1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T G.829TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (12/2002) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital networks Quality and availability targets Error performance events for SDH multiplex and regenerator sections ITU
2、-T Recommendation G.829 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNA
3、TIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TESTING EQUIPMENTS G.500G
4、.599 TRANSMISSION MEDIA CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 General aspects G.800G.809 Design objectives for digital networks G.810G.819 Quality and availability targets G.820G.829 Network capabilities and functions G.830G.839 SDH network cha
5、racteristics G.840G.849 Management of transport network G.850G.859 SDH radio and satellite systems integration G.860G.869 Optical transport networks G.870G.879 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 QUALITY OF SERVICE AND PERFORMANCE G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.600
6、0G.6999 DIGITAL TERMINAL EQUIPMENTS G.7000G.7999 DIGITAL NETWORKS G.8000G.8999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.829 (12/2002) i ITU-T Recommendation G.829 Error performance events for SDH multiplex and regenerator sections Summary ITU-T Rec. G.828
7、6 specifies error performance parameters and objectives of international, constant bit rate synchronous digital paths. Error performance objectives of ITU-T Rec. G.828 refer to the hypothetical reference path (HRP) of a length of 27 500 km. ITU-T Rec. G.828 does not contain information on path eleme
8、nts. NOTE Performance objectives for SDH paths using equipment designed prior to the adoption of ITU-T Rec. G.828 in March 2000 are given in ITU-T Rec. G.826 5. This Recommendation defines error performance events and block structures for SDH multiplex and regenerator sections (see ITU-T Recs G.707/
9、Y.1322 1 and G.708 2 for reference). SDH equipment functional blocks and SDH management are defined in ITU-T Recs G.783 3 and G.784 4. Observing the definitions given in this Recommendation shall ensure that error performance assessment on SDH multiplex and regenerator sections yields compatible res
10、ults. Definition of events in this Recommendation is based on the same basic concept as in ITU-T Rec. G.828 6. The events defined for regenerator sections apply to microwave radio and satellite systems only. Performance monitoring of SDH sections is not mandatory. If implemented, the specifications
11、of this Recommendation apply. Source ITU-T Recommendation G.829 was revised by ITU-T Study Group 13 (2001-2004) and approved under the WTSA Resolution 1 procedure on 14 December 2002. Keywords Background Block Error, Block-based measurement concept, Error Detection Code (EDC), Error performance even
12、ts, Errored Second (ES), In-Service Monitoring (ISM), SDH multiplex section, SDH regenerator section, SES threshold, Severely Errored Second (SES), Synchronous Digital Hierarchy (SDH). ii ITU-T Rec. G.829 (12/2002) FOREWORD The International Telecommunication Union (ITU) is the United Nations specia
13、lized 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 standardizing telecommunications on a
14、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 covered by the procedure laid down
15、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 indicate both a telecommunication ad
16、ministration 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 concerning the evidence, validity or appl
17、icability 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 by patents, which may be required to impl
18、ement 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, by any means whatsoever, without the pri
19、or written permission of ITU. ITU-T Rec. G.829 (12/2002) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Abbreviations 2 4 The definition and measurement of the block for SDH multiplex sections . 2 4.1 Definition of the block for an SDH multiplex section . 2 4.2 Block sizes 3 4.2.1 In-service monitori
20、ng of blocks 3 4.3 Out-of-service measurements of blocks . 3 5 Error performance events for SDH multiplex sections. 4 5.1 Definitions 4 5.2 Events determination for multiplex sections 4 5.2.1 Anomalies. 4 5.2.2 Defects 4 5.2.3 Estimation of the performance events 4 6 The definition and measurement o
