1、 International Telecommunication Union ITU-T I.371TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2004) SERIES I: INTEGRATED SERVICES DIGITAL NETWORK Overall network aspects and functions General network requirements and functions Traffic control and congestion control in B-ISDNITU-T Recommendat
2、ion I.371 ITU-T I-SERIES RECOMMENDATIONS INTEGRATED SERVICES DIGITAL NETWORK GENERAL STRUCTURE Terminology I.110I.119 Description of ISDNs I.120I.129 General modelling methods I.130I.139 Telecommunication network and service attributes I.140I.149 General description of asynchronous transfer mode I.1
3、50I.199 SERVICE CAPABILITIES Scope I.200I.209 General aspects of services in ISDN I.210I.219 Common aspects of services in the ISDN I.220I.229 Bearer services supported by an ISDN I.230I.239 Teleservices supported by an ISDN I.240I.249 Supplementary services in ISDN I.250I.259 OVERALL NETWORK ASPECT
4、S AND FUNCTIONS Network functional principles I.310I.319 Reference models I.320I.329 Numbering, addressing and routing I.330I.339 Connection types I.340I.349 Performance objectives I.350I.359 Protocol layer requirements I.360I.369 General network requirements and functions I.370I.399 ISDN USER-NETWO
5、RK INTERFACES Application of I-series Recommendations to ISDN user-network interfaces I.410I.429 Layer 1 Recommendations I.430I.439 Layer 2 Recommendations I.440I.449 Layer 3 Recommendations I.450I.459 Multiplexing, rate adaption and support of existing interfaces I.460I.469 Aspects of ISDN affectin
6、g terminal requirements I.470I.489 INTERNETWORK INTERFACES I.500I.599 MAINTENANCE PRINCIPLES I.600I.6B-ISDN EQUIPMENT ASPECTS ATM equipment I.730I.739 Transport functions I.740I.749 Management of ATM equipment I.750I.759 Multiplexing aspects I.760I.769 For further details, please refer to the list o
7、f ITU-T Recommendations. ITU-T Rec. I.371 (03/2004) i ITU-T Recommendation I.371 Traffic control and congestion control in B-ISDN Summary This Recommendation addresses functions and parameters for traffic and congestion control in the B-ISDN. A user-network and an inter-network traffic contract are
8、defined in terms of a traffic descriptor that includes traffic parameters and associated tolerances of an ATM layer transfer capability and of quality of service requirements associated to a QoS class. Relevant traffic parameters and generic conformance definitions for these parameters are specified
9、. ATM transfer capabilities that make use of these traffic parameters to allow for different combinations of QoS objectives and multiplexing schemes and specific conformance definitions applying to these ATM transfer capabilities are provided. In addition, traffic control and congestion control func
10、tions are further specified, among which are traffic parameter control functions at user-network and inter-network interfaces. Some specific traffic control interworking configurations are described. Finally, procedures for traffic control, congestion control and resource management are defined. Thi
11、s includes specific formats and information supported by resource management cells. Source ITU-T Recommendation I.371 was approved on 29 March 2004 by ITU-T Study Group 13 (2001-2004) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. I.371 (03/2004) FOREWORD The International Telecommunica
12、tion Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a v
13、iew to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommend
14、ations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for concis
15、eness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendatio
16、n is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INT
17、ELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights,
18、whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are ca
19、utioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2006 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. I.371 (03/2004
20、) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Abbreviations and terminology 2 3.1 Abbreviations . 2 3.2 Terminology . 5 3.3 External terminology 6 4 Introduction 6 4.1 General . 6 4.2 General objectives 7 4.3 Generic functions 7 4.4 A reference configuration for traffic control and congestion cont
