ISO/IEC 10021-1:2003

INTERNATIONAL ISO/IEC
STANDARD 10021-1
Second edition
2003-11-15


Information technology — Message
Handling Systems (MHS)
Part 1:
System and service overview
Technologies de l'information — Systèmes de messagerie (MHS)
Partie 1: Présentation générale du système et des services





Reference number
ISO/IEC 10021-1:2003(E)
©
ISO/IEC 2003

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ISO/IEC 10021-1:2003(E)
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ISO/IEC 10021-1:2003(E)
Contents Page
1 Scope . 1
2 Normative references. 1
3 Terms and definitions. 3
3.1 Open Systems Interconnection . 3
3.2 Directory Systems . 4
4 Abbreviations . 4
5 Conventions. 5
6 Purpose . 5
7 Functional Model of MHS. 5
7.1 Description of the MHS Model . 5
7.2 Structure of Messages. 6
7.3 Application of the MHS model . 7
7.3.1 Physical Mapping. 7
7.3.2 Organizational Mapping . 8
7.3.3 Administration Management Domain . 8
7.3.4 Private Management Domain . 8
7.4 The Message Store . 9
7.4.1 Physical Configurations . 12
7.4.2 Organizational Configurations. 12
8 The Message Transfer Service. 12
8.1 Submission and Delivery. 12
8.2 Transfer . 12
8.3 Notifications . 12
8.4 User Agent. 13
8.5 Message Store. 13
8.6 Access Unit . 13
8.7 Use of the MTS in the Provision of Various Services . 13
9 The IPM Service . 13
9.1 IPM Service Functional Model. 13
9.2 Structure of IP-messages. 13
9.3 IP-notifications. 14
10 Intercommunication with Physical Delivery Services . 15
10.1 Introduction . 15
10.2 Organizational Configurations. 16
11 Specialized Access. 16
11.1 Introduction . 16
11.2 Telex Access. 17
11.2.1 Registered Access to the IPM Service . 17
11.2.2 Non-registered (Public) Access to the IPM Service . 17
11.3 Facsimile Access. 17
11.3.1 Non-registered (Public) Access from the IPM Service . 17
12 Naming and Addressing . 17
12.1 Introduction . 17
12.2 Directory Names . 17
12.3 OR-Names . 18
12.4 OR-Addresses. 18
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ISO/IEC 10021-1:2003(E)
13 MHS Use of Directory.18
13.1 Introduction.18
13.2 Functional Model .19
13.3 Physical Configurations.19
14 Distribution Lists in MHS .20
14.1 Introduction.20
14.2 Properties of a DL .20
14.3 Submission .21
14.4 DL Use of a Directory .21
14.5 DL Expansion .21
14.6 Nesting.21
14.7 Recursion Control .21
14.8 Delivery .21
14.9 Routing Loop Control.21
14.10 Notifications.22
14.11 DL Handling Policy.22
15 Security Capabilities of MHS.22
15.1 Introduction.22
15.2 MHS Security Threats .22
15.2.1 Access Threats .22
15.2.2 Inter-Message Threats .22
15.2.3 Intra-Message Threats.23
15.2.4 Data Store Threats .23
15.3 Security Model.23
15.3.1 Secure Access Management and Administration .23
15.3.2 Secure Messaging .23
15.4 MHS Security Capabilities .24
15.5 Security Management .25
15.6 MHS Security Dependencies .26
15.7 IPM Security.26
16 Conversion in MHS.27
17 Clause 17 of the corresponding ITU-T Recommendation is not part of this International Standard.28
18 Elements of Service – Purpose .28
19 Elements of service – Classification .31
19.1 Purpose of Classification .31
19.2 Basic Message Transfer Service.32
19.3 MT Service Optional User Facilities.32
19.4 Base MH/PD Service Intercommunication .34
19.5 Optional User Facilities for MH/PD Service Intercommunication.34
19.6 Base Message Store .34
19.7 MS Optional User Facilities.35
19.8 Basic Interpersonal Messaging Service .35
19.9 IPM Service Optional User Facilities .36
Annex A (informative) Glossary of Terms .40
Annex B (informative) Definitions Of Elements Of Service .55
Annex C (informative) Elements of service changes from 1992 .80
Annex D (informative) Differences between ISO/IEC 10021-1 and ITU-T Recommendation X.400 .82

