ISO/IEC 10746-2:2009
(Main)Information technology — Open distributed processing — Reference model: Foundations — Part 2:
Information technology — Open distributed processing — Reference model: Foundations — Part 2:
ISO/IEC 10746 provides a coordinating framework for the standardization of open distributed processing (ODP). This supports distribution, interworking, portability, and platform and technology independence. It establishes an enterprise architecture framework for the specification of ODP systems. ISO/IEC 10746 defines the essential concepts necessary to specify open distributed processing systems from five prescribed viewpoints. It provides a well-developed framework for the structuring of specifications for large-scale, distributed systems. The framework for system specification provided by ISO/IEC 10746 has four fundamental elements: an object modelling approach to system specification; the specification of a system in terms of separate but interrelated viewpoint specifications; the definition of a system infrastructure providing distribution transparencies for system applications; a framework for assessing system conformance. ISO/IEC 10746-2:2009 contains the definition of the concepts and analytical framework for normalized description of any distributed processing system. It introduces the principles of conformance to ODP standards and the way in which they are applied. These concepts and principles are used in ISO/IEC 10746-3 and to establish requirements for new ODP specification techniques.
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Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 10746-2
Second edition
2009-12-15
Information technology — Open
distributed processing — Reference
model: Foundations
Technologies de l'information — Traitement réparti ouvert — Modèle de
référence: Fondements
Reference number
ISO/IEC 10746-2:2009(E)
©
ISO/IEC 2009
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ISO/IEC 10746-2:2009(E)
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ISO/IEC 10746-2:2009(E)
CONTENTS
Page
iv
Foreword .
Introduction . v
1 Scope . 1
2 Normative references . 1
2.1 Identical Recommendations | International Standards. 1
3 Definitions. 1
3.1 Definitions from other Recommendations | International Standards. 1
3.2 Background definitions . 1
4 Abbreviations . 2
5 Categorization of concepts . 2
6 Basic interpretation concepts. 3
7 Basic linguistic concepts . 3
8 Basic modelling concepts. 4
9 Specification concepts. 6
9.1 Composition. 6
9.3 Decomposition . 6
10 Organizational concepts . 10
11 Properties of systems and objects. 11
11.1 Transparencies . 11
11.2 Policy concepts . 11
11.3 Temporal properties . 12
12 Naming concepts . 13
13 Concepts for behaviour. 13
13.1 Activity structure. 13
13.2 Contractual behaviour . 13
13.3 Service concepts. 15
13.4 Causality. 15
13.5 Establishing behaviours . 15
13.6 Dependability . 16
14 Management concepts . 16
15 ODP approach to conformance . 17
15.1 Conformance to ODP standards. 17
15.2 Testing and reference points . 17
15.3 Classes of reference points. 17
15.4 Change of configuration. 18
15.5 The conformance testing process . 18
15.6 The result of testing. 19
15.7 Relation between reference points . 19
© ISO/IEC 2009 – All rights reserved iii
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ISO/IEC 10746-2:2009(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 10746-2 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 7, Software and systems engineering, in collaboration with ITU-T. The identical text is
published as Rec. ITU-T X.902 (10/2009).
This second edition cancels and replaces the first edition (ISO/IEC 10746-2:1996), which has been technically
revised.
ISO/IEC 10746 consists of the following parts, under the general title Information technology — Open
distributed processing — Reference model:
⎯ Part 1: Overview
⎯ Part 2: Foundations
⎯ Part 3: Architecture
⎯ Part 4: Architectural semantics
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ISO/IEC 10746-2:2009(E)
Introduction
The rapid growth of distributed processing has led to a need for a coordinating framework for the standardization of
open distributed processing (ODP). This reference model of ODP provides such a framework. It creates an architecture
within which support of distribution, interworking, and portability can be integrated.
The reference model of open distributed processing (RM-ODP), Recommendations ITU-T X.901 | ISO/IEC 10746-1 to
X.904 | ISO/IEC 10746-4, is based on precise concepts derived from current distributed processing developments and,
as far as possible, on the use of formal description techniques for specification of the architecture.
The RM-ODP consists of:
– Recommendation ITU-T X.901 | ISO/IEC 10746-1: Overview: Contains a motivational overview of
ODP, giving scoping, justification and explanation of key concepts, and an outline of the ODP
architecture. It contains explanatory material on how the RM-ODP is to be interpreted and applied by its
users, who may include standards writers and architects of ODP systems. It also contains a categorization
of required areas of standardization expressed in terms of the reference points for conformance identified
in Rec. ITU-T X.903 | ISO/IEC 10746-3. This part is not normative.
