1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T L.310 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (04/2016) SERIES L: ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE P
2、LANT Maintenance and operation Optical fibre cable maintenance Optical fibre maintenance depending on topologies of access networks Recommendation ITU-T L.310 ITU-T L-SERIES RECOMMENDATIONS ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF
3、 CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT OPTICAL FIBRE CABLES Cable structure and characteristics L.100L.124 Cable evaluation L.125L.149 Guidance and installation technique L.150L.199 OPTICAL INFRASTRUCTURES Infrastructure including node element (except cables) L.200L.249 General aspects and netw
4、ork design L.250L.299 MAINTENANCE AND OPERATION Optical fibre cable maintenance L.300L.329 Infrastructure maintenance L.330L.349 Operation support and infrastructure management L.350L.379 Disaster management L.380L.399 PASSIVE OPTICAL DEVICES L.400L.429 MARINIZED TERRESTRIAL CABLES L.430L.449 For fu
5、rther details, please refer to the list of ITU-T Recommendations. Rec. ITU-T L.310 (04/2016) i Recommendation ITU-T L.310 Optical fibre maintenance depending on topologies of access networks Summary Recommendation ITU-T L.310 deals with optical fibre maintenance depending on topologies of access net
6、works. It describes the fundamental requirements, maintenance section, testing and maintenance items, and methods for developing a suitable guide to maintaining point-to-multipoint and ring optical networks, respectively. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T L.310
7、/L.53 2003-05-14 6 11.1002/1000/6319 2.0 ITU-T L.310 2016-04-13 15 11.1002/1000/12836 Keywords Network, optical fibre maintenance, OTDR reflecting device, OTDR testing point-to-multipoint access, ring access network. * To access the Recommendation, type the URL http:/handle.itu.int/ in the address f
8、ield of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T L.310 (04/2016) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, informatio
9、n and communication 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 worldwid
10、e 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 in WTSA
11、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 administra
12、tion and a 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 provision
13、s are met. 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 RIGHTSITU draws attention to the
14、 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 applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of
15、 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 implement this Recommendation. However, implementers are cautioned that this may not represent the latest i
16、nformation and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2016 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 L.310 (04/2016) iii Table of C
17、ontents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 Fundamental requirements 2 6.1 Network topologies 2 6.2 Maintenance section . 3 6.3 Testing and maintenance items 4 7
18、Testing and maintenance methods 5 7.1 Testing and maintenance methods for point-to-multipoint access networks5 7.2 Testing and maintenance methods for ring access networks 6 8 Testing and maintenance wavelength . 7 9 Requirements for in-service testing beyond optical splitter utilizing OTDR reflecti
19、ng devices in point-to-multipoint access network . 8 9.1 General . 8 9.2 Requirements for deployment conditions . 8 9.3 Requirements for operational conditions 10 9.4 Procedure and interpretation of results . 10 Appendix I Practical solutions for point-to-multipoint access network . 11 I.1 Japanese
20、experience 11 I.2 Chinese experience . 14 Appendix II Practical solutions for ring access network 23 II.1 Indonesian experience 23 II.2 Japanese experience 26 Bibliography. 29 iv Rec. ITU-T L.310 (04/2016) Introduction The point-to-multipoint and ring network architectures are very important in term
21、s of constructing optical fibre networks both effectively and inexpensively. However, some considerations on the testing and maintenance methods are required for the point-to-multipoint and ring network architectures in addition to conventional single star architecture. In this Recommendation, topol
22、ogy-specific maintenance items and test methods are identified for the point to multi-point and ring network architecture. Rec. ITU-T L.310 (04/2016) 1 Recommendation ITU-T L.310 Optical fibre maintenance depending on topologies of access networks 1 Scope This Recommendation describes the maintenanc
23、e section, testing and maintenance functions, and methods for both point-to-multipoint and ring networks in the access network. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation
24、. 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 applying the most recent edition of the Recommendations and other references list
25、ed 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-T L.300 Recommendation ITU-T L.300/L.25 (2015), Optical fibre cable network ma
26、intenance. ITU-T L.301 Recommendation ITU-T L.301/L.41 (2000), Maintenance wavelength on fibres carrying signals. ITU-T L.302 Recommendation ITU-T L.302/L.40 (2000), Optical fibre outside plant maintenance support, monitoring and testing system. ITU-T L.313 Recommendation ITU-T L.313/L.66 (2007), Op
27、tical fibre cable maintenance criteria for in-service fibre testing in access networks. ITU-T L.314 Recommendation ITU-T L.314/L.85 (2010), Optical fibre identification for the maintenance of optical access networks. IEC 61746-1 IEC 61746-1 (2009), Calibration of optical time-domain reflectometers (
28、OTDR). IEC 61753-041-2 IEC 61753-041-2 (2014), Fibre optic interconnecting devices and passive components Performance standard Part 041-2: Non-connectorized single-mode OTDR reflecting device for category C Controlled environment. IEC 61753-042-2 IEC 61753-042-2 (2014), Fibre optic interconnecting d
29、evices and passive components Performance standard Part 042-2: Plug-pigtail-style and plug-receptacle-style of OTDR reflecting devices for category C Controlled environments. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 surveillance:
