1、STD-ITU-T RECMN M.1375-ENGL 1998 = 48b2591 Ob53807 447 = INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STAN DARD IZATI ON SECT0 R OF ITU MA375 (06/98) SERIES M: TMN AND NETWORK MAINTENANCE: INTERNATIONAL TRANSMISSION SYSTEMS, TELEPHONE CIRCUITS, TELEGRAPHY, FACSIMILE AND LEASED CIRCU
2、ITS International data transmission systems Mai n te na nce of in terna t i o na1 da ta t ra nsm iss i on systems ITU-T Recommendation M.1375 (Previously CCIlT Recommendation) ITU-T M-SERIES RECOMMENDATIONS TMN AND NETWORK MAINTENANCE: INTERNATIONAL TRANSMISSION SYSTEMS, TELEPHONE CIRCUITS, TELEGRAP
3、HY, FACSIMILE AND LEASED CIRCUITS Introduction and general principles of maintenance and maintenance organization International transmission systems International telephone circuits Common channel signalling systems International telegraph systems and phototelegraph transmission International leased
4、 group and supergroup links International leased circuits Mobile telecommunication systems and services M. 10-M.299 M.300-M.559 M.560-M.759 M.760-M.799 M. 800-M. 899 M.900-M.999 M. 1000-M. 1099 M. 1 100-M. 1 199 International public telephone network M. 12O-M. 1299 Designations and information excha
5、nge International transport network Telecommunications management network Integrated services digital networks Common channel signalling systems M.1400-M.1999 M.2000-M.2999 M.3000-M.3599 M.3600-M.3999 M.4000-M.4999 For further details, please refer to ITU-T List ofRecommendations. ITU-T RECOMMENDATI
6、ON M.1375 MAINTENANCE OF INTERNATIONAL DATA TRANSMISSION SYSTEMS Summary This Recommendation describes the procedures and tests for the maintenance of international data transmission systems with a PDH presentation. Source IT-T Recommendation M.1375 was revised by IT-T Study Group 4 (1997-2000) and
7、was approved under the WTSC Resolution No. 1 procedure on the 26th of June 1998. Keywords Fault information exchange, fault localization, fault reporting procedure, in-service monitoring, international data transmission link, international data transmission system, international leased circuit, main
8、tenance, planned Maintenance. Recommendation M.1375 (06/98) 1 STD-ITU-T RECMN M.b375-ENGL 1998 48b2591 Ob5LBLO T31 W FOREWORD IT (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommuni- cations. The IT Telecommunication Standardization Sector (ITU
9、-T) is a permanent organ of the ITU. The 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. The World Telecommunication Standardization Conference (WTSC), which meets ev
10、ery four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technolog
11、y which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL
12、 PROPERTY RTGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, w
13、hether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors
14、 are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 1998 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopyi
15、ng and microfilm, without permission in writing from the ITU. 11 Recommendation M.1375 (06198) CONTENTS 8 9 10 11 12 13 14 Scope References Terminology and definitions Performance limits and objectives Fault reporting procedures 7.1 Control and sub-control status 7.2 Fault information exchange . Abb
16、reviations . Maintenance records . Fault localization Maintenance tests . 9.1 General 9.2 Maintenance intervention tests 9.3 9.4 Loopback tests . 9.5 Test access at Digital Cross-Connect (DXC) equipment In-service monitoring . Temporary service restoration 11.1 Mechanisms for implementing temporary
17、service restoration 1 1.2 Time to restore service 11.3 Restoration procedure . 1 1.4 11.5 Returning to service tests Retuming to normal routing Information that should be exchanged Automatic rerouting of international data transmission links . Precautions to be taken in the use of DXCs . Planned mai
18、ntenance Recommendation M.1375 (06/98) Page 1 1 4 9 9 10 . 111 Recommendation M.1375 MAINTENANCE OF INTERNATIONAL DATA TRANSMISSION SYSTEMS (Published in 1984; revised in 1988, I993, I996 and 1998) 1 Scope The requirements of this Recommendation are intended to ensure effective maintenance of intern
19、ational data transmission systems. The aim of this Recommendation is to minimize the number and duration of any interruptions to the customers international leased circuit. 2 References The following ITU-T Recommendations contain provisions which, through reference in this text, constitute provision
20、s of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendatio
