ISO/IEC 10021-10:1998

Information technology — Message Handling Systems (MHS) — Part 10: MHS routing

Technologies de l'information — Systèmes de messagerie (MHS) — Partie 10: Routage MHS

General Information

• Status: Withdrawn
• Publication Date: 02-Sep-1998
• Withdrawal Date: 02-Sep-1998
• ICS: 35.240.20 - IT applications in office work
• Technical Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Drafting Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 16-Nov-2000

Relations

• Revised: ISO/IEC 10021-10:1999 - Information technology — Message Handling Systems (MHS): MHS routing — Part 10:
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 10021-10
First edition
1998-09-01
Information technology — Message
Handling Systems (MHS) —
Part 10:
MHS routing
Technologies de l'information — Systèmes de messagerie (MHS) —
Partie 10: Routage MHS
Reference number
B C
ISO/IEC 10021-10:1998(E)

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ISO/IEC 10021-10:1998 (E)
Contents
1 Scope . 1
2 Normative references. 1
2.1 Presentation references. 1
2.2 Directory references . 1
2.3 Message Handling references. 1
2.4 Country Code references. 2
2.5 Additional references . 2
3 Definitions. 2
3.1 MHS-routing definitions . 2
3.2 MHS definitions . 2
3.3 Directory definitions . 3
4 Abbreviations . 3
5 Conventions . 3
5.1 Conventions for routing model specification . 3
5.2 General font conventions . 3
5.3 Font conventions for ASN.1 definitions. 4
5.4 Rules for ASN.1 definitions . 4
6 MHS-routing Overview. 4
6.1 Operational characteristics . 4
6.2 Components of the model . 5
6.2.1 Routing-collective. 5
6.2.2 Routing-MTA . 5
6.2.3 Connection-group . 6
6.2.4 OR-address-subtree. 7
6.2.5 Routing-advice. 9
6.2.6 Local use tables. 9
6.3 Routing decision overview. 9
6.4 Directory organization. 10
6.5 Authentication principles . 10
7 Routing-collective-subtree. 11
7.1 Object classes . 11
7.1.1 Routing Collective object class. 11
7.1.2 Routing MTA object class . 11
7.1.3 Connection Group object class . 11
7.1.4 MTA Information object class. 12
7.2 Attribute types. 12
7.2.1 Routing Collective attribute types. 12
7.2.2 Routing MTA attribute types. 14
7.2.3 Connection Group attribute types . 14
7.2.4 MTA Information attribute types. 16
7.3 Name forms. 17
©  ISO/IEC 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or
utilized in any form or by any means, electronic or mechanical, including photocopying and micro-
film, without permission in writing from the publisher.
ISO/IEC Copyright Office • Case postale 56 • CH-1211 Genève 20 • Switzerland
Printed in Switzerland
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© ISO/IEC ISO/IEC 10021-10:1998 (E)
8 OR-address-subtree.17
8.1 OR-address Element object class.17
8.2 OR-address Element attribute types.17
8.2.1 Routing Advice .18
8.2.2 Expression Matches.19
8.2.3 Next Level Complete.20
8.2.4 Recipient MD Assigned Alternate Recipient .20
8.3 OR-address Element subclasses.20
8.3.1 OR-address Subtree Base object class.20
8.3.2 Common OR-address object classes.20
8.3.3 Mnemonic OR-address object classes .21
8.3.4 Terminal OR-address object classes.21
8.3.5 Numeric OR-address object classes .22
8.3.6 Postal OR-address object classes.22
8.4 OR-address Element Names .22
8.4.1 Common OR-address Element Names.22
8.4.2 Mnemonic OR-address Element Names.23
8.4.3 Terminal OR-address Element Names .23
8.4.4 Numeric OR-address Element Names.24
8.4.5 Postal OR-address Element Names .24
8.5 Generation of OR-address-element attributes.24
8.6 OR-address-subtree name forms.24
9 Procedures.26
9.1 Routing-MTA procedures.26
9.1.1 Amendment to the Front-end procedure .27
9.1.2 Routing-decision procedure .27
9.1.3 OR-address-subtree-read procedure .30
9.1.4 Local-delivery-evaluation procedure .32
9.1.5 Routing-knowledge-acquisition procedure .32
9.1.6 MTA-bind-in procedure .35
9.1.7 MTA-bind-out procedure .37
9.1.8 Trace verification step.39
9.2 Administrative procedures.39
9.2.1 Routing-MTA configuration .39
9.2.2 OR-address-subtree construction.40
10 Conformance.41
10.1 Routing-MTA conformance .41
10.2 Administrative DUA conformance.42
10.3 DSA conformance .42
Annex A Reference Definition of Object Identifiers.43
Annex B Reference Definition of MHS-routing Directory Objects.45
