1、 International Telecommunication Union ITU-T O.182TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2007) SERIES O: SPECIFICATIONS OF MEASURING EQUIPMENT Equipment for the measurement of digital and analogue/digital parameters Equipment to assess error performance on Optical Transport Network inte
2、rfaces ITU-T Recommendation O.182 ITU-T O-SERIES RECOMMENDATIONS SPECIFICATIONS OF MEASURING EQUIPMENT General O.1O.9 Maintenance access O.10O.19 Automatic and semi-automatic measuring systems O.20O.39 Equipment for the measurement of analogue parameters O.40O.129 Equipment for the measurement of di
3、gital and analogue/digital parameters O.130O.199 Equipment for the measurement of optical channel parameters O.200O.209 Equipment to perform measurements on IP networks O.210O.219 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. O.182 (07/2007) i ITU-T Recommendatio
4、n O.182 Equipment to assess error performance on Optical Transport Network interfaces Summary ITU-T Recommendation O.182 specifies measuring equipment for monitoring defects and anomalies and for measuring error performance and forward error correction (FEC) efficiency at the OCh layer of the optica
5、l transport network (OTN). Source ITU-T Recommendation O.182 was approved on 22 July 2007 by ITU-T Study Group 4 (2005-2008) under the ITU-T Recommendation A.8 procedure. Keywords Error performance, Forward Error Correction, In-service, Measuring equipment, Measurement mode, Optical Transport Networ
6、k, Out-of-service, Test Signal Structure. ii ITU-T Rec. O.182 (07/2007) FOREWORD The International Telecommunication 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
7、 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 Assembly (WTSA), which meets every four years, establishes the topics for study by
8、 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 WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a colla
9、borative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certa
10、in mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation 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 requiremen
11、ts. The use of such words does not suggest that compliance with the Recommendation is required of any party. 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. IT
12、U takes no position 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 received notice of intellectual prop
13、erty, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2008 All rights reserved
14、. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. O.182 (07/2007) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation. 2 4 Abbreviations and
15、acronyms 3 5 Conventions and background . 5 5.1 Conventions 5 5.2 Background. 5 6 Measurement modes . 6 7 Events to be monitored . 6 7.1 Network events. 7 7.2 Test signal structure events 8 7.3 Forward error correction (FEC) events 8 7.4 Events to be monitored at the OCh layer 8 7.5 Test signal stru
16、cture to be used at OPUk layer. 9 8 Generator 10 8.1 Synchronization 10 8.2 Bit rates. 10 8.3 Test signal structures 10 8.4 Digital signal outputs 10 8.5 Anomaly and defect addition on the output signal. 10 9 Receiver 10 9.1 Digital signal inputs 10 9.2 Test signal structures 11 9.3 Error performanc
17、e measurement 11 9.4 Defects and anomalies indication. 13 9.5 Events time stamping . 13 10 Forward error correction (FEC) performance verification functions . 13 10.1 Parameters and results 13 10.2 Error generation 14 10.3 Measurement of the error correction and detection 14 11 Miscellaneous functio
18、ns . 16 11.1 FEC activation 16 11.2 Display 16 11.3 Access to overhead bytes 16 iv ITU-T Rec. O.182 (07/2007) Page 11.4 Output to external recording devices 16 11.5 Remote control port 16 12 Operating conditions. 16 12.1 Environmental conditions. 16 12.2 Behaviour in case of power failure. 16 Annex
19、A Criteria for detecting anomalies and defects . 17 A.1 Anomalies. 17 A.2 Defects 18 A.3 Other information . 19 Annex B List of test signal structures . 21 B.1 Test signal structure TSS1 applied to all bytes of a CBR2G5 . 21 B.2 Test signal structure TSS2 applied to all bytes of a CBR10G . 21 B.3 Te
20、st signal structure TSS3 applied to all bytes of a CBR40G . 22 B.4 Test signal structure TSS4 applied to NULL/PRBS 22 Annex C Procedure of goodness of fit for Poisson distribution by 2test 24 C.1 Introduction 24 C.2 Fundamental properties 24 C.3 Other properties 24 Appendix I Test of goodness of fit