21、f the block for SDH regenerator sections. 5 6.1 Definition of the block for an SDH regenerator section. 5 6.2 Block sizes 5 6.3 In-service monitoring of blocks 6 6.4 Out-of-service measurements of blocks . 6 7 Error performance events for SDH regenerator sections 6 7.1 Definitions 6 7.2 Events deter
22、mination for regenerator sections . 7 7.2.1 Anomalies. 7 7.2.2 Defects 7 7.2.3 Estimation of the performance events 7 Annex A Entry and exit criteria for the unavailable state of a single direction of an SDH section 8 A.1 Criteria for a single direction 8 ITU-T Rec. G.829 (12/2002) 1 ITU-T Recommend
23、ation G.829 Error performance events for SDH multiplex and regenerator sections 1 Scope This Recommendation is applicable to multiplex and regenerator sections employing Synchronous Digital Hierarchy (SDH) technology. This Recommendation is generic in that it defines the events for multiplex section
24、s independent of the physical transport medium supporting the sections. The performance events are applicable to each kind of multiplex section, based on optical fibre, digital radio relay, metallic cable and satellite transmission systems or on a combination of them. The events defined for regenera
25、tor sections apply to microwave radio and satellite systems only. In accordance with ITU-T Rec. G.828 6, the event definitions are block-based, making in-service error evaluation convenient. Out-of-service measurements shall be based on the same principles. This Recommendation does not address error
26、 performance objectives and allocations. Performance limits for bringing-into-service and maintenance of international SDH multiplex and regenerator sections can be found in ITU-T Rec. M.2101 7. This Recommendation only specifies the unavailability of a single direction of a section, but not the una
27、vailability of a section as such. This concept is different to the one used in ITU-T Rec. G.828 6 which contains a specification for the unavailability of a path taking into account both directions of that path (see Annex A). 2 References The following ITU-T Recommendations and other references cont
28、ain 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 encouraged to investigate th
29、e 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-alone document, the status of a
30、Recommendation. 1 ITU-T Recommendation G.707/Y.1322 (2000), Network node interface for the synchronous digital hierarchy (SDH), plus Corrigendum 1 (2001), Corrigendum 2 (2001) and Amendment 1 (2001). 2 ITU-T Recommendation G.708 (1999), Sub STM-0 network node interface for the synchronous digital hi
31、erarchy (SDH). 3 ITU-T Recommendation G.783 (2000), Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks, plus Corrigendum 1 (2001). 4 ITU-T Recommendation G.784 (1999), Synchronous digital hierarchy (SDH) management. 5 ITU-T Recommendation G.826 (2002), End-to-end erro
32、r performance parameters and objectives for international, constant bit-rate digital paths and connections. 6 ITU-T Recommendation G.828 (2000), Error performance parameters and objectives for international, constant bit-rate synchronous digital paths, plus Corrigendum 1 (2001). 7 ITU-T Recommendati
33、on M.2101 (2000), Performance limits and objectives for bringing-into-service and maintenance of international SDH paths and multiplex sections. 2 ITU-T Rec. G.829 (12/2002) 8 ITU-T Recommendation M.2101.1 (1997), Performance limits for bringing-into-service and maintenance of international SDH path
34、s and multiplex sections. 3 Abbreviations This Recommendation uses the following abbreviations: AIS Alarm Indication Signal BBE Background Block Error BIP Bit Interleaved Parity EB Errored Block EDC Error Detection Code ES Errored Second HRP Hypothetical Reference Path ISM In-Service Monitoring LOF
35、Loss of Frame Alignment LOS Loss of Signal OOS Out-of-Service RDI Remote Defect Indication REI Remote Error Indication RS-TIM Regenerator Section Trace Identifier Mismatch SDH Synchronous Digital Hierarchy SES Severely Errored Second STM Synchronous Transport Module 4 The definition and measurement
