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 G.698.4 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2018) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Transmission media and optical systems characteristics Characteristics of optical syst
2、ems Multichannel bi-directional DWDM applications with port agnostic single-channel optical interfaces Recommendation ITU-T G.698.4 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTE
3、RISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS 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 META
4、LLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 General G.600G.609 Symmetric cable pairs G.610G.619 Land coaxial cable pairs G.620G.629 Submarine cables G.630G.639 Free space optical systems G.640G.6
5、49 Optical fibre cables G.650G.659 Characteristics of optical components and subsystems G.660G.679 Characteristics of optical systems G.680G.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 PE
6、RFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 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
7、. ITU-T G.698.4 (03/2018) i Recommendation ITU-T G.698.4 Multichannel bi-directional DWDM applications with port agnostic single-channel optical interfaces Summary Recommendation ITU-T G.698.4 provides optical parameter values for physical layer interfaces of dense wavelength division multiplexing (
8、DWDM) systems primarily intended for metro applications, where the tail-end transmitters have the capability to automatically adapt their DWDM channel frequency to the optical demultiplexer/optical multiplexer (OD/OM) or optical add-drop multiplexer (OADM) port. Applications are defined using optica
9、l interface parameters and values for single-channel and multichannel interfaces of multichannel DWDM optical systems in point-to-point applications. This Recommendation uses a system architecture comprising a head-end, connecting to the tail-end equipment (TEE) through a black link. The head end ho
10、uses a set of transmitters and receivers and an OD/OM. A single bidirectional fibre is used to connect the head-end to the black link OD/OM or OADM. The connection between the OD/OM/OADM and the TEE is also bidirectional. The initial version of this Recommendation includes DWDM applications up to 10
11、 Gbit/s with channel frequency spacing of 50 GHz and 100 GHz. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.698.4 2018-03-16 15 11.1002/1000/13519 Keywords Application codes, bidirectional, DWDM, black link, head-end, message channel, metro, multi-vendor, OADM, optical,
12、pilot tone, port agnostic, tail-end. * 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 example, http:/handle.itu.int/11.1002/1000/ 11830-en. ii Rec. ITU-T G.698.4 (03/2018) FOREWORD The Internat
13、ional 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 responsible for studying technical, opera
14、ting 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 the ITU-T study groups which, in turn, pr
15、oduce 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 collaborative basis with ISO and IEC. NOTE In t
16、his 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 mandatory provisions (to ensure, e.g.,
17、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 requirements. The use of such words does not sugge
18、st that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the 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 eviden
19、ce, 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 property, protected by patents, which may
20、 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 2018 All rights reserved. No part of this publication may be
21、reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.698.4 (03/2018) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventio
22、ns 3 6 Classification of optical interfaces 3 6.1 Applications 3 6.2 Reference points . 3 6.3 Nomenclature . 4 7 Transverse compatibility 4 8 Parameter definitions 5 8.1 General information 6 8.2 Interface at point SS or MPI-SM. 6 8.3 Optical path from point MPI-SM to RS or SS to MPI-RM 9 8.4 Interf
23、ace at point RS or MPI-RM 10 9 Parameter values . 10 10 Optical safety considerations 15 11 Method of operation . 15 11.1 Optical frequency setting during tuning . 15 11.2 Output power setting during tuning 21 Appendix I Output power setting during tuning . 22 Rec. ITU-T G.698.4 (03/2018) 1 Recommen
24、dation ITU-T G.698.4 Multichannel bi-directional DWDM applications with port agnostic single-channel optical interfaces 1 Scope The purpose of this Recommendation is to provide optical interface specifications towards the realization of transversely compatible bidirectional dense wavelength division
25、 multiplexing (DWDM) systems, primarily intended for metro applications. The tail-end equipment (TEE) transmitters have the capability to automatically adapt their DWDM channel frequency to the optical demultiplexer/optical multiplexer (OD/OM) or optical add/drop multiplexer (OADM) port they are con
26、nected to using feedback from the head-end equipment (HEE) via the head-to-tail message channel (HTMC). This Recommendation defines and provides values for optical interface parameters of point-to-point DWDM applications on single-mode optical fibres through the use of the “black link“ approach with
27、 both of the propagation directions sharing the same optical fibre end-to-end. For the applications in this version of the Recommendation, the black-link does not contain optical amplifiers. This Recommendation describes bidirectional DWDM systems that include the following features: channel frequen
28、cy spacing: 50 GHz and 100 GHz; bit rate of signal channel: Up to 10 Gbit/s; transmission distance: Up to 20 km; capacity: Up to 40 bidirectional channels. Specifications are organized according to application codes. 2 References The following ITU-T Recommendations and other references contain provi
29、sions which, 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 possibi
