1、 International Telecommunication Union ITU-T G.987TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (06/2012) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Optical line systems for local and access networks 10-Gigabit-capable passive op
2、tical network (XG-PON) systems: Definitions, abbreviations and acronyms Recommendation ITU-T G.987 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 CA
3、RRIER-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 METALLIC LINES G.400G.449 COORDINATIO
4、N OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION 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.9
5、10G.919 Digital sections at hierarchical bit rates based 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 an
6、d digital transmission systems for customer access to ISDN G.960G.969 Optical fibre submarine cable systems G.970G.979 Optical line systems for local and access networks G.980G.989Access networks G.990G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 T
7、RANSMISSION 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.987 (06/2012) i Recommendation ITU-T G.987 10-G
8、igabit-capable passive optical network (XG-PON) systems: Definitions, abbreviations and acronyms Summary Recommendation ITU-T G.987 contains the common definitions, acronyms, abbreviations and conventions of the ITU-T G.987.x-series Recommendations. History Edition Recommendation Approval Study Grou
9、p 1.0 ITU-T G.987 2010-01-29 15 2.0 ITU-T G.987 2010-10-07 15 3.0 ITU-T G.987 2012-06-13 15 ii Rec. ITU-T G.987 (06/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (
10、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 worldwide basis. The World Telecommunicati
11、on 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 Resolution 1. In some areas of inf
12、ormation 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 administration and a recognized operating ag
13、ency. 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 provisions are met. The words “shall“ or so
14、me 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 RIGHTS ITU draws attention to the possibility that the practice or
15、 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 the Recommendation development p
16、rocess. 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 information and are therefore stro
17、ngly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 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.987 (06/2012) iii Table of Contents Page 1 Scope 1 2 Referenc
18、es. 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Optical access architecture terms . 2 3.3 Optical parameters, power and loss budget terms 3 3.4 Transmission convergence layer terms 4 4 Abbreviations and acronyms 6 5 Conventions 12 5.1 Optical access concepts 12 5.2 Power and loss budget para
19、meters . 13 5.3 Sensitivity and overload in the presence of FEC 14 5.4 Reach and distance . 14 5.5 Use of the term PON 15 5.6 Use of the term ODN 15 5.7 Use of the terms ONU and ONT 16 5.8 Use of the terms T-CONT and Alloc-ID 16 5.9 Use of the terms bandwidth assignment and bandwidth allocation . 17
20、 Bibliography. 18 Rec. ITU-T G.987 (06/2012) 1 Recommendation ITU-T G.987 10-Gigabit-capable passive optical network (XG-PON) systems: Definitions, abbreviations and acronyms 1 Scope This Recommendation contains the common definitions, acronyms, abbreviations and conventions of the ITU-T G.987.x ser
21、ies Recommendations. 2 References The following ITU-T Recommendations and other references contain provisions 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 a
22、re 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 listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a do
23、cument within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T G.902 Recommendation ITU-T G.902 (1995), Framework Recommendation on functional access networks (AN) Architecture and functions, access types, management and service node aspects. ITU
24、-T G.987.1 Recommendation ITU-T G.987.1 (2010), 10 Gigabit-capable passive optical networks (XG-PON): General requirements. ITU-T G.987.2 Recommendation ITU-T G.987.2 revised (2010), 10 Gigabit-capable passive optical networks (XG-PON): Physical media dependent (PMD) layer specification. ITU-T G.987
25、.3 Recommendation ITU-T G.987.3 (2010), 10 Gigabit-capable passive optical networks (XG-PON): Transmission convergence (TC) layer specification. ITU-T G.988 Recommendation ITU-T G.988 (2010), ONU management and control interface (OMCI) specification. 3 Definitions 3.1 Terms defined elsewhere This Re
26、commendation uses the following terms defined elsewhere: 3.1.1 access network (AN) ITU-T G.902: An implementation comprising those entities (such as cable plant, transmission facilities, etc.) which provide the required transport bearer capabilities for the provision of telecommunications services b
27、etween a service node interface (SNI) and each of the associated user-network interfaces (UNI). 3.1.2 Ethernet LAN service (E-LAN) b-MEF 6.1: An Ethernet service type that is based on a multipoint-to-multipoint Ethernet virtual connection. 3.1.3 Ethernet line service (E-Line) b-MEF 6.1: An Ethernet
28、service type that is based on a point-to-point Ethernet virtual connection. 3.1.4 Ethernet tree service (E-Tree) b-MEF 6.1: An Ethernet service type that is based on a rooted-multipoint Ethernet virtual connection. 2 Rec. ITU-T G.987 (06/2012) 3.1.5 Ethernet virtual connection (EVC) b-MEF 6.1: An as
29、sociation of UNIs to which the exchange of service frames is limited. 3.1.6 service node (SN) ITU-T G.902: A network element that provides access to various switched and/or permanent telecommunication services. 3.1.7 service node interface (SNI) ITU-T G.902: An interface which provides customer acce
30、ss to a service node. 3.1.8 user-network interface (UNI) b-ITU-T I.112: The interface between the terminal equipment and a network termination at which interface the access protocols apply. 3.1.9 1:1 VLAN b-DSLF TR-101: A VLAN forwarding paradigm involving a one-to-one mapping between user port and
