ITU-T X 641-1997 Information Technology - Quality of Service Framework - Series X Data Networks and Open System Communication - OSI Networking and System Aspects - Quality of Servi.pdf

1、I NTERNATIONAL TELECOMM U N CATION UN ION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU X.641 (I 2/97) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUN I CATI ON OS1 networking and system aspects - Quality of Service Information technology - Quality of Service: Framework ITU-T Recommendation X

2、.641 (Previously CCITT Recommendation) ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATION PUBLIC DATA NETWORKS Services and facilities In terfaces Transmission, signalling and switching Network aspects Maintenance Administrative arrangements OPEN SYSTEM INTERCONNECTION Model

3、and notation Service definitions Connection-mode protocol specifications Connectionless-mode protocol specifications PICS proformas Protocol Identification Security Protocols Layer Managed Objects Conformance testing INTERWORKING BETWEEN NETWORKS General Satellite data transmission systems MESSAGE H

4、ANDLING SYSTEMS DIRECTORY OS1 NETWORKING AND SYSTEM ASPECTS Networking X. 1-X. 19 X.20-X.49 X.50-X.89 X.90-X.149 X.150-X.179 X. 180-X. 199 X.200-X.209 X.2 1 O-X.2 19 X.220-X.229 X.230-X.239 X.240-X.259 X.260-X.269 X.270-X.279 X.280-X.289 X.290-X.299 X.300-X. 349 X.350-X.399 X.400-X.499 X.500-X.599 X

5、.600-X.629 Efficiency X.630-X.639 9 Naming, Addressing and Registration Abstract Syntax Notation One (ASN.l) OS1 MANAGEMENT Systems Management framework and architecture Management Communication Service and Protocol Structure of Management Information Management functions and ODMA functions SECURITY

6、 OS1 APPLICATIONS Commitment, Concurrency and Recovery Transaction processing Remote operations OPEN DISTRIBUTED PROCESSING X.650-X.679 X.680-X.699 X.700-X.709 X.710-X.719 X.720-X.729 X.730-X.799 X.800-X. 849 X.850-X.859 X.860-X.879 X.880-X.899 X.900-X.999 For further details, please refer to ITU-T

7、List of Recommendations. STDmITU-T RECMN XmbLtL-ENGL 1997 m 48b259L Ob4835b Tb4 m INTERNATIONAL STANDARD 13236 ITU-T RECOMMENDATION X.641 INFORMATION TECHNOLOGY - QUALITY OF SERVICE: FRAMEWORK Summary This Recommendation I International Standard provides a common basis for the coordinated developmen

8、t and enhancement of a wide range of standards that specify or reference Qualiy of Service (QOS) requirements or mechanisms. It offers a means of developing or enhancing standards related to QOS and provides concepts and terminology that will assist in maintaining the consistency of related standard

9、s. Source The IT-T Recommendation X.641 was approved on the 12th of December 1997. The identical text is also published as ISOAEC International Standard 13236. ITU-T Rec. X.641(1997 E) i STD-ITU-T RECMN X.643-ENGL 1997 4862593 0648357 9TO m FOREWORD ITU (International Telecommunication Union) is the

10、 United Nations Specialized Agency in the field of telecommuni- cations. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the IT. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standar

11、dizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by th

12、e Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administration

13、“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property R

14、ight. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the IT had not received notice o

15、f intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 1998 All rights reserved. No part o

16、f this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. Il ITU-T Rec. X.641(1997 E) 1 2 3 4 5 6 7 8 9 10 CONTENTS Scope Normative references . 2.1 Identical Recommendatio

17、ns I International Standards 2.2 Paired Recommendations I International Standards equivalent in technical content 2.3 Additional references Definitions 3.1 Basic Reference Model of Open Distributed Processing definitions 3.2 Basic Reference Model - OS1 Management Framework definitions 3.3 Service Co

18、nventions definitions . 3.4 OS1 Basic Reference Model definitions 3.5 QOS Framework definitions . Abbreviations . Concepts of this QOS Framework . 5.1 Introduction . 5.2 The service to which QOS applies 5.3 QOS characteristics . 5.4 User QOS requirements and QOS policies . 5.5 QOS requirements, QOS