30、lity of applying 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 Recommend
31、ation. ITU-T G.652 Recommendation ITU-T G.652 (2016), Characteristics of a single-mode optical fibre and cable. ITU-T G.664 Recommendation ITU-T G.664 (2012), Optical safety procedures and requirements for optical transmission systems. ITU-T G.671 Recommendation ITU-T G.671 (2012), Transmission char
32、acteristics of optical components and subsystems. ITU-T G.694.1 Recommendation ITU-T G.694.1 (2012), Spectral grids for WDM applications: DWDM frequency grid. ITU-T G.698.1 Recommendation ITU-T G.698.1 (2009), Multichannel DWDM applications with single-channel optical interfaces. ITU-T G.957 Recomme
33、ndation ITU-T G.957 (2006), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. 2 Rec. ITU-T G.698.4 (03/2018) ITU-T G.959.1 Recommendation ITU-T G.959.1 (2016), Optical transport network physical layer interfaces. IEC 60825-1 IEC 60825-1:2014, Safety of lase
34、r products Part 1: Equipment classification and requirements. IEC 60825-2 IEC 60825-2:2010, Safety of laser products Part 2: Safety of optical fibre communication systems (OFCS). IEEE 802.3 IEEE 802.3-2015, IEEE Standard for Ethernet. 3 Definitions 3.1 Terms defined elsewhere This Recommendation use
35、s the following terms defined elsewhere: 3.1.1 Terms defined in ITU-T G.671: channel insertion loss; channel spacing; dense wavelength division multiplexing (DWDM); differential group delay; reflectance; ripple. 3.1.2 Term defined in ITU-T G.694.1: frequency grid. 3.1.3 Terms defined in ITU-T G.957:
36、 receiver sensitivity; transverse compatibility. 3.1.4 Terms defined in ITU-T G.959.1: optical tributary signal; optical tributary signal class NRZ 10G. 3.2 Terms defined in this Recommendation None. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: BER
37、Bit Error Ratio DWDM Dense Wavelength Division Multiplexing HEE Head-End Equipment HTMC Head-to-Tail Message Channel LOS Loss of Signal MPI-RM Multichannel reference point at the head-end aggregate input MPI-SM Multichannel reference point at the head-end aggregate output Rec. ITU-T G.698.4 (03/2018
38、) 3 NRZ Non-Return to Zero OADM Optical Add-Drop Multiplexer OD Optical Demultiplexer OM Optical Multiplexer RS Single-channel reference point at the DWDM network element tributary output SS Single-channel reference point at the DWDM network element tributary input TEE Tail-End Equipment THMC Tail t
39、o Head Message Channel TOM Type of Message 5 Conventions None. 6 Classification of optical interfaces 6.1 Applications This Recommendation provides the physical layer parameters and values for single-channel and multichannel interfaces of DWDM multichannel optical systems in physical point-to-point
40、single fibre applications where the tail-end transmitters have the capability to automatically adapt their DWDM channel frequency. These DWDM systems are primarily intended to be used in metropolitan area networks for a variety of clients, services and protocols. The specification method in this Rec
41、ommendation uses a “black link“ approach which means that optical interface parameters for only (single-channel) optical tributary signals are specified at the tail-end equipment (TEE). Additional specifications are provided for the black link parameters such as maximum attenuation, chromatic disper
42、sion, ripple and polarization mode dispersion. This approach enables transverse compatibility at the single-channel point using a direct wavelength-multiplexing configuration and also transverse compatibility at the head-end multichannel point as shown in Figure 6-1. 6.2 Reference points Figure 6-1
43、Linear “black link“ approach 4 Rec. ITU-T G.698.4 (03/2018) The system architecture comprises a head-end, connecting to the TEE through a black link. The head-end houses a set of transmitters and receivers and an OD/OM. A single bidirectional fibre is used to connect the head-end to the passive OD/O
44、M as well as optional OADMs. Connection between OD/OM or OADMs and TEE is also bidirectional. The OD/OM is considered to be part of the black link. The TEE transmitters have the capability to automatically adapt their DWDM channel frequency to the OD/OM or OADM port they are connected to. The refere
45、nce points in Figure 6-1are defined as follows: MPI-SM is a multichannel reference point at the head-end aggregate output; MPI-RM is a multichannel reference point at the head-end aggregate input; SS is a single-channel reference point at the TEE output; RS is a single-channel reference point at the
46、 TEE input. At the MPI-SM interface, multichannel data signals are transmitted by the head-end. At the RS interface a single channel data signal passes through towards the TEE. At the SS interface, a single channel signal is transmitted by the TEE whose wavelength is appropriate to that of the conne
47、cted OD/OM or OADM port. At the MPI-RM interface, a multichannel signal is received by the head-end. 6.3 Nomenclature The application code notation is constructed as follows: ADcW-y-tz where: AD: is the indicator of metro DWDM applications with port agnostic TEE. c: is the channel spacing in GHz. W:
48、 is a letter indicating the span distance, such as: S indicating short-haul; y: indicates the highest class of optical tributary signal supported: 2 indicating NRZ 10G; t: indicates the configuration supported by the application code. In the current version of this Recommendation, the only value use
49、d is: D indicating that the black link does not contain any optical amplifiers. z: indicates the fibre types. In the current version of this Recommendation, the only value used is: 2 indicating ITU-T G.652 fibre. 7 Transverse compatibility This Recommendation specifies parameters in order to enable transverse (i.e., multivendor) compatible line systems for point-to-point applications at single-channel reference points SS and RS and multichannel reference points M
