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 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