19、parameters and QOS context 5.6 QOS management functions and QOS mechanisms . 5.7 QOS categories . 5.8 Initiation of QOS management . Definition of QOS characteristics 6.1 Introduction . 6.2 Aspects of QOS characteristic definition 6.3 QOS characteristics of general importance . 6.4 Fundamental QOS c

20、ategories QOS management 7.1 Introduction . 7.2 Prediction phase 7.3 Establishment phase 7.4 Operational phase 7.5 Supporting services . General QOS mechanisms . 8.1 Introduction . 8.2 Prediction phase mechanisms . 8.3 Establishment phase mechanisms . 8.4 Operational phase mechanisms . Specific QOS

21、requirements 9.1 QOS requirements related to single QOS characteristics 9.2 QOS verification 10.2 QOS verification concepts QOS requirements related to multiple characteristics . 10.1 Introduction and stages . Page 1 2 2 2 2 2 2 2 2 3 3 4 5 5 5 6 6 6 7 8 8 8 8 9 11 19 20 20 22 22 26 26 27 27 27 27 2

22、8 31 31 32 32 32 33 . ITU-T Rec . X.641(1997 E) 111 STDsITU-T RECMN Xmb41-ENGL 1777 H 4862571 Ob48357 773 = 11 Conformance. consistency and compliance 33 1 1.1 Conformance and the inter-relationship of standards . 11.2 Definitions 11.3 Application of consistency and compliance requirements 11.4 Cons

23、istency and compliance with ITU-T Rec . X.200 I ISODEC 7498-1 . Annex A . The model of QOS for OS1 . A.l Introduction . A.2 Architectural principles . A.3 Motivation for the provision of QOS A.4 Information flows in the model . AS Layer model of QOS for OS1 A.6 System model of QOS in OS1 . Annex B -

24、 Definitions of statistical derivations of Characteristics Annex C - Relationships between QOS Recommendations I International Standards and other Recommen- dations I International Standards Annex D - Cost Information . AnnexE - QOS Bibliography iv ITU-T Rec . X.641(1997 E) Page 33 33 34 34 35 35 35

25、 36 36 39 42 44 45 47 48 STDmITU-T RECMN Xmb41-ENGL 1997 m 48b2591 Ob483b0 495 m Introduction The purpose of this Recommendation I International Standard is to provide a common basis for the coordinated development and enhancement of the wide range of standards that specify or reference Quality of S

26、ervice (QOS) requirements or mechanisms in an Information Technology (IT) environment. It offers a means of developing or enhancing standards relating to QOS and provides concepts and terminology that will assist in maintaining the consistency of related standards. This Recommendation I Internationa

27、l Standard is complementary to existing IT-T Recommendations which define performance objectives and network signalling of QOS and it is not the intention of this Framework to lead to a need to revise any such Recommendations. The initial work in developing this Framework for QOS was done with the o

28、bjective of supplementing and clarifying the description of QOS contained in the Basic Reference Model of Open Systems Interconnection (OSI) (see IT-T Rec. X.200 I ISOAEC 7498-1). It is recognised, however, that management of QOS is important not only in OS1 communications but also in a much wider c

29、ontext, and that there is value in encouraging a common approach to QOS that can extend to other IT and communications architectures, to distributed processing in general and to Open Distributed Processing (ODP) in particular. Hence this Recommendation I International Standard is structured and writ

30、ten in such a way as to make it easy for many communities to adopt its approach, concepts, terminology and definitions. Its concepts and terms are defined without reference to any particular architecture, so that they can be adopted and applied by other communities to a variety of architectures and

31、protocols. This general treatment is supplemented by examples from OSI, ODP and elsewhere. To assist the OS1 community, Annex A defines how the general framework applies to the specific case of OS1 communications, both peer-to-peer and multi-peer. This QOS Framework contains an introduction, a scope

32、 and field of application and a set of QOS-related definitions and abbreviations. The concepts of QOS are introduced in clause 5, which also highlights user requirements. Clause 6 defines QOS characteristics with respect to the user requirements. Clauses 7, 8 and 9 cover QOS management, QOS mechanis

33、ms and the expression of specific QOS requirements, respectively. QOS verification is discussed in clause 1 O, and conformance, consistency and compliance are discussed in clause 1 1. Annexes are provided which stipulate: statistical derivations of characteristics; 0 a bibliography. the model of QOS

