1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T G.983.5TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2002) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Optical line systems for local and access networks A broadband optical access
2、system with enhanced survivability ITU-T Recommendation G.983.5 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.2
3、99 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 LINE TELEPH
4、ONY G.450G.499 TESTING EQUIPMENTS G.500G.599 TRANSMISSION MEDIA 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 sy
6、stems 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 G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DIGITAL TERMINAL EQUI
7、PMENTS G.7000G.7999 DIGITAL NETWORKS G.8000G.8999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.983.5 (01/2002) i ITU-T Recommendation G.983.5 A broadband optical access system with enhanced survivability Summary This Recommendation describes flexible access ne
8、tworks using optical fibre technology based on ITU-T Rec. G.983.1. Specifically, it describes the functions that extend ITU-T Rec. G.983.1 to enable survivability-protection enhancements for the delivery of highly reliable services. It describes B-PON survivability architectures, protection performa
9、nce criteria, and protection-switching criteria and protocols. Source ITU-T Recommendation G.983.5 was prepared by ITU-T Study Group 15 (2001-2004) and approved under the WTSA Resolution 1 procedure on 6 January 2002. ii ITU-T Rec. G.983.5 (01/2002) FOREWORD The International Telecommunication Union
10、 (ITU) is the United Nations specialized agency in the field of telecommunications. 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 sta
11、ndardizing 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, produce Recommendations on these topics. The approval of ITU-T Recommendations is
12、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 this Recommendation, the expression “Administration“ is used for conciseness to i
13、ndicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU 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 concer
14、ning 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 approval of this Recommendation, ITU had received notice of intellectual property, protected by patents
15、, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2002 All rights reserved. No part of this publication may be reproduced, by any me
16、ans whatsoever, without the prior written permission of ITU. TU-T Rec. G.983.5 (01/2002) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Abbreviations 2 4 Definitions 4 5 Architecture and requirements for a protected optical access network 5 5.1 Architecture and requirements . 5 5.1.1 Service categori
17、es. 5 5.1.2 Background and requirements 5 5.2 Reference configuration . 8 5.3 Functional blocks 8 5.4 ONU functional block 8 5.4.1 Optical Distribution Network (ODN) interface 8 5.4.2 Multiplexing . 9 5.4.3 User Port. 9 5.4.4 ONU Powering . 9 5.4.5 ODN interface switch. 9 5.5 OLT functional block .
18、9 5.6 Optical Distribution Network (ODN) functional block 11 5.6.1 Passive optical elements. 11 5.6.2 Optical interfaces 11 6 Services. 13 7 User Network Interface and Service Node Interface 13 8 Optical network survivability requirements . 13 8.1 Layer structure of the B-PON survivability optical n
19、etwork . 13 8.2 Physical medium dependent layer requirements for B-PON . 15 8.3 Additional TC-layer requirements for B-PON survivability 15 8.3.1 Duplex PON link identification 15 8.3.2 Additional messages in the PLOAM channel for survivability 16 8.3.3 Message formats. 16 8.4 Ranging Method . 17 8.
