ISO/IEC 10021-4 (2003-12)

ISO/IEC 10021-4:2003 ITU-T Rec. X.411 defines the Message Transfer System (MTS) Abstract Service and the MTS Model, and provides an overview of the MTS Abstract Service. It defines both the semantics of the parameters of the MTS Abstract Service and the abstract-syntax of the MTS Abstract Service. ISO/IEC 10021-4:2003 ITU-T Rec. X.411 defines the Message Transfer Agent (MTA) Abstract Service and refines the model of the MTS to show that the MTS comprises a number of MTAs that interwork with one another to provide the MTS Abstract Service. An overview of the MTA Abstract Service is provided. ISO/IEC 10021-4:2003 ITU-T Rec. X.411 defines both the semantics of the parameters of the MTA Abstract Service and the abstract-syntax of the MTA Abstract Service. It specifies the procedures performed by MTAs to ensure the correct distributed operation of the MTS.