1、 STD-ITU-T RECMN X-642-ENGL 1998 4862591 0659968 Tb7 9 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STAN DARD IZATION SECTOR OF ITU X.642 (09/98) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS OS1 networking and system aspects - Quality of service Information technology - Qu
2、ality of Service - Guide to methods and mechanisms ITU-T Recommendation X.642 (Previously CCITT Recommendation) STD.ITU-T RECMN Xab42-ENGL 1998 48b2591 Ob59969 9T3 ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS PUBLIC DATA NETWORKS Services and facilities Interfaces Tran
3、smission, signalling and switching Network aspects Maintenance Administrative arrangements OPEN SYSTEMS INTERCONNECTION Model and notation Service definitions Connection-mode protocol specifications Connectionless-mode protocol specifications PICS proformas Protocol Identification Security Protocols
4、 Layer Managed Objects Conformance testing General Satellite data transmission systems MESSAGE HANDLING SYSTEMS DIRECTORY OS1 NETWORKING AND SYSTEM ASPECTS INTERWORKING BETWEEN NETWORKS 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.210-X.219 X.220-X.2
5、29 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.600-X.629 Fffirimrv X.630-X.639 -_-.-.-_.- Quality of service x.640-x.649 Naming, Addressing and Registration Abstract Syntax Notation One (ASN. 1) Systems Management framewo
6、rk and architecture Management Communication Service and Protocol Structure of Management Information Management functions and ODMA functions OS1 MANAGEMENT SECURITY OS1 APPLICATIONS Commitment, Concurrency and Recovery Transaction processing Remote operations OPEN DISTRIBUTED PROCESSING X.650-X.679
7、 X.680-X. 699 X.700-X.709 X.7 10-X.7 19 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 List of Recommendations. TECHNICAL REPORT 13243 ITU-T RECOMMENDATION X.642 IMFORMATION TECHNOLOGY - QUALITY OF SERVICE - GUIDE TO ME
8、THODS AND MECHANISMS Summary This Recommendation I Technical Report promotes the use of common methods and mechanisms for managing Quality of Service in information technology and data communications services and protocols. These methods and mechanisms are consistent with the overall Quality of Serv
9、ice Framework given in ITU-T Rec. X.641 I ISOAEC 13236. Source The ITU-T Recommendation X.642 was approved on the 25th of September 1998. The identical text is also published as ISODEC Technical Report 13243. ITU-T Rec. X.642 (1998 E) i STDmITU-T RECMN Xob42-ENGL 1998 48b2591 Ob59971 551 9 FOREWORD
10、IT (International Telecommunication Union) is the 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 IT-T is responsible for studying technical, operating and tariff questions and issuin
11、g Recommendations on them with a view to standardizing 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 the
12、se topics. The approval of Recommendations by the 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 thi
13、s Recommendation, the expression “Administration“ 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 invo
14、lve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by IT members or others outside of the Recommendation development process. As of the date of approval of this R
15、ecommendation, the IT had not received notice of 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 data
16、base. O ITU 1999 All rights reserved. No part of 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. ITU-T Rec. X.642 (1998 E) 11 1 2 3 4 5 6 7 8 9 10 STDmITU-T RECMN X
17、mb42-ENGL 3998 4862593 0659372 498 CONTENTS Scope Normative references 2.1 Identical Recommendations I International Standards . Definitions 3.1 QoS Framework definitions 3.2 ODP definitions . Abbreviations . References to QoS from Recommendations, International Standards and other specifications .
