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Internet Engineering Task Force (IETF) B. Schoening Request for Comments: 7603 Independent Consultant Category: Standards Track M. Chandramouli ISSN: 2070-1721 Cisco Systems, Inc.

                                                            B. Nordman
                                        Lawrence Berkeley National Lab
                                                           August 2015
          Energy Management (EMAN) Applicability Statement

Abstract

 The objective of Energy Management (EMAN) is to provide an energy
 management framework for networked devices.  This document presents
 the applicability of the EMAN information model in a variety of
 scenarios with cases and target devices.  These use cases are useful
 for identifying requirements for the framework and MIBs.  Further, we
 describe the relationship of the EMAN framework to other relevant
 energy monitoring standards and architectures.

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc7603.

Schoening, et al. Standards Track [Page 1] RFC 7603 EMAN Applicability Statement August 2015

Copyright Notice

 Copyright (c) 2015 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
 Provisions Relating to IETF Documents
 (http://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Table of Contents

 1. Introduction ................................................. 3
   1.1. Energy Management Overview ............................... 4
   1.2. EMAN Document Overview ................................... 4
   1.3. Energy Measurement ....................................... 5
   1.4. Energy Management ........................................ 5
   1.5. EMAN Framework Application ............................... 6
 2. Scenarios and Target Devices ................................. 6
   2.1. Network Infrastructure Energy Objects .................... 6
   2.2. Devices Powered and Connected by a Network Device ........ 7
   2.3. Devices Connected to a Network ........................... 8
   2.4. Power Meters ............................................. 9
   2.5. Mid-level Managers ...................................... 10
   2.6. Non-residential Building System Gateways ................ 10
   2.7. Home Energy Gateways .................................... 11
   2.8. Data Center Devices ..................................... 12
   2.9. Energy Storage Devices .................................. 13
   2.10. Industrial Automation Networks ......................... 14
   2.11. Printers ............................................... 14
   2.12. Demand Response ........................................ 15
 3. Use Case Patterns ........................................... 16
   3.1. Metering ................................................ 16
   3.2. Metering and Control .................................... 16
   3.3. Power Supply, Metering and Control ...................... 16
   3.4. Multiple Power Sources .................................. 16
 4. Relationship of EMAN to Other Standards ..................... 17
   4.1. Data Model and Reporting ................................ 17
         4.1.1. IEC - CIM........................................ 17
         4.1.2. DMTF............................................. 17
         4.1.3. ODVA............................................. 19
         4.1.4. Ecma SDC......................................... 19
         4.1.5. PWG.............................................. 19

Schoening, et al. Standards Track [Page 2] RFC 7603 EMAN Applicability Statement August 2015

         4.1.6. ASHRAE........................................... 20
         4.1.7. ANSI/CEA......................................... 21
         4.1.8. ZigBee........................................... 21
   4.2. Measurement ............................................. 22
         4.2.1. ANSI C12......................................... 22
         4.2.2. IEC 62301........................................ 22
   4.3. Other ................................................... 22
         4.3.1. ISO.............................................. 22
         4.3.2. Energy Star...................................... 23
         4.3.3. Smart Grid....................................... 23
 5. Limitations ................................................. 24
 6. Security Considerations ..................................... 24
 7. References .................................................. 25
   7.1. Normative References .................................... 25
   7.2. Informative References .................................. 25
 Acknowledgements ............................................... 27
 Authors' Addresses ............................................. 28

1. Introduction

 The focus of the Energy Management (EMAN) framework is energy
 monitoring and management of energy objects [RFC7326].  The scope of
 devices considered are network equipment and their components, and
 devices connected directly or indirectly to the network.  The EMAN
 framework enables monitoring of heterogeneous devices to report their
 energy consumption and, if permissible, control.  There are multiple
 scenarios where this is desirable, particularly considering the
 increased importance of limiting consumption of finite energy
 resources and reducing operational expenses.
 The EMAN framework [RFC7326] describes how energy information can be
 retrieved from IP-enabled devices using Simple Network Management
 Protocol (SNMP), specifically, Management Information Base (MIB)
 modules for SNMP.
 This document describes typical applications of the EMAN framework as
 well as its opportunities and limitations.  It also reviews other
 standards that are similar in part to EMAN but address different
 domains, describing how those other standards relate to the EMAN
 framework.
 The rest of the document is organized as follows.  Section 2 contains
 a list of use cases or network scenarios that EMAN addresses.
 Section 3 contains an abstraction of the use case scenarios to
 distinct patterns.  Section 4 deals with other standards related and
 applicable to EMAN.