20、5 Protection switching . 17 8.5.1 PON Protection function 17 8.5.2 Protocols. 19 8.5.3 Switching criteria 19 8.5.4 Performance 20 iv ITU-T Rec. G.983.5 (01/2002) Page 9 Operations Administration and Maintenance (OAM) functionality. 22 10 Performance 22 11 Environmental condition 22 12 Safety 22 Anne
21、x A Fast switching protocol for the B-PON access network . 22 A.1 Survivability Architecture 22 A.1.1 1:1 architecture (required) 22 A.1.2 1+1 Architecture (optional) 23 A.2 MSP bytes. 24 A.2.1 K1 byte . 24 A.2.2 K1 byte generation rules. 24 A.2.3 Revertive/non-revertive modes 24 A.2.4 K2 byte . 25
22、A.2.5 Control of the upstream switch in the ONU and the downstream switch in the OLT 25 A.2.6 Transmission and acceptance of MSP Bytes 25 A.3 MSP commands 25 A.4 Switching Sequence 25 A.4.1 1:1 bidirectional operation with non-revertive mode . 25 A.4.2 1:1 bidirectional operation with revertive mode
23、 43 A.4.3 1+1 bidirectional operation with non-revertive mode 46 A.4.4 1+1 bidirectional operation with revertive mode . 49 ITU-T Rec. G.983.5 (01/2002) 1 ITU-T Recommendation G.983.5 A broadband optical access system with enhanced survivability 1 Scope This Recommendation describes the extended fun
24、ctions for B-PON systems defined in ITU-T Rec. G.983.1 to enable protection functions. It is based on Appendix IV/G.983.1. In particular, it focuses on the protection-configuration types B and C described in that appendix. This Recommendation discusses a number of protection feature and function cho
25、ices and provides the necessary specifications in the PON layer to implement these choices. These include guidelines on performance objectives (for example, switching and detection time), application functionality (for example, revertive mode, non-revertive mode, extra traffic support, automatic swi
26、tching, and forced switching), switching criteria and switching protocols (1+1, 1:1, 1:N, bidirectional and unidirectional mechanisms). This Recommendation considers protection enhancements for the delivery of highly reliable services for a variety of B-PON network scenarios, including Fibre to the
27、Cabinet (FTTCab) and Fibre to the Office (FTTO). 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 Recommend
28、ations 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 listed below. A list of the currently valid ITU-T Recommendations is regularly pub
29、lished. 1 ITU-T Recommendation G.652 (2000), Characteristics of a single-mode optical fibre cable. 2 ITU-T Recommendation G.671 (2001), Transmission characteristics of optical components and subsystems. 3 ITU-T Recommendation G.783 (2000), Characteristics of synchronous digital hierarchy (SDH) equip
30、ment functional blocks. 4 ITU-T Recommendation G.841 (1998), Types and characteristics of SDH network protection architectures. 5 ITU-T Recommendation G.902 (1995), Framework recommendation on functional access networks (AN) Architecture and functions, access types, management and service node aspec
31、ts. 6 ITU-T Recommendation G.957 (1999), Optical interfaces for equipment and systems relating to the synchronous digital hierarchy. 7 ITU-T Recommendation G.958 (1994), Digital line systems based on the synchronous digital hierarchy for use on optical fibre cables. 8 ITU-T Recommendation G.982 (199
32、6), Optical access networks to support services up to the ISDN primary rates or equivalent bit rates. 9 ITU-T G.983.1 (1998), Broadband optical access systems based on Passive Optical Networks (PON). 2 ITU-T Rec. G.983.5 (01/2002) 10 ITU-T G.983.2 (2000), The ONT management and control interface spe
33、cification for ATM PON. 11 ITU-T I.321 (1991), B-ISDN protocol reference model and its application. 12 ITU-T I.326 (1995), Functional architecture of transport networks based on ATM. 13 ITU-T I.356 (2000), B-ISDN ATM layer cell transfer performance. 14 ITU-T I.361 (1999), B-ISDN ATM layer specificat
34、ion. 15 ITU-T I.432.1 (1999), B-ISDN user-network interface Physical layer specification: General characteristics. 16 ITU-T I.610 (1999), B-ISDN operation and maintenance principles and functions. 17 ITU-T I.732 (2000), Functional characteristics of ATM equipment. 3 Abbreviations This Recommendation
35、 uses the following abbreviations: AF Adaptation Function APS Automatic Protection Switching ATM Asynchronous Transfer Mode BER Bit Error Ratio BIP Bit Interleaved Parity B-ISDN Broadband Integrated Services Digital Network B-PON Broadband Passive Optical Network CID Consecutive Identical Digit CPE