– Recommendation ITU-T X.902 | ISO/IEC 10746-2: Foundations: Contains the definition of the concepts
and analytical framework for normalized description of (arbitrary) distributed processing systems. It
introduces the principles of conformance to ODP standards and the way in which they are applied. This
is only to a level of detail sufficient to support Rec. ITU-T X.903 | ISO/IEC 10746-3 and to establish
requirements for new specification techniques. This part is normative.
– Recommendation ITU-T X.903 | ISO/IEC 10746-3: Architecture: Contains the specification of the
required characteristics that qualify distributed processing as open. These are the constraints to which
ODP standards must conform. It uses the descriptive techniques from Rec. ITU-T X.902 | ISO/IEC
10746-2. This part is normative.
– Recommendation ITU-T X.904 | ISO/IEC 10746-4: Architectural semantics: Contains a formalization of
the ODP modelling concepts defined in this Recommendation | International Standard (clauses 8 and 9).
The formalization is achieved by interpreting each concept in terms of the constructs of the different
standardized formal description techniques. This part is normative.
This Recommendation | International Standard does not contain any annexes.
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ISO/IEC 10746-2:2009 (E)
INTERNATIONAL STANDARD
ITU-T RECOMMENDATION
Information technology – Open Distributed Processing –
Reference model: Foundations
1 Scope
This Recommendation | International Standard covers the concepts which are needed to perform the modelling of ODP
systems (see clauses 6 to 14), and the principles of conformance to ODP systems (see 15).
The concepts defined in clauses 6 to 14 are used in the reference model of open distributed processing to support the
definitions of:
a) the structure of the family of standards which are subject to the reference model;
b) the structure of distributed systems which claim compliance with the reference model (the configuration
of the systems);
c) the concepts needed to express the combined use of the various standards supported;
d) the basic concepts to be used in the specifications of the various components which make up the open
distributed system.
Clause 15 defines how the various standards supported constrain an implementation and how such an implementation
can be tested.
2 Normative references
The following Recommendations and International Standards contain provisions which, through reference in this text,
constitute provisions of this Recommendation | International Standard. At the time of publication, the editions indicated
were valid. All Recommendations and Standards are subject to revision, and parties to agreements based on this
Recommendation | International Standard are encouraged to investigate the possibility of applying the most recent
edition of the Recommendations and Standards listed below. Members of IEC and ISO maintain registers of currently
valid International Standards. The Telecommunication Standardization Bureau of the ITU maintains a list of currently
valid ITU-T Recommendations.
2.1 Identical Recommendations | International Standards
– Recommendation ITU-T X.903 (1995) | ISO/IEC 10746-3:1996, Information technology – Open
Distributed Processing – Reference Model: Architecture.
3 Definitions
For the purposes of this Recommendation | International Standard, the following definitions apply.
3.1 Definitions from other Recommendations | International Standards
There are no definitions from other Recommendations | International Standards in this Recommendation | International
Standard.
3.2 Background definitions
3.2.1 data: The representations of informationdealt with by information systems and users thereof.
3.2.2 distributed processing: Information processing in which discrete components may be located in different
places, and where communication between components may suffer delay or may fail.
3.2.3 ODP standards: This Reference Model and those standards that comply with it, directly or indirectly.
3.2.4 open distributed processing: Distributed processing designed to conform to ODP standards.
3.2.5 ODP system: A system (see 6.5) which conforms to the requirements of ODP standards.
Rec. ITU-T X.902 (10/2009) 1
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ISO/IEC 10746-2:2009 (E)
3.2.6 information: Any kind of knowledge that is exchangeable amongst users, about things, facts, concepts and so
on, in a universe of discourse.
Although information will necessarily have some forms of representation to make it communicable, it is the
interpretation of this representation (the meaning) that is relevant in the first place.
3.2.7 viewpoint (on a system): A form of abstraction achieved using a selected set of architectural concepts and
structuring rules, in order to focus on particular concerns within a system.
3.2.8 viewpoint correspondence: A statement that some terms or other linguistic constructs in a specification from
one viewpoint are associated with (e.g., describe the same entities as) terms or constructs in a specification from a
second viewpoint. The forms of association that can be expressed will depend on the specification technique used.
NOTE – The terms associated by a correspondence need not necessarily be expressed using a single specification technique. The
correspondence may associate a term in one specification technique with a term in some different specification technique. Rather
than linking every individual pair of terms, general correspondences can also be expressed between specification techniques
themselves. For example, composition operators defined in different specification techniques can be associated, implying
correspondences wherever these operators are used to link terms in the respective viewpoints.