Schoening, et al. Standards Track [Page 3] RFC 7603 EMAN Applicability Statement August 2015

1.1. Energy Management Overview

 EMAN addresses the electrical energy consumed by devices connected to
 a network.  A first step to increase the energy efficiency in
 networks and the devices attached to the network is to enable energy
 objects to report their energy usage over time.  The EMAN framework
 addresses this problem with an information model for electrical
 equipment: energy object identification, energy object context, power
 measurement, and power characteristics.
 The EMAN framework defines SNMP MIB modules based on the information
 model.  By implementing these SNMP MIB modules, an energy object can
 report its energy consumption according to the information model.
 Based on the information model, the MIB documents specify SNMP MIB
 modules, but it is equally possible to use other mechanisms such as
 YANG module, Network Conference Protocol (NETCONF), etc.
 In that context, it is important to distinguish energy objects that
 can only report their own energy usage from devices that can also
 collect and aggregate energy usage of other energy objects.

1.2. EMAN Document Overview

 The EMAN work consists of the following Standard Track and
 Informational documents in the area of energy management.
    Applicability Statement (this document)
    Requirements [RFC6988]: This document presents requirements of
       energy management and the scope of the devices considered.
    Framework [RFC7326]: This document defines a framework for
       providing energy management for devices within or connected to
       communication networks and lists the definitions for the common
       terms used in these documents.
    Energy Object Context MIB [RFC7461]: This document defines a MIB
       module that characterizes a device's identity, context, and
       relationships to other entities.
    Monitoring and Control MIB [RFC7460]: This document defines a MIB
       module for monitoring the power and energy consumption of a
       device.
       The MIB module contains an optional module for metrics
       associated with power characteristics.

Schoening, et al. Standards Track [Page 4] RFC 7603 EMAN Applicability Statement August 2015

    Battery MIB [RFC7577]: This document defines a MIB module for
       monitoring characteristics of an internal battery.

1.3. Energy Measurement

 It is increasingly common for today's smart devices to measure and
 report their own energy consumption.  Intelligent power strips and
 some Power over Ethernet (PoE) switches can meter consumption of
 connected devices.  However, when managed and reported through
 proprietary means, this information is difficult to view at the
 enterprise level.
 The primary goal of the EMAN information model is to enable reporting
 and management within a standard framework that is applicable to a
 wide variety of end devices, meters, and proxies.  This enables a
 management system to know who's consuming what, when, and how by
 leveraging existing networks across various equipment in a unified
 and consistent manner.
 Because energy objects may both consume energy and provide energy to
 other devices, there are three types of energy measurement: energy
 input to a device, energy supplied to other devices, and net
 (resultant) energy consumed (the difference between energy input and
 supplied).

1.4. Energy Management

 The EMAN framework provides mechanisms for energy control in addition
 to passive monitoring.  There are many cases where active energy
 control of devices is desirable, for example, during low device
 utilization or peak electrical price periods.
 Energy control can be as simple as controlling on/off states.  In
 many cases, however, energy control requires understanding the energy
 object context.  For instance, during non-business hours in a
 commercial building, some phones must remain available in case of
 emergency, and office cooling is not usually turned off completely,
 but the comfort level is reduced.
 Energy object control therefore requires flexibility and support for
 different policies and mechanisms: from centralized management by an
 energy management system to autonomous control by individual devices
 and alignment with dynamic demand-response mechanisms.
 The power states specified in the EMAN framework can be used in
 demand-response scenarios.  In response to time-of-day fluctuation of
 energy costs or grid power shortages, network devices can respond and
 reduce their energy consumption.

