The establishment in various countries of
telematic services and computer-based store-and-forward message services in
association with public data networks creates a need to produce standards to
facilitate international message exchange between subscribers to such
services.
The CCITT,
considering
(a) the need for Message Handling Systems;
(b) the need to transfer and store messages of different types;
(c) that Recommendation X.200 defines the Reference Model of Open Systems
Interconnection for CCITT applications;
(d) that Recommendations X.208, X.217, X.218, and X.219 provide the foundation
for CCITT applications;
(e) that the X.500-series Recommendations define Directory Systems;
(f) that Message Handling Systems are defined in a series of Recommendations:
X.400, X.402, X.403, X.407, X.408, X.411, X.413, and X.419;
(g) that Interpersonal Messaging is defined in Recommendations X.420 and T.330,
unanimously declares
(1) that the abstract models of a Message Handling System are defined in section
two;
(2) that the configurations of a Message Handling System are defined in section
three;
(3) that naming, addressing, and routing within Message Handling Systems are
defined in section four.
(4) that the use of the Directory by Message Handling Systems is defined in
section five.
(5) that the OSI realization of a Message Handling System is specified in
section six.
Table of Contents
Section One - Introduction
0. Introduction
1. Scope 1
2. References
2.1 Open Systems Interconnection
2.2 Directory Systems 3
2.3 Message Handling Systems
3. Definitions 4
3.1 Open Systems Interconnection
3.2 Directory Systems 6
3.3 Message Handling Systems
4. Abbreviations
5. Conventions
5.1 ASN.1
5.2 Grade
5.3 Terms
Section Two - Abstract Models
6. Overview 8
7. Functional Model
7.1 Primary Functional Objects
7.1.1 The Message Handling System
7.1.2 Users
7.1.3 Distribution Lists
7.2 Secondary Functional Objects
7.2.1 The Message Transfer System
7.2.2 User Agents
7.2.3 Message Stores
7.2.4 Access Units
7.3 Tertiary Functional Objects
7.3.1 Message Transfer Agents
7.4 Selected AU Types
7.4.1 Physical Delivery
7.4.2 Telematic
7.4.3 Telex
8. Information Model
8.1 Messages
8.2 Probes
8.3 Reports
9. Operational Model
9.1 Transmittal
9.2 Transmittal Roles
9.3 Transmittal Steps
9.3.1 Origination
9.3.2 Submission
9.3.3 Import
9.3.4 Transfer
9.3.5 Export
9.3.6 Delivery
9.3.7 Retrieva
9.3.8 Receipt
9.4 Transmittal Events
9.4.1 Splitting
9.4.2 Joining
9.4.3 Name Resolution
9.4.4 DL Expansion
9.4.5 Redirection
9.4.6 Conversion
9.4.7 Non-delivery
9.4.8 Non-affirmation
9.4.9 Affirmation
9.4.10 Routing
10. Security Model
10.1 Security Policies
10.2 Security Services
10.2.1 Origin Authentication Security Services
10.2.2 Secure Access Management Security Service
10.2.3 Data Confidentiality Security Services
10.2.4 Data Integrity Security Services
10.2.5 Non-Repudiation Security Services
10.2.6 Message Security Labelling Security Service
10.2.7 Security Management Services
10.3 Security Elements
10.3.1 Authentication Security Elements
10.3.2 Secure Access Management Security Elements
10.3.3 Data Confidentiality Security Elements
10.3.4 Data Integrity Security Elements
10.3.5 Non-repudiation Security Elements
10.3.6 Security Label Security Elements
10.3.7 Security Management Security Elements
10.3.8 Double Enveloping Technique
Section Three - Configurations
11. Overview 33
12. Functional Configurations
12.1 Regarding the Directory
12.2 Regarding the Message Store
13. Physical Configurations
13.1 Messaging Systems
13.1.1 Access Systems
13.1.2 Storage Systems
13.1.3 Access and Storage Systems
13.1.4 Transfer Systems
13.1.5 Access and Transfer Systems
