scope:

This part of ISO/IEC 10021 defines the overall system and service of an MHS and serves as a general overview of MHS.

Other aspects of Message Handling Systems and Services are defined in other parts of ISO/IEC 10021. The layout of ISO/IEC 10021 defining the Message Handling System and Services is shown in Table 1.

The technical aspects of MHS are defined in other parts of ISO/IEC 10021. The overall system architecture of MHS is defined in ISO/IEC 10021-2.

Purpose

This part of ISO/EC 10021 is one of a number of parts of ISO/EC 10021 and describes the system model and Elements of Service of the Message Handling System (MHS) and Services. This part of ISO/IEC 10021 overviews the capabilities of an MHS that are used for the provision of MH Services to enable users to exchange messages on a store-and-forward basis.

The Message Handling System is designed in accordance with the principles of the Reference Model of Open Systems Interconnection(OS1 Reference Model) (IS0 7498) and uses the Presentation Layer Services and Services offered by other, more general, Application Service Elements. An MHS can be constructed using any network fitting in the scope of OSI. The Message Transfer Service provided by the MTS is application independent. An example of a standardized application is the IPM Service. End systems can use the MT Service for specific applications that are defined bilaterally.

Elements of Service are the service features provided through the Application Processes. The Elements of Service are considered to be components of the services provided to users and are either elements of a basic service or they are optional user facilities, classified either as essential optional user facilities, or as additional optional user facilities