Schoening, et al. Standards Track [Page 5] RFC 7603 EMAN Applicability Statement August 2015

1.5. EMAN Framework Application

 A Network Management System (NMS) is an entity that requests
 information from compatible devices, typically using the SNMP
 protocol. An NMS may implement many network management functions,
 such as security or identity management.  An NMS that deals
 exclusively with energy is called an Energy Management System (EnMS).
 It may be limited to monitoring energy use, or it may also implement
 control functions.  An EnMS collects energy information for devices
 in the network.
 Energy management can be implemented by extending existing SNMP
 support with EMAN-specific MIBs.  SNMP provides an industry-proven
 and well-known mechanism to discover, secure, measure, and control
 SNMP-enabled end devices.  The EMAN framework provides an information
 and data model to unify access to a large range of devices.

2. Scenarios and Target Devices

 This section presents energy management scenarios that the EMAN
 framework should solve.  Each scenario lists target devices for which
 the energy management framework can be applied, how the reported-on
 devices are powered, and how the reporting or control is
 accomplished.  While there is some overlap between some of the use
 cases, the use cases illustrate network scenarios that the EMAN
 framework supports.

2.1. Network Infrastructure Energy Objects

 This scenario covers the key use case of network devices and their
 components.  For a device aware of one or more components, our
 information model supports monitoring and control at the component
 level.  Typically, the chassis draws power from one or more sources
 and feeds its internal components.  It is highly desirable to have
 monitoring available for individual components, such as line cards,
 processors, disk drives, and peripherals such as USB devices.
 As an illustrative example, consider a switch with the following
 grouping of subentities for which energy management could be useful.
    o  Physical view: chassis (or stack), line cards, and service
       modules of the switch.
    o  Component view: CPU, Application-Specific Integrated Circuits
       (ASICs), fans, power supply, ports (single port and port
       groups), storage, and memory.

Schoening, et al. Standards Track [Page 6] RFC 7603 EMAN Applicability Statement August 2015

 The ENTITY-MIB [RFC6933] provides a containment model for uniquely
 identifying the physical subcomponents of network devices.  The
 containment information identifies whether one Energy Object belongs
 to another Energy Object (e.g., a line-card Energy Object contained
 in a chassis Energy Object).  The mapping table,
 entPhysicalContainsTable, has an index, entPhysicalChildIndex, and
 the table, entPhysicalTable, has a MIB object,
 entPhysicalContainedIn, that points to the containing entity.
 The essential properties of this use case are:
    o  Target devices: network devices such as routers and switches,
       as well as their components.
    o  How powered: typically by a Power Distribution Unit (PDU) on a
       rack or from a wall outlet.  The components of a device are
       powered by the device chassis.
    o  Reporting: Direct power measurement can be performed at a
       device level.  Components can report their power consumption
       directly, or the chassis/device can report on behalf of some
       components.

2.2. Devices Powered and Connected by a Network Device

 This scenario covers Power Sourcing Equipment (PSE) devices.  A PSE
 device (e.g., a PoE switch) provides power to a Powered Device (PD)
 (e.g., a desktop phone) over a medium such as USB or Ethernet
 [RFC3621].  For each port, the PSE can control the power supply
 (switching it on and off) and usually meter actual power provided.
 PDs obtain network connectivity as well as power over a single
 connection so the PSE can determine which device is associated with
 each port.
 PoE ports on a switch are commonly connected to devices such as IP
 phones, wireless access points, and IP cameras.  The switch needs
 power for its internal use and to supply power to PoE ports.
 Monitoring the power consumption of the switch (supplying device) and
 the power consumption of the PoE endpoints (consuming devices) is a
 simple use case of this scenario.
 This scenario illustrates the relationships between entities.  The
 PoE IP phone is powered by the switch.  If there are many IP phones
 connected to the same switch, the power consumption of all the IP
 phones can be aggregated by the switch.

