1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T X.144TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2003) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS Public data networks Network aspects User information transfer performance parameters for public frame relay data networksITU-T Recommend
2、ation X.144 ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS PUBLIC DATA NETWORKS Services and facilities X.1X.19 Interfaces X.20X.49 Transmission, signalling and switching X.50X.89 Network aspects X.90X.149 Maintenance X.150X.179 Administrative arrangements X.180X.199 OPE
3、N SYSTEMS INTERCONNECTION Model and notation X.200X.209 Service definitions X.210X.219 Connection-mode protocol specifications X.220X.229 Connectionless-mode protocol specifications X.230X.239 PICS proformas X.240X.259 Protocol Identification X.260X.269 Security Protocols X.270X.279 Layer Managed Ob
4、jects X.280X.289 Conformance testing X.290X.299 INTERWORKING BETWEEN NETWORKS General X.300X.349 Satellite data transmission systems X.350X.369 IP-based networks X.370X.399 MESSAGE HANDLING SYSTEMS X.400X.499 DIRECTORY X.500X.599 OSI NETWORKING AND SYSTEM ASPECTS Networking X.600X.629 Efficiency X.6
5、30X.639 Quality of service X.640X.649 Naming, Addressing and Registration X.650X.679 Abstract Syntax Notation One (ASN.1) X.680X.699 OSI MANAGEMENT Systems Management framework and architecture X.700X.709 Management Communication Service and Protocol X.710X.719 Structure of Management Information X.
6、720X.729 Management functions and ODMA functions X.730X.799 SECURITY X.800X.849 OSI APPLICATIONS Commitment, Concurrency and Recovery X.850X.859 Transaction processing X.860X.879 Remote operations X.880X.899 OPEN DISTRIBUTED PROCESSING X.900X.999 For further details, please refer to the list of ITU-
7、T Recommendations. ITU-T Rec. X.144 (10/2003) i ITU-T Recommendation X.144 User information transfer performance parameters for public frame relay data networks Summary This Recommendation defines speed, accuracy and dependability performance parameters that may be used in specifying and assessing t
8、he user information transfer performance of public frame relay data networks. The defined performance parameters are applicable to both PVC and SVC services. This revision was undertaken to take into account the development of ITU-T Rec. X.147 which specifies network availability objective values to
9、gether with techniques for assessing frame relay network availability. Information previously pertaining to availability has been moved to ITU-T Rec. X.147. References have been updated to take into account the development of ITU-T Rec. X.146 which specifies performance objectives and classes of ser
10、vice, and of ITU-T Rec. X.148 which defines measurement techniques. Source ITU-T Recommendation X.144 was approved on 29 October 2003 by ITU-T Study Group 17 (2001-2004) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. X.144 (10/2003) FOREWORD The International Telecommunication Union (IT
11、U) 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 view to standar
12、dizing 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 Recommendations is cove
13、red 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 conciseness to indic
14、ate 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 Recommendation is achieved
15、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. INTELLECTUAL PROP
16、ERTY 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 assert
17、ed 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 th
18、at this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2004 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. X.144 (10/2003) iii CONT
19、ENTS Page 1 Scope 1 2 References. 3 3 Abbreviations 4 4 Generic performance model . 5 4.1 Components of an end-to-end connection 5 4.2 Frame transfer reference events 6 4.3 Frame transfer outcomes 7 5 Frame transfer performance parameters . 8 5.1 User information frame transfer delay . 11 5.2 User i
20、nformation frame delay jitter 11 5.3 User information frame loss ratio. 12 5.4 Residual frame error ratio. 13 5.5 Extra frame rate 13 5.6 Frame-based conformant traffic distortion ratio. 13 5.7 Frame flow-related parameters. 14 Annex A Conformance test for performance evaluation 15 A.1 Motivation 15
21、 A.2 Limited standardized use 15 A.3 DDB definition . 15 A.4 Using the DDB in evaluating FCTDR 16 Annex B Bit-based accuracy and dependability parameters. 18 B.1 User information bit loss ratio 18 B.2 Residual bit error ratio 18 Annex C Some relations between frame-level and ATM-level performance pa
22、rameters 20 C.1 Scope 20 C.2 Motivation for relating frame-level and ATM-level and performance parameters. 20 C.3 Frame relay parameters considered 21 C.4 Relation between FR and ATM user information loss parameters 22 Appendix I Congestion notification 25 I.1 The effects of FECN, BECN and CLLM on p
23、erformance. 25 I.2 Controlling the effects on performance 25 Appendix II Performance effects of excessive demand for connection resources . 26 II.1 Unanticipated simultaneous access line bursting . 26 II.2 Full utilization of over-subscribed access lines 26 Appendix III A method for estimating the F
24、LR: FLR extraction. 26 III.1 FLR extraction methodology limitations 26 III.2 FLR extraction methodology 27 ITU-T Rec. X.144 (10/2003) 1 ITU-T Recommendation X.144 User information transfer performance parameters for public frame relay data networks 1 Scope This Recommendation defines speed, accuracy
25、 and dependability performance parameters that may be used in specifying and assessing the user information transfer performance of public frame relay data networks. The defined parameters apply to end-to-end and point-to-point frame relay connections1, and to specified portions of such connections
26、when provided in accordance with ITU-T Recs X.36 and X.76. The performance parameters defined in this Recommendation are intended to be used in the planning of international frame relay services. The intended users of this Recommendation include frame relay service providers, equipment manufacturers
27、 and end users. This Recommendation may be used: 1) by service providers in the planning, development and assessment of frame relay services to ensure that the achieved performance meet users needs; 2) by equipment manufacturers as performance metrics that will affect equipment design; and 3) by use