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ISO/IEC 10021-1:2003(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form
the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the
development of International Standards through technical committees established by the respective organization to deal
with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest.
Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International Standards
adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO
and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 10021-1 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee
SC 6, Telecommunications and information exchange between systems.
This part of ISO/IEC 10021 is technically aligned with ITU-T Recommendation F.400/X.400 (1999) but is not published
as identical text.
This second edition cancels and replaces the first edition (ISO/IEC 10021-1:1990), which has been technically revised. It
also incorporates Technical Corrigenda 1 to 7 and consolidates Amendment 1:1994.
ISO/IEC 10021 consists of the following parts, under the general title Information technology — Message Handling
Systems (MHS):
 Part 1: System and service overview
 Part 2: Overall architecture
 Part 4: Message transfer system — Abstract service definition and procedures
 Part 5: Message store: Abstract service definition
 Part 6: Protocol specifications
 Part 7: Interpersonal messaging system
 Part 8: Electronic Data Interchange Messaging Service
 Part 9: Electronic Data Interchange Messaging System
 Part 10: MHS routing
 Part 11: MHS Routing — Guide for messaging systems managers [Technical Report]
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ISO/IEC 10021-1:2003(E)
Introduction
This document is one of a set of Recommendations | International Standards for Message Handling. The entire set
provides a comprehensive specification for a Message Handling System (MHS) comprising any number of co-operating
open systems.
Message Handling Systems and Services enable users to exchange messages on a store-and-forward basis. A message
submitted by one user, the originator, is conveyed by the Message Transfer System (MTS), the principal component of a
larger Message Handling System (MHS), and is subsequently delivered to one or more additional users, the message's
recipients.
An MHS comprises a variety of interconnected functional entities. Message Transfer Agents (MTAs) co-operate to
perform the store-and-forward message transfer function. Message Stores (MSs) provide storage for messages and enable
their submission, retrieval and management. User Agents (UAs) help users access MHS. Access Units (AUs) provide
links to other communication systems and Services of various kinds (e.g., Telematic Services, Postal Services).
This part of ISO/IEC 10021 specifies the overall system and service description of Message Handling capabilities.

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INTERNATIONAL STANDARD ISO/IEC 10021-1:2003(E)

Information technology — Message Handling Systems (MHS) —
Part 1:
System and service overview
1 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 structure of
ISO/IEC 10021 (all parts) 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 10021-2:2003.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only
the edition cited applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
ISO/IEC 7498-1:1994, Information technology – Open Systems Interconnection – Basic Reference Model: The Basic
Model
ISO/IEC 8649:1996, Information technology – Open Systems Interconnection – Service definition for the Association
Control Service Element
ISO/IEC 8824-1:1998, Information technology – Abstract Syntax Notation One (ASN.1): Specification of basic notation
ISO/IEC 8825-1:1998, Information technology – ASN.1 encoding rules: Specification of Basic Encoding Rules (BER),
Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)
ISO/IEC 9066-1:1989, Information processing systems – Text communication – Reliable Transfer – Part 1: Model and
service definition
ISO/IEC 13712-1:1995, Information technology – Remote Operations: Concepts, model and notation
ISO/IEC 9594 (all parts), Information technology – Open Systems Interconnection – The Directory
ISO/IEC 10021-2:2003, Information technology – Message Handling Systems (MHS) – Part 2: Overall architecture
ISO/IEC 10021-4:2003, Information technology – Message Handling Systems (MHS) – Part 4: Message transfer system:
Abstract service definition and procedures
ISO/IEC 10021-5:1999, Information technology – Message Handling Systems (MHS) – Part 5: Message store: Abstract
service definition
ISO/IEC 10021-6:2003, Information technology – Message Handling Systems (MHS) – Part 6: Protocol specifications
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ISO/IEC 10021-1:2003(E)
ISO/IEC 10021-7:2003, Information technology – Message Handling Systems (MHS) – Part 7: Interpersonal messaging
system
ISO/IEC 10021-8:1999, Information technology – Message Handling Systems (MHS) – Part 8: Electronic Data
Interchange Messaging Service
ISO/IEC 10021-9:1999, Information technology – Message Handling Systems (MHS) – Part 9: Electronic Data
Interchange Messaging System
ISO/IEC 10021-10:1999, Information technology – Message Handling Systems (MHS) – Part 10: MHS routing
ISO/IEC 10021-11:1999, Information technology – Message Handling Systems (MHS) – Part 11: MHS Routing – Guide
for messaging systems managers
ISO/IEC 11588-1:1996, Information technology – Message Handling Systems (MHS) management – Part 1: Model and
architecture
ISO/IEC 11588-3:1997, Information technology – Message Handling Systems (MHS) management – Part 3: Logging
information.
ISO/IEC 11588-8:1997, Information technology – Message Handling Systems (MHS) management – Part 8: Message
Transfer Agent management.
CCITT Recommendation F.423:1992, Message handling services: Intercommunication between the interpersonal
messaging service and the telefax service
CCITT Recommendation F.440:1992, Message handling services: The voice messaging service
CCITT Recommendation T.330:1988, Telematic access to interpersonal messaging system
CCITT Recommendation X.408 (1988), Message handling systems: Encoded information type conversion rules
CCITT Recommendation X.440 (1992), Message handling systems: Voice messaging system
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ISO/IEC 10021-1:2003(E)
Table 1 – Structure of MHS Standards
Short title Joint MHS Joint support ITU-T only
ISO/IEC ITU-T ISO/IEC ITU-T System Service
MHS: System and service overview 10021-1 X.400  F.400
MHS: Overall architecture 10021-2 X.402
MHS: Encoded information type conversion rules
 X.408
MHS: MTS: Abstract service definition and 10021-4 X.411
procedures
MHS: MS: Abstract -service definition 10021-5 X.413
MHS: Protocol specifications 10021-6 X.419
MHS: Interpersonal messaging system 10021-7 X.420
Telematic Access to IPMS
MHS: EDI messaging service 10021-8 F.435 T.330
MHS: EDI messaging system 10021-9 X.435
MHS: Voice messaging service
MHS: Voice messaging system  F.440
MHS: Routing 10021-10 X.412 X.440
MHS: Routing: Guide for Messaging System 10021-11 X.404
Managers
MHS: Naming and addressing for public   F.401
MH services