Schoening, et al. Standards Track [Page 7] RFC 7603 EMAN Applicability Statement August 2015

 The essential properties of this use case are:
    Target devices: Power over Ethernet devices such as IP phones,
       wireless access points, and IP cameras.
    How powered: PoE devices are connected to the switch port that
       supplies power to those devices.
    Reporting: PoE device power consumption is measured and reported
       by the switch (PSE) that supplies power.  In addition, some
       edge devices can support the EMAN framework.
 This use case can be divided into two subcases:
    a) The endpoint device supports the EMAN framework, in which case
       this device is an EMAN Energy Object by itself with its own
       Universally Unique Identifier (UUID).  The device is
       responsible for its own power reporting and control.  See the
       related scenario "Devices Connected to a Network" below.
    b) The endpoint device does not have EMAN capabilities, and the
       power measurement may not be able to be performed independently
       and is therefore only performed by the supplying device.  This
       scenario is similar to the "Mid-level Manager" below.
 In subcase (a), note that two power usage reporting mechanisms for
 the same device are available: one performed by the PD itself and one
 performed by the PSE.  Device-specific implementations will dictate
 which one to use.

2.3. Devices Connected to a Network

 This use case covers the metering relationship between an energy
 object and the parent energy object to which it is connected, while
 receiving power from a different source.
 An example is a PC that has a network connection to a switch but
 draws power from a wall outlet.  In this case, the PC can report
 power usage by itself, ideally through the EMAN framework.
 The wall outlet to which the PC is plugged in can be unmetered or
 metered, for example, by a Smart PDU.
    a) If metered, the PC has a powered-by relationship to the Smart
       PDU, and the Smart PDU acts as a "mid-level manager".

Schoening, et al. Standards Track [Page 8] RFC 7603 EMAN Applicability Statement August 2015

    b) If unmetered, or operating on batteries, the PC will report its
       own energy usage as any other Energy Object to the switch, and
       the switch may possibly provide aggregation.
 These two cases are not mutually exclusive.
 In terms of relationships between entities, the PC has a powered-by
 relationship to the PDU, and if the power consumption of the PC is
 metered by the PDU, then there is a metered-by relation between the
 PC and the PDU.
 The essential properties of this use case are:
    o  Target devices: energy objects that have a network connection
       but receive power supply from another source.
    o  How powered: endpoint devices (e.g., PCs) receive power supply
       from the wall outlet (unmetered), a PDU (metered), or can be
       powered autonomously (batteries).
    o  Reporting: The power consumption can be reported via the EMAN
       framework
       -  by the device directly,
       -  by the switch with information provided to it by the device,
          or
       -  by the PDU from which the device obtains its power.

2.4. Power Meters

 Some electrical devices are not equipped with instrumentation to
 measure their own power and accumulated energy consumption.  External
 meters can be used to measure the power consumption of such
 electrical devices as well as collections of devices.
 Three types of external metering are relevant to EMAN: PDUs,
 standalone meters, and utility meters.  External meters can measure
 consumption of a single device or a set of devices.
 Power Distribution Units (PDUs) can have built-in meters for each
 socket and can measure the power supplied to each device in an
 equipment rack.  PDUs typically have remote management capabilities
 that can report and possibly control the power supply of each outlet.
 Standalone meters can be placed anywhere in a power distribution tree
 and may measure all or part of the total.  Utility meters monitor and
 report accumulated power consumption of the entire building.  There
 can be submeters to measure the power consumption of a portion of the
 building.

Schoening, et al. Standards Track [Page 9] RFC 7603 EMAN Applicability Statement August 2015

 The essential properties of this use case are:
    o  Target devices: PDUs and meters.
    o  How powered: from traditional mains power but supplied through
       a PDU or meter (where "mains power" is the standard AC power
       drawn from the wall outlet).
    o  Reporting: PDUs report power consumption of downstream devices,
       usually a single device per outlet.  Meters may report for one
       or more devices and may require knowledge of the topology to
       associate meters with metered devices.
 Meters have metered-by relationships with devices and may have
 aggregation relationships between the meters and the devices for
 which power consumption is accumulated and reported by the meter.