36、Cell Phase Error CRC Cyclic Redundancy Check DSL Digital Subscriber Line E/O Electrical/Optical FTTB/C Fibre to the Building/Curb FTTCab Fibre to the Cabinet FTTH Fibre to the Home FTTO Fibre to the Office HEC Header Error Control IEC International Electrotechnical Commission ISDN Integrated Service
37、s Digital Network LAN Local Area Network LCD Loss of Cell Delineation LCF Laser Control Field LSB Least Significant Bit LT Line Terminal MAC Media Access Control ITU-T Rec. G.983.5 (01/2002) 3 MSB Most Significant Bit MSP Multiplex Section Protection NT Network Termination OAM Operation, Administrat
38、ion and Maintenance OAN Optical Access Network ODF Optical Distribution Frame ODN Optical Distribution Network OLT Optical Line Termination ONT Optical Network Termination ONU Optical Network Unit OpS Operations System PLOAM Physical Layer OAM PON Passive Optical Network PRBS Pseudo-Random Bit Seque
39、nce PST PON Section Trace PSTN Public Switched Telephone Network QoS Quality of Service RAU Request Access Unit RMS Root Mean Square SD Signal Degrade SDH Synchronous Digital Hierarchy SF Signal Fail SN Serial Number SNI Service Node Interface SPC Service Port Function TC Transmission Convergence TD
40、MA Time Division Multiple Access UI Unit Interval UNI User Network Interface UPC Usage Parameter Control UPF User Port Function VC Virtual Channel VoD Video on Demand VP Virtual Path VPI Virtual Path Identifier WDM Wavelength Division Multiplexing 4 ITU-T Rec. G.983.5 (01/2002) 4 Definitions This Re
41、commendation defines the following terms: 4.1 1:1 protection: A system of 1:1 protection configuration carries traffic in the working equipment while the protection equipment stands by without serving any traffic. The 1:1 protection configuration is a special case of the more general 1:N protection
42、where the protection equipment is shared among N sets of working equipment. 4.2 1+1 protection: A system of 1+1 protection configuration carries identical traffic in both working and protection equipment. 4.3 X:N protection architecture: A system of X:N protection architecture offers X protection PO
43、Ns for N working PONs, where some or all of the protected ONUs on the working PONs can be connected to any of the X protection PONs. 4.4 bidirectional protection: Upon detecting a failure of its working equipment, a system of bidirectional protection configuration requires acknowledgement from the f
44、ar-end protection equipment before switching to the protection equipment. 4.5 unidirectional protection: A system of unidirectional protection configuration can switch to protection equipment once it detects failure in its working equipment. 4.6 churning: Churning is a function that can be applied t
45、o the downstream user data from an OLT to its ONUs. Churning provides the necessary function of data scrambling and offers a low level of protection for data confidentiality. It is installed at the TC layer of the B-PON system and can be activated for point-to-point downstream connections. 4.7 duple
46、x working: Bidirectional communication using a different wavelength for each direction of transmission over a single fibre. 4.8 extra traffic: Lower priority traffic with respect to that being carried by the working entity. It is carried over the protection entity while the working entity is active.
47、 The extra traffic is not protected, i.e. when the protection entity is required to protect the traffic that is being carried over the working entity (due to a failure or forced/manual switch operation), the extra traffic is pre-empted. 4.9 grant: A grant is a short downstream message giving permiss
48、ion to a specific ONU to transmit an upstream cell. The OLT controls the distribution of grants to the ONUs and ensures good use of the upstream channel without data collisions. 4.10 mean signal transfer delay: The average upstream and downstream values between reference points “V“ and “T“, a given
49、value is determined by measuring round-trip delay, then dividing by 2. 4.11 non-revertive: A protection configuration is non-revertive if the system does not switch back. 4.12 Optical Access Network (OAN): 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. 4.13 Optical Distribution Network (ODN): An ODN provides the optical transmission means from the OLT towards the users, and vice versa. It uti
