1、 International Telecommunication Union ITU-T G.872TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(11/2013) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital networks Optical transport networks Architecture of optical transport networks Amendment 1 Recommendat
2、ion ITU-T G.872 (2012) 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 CHARACTERISTICS
3、 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 TRANSMISSION M
4、EDIA AND OPTICAL SYSTEMS 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 ch
5、aracteristics G.840G.849 Management of transport network G.850G.859 SDH radio and satellite systems integration G.860G.869 Optical transport networks G.870G.879DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1
6、999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER 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.872 (2012)/Amd.1 (11/2013) i Recommendatio
7、n ITU-T G.872 Architecture of optical transport networks Amendment 1 Summary Amendment 1 to Recommendation ITU-T G.872 (2012) describes the use of the black link approach defined in Recommendations ITU-T G.698.1 and ITU-T G.698.2 within the context of an OTN network. History Edition Recommendation A
8、pproval Study Group Unique ID*1.0 ITU-T G.872 1999-02-26 13 11.1002/1000/4576-en 2.0 ITU-T G.872 2001-11-29 15 11.1002/1000/5606-en 2.1 ITU-T G.872 (2001) Amd. 1 2003-12-14 15 11.1002/1000/7064-en 2.2 ITU-T G.872 (2001) Cor. 1 2005-01-13 15 11.1002/1000/7483-en 2.3 ITU-T G.872 (2001) Amd. 2 2010-07-
9、29 15 11.1002/1000/10880-en3.0 ITU-T G.872 2012-10-29 15 11.1002/1000/11786-en3.1 ITU-T G.872 (2012) Amd. 1 2013-11-06 15 11.1002/1000/11986-en_ *To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For
10、example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T G.872 (2012)/Amd.1 (11/2013) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommuni
11、cation 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. The World Telecommunication Standardization Assembl
12、y (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 1. In some areas of information technology which
13、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 recognized operating agency. Compliance with this
14、 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. The words “shall“ or some other obligatory langua
15、ge 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 possibility that the practice or implementation of this Re
16、commendation 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 Recommendation development process. As of the date of
17、approval of this Recommendation, ITU had 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 and are therefore strongly urged to consult the TSB
18、patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2014 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.872 (2012)/Amd.1 (11/2013) iii Table of Contents Page 1) Introduction 1 2) Changes 1 2.1) A
19、dditions to clause 4 1 2.2) Clause 8.4.2 1 2.3) Clause 10.2.1 1 2.4) Clause 12 2 3) Deletions . 3 3.1) Appendix III . 3 4) Editorial changes 3 4.1) Clause 6 3 4.2) Appendix IV . 4 Rec. ITU-T G.872 (2012)/Amd.1 (11/2013) 1 Recommendation ITU-T G.872 Architecture of optical transport networks Amendmen
20、t 1 1) Introduction This amendment contains extensions to the third version (10/2012) of Recommendation ITU-T G.872 which relate to: the use of the black link approach defined in ITU-T G.698.1 and ITU-T G.698.2 in the context of an OTN network. 2) Changes 2.1) Additions to clause 4 Add the following
21、 abbreviations to clause 4: OCC Overhead Communications Channel OCN Overhead Communications Network 2.2) Clause 8.4.2 Replace the text of the first paragraph of clause 8.4.2 with the following: The media channel is a topological construct that represents both the path through the media and the resou
22、rce (frequency slot) that it occupies. A media channel is bounded by ports on media elements. A media channel can span any combination of network elements and fibres. A media channel may not be capable of supporting any OCh-P signal. The size of a media channel is specified by its effective frequenc
23、y slot, which is described by its nominal central frequency and its slot width ITU-T G.694.1. The effective frequency slot of a media channel is that part of the frequency slots of the filters along the media channel that is common to all of the filters frequency slots. The parameters “n“ and “m“ as
24、 defined in clause 7 of ITU-T G.694.1, are used to describe the effective frequency slot with the exception that n and m (for cases where the n value of the constituent filters frequency slots are not all the same) may have a granularity of 0.5 rather than being integers. A media channel may be dime
25、nsioned to carry more than one OCh-P signal. Also the effective slot width of a media channel may be administratively set to be less than the maximum slot width supported by the filter components on the media channel. A media channel may be configured before it has been decided which OCh-P signals i
26、t will be allocated to. 2.3) Clause 10.2.1 Modify the text in the connectivity supervision part of clause 10.2.1 as follows: Connectivity supervision Connectivity supervision refers to the set of processes for monitoring the integrity of the routing of the connection between source and sink trail te
27、rminations. Connectivity supervision is necessary to confirm proper routing of a connection between trail termination source and sink during the connection set-up process. Furthermore, connectivity supervision is needed to ensure that connectivity is maintained while the connection is active. The fo
28、llowing process is identified for connectivity supervision: 2 Rec. ITU-T G.872 (2012)/Amd.1 (11/2013) Trail trace identification (TTI) TTI is necessary to ensure that the signal received by a trail termination sink originates from the intended trail termination source. The following requirements are
29、 identified: TTI is necessary in the OTS_ME to ensure proper cable connection; TTI is not needed in the OMS_ME because there is a one-to-one relationship between the OTS and the OMS_ME, i.e., media connectivity in the OMS_ME is fixed; therefore, the OMS-P channel is already covered by the OTS-O TTI.
