1、 International Telecommunication Union ITU-T G.984.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2008) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Optical line systems for local and access networks Gigabit-capable passive opt
2、ical networks (GPON): General characteristics Recommendation ITU-T G.984.1 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 SYSTE
3、MS 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 COORDINATION OF RADIOTELEPHONY AND
4、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.910G.919 Digital sections
5、 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 and digital transmission s
6、ystems 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.989 Access networks G.990G.999 QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS
7、G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.984.1 (03/2008) i Recommendation ITU-T G.984.1 Gigabit-capable passive optical net
8、works (GPON): General characteristics Summary Recommendation ITU-T G.984.1 describes a flexible optical fibre access network capable of supporting the bandwidth requirements of business and residential services and covers systems with nominal line rates of 2.4 Gbit/s in the downstream direction and
9、1.2 Gbit/s and 2.4 Gbit/s in the upstream direction. Both symmetrical and asymmetrical (upstream/downstream) gigabit-capable passive optical network (GPON) systems are described. This Recommendation proposes the general characteristics for GPON based on operators service requirements. Source Recomme
10、ndation ITU-T G.984.1 was approved on 29 March 2008 by ITU-T Study Group 15 (2005-2008) under Recommendation ITU-T A.8 procedure. ii Rec. ITU-T G.984.1 (03/2008) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, info
11、rmation 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 wo
12、rldwide 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
13、 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 this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication admi
14、nistration 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 provi
15、sions 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 RIGHTS ITU draws attention t
16、o 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 evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outsi
17、de 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 be required to implement this Recommendation. However, implementers are cautioned that this may not represent the lat
18、est information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2009 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.984.1 (03/2008) iii CON
19、TENTS 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 3 5 Architecture of the optical access network. 4 5.1 Network architecture 4 5.2 Reference configuration . 5 6 Services, user-network interface
20、and service node interface 6 6.1 Services. 6 6.2 User-network interface (UNI) and service node interface (SNI) . 7 7 Bit rate 7 8 Logical reach 7 9 Physical reach . 7 10 Differential fibre distance. 7 11 Maximum mean signal transfer delay. 7 12 Split ratio 7 13 Service overlay . 8 14 Protection on t
21、he PON section 8 14.1 Possible switching types. 8 14.2 Possible duplex GPON configurations and characteristics 9 14.3 Requirements 10 14.4 Required information fields for OAM frame . 11 15 Security. 11 Appendix I Examples of GPON services, architectures and service protocol stacks. 12 I.1 Services,
22、UNIs and SNIs 12 I.2 Typical system architectures 14 I.3 Service protocol stacks. 16 Appendix II External access network backup. 27 Appendix III Dual-parenting resilience 30 Bibliography. 32 Rec. ITU-T G.984.1 (03/2008) 1 Recommendation ITU-T G.984.1 Gigabit-capable passive optical networks (GPON):
23、General characteristics 1 Scope This Recommendation addresses the general characteristics of gigabit-capable passive optical network (GPON) systems in order to guide and motivate the physical layer and the transmission convergence layer specifications. The general characteristics include examples of
24、 services, user-network interfaces (UNIs) and service node interfaces (SNIs) that are requested by network operators. Also, this Recommendation shows the principle deployment configuration. As much as possible, this Recommendation maintains characteristics from ITU-T G.982 and ITU-T G.983.x-series R
25、ecommendations. This is to promote backward-compatibility with existing optical distribution networks (ODNs) that complies with those Recommendations. GPON systems are characterized, in general, by an optical line termination (OLT) system and an optical network unit (ONU) or optical network terminat
26、ion (ONT) with a passive optical distribution network (ODN) interconnecting them. There is, in general, a one-to-many relationship between the OLT and the ONU/ONTs, respectively. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this
27、 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 applying the most recent editi
28、on 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-T G.652 Recommendation ITU-
29、T G.652 (2003), Characteristics of a single-mode optical fibre cable. ITU-T G.808.1 Recommendation ITU-T G.808.1 (2006), Generic protection switching Linear trail and subnetwork protection. ITU-T G.902 Recommendation ITU-T G.902 (1995), Framework Recommendation on functional access networks (AN) Arc
30、hitecture and functions, access types, management and service node aspects. ITU-T G.982 Recommendation ITU-T G.982 (1996), Optical access networks to support services up to the ISDN primary rate or equivalent bit rates. ITU-T G.983.1 Recommendation ITU-T G.983.1 (1998), Broadband optical access syst
31、ems based on Passive Optical Networks (PON). ITU-T G.983.2 Recommendation ITU-T G.983.2 (2002), ONT management and control interface specification for B-PON. ITU-T G.983.3 Recommendation ITU-T G.983.3 (2001), A broadband optical access system with increased service capability by wavelength allocatio
32、n. ITU-T G.984.2 Recommendation ITU-T G.984.2 (2003), Gigabit-capable Passive Optical Networks (GPON): Physical Media Dependent (PMD) layer specification. ITU-T G.984.3 Recommendation ITU-T G.984.3 (2008), Gigabit-capable Passive Optical Networks (GPON): Transmission convergence layer specification.