13.1.6 Storage and Transfer Systems
13.1.7 Access, Storage, and Transfer Systems
13.2 Representative Configurations
13.2.1 Fully Centralized
13.2.2 Centralized Message Transfer and Storage
13.2.3 Centralized Message Transfer
13.2.4 Fully Distributed
14. Organizational Configurations
14.1 Management Domains
14.1.1 Administration Management Domains
14.1.2 Private Management Domains
14.2 Representative Configurations
14.2.1 Fully Centralized
14.2.2 Directly Connected
14.2.3 Indirectly Connected
15. The Global MHS
Section Four - Naming, Addressing, and Routing
16. Overview
17. Naming
17.1 Directory Names
17.2 O/R Names
18. Addressing
18.1 Attribute Lists
18.2 Character Sets
18.3 Standard Attributes
18.3.1 Administration-domain-name
18.3.2 Common-name
18.3.3 Country-name
18.3.4 Extension-postal-O/R-address-components
18.3.5 Extension-physical-delivery-address-components
18.3.6 Local-postal-attributes
18.3.7 Network-address
18.3.8 Numeric-user-identifier
18.3.9 Organization-name
18.3.10 Organizational-unit-names
18.3.11 Physical-delivery-service-name
18.3.12 Personal-name
18.3.13 Physical-delivery-country-name
18.3.14 Physical-delivery-office-name
18.3.15 Physical-delivery-office-number
18.3.16 Physical-delivery-organization-name
18.3.17 Physical-delivery-personal-name
18.3.18 Post-office-box-address
18.3.19 Postal-code
18.3.20 Poste-restante-address
18.3.21 Private-domain-name
18.3.22 Street-address
18.3.23 Terminal-identifier
18.3.24 Terminal-type
18.3.25 Unformatted-postal-address
18.3.26 Unique-postal-name
18.4 Attribute List Equivalence
18.5 O/R Address Forms
18.5.1 Mnemonic O/R Address
18.5.2 Numeric O/R Address
18.5.3 Postal O/R Address
18.5.4 Terminal O/R Address
18.6 Conditional Attributes
19. Routing
Section Five - Use of the Directory
20. Overview
21. Authentication
22. Name Resolution
23. DL Expansion
24. Capability Assessment
Section Six - OSI Realization
25. Overview
26. Application Service Elements
26.1 The ASE Concept
26.2 Symmetric and Asymmetric ASEs
26.3 Message Handling ASEs
26.3.1 Message Transfer
26.3.2 Message Submission
26.3.3 Message Delivery
26.3.4 Message Retrieval
26.3.5 Message Administration
26.4 Supporting ASEs
26.4.1 Remote Operations
26.4.2 Reliable Transfer
26.4.3 Association Control
27. Application Contexts
Annexes
A Directory Object Classes and Attributes
A.1 Object Classes
A.1.1 MHS Distribution List
A.1.2 MHS Message Store
A.1.3 MHS Message Transfer Agent
A.1.4 MHS Organizational User
A.1.5 MHS Residential User
A.1.6 MHS User Agent
A.2 Attributes
A.2.1 MHS Deliverable Content Length
A.2.2 MHS Deliverable Content Types
A.2.3 MHS Deliverable EITs
A.2.4 MHS DL Members
A.2.5 MHS DL Submit Permissions
A.2.6 MHS Message Store
A.2.7 MHS O/R Addresses
A.2.8 MHS Preferred Delivery Methods
A.2.9 MHS Supported Automatic Actions
A.2.10 MHS Supported Content Types
A.2.11 MHS Supported Optional Attributes
A.3 Attribute Syntaxes
A.3.1 MHS DL Submit Permission
A.3.2 MHS O/R Address
A.3.3 MHS O/R Name
B Reference Definition of Object Identifiers
C Reference Definition of Directory Object Classes and Attributes
D Security Threats
D.1 Masquerade
D.2 Message Sequencing
D.3 Modification of Information
D.4 Denial of Service
D.5 Repudiation
D.6 Leakage of Information
D.7 Other Threats
E Provision of Security Services in Recommendation X.411
F Differences Between CCITT Recommendation and ISO Standard
G Index
Section One - Introduction
0. Introduction
This Recommendation is one of a set of Recommendations for Message Handling. The
entire set provides a comprehensive blueprint for a Message Handling System (MHS)
realized by any number of cooperating open systems.
