1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T X.148 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2003) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS Public data networks Network aspects Procedures for the measurement of the performance of public data networks providing the internation
2、al frame relay service ITU-T Recommendation X.148 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 Admi
3、nistrative arrangements X.180X.199 OPEN 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
4、 Protocols X.270X.279 Layer Managed Objects 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 ASPECT
5、S Networking X.600X.629 Efficiency X.630X.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
6、Structure of Management Information X.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 det
7、ails, please refer to the list of ITU-T Recommendations. ITU-T Rec. X.148 (02/2003) i ITU-T Recommendation X.148 Procedures for the measurement of the performance of public data networks providing the international frame relay service Summary This Recommendation defines procedures for the measuremen
8、t and assessment of the user information transfer performance parameters of Frame Relay virtual connections. Use is made of OAM Frames and methods for measuring Frame Transit Delay, Frame Delay Jitter and Frame Loss Ratio are specified. The techniques are applicable to both PVCs and SVCs. The techni
9、ques defined enable in-service real time performance estimation. Source ITU-T Recommendation X.148 (2003) was prepared by ITU-T Study Group 17 (2001-2004) and approved under the WTSA Resolution 1 procedure on 13 February 2003. ii ITU-T Rec. X.148 (02/2003) FOREWORD The International Telecommunicatio
10、n 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 view
11、 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 Recommendati
12、ons 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 concisene
13、ss to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL 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
14、 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, ITU had not received notice of intellectual property, protected
15、 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. ITU 2003 All rights reserved. No part of this publication may be reproduced
16、, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. X.148 (02/2003) iii CONTENTS Page 1 Scope. 1 1.1 General . 1 1.2 Parameters to be measured . 1 1.3 Accuracy requirements of measurements. 2 2 References. 4 3 Definitions 4 4 Abbreviations 4 5 Measurement Methodologies
17、 5 5.1 Use of test traffic to estimate performance parameters 6 5.2 Use of OAM Frames to estimate performance. 6 6 Use of FRF.19 OAM Frames to measure the Frame Relay performance parameters 7 6.1 Measurement duration, frequency and sampling rates . 7 6.2 OAM frame format. 8 6.3 Network initialisatio
18、n and awareness of OAM capabilities within a network . 8 6.4 Measurement of frame loss in both directions . 8 7 Procedures to estimate frame transfer delay. 8 7.1 Measurement procedure description. 8 7.2 Delay measurement initiation. 9 7.3 Transfer delay information frame turnaround 9 7.4 Calculatio
19、n of frame transfer delay 9 7.5 Delivery of delay results. 10 7.6 Error handling. 10 8 Procedures for the estimation of frame delay jitter 10 9 Procedures for estimation of frame loss ratio/frame delivered ratio 10 9.1 Procedures for frame delivery ratio measurement 10 9.2 Frame delivery ratio initi
20、ation 11 9.3 Frame delivery ratio measurement . 11 9.4 Delivery of frame delivery ratio results 13 9.5 FDR error handling. 13 10 Procedures for data delivery ratio measurement 13 10.1 Data delivery ratio initiation. 13 10.2 Data delivery ratio measurement 14 10.3 Delivery of data delivery ratio resu
21、lts 14 iv ITU-T Rec. X.148 (02/2003) Page 10.4 DDR error handling 14 11 Frame relay service availability estimation procedures 15 Annex A Measurement architectures applicable to the use of test traffic for the estimation of performance 15 A.1 General considerations and measurement methodologies 15 A
22、.2 Frame relay performance parameters and measurement architectures. 17 A.3 Loopbacks. 18 Annex B OAM message formats 20 B.1 Basic FR-OAM frame structure . 20 B.2 Frame transfer delay information field. 20 B.3 Frame transfer delay results information field . 21 B.4 Frame delivery ratio sync informat
23、ion field. 21 B.5 Frame delivery ratio results information field 21 Appendix I OAM message flows 22 I.1 Use of Hello messages for network discovery . 22 I.2 FTD measurement 23 I.3 FDR/DDR measurement 24 Appendix II Example of frame delivery ratio (loss) calculations. 25 II.1 Ingress processing 25 II
24、.2 Egress processing . 26 ITU-T Rec. X.148 (02/2003) 1 ITU-T Recommendation X.148 Procedures for the measurement of the performance of public data networks providing the international frame relay service 1 Scope This Recommendation describes a methodology for measuring, in near real time, the perfor
25、mance parameters of virtual connections established over public frame relay data networks. The preferred measurement procedures are based on the use of FR-OAM Frames as defined by FRF.19. Clause 5 provides a general overview of the measurement methodologies that may be used to measure the Quality of
26、 Service parameters. The use of test traffic, and the associated measurement architectures, is based on methods specified in ITU-T Rec. X.l38. Clauses 6 through 10 present estimation procedures for frame transfer delay, frame delay jitter, frame loss ratio (derived from frame delivery ratio), and da
27、ta delivery ratio based on the use of OAM Frames. Methods for estimating service availability are for further study. Annex A provides information on the use of test traffic in conjunction with dedicated monitoring equipment. Note that other measurement devices and procedures that adhere to the perfo
28、rmance parameter definitions in ITU-T Recs X.144, X.145 and X.146 are also acceptable for estimating the performance of frame relay public data networks. 1.1 General The network performance of Frame Relay networks may need to be measured for the following reasons: network performance objectives may
