1、 International Telecommunication Union ITU-T Series GTELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 45(05/2009) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS GPON power conservation ITU-T G-series Recommendations Supplement 45 ITU-T G-SERIES RECOMMENDATIONS TRANS
2、MISSION 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 OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.39
3、9 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 MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQ
4、UIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER
5、 TRANSPORT ASPECTS G.8000G.8999ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. G series Supplement 45 (05/2009) i Supplement 45 to ITU-T G-series Recommendations GPON power conservation Summary Supplement 45 to ITU-T G-series Recommendations conso
6、lidates the various GPON power-saving proposals in order to facilitate their consideration and comparative analysis from the perspective of the requirements satisfiability, on the one hand, and the overall system impact, on the other hand. This Supplement is formatted as a white paper encompassing t
7、he summary of the requirements gathering effort, the specification of the wide spectrum of potential solutions as well as their comparative analysis. Source Supplement 45 to ITU-T G-series Recommendations was agreed on 15 May 2009 by ITU-T Study Group 15 (2009-2012). ii G series Supplement 45 (05/20
8、09) FOREWORD The International 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
9、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 Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study
10、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 fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis wi
11、th ISO and IEC. NOTE In this publication, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this publication is voluntary. However, the publication may contain certain mandatory provisions (t
12、o ensure e.g., interoperability or applicability) and compliance with the publication 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 do
13、es not suggest that compliance with the publication is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this publication may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the
14、 evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the publication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which ma
15、y be required to implement this publication. 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 2010 All rights reserved. No part of this publication may be re
16、produced, by any means whatsoever, without the prior written permission of ITU. G series Supplement 45 (05/2009) iii CONTENTS Page 1 Introduction 1 2 Power savings requirements . 1 2.1 Survey results . 1 2.2 EU Code of Conduct on Energy Consumption 2 2.3 Requirements profile summary 3 3 Classificati
17、on of power saving techniques . 4 3.1 Taxonomy. 4 3.2 Unified approach to ONU power saving signalling . 5 4 Power saving maintenance mechanisms. 5 4.1 Fast Sleep power saving technique. 5 4.2 Deep Sleep power saving technique. 7 4.3 Dozing power saving technique . 8 4.4 Power shedding 8 4.5 OMCI con
18、trol of the power saving techniques. 9 5 Signalling of ONU operations in a power saving mode. 9 5.1 Modified Dying Gasp PLOAM Signalling. 9 5.2 PLOAM-based signalling. 10 5.3 OMCI-based signalling 11 5.4 Extended power shedding. 12 5.5 Implicit power save mode signalling 13 5.6 Security aspect of po
19、wer save mode signalling 14 6 Comparative analysis 14 6.1 Methodology. 14 6.2 Power save mode signalling discussion . 14 6.3 Power save mode maintenance discussion. 15 7 Conclusions 19 Appendix I Power survey results 21 I.1 Power survey No.1 responses (LF08) 21 I.2 Power survey No. 2 responses 25 I.
20、3 Power survey No. 3 responses 33 G series Supplement 45 (05/2009) 1 Supplement 45 to ITU-T G-series Recommendations GPON power conservation 1 Introduction Power conservation and carbon footprint reduction has been embraced by ITU as a necessary goal. ITU-T has been exploring potential solutions to
21、improve power conservation through reduced power consumption and other techniques within optical access networks. These solutions can have an impact on improving equipment performance and service longevity in battery-powered operation, as well as on power conservation and CO2emissions in general. Wh
22、ile this Supplement focuses on GPON power savings, the results are expected to be applicable at least in part to GEPON as well as to NG-PON optical access. Throughout the years 2006 and 2007, FSAN and ITU-T have run three rounds of requirement-gathering power-saving surveys. The results of those sur
23、veys have revealed two foci of power-saving efforts: improving the power consumption characteristics of the optical access equipment with the goal to reduce its contribution into greenhouse gas emissions and improving the performance of the optical access equipment in mains outage situations. The su
24、rvey results have also demonstrated a considerable variability of the regulatory and operating environments where GPON is being or is planned to be deployed. Thus, the acceptable effect of any special power saving mode on perceived quality of service varies from “zero tolerance“ approach and full op
25、erator control to allow a certain degree of trade-offs and users freedom of choice. To satisfy the requirements that may vary by region, operator and application, multiple power conservation methods can be proposed and need to be documented and analysed. Such methods differ in achievable savings, as
26、 well as in the amount of required system architecture and system provisioning changes. One possible approach to classification of such methods is based on the depth of impact upon the existing GPON transmission convergence (GTC) layer as defined in ITU-T G.984.3 (2008). This Supplement is structure
27、d as follows. Clause 2 contains the condensed presentation of the FSAN/ITU-T GPON power savings survey results; the summary of principles and targets set by the EU Code of Conduct on Energy Consumption of Broadband Equipment, and the overview of the GPON power savings requirement profiles. Clauses 3
28、, 4 and 5 contain the specifications of the proposed power saving techniques partitioned by their relation to the GTC layer into the following groups: techniques involving introduction of the new PLOAM messages or new embedded OAM fields; techniques involving changing the semantics of existing PLOAM
29、 messages or embedded OAM fields; one-sided techniques that avoid changes to the GTC layer. Finally, clause 6 contains the comparative analysis of the proposed techniques with respect to the specified requirements and clause 7 presents the conclusions. 2 Power savings requirements 2.1 Survey results
30、 2.1.1 Survey No. 1 The first ITU-T power consumption survey, which was answered by four companies, was conducted in early 2007. 2 G series Supplement 45 (05/2009) Overall, while there was some scattering of data on many of the questions, there was not a sufficient response to say that any question
31、had a consensus answer. Despite this difficulty, it seemed clear from the responses that power saving is of lesser priority than service quality, availability and interface variety. This led to the conclusion that power saving features should be carefully designed such that they would not sacrifice
32、these other priorities. 2.1.2 Survey No. 2 Survey No. 2 was distributed in September 2007. It was addressed specifically to the operator community. Four operators responded to the survey by the meeting deadline and one more provided the responses post factum. All would like an energy saving mode to
33、economize on battery power for back-up of essential services such as telephony (two would like it to be same as the low power mode in the EU Code of Conduct on Energy Consumption of Broadband Equipment). The responders showed strong interest in a digital telephony interface of 300 kbit/s or less. Al
34、l would like an energy saving mode; however, most required the trigger to be mains failure, rather than unused ports or lack of traffic. Some of the requirements were formulated: Same port shutdown sequence was agreed as suggested in the questionnaire. Programmable data rates (but no consensus on sp
35、ecific values). Less than 5-s recovery time to full power mode. While patchy support was shown for the power save mode when traffic was light or ports remained unused, the decision was made for the vendors to focus on power saving for power backup under supply failure. 2.1.3 Survey No. 3 Survey No.
