1、 International Telecommunication Union ITU-T G.7710/Y.1701TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(07/2010) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Data over Transport Generic aspects Transport network control aspects SERIES Y: GLOBAL INFORMATION INF
2、RASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects Operation, administration and maintenance Common equipment management function requirements Amendment 1: Required specification of severely errored second to align with Recommendation ITU-T Y.1563 Recommend
3、ation ITU-T G.7710/Y.1701 (2007) Amendment 1 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 CHARA
4、CTERISTICS OF INTERNATIONAL 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 TRAN
5、SMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTE
6、RISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 General G.7000G.7099 Transport network control aspects G.7700G.7799PACKET OVER TRANSPORT ASPECTS G.8000G.89ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.7710/Y.17
7、01 (2007)/Amd.1 (07/2010) i Recommendation ITU-T G.7710/Y.1701 Common equipment management function requirements Amendment 1 Required specification of severely errored second to align with Recommendation ITU-T Y.1563 Summary Amendment 1 to Recommendation ITU-T G.7710/Y.1701 updates the packet layer
8、related specification of severely errored second (SES) in Recommendation ITU-T G.7710/Y.1701 to align it with the SES definition in Recommendation ITU-T Y.1563. History Edition Recommendation Approval Study Group 1.0 ITU-T G.7710/Y.1701 2001-11-29 15 2.0 ITU-T G.7710/Y.1701 2007-07-29 15 2.1 ITU-T G
9、.7710/Y.1701 (2007) Cor.1 2009-11-13 15 2.2 ITU-T G.7710/Y.1701 (2007) Amend. 1 2010-07-29 15 ii Rec. ITU-T G.7710/Y.1701 (2007)/Amd.1 (07/2010) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and commu
10、nication technologies (ICTs). 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 worldwide basis. Th
11、e 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 in WTSA Resolution
12、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 administration and a
13、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 when all of these mandatory provisions are met.
14、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 PROPERTY RIGHTS ITU draws attention to the possibili
15、ty 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 by ITU members or others outside of the Recom
16、mendation 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, implementers are cautioned that this may not represent the latest information
17、 and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.7710/Y.1701 (2007)/Amd.1 (07/2010) iii
18、 CONTENTS Page 1) Scope 1 2) References. 1 3) Clauses to be updated . 1 3.1) Clause 4 1 3.2) Clause 10.1.2 1 3.3) Clause 10.1.3 3 3.4) Clause 10.1.4 4 3.5) Table 26 of clause 10.1.6.1 . 5 3.6) Clause 10.2 . 5 Rec. ITU-T G.7710/Y.1701 (2007)/Amd.1 (07/2010) 1 Recommendation ITU-T G.7710/Y.1701 Common
19、 equipment management function requirements Amendment 1 Required specification of severely errored second to align with Recommendation ITU-T Y.1563 1) Scope This amendment contains the update to the packet layer related specification of severely errored second (SES) in Recommendation ITU-T G.7710/Y.
20、1701 (version 2007). 2) References ITU-T G.7710 Recommendation ITU-T G.7710/Y.1701 (2007), Common equipment management function requirements. 3) Clauses to be updated The following text and clauses are updated as shown by the revision-marked text. 3.1) Clause 4 Add the following abbreviations to cla
21、use 4 (Abbreviations and acronyms): BB Background Block BBC Background Block Count BD Block Delay BDV Block Delay Variation EBR Errored Block Ratio FD Frame Delay FDV Frame Delay Variation FLR Frame Loss Ratio LB Lost Block LBC Lost Block Count LBR Lost Block Ratio LF Lost Frames TBC Transmitted Blo
22、ck Count TBmin Transmitted Blocks minimum TF Transmitted Frames 2 Rec. ITU-T G.7710/Y.1701 (2007)/Amd.1 (07/2010) 3.2) Clause 10.1.2 Update clause 10.1.2 as follows: 10.1.2 Maintenance The fault management supervision and validation processes (see clauses 7.1.1 and 7.1.2) describe an effective metho
23、d to detect and analyse disturbances, and to provide an appropriate indication of the fault condition to maintenance personnel. The described processes, however, are not able to detect and report all causes leading to degraded performance. Maintenance measurements are required to detect additional e
24、rror causes. In order to be able to do preventive maintenance, it is required to perform signal quality trend analysis. When the quality appears degraded, maintenance personnel may be instructed to replace or repair the degraded equipment before a failure is declared. Signal quality trend analysis i
25、s performed on signal quality maintenance measurements at the sink function. For circuit layer: These measurements are based on transmitted block count (TBC), errored block count (EBC), block delay (BD) and calculated errored block ratio (EBR = EBC/TBC), background block count (BBC), background bloc
26、k errors (BBE) and block delay variation (BDV). the validation of the received error detection code (EDC) for digital layers and frame count (FC) or packet count (PC) for packet layers, the calculation of the EDC violations for digital layers and FC or PC violations (i.e., frame or packet loss) and
27、the derived calculated number of errored blocks (EB) and background block errors (BBE). A block in a digital layer is a set of consecutive bits including an error detection code (EDC) associated with the connection; each bit belongs to one, and only one, block. Consecutive bits may not be contiguous
28、 in time. A block in a packet layer is a frame or packet. An errored block (EB) in a digital layer is a block with one or more EDC violations. An EB in a packet layer is an indication of a lost frame or lost packet. A BBE is an EB not occurring as part of a severely errored second (SES, see next das
29、hed item). A background block (BB) is a transmitted block (TB) not occurring as part of an SES. The number of BBEs and BBs is summed over 15-minute and 24-hour intervals, over which the trend analysis is performed. The TBC is a, circuit signal type and bit rate dependent, fixed value. Summary statis
