1、 International Telecommunication Union ITU-T G.971TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2010) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Optical fibre submarine cable systems General features of optical fibre submarin
2、e cable systems Recommendation ITU-T G.971 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 CHARACT
3、ERISTICS 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 TRANSM
4、ISSION 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 General G.900G.909 Parameters for optical fibre cable systems G.910G.919 Digital sections at hierarchical bit rates based
5、 on a bit rate of 2048 kbit/s G.920G.929 Digital line transmission systems on cable at non-hierarchical bit rates G.930G.939 Digital line systems provided by FDM transmission bearers G.940G.949 Digital line systems G.950G.959 Digital section and digital transmission systems for customer access to IS
6、DN G.960G.969 Optical fibre submarine cable systems G.970G.979Optical line systems for local and access networks G.980G.989 Access networks G.990G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER
7、 TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.971 (07/2010) i Recommendation ITU-T G.971 General features of optical fibre submarine cable systems Su
8、mmary Recommendation ITU-T G.971 applies to optical fibre submarine cable systems. The purpose of this Recommendation is to identify the main features of optical fibre submarine cable systems, and to provide generic information on relevant Recommendations in the field of optical fibre submarine cabl
9、e systems. A common implementation relevant to all the optical fibre submarine cable systems is described in Annex A. Specific information relevant to each optical fibre submarine cable systems is included in annexes of other Recommendations. The updated data on cable ships and submersible equipment
10、 of various countries are also described in Appendix I. History Edition Recommendation Approval Study Group 1.0 ITU-T G.971 1993-03-12 XV 2.0 ITU-T G.971 1996-11-11 15 3.0 ITU-T G.971 2000-04-04 15 4.0 ITU-T G.971 2004-06-13 15 5.0 ITU-T G.971 2007-07-29 15 6.0 ITU-T G.971 2010-07-29 15 ii Rec. ITU-
11、T G.971 (07/2010) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is re
12、sponsible 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 th
13、e 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 collabor
14、ative 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 certain
15、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 requirement
16、s. 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. ITU
17、 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 not received notice of intellectual p
18、roperty, 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 2010 All rights reser
19、ved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.971 (07/2010) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 3.1 Terms defined elsewhere 1 4 Abbreviations and acronyms 1 5 Conventions 2 6 Features of
20、optical fibre submarine cable systems . 2 7 Relationship among Recommendations relevant to optical submarine cable systems 3 Annex A Common implementation aspects of optical submarine cable systems for manufacturing, installing and maintenance 5 A.1 Introduction 5 A.2 Manufacturing 5 A.3 System inst
21、allation 6 A.4 System commissioning . 7 A.5 Maintenance . 7 Appendix I Data on cable ships and submersible equipments of various countries . 9 I.1 Cable ships 9 I.2 Submersible equipments . 14 Bibliography. 21 Rec. ITU-T G.971 (07/2010) 1 Recommendation ITU-T G.971 General features of optical fibre
22、submarine cable systems 1 Scope This Recommendation applies to optical fibre submarine cable systems. The purpose of this Recommendation is to identify the main features of optical fibre submarine cable systems, and to provide generic information on relevant Recommendations in the field of optical f
23、ibre submarine cable systems. Annex A contains common implementation aspects of all optical submarine cable systems. Appendix I contains data on cable ships and submersible equipments of various countries. 2 References The following ITU-T Recommendations and other references contain provisions which
24、, 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 the possibility of app
25、lying 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 Recommendation. ITU-
26、T G.821 Recommendation ITU-T G.821 (2002), Error performance of an international digital connection operating at a bit rate below the primary rate and forming part of an Integrated Services Digital Network. ITU-T G.972 Recommendation ITU-T G.972 (2004), Definition of terms relevant to optical fibre
27、submarine cable systems. ITU-T G.973 Recommendation ITU-T G.973 (2007), Characteristics of repeaterless optical fibre submarine cable systems. ITU-T G.973.1 Recommendation ITU-T G.973.1 (2009), Longitudinally compatible DWDM applications for repeaterless optical fibre submarine cable systems. ITU-T
28、G.974 Recommendation ITU-T G.974 (2007), Characteristics of regenerative optical fibre submarine cable systems. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the terms defined in ITU-T G.972. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and a
29、cronyms: BAS Burial Assessment Survey BOL Beginning of Life BU Branching Unit CPT Cone Penetrometer Testing CTE Cable Terminating Equipment 2 Rec. ITU-T G.971 (07/2010) DP-system Dynamic Positioning-system DWDM Dense Wavelength Division Multiplexing PFE Power Feeding Equipment PLGR Pre-Lay Grapnel R
30、un ROV Remotely Operated Vehicle SCARAB Submersible Craft Assisting Repair and Burial SWL Safe Working Load TSE Terminal Station Equipment TTE Terminal Transmission Equipment 5 Conventions This clause is intentionally left blank. 6 Features of optical fibre submarine cable systems An optical fibre s