36、3 was formulated after the November 2007 meeting with the aim of clarifying the service requirements for the power saving performance under mains power outage. Four operators provided the responses, confirming the importance of the power savings theme; however, no consistent set of service requireme
37、nts and acceptable trade-offs appeared as a result of the survey. 2.2 EU Code of Conduct on Energy Consumption Code of Conduct on Energy Consumption of Broadband Communication Equipment (referred herein as BBCoC) is a document issued by the European Commission that sets out the basic principles to b
38、e followed by all parties involved in broadband equipment, operating in the European Community, in respect of energy-efficient equipment. All service providers, network operators, equipment and component manufacturers are invited to sign this document on a voluntary basis. There have been three publ
39、ished versions of BBCoC: Version 1: Ispra, 19 July 2006; Version 2: Ispra, 17 July 2007; Version 3; Ispra, 18 November 2008. The current version is available at: http:/re.jrc.ec.europa.eu/energyefficiency/html/standby_initiative_broadband%20communication.htm The BBCoC defines the general principles
40、of power savings in broadband equipment, provides the functional definitions of operation states, and sets the target power levels along with the time schedule for compliance. It classifies optical line termination (OLT) as network equipment and the optical network termination (ONT) as customer prem
41、ises equipment of home gateway type. G series Supplement 45 (05/2009) 3 Consider as an example two typical ONT1configuration styles as defined in the following table. Table 1 Typical ONT configuration styles Interfaces Typical ONT Configurations GPON GE POTS MoCA Style 1 1 1 2 1 Style 2 1 4 2 0 The
42、BBCoC would impose the following power level requirements on these ONTs. Table 2 Target power levels for a style l ONT Tier 2009/2010 1.1.2009-31.12.2010 Tier 2011 1.1.2011-31.12.2011 Function Low power state (W) On state (W) Low power state (W) On state (W) General functions + GPON interface 5.0 9.
43、7 4.0 7.7 1 gigabit Ethernet port 0.3 1.7 0.3 1.3 Dual SLIC (FXS) (Note) 0.8 3.0 0.5 3.0 MoCA 0.4 4.0 2.0 2.5 Total equipment 10.1 18.4 6.8 14.5 NOTE Assuming one interface is totally off in the low power state. Table 3 Target power levels for a style 2 ONT Tier 2009/2010 1.1.2009-31.12.2010 Tier 20
44、11 1.1.2011-31.12.2011 Function Low power state (W) On state (W) Low power state (W) On state (W) General functions + GPON interface 5.0 9.7 4.0 7.7 4 port gigabit Ethernet switch 1.5 4.5 1.2 3.7 Dual SLIC (FXS) (Note) 0.8 3.0 0.5 3.0 Total equipment 7.3 17.2 5.7 14.4 NOTE Assuming one interface is
45、totally off in the low power state. 2.3 Requirements profile summary As the surveys indicate, the ONU1power savings requirements can be associated with one of the two dominating underlying objectives. On one hand, the effort is driven by the emergency services support under the AC mains power failur
46、e and is targeted at the prolongation of the battery operation time. On the other hand, the requirements focus on conserving power in regular (mains _ 1The usage of the terms ONT and ONU throughout this Supplement follows the convention of ITU-T G.984.3 (2008). In addition, in the context of a parti
47、cular reference discussion, preference is given to the term used within the specific reference. 4 G series Supplement 45 (05/2009) powered) operations and minimizing the carbon dioxide emissions generated by information and communications technologies (ICTs). The key difference between the two objec
48、tives and the two associated requirements profiles is the degree of compromise on the scope and quality of service that is considered acceptable. There are also varying approaches to the degree of freedom delegated to the end user in asserting his or her preferences with regard to GPON functionality
49、 under power outage. Individual operators may focus on only one or both of the two objectives in compliance, respectively, with the telecommunications regulations for the specific jurisdiction or the BBCoC. It has been observed that in many cases the existing regulations tend to suit the conventional copper plant (which provides power from the CO), and are yet to address the specifics of fibre access. In the case of the wholesale open access model, the authority to establish the service requirements, prior