30、tics (such as minimum, average, and maximum) for BD and BDV are derived over 15-minute and 24-hour interval for continuous monitoring. For packet layer: These measurements are based on transmitted block count (TBC), lost block count (LBC), block delay (BD) and the calculated lost block ratio (LBR =
31、LBC/TBC), background block count (BBC), background block error (BBE) and block delay variation (BDV). A block is a non drop eligible frame or packet with a specific priority associated with the connection. An LB is a lost block. A BBE is a LB not occurring as part of a severely errored second (SES,
32、see next dashed item). The number of BBEs is summed over 15-minute and 24-hour intervals, over which the trend analysis is performed. The TBC is a variable value. Summary statistics (such as minimum, average, and maximum) for BD and BDV are derived over 15-minute and 24-hour intervals for continuous
33、 monitoring. In order to locate the source of intermittent error conditions, e.g., short bursts of bit errors or lost frames or packets, it is required to measure these error conditions at various places in the network. These bursts cause a high number of EBR or LBRs, or result in the declaration of
34、 framing defects (e.g., dLOF, dLOP). Fault management is not able to alert maintenance personnel in these cases because the defects do not persist long enough to become a failure. Rec. ITU-T G.7710/Y.1701 (2007)/Amd.1 (07/2010) 3 Severely errored second (SES): The maintenance measurement is based on
35、 the detection of these bursts.: a An SES is declared when, during one second, the number of EBRs or LBR exceeds a threshold, or when a defect is declared. The number of SESs is summed over 15-minute and 24-hour intervals. The analysis of these reports may be an aid to locate the error source. In or
36、der to determine whether the performance level is normal, degraded or unacceptable, it is required to set appropriate performance limits. For example, according to ITU-T M.2101, the degraded and unacceptable performance limits are expressed as threshold values for the number of background block erro
37、rs (BBEs), the number of errored seconds (ESs) and the number of SESs, summed over 15-minute intervals and 24-hour intervals. An ES is declared when, during one second, there are one or more EBs or LBs detected, or when a defect is declared. When a threshold report (see clause 10.1.7) is generated,
38、maintenance personnel may be driven to perform additional network performance analysis. In order to locate the source that causes the generation of jitter and wander, e.g., due to a wrongly selected timing reference source, it is required to measure these error conditions. Jitter and wander can be m
39、easured directly by connecting the appropriate measurement equipment to the interface port. This method, however, may require maintenance personnel being present at the measurement location. An alternative approach, for example, is to measure the positive and negative pointer justification events (P
40、JEs). These events may be an indication of a wrongly applied timing source. The PJEs are summed over 24-hour intervals. The analysis of these reports may be an aid to locate the error source. In order to locate equipment that needs adjustment or retuning, e.g., to limit drift or oscillation, it is r
41、equired to do gauge measurements at or near the equipment. Examples of gauge measurements are the (optical) power level, the gain and the temperature. These gauges are measured periodically. Maintenance personnel may request a snapshot, in which case the current value is made available at the workst
42、ation or craft terminal. The NE keeps a record of the highest value and the lowest value of the gauge over 15-minute and 24-hour measurement intervals. The analysis of these gauge tidemark reports may drive maintenance personnel to readjust the equipment. It must be noted that the previous described
43、 error causes are indeed detected by the indicated maintenance measurements. The reverse, however, is not always true: not every SES indicates a burst error; an increasing number of BBEs does not necessarily indicate degraded equipment; a large amount of PJEs need not be caused by a wrong timing ref
44、erence source. Therefore, care must be taken with the analysis of the performance maintenance reports. 3.3) Clause 10.1.3 Update clause 10.1.3 as follows: 10.1.3 Bringing-into-service Bringing-into-service (BIS) tests should be long-term measurements of new equipment, using a pseudo-random generator
45、 and receiver. However, for practical reasons the measurements may be reduced to a quick measurement and the assessment completed with in-service performance monitoring available in the network element. BIS methods for paths are defined in ITU-T M.2110. The BIS performance objectives for equipment s
46、upporting digital circuit layers, e.g., SDH Paths, PDH Paths, OTN ODU paths, etc. are based on the collection of ESs, SESs and BBEs. The BIS performance objectives for equipment supporting packet layers, e.g., ETH Paths, T-MPLS Paths are based on the collection of ESs, SESs and BBEs or a subset of t
47、hose. These measurements are evaluated in the management system and/or the NE over periods of 15 minutes, 2 hours, 1 day and 4 Rec. ITU-T G.7710/Y.1701 (2007)/Amd.1 (07/2010) 7 days. For the declaration of a SES, see the technology-specific ITU-T Recommendations, e.g., ITU-T M.2101 defines the SDH B
48、IS performance objectives in full detail. The 15-minute and 24-hour registers should provide the capability to be reset to zero at the conclusion of the BIS intervals. If the history is stored as a log record, the capability to delete the log entries should be provided. 3.4) Clause 10.1.4 Update cla
49、use 10.1.4 as follows: 10.1.4 Quality of Service Quality of service (QoS) deals with service quality criteria stated in service provider specifications or service level agreements (SLAs) between service providers, or service providers and customers. In general, SLAs are applicable when there is a relationship, e.g., between a customer and an operator, or between a lead operator and several carriers. At a minimum, the SLA contains specifications for the grade of service to be delivered. Because of service provider specifications a
