1、NTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STAN DARD IZATION SECTOR OF ITU 1.356 (03/2000) SERIES I: INTEGRATED SERVICES DIGITAL NETWORK Overall network aspects and functions - Performance objectives B-ISDN ATM layer cell transfer performance ITU-T Recommendation 1.356 (Formerly CC
2、ITT Recommendation) ITU-T I-SERIES RECOMMENDATIONS INTEGRATED SERVICES DIGITAL NETWORK GENERAL STRUCTURE Terminology Description of ISDNs General modelling methods Telecommunication network and service attributes General description of asynchronous transfer mode Scope General aspects of services in
3、ISDN Common aspects of services in the ISDN Bearer services supported by an ISDN Teleservices supported by an ISDN Supplementary services in ISDN Network functional pnnciples Reference models Numbering, addressing and routing Connection types Performance objectives Protocol layer requirements Genera
4、l network requirements and functions Application of I-series Recommendations to ISDN user-network interfaces Layer 1 Recommendations Layer 2 Recommendations Layer 3 Recommendations Multiplexing, rate adaption and support of existing interfaces Aspects of ISDN affecting terminal requirements SERVICE
5、CAPABILITIES OVERALL NETWORK ASPECTS AND FUNCTIONS ISDN USER-NETWORK INTERFACES INTERNETWORK INTERFACES MAINTENANCE PRINCIPLES B-ISDN EQUIPMENT ASPECTS ATM equipment Transport functions Management of ATM equipment 1.110-1.119 1.120-1.129 I. 1 30-1.1 39 I. 140-1.149 1.150-1.199 1.200-1.209 1.2 10-1.2
6、 19 1.220-1.229 1.230-1.239 1.240-1.249 1.250-1.299 1.3 10-1.3 19 1.320-1.329 1.330-1.339 1.340-1.349 1.3561359 1.360-1.369 1.370-1.399 1.420-1.429 1.430-1.439 1.440-1.449 1.450-1.459 1.460-1.469 1.470-1.499 I. 500-1.599 1.600-1.699 1.730-1.739 1.740-1.749 1.750-1.799 For further details, please ref
7、er to the list ofTU-T Recommendations. ITU-T Recommendation 1.356 B-ISDN ATM layer cell transfer performance Summary This Recommendation defines parameters for quantifying the ATM cell transfer Performance of a broadband ISDN connection. It includes adjusted parameter definitions that might be used
8、when cells do not conform with the negotiated traffic contract. This Recommendation includes provisional performance objectives for cell transfer, some of which depend on the users selection of quality-of- service (QoS) class. Recommendation includes the definitions for those QoS classes. Finally, e
9、ach performance objective is allocated to the individual national portions involved in providing the international connection. Annexes A, B, C and D provide information about ATM adaptation layer performance, information about factors contributing to cell transfer delay and cell delay variation, inf
10、ormation about performance measurement methods, and information about QoS preferences conveyed through signalling. Source ITU-T Recommendation 1.356 was revised by ITU-T Study Group 13 (1997-2000) and approved under the WTSC Resolution 1 procedure on 1 O March 2000. Keywords AAL performance, ATM, AT
11、M performance, ATM transfer capabilities, B-ISDN, B-ISDN performance, cell block, cell delay variation (CDV), cell error ratio (CER), cell loss ratio (CLR), cell misinsertion rate (CMR), cell transfer delay (CTD), cell transfer outcome, errored cell, hypothetical reference connection (HRX), internat
12、ional portion, lost cell, misinserted cell, national portion, network performance (NP), performance, performance allocation, performance measurement, performance monitoring, performance objectives, quality of service (QoS), quality of service class, quality of service negotiation, severely errored c
13、ell block, severely errored cell block ratio (SECBR), successfully transferred cell, tagged cell, unbounded performance, unspecified performance. FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunic
14、ation 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 view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conferen
15、ce (WTSC), 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 Recommendations is covered by the procedure laid down in WTSC Resolution 1. In some areas of information technology which
16、 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“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPER
17、TY 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, whether asserted
18、 by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that
19、 this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. o ITU 2001 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, w
20、ithout permission in writing from the ITU. CONTENTS Page 1 Scope 1 2 References 3 Abbreviations . 4 Performance model . 4.,1 Measurement points and connection portions 4.2 Cell-based ATM reference events 4.3 Frame-based ATM reference events . 4.4 Layered nature of B-ISDN performance . : 5 5.1 ATM ce