21、ns listed below. A list of the currently valid ITU-T Recommendations is regularly published. ITU-T Recommendation M.60 (1993), Maintenance terminology and definitions. CC1T“T Recommendation M.80 (1 988), Control stations. CCITT Recommendation M.90 (1 988), Sub-control stations. CCITT Recommendation
22、M. 1 O 12 (1 988), Circuit control station for leased and special circuits. CCITT Recommendation M.1013 (1988), Sub-control station for leased and special circuits. ITU-T Recommendation M. 1045 (1 996), Preliminary exchange of information for the provision of international leased circuits and intern
23、ational data transmission sysems. ITU-T Recommendation M. 1300 (1 997), Maintenance of international data transmission systems operating in the range 2.4 kbit/s to 140 Mbit/s. ITU-T Recommendation M. 1340 (1 996), Perfarmanee allocations and limits for international data transmission links and syste
24、ms. ITU-T Recommendation M. 13 70 ( 1993), Bringing-into-service of international data transmission systems. ITU-T Recommendation M.1385 (1993), Maintenance of international leased circuits that are supported by international data transmission systems. ITU-T Recommendation M.1400 (1997), Designation
25、s for international nefwork. ITU-T Recommendation M. 1540 (1 994), Exchange of information for planned outages of transmission systems. CCITT Recommendation M. 1560 (1 992), Escalation procedure for international leased circuits. ITU-T Recommendation M.2 1 O0 ( 19954 Performance limits for bringing-
26、into-service and maintenance of international PDH paths, sections and transmission systems. ITU-T Recommendation M.2 1 1 O (1997), Bringing-into-service of international PDH paths, sections and transmission systems and SDH paths and multiplex sections. Recommendation M.1375 (06/98) 1 ITU-T Recommend
27、ation M.2120 (1997), PDH path, section and transmission system and SDH paths and multiplex section fault detection and localization procedures. ITU-T Recommendation G.701 (1993), Vocabulary of digital transmission and multiplexing, and Pulse Code Modulation (PCM) terms. ITU-T Recommendation G.704 (1
28、995), Synchronous fiame structures used at 1544, 6312, 2048, 8448 und 44 736 kbits hierarchical levels. CCITT Recommendation G.706 (1 99 i), Frame alignment and Cyclic Redundancy Check (CRC) procedures relating to basic fiame structures dejned in Recommendation G. 704. ITU-T Recommendation G.736 (19
29、93), Characteristics of a synchronous digital multiplex equipment operating at 2048 kbits. ITU-T Recommendation G.783 (1997), Characteristics of Synchronous Digital Hierarchy (SDH) equipment jnctional blocks. CCITT Recommendation G.796 (1992), Characteristics of a 64 kbith cross-connect equipment wi
30、th 2048 kbits access ports. CCITT Recommendation X.50 (1988), Fundamental parameters of a multiplexing scheme for the international interface between synchronous data networks. Terminology and definitions Recommendation M. 1300 7 provides general descriptions of international data transmission links
31、 and international data transmission systems. Terminologies and definitions relating to this Recommendation are provided in Recommendations M.60 11 and G.701 17. For the purposes of this Recommendation the following definition applies: The term “structured“ (sometimes known as “framed“) indicates th
32、at a frame structure such as those defined in Recommendation G.704 181 is used. 4 Abbreviations This Recommendation uses the following abbreviations: CRC Cyclic Redundancy Check CSES Consecutive Severely Errored Seconds DXC Digital Cross-Connect ES Errored Second SDH Synchronous Digital Hierarchy SE
33、S Severely Errored Second TMN Telecommunications Management Network UTC Coordinated Universal Time 5 Performance limits and objectives Recommendation M. 1340 SI covers all performance limits and objectives associated with this Recommendation. For all performance tests described in this Recommendatio
34、n, the Errored Second (ES) and Severely Errored Second (SES) limits should be met simultaneously for the test result to be considered acceptable. Additionally, periods of Consecutive Severely Errored Seconds (CSES) should be avoided as these can cause a severe impact on some customers applications t
35、hat are supported by international data transmission systems, (see clause 5M.1385 lo). 2 Recommendation M.1375 (0698) 6 Maintenance records Network Operators/Service Providers should ensure that up-to-date information is held on file to assist with maintenance activities. In particular, Network Oper