28、rs in evaluating performance. The scope of this Recommendation is summarized in Figure 1. The frame relay performance parameters are defined on the basis of frame transfer reference events that may be observed at physical interfaces associated with specified boundaries. For comparability and complet
29、eness, frame relay performance is considered in the context of the 3 3 performance matrix defined in ITU-T Rec. X.140. Three protocol-independent data communication functions are identified in the matrix: connection set up, user information transfer and disengagement. Each function is considered wit
30、h respect to three general performance concerns (or “performance criteria“): speed; accuracy; and dependability. An associated two-state model provides a basis for describing service availability (see ITU-T Rec. X.147) The performance parameters defined in this Recommendation define the speed, accur
31、acy, and dependability of the user information transfer provided by frame relay networks. The user transfer performance parameters are applicable to both PVCs and SVCs. ITU-T Rec. X.145 defines the speed, accuracy and dependability of the connection set-up and the disengagement phase of frame relay
32、Switched Virtual Connections (SVC). ITU-T Rec. X.146 specifies performance objectives and quality of service classes applicable to frame relay. ITU-T Rec. X.147 specifies objectives and methods for assessing network availability of frame relay services. _ 1In the context of this Recommendation, a fr
33、ame relay connection (denoted hereafter, unless noted otherwise, by the term “connection“) refers to a virtual connection established between two specified end points. 2 ITU-T Rec. X.144 (10/2003) ITU-T Rec. X.148 specifies procedures for measuring the performance of public frame relay data networks
34、. NOTE 1 The parameters defined in this Recommendation may be augmented or modified based upon further study of the requirements for quantify the performance of frame relay networks. NOTE 2 The defined parameters are intended to characterize frame relay connections in the available state. NOTE 3 The
35、 parameters of this Recommendation are designed to measure the performance of network elements between pairs of section boundaries. However, users of this Recommendation should be aware that the behaviour of connection elements outside the pair of boundaries can adversely influence the measured perf
36、ormance of the elements between the boundaries. Examples are described in Appendix III. This Recommendation is organized as follows: Clause 2 presents references. Clause 3 presents abbreviations. Clause 4 defines a performance model and a set of frame transfer reference events (FEs) that provide a b
37、asis for performance parameter definition. Clause 5 defines frame-based speed of service, accuracy and dependability parameters using the frame transfer reference events defined in clause 4. Annex A presents a test for judging traffic conformance for performance assessment purposes. Annex B defines
38、bit-based accuracy and dependability parameters associated with the transfer of user information in frame relay services. Annex C gives some relations between frame-level and ATM-level and performance parameters. Appendix I discusses the performance effects of network indications of congestion and m
39、akes general recommendations for controlling these effects. Appendix II discusses performance effects of excessive demand for connection resources. Appendix III gives a method of estimating the FLR from network statistics. ITU-T Rec. X.144 (10/2003) 3 X.144_F01(Frame relaynetwork)DSEDSENetwork secti
40、onDTEorDSECircuit sectionDTEorDSEFrame transfer reference eventsClause 4/X.144FunctionAccess(call set-up)UserinformationtransferDisengagement(call tear-down)Speed DependabilityAccuracyClause 5/X.144CriterionServiceavailable(No outage)Frame relayavailabilityServiceavailable(Outage)ITU-T Rec. X.147Phy
41、sicalinterfacePhysicalinterfacePhysicalinterfacePhysicalinterfaceClause 5/X.145Clause 5/X.145Figure 1/X.144 Scope of ITU-T Rec. X.144 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommen
42、dation. 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 and other reference
43、s 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. ITU-T Recommendation I.356 (2000), B-ISDN ATM layer cell transfer performanc
44、e. ITU-T Recommendation I.363 (1993), B-ISDN ATM adaptation layer (AAL) specification. ITU-T Recommendation I.365.1 (1993), B-ISDN ATM adaptation layer sublayers: Frame relaying service specific convergence sublayer (FR-SSCS). ITU-T Recommendation I.370 (1991), Congestion management for the ISDN fra
45、me relaying bearer service. 4 ITU-T Rec. X.144 (10/2003) ITU-T Recommendation I.555 (1997), Frame Relaying Bearer Service interworking. ITU-T Recommendation X.36 (2003), Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for public data networks providing fr
46、ame relay data transmission service by dedicated circuit. ITU-T Recommendation X.76 (2003), Network-to-network interface between public networks providing PVC and/or SVC frame relay data transmission service. ITU-T Recommendation X.140 (1992), General quality of service parameters for communication
47、via public data networks. ITU-T Recommendation X.145 (2003), Connection establishment and disengagement performance parameters for public Frame Relay data networks providing SVC services. ITU-T Recommendation X.146 (2000), Performance objectives and quality of service classes applicable to frame rel
48、ay. ITU-T Recommendation X.147 (2003), Frame Relay network availability. ITU-T Recommendation X.148 (2003), Procedures for the measurement of performance of public data networks providing the international frame relay service. ITU-T Recommendation X.329 (2000), General arrangements for interworking
49、between networks providing frame relay data transmission services and B-ISDN. 3 Abbreviations This Recommendation uses the following abbreviations: ACS Access Circuit Section ANS Access Network Section BcCommitted Burst Size BCTDR Bit-based Conformant Traffic Distortion Ratio BeExcess Burst Size BECN Backward Explicit Congestion Notification BLR Bit Loss Ratio CIR Committed Information Rate CLLM Consolidated Link Layer Management DE Discard Eligible DLCI Data Link Connection