The purpose of an 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. Access units (AUs) link the MTS to communication
systems of other kinds (e.g., postal systems). A user is assisted in the preparation,
storage, and display of messages by a user agent (UA). Optionally, he is assisted in
the storage of messages by a message store (MS). The MTS comprises a number of message
transfer agents (MTAs) which collectively perform the store-and-forward message
transfer function.
This Recommendation specifies the overall architecture of the MHS and serves as a
technical introduction to it.
The text of this Recommendation is the subject of joint CCITT-ISO agreement. The
corresponding ISO specification is ISO 10021-2.
1. Scope
This Recommendation defines the overall architecture of the MHS and serves as a
technical introduction to it.
Other aspects of Message Handling are specified in other Recommendations. A non-technical overview of Message Handling is provided by Recommendation X.400. The
conformance testing of MHS components is described in Recommendation X.403. The
conventions used in the definition of the abstract services provided by MHS components are
defined in Recommendation X.407. The detailed rules by which the MTS converts the
contents of messages from one EIT to another are defined in Recommendation X.408. The
abstract service the MTS provides and the procedures that govern its distributed operation
are defined in Recommendation X.411. The abstract service the MS provides is defined
in Recommendation X.413. The application protocols that govern the interactions of
MHS components are specified in Recommendation X.419. The Interpersonal Messaging
System, an application of Message Handling, is defined in Recommendation X.420. Telematic
access to the Interpersonal Messaging System is specified in Recommendation T.330.
The CCITT Recommendations and ISO International Standards on Message Handling are
summarized in Table 1/X.402.
Table .T.:1/X.402 Specifications for Message Handling Systems
+-------+--------+-------------------------------------------+ | CCITT | ISO |
SUBJECT MATT R | +- Introduction -+--------------------------
------------------+ | X.400 | 8505-1 | Service and system overview | |
X.402 | 8505 2 | Overall architecture | +- Various Aspects ------
-------------------------------------+ | X.403 | - | Conformance testing
| | X.407 | 8883-2 | Abstract service definition conventions | |
X.408 | - | Encoded information type conversion rules | +- Abstract Services --------
---------------------------------+ | X.411 | 8883-1 | MTS Abstract Service definition
and | | procedures for distributed operation | | X.413 |
TBS-1 | MS Abstract Service definition | +- Protocols ----+---------------
-----------------------------+ | X.419 | 8505-2 | Protocol specifications
| +- Interpersonal Messaging System ---------------------------+ | X.420 | 9065
| Interpersonal Messaging System | | T.330 | - | Telematic access
t IPMS | +-------+--------+------------------------------------------
--+
The Directory, the principal means for disseminating communication-related
information among MHS components, is defined in the X.500-series Recommendations, as
summarized in Table 2/X.402.
Table .T.:2/X.402 Specifications for Directories
+-------+--------+--------------------------------------+ | CCITT | ISO | SUBJECT
MATTE | +- Model --------+-------------------------------------
--+ | X.2 0 | 7498 | OSI Reference Model | +-------+--------+------
---------------------------------+ | X.500 | 9594-1 | Overview
| | X.501 | 9594-2 | Models | | X.509 | 9594-8 |
Authentication framework | | X.511 | 9594-3 | Abstract service definition
| | X.518 | 9594-4 | Procedures for distributed operation | | X.519 | 9594-5
| Protocol specifications | | X.520 | 9594-6 | Selected attribute types
| | X.521 | 9594-7 | Selected object classes | +-------+------
---+--------------------------------------+
The architectural foundation for Message Handling is provided by still other
Recommendations. The OSI Reference Model is defined in Recommendation X.200. The notation
for specifying the data structures of abstract services and application protocols,
ASN.1, and the associated encoding rules are defined in Recommendations X.208 and X.209.