21、rol. 9 4.5 Events, actions, time-scales and response times 10 4.6 Quality of service and network performance . 10 5 Traffic parameters and descriptors . 11 5.1 Definitions 11 5.2 Requirements 12 5.3 Traffic contract . 12 5.4 Traffic parameter specifications. 16 6 ATM transfer capabilities. 24 6.1 Ge
22、neral . 24 6.2 High level description of ATM transfer capabilities 25 6.3 Applicability of ATM transfer capabilities to applications 28 6.4 Deterministic bit rate transfer capability (DBR) 29 6.5 Statistical bit rate transfer capability (SBR). 34 6.6 ATM block transfer capabilities (ABT) . 39 6.7 Av
23、ailable bit rate transfer capability (ABR) 54 6.8 Guaranteed frame rate transfer capability (GFR). 65 7 Functions for traffic control and congestion control 69 7.1 Introduction 69 7.2 Traffic control functions. 70 7.3 Congestion control functions 83 7.4 Traffic control interworking functions . 84 8
24、Procedures for traffic control and congestion control 85 8.1 Resource management cell format . 85 8.2 RM cell error conditions. 86 iv ITU-T Rec. I.371 (03/2004) Page Annex A Generic Cell Rate Algorithm GCRA(T,). 87 A.1 Virtual Scheduling Algorithm (VSA) 87 A.2 Continuous-state leaky bucket algorithm
25、 . 88 Annex B Application of the GCRA to SBR conformance definition. 88 Annex C ABT/DT control messages across a standardized interface 92 Annex D ABT/IT control messages across a standardized interface 94 Annex E Avoidance of multiple outstanding BCR negotiations 96 Annex F ABR control messages acr
26、oss a standardized interface . 97 Appendix I Examples of application of the equivalent terminal for the peak cell rate definition. 99 I.1 Configuration 1. 99 I.2 Configuration 2. 101 Appendix II Transcoding rules from signalling information onto OAM traffic parameters at the ATM layer 103 Appendix I
27、II Throughput behaviour of the Generic Cell Rate Algorithm (GCRA). 104 Appendix IV UPC/NPC accuracy requirements. 105 Appendix V Examples of methods ensuring unicity of RM cell numbering in ABT. 106 V.1 Segmentation of the SN field between different networks. 106 V.2 Proprietary handling of SN field
28、 106 V.3 Segmentation of the SN field for indicating relative location of RM cell 107 Appendix VI Derivation of conformance definition parameters for ABT 108 Appendix VII Source, destination, and network element reference behaviours for ABR 110 VII.1 Source reference behaviour 110 VII.2 Destination
29、reference behaviour. 111 VII.3 Network element reference behaviour 112 VII.4 Impact of source reference behaviour on traffic characteristics. 113 Appendix VIII 2-store algorithm for determination of T(k) in ABR explicit mode. 114 VIII.1 2-store algorithm for determination of T(k) in ABR explicit mod
30、e . 114 VIII.2 Adjustment of ACR(t) based on the ECR field in backward RM cells 115 Appendix IX Applicability of ATM transfer capabilities to applications 116 Appendix X Additional material related to the F-GCRA . 118 X.1 The support of QoS commitments through F-GCRA. 118 X.2 Example implementation
31、illustrating how F-GCRA may be used to support QoS commitments . 119 X.3 Implementation limits for the case of many non-conforming frames 120 X.4 Proof of a result related to F-GCRA. 120 Appendix XI Providing GFR QoS with the CF-GCRA 121 Appendix XII Expectations of a GFR network element behaviour 1
32、22 ITU-T Rec. I.371 (03/2004) v Page Appendix XIII Applicability of GFR ATM Transfer Capability to applications . 123 Appendix XIV OAM support for GFR connections. 123 ITU-T Rec. I.371 (03/2004) 1 ITU-T Recommendation I.371 Traffic control and congestion control in B-ISDN 1 Scope This Recommendation
33、 describes traffic control and congestion control procedures for the B-ISDN at the ATM layer. ATM layer traffic control refers to all network actions aiming to meet the network performance objectives and negotiated QoS commitments, and to avoid congested conditions. ATM layer congestion control refe
34、rs to all network actions to minimize the intensity, spread and duration of congestion. This Recommendation provides a general description as well as objectives and procedures for traffic control and congestion control. Additionally, it describes the concepts of the traffic contract. It specifies th
