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Terminology for Energy Efficiency Network Management
draft-bclp-green-terminology-00

Document Type Active Internet-Draft (individual)
Authors Peter Chunchi Liu , Mohamed Boucadair , Qin Wu , Luis M. Contreras , Marisol Palmero
Last updated 2024-10-10
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draft-bclp-green-terminology-00
GREEN Working Group                                               C. Liu
Internet-Draft                                                    Huawei
Intended status: Informational                              M. Boucadair
Expires: 13 April 2025                                            Orange
                                                                   Q. Wu
                                                                  Huawei
                                                         L. M. Contreras
                                                              Telefonica
                                                              M. Palmero
                                                                   Cisco
                                                         10 October 2024

          Terminology for Energy Efficiency Network Management
                    draft-bclp-green-terminology-00

Abstract

   Energy-efficient network management is primary meant to enhance
   conventional network management with energy-related management
   capabilities to optimize the overall energy consumption at the level
   of a network.  To that aim, specific features and capabilities are
   required to control (and thus optimize) the energy use of involved
   network element and their components.

   This document is defines a set of key terms used within the IETF when
   discussing energy efficiency in network management.  Such reference
   document helps framing discussion and agreeing upon a set of main
   concepts in this area.

Discussion Venues

   This note is to be removed before publishing as an RFC.

   Discussion of this document takes place on the Getting Ready for
   Energy-Efficient Networking Working Group mailing list
   (green@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/green/.

   Source for this draft and an issue tracker can be found at
   https://github.com/billwuqin/draft-bclp-green-terminology.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on 13 April 2025.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   Please review these documents carefully, as they describe your rights
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Abbreviations . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Sample Energy Efficiency Metrics and Measurement Methods  . .   5
     4.1.  Metrics for DSLAM, MSAN, GPON, and GEPON Equipment  . . .   5
     4.2.  Metric for Wireless Access Technologies . . . . . . . . .   6
     4.3.  Metrics for Routers and Ethernet Switches . . . . . . . .   6
     4.4.  Metrics for Small Network Devices . . . . . . . . . . . .   7
     4.5.  Metric for Power Equipment  . . . . . . . . . . . . . . .   7
     4.6.  Metric for Cooling Equipment  . . . . . . . . . . . . . .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   6.  Informative References  . . . . . . . . . . . . . . . . . . .   8
   Appendix A.  Standards Bodies and Standards . . . . . . . . . . .   9
     A.1.  ITU-T SG5 . . . . . . . . . . . . . . . . . . . . . . . .   9
     A.2.  ETSI TCEE . . . . . . . . . . . . . . . . . . . . . . . .  10
     A.3.  3GPP SA5  . . . . . . . . . . . . . . . . . . . . . . . .  10
   Appendix B.  Acknowledgments  . . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

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1.  Introduction

   With rising energy costs and increasing awareness of the
   environmental impact of running networks, servers, and various
   equipment, Energy Efficiency is considered by operators as a critical
   component to be integrated in the overall Network Management systems.
   Such integration is ambitioned to feed strategies for committing
   environmental objectives but also mastering related operational cost.
   Energy Efficiency management is thus complementing conventional
   network management.

   Section 3 defines a set of terms used within the IETF when discussing
   Energy-efficiency networks.  The purpose is to (1) ensure consistent
   use of a set of terms in this area, (2) help with the
   characterization of Energy Efficiency (and relevant aspects), (3)
   assist in the development of the YANG data models at the different
   levels in the IETF, and (4) bring clarity to the Energy Efficiency
   related discussions between different groups within IETF, in
   particular.

   This document does not intend to define a comprehensive list of
   energy-related terms.  Only key terms are defined.  Some of these
   terms are extracted from existing IETF documents and beyond.

   Also, Section 4 provides an inventory of currently used metrics to
   assess/compute energy-related consumption, efficiency ratio, etc.

   Appendix A provides a list of SDOs where relevant energy efficiency
   effort is ongoing.