2.5. Mid-level Managers

 This use case covers aggregation of energy management data at "mid-
 level managers" that can provide energy management functions for
 themselves and associated devices.
 A switch can provide energy management functions for all devices
 connected to its ports whether or not these devices are powered by
 the switch or whether the switch provides immediate network
 connectivity to the devices.  Such a switch is a mid-level manager,
 offering aggregation of power consumption data for other devices.
 Devices report their EMAN data to the switch and the switch
 aggregates the data for further reporting.
 The essential properties of this use case:
    o  Target devices: devices that can perform aggregation; commonly
       a switch or a proxy.
    o  How powered: mid-level managers are commonly powered by a PDU
       or from a wall outlet but can be powered by any method.
    o  Reporting: The mid-level manager aggregates the energy data and
       reports that data to an EnMS or higher mid-level manager.

2.6. Non-residential Building System Gateways

 This use case describes energy management of non-residential
 buildings.  Building Management Systems (BMS) have been in place for
 many years using legacy protocols not based on IP.  In these
 buildings, a gateway can provide a proxy function between IP networks

Schoening, et al. Standards Track [Page 10] RFC 7603 EMAN Applicability Statement August 2015

 and legacy building automation protocols.  The gateway provides an
 interface between the EMAN framework and relevant building management
 protocols.
 Due to the potential energy savings, energy management of buildings
 has received significant attention.  There are gateway network
 elements to manage the multiple components of a building energy
 management system such as Heating, Ventilation, and Air Conditioning
 (HVAC), lighting, electrical, fire and emergency systems, elevators,
 etc.  The gateway device uses legacy building protocols to
 communicate with those devices, collects their energy usage, and
 reports the results.
 The gateway performs protocol conversion and communicates via
 RS-232/RS-485 interfaces, Ethernet interfaces, and protocols specific
 to building management such as BACnet (a protocol for building
 automation and control networks) [BACnet], Modbus [MODBUS], or ZigBee
 [ZIGBEE].
 The essential properties of this use case are:
    o  Target devices: building energy management devices -- HVAC
       systems, lighting, electrical, and fire and emergency systems.
    o  How powered: any method.
    o  Reporting: The gateway collects energy consumption of non-IP
       systems and communicates the data via the EMAN framework.

2.7. Home Energy Gateways

 This use case describes the scenario of energy management of a home.
 The home energy gateway is another example of a proxy that interfaces
 with electrical appliances and other devices in a home.  This gateway
 can monitor and manage electrical equipment (e.g., refrigerator,
 heating/cooling, or washing machine) using one of the many protocols
 that are being developed for residential devices.
 Beyond simply metering, it's possible to implement energy saving
 policies based on time of day, occupancy, or energy pricing from the
 utility grid.  The EMAN information model can be applied to the
 energy management of a home.
 The essential properties of this use case are:
    o  Target devices: home energy gateway and smart meters in a home.
    o  How powered: any method.

Schoening, et al. Standards Track [Page 11] RFC 7603 EMAN Applicability Statement August 2015

    o  Reporting: The home energy gateway can collect power
       consumption of device in a home and possibly report the meter
       reading to the utility.

2.8. Data Center Devices

 This use case describes energy management of a data center.  Energy
 efficiency of data centers has become a fundamental challenge of data
 center operation, as data centers are big energy consumers and have
 an expensive infrastructure.  The equipment generates heat, and heat
 needs to be evacuated through an HVAC system.
 A typical data center network consists of a hierarchy of electrical
 energy objects.  At the bottom of the network hierarchy are servers
 mounted on a rack; these are connected to top-of-the-rack switches,
 which in turn are connected to aggregation switches and then to core
 switches.  Power consumption of all network elements, servers, and
 storage devices in the data center should be measured.  Energy
 management can be implemented on different aggregation levels, i.e.,
 at the network level, the Power Distribution Unit (PDU) level, and/or
 the server level.
 Beyond the network devices, storage devices, and servers, data
 centers contain Uninterruptable Power Systems (UPSs) to provide back-
 up power for the facility in the event of a power outage.  A UPS can
 provide backup power for many devices in a data center for a finite
 period of time.  Energy monitoring of energy storage capacity is
 vital from a data center network operations point of view.
 Presently, the UPS MIB can be useful in monitoring the battery
 capacity, the input load to the UPS, and the output load from the
 UPS.  Currently, there is no link between the UPS MIB and the ENTITY
 MIB.
 In addition to monitoring the power consumption of a data center,
 additional power characteristics should be monitored.  Some of these
 are dynamic variations in the input power supply from the grid,
 referred to as power quality metrics.  It can also be useful to
 monitor how efficiently the devices utilize power.
 Nameplate capacity of the data center can be estimated from the
 nameplate ratings (which indicate the maximum possible power draw) of
 IT equipment at a site.

