1 Scope

This Recommendation | International Standard defines the abstract-service provided by the MTS (the MTS Abstract Service), and specifies the procedures to be performed by MTAs to ensure the correct distributed operation of the MTS. ITU-T Rec. X.402 | ISO/IEC 10021-2 identifies the other Recommendations | International Standards which define other aspects of Message Handling Systems.

Access to the MTS Abstract Service defined in this Recommendation | International Standard may be provided by the MTS Access Protocol (P3) defined in ITU-T Rec. X.419 | ISO/IEC 10021-6. The distributed operation of the MTS defined in this Recommendation | International Standard may be provided by the use of the MTS Transfer Protocol (P1) also defined in ITU-T Rec. X.419 | ISO/IEC 10021-6. The means by which messages may be routed through the MTS is specified in ISO/IEC 10021-10.

Section two of this Recommendation | International Standard defines the MTS Abstract Service. Clause 6 describes the Message Transfer System Model. Clause 7 provides an overview of the MTS Abstract Service. Clause 8 defines the semantics of the parameters of the MTS Abstract Service. Clause 9 defines the abstract-syntax of the MTS Abstract Service.

Section three of this Recommendation | International Standard defines the MTA Abstract Service. Clause 10 refines the model of the MTS, first presented in clause 6, to show that the MTS comprises a number of MTAs that interwork with one another to provide the MTS Abstract Service. Clause 11 provides an overview of the MTA Abstract Service. Clause 12 defines the semantics of the parameters of the MTA Abstract Service. Clause 13 defines the abstract-syntax of the MTA Abstract Service.

Section four of this Recommendation | International Standard specifies the procedures performed by MTAs to ensure the correct distributed operation of the MTS.

Annex A provides a reference definition of the MTS object identifiers cited in the ASN.1 modules in the body of this Recommendation | International Standard.

Annex B provides a reference definition of the upper bounds of the size constraints imposed upon variable length data types defined in ASN.1 modules in ITU-T Rec. X.411.

Annex C identifies the technical differences between the ISO/IEC and ITU-T versions of ITU-T Rec. X.411 and ISO/IEC 10021-4.

Annex D provides an index to this Recommendation | International Standard, categorised into: definitions of the MTS parameters; Abbreviations; Terms; ASN.1 modules; ASN.1 information object classes; ASN.1 types; and ASN.1 values.