Annex C Reference Definition of MHS-routing OR-address-subtree.48
Annex D OR-address-subtree structure .55
Annex E MHS-routing example applications.60
Annex F Routing knowledge acquisition example.63
Annex G Profile and Connection-group Identifiers .64
Annex H Glossary of terms.66
Index .67
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ISO/IEC 10021-10:1998 (E) © ISO/IEC
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. 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.
International Standard ISO/IEC 10021-10 was prepared by Joint Technical Committee
ISO/IEC JTC 1, Information technology, Subcommittee SC 18, Document processing and
related communication
.
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 3: Abstract Service Definition Conventions
– 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
Annexes A to D form an integral part of this part of ISO/IEC 10021. Annexes E to H are for
information only.
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© ISO/IEC ISO/IEC 10021-10:1998 (E)
Introduction
This part of ISO/IEC 10021 is one of a number of parts of ISO/IEC 10021 defining Message
Handling in a distributed open systems environment.
Message Handling provides for the exchange of messages between users on a store-and-
forward basis. A message submitted by one user (the originator) is transferred through the
message-transfer-system (MTS) and delivered to one or more other users (the recipients).
This part of ISO/IEC 10021 defines a method for routing messages through the Message
Handling System (MHS).
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_________________________________________________________________________________________________
INTERNATIONAL STANDARD © ISO/IEC      ISO/IEC 10021-10:1998 (E)
_________________________________________________________________________________________________
Information technology –
Message Handling Systems (MHS) –
Part 10: MHS routing
1 Scope
This part of ISO/IEC 10021 specifies the means by which messages are routed through the MHS, and supplements the
procedures defined in 14.3 of ISO/IEC 10021-4.
Other parts of ISO/IEC 10021 define other aspects of the MHS. ITU-T Rec. F.400/X.400 | ISO/IEC 10021-1 defines the
user-oriented services provided by the MHS. ITU-T Rec. X.402 | ISO/IEC 10021-2 provides an architectural overview of
the MHS. ITU-T Rec. X.411 | ISO/IEC 10021-4 defines the abstract-service of the Message Transfer System.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of
ISO/IEC 10021. At the time of publication, the editions indicated were valid. All standards are subject to revision, and
parties to agreements based on this part of ISO/IEC 10021 are encouraged to investigate the possibility of applying the
most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid
International Standards.
2.1 Presentation references
This part of ISO/IEC 10021 cites the following Presentation specifications:
— ITU-T Recommendation X.680 (1994) | ISO/IEC 8824-1: 1995, Information technology - Abstract Syntax
Notation One (ASN.1): Specification of basic notation.
— ITU-T Recommendation X.681 (1994) | ISO/IEC 8824-2: 1995, Information technology - Abstract Syntax
Notation One (ASN.1): Information object specification.
2.2 Directory references
This part of ISO/IEC 10021 cites the following Directory specifications:
1)
— ITU-T Recommendation X.500 (1997) | ISO/IEC 9594-1: — , Information technology —Open Systems
Interconnection —The Directory: Overview of Concepts, Models, and Services.
1),
— ITU-T Recommendation X.501 (1997) | ISO/IEC 9594-2: — Information technology —Open Systems
Interconnection —The Directory: Models.
1)
— ITU-T Recommendation X.520 (1997) | ISO/IEC 9594-6: — , Information technology —Open Systems
Interconnection —The Directory: Selected attribute types.
1)
— ITU-T Recommendation X.521 (1997) | ISO/IEC 9594-7: — , Information technology —Open Systems
Interconnection —The Directory: Selected object classes.
2.3 Message Handling references
This part of ISO/IEC 10021 cites the following Message Handling System specifications:
— ITU-T Recommendation F.400/X.400 (1996), Message handling services: Message handling system and
service overview.
1)
ISO/IEC 10021-1: — , Information technology — Message Handling Systems (MHS) — Part 1: System and
service overview.