30、 ITU-T L.300 3.1.2 control: ITU-T L.300 3.1.3 OTDR reflecting device: IEC 61753-041-2 2 Rec. ITU-T L.310 (04/2016) 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 maintenance section: An area of optical fibres that is tested and maintained in an access
31、 network. 3.2.2 apparent return loss: A return loss calculated from the difference between superimposed backscatter level from multiple branch fibres and reflection level on OTDR trace. The apparent is used to distinguish from the return loss measured without any branches as in IEC 61746-1. 4 Abbrev
32、iations and acronyms This Recommendation uses the following abbreviations and acronyms: ADM Add-Drop Multiplexer B-OTDR Brillouin Optical Time Domain Reflectometer CB Customer Building CO Central Office FBG Fibre Bragg Grating H-OTDR High spatial resolution Optical Time Domain Reflectometer ID light
33、 Identification light OLT Optical Line Terminal ONU Optical Network Unit OTDR Optical Time Domain Reflectometer PON Passive Optical Network 5 Conventions None. 6 Fundamental requirements 6.1 Network topologies 6.1.1 Point-to-multipoint access network The basic configuration of a point-to-multipoint
34、access network is shown in Figure 1. Case 1: Indoor splitter in CO; Case 2: Outdoor splitter; Case 3: Indoor splitter in CB. Rec. ITU-T L.310 (04/2016) 3 Figure 1 Configuration of point-to-multipoint access network 6.1.2 Ring access network The basic configuration of a ring access network is shown i
35、n Figure 2. Figure 2 Configuration of ring access network 6.2 Maintenance section A maintenance section is classified as follows. 6.2.1 Maintenance section of point-to-multipoint access network The maintenance sections of the point-to-multipoint access network in Figure 1 are as follows: Case 1: Opt
36、ical fibre between the OLT and the ONU as shown in Figure 1 case 1 (All sections); Case 2: Optical fibre between the OLT and the ONU as shown in Figure 1 case 2 (All sections); Case 3: Optical fibre between the OLT and the indoor splitter. 4 Rec. ITU-T L.310 (04/2016) 6.2.2 Maintenance section of ri
37、ng access network The maintenance section of the ring access network in Figure 2 consists of all sections of the ring access network. 6.3 Testing and maintenance items 6.3.1 Testing and maintenance items for point-to-multipoint access networks Maintenance items for point-to-multipoint access network
38、s are classified as shown in Table 1. Table 1 Testing and maintenance items for point-to-multipoint access networks Category Activity Testing and maintenance item Status Preventative maintenance Surveillance (e.g., Periodic testing, Continuous testing) Detection of fibre loss increase Detection of s
39、ignal power loss increase Detection of water penetration Optional Optional Optional Testing (e.g., Fibre degradation testing) Measurement of fibre fault location Measurement of fibre strain distribution Measurement of water location Optional Optional Optional Control (e.g., Network element control)
40、Fibre identification Fibre transfer Optional Optional After installation before service or post-fault maintenance Surveillance (e.g., Reception of transmission system alarm or customer trouble report) Refer to alarm from path operation system Refer to alarm from customer service operation system Opt
41、ional Optional Testing (e.g., After installation testing, Fibre fault testing) Confirmation of fibre condition Fault identification between transmission equipment and fibre network Measurement of fibre fault location Fault responsibility demarcation of trunk cable and/or branch cable Measurement of
42、splitter degradation Fault classification Required Required Required Optional Optional Optional Control (e.g., Cable install/repair/ replacement) Fibre identification Fibre transfer Storage of outside plant database Information on cable route Required Optional Required Optional 6.3.2 Testing and mai
43、ntenance items for ring access networks Maintenance items for ring access networks are classified as shown in Table 2. Table 2 Testing and maintenance items for ring access networks Category Activity Testing and maintenance item Status Preventative maintenance Surveillance Detection of fibre loss in
44、crease Detection of signal power loss increase Detection of water penetration Optional Optional Optional Rec. ITU-T L.310 (04/2016) 5 Table 2 Testing and maintenance items for ring access networks Category Activity Testing and maintenance item Status Testing Measurement of fibre fault location Measu
45、rement of fibre strain distribution Measurement of water location Optional Optional Optional Control Fibre identification Fibre transfer Optional Optional After installation before service or post-fault maintenance Surveillance Refer to alarm from path operation system Refer to alarm from customer s
46、ervice operation system Optional Optional Testing Confirmation of fibre condition Fault identification between transmission equipment and fibre network Measurement of fibre fault location Required Required Required Control Fibre identification Fibre transfer Storage of outside plant database Informa
47、tion on cable route Required Optional Required Optional 7 Testing and maintenance methods There are several ways to implement these testing and maintenance items. Optical time domain reflectometer (OTDR) testing, loss testing, monitoring a proportion of the signal power (power monitoring) and identi
48、fication light detection are commonly used. The most common methods are described below. 7.1 Testing and maintenance methods for point-to-multipoint access networks Table 3 Suitable test methods for point-to-multipoint access networks Category Activity Item Methods Preventative maintenance Surveilla
49、nce Detection of fibre loss increase Detection of signal power loss increase Detection of water penetration OTDR/loss testing Power monitoring OTDR testing Testing Measurement of fibre fault location Measurement of fibre strain distribution Measurement of water location Measurement of trunk fibre and/or branch fibre degradation Measurement of splitter degradation OTDR testing (Note 1) B-OTDR testing OTDR testing (Note 1) OTDR testing (Note 1/Note 4) OTDR testing (Note 1/Note 4) Control Fibre identifica