21、ll transfer outcomes . Successful cell transfer outcome 5.2 Tagged cell outcome . 5.3 Errored cell outcome i . 5.4 Lost cell outcome . 5.5 Misinserted cell outcome . 5.6 Severely errored cell block outcome . 5.7 Successful and corrupted f-ame outcomes . 6 ATM performance parameters eil Cell error ra
22、tio 6.3 6.4 6.5 6.6 6.7 7 7.1 7.2 Cell loss ratio 6.2.1 CLb 6.2.2 CLRo+i 6.2.3 CLRI Cell misinsertion rate Severely errored cell block ratio . Cell transfer delay . 6i5.1 Mean cell transfer delay 6.5.2 Cell delay variation . Cell flow related parameters . Frame-based ATM parameters . Network perform
23、ance when some cells are non-conforming . A method for computing the number of non-conforming cells Upper bounding the number of non-conforming cells . 7.2.1 Bounding cell non-conformance for a single peak cell rate specification 1 2 8 9 10 10 10 10 10 11 12 12 12 12 12 12 13 13 13 13 13 16 16 16 16
24、 19 19 Page 7.2.2 7.2.3 7.2.4 Bounding cell non-conformance for independent peak cell rate Bounding cell non-conformance for dependent, coordinated cell rate Bounding cell non-conformance for dependent, coordinated cell rate specifications . specifications defined on the aggregate cell stream specif
25、ications defined on the aggregate and on the CLP = O substream . Adjusted CLR performance when there are non-conforming cells 7.3 7.3.1 7.3.2 CLR when the conformance specification applies to a single cell stream CLR when the conformance specification applies to the aggregate and the CLP = O substre
26、am 7.4 Non-conforming cells and the severely errored cell block outcome 8 Network performance objectives 8.1 General discussion of per-connection QoS 8.2 QoS classes . 8.2.1 Nature of the network performance objectives . 8.2.2 Statistical estimation issues . 8.2.3 Unbounded (unspecified) performance
27、 . Default values for cell error ratio, cell misinsertion rate, and severely errored cell block ratio Association of QoS classes with ATM transfer capabilities . Alternative QoS negotiation procedures . Allocation of the performance objectives . General pnnciples of allocation Allocation of the QoS
28、class 1 and QoS class 5 CTD objectives Allocation of the QoS class 1 CDV objective 8.2.4 8.2.5 8.3 9 9.1 9.2 Route length calculation . 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.1 O Allocation of the QoS class 5 CDV objective Allocation of the SECBR and CER objectives . Allocation of the QoS class 1 and QoS cla
29、ss 5 CLR objectives Allocation of the QoS class 2 and QoS class 3 CLR objectives Concatenation of QoS values . Allocation of the CMR objective . Annex A . Relationship between ATM layer NF and the NP of AAL type 1 for CBR A . 1 services . . Possible AAL functions and their effects A . 1.1 A . 1.2 A
30、. 1.3 Lost cell outcome and misinserted cell outcome Errored cell outcome . Cell transfer delay . 20 20 20 21 21 22 22 22 23 23 23 24 24 24 26 27 27 27 28 28 29 29 30 31 31 32 32 32 32 32 32 33 A.2 Bounding relationships between NP parameters and binary errors Annex B . Cell transfer delay. I-point
31、CDV. and 2-point CDV characteristics . B . 1 Components of delay associated with ATM-based user information transfer . B.2 B.3 B.4 Annex C - Cell transfer performance measurement methods . Relationship between cell clumping and cell queues . 1 -point CDV and non-conformance . Relationship between ce
32、ll transfer delay and cell loss in a single shared buffer c . 1 c.2 c.3 c . 4 c.5 C.6 c.7 C.8 c.9 c.10 Performance measurements and availability General aspects of performance monitoring using OAM cells General aspects of out-of-service performance measurement Cell error ratio Cell loss ratio . Cell
33、 misinsertion rate Severely errored cell block ratio . Cell transfer delay . Cell delay vanation . Estimation of CLR and SECBR in case of lost FM OAM cells . Annex D . Signalling QoS Preferences DA Signalling preferences for a QoS class . . T D.2. Signalling of individual parameters D.2.1 D.2.2 Inte
34、rpretation of the fields that contain supplementary information about individual parameters Limits on the applicability of fields containing supplementary information about individual parameters endix . I . Assessing the performance of a UPC/NPC mechanism endix II . Hypothetical reference connection
35、s for validating the ATM performance objectives Number ATM nodes in the HRXs Switching speeds in the HRXs . Loading within the HRXs . , . Geostationary satellites within the HRXs . , IL5 . Other aspects of the HRXs . I: Appendix III . Example applications of the allocation rules of 9.6, . 9.7 and 9.