1)
 To be published
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ISO/IEC 10021-10:1998 (E) © ISO/IEC
— ITU-T Recommendation X.402 (1995) | ISO/IEC 10021-2: 1996, Information technology — Message
Handling Systems (MHS): Overall architecture.
— ITU-T Recommendation X.411 (1995) | ISO/IEC 10021-4: 1997, Information technology — Message
Handling Systems (MHS): Message transfer system: Abstract service definition and procedures.
2.4 Country Code references
This part of ISO/IEC 10021 cites the following Country Code specifications:
— ISO 3166-1: 1997, Codes for the representation of names of countries and their subdivisions — Part 1:
Country codes.
— CCITT Recommendation X.121 (1996), International number plan for public data networks.
2.5 Additional references
This part of ISO/IEC 10021 cites the following specification:
— ISO/IEC 9945-2: 1993, Information technology — Portable Operating System Interface (POSIX) — Part 2:
Shell and Utilities.
3 Definitions
For the purposes of this part of ISO/IEC 10021, the following definitions apply.
3.1 MHS-routing definitions
this part of ISO/IEC 10021
The following terms are defined in clauses 6 and 7 of :
— connection-group
— entry-connection-group
— enumerated connection-group
— indirect-exit-connection-group
— key-routing-collective
— local-exit-connection-group
— local-use-tables
— MHS-routing
— next-MTA
— OR-address-element
— OR-address-subtree
— routing-advice
— routing-collective
— routing-collective-subtree
— routing-MTA
— transit-exit-connection-group
— unenumerated connection-group
A glossary of these terms appears in Annex H.
3.2 MHS definitions
The following terms are defined in ITU-T Rec. X.402 | ISO/IEC 10021-2:
— Administration Management Domain (ADMD)
— Management Domain (MD)
— Message Handling System (MHS)
— Message Transfer Agent (MTA)
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© ISO/IEC ISO/IEC 10021-10:1998 (E)
— Message Transfer System (MTS)
— Originator/recipient Address (OR-address)
— Private Management Domain (PRMD)
— Reliable Transfer Service Element (RTSE)
For the purposes of this part of ISO/IEC 10021, the term message, where used unqualified, refers generically to a
message, probe, or report.
3.3 Directory definitions
The following terms are defined in ITU-T Rec. X.501 | ISO/IEC 9594-2:
— Directory Information Tree (DIT)
— Directory System Agent (DSA)
— Directory User Agent (DUA)
— Relative Distinguished Name (RDN)
4 Abbreviations
The abbreviations used in this part of ISO/IEC 10021 are defined in ITU-T Rec. X.402 | ISO/IEC 10021-2, and ITU-T
Rec. X.501 | ISO/IEC 9594-2 (see 3.2 and 3.3), except for the following.
— ACSE Association Control Service Element (ITU-T Rec. X.217 | ISO/IEC 8649)
— APS Asynchronous Protocol Specification (ITU-T Rec.X.445)
— IP Internet Protocol
— LAN Local Area Network
— PSAP Presentation Service Access Point (ISO/IEC 7498-3)
— WAN Wide Area Network
— X.25 A packet-switched network conforming to ITU-T Rec. X.25
5 Conventions
This part of ISO/IEC 10021 uses the descriptive conventions listed below.
5.1 Conventions for routing model specification
This part of ISO/IEC 10021 uses the following ASN.1-based descriptive conventions for the indicated purposes:
a) To define the data types and values for MHS-routing, ASN.1 itself.
b) To define the Directory entries for MHS-routing, the OBJECT-CLASS, ATTRIBUTE, NAME-FORM,
STRUCTURE-RULE, and MATCHING-RULE information object classes of ITU-T Rec. X.501 | ISO/IEC
9594-2.
Whenever this part of ISO/IEC 10021 describes a class of data structure having components, each component is
categorized as one of the following grades:
a) Mandatory (M): A mandatory component shall be present in every instance of the class.
b) Optional (O): An optional component may be present in an instance of the class at the discretion of the
object (e.g. user) supplying that instance.
c) (C): A conditional component shall be present in an instance of the class as specified by this
Conditional
part of ISO/IEC 10021.
5.2 General font conventions
Throughout this part of ISO/IEC 10021, terms are rendered in when defined. Terms that are proper nouns are
bold
capitalized, generic terms are not. Multi-word generic terms are hyphenated. Italic font is used for ASN.1 identifiers
defined in other International Standards.
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ISO/IEC 10021-10:1998 (E) © ISO/IEC