The means for establishing and releasing associations, the ACSE, is defined in
Recommendations X.217 and X.227. The means for reliably conveying APDUs over associations,
the RTSE, is defined in Recommendations X.218 and X.228. The means for making
requests of other open systems, the ROSE, is defined in Recommendations X.219 and X.229.
The CCITT Recommendations and ISO International Standards foundational to Message
Handling are summarized in Table 3/X.402.
Table .T.:3/X.402 Specifications for MHS Foundations
+-------+--------+--------------------------------------+ | CCITT | ISO | SUBJECT
MATTE | +- Model --------+-------------------------------------
--+ | X.200 | 74 8 | OSI Reference Model | +- ASN.1 --------+------
---------------------------------+ | X.208 | 8824 | Abstract syntax notation
| | X.209 | 8825 | Basic encoding rules | +- Association
Control ---------------------------------+ | X.217 | 8649 | Service definition
| | X.227 | 8650 | Protocol specification | +- Reliable
Transfer -----------------------------------+ | X.218 | 9066/1 | Service definition
| | X.228 | 9066/2 | Protocol specification | +- Remote
Operations -----------------------------------+ | X.219 | 9072/1 | Service definition
| | X.229 | 9072/2 | Protocol specification | +-------+---
------+--------------------------------------+
This Recommendation is structured as follows. Section one is this introduction.
Section two presents abstract models of Message Handling. Section three specifies how one
can configure the MHS to satisfy any of a variety of functional, physical, and
organizational requirements. Section four describes the naming and addressing of users and
distribution lists and the routing of information objects to them. Section five
describes the uses the MHS may make of the Directory. Section six describes how the MHS is
realized by means of OSI. Annexes provide important supplemental information.
No requirements for conformance to this Recommendation are imposed.
2. References
This Recommendation and others in the set cite the documents below.
2.1 Open Systems Interconnection
This Recommendation and others in the set cite the following OSI specifications:
X.200 Basic reference model.(see also ISO 7498).
X.208 Specification of abstract syntax notation one (ASN.1) (see also ISO 8824).
X.209 Specification of basic encoding rules for abstract syntax notation one
(ASN.1) (see also ISO 8825).
X.217 Association control: Service definition (see also ISO 8649).
X.218 Reliable transfer: Model and service definition (see also ISO 9066-1).
X.219 Remote operations: Model, notation and service definition (see also ISO 9072-1).
X.227 Association control: Protocol specification (see also ISO 8650).
X.228 Reliable transfer: Protocol specification (see also ISO 9066-2).
X.229 Remote operations: Protocol specification (see also ISO 9072-2).
2.2 Directory Systems
This Recommendation and others in the set cite the following Directory System
specifications: of concepts, models, and service.)
X.500 The directory Overview (see also ISO 9594-1).
X.501 The directory Models (see also ISO 9594-2).
X.509 The directory Authentication framework (see also ISO 9594-8).
X.511 The directory Abstract service definition (see also ISO 9594-3).
X.518 The directory Procedures for distributed operation (see also
ISO 9594-4).
X.519 The directory Protocol specifications (see also ISO 9495-5).
X.520 The directory Selected attribute types (see also ISO 9495-6).
X.521 The directory Selected object classes (see also ISO 9495-7).
2.3 Message Handling Systems
This Recommendation and others in the set cite the following Message Handling System
specifications:
T.330 Telematic access to IPMS.
X.400 Message handling: Service and system overview (see also ISO 10021-1).
X.403 Message handling systems: Conformance testing.
X.407 Message handling systems: Abstract service definition conventions (see
also ISO 10021-3).
X.408 Message handling systems: Encoded information type conversion rules.
X.411 Message handling systems: Message transfer system: Abstract service
definition and procedures (see also ISO 10021-4).
X.413 Message handling systems: Message store: Abstract service definition
(see also ISO 1002105).
X.419 Message handling systems: Protocol specifications (see also
ISO 10021-6).
X.420 Message handling systems: Interpersonal messaging system (see also
ISO 10021-7).
3. Definitions
For the purposes of this Recommendation and others in the set, the definitions below
apply.