36、8 Page 33 33 33 34 34 34 35 36 36 39 39 40 40 41 41 42 43 46 46 46 46 48 48 49 50 51 51 51 52 52 Appendix IV . Intenvorking with downstream ATM Forum domains . IV . 1 ATM Forum service categories IV.2 ATM Forum fields for signalling of individual performance parameters Page 53 53 54 ITU-T Recommenda
37、tion 1.356 B-ISDN ATM layer cell transfer performance 1 Scope This Recommendation defines speed, accuracy, and dependability performance parameters for cell transfer in the ATM layer of a broadband ISDN. The defined parameters apply to end-to-end ATM connections and to specified portions of such con
38、nections. The parameters are defined on the basis of ATM cell transfer reference events which may be observed at physical interfaces between ATM networks and associated customer equipment, and at physical interfaces between ATM networks. NOTE 1 -The parameters defined in this Recommendation may be a
39、ugmented or modified based upon further study of the requirements of the services to be supported on broadband ISDNs. NOTE 2 -The parameters defined in clause 6 apply to cell streams in which all cells conform with the negotiated ITU-T 1.371 traffic contract. Clause 7 illustrates one way of extendin
40、g the definitions and measurement methods to cell streams in which some cells do not conform with the traffic contract. It is recognized that further work is needed in this area. NOTE 3 - The performance objectives and allocations are intended to characterize ATM connections in the available state.
41、Availability decision parameters and associated availability parameters and their objectives are the subject of ITU-T 1.357. NOTE 4 - The performance objectives and allocations are design objectives and thus are expected to be achieved by a high percentage of network connections. They are not, howev
42、er, intended to be guaranteed on a per-switched-connection basis. Clause 8 recommends ATM performance values to be achieved internationally for each of the defined parameters. Some of these values depend on which Quality of Service (QoS) class the end- users and network providers agree on for the co
43、nnection. Clause 8 defines five different QoS classes. lause 9 provides guidance on the allocated performance levels that each specified portion should ide in order to achieve the recommended end-to-end international performance. material in clauses 4-7 is equally applicable to international virtual
44、 channel connections (VCC) d international virtual path connections (VPC). The international objectives and allocations in s 8 and 9 are also applicable to both VCCs and VPCs. However, the end users (customers) of ernational VPC will often be two networks that use the VPC to support individual VCCs.
45、 In to meet the end-to-end objectives on each VCC, the performance of the supporting VPC must etter. The degree to which the VPC performance must be better is for further study. llowing ITU-T Recommendations and other references contain provisions which, through nce in this text, constitute provisio
46、ns of this Recommendation. At the time of publication, the cated were valid. All Recommendations and other references are subject to revision; Recommendation are therefore encouraged to investigate the possibility of applying the ecent edition of the Recommendations and other references listed below
47、. A list of the currently valid ITU-T Recommendations is regularly published. i 2 ITU-T G. 1 14 (2000), One-way transmission time. ITU-T G.826 (1 999), Error pelSormance parameters and objectives for international, constant bit rate digital paths at or above the primary rate. ITU-T G.828 (2000), Err
48、or performance parameters and objectives for international, constant bit rate synchronous digital paths. ITU-T I. 1 13 (1 997), Vocabulary of terms for broadband aspects of ISDN. ITU-T I. 150 (1 999), B-ISDN asynchronous transfer mode functional characteristics. ITU-T 1.3 1 1 (1 996), B-ISDN general
49、 network aspects. ITU-T 1.321 (1991), B-ISDNprotocol reference model and its application. ITU-T 1.350 (1993), General aspects of quality of service and network performance in digital networks, including ISDNs. ITU-T 1-35 lN.801N.1501 (2000), Relationships among ISDN, Internet protocol and GIL performance Recommendations. ITU-T 1.357 (2000), B-ISDN semi-permanent connection availability. ITU-T 1.363.1 (1996), B-ISDN ATM adaptation layer specification - Type 1 AAL. ITU-T 1.371 (2000), Traffic control and congestion control in B-ISDN. ITU-T 1.41 3 (1 993), B-ISDN user-network