Schoening, et al. Standards Track [Page 12] RFC 7603 EMAN Applicability Statement August 2015

 The essential properties of this use case are:
    o  Target devices: IT devices in a data center, such as network
       equipment, servers, and storage devices, as well as power and
       cooling infrastructure.
    o  How powered: any method, but commonly by one or more PDUs.
    o  Reporting: Devices may report on their own behalf or for other
       connected devices as described in other use cases.

2.9. Energy Storage Devices

 Energy storage devices can have two different roles: one type whose
 primary function is to provide power to another device (e.g., a UPS)
 and one type with a different primary function but that has energy
 storage as a component (e.g., a notebook).  This use case covers
 both.
 The energy storage can be a conventional battery or any other means
 to store electricity, such as a hydrogen cell.
 An internal battery can be a back-up or an alternative source of
 power to mains power.  As batteries have a finite capacity and
 lifetime, means for reporting the actual charge, age, and state of a
 battery are required.  An internal battery can be viewed as a
 component of a device and can be contained within the device from an
 ENTITY-MIB perspective.
 Battery systems are often used in remote locations such as mobile
 telecom towers.  For continuous operation, it is important to monitor
 the remaining battery life and raise an alarm when this falls below a
 threshold.
 The essential properties of this use case are:
    o  Target devices: devices that have an internal battery or
       external storage.
    o  How powered: from batteries or other storage devices.
    o  Reporting: The device reports on its power delivered and state.

Schoening, et al. Standards Track [Page 13] RFC 7603 EMAN Applicability Statement August 2015

2.10. Industrial Automation Networks

 Energy consumption statistics in the industrial sector are
 staggering.  The industrial sector alone consumes about half of the
 world's total delivered energy and is a significant user of
 electricity.  Thus, the need for optimization of energy usage in this
 sector is natural.
 Industrial facilities consume energy in process loads and non-process
 loads.
 The essential properties of this use case are:
    o  Target devices: devices used in an industrial sector.
    o  How powered: any method.
    o  Reporting: The Common Industrial Protocol (CIP) is commonly
       used for reporting energy for these devices.

2.11. Printers

 This use case describes the scenario of energy monitoring and
 management of printers.  Printers in this use case stand in for all
 imaging equipment, including Multi-function Devices (MFDs), scanners,
 fax machines, and mailing machines.
 Energy use of printers has been a long-standing industry concern, and
 sophisticated power management is common.  Printers often use a
 variety of low-power modes, particularly for managing energy-
 intensive thermo-mechanical components.  Printers also have long made
 extensive use of SNMP for end-user system interaction and for
 management generally, with cross-vendor management systems able to
 manage fleets of printers in enterprises.  Power consumption during
 active modes can vary widely, with high peak usage levels.
 Printers can expose detailed power state information, distinct from
 operational state information, with some printers reporting
 transition states between stable long-term states.  Many also support
 active setting of power states and policies, such as delay times,
 when inactivity automatically transitions the device to a lower power
 mode.  Other features include reporting on components, counters for
 state transitions, typical power levels by state, scheduling, and
 events/alarms.