3.1 Open Systems Interconnection
This Recommendation and others in the set use the following terms defined in
Recommendation X.200, as well as the names of the seven layers of the Reference Model:
a) abstract syntax;
b) application entity (.I.ab:AE;);
c) application process;
d) application protocol data unit (.I.ab:APDU;);
e) application service element (.I.ab:ASE;);
f) distributed information processing task;
g) layer;
h) open system;
i) Open Systems Interconnection (.I.ab:OSI;);
j) peer;
k) presentation context;
l) protocol;
m) Reference Model;
n) transfer syntax; and
o) user element (.I.ab:UE;).
This Recommendation and others in the set use the following terms defined in
Recommendations X.208 and X.209, as well as the names of ASN.1 data types and values:
a) Abstract Syntax Notation One (.I.ab:ASN.1;);
b) Basic Encoding Rules;
c) explicit;
d) export;
e) implicit;
f) import;
g) macro;
h) module;
i) tag;
j) type; and
k) value.
This Recommendation and others in the set use the following terms defined in
Recommendation X.217:
a) application association; association;
b) application context (.I.ab:AC;);
c) Association Control Service Element (.I.ab:ACSE;);
d) initiator; and
e) responder.
This Recommendation and others in the set use the following terms defined in
Recommendation X.218:
a) Reliable Transfer (.I.ab:RT;); and
b) Reliable Transfer Service Element (.I.ab:RTSE;).
This Recommendation and others in the set use the following terms defined in
Recommendation X.219:
a) argument;
b) asynchronous;
c) bind;
d) parameter;
e) remote error;
f) remote operation;
g) Remote Operations (.I.ab:RO;);
h) Remote Operations Service Element (.I.ab:ROSE;);
i) result;
j) synchronous; and
k) unbind.
3.2 Directory Systems
This Recommendation and others in the set use the following terms defined in the
X.500-series Recommendations:
a) attribute;
b) certificate;
c) certification authority;
d) certification path;
e) directory entry; entry;
f) directory system agent (.I.ab:DSA;);
g) Directory;
h) hash function;
i) name;
j) object class;
k) object;
l) simple authentication; and
m) strong authentication.
3.3 Message Handling Systems
For the purposes of this Recommendation and others in the set, the definitions
indexed in annex G apply.
4. Abbreviations
For the purposes of this Recommendation and others in the set, the abbreviations
indexed in annex G apply.
5. Conventions
This Recommendation uses the descriptive conventions identified below.
5.1 ASN.1
This Recommendation uses several ASN.1-based descriptive conventions in annexes A
and C to define the Message Handling-specific information the Directory may hold. In
particular, it uses the OBJECT-CLASS, ATTRIBUTE, and ATTRIBUTE-SYNTAX macros of
Recommendation X.501 to define Message Handling-specific object classes, attributes, and
attribute syntaxes.
ASN.1 appears both in annex A to aid the exposition, and again, largely redundantly,
in annex C for reference. If differences are found between the two, a specification
error is indicated.
Note that ASN.1 tags are implicit throughout the ASN.1 module that annex C defines;
the module is definitive in that respect.
5.2 Grade
Whenever this Recommendation describes a class of data structure (e.g., O/R
addresses) having components (e.g., attributes), each component is assigned one of the
following .I.gl:grade;s:
a) .I.gl:mandatory; (.I.ab:M;): A mandatory component shall be present in every
instance of the class.
b) .I.gl:optional; (.I.ab:O;): An optional component shall be present in an
instance of the class at the discretion of the object (e.g., user) supplying that instance.
There is no default value.
c) .I.gl:defaultable; (.I.ab:D;): A defaultable component shall be present in an
instance of the class at the discretion of the object (e.g., user) supplying that
instance. In its absence a default value, specified by this Recommendation, applies.
d) .I.gl:conditional; (.I.ab:C;): A conditional component shall be present in an
instance of the class as dictated by this Recommendation.
5.3 Terms
Throughout the remainder of this Recommendation, terms are rendered in bold when
defined, in italic when referenced prior to their definitions, without emphasis upon
other occasions.
Terms that are proper nouns are capitalized, generic terms are not.