29、be included in service level agreements or other contractual arrangements; ongoing measurement/assessment of network performance as part of operational procedures; to assist network planning: collection of data for network dimensioning purposes; network operators may require ongoing knowledge of the
30、ir networks capabilities as defined by the primary performance parameters; Quality of Service parameters may need to be measured for use in other Recommendations; National Regulatory Requirements 1.2 Parameters to be measured ITU-T Recs X.144 and X.145 define performance parameters which specify the
31、 Quality of Service of a Frame Relay virtual connection. ITU-T Rec. X.146 defines various QoS classes. The QoS classes are characterized by distinct combinations of objective values for the following primary performance parameters: Frame Transfer Delay (FTD); Frame Delay Jitter (FDJ); Frame Loss Rat
32、io (FLR) (derived from Frame Delivery Ratio). These primary parameters, when taken together with the derived parameter of service or network availability, define the overall quality of the data transfer phase of a frame relay connection. The measurement techniques defined in this Recommendation are
33、applicable to both PVCs and SVCs since in both cases measurement of the performance parameters is related to the data transfer phase of a FR connection. 2 ITU-T Rec. X.148 (02/2003) 1.3 Accuracy requirements of measurements 1.3.1 Measurement objectives In measuring network performance, there is alwa
34、ys a cost versus sample size tradeoff which must be resolved when attempting to estimate a given performance parameter. As the cost of taking an observation can have a considerable effect on the final estimate achieved, this Recommendation does not recommend a minimum number of observations. However
35、, a sufficient number of measurements must be made in order to obtain statistical significance. Additionally, in certain situations, estimating the parameter with a high level of precision may not be required. For example, estimating Frame Transfer Delay to within between 2 ms may be adequate for mo
36、st planning and monitoring purposes. Estimates of means, variances, percentile, modes, maxima and minima are all examples of statistical descriptors which may be used to quantify the performance achieved by a specific parameter. In reporting any such estimated parameters, it is always recommended th
37、at a measure of the precision of the estimate be included. The variance of the estimate, or a confidence interval about the estimate, are two common methods of expressing the estimates precision. 1.3.2 Reference events The time of occurrence of various reference events is the basis for the definitio
38、ns of the speed of service parameters (i.e, FTD and FDJ) listed above. In this Recommendation, times are specified with respect to exit and entry events relative to the test equipment. Thus, the time of occurrence of an entry event into such a DTE is the time at which the last bit of the closing fla
39、g of the frame enters the DTE from a circuit section, and the time of occurrence of an exit event from such a DTE is the time at which the first bit of the address field of the frame enters the circuit section from the DTE. The exact definition of a Frame Reference Event for the user information tra
40、nsfer parameters is given in ITU-T Rec. X.144. ITU-T Rec. X.148 (02/2003) 3 X.148_F01DSE DSENetwork section Circuit sectionFrame transfer reference eventsFunctionAccessDisengagementSpeed DependabilityAccuracyCriterionX.144Parameters defined in X.145Parameters defined in X.145PhysicalinterfacePhysica
41、linterfacePhysicalinterface(Frame relaynetwork)DTEorDSEPhysicalinterfaceDTEorDSEParameters defined in X.144 and X.146Measurement Methods defined inClauses 6 to 10/X.148UserinformationtransferServiceavailable(no outage)ServiceUnavailable(outage)AvailabilityParameters definedX.144 and X.145Measurement
42、 Methods(for further study)Figure 1/X.148 Scope of ITU-T Rec. X.148 4 ITU-T Rec. X.148 (02/2003) 2 References The following ITU-T Recommendations and other references contain provisions, which, through reference in this text, constitute provisions of this Recommendation. At the time of publication,
43、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 references listed below. A list of the curren
44、tly 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 G.114 (2003), One-way transmission time. ITU-T Recommendation I.610 (1999), B-ISDN operatio
45、n and maintenance principles and functions. ITU-T Recommendation I.620 (1996), Frame relay operation and maintenance principles and functions. ITU-T Recommendation X.36 (2003), Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for public data networks provi
46、ding frame 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.138 (1997), Measurement of performance values for public data
47、 networks when providing international packet-switched services. ITU-T Recommendation X.139 (1997), Echo, drop, generator and test DTEs for measurement of performance values in public data networks when providing international packet-switched services. ITU-T Recommendation X.140 (1992), General qual
48、ity of service parameters for communication via public data networks. ITU-T Recommendation X.144 (2000), User information transfer performance parameters for data networks providing international frame relay PVC service. ITU-T Recommendation X.145 (1996), Performance for data networks providing inte
49、rnational frame relay SVC service. ITU-T Recommendation X.146 (2000), Performance objectives and quality of service classes applicable to frame relay. Frame Relay Forum Implementation Agreement 19, FRF.19 (2001), Frame Relay Operations, Administration, and Maintenance Implementation Agreement. 3 Definitions The terms and definitions used in this Recommendation are consistent with those defined in ITU-T Recs X.36, X.76, X.138, X.139, X.144, X.145, X.146, I.620, I.610 and Frame Relay Forum Implementation Agreement FRF.19.