36、ators/Service Providers should aim to hold all information highlighted in clause 6M.1370 9. 7 Fault reporting procedures 7.1 Control and sub-control status At the bnnging-into-service stage, Network OperatorsService Providers will have agreed on a dual control or on a control and sub-control relatio
37、nship for the terminal stations of an intemational data transmission system (see clause lOM.1300 7). Where a control and sub-control relationship exists, responsibilities will be as described in Recommendations M.80 2, M.90 3, M.1012 4 and M.1013 5. Where a dual control relationship has been establi
38、shed, Network OperatordService Providers should have agreed an effective mechanism for coordinating maintenance activities. Under this arrangement, to avoid confusion, it is essential that the terminal stations inform each other of maintenance activities as rapidly as possible. 7.2 Fault information
39、 exchange In general, fault information relating to an international data transmission system can originate fiom four sources: - - a customer (due to the failure or poor performance of an international leased circuit); a lower order system operator (due to the failure or poor performance of a lower
40、order system that is supported as a channel on this system); the system itself (through alarms or distant operator); a network or higher order system operator (with notification of the failure or poor performance of the higher order network that supports this system or recognition of a transmit prob
41、lem from this system). - - Where fault information is received directly from a customer, reference should additionally be made to Recommenda- tion M.1385 lo. During fault localization and clearance, fault information exchange should be as indicated in Figure 1, Where a fault is passed from one opera
42、tor to another, or between Network Operators/Service Providers, as much information as possible should be exchanged including: - - the name, title and contact details for the person reporting the fault; time of fault report, recorded in UTC; - - symptoms of the fault; - - fault reference numbers; -
43、The above fault information may be exchanged electronically, for example, using a TMN X interface. designation of the faulty system (see Recommendation M. 1400 1 i); the observed duration of the fault prior to a report being made; any associated information that may assist with fault clearance. The
44、terminology covering lower order systems and higher order systems relates to the hierarchical transmission data rate of the terminal multiplexing equipments that are interconnected to support service. A typical lower and higher order system relationship would exist where a 64 kbits international dat
45、a transmission system (see Recommendation X.50 23) is supported as a channel on a 2048 kbits intemational data transmission system (see Recommendation G.736 20). Recommendation M.1375 (06/98) 3 STBmITU-T RECMN M.1375-ENGL 1998 48b259L Ob5L815 513 When a fault is cleared, appropriate clearance inform
46、ation should be passed to stations that had been involved with initial fault reporting and localization. 8 Fault localization Figure 1 provides a systematic and coordinated procedure for efficient fault localization. Initial localization should aim to identi as quickly as possible whether the fault
47、is due to the international data transmission link or the terminal multiplexing equipment2. Subsequent localization should aim to identi the specific link section or equipment that has failed. Where the TMN methodology is used, automatic identification of the exact cause of problems may greatly simp
48、liSr fault monitoring and localization. Where fault localization is not achieved in a reasonable time, Network Operators/Service Providers shall invoke the agreed escalation procedure (see Recommendation M.1560 131) to assist progress. 9 Maintenance tests 9.1 General Existing maintenance records sho
49、uld provide details of test equipment, test points, test patterns and performance limits that are to be used for the maintenance of specific international data transmission systems. Where information is incomplete or out of date, reference should be made to Recommendations M.1340 8 and M.1370 9 as appropriate. Maintenance tests should be kept as short as possible to avoid significantly extending out-of-service time. Care must be taken to avoid the use of loopbacks to localize system faults, as this may disrupt one or more customers
