summarized in Table 2.

The architectural foundation for Message Handling is provided by other International Standards. The OSI Reference Model is defined in ISO 7498. The notation for specifying the data structures of abstract services and application protocols, ASN.1, and the associated encoding rules are defined in ISO 8824 and 8825. The means for establishing and releasing associations, the ACSE, is defined in ISO 8649 and 8650. The means for reliably conveying APDUs over associations, the RTSE, is defined in ISO/IEC 9066. The means for making requests of other open systems, the ROSE, is defined in ISO/IEC 9072.

The ISO International Standards and CCITT Recommendations which form the foundation for Message Handling are summarized in Table 3.

This part of ISO/IEC 10021 is structured as follows. Section one gives a general overview. Section two presents abstract models of Message Handling. Section three specifies how one can configure the MHS to satisfy any of a variety of functional, physical, and organizational requirements. Section four describes the naming and addressing of users and distribution lists and the routing of information objects to them. Section five describes the uses the MHS may make of the Directory. Section six describes how the MHS is realized by means of OSI. Annexes provide important supplemental information.

No requirements for conformance to this part of ISO/IEC 10021 are imposed.