2.  Abbreviations

   The following abbreviations are used in the document:

   CLEE:  Component Level Energy Efficiency

   DLEE:  Device Level Energy Efficiency

   DSLAM:  Digital Subscriber Line Access Multiplexer

   EER  Energy Efficiency Ratio

   GEPON:  Gigabit Ethernet Passive Optical Network

   GPON:  Gigabit-capable Passive Optical Network

   MSAN:  Multiservice Access Node

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   NLEE:  Network Level Energy Efficiency

   PUE:  Power Usage Effectiveness

3.  Definitions

   Terms are listed so that terms that are needed to understand other
   terms are listed first.

   Energy:  Is generally a reference to electrical energy and is
      measured in kilowatt-hours (kWh) ([RFC7326]).

   Power:  Refers the time rate at which energy is emitted, transferred,
      or received; power is usually expressed in watts (joules per
      second) ([RFC7326]).

   Energy Management:  Is a set of functions for measuring, modeling,
      planning, and optimizing networks to ensure that the network and
      network-attached devices use energy efficiently and appropriately
      for the nature of the application and the cost constraints of the
      organization ([RFC7326]).

   Energy Monitoring:  Is a part of Energy Management that deals with
      collecting or reading information from devices to aid in Energy
      Management ([RFC7326]).

   Energy Control:  Is a part of Energy Management that deals with
      directing influence over devices ([RFC7326]).

      This control can span a network or a subset of it.

   Energy Efficiency Network Management:  Refers to the ability to
      control the use of available energy in an optimized manner (e.g.,
      in a resource conserved manner and at low cost) in a network.

   Energy Efficiency Metric:  Refers to a metric that is used for the
      evaluation and assessment of energy consumption of a network,
      device, or component.  One or more metrics can be defined.  These
      metrics are also used for network performance purposes to
      characterize the effectiveness of an Energy Efficiency management
      strategy.

   Energy Efficiency/Energy Efficiency Ratio (EER):  The energy
      efficiency is expressed as the ratio between the useful output and
      input of an energy conversion process of a network, device, or
      component.

      For instance, in relation with a networking device, it can be

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      stated as the ratio of total throughput (e.g., of a network
      element capacity) to the total power consumed (bits/Joule).

      This ratio (i.e., Energy Efficiency Ratio, EER) is the throughput
      forwarded by 1 watt (e.g., [I-D.cprjgf-bmwg-powerbench]).

      A higher EER indicates a better energy efficiency.

   Power Usage Effectiveness (PUE):  Refer to the metric used to measure
      the energy efficiency of an infrastructure.

      This metric is calculated as the ratio between the total energy
      consumed by an infrastructure and the energy needed for a network
      element/component.

   Network Level Energy Efficiency (NLEE):  Denotes the Energy
      Efficiency of an entire network or a subset part of it (e.g.,
      access network).

   Device Level Energy Efficiency (DLEE):  Denotes the Energy Efficiency
      of a network element.  It can be used, e.g., to compare network
      elements providing the same functionality or a target to optiize
      the configuration of a a network element.

   Component Level Energy Efficiency (CLEE):  Denotes the Energy
      Efficiency of a component of a network element.  It can be used in
      the design, development, and manufacturing of energy efficient a
      network elements.

      Is useful to evaluate the energy efficiency performance of
      individual components of a network element.

      Measuring and understanding the energy efficiency or energy
      consumption of each component within a network element may be used
      to identify key components in a system with regard to energy
      saving.

4.  Sample Energy Efficiency Metrics and Measurement Methods

   This section lists some metrics that are adopted by other SDOs.

      DISCUSS: Should we maintian this section?

4.1.  Metrics for DSLAM, MSAN, GPON, and GEPON Equipment

   Equipment with line cards working at different profiles/states are
   characterized with different metric values for each specific profile/
   state.

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                         Pport = Peq/Nports[W/port]

   Where 'Peq' is the power (in watts) of a fully equipped wireline
   network equipment with all its line cards working in a specific
   profile/state.  The formula is defined in [L.1310].

4.2.  Metric for Wireless Access Technologies

   The energy efficiency metric at Radio Frequency (RF) unit level is as
   follows:

                        EErfu = Eoutput/Erfu

   Where:

   *  'Eoutput' is daily RF output energy consumption [Wh] under
      different load.