31、VLAN. The uniqueness of the mapping is maintained in the access node and across the aggregation network. 3.1.10 N:1 VLAN b-DSLF TR-101: A VLAN forwarding paradigm involving many-to-one mapping between user ports and VLAN. The user ports may be located in the same or different access nodes. 3.2 Optic
32、al access architecture terms This Recommendation defines the following terms: 3.2.1 gigabit-capable passive optical network (G-PON): A PON system supporting transmission rates in excess of 1.0 Gbit/s in at least one direction, and implementing the suite of protocols specified in the ITU-T G.984.x se
33、ries Recommendations. 3.2.2 next generation PON (NG-PON): In the context of ITU-T standards development activity, a generic term referencing the PON system evolution beyond G-PON. The concept of NG-PON currently includes NG-PON1, where the ODN is maintained from B-PON and G-PON, and NG-PON2, where a
34、 redefinition of the ODN is allowed from that defined in B-PON and G-PON. 3.2.3 optical access network (OAN): A part of an access network whose network elements are interconnected by optical communication channels. NOTE An OAN may or may not extend all the way to the UNI, so that the user-side inter
35、face of the OAN does not necessarily coincide with the UNIs of the AN. 3.2.4 optical distribution network (ODN): A point-to-multipoint optical fibre infrastructure. A simple ODN is entirely passive and is represented by a single-rooted point-to-multipoint tree of optical fibres with splitters, combi
36、ners, filters, and possibly other passive optical components. A composite ODN consists of two or more passive segments interconnected by active devices, each of the segments being either an optical trunk line segment or an optical distribution segment. A passive optical distribution segment is a sim
37、ple ODN itself. Two ODNs with distinct roots can share a common subtree. 3.2.5 optical distribution segment (ODS): A simple ODN, that is, a point-to-multipoint optical fibre infrastructure that is entirely passive and is represented by a single-rooted tree of optical fibres with splitters, combiners
38、, filters, and possibly other passive optical components. 3.2.6 optical line termination (OLT): A network element in an ODN-based optical access network that terminates the root of at least one ODN and provides an OAN SNI. 3.2.7 optical network terminal (ONT): An ONU supporting a single subscriber.
39、3.2.8 optical network unit (ONU): A network element in an ODN-based optical access network that terminates a leaf of the ODN and provides an OAN UNI. 3.2.9 optical trunk line (OTL): A passive point-to-point segment of a composite ODN. Rec. ITU-T G.987 (06/2012) 3 3.2.10 passive optical network (PON)
40、 system: A combination of network elements in an ODN-based optical access network that includes an OLT and multiple ONUs and implements a particular coordinated suite of physical medium dependent layer, transmission convergence layer, and management protocols. 3.2.11 10-gigabit-capable passive optic
41、al network (XG-PON): A PON system supporting nominal transmission rates on the order of 10 Gbit/s in at least one direction, and implementing the suite of protocols specified in the ITU-T G.987.x series Recommendations. XG-PON is a subclass of NG-PON1. 3.2.12 XG-PON1: A variant of XG-PON system that
42、 operates at a nominal line rate of 10 Gbit/s downstream and 2.5 Gbit/s upstream. 3.2.13 XG-PON2: A variant of XG-PON system that operates at a nominal line rate of 10 Gbit/s downstream and upstream. 3.3 Optical parameters, power and loss budget terms 3.3.1 attenuation: The total relative optical po
43、wer loss of an optical signal propagating through the ODN. Attenuation is caused by absorption and scattering of light in the fibre (caused by fibre impurities and imperfections, fluctuations of the refractive index, material dispersion), as well as connectors, splices, splitters, wavelength coupler
44、s, attenuators, and other passive optical components. 3.3.2 differential fibre distance: The absolute difference between the fibre distances of two particular ONUs connected to the same OLT PON interface. 3.3.3 dispersion: A physical phenomenon comprising the dependence of the phase or group velocit
45、y of a light wave in the medium on its propagation characteristics such as optical frequency (wavelength) or polarization mode. 3.3.4 dynamic range: An optical receiver characteristic that represents the difference between the worst-case sensitivity (i.e., maximum over the operating conditions) and
46、the worst-case overload (i.e., minimum over the operating conditions), and is usually expressed as a ratio of the former to the latter. 3.3.5 extinction ratio: With respect to a digital signal generated by an optical source (laser diode), the ratio of the two optical power levels corresponding to th
47、e high and low intensities of light emission. 3.3.6 fibre distance: The overall length of fibre (and, if applicable, equivalent fibre runs representing delay-inducing components) between the R/S and S/R reference points. 3.3.7 mean optical launch power: An optical transmitter characteristic expressi
48、ng the average optical power of an optical signal transmitted into the fibre and carrying a given digital sequence. When specified as a range, the minimum mean launch power provides the power level that the transmitter should guarantee at all times, and the maximum mean launch power provides the pow
49、er level that the transmitter should never exceed. When applied to burst mode transmission, the term pertains to the time interval during which the transmitter is fully active, and excludes possible starting and ending transient behaviour. 3.3.8 nominal line rate: The total number of bits that can be physically transferred per unit of time over a communication link. Nominal line rate accounts for useful data as well as for all possible protocol overheads and necessarily exceeds the effective data rate on any given