Schoening, et al. Standards Track [Page 14] RFC 7603 EMAN Applicability Statement August 2015

 Some large printers also have a "Digital Front End", which is a
 computer that performs functions on behalf of the physical imaging
 system.  These typically have their own presence on the network and
 are sometimes separately powered.
 There are some unique characteristics of printers from the point of
 view energy management.  While the printer is not in use, there are
 timer-based low power states, which consume little power.  On the
 other hand, while the printer is printing or copying, the cylinder is
 heated so that power consumption is quite high but only for a short
 period of time.  Given this work load, periodic polling of power
 levels alone would not suffice.
 The essential properties of this use case are:
    o  Target devices: all imaging equipment.
    o  How powered: typically, AC from a wall outlet.
    o  Reporting: The devices report for themselves.

2.12. Demand Response

 The theme of demand response from a utility grid spans across several
 use cases.  In some situations, in response to time-of-day
 fluctuation of energy costs or sudden energy shortages due power
 outages, it may be important to respond and reduce the energy
 consumption of the network.
 From the EMAN use case perspective, the demand-response scenario can
 apply to a data center, building, or home.  Real-time energy
 monitoring is usually a prerequisite so that during a potential
 energy shortfall the EnMS can provide an active response.  The EnMS
 could shut down selected devices that are considered lower priority
 or uniformly reduce the power supplied to a class of devices.  For
 multisite data centers, it may be possible to formulate policies such
 as the follow-the-sun type of approach by scheduling the mobility of
 Virtual Machines (VMs) across data centers in different geographical
 locations.
 The essential properties of this use case are:
    o  Target devices: any device.
    o  How powered: traditional mains AC power.
    o  Reporting: Devices report in real time.

Schoening, et al. Standards Track [Page 15] RFC 7603 EMAN Applicability Statement August 2015

    o  Control: demand response based upon policy or priority.

3. Use Case Patterns

 The use cases presented above can be abstracted to the following
 broad patterns for energy objects.

3.1. Metering

  1. Energy objects that have the capability for internal metering
  1. Energy objects that are metered by an external device

3.2. Metering and Control

  1. Energy objects that do not supply power but can perform power

metering for other devices

  1. Energy objects that do not supply power but can perform both

metering and control for other devices

3.3. Power Supply, Metering, and Control

  1. Energy objects that supply power for other devices but do not

perform power metering for those devices

  1. Energy objects that supply power for other devices and also

perform power metering

  1. Energy objects that supply power for other devices and also

perform power metering and control for other devices

3.4. Multiple Power Sources

  1. Energy objects that have multiple power sources, with metering and

control performed by the same power source

  1. Energy objects that have multiple power sources supplying power to

the device with metering performed by one or more sources and

    control performed by another source

Schoening, et al. Standards Track [Page 16] RFC 7603 EMAN Applicability Statement August 2015

4. Relationship of EMAN to Other Standards

 The EMAN framework is tied to other standards and efforts that
 address energy monitoring and control.  EMAN leverages existing
 standards when possible, and it helps enable adjacent technologies
 such as Smart Grid.
 The standards most relevant and applicable to EMAN are listed below
 with a brief description of their objectives, the current state, and
 how that standard relates to EMAN.

4.1. Data Model and Reporting

4.1.1. IEC - CIM

 The International Electrotechnical Commission (IEC) has developed a
 broad set of standards for power management.  Among these, the most
 applicable to EMAN is IEC 61850, a standard for the design of
 electric utility automation.  The abstract data model defined in
 61850 is built upon and extends the Common Information Model (CIM).
 The complete 61850 CIM model includes over a hundred object classes
 and is widely used by utilities worldwide.
 This set of standards were originally conceived to automate control
 of a substation (a facility that transfers electricity from the
 transmission to the distribution system).  However, the extensive
 data model has been widely used in other domains, including Energy
 Management Systems (EnMS).
 IEC TC57 WG19 is an ongoing working group with the objective to
 harmonize the CIM data model and 61850 standards.
 Several concepts from IEC Standards have been reused in the EMAN
 documents.  In particular, AC Power Quality measurements have been
 reused from IEC 61850-7-4.  The concept of Accuracy Classes for
 measurement of power and energy has been adapted from ANSI C12.20 and
 IEC standards 62053-21 and 62053-22.