33、 2 Rec. ITU-T G.984.1 (03/2008) ITU-T G.984.4 Recommendation ITU-T G.984.4 (2008), Gigabit-capable Passive Optical Networks (GPON): ONT management and control interface specification. ITU-T G.984.5 Recommendation ITU-T G.984.5 (2007), Gigabit-capable Passive Optical Networks (GPON): Enhancement band
34、. ITU-T I.112 Recommendation ITU-T I.112 (1993), Vocabulary of terms for ISDNs. 3 Definitions This Recommendation makes frequent use of the terms defined in ITU-T G.983.1 and ITU-T G.983.3; some terms have been added. For convenience, the main definitions related to the GPON service requirements are
35、 reported in this clause. 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 service node interface (SNI): ITU-T G.902 3.1.2 user-network interface (UNI): ITU-T I.112 3.2 Terms defined in this Recommendation This Recommendation defines the following ter
36、ms: 3.2.1 adaptation function (AF): AF is additional equipment and/or function to change an ONT/ONU subscriber-side interface into the UNI. Functions of AF depend on the ONT/ONU subscriber-side interface and UNI interface. AF is also used to change an OLT network interface into the SNI interface tha
37、t is required by an operator. 3.2.2 differential fibre distance: An OLT is connected to several ONU/ONTs. The differential fibre distance is the difference in the distance between the nearest and furthest ONU/ONT from the OLT. 3.2.3 logical reach: Logical reach is defined as the maximum distance tha
38、t can be achieved for a particular transmission system, regardless of the optical budget. 3.2.4 mean signal transfer delay: The mean signal transfer delay is the average of the upstream and downstream delay values between reference points; this value is determined by measuring round-trip delay and t
39、hen dividing by 2. 3.2.5 optical access network (OAN): The OAN is the set of access links sharing the same network-side interfaces and supported by optical access transmission systems. The OAN may include a number of ODNs connected to the same OLT. 3.2.6 optical distribution network (ODN): In the PO
40、N context, a tree of optical fibres in the access network, supplemented with power or wavelength splitters, filters or other passive optical devices. 3.2.7 optical line termination (OLT): A device that terminates the common (root) endpoint of an ODN, implements a PON protocol, such as that defined b
41、y ITU-T G.984, and adapts PON PDUs for uplink communications over the provider service interface. The OLT provides management and maintenance functions for the subtended ODN and ONUs. 3.2.8 optical network termination (ONT): A single subscriber device that terminates any one of the distributed (leaf
42、) endpoints of an ODN, implements a PON protocol, and adapts PON PDUs to subscriber service interfaces. An ONT is a special case of an ONU. Rec. ITU-T G.984.1 (03/2008) 3 3.2.9 optical network unit (ONU): A generic term denoting a device that terminates any one of the distributed (leaf) endpoints of
43、 an ODN, implements a PON protocol, and adapts PON PDUs to subscriber service interfaces. In some contexts, an ONU implies a multiple-subscriber device. 3.2.10 physical reach: Physical reach is defined as the maximum physical distance that can be achieved for a particular transmission system. 3.2.11
44、 service: Service is defined as a network service required by operators. Service is described by a name that is clearly recognized by everyone, regardless of whether it is a frame structure name or a general name. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and
45、acronyms: AF Adaptation Function BRI Basic Rate Interface DSL Digital Subscriber Line FTTB Fibre to the Building FTTC Fibre to the Curb FTTCab Fibre to the Cabinet FTTH Fibre to the Home ISDN Integrated Services Digital Network LT Line Terminal MDU Multi-Dwelling Unit NT Network Termination OAM Oper
46、ation, Administration and Maintenance OAN Optical Access Network ODN Optical Distribution Network OLT Optical Line Termination ONT Optical Network Termination ONU Optical Network Unit OpS Operations System PDH Plesiochronous Digital Hierarchy PON Passive Optical Network POTS Plain Old Telephone Serv
47、ice PRI Primary Rate Interface PSTN Public Switched Telephone Network SDH Synchronous Digital Hierarchy SN Serial Number SNI Service Node Interface TC Transmission Convergence 4 Rec. ITU-T G.984.1 (03/2008) UNI User-Network Interface VOD Video On Demand WDM Wavelength Division Multiplexing 5 Archite
48、cture of the optical access network 5.1 Network architecture The optical section of a local access network system can be either active or passive and its architecture can be either point-to-point or point-to-multipoint. Figure 1 shows the architectures considered, which range from fibre to the home
49、(FTTH), through fibre to the building/curb (FTTB/C) to fibre to the cabinet (FTTCab). The optical access network (OAN) is common to all architectures shown in Figure 1, hence the commonality of this system has the potential to generate large worldwide volumes. G.984.1_F1FibreFibreFibreCopperCopperAccess networkHomenetworkUNI SNIONU Optical Network UnitONT Optical Network TerminationOLT Optical Line TerminationNT Network TerminationFTTCabFTTHONTNTNTONUONUOLTFTTB/CFigure 1 Network architecture The differences of t