4 Abbreviations
For the purposes of this Recommendation | International Standard, the following abbreviations apply:
ODP Open Distributed Processing
OSI Open Systems Interconnection
PICS Protocol Implementation Conformance Statement
PIXIT Protocol Implementation Extra Information for Testing
RM-ODP Reference Model of Open Distributed Processing
TP Transaction Processing
5 Categorization of concepts
The modelling concepts defined in this Recommendation | International Standard are categorized as follows:
a) Basic interpretation concepts: Concepts for the interpretation of the modelling constructs of any ODP
modelling language. These concepts are described in clause 6.
b) Basic linguistic concepts: Concepts related to languages; the grammar of any language for the
specification of the ODP architecture must be described in terms of these concepts. These concepts are
described in clause 7.
c) Basic modelling concepts: Concepts for building the ODP architecture; the modelling constructs of any
language must be based on these concepts. These concepts are described in clause 8.
d) Specification concepts: Concepts related to the requirements of the chosen specification languages used
in ODP. These concepts are not intrinsic to distribution and distributed systems, but they are
requirements to be considered in these specification languages. These concepts are described in clause 9.
e) Structuring concepts: Concepts that emerge from considering different issues in distribution and
distributed systems. They may or may not be directly supported by specification languages adequate for
dealing with the problem area. Specification of objects and functions that directly support these concepts
must be made possible by the use of the chosen specification languages. These concepts are described in
clauses 10 to 14.
f) Conformance concepts: Concepts necessary to explain the notions of conformance to ODP standards and
of conformance testing. These concepts are defined in clause 15.
Recommendation ITU-T X.903 | ISO/IEC 10746-3 uses the concepts in this Recommendation | International Standard
to specify the characteristics for distributed processing to be open. It is organized as a set of viewpoint languages. Each
viewpoint language refines concepts from the set defined in this Recommendation | International Standard. It is not
necessary for all viewpoint languages to adopt the same notations. Different notations may be chosen as appropriate to
reflect the requirements of the viewpoint. These notations may be natural, formal, textual or graphical. However, it will
be necessary to establish correspondences between the various languages to ensure overall consistency.
2 Rec. ITU-T X.902 (10/2009)
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ISO/IEC 10746-2:2009 (E)
6 Basic interpretation concepts
Although much of the ODP architecture is concerned with defining formal constructs, the semantics of the architectural
model and any modelling languages used have to be described. These concepts are primarily meta-concepts,
i.e., concepts which apply generally to any form of modelling activity. It is not intended that these concepts will be
formally defined, or that they be used as the basis of formal definition of other concepts.
Any modelling activity identifies:
a) elements of the universe of discourse;
b) one or more pertinent levels of abstraction.
The elements of the universe of discourse are entities and propositions.
6.1 entity: Any concrete or abstract thing of interest. While in general the word entity can be used to refer to
anything, in the context of modelling it is reserved to refer to things in the universe of discourse being modelled.
6.2 proposition: An observable fact or state of affairs involving one or more entities, of which it is possible to
assert or deny that it holds for those entities.
6.3 abstraction: The process of suppressing irrelevant detail to establish a simplified model, or the result of that
process.
6.4 atomicity: An entity is atomic at a given level of abstraction if it cannot be subdivided at that level of
abstraction.
Fixing a given level of abstraction may involve identifying which elements are atomic.
6.5 system: Something of interest as a whole or as comprised of parts. Therefore a system may be referred to as
an entity. A component of a system may itself be a system, in which case it may be called a subsystem.
NOTE – For modelling purposes, the concept of system is understood in its general, system-theoretic sense. The term "system"
can refer to an information processing system but can also be applied more generally.
6.6 architecture (of a system): A set of rules to define the structure of a system and the interrelationships
between its parts.
7 Basic linguistic concepts
Whatever the concepts or semantics of a modelling language for the ODP Architecture, the language will be expressed
in some syntax, which may include linear text or graphical conventions. It is assumed that any suitable language will
have a grammar defining the valid set of symbols and well-formed linguistic constructs of the language. The following
concepts provide a common framework for relating the syntax of any language used for the ODP architecture to the
interpretation concepts.
7.1 term: A linguistic construct which may be used to refer to an entity.
The reference may be to any kind of entity including a model of an entity or another linguistic construct.
7.2 sentence: A linguistic construct containing one or more terms and predicates; a sentence may be used to
express a proposition about the entities to which the terms refer.
A predicate in a sentence may be considered to refer to a relationship between the entities referred to by the terms it
links.
7.3 model: A system of postulates, value declarations and inference rules presented as a description of a state of
affairs (universe of discourse).
NOTE – Construction of a model allows precise description and reasoning about the state of affairs.