4.1.2. DMTF

 The Distributed Management Task Force (DMTF) has defined a Power
 State Management profile [DMTF-DSP1027] for managing computer systems
 using the DMTF's Common Information Model (CIM).  These
 specifications provide physical, logical, and virtual system
 management requirements for power-state control services.  The DMTF
 standard does not include energy monitoring.

Schoening, et al. Standards Track [Page 17] RFC 7603 EMAN Applicability Statement August 2015

 The Power State Management profile is used to describe and manage the
 Power State of computer systems.  This includes controlling the Power
 State of an entity for entering sleep mode, awakening, and rebooting.
 The EMAN framework references the DMTF Power Profile and Power State
 Set.

4.1.2.1. Common Information Model Profiles

 The DMTF uses CIM-based 'Profiles' to represent and manage power
 utilization and configuration of managed elements (note that this is
 not the 61850 CIM).  Key profiles for energy management are 'Power
 Supply' (DSP 1015), 'Power State' (DSP 1027), and 'Power Utilization
 Management' (DSP 1085).  These profiles define many features for the
 monitoring and configuration of a Power Managed Element's static and
 dynamic power saving modes, power allocation limits, and power
 states.
 Reduced power modes can be established as static or dynamic.  Static
 modes are fixed policies that limit power use or utilization.
 Dynamic power saving modes rely upon internal feedback to control
 power consumption.
 Power states are eight named operational and non-operational levels.
 These are On, Sleep-Light, Sleep-Deep, Hibernate, Off-Soft, and Off-
 Hard.  Power change capabilities provide immediate, timed interval,
 and graceful transitions between on, off, and reset power states.
 Table 3 of the Power State Profile defines the correspondence between
 the Advanced Configuration and Power Interface [ACPI] and DMTF power
 state models, although it is not necessary for a managed element to
 support ACPI.  Optionally, a TransitioningToPowerState property can
 represent power state transitions in progress.

4.1.2.2. DASH

 DMTF Desktop and Mobile Architecture for System Hardware [DASH]
 addresses managing heterogeneous desktop and mobile systems
 (including power) via in-band and out-of-band communications.  DASH
 uses the DMTF's Web Services for Management (WS-Management) and CIM
 data model to manage and control resources such as power, CPU, etc.
 Both in-service and out-of-service systems can be managed with the
 DASH specification in a fully secured remote environment.  Full power
 life-cycle management is possible using out-of-band management.

Schoening, et al. Standards Track [Page 18] RFC 7603 EMAN Applicability Statement August 2015

4.1.3. ODVA

 The Open DeviceNet Vendors Association (ODVA) is an association for
 industrial automation companies that defines the Common Industrial
 Protocol (CIP).  Within ODVA, there is a special interest group
 focused on energy and standardization and interoperability of energy-
 aware devices.
 The ODVA is developing an energy management framework for the
 industrial sector.  There are synergies and similar concepts between
 the ODVA and EMAN approaches to energy monitoring and management.
 ODVA defines a three-part approach towards energy management:
 awareness of energy usage, energy efficiency, and the exchange of
 energy with a utility or others.  Energy monitoring and management
 promote efficient consumption and enable automating actions that
 reduce energy consumption.
 The foundation of the approach is the information and communication
 model for entities.  An entity is a network-connected, energy-aware
 device that has the ability to either measure or derive its energy
 usage based on its native consumption or generation of energy, or
 report a nominal or static energy value.

4.1.4. Ecma SDC

 The Ecma International standard on Smart Data Centre [Ecma-SDC]
 defines semantics for management of entities in a data center such as
 servers, storage, and network equipment.  It covers energy as one of
 many functional resources or attributes of systems for monitoring and
 control.  It only defines messages and properties and does not
 reference any specific protocol.  Its goal is to enable
 interoperability of such protocols as SNMP, BACnet, and HTTP by
 ensuring a common semantic model across them.  Four power states are
 defined, Off, Sleep, Idle, and Active.  The standard does not include
 actual energy or power measurements.
 When used with EMAN, the SDC standard will provide a thin abstraction
 on top of the more detailed data model available in EMAN.

4.1.5. PWG

 The IEEE Industry Standards and Technology Organization (ISTO)
 Printer Working Group (PWG) defines open