5.3 Font conventions for ASN.1 definitions
Throughout this part of ISO/IEC 10021, ASN.1 definitions appear in fixed-pitch font (of this Type) to highlight the
difference between normal text and ASN.1 definitions. The font used for ASN.1 definitions is smaller than that used for
normal text.
5.4 Rules for ASN.1 definitions
ASN.1 definitions appear both in the body of this part of ISO/IEC 10021 to aid the exposition, and again, formally, in
annexes for reference. If a difference is found between the ASN.1 used in the exposition and that formally defined in the
corresponding annex, a specification error is indicated.
6 MHS-routing Overview
The purpose of a Message Handling System (MHS) is to enable users to exchange messages on a store-and-forward basis.
A message submitted on behalf of one user, the originator, is conveyed by the Message Transfer System (MTS) and
subsequently delivered to the agents of one or more additional users, the recipients. The MTS comprises a collection of
Message Transfer Agents (MTAs), which are highly distributed, and a message may traverse a number of MTAs on the
journey from its originator to its recipient.
In MHS, the originator does not specify a path through the MTS to reach a recipient, but simply specifies a recipient OR-
name (from which the OR-address is obtained). It is the responsibility of each MTA to determine the next MTA to which
the message should be transferred to progress its journey to its recipient. Routing is thus the process of selecting, given an
OR-address, the MTA to which the message should next be transferred.
The other parts of ISO/IEC 10021 specify the services provided by MHS, and the protocols used to transfer messages
within the MTS. The means by which an MTA determines an appropriate route that will convey a message to its recipient
is the subject of this part of ISO/IEC 10021. The various mechanisms defined herein which enable MTAs to make this
determination constitute MHS-routing.
The path taken between an originator and recipient may vary on different occasions, since there will in general be a
number of possible paths between them, and factors such as congestion and availability may influence route selection.
MTAs acquire routing information by accessing Directory entries whose maintenance is the responsibility of an MHS
administrator. These entries model the various properties of the MHS that are relevant to routing. However, MHS-routing
does not depend on the provision of a fully interconnected Directory.
6.1 Operational characteristics
MHS-routing has the following operational characteristics:
a) In MHS-routing, the OR-address name-space is decoupled from the constraints of hardware organization
(e.g. the assignment of users to particular machines, or the ability of groups of machines to interconnect).
This is in contrast with routing strategies that use OR-address pattern-matching methods to make routing
decisions, which constrain an MHS administrator’s choice in the allocation of OR-addresses to users, and
require users to change their OR-addresses whenever their MTA changes.
OR-addresses are intended to reflect the organizational hierarchy, and to use only as many levels of OR-
address element as is required to achieve this. However, many organizations have staff distributed over
multiple locations (where staff will necessarily use a local MTA), or have multiple messaging systems in use
(e.g. mainframe-based, integrated office automation systems, and PC LAN email systems) where staff in any
one department are arbitrarily allocated to different systems. Separating the OR-address hierarchy from the
physical topology allows for the assignment to users of addresses which are compact and related to their
organizational role, regardless of their physical location.
b) MHS-routing supports the range of connection densities possible among MTAs. One extreme is where all
MTAs are connected to a common network and any MTA can connect to any other (e.g. a public wide-area
network). At the other extreme an administrator specifies precisely which MTA pairs are able to
communicate, as if the MTAs were connected by individual cables, regardless of the actual connection
method.
Some MHS installations restrict the topology (e.g. by performing all routing through a central switch MTA),
because of the
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