   *  'Erfu' is daily RF units energy consumption [Wh] under different
      load.

   The formula is defined in [L.1310].

4.3.  Metrics for Routers and Ethernet Switches

   The metric for routers and Ethernet switches is as follows:

                       EER = Ti/Pw [Mbit/s/W]

   Where 'Ti' is weighted throughput, 'Pw' is weighted power (energy
   consumption rate).  The formula is defined in [L.1310].

                       Ti = a*Tu1 + b*Tu2 + c*Tu3
                       Pw = a*Pu1 + b*Pu2 + c*Pu3

   Where:

   *  'a'/'b'/'c' are the relative weight at different usage percentage
      with a+b+c=1.

   *  'Pu1'/'Pu2'/'Pu3' are the power at different usage percentage.

   *  'Tu1'/'Tu2'/'Tu3' are the throughput at different usage
      percentage.

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4.4.  Metrics for Small Network Devices

   A metric for small networking devices intended for home/domestic or
   small office use is as follows:

                      EER = Ti/Pw [Mbit/s/W]

   Where Ti is weighted throughput between wide area network (WAN) and
   local area network (LAN) ports in the ingress direction, Pw is
   weighted power (energy consumption rate), the formula is defined in
   [L.1310].

                     Ti = 0.35T_idle+0.5*T_lowpower+0.15*T_maximum
                     Pw = 0.35P_idle+0.5P_lowpower+0.15P_maximum

   where:

   *  (0.35,0.5,0.15) is the relative weight at different usage
      percentage.

   *  'P_idle'/'P_lowpower'/'P_maximum' is the power at different usage
      percentage.

   *  'T_idle'/'T_lowpower'/'T_maximum' is the throughput at different
      usage percentage.

4.5.  Metric for Power Equipment

                              δ = Po/Pi

   Where:

   *  'Po' is output power.

   *  'Pi' is input power.

   This energy efficiency value is measured or calculated from the
   testing data over a given time period.  The formula is defined in
   [L.1320].

4.6.  Metric for Cooling Equipment

                             η = Qt/Pi

   Where:

   *  'η' is the energy efficiency of the air conditioner.

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   *  'Pi' is the input power.

   *  'Qt' is the sum of the sensible cooling capacity and the latent
      cooling capacity.

   The formula is defined in [L.1320].

5.  Security Considerations

   Security is not discussed in this document.

6.  Informative References

   [ETSI-ES-203-136]
              "Environmental Engineering (EE); Measurement methods for
              energy efficiency of router and switch equipment", 2017,
              <https://www.etsi.org/deliver/
              etsi_es/203100_203199/203136/01.02.00_50/
              es_203136v010200m.pdf>.

   [I-D.cprjgf-bmwg-powerbench]
              Pignataro, C., Jacob, R., Fioccola, G., and Q. Wu,
              "Characterization and Benchmarking Methodology for Power
              in Networking Devices", Work in Progress, Internet-Draft,
              draft-cprjgf-bmwg-powerbench-02, 6 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-cprjgf-bmwg-
              powerbench-02>.

   [L.1310]   "Energy efficiency metrics and measurement methods for
              telecommunication equipment", 2024,
              <https://www.itu.int/rec/T-REC-L.1310-202409-P>.

   [L.1315]   "Standardization terms and trends in energy efficiency",
              2017, <https://www.itu.int/rec/T-REC-L.1315-201705-I>.

   [L.1316]   "Energy efficiency framework", 2019,
              <https://www.itu.int/rec/T-REC-L.1316-201911-I>.

   [L.1320]   "Energy efficiency metrics and measurement for power and
              cooling equipment for telecommunications and data
              centres", 2014,
              <https://www.itu.int/rec/T-REC-L.1320-201403-I>.

   [L.1331]   "Assessment of mobile network energy efficiency", 2020,
              <https://www.itu.int/rec/T-REC-L.1331-202009-S>.

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   [L.1333]   "Carbon data intensity for network energy performance
              monitoring", 2022,
              <https://handle.itu.int/11.1002/1000/15028>.

   [L.1410]   "Methodology for environmental life cycle assessments of
              information and communication technology goods, networks
              and services", 2014,
              <https://www.itu.int/rec/T-REC-L.1410-201412-I>.