34、 for OSI; a standards structure with respect to QOS; a discussion of the issue of cost; and Other standards communities are encouraged to study this Recommendation I International Standard and, in the interests of consistency, to consider the adoption of the parts that are relevant to their field, w

35、hen this can be accomplished to good effect, without destabilisation of existing Recommendations I Intemational Standards. ITU-T Rec. X.641(1997 E) V STDeITU-T RECMN Xmb41-ENGL 1997 m 48b2591 Ob483b1 321 m ISO/IEC 13236 : 1998 (E) INTERNATIONAL STANDARD ITU-T RECOMMENDATION INFORMATION TECHNOLOGY -

36、QUALITY OF SERVICE: FRAMEWORK 1 Scope This QOS Framework is a structured collection of concepts and their relationships which describes QOS (Quality of Service) and enables the partitioning of, and relationships between, the topics relevant to QOS in Information Technology (IT) to be expressed by a

37、common means of description. In particular, this QOS Framework is directed at IT systems and their use in providing Open Distributed Processing services. This QOS Framework is intended to assist those designing and speci5ing IT systems, and those defining communications services and protocols, by pr

38、oviding guidance on QOS applicable to systems, services and resources of various kinds. It describes how QOS can be characterized, how QOS requirements can be specified, and how QOS can be managed. This QOS Framework defines terminology and concepts for QOS in IT. It introduces the concept of QOS ch

39、aracteristics, which represent the fundamental aspects of QOS that are to be managed in various ways; and it defines a number of QOS characteristics of particular importance. These defuiitions are independent of how QOS is represented or controlled in a real system. This Framework describes how QOS

40、requirements can be expressed, and identifies a number of QOS mechanisms (such as three-party negotiation) that can be used as components of QOS management functions to meet QOS requirements of various kinds. It also describes the circumstances in which various combinations of mechanisms may be appr

41、opriate. This QOS Framework provides a basis for the specification of extensions and enhancements to existing or planned standards, as a result of the need for, and application of, the QOS concepts defined in this Recommendation I International Standard. It is not the intent of this Recommendation I

42、 International Standard to destabilise any existing Recommendations I International Standards; rather, it is intended that this QOS Framework may be used by: developers of new or revised IT-related standards which define or use QOS mechanisms; and IT users expressing requirements for QOS. 0 This QOS

43、 Framework does not attempt to provide a basis for the specification of performance objectives or network signalling of QOS in public communications networks. The .QOS aspects of these communications services are addressed by other IT-T Recommendations. The intent of this Recommendation I Internatio

44、nal Standard is to provide a common vocabulary to both service providers and service users. Nothing in this Recommendation I International Standard should be construed as placing requirements on either service providers or service users. It is hoped that a common approach and vocabulary for QOS will

45、 assist multiple service providers to deliver end-to-end QOS to end-systems. This QOS Framework specifically excludes the detailed specification of QOS mechanisms. It is not the intent of this Recommendation I International Standard to serve as an implementation specification, to be a basis for appr

46、aising the conformance of implementations, or to define particular services and protocols. Rather, it provides a conceptual and functional framework for QOS which allows independent teams of experts to work productively on the development of Recommendations I International Standards. As applied to O

47、SI, this QOS Framework is consistent with the OS1 Basic Reference Model in that it describes operations and mechanisms which are assignable to layers as specified in the OS1 Basic Reference Model. It is consistent with the OS1 Management Framework (see ITLJ-T Rec. X.700 I ISOhEC 7498-4) and the Syst

48、ems Management Overview (see ITU-T Rec. X.701 I JSOIEC 10040) in its assignment of functions to management entities. In Annex A, this QOS Framework presents a model of QOS for OS1 which identifies the entities that participate in the management of QOS, defines the flow of QOS-related information bet

49、ween them and describes how this information is used. ITU-T Rec. X.641(1997 E) 1 STDmITU-T RECMN X.643-ENGL 3777 m 4862573 0648362 2b8 m ISOAEC 13236 : 1998 (E) 2 Normative references The following Recommendations and Intemational Standards contain provisions which, through reference in this text, constitute provisions of this Recommendation I 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 I International Standard are en