MHS: The public message transfer service
F.410
MHS: Intercommunication with public physical
F.415
delivery services

MHS: The public IPM service
F.420
MHS: Intercommunication between IPM
F.421
service and Telex

MHS: Intercommunication between IPM service
F.423
and Telefax
OSI: Basic Reference Model  7498-1 X.200
OSI: Specification of Abstract Syntax Notation One 8824-1 X.680
(ASN.1)
OSI: Specification of Basic Encoding Rules for
8825-1 X.690
Abstract Syntax Notation One (ASN.1)
OSI: Association Control: Service Definition 8649 X.217
OSI: Association Control: Protocol Specification 8650-1 X.227
OSI: Reliable Transfer: Model and service definition 9066-1 X.218
OSI: Reliable Transfer: Protocol Specification 9066-2 X.228
OSI: Remote Operations: Concepts, Model & 13712-1 X.880
Notation
OSI: Remote Operations: Service Definition 13712-2 X.881
OSI: Remote Operations: Protocol Specification 13712-3 X.882

3 Terms and definitions
For the purposes of this document, the terms and definitions given in Annex A and the following apply.
3.1 Open Systems Interconnection
This part of ISO/IEC 10021 makes use of the following terms defined in ISO/IEC 7498-1:
a) Application Layer;
b) application-process;
c) Open Systems Interconnection;
d) OSI Reference Model.
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ISO/IEC 10021-1:2003(E)
3.2 Directory Systems
This part of ISO/IEC 10021 makes use of the following terms defined in ISO/IEC 9594-1:
a) directory entry;
b) directory system agent;
c) Directory System;
d) directory user agent.
This part of ISO/IEC 10021 makes use of the following terms defined in ISO/IEC 9594-2:
e) attribute;
f) group;
g) name.
4 Abbreviations
A Additional
ADMD Administration Management Domain
AU Access Unit
CA Contractual Agreement
DL Distribution List
DSA Directory System Agent
DUA Directory User Agent
E Essential
EDI Electronic Data Interchange
EIT Encoded Information Type
I/O Input/Output
IP Interpersonal
IPM Interpersonal Messaging
IPMS Interpersonal Messaging System
MD Management Domain
MH Message Handling
MHS Message Handling System
MS Message Store
MT Message Transfer
MTA Message Transfer Agent
MTS Message Transfer System
N/A Not applicable
OR Originator/Recipient
OSI Open Systems Interconnection
PD Physical Delivery
PDAU Physical Delivery Access Unit
PDS Physical Delivery System
PM Per-message
PR Per-recipient
PRMD Private Management Domain
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ISO/IEC 10021-1:2003(E)
PTLXAU Public Telex Access Unit
RPOA Recognized Private Operating Agency
TLMA Telematic Agent
TLXAU Telex Access Unit
UA User Agent
5 Conventions
In this Standard, the expression “Administration” is used to indicate a telecommunication Administration, a recognized
private operating agency, and, in the case of intercommunication with Public Delivery Service, a Postal Administration.
6 Purpose
This part of ISO/IEC 10021 is one of a set of Recommendations which 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 R
...