18、5.1 QoS in collaborative IT-T Recommendations and ISO/IEC International Standards 5.2 5.3 5.4 QoS in IT-T Recommendations 5.5 QoS in specifications produced by other organizations 5.6 Research on QoS management Methods and mechanisms for the prediction phase Methods and mechanisms for the establishm
19、ent phase 7.1 Methods of reaching QoS agreements . 7.2 Resource allocation mechanisms . 7.3 Initialization mechanisms Methods and mechanisms for the operational phase 8.1 Monitoring mechanisms 8.2 Maintenance mechanisms 8.3 Filters . 8.4 Enquiry mechanisms . 8.5 Alert mechanisms QoS verification met
20、hods . 9.1 Introduction . 9.2 9.3 QoS verification at the testing stage QoS in ISO/IEC International Standardized Profiles QoS in IS0 TC 184 standards . QoS verification at the design stage Page 1 1 2 2 2 2 3 3 3 8 8 8 9 10 10 10 10 22 22 22 22 23 24 25 25 26 26 26 27 9.4 QoS verification at the ope
21、ration stage . 28 References to this Recommendation I Technical Report 28 ITU-T Rec . X.642 (1998 E) . 111 STD-ITU-T RECMN X=b42-ENGL 3798 4862593 0659973 324 - Introduction This Recommendation I Technical Report is intended to promote the use of common methods and mechanisms for managing Quality of
22、 Service (QoS) in a number of different communications and systems environments. The collaborative ITU-T and ISOAEC JTC 1 project for coordination and harmonization of QoS-related initiatives is aimed at encouraging the use of the QoS Framework (see IT-T Rec. X.641 I ISO/IEC 13236), facilitating the
23、 use of common QoS methods and mechanisms, and promoting consistency between different applications and systems in their treatment of QoS. The collaboration has been extended to include QoS in Open Distributed Processing. Efforts are being made to promote maximum consistency between this activity an
24、d the work on development of specifications for QoS in CORBA-based systems in the Object Management Group (OMG). Organizations developing methods or mechanisms for QoS management are encouraged to make use of the concepts and terms defined in the QoS Framework. Any developments that may be re-usable
25、 in other contexts should also be proposed for reference in this Recommendation I Technical Report by submitting a reference, together with explanatory text, to the IT-T or JTC 1 Secretariat. It is expected that the convergence of QoS methods and mechanisms will be achieved in a stepwise fashion, us
26、ing such submitted material as a basis. In its first edition, this Recommendation I Technical Report identifies and catalogues current standards and other widely available specifications that incorporate definitions of QoS characteristics and QoS methods and mechanisms; and it includes definitions o
27、f some methods and mechanisms that are considered to be widely applicable. These methods and mechanisms are derived from those used or under development in information technology standards, and have been formulated in a manner consistent with the QoS Framework, with the objective that they can be ap
28、plied widely and, if appropriate, standardized. Subsequent editions of this Recommendation I Technical Report are expected to add further methods and mechanisms, likewise formulated in a manner consistent with the QoS Framework. Through this process, harmonization of QoS approaches and usage across
29、a wide range of environments will be achieved. Since this Recommendation I Technical Report includes methods and mechanisms developed elsewhere, in cases of conflict between definitions in this Recommendation I Technical Report and definitions in the source specifications, the latter have precedence
30、. iv ITU-T Rec. X.642 (1998 E) STD-ITU-T RECMN X.642-ENGL 1998 m 4862591 0659974 2b0 W ISOKEC TR 13243 : 1999 (E) TECHNICAL REPORT ITTJ-T RECOMMENDATION INFORMATION TECHNOLOGY - QUALITY OF SERVICE - GUIDE TO METHODS AND MECHANISMS 1 Scope This Recommendation I Technical Report uses the concepts and
31、terminology of the Quality of Service Framework, IT-T Rec. X.641 I ISO/IEC 13236. It is intended to support those designing, testing and specifying Information Technology (IT) systems, data communications services and protocols, those defining QoS management functions and QoS mechanisms for particul
32、ar data environments and technologies, and those engaged in other QoS-related activities such as system testing, by providing a source of reference material on QoS. To do this, it brings together references to methods and mechanisms from a variety of sources, and in some cases documents them in a st
33、yle which will permit their use in many data different environments. The term “method“ is used in a very general sense to include any process, function, etc., that is relevant to QoS at any stage in the life-cycle of a system. The criterion for reference to or inclusion of definitions or specificati