35、e ATM transfer capabilities (ATCs) including, for each ATC, the applicable source traffic descriptor, associated tolerances and conformance definition. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provision
36、s of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations a
37、nd other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. 1 ITU-T Recommendation I.326 (2003), Functional architectu
38、re of transport networks based on ATM. 2 ITU-T Recommendation I.113 (1997), Vocabulary of terms for broadband aspects of ISDN. 3 ITU-T Recommendation I.150 (1999), B-ISDN asynchronous transfer mode functional characteristics. 4 ITU-T Recommendation I.311 (1996), B-ISDN general network aspects. 5 ITU
39、-T Recommendation I.321 (1991), B-ISDN protocol reference model and its application. 6 ITU-T Recommendation I.356 (2000), B-ISDN ATM layer cell transfer performance. 7 ITU-T Recommendation I.357 (2000), B-ISDN semi-permanent connection availability. 8 ITU-T Recommendation I.358 (2003), Call processi
40、ng performance for switched virtual channel connections (VCCs) in a B-ISDN. 9 ITU-T Recommendation I.361 (1999), B-ISDN ATM layer specification. 10 ITU-T Recommendations I.363.1 (1996), I.363.3 (1996) and I.363.5 (1996), B-ISDN ATM adaptation layer specification. 11 ITU-T Recommendation I.413 (1993)
41、, B-ISDN user-network interface. 12 ITU-T Recommendations I.432.1 (1999), I.432.2 (1999), I.432.3 (1999) and I.432.4 (1999), B-ISDN user-network interface Physical layer specification. 13 ITU-T Recommendation I.610 (1999), B-ISDN operation and maintenance principles and functions. 2 ITU-T Rec. I.371
42、 (03/2004) 14 ITU-T Recommendation I.630 (1999), ATM protection switching. 15 ITU-T Recommendation I.731 (2000), Types and general characteristics of ATM equipment. 16 ITU-T Recommendation I.732 (2000), Functional characteristics of ATM equipment. 17 ITU-T Recommendation Q.2650 (1999), Interworking
43、between Signalling System No. 7 Broadband ISDN User Part (B-ISUP) and Digital subscriber Signalling System No. 2 (DSS2). 18 ITU-T Recommendation Q.2660 (1999), Interworking between Signalling System No. 7 Broadband ISDN User Part (B-ISUP) and Narrow-band ISDN User Part (N-ISUP). 19 ITU-T Recommendat
44、ion Q.2761 (1999), Functional description of the B-ISDN User Part (B-ISUP) of Signalling System No. 7. 20 ITU-T Recommendation Q.2762 (1999), General functions of messages and signals of the B-ISDN User Part (B-ISUP) of Signalling System No. 7. 21 ITU-T Recommendation Q.2763 (1999), Signalling Syste
45、m No. 7 B-ISDN User Part (B-ISUP) Formats and codes. 22 ITU-T Recommendation Q.2764 (1999), Signalling System No. 7 B-ISDN User Part (B-ISUP) Basic call procedures. 23 ITU-T Recommendation Q.2931 (1995), Digital subscriber Signalling System No. 2 User-Network Interface (UNI) layer 3 specification fo
46、r basic call/connection control. 24 ITU-T Recommendations Q.2961.1 (1995) and Q.2961.2 (1997), Digital subscriber Signalling System No. 2 Additional traffic parameters. 25 ITU-T Recommendation Q.2962 (1998), Digital subscriber Signalling System No. 2 Connection characteristics negotiation during cal
47、l/connection establishment phase. 26 ITU-T Recommendation Q.2963.1 (1999), Digital subscriber Signalling System No. 2 Connection modification: Peak cell rate modification by the connection owner. 3 Abbreviations and terminology 3.1 Abbreviations This Recommendation uses the following abbreviations:
48、AAL ATM Adaptation Layer ABR Available Bit Rate ABT ATM Block Transfer ACR Allowed Cell Rate ADT ACR Decrease Time ATC ATM Transfer Capability ATM Asynchronous Transfer Mode ATM_PDU ATM Protocol Data Unit AUU ATM user to ATM user indication ITU-T Rec. I.361 BCR Block Cell Rate BECN Backward Explicit
49、 Congestion Notification ITU-T Rec. I.371 (03/2004) 3 B-ISDN Broadband ISDN B-NT1 Broadband Network Termination 1 B-NT2 Broadband Network Termination 2 B-TE Broadband Terminal Equipment CAC Connection Admission Control CBR Constant Bit Rate CCR Current Cell Rate CDV Cell Delay Variation CEQ Customer Equipment CF-GCRA Conforming Cell F-GCRA (Appendix XI) CI Congestion Indication CLP Cell Loss Priority (bit) CLR Cell Loss Ratio CRC Cyclic Redundancy Chec