7.4 specification: A concrete representation of a model in some notation. Being in the real world, a specification
can be inspected, manipulated or communicated.
NOTE 1 – The specification may itself be an entity in the universe of discourse of the model it represents, but in simple cases it
will generally only be modelled in a separate universe of discourse addressing the system development process.
NOTE 2 – The specification can be instantiated by one or more implementations, particularly, for example, in the specification of
commodity software products. Each instantiation of the specification will, in general, represent a separate universe of discourse
and so lead to a separate set of entities with the relationships defined in the specification. Thus declaration of, for example, a
singleton object (such as the ODP system) in a specification will lead to a separate ODP system instance each time the
specification is implemented. This specification-instantiation distinction should be distinguished from the familiar type-instance
distinctions between terms within the specification.
Rec. ITU-T X.902 (10/2009) 3
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ISO/IEC 10746-2:2009 (E)
NOTE 3 – The relationship between a specification and its implementation underlies the conformance architecture defined in
clause 15.
7.5 notation: A means of concrete representation for a particular type of a model, expressed as a grammar and
suitable glyphs for its terminal symbols.
NOTE – One notation may be capable of representing a number of types of models, or of representing a specific viewpoint on a
more general model.
8 Basic modelling concepts
The detailed interpretation of the concepts defined in this clause will depend on the specification language concerned,
but these general statements of concept are made in a language-independent way to allow the statements in different
languages to be interrelated.
The basic concepts are concerned with existence and activity: the expression of what exists, where it is and what it does.
8.1 object: A model of an entity. An object is characterized by its behaviour (see 8.7) and, dually, by its state
(see 8.8). An object is distinct from any other object. An object is encapsulated, i.e., any change in its state can only
occur as a result of an internal action or as a result of an interaction (see 8.3) with its environment (see 8.2).
An object interacts with its environment at its interaction points (see 8.12).
Depending on the viewpoint, the emphasis may be placed on behaviour or on state. When the emphasis is placed on
behaviour, an object is informally said to perform functions and offer services (an object which makes a function
available is said to offer a service (see 13.3.1)). For modelling purposes, these functions and services are specified in
terms of the behaviour of the object and of its interfaces (see 8.5). An object can perform more than one function. A
function can be performed by the cooperation of several objects.
NOTE – The expression "use of a function" is a shorthand for the interaction with an object which performs the function.
8.2 environment (of an object): The part of the model which is not part of that object.
NOTE – In many specification languages, the environment can be considered to include at least one object which is able to
participate without constraint in all possible interactions (see 8.3), representing the process of observation.
8.3 action: Something which happens.
Every action of interest for modelling purposes is associated with at least one object.
The set of actions associated with an object is partitioned into internal actions and interactions. An internal action
always takes place without the participation of the environment of the object. An interaction takes place with the
participation of the environment of the object.
NOTE 1 – "Action" means "action occurrence" not "action type". That is to say, different actions within a specification may be of
the same type but still distinguishable in a series of observations. Depending on context, a specification may express that an
action has occurred, is occurring or may occur.
This usage of action occurrence needs to be seen in the light of the notes on specification in 7.4. Thus the specification of a
firework may require it to produce five flashes and a bang, which are six actions where flash and bang are action types. However,
each member of a box of fireworks conforming to this specification will produce its own copy of this behaviour.
NOTE 2 – The granularity of actions is a design choice. An action need not be instantaneous. Actions may overlap in time.
NOTE 3 – Interactions may be labelled in terms of cause and effect relationships between the participating objects. The concepts
that support this are discussed in 13.3.
NOTE 4 – An object may interact with itself, in which case it is considered to play at least two roles in the interaction.
NOTE 5 – Involvement of the environment represents observability. Thus, interactions are observable whereas internal actions
are not observable, because of object encapsulation. In most specification techniques observability is an implicit property of the
environment and, therefore, it is not necessary to model the observer explicitly; however, there may, in some circumstances, be a
need to include an explicit observer object in the specification, thereby increasing the cardinality of all interactions.
NOTE 6 – Observability of an action may depend on the level of specification. For instance, an action specification at one level
of abstraction or in one viewpoint may correspond to a specification of multiple concurrent actions at a different level of
abstraction or in another viewpoint. For example, a basic single function of a system in one viewpoint may be realized by
multiple concurrent actions in a different viewpoint, defining a grid computing or sensor network, each one executing at the same
time on network-connected computers in different locations. In this case, the observability of the occurrence of the basic single
action can be deduced from the observability of those other multiple concurrent actions.
8.4 event: The fact that an action has taken place. When an event occurs, the information about the action that has
taken place becomes part of the state of the system and may thus subsequently be communicated in other interaction
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