36、of the block for SDH multiplex sections 4.1 Definition of the block for an SDH multiplex section In accordance with ITU-T Rec. G.828 6, this Recommendation is based upon the error performance measurement of blocks. This clause gives definitions of the term “block“ as follows: 4.1.1 generic definitio
37、n: A block is a set of consecutive bits associated with the section; each bit belongs to one and only one block. “Consecutive“ bits may not be contiguous in time. 4.1.2 block definition applicable to sub-STM-0 bit rates: The 8 BIP-1s contained in the B2 byte of an SDH multiplex section in an sSTM-2n
38、 (n = 1, 2, 4) and sSTM-1k (k = 1, 2, 4, 8, 16) pertain to 8 different blocks. Thus, the signal structure of a generic multiplex section in an sSTM-2n and sSTM-1k comprises 8 blocks within a 125 s frame. The generic i-th block (1 i 8) is equivalent to the i-th bit of the B2 byte and the correspondin
39、g monitored bits in the same frame as defined in ITU-T Rec. G.708 2. 4.1.3 block definition applicable to STM-0: The 8 BIP-1s contained in the B2 byte of an SDH multiplex section in an STM-0 pertain to 8 different blocks. Thus, the signal structure of a generic multiplex section in an STM-0 comprise
40、s 8 blocks within a 125 s frame. The generic i-th block (1 i 8) is equivalent to the i-th bit of the B2 byte and the corresponding monitored bits in the same frame as defined in ITU-T Rec. G.707/Y.1322 1. ITU-T Rec. G.829 (12/2002) 3 4.1.4 block definition applicable to STM-N (N = 1, 4, 16, 64): The
41、 N 24 BIP-1s contained in the B2 bytes of an SDH multiplex section in an STM-N (N = 1, 4, 16, 64) pertain to N 24 different blocks. Thus, the signal structure of a generic multiplex section in an STM-N comprises N 24 blocks within a 125 s frame. The generic i-th block (1 i N 24) is equivalent to the
42、 i-th bit of the B2 bytes and the corresponding monitored bits in the same frame as defined in ITU-T Rec. G.707/Y.1322 1. 4.2 Block sizes Table 1 defines, for each type of multiplex section, the block size (number of bits per block), the number of blocks per second (blocks/s), the associated error d
43、etection code (EDC) and the blocks per frame. Table 1/G.829 Block sizes, blocks per frame, blocks per second and EDCs for SDH multiplex sections STM-N Block size Blocks per frame Blocks per second EDC sSTM-1k (Note 2) k 36 bits (Notes 2 and 4) 8 64 000 (Note 5) 8 BIP-1 sSTM-2n (Note 1) n 108 bits (N
44、otes 1 and 3) 8 64 000 (Note 5) 8 BIP-1 STM-0 801 bits 8 64 000 (Note 5) 8 BIP-1 STM-1 801 bits 24 192 000 (Note 5) 24 BIP-1 STM-4 801 bits 96 768 000 (Note 5) 96 BIP-1 STM-16 801 bits 384 3 072 000 (Note 5) 384 BIP-1 STM-64 801 bits 1536 12 288 000 (Note 5) 1536 BIP-1 NOTE 1 n = 1, 2 and 4 accordin
45、g to ITU-T Rec. G.708 2. NOTE 2 k = 1, 2, 4, 8, 16 according to ITU-T Rec. G.708 2. NOTE 3 Bits per frame composed by payload bytes 864 n. The SOH bytes are excluded. NOTE 4 Bits per frame composed by payload bytes 288 k. The SOH bytes are excluded. NOTE 5 Blocks per second = Blocks per frame 8000.
46、4.2.1 In-service monitoring of blocks Each block is monitored by means of an inherent Error Detection Code, e.g. Bit Interleaved Parity. The EDC bits are physically separated from the block to which they apply. It is not normally possible to determine whether a block or its controlling EDC bits are
47、in error. If there is a discrepancy between the EDC and its controlled block, it is always assumed that the controlled block is in error. 4.3 Out-of-service measurements of blocks Out-of-service (OOS) measurements shall also be block-based and shall make use of the same blocks as defined for in-serv
48、ice monitoring (ISM). This will allow an easy comparison of OOS measurements and ISM. It is expected that the out-of-service error detection capability will be superior to the in-service capability described in 4.2.1. 4 ITU-T Rec. G.829 (12/2002) 5 Error performance events for SDH multiplex sections
49、 5.1 Definitions 5.1.1 errored block (EB): A block in which one or more bits are in error. 5.1.2 errored second (ES): A one-second period with one or more errored blocks or at least one defect (see Note 1). 5.1.3 severely errored second (SES): A one-second period which contains X% errored blocks or at least one defect. SES is a subset of ES (see Notes 1 and 2). NOTE 1 The anomalies, defects and related performance criteria are listed in 5.2.1 and 5.2.2.