34、ons of QoS methods and mechanisms in this Recommendation I Technical Report is that they are thought to be of potentially wider application than solely the environment for which they were originally developed, although still in a data context. Clause 5 identifies sources of definitions of QoS charac
35、teristics and related information. Clauses 6, 7 and 8 discuss methods and mechanisms appropriate to the phases of QoS activity that are defined in the QoS Framework: clause 6 deals with the prediction phase, clause 7 with the establishment phase and clause 8 with the operational phase. Clause 9 desc
36、ribes methods for verification of system behaviour related to QoS. Clause 10 covers the relationships between this Recommendation I Technical Report and Recommendations, International Standards or Technical Reports that reference it. This Recommendation I Technical Report contains detailed definitio
37、ns of some QoS mechanisms. Some peer-to-peer QoS negotiation mechanisms are defined in 7.1.1. These involve two peer entities and in most cases also the provider of a communications service between them. Subclause 7.1.2 provides an initial specification of some QoS negotiation mechanisms for 1 x N m
38、ulticast connections, based on those in 7.1.1. Subclause 7.1.3 discusses QoS negotiation mechanisms for M x N multicast, some of which can make use of those in 7.1.2. Subclause 8.2.1 defines some QoS management mechanisms to support time-critical applications. This Recommendation I Technical Report
39、does not include methods and mechanisms for security. 2 Normative references The following Recommendations and International Standards contain provisions which, through reference in this text, constitute provisions of this Recommendation I Technical Report. At the time of publication, the editions i
40、ndicated were valid. All Recommendations and Standards are subject to revision, and parties to agreements based on this Recommendation I Technical Report are encouraged to investigate the possibility of applying the most recent edition of the Recommendations and Standards listed below. Members of IE
41、C and IS0 maintain registers of currently valid International Standards. The Telecommunication Standardization Bureau of the ITU maintains a list of currently valid IT-T Recommendations. ITU-T Rec. X.642 (1998 E) 1 STD-ITU-T RECMN Xab42-ENtL 1778 Lid62593 Ob59975 lT7 ISODEC TR 13243 : 1999 (E) 2.1 I
42、dentical Recommendations I International Standards - IT-T Recommendation X.641 (1997) I ISOAEC 13236:1998, Information technology - Quality of Service: Framework. ITU-T Recommendation X.902 (1995) I ISO/IEC 10746-2:1996, Information technology - Open distributed processing - Reference Model: Foundat
43、ions. - 3 Definitions For the purposes of this Recommendation I Technical Report, the following definitions apply. 3.1 QoS Framework definitions This Recommendation I Technical Report uses the following terms drawn from the Quality of Service Framework, -T Rec. X.641 I ISO/IEC 13236: - compulsory (l
44、evel of agreement); - connection-wide (negotiation); - controlled highest quality; - establishment phase; - guaranteed (level of agreement); - highest quality attainable; - lowest quality acceptable; - operating target; - operational phase; - prediction phase; - QoSalert; - QoS characteristic; - QoS
45、enquiry; - QoS filter; - QoS maintenance; - QoS measure; - QoS mechanism; - QoS monitoring; - QoS negotiation; - QoS parameter; - QoS threshold; - QoS verification; - receiver-selected (negotiation). 3.2 ODP definitions This Recommendation I Technical Report uses the following term drawn from the Re
46、ference Model of Open Distributed Processing: Foundations, ITU-T Rec. X.902 I ISO/IEC 10746-2: - Quality of Service (QoS): A set of qualities related to the collective behaviour of one or more objects. 2 ITU-T Rec. X.642 (1998 E) STD-ITU-T RECMN X.642-ENGL 1998 - 4b259L 0657776 033 II ISO/iEC TR 132
47、43 : 1999 (E) 4 Abbreviations For the purposes of this Recommendation I Technical Report, the following abbreviations apply: AGI CHQ CORBA cw FDT HQA LQA ODP OMG PCO packet-switched networks (e.g. those conforming to the ITU-T Rec. X.25); local and metropolitan area networks following the ISOAEC 880
48、2 family of standards; frame relay and broadband ISDN networks; simple peer-to-peer and multipeer data-links. Many Recommendations I Intemational Standards in this area make reference to various aspects of QoS. Table 5-1 lists the Recommendations I International Standards and shows which QoS charact
49、eristics they define or use. Table 5-2 provides a reverse index to the source documents: it lists the QoS characteristics or related QoS parameters that have been defined in the Recommendations I International Standards and identifies the documents in which they can be found. In addition, there is a where-used table in 7.1.1.2 (Table 7-l), which identifies the Recommendations I International Standards that utilize the QoS mechanisms defined in that subclause. ITU-T Rec. X.642 (1998 E) 3 Table 5-1 - QoS characteristics and parameters in joint ITU-T and ISOAEC lower layer stand