31、ubmarine cable system has specific technical features: a) A submarine cable system should achieve a long lifetime and a high reliability; the main reason is that, due to the difficulty in accessing the submerged plant, the construction and maintenance of a link is long and expensive; moreover, most
32、of submarine links are of strategic importance in the transmission network and the interruption of a link usually results in significant loss of traffic and revenue. b) A submarine cable system should possess mechanical characteristics which enable it: 1) to be installed accurately with correct slac
33、k and with due safety consideration on the seabed; deep water installations may reach 8000 metres. (In general, submarine cable systems shall be installed, buried or inspected by specially designed cable ships and submerged equipments. Detailed information of such cable ships and submerged equipment
34、s (i.e., ploughs, ROVs, etc.) is contained in Appendix I); 2) to resist the sea bottom environment condition at the installation depth, and particularly hydrostatic pressure, temperature, abrasion, corrosion, and marine life; 3) to be adequately protected (i.e., by armouring or burying) against aggr
35、ession, due for example to trawlers or anchors; 4) to survive recovery from such a depth, and subsequent repair and relay, with due safety consideration. c) The material characteristics of a submarine cable system should enable the optical fibre: 1) to achieve its desired reliability over its design
36、 lifetime; 2) to tolerate stated loss and aging mechanisms, especially bending, strain, hydrogen, stress, corrosion and radiation. d) The transmission quality of a submarine cable system should follow as a minimum ITU-T G.821. Figure 1 shows the basic concept of optical fibre submarine cable systems
37、 and boundaries. Optical submarine repeaters or optical submarine branching units could be included, depending on each system requirement. In Figure 1, “A“ denotes the system interfaces at the terminal station (where the system can be interfaced to terrestrial digital links or to other submarine cab
38、le systems), and “B“ denotes beach joints or landing points. Numbers in brackets in the figure refer to ITU-T G.972. Rec. ITU-T G.971 (07/2010) 3 G.971(10)_F01Land portion (1004) Submarine portion (1005) Land portion (1004)TTE(1010)CTE(1014)Opticalsubmarinerepeater(1020) RepeaterBU(1022) Repeater Re
39、peaterASBBRACTE TTESupervisorysection(2007)Elementarycable section(1028)ABCTE TTEPFE MaintenancecontrollerPFE MaintenancecontrollerMaintenancecontroller(1012)Cablejointingbox (5013)NOTE 1 denotes system interface.NOTE 2 denotes landing points or beach joints (1006).NOTE 3 denotes cable jointing box
40、(5013).NOTE 4 Number in brackets relate to ITU-T G.972.A B XO IRepeaterRepeaterPFE(1013)Optical fibre submarine cable (1019)Optical fibre land cable (1018)Optical fibre station cable (1017)Electrical cableOptical interface (2009)System interface (2008)Figure 1 Example of optical fibre submarine cabl
41、e systems 7 Relationship among Recommendations relevant to optical submarine cable systems Relationships among the various Recommendations pertaining to optical fibre submarine cable systems are shown in the flow chart presented in Figure 2. 4 Rec. ITU-T G.971 (07/2010) G.971(10)_F02Characteristics
42、of opticalfibre submarine cablesb-ITU-T G.978Test methodsb-ITU-T G.976Forward error correction for submarine systemsb-ITU-T G.975DefinitionsITU-T G.972General featuresITU-T G.971Forward error correction for high bit-rate DWDM submarine systemsb-ITU-T G.975.1Regenerative submarine systemsITU-T G.974O
43、ptically amplified submarine systemsb-ITU-T G.977Repeaterlesssubmarine systemsITU-T G.973Design guidelines forsubmarine systemsb-ITU-T G-Sup.41Longitudinal compatibleDWDM application forrepeaterless submarine systemsITU-T G.973.1Figure 2 Relationships amongst Recommendations relevant to optical subm
44、arine cable systems Rec. ITU-T G.971 (07/2010) 5 Annex A Common implementation aspects of optical submarine cable systems for manufacturing, installing and maintenance (This annex forms an integral part of this Recommendation) A.1 Introduction This annex outlines the common aspects of submarine cabl
45、e systems, which are specified in ITU-T G.973, ITU-T G.973.1, ITU-T G.974 and ITU-T G.977, such as manufacturing, installation, and maintenance. The information provided in this annex is intended as a guide to current practice and is not intended as a Recommendation relating to existing or future sy
46、stems. A.2 Manufacturing A.2.1 Quality in optical fibre submarine cable systems The high performance and reliability requirement established for an optical fibre submarine cable system can be fulfilled only if stringent quality procedures are applied during designing, manufacturing, and laying of a
47、system. Although quality procedures are particular to each optical fibre submarine cable supplier, the following basic principles generally apply. A.2.1.1 Qualification of the designs and technologies This activity, part of the development process, is intended to demonstrate that the performance of
48、a technology, a component or an assembly is compatible with meeting the overall system performance requirements and provides reasonable assurance that the reliability target can be met. Qualification includes high-stress testing, intended to estimate the ruggedness of the technology, component or su
49、bassembly and to determine the screening procedure, and long-term life testing (some of which might be accelerated for instance by the temperature), the purpose of which is to confirm the validity of the screening procedure and to evaluate the lifetime and/or the reliability of the technology, component or assembly. Qualification of a cable or submarine equipment may also include sea trials. A.2.1.2 Certification of components and sub-assemblies This activity, part of the manufacturing