21、 for Poisson distribution by 2test . 27 I.1 Introduction 27 I.2 Test of goodness of fit by 2test 27 I.3 Theory of 2test 28 I.4 Application of test of goodness of fit to Poisson distribution 30 Bibliography. 38 ITU-T Rec. O.182 (07/2007) 1 ITU-T Recommendation O.182 Equipment to assess error performa
22、nce on Optical Transport Network interfaces 1 Scope This Recommendation specifies the functions of measuring equipment which has the capability of assessing OCh layer (OTUk, ODUk, OPUk) frame-error performance at OTN interfaces. ITU-T G.959.1 defines the OTN physical interface characteristics. ITU-T
23、 G.709 defines the OTN signals applicable to these measurements. Depending on the network entity under test, this Recommendation specifies the use of either in-service or out-of-service measurement modes. Annex A of ITU-T G.709 specifies FEC for OTUk frame. This Recommendation defines the functions
24、of Forward Error Correction (FEC) performance verification. Furthermore, this Recommendation defines the required functions of the generator and receiver part of the error performance measuring equipment. This Recommendation does not cover OTUkV framing. 2 References The following ITU-T Recommendati
25、ons and other references contain provisions which, through reference in this text, constitute provisions 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
26、 encouraged to investigate the possibility of applying the most recent edition of the Recommendations and 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-alo
27、ne document, the status of a Recommendation. ITU-T G.707 ITU-T Recommendation G.707/Y.1322 (2007), Network node interface for the synchronous digital hierarchy (SDH). ITU-T G.709 ITU-T Recommendation G.709/Y.1331 (2003), Interfaces for the Optical Transport Network (OTN). ITU-T G.798 ITU-T Recommend
28、ation G.798 (2006), Characteristics of optical transport network hierarchy equipment functional blocks. ITU-T G.806 ITU-T Recommendation G.806 (2006), Characteristics of transport equipment Description methodology and generic functionality. ITU-T G.870 ITU-T Recommendation G.870/Y.1352 (2004), Terms
29、 and definitions for optical transport networks (OTN). ITU-T G.872 ITU-T Recommendation G.872 (2001), Architecture of optical transport networks. ITU-T G.959.1 ITU-T Recommendation G.959.1 (2006), Optical transport network physical layer interfaces. ITU-T G.972 ITU-T Recommendation G.972 (2004), Def
30、inition of terms relevant to optical fibre submarine cable systems. ITU-T G.975.1 ITU-T Recommendation G.975.1 (2004), Forward error correction for high bit-rate DWDM submarine systems. 2 ITU-T Rec. O.182 (07/2007) ITU-T G.8201 ITU-T Recommendation G.8201 (2003), Error performance parameters and obj
31、ectives for multi-operator international paths within the Optical Transport Network (OTN). ITU-T G.8251 ITU-T Recommendation G.8251 (2001), The control of jitter and wander within the optical transport network (OTN). ITU-T M.2401 ITU-T Recommendation M.2401 (2003), Error performance limits and proce
32、dures for bringing-into-service and maintenance of multi-operator international paths and sections within an optical transport network. ITU-T O.3 ITU-T Recommendation O.3 (1992), Climatic conditions and relevant tests for measuring equipment. ITU-T O.150 ITU-T Recommendation O.150 (1996), General re
33、quirements for instrumentation for performance measurements on digital transmission equipment. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 optical transport network (OTN): See ITU-T G.872 3.1.2 forward error correction (FEC): See IT
34、U-T G.972 3.1.3 CBR2G5, CBR10G, CBR40G: See ITU-T G.709 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 black box testing: Black box testing does not explicitly use the knowledge of the internal implementation. 3.2.2 in-service measurement modes: The d
35、igital signal transported by the entity under test (EUT) is analysed at a given access point of the EUT. 3.2.3 out-of-service measurement modes: After setting up a path through the entity under test (EUT) by appropriate means, a suitable test sequence is applied to the input at one side of the EUT.