   [RFC7326]  Parello, J., Claise, B., Schoening, B., and J. Quittek,
              "Energy Management Framework", RFC 7326,
              DOI 10.17487/RFC7326, September 2014,
              <https://www.rfc-editor.org/rfc/rfc7326>.

   [TS28.554] "Management and orchestration; 5G end to end Key
              Performance Indicators (KPI)", 2024,
              <https://www.3gpp.org/ftp/Specs/
              archive/28_series/28.554/28554-i70.zip>.

Appendix A.  Standards Bodies and Standards

   This appendix provides a list of SDOs where relevant energy
   efficiency effort is ongoing.  This appendix does not aim to be
   comprehensive.  The appendix may be removed in future versions of the
   document.

A.1.  ITU-T SG5

   ITU-T Study Group 5 (SG5) has already worked on developing standards
   on energy efficiency.  ITU-T SG5 has many standards in the
   environment efficiency field.  These standards include [L.1310],
   [L.1315], [L.1316], and [L.1320] covering energy efficiency
   terminology, framework, metrics, and measurement methods.

   ITU-T SG5 is also responsible for other standards that might be of
   interest to protocol developers and network operators.  For example:

   *  [L.1331] specifies assessment of mobile network energy efficiency.

   *  [L.1333] specifies the correlation between the carbon intensity
      indicator and energy efficiency metric.  The carbon KPI defined in
      [L.1333] refers to the energy efficiency metric defined in ITU-T
      L.1331.

   *  [L.1410] focuses on the assessment of the environmental impact of
      information and communication technology (ICT) goods, networks and
      services.  It provides specific guidance on energy and greenhouse
      gas (GHG) impacts.

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A.2.  ETSI TCEE

   ETSI Technical Committee (TC) Environment Engineering (EE) is
   collaborating with ITU-T SG5 to develop technically aligned standards
   on energy efficiency and environment aspect.  These standards include
   energy efficiency, power feeding solution, circular economy and
   network efficiency KPI and eco-design requirement for ICT, with the
   aim to build an international eco-environmental standardization.

   [ETSI-ES-203-136] defines the energy consumption metrics and
   measurement methods for router and Ethernet switch equipment.  It
   specifies a methodology and the test conditions to measure the power
   consumption of router and switch equipment and is also applicable to
   Core, edge, and access routers.

A.3.  3GPP SA5

   3GPP SA5 has, in Release 17, extended its scope from RAN only to the
   whole 5G System (5GS) and worked on Energy Efficiency (EE) and Energy
   Saving (ES) of mobile networks.  EE Key Performance Indicators (KPI)
   have been defined for the 5G Core network and Network Slices.

   The 3GPP Energy Efficiency in the RAN is defined by the performance
   divided by the Energy Consumption (EC), where the definition of the
   performance depends on the type of network entity it applies to.
   From this, SA5 work aimed at defining the best metrics for each of
   them, and their measurement method.

   In Rel-18, WG SA5 works with ETSI NFV to explore more accurate
   virtual CPU usage measurements from ETSI NFV MANO, Introduce
   additional metrics when estimating the Energy Consumption of Virtual
   Machines, e.g., their virtual disk or link usage.  In addition new
   use cases for Energy Saving, applied to NG-RAN, 5GC, and Network
   Slicing, AI/ML assisted energy saving scenarios are also being
   investigated.

   Specifically, [TS28.554] defines a number of energy efficiency KPIs,
   including a generic Network Slice Energy Efficiency KPI, defined as
   the ratio between the performance of the network slice and its energy
   consumption.

Appendix B.  Acknowledgments

   TODO acknowledge.

Authors' Addresses

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   Chunchi Liu
   Huawei
   Email: liuchunchi@huawei.com

   Mohamed Boucadair
   Orange
   Email: mohamed.boucadair@orange.com

   Qin Wu
   Huawei
   Email: bill.wu@huawei.com

   Luis M. Contreras
   Telefonica
   Email: luismiguel.contrerasmurillo@telefonica.com

   Marisol Palmero
   Cisco
   Email: mpalmero@cisco.com

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