30、 Flexible connectivity in the OMS-P channel is not envisaged. TTI at the OCh-P layer is not needed because there is a one-to-one relationship between the OCh-P trail and the OTU trail; TTI is necessary at the OTU layer to ensure proper OCh connections; TTI is necessary at the ODU layer to ensure pro
31、per ODU layer connections. When the OCh-O is carried by an OCN/OCC (see clause 12) it is necessary to carry a TTI and the nominal central frequency of the associated OCh-P with the OCh-O in the OCC to ensure there are no misconnections across the OCN. Detection of connectivity defects will lead to t
32、he same consequent actions as described above for the detection of loss of continuity for the characteristic information. 2.4) Clause 12 Replace clause 12 with the text below: 12 The black link approach The black link approach is described in ITU-T G.698.1 and ITU-T G.698.2. The specification method
33、 used in these Recommendations uses a “black link“ approach which means that optical interface parameters for only (single-channel) optical tributary signals and the transfer function of the media path are specified by a set of application codes. Use of a common application code ensures the compatib
34、ility of the media path, transmitter and receiver. This approach enables transverse compatibility at the single-channel point using a direct wavelength-multiplexing configuration. However, it does not enable transverse compatibility at the multichannel points. The black link approach may be used to
35、provide an OCh-P network connection between an OCh source/sink pair as shown in Figure 12-1. The OCh-P network connection is supported by a network media channel that is terminated by an OCh-P source and an OCh-P sink where each of these components may be provided by different vendors but must all b
36、e within the domain of a single network operator. The black link approach provides a media path, which is pre-certified for a particular intra-domain OCh-P, the characteristics of this signal at the SSand RSreference points are defined in ITU-T G.698.1 and ITU-T G.698.2. The media path is terminated
37、 by an OCh-P termination (which makes it the path that carries an OCh-P network connection) and has no internal structure visible from either termination. The OCh-O must also be supported; however, in this application it cannot be carried across the complete OCh network connection by the OSC as desc
38、ribed in clause 8. To complete the OCh-O connection, it is carried across the interface between the OCh subnetwork and the OCh source/sink by an OCC within the OCN as shown in Figure 12-1. Rec. ITU-T G.872 (2012)/Amd.1 (11/2013) 3 G.872(12)-Amd.1(13)_F12-1OCh-OSourceOCh-O APOCh-OCPOCh-OSinkOCh-PSink
39、OCh-PSourceOCh-O NCOCh-O trailOCh-OOCh-OMatrix channel Matrix channel Matrix channelOCh-OOCh-O APOch APOCh APOCh-O TCPOCh-P CPChannel portChannel portOCh-P CPOCh-PNIMOCh-PNIMOCh-P network connectionNetwork media channelMedia channel matrixMedia channel matrixMedia channel matrixOCh trailMIMIOCh-O OC
40、h-Ocarried byOSCcarried byOSCOCCOCN OCNOCCOCh-P LC OCh-P LCLink channel Link channelOCH subnetworkSSSSSRSRNOTE Ssand Rsin Figure 12-1 identify the reference points defined in ITU-T G.698.1 and ITU-T G.698.2. Figure 12-1 Example OCh subnetwork using the black link approach 3) Deletions 3.1) Appendix
41、III Delete Appendix III An example of the use of the black link approach. 4) Editorial changes 4.1) Clause 6 Modify footnote 3 in clause 6 as follows: 3This separation is necessary to allow the description of media elements that may act on more than a single OCh-P signal. The relationship between th
42、e model provided in this Recommendation and the existing functions and processes described in ITU-T G.798 is provided in Appendix IIIIV. 4 Rec. ITU-T G.872 (2012)/Amd.1 (11/2013) 4.2) Appendix IV Renumber Appendix IV as Appendix III and renumber Figure IV.1 as Figure III.1. Modify the text of Append
43、ix III (previously Appendix IV) as follows: This appendix describes the relationship between the model provided in this Recommendation and the existing functions and processes described in ITU-T G.798. Figure IVIII.1 illustrates that the additions to this Recommendation that support configurable med
44、ia elements and the ability to manage the media at a granularity that is greater than a single OCh-P have no effect on processes defined in ITU-T G.798. Printed in Switzerland Geneva, 2014 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles S
45、eries E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network S
46、eries J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and netwo
47、rk maintenance Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Terminals and subjective and objective assessment methods Series Q Switching and signalling Series R Telegraph transmission Series S Telegra
48、ph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