36、The received information is analysed at an access point at the other side of the EUT. 3.2.4 test signal structure (TSS): A test signal structure specifies the mapping of a defined test pattern onto an OPUk. 3.2.5 white box testing: White box testing allows one to peek inside the “box“ (the actual EU
37、T) and to use the knowledge of the internal implementation of the EUT. Out-of-service measurement is performed in absence of user traffic. Consequently, the test signal to be used in case of out-of-service mode must be defined. Annex B defines the test signal structure named TSSx (x being a number)
38、to be used. ITU-T Rec. O.182 (07/2007) 3 Table 3-1 presents the four test signal structures. They are detailed in Annex B. Table 3-1 Test signal structures TSS1 Test signal structure TSS1 applied to all bytes of a CBR2G5 TSS2 Test signal structure TSS2 applied to all bytes of a CBR10G TSS3 Test sign
39、al structure TSS3 applied to all bytes of a CBR40G TSS4 Test signal structure TSS4 applied to NULL/PRBS 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AIS Alarm Indication Signal BBE Background Block Error BBER Background Block Error Ratio BDI Backwar
40、d Defect Indicator BEI Backward Error Indicator BIAE Backward Incoming Alignment Error BIP-8 Bit Interleaved Parity CBR Constant Bit Rate CBR2G5 Constant Bit Rate of 2.5 Gigabits CBR10G Constant Bit Rate of 10 Gigabits CBR40G Constant Bit Rate of 40 Gigabits EB Errored Block EDC Error Detection Code
41、 EUT Entity Under Test FA Frame Alignment FEC Forward Error Correction FUEB FEC Uncorrected Error Blocks GCC General Communication Channel IAE Incoming Alignment Error JC Justification Control LCK Locked Defect LOF Loss of Frame LOM Loss of Multiframe LOS Loss Of Signal LSS Loss of Sequence Synchron
42、ization LTC Loss of Tandem Connection ME Measuring Equipment NJO Negative Justification Opportunity 4 ITU-T Rec. O.182 (07/2007) OCh Optical Channel with full functionality OCI Open Connection Indication ODTUjk Optical channel Data Tributary Unit j into k ODU Optical channel Data Unit ODUk Optical c
43、hannel Data Unit-k OH OverHead ONNI Optical Network Node Interface OOF Out Of Frame OOM Out of Multiframe OPU Optical channel Payload Unit OPUk Optical channel Payload Unit-k OTN Optical Transport Network OTUk Optical channel Transport Unit -k PJO Positive Justification Opportunity PLM Payload Misma
44、tch PM Path Monitoring PRBS Pseudo Random Binary Sequence PSI Payload Structure Identifier PT Payload Type RES Reserved for future international standardization RS Reed-Solomon SES Severely Errored Second SESR Severely Errored Second Ratio SM Section Monitoring STM(-N) Synchronous Transport Module (
45、-N) TC Tandem Connection TCM Tandem Connection Monitoring TCMi Tandem Connection Monitoring i (i = 1,2,.,6) TIM Tail trace Identifier Mismatch TSE Test Sequence Error TSS Test Signal Structure VC-n Virtual Container-n ITU-T Rec. O.182 (07/2007) 5 5 Conventions and background 5.1 Conventions The foll
46、owing conventions are directly taken from ITU-T G.709: Transmission order: The order of transmission of information in all the diagrams in this Recommendation is first from left to right and then from top to bottom. Within each byte the most significant bit is transmitted first. The most significant
47、 bit (bit 1) is illustrated at the left in all the diagrams. Value of reserved bit(s): The value of an overhead bit, which is reserved or reserved for future international standardization, shall be set to “0“. Value of non-sourced bit(s): Unless stated otherwise, any non-sourced bits shall be set to
48、 “0“. 5.2 Background The following figures illustrate OTN framing. They are directly taken from ITU-T G.709: OTUk, ODUk and OPUk overhead assignment: The assignment of overhead in the optical channel transport/data/payload unit signal to each part is defined in Figure 5-1. Figure 5-1 OTUk, ODUk and
49、OPUk overhead (taken from ITU-T G.709) OTUk, ODUk and OPUk frame structure: The frame structures in the optical channel transport/data/payload unit signal are defined in Figures 5-2, 5-3 and 5-4. Figure 5-2 OTUk frame structure (taken from ITU-T G.709) 6 ITU-T Rec. O.182 (07/2007) Figure 5-3 ODUk frame structure (taken from ITU-T G.709) Figure 5-4 OPUk frame structure (taken from ITU-T G.709) 6 Measurement modes Two measurement modes shall be supported by OTN measurement equipment: 1) Out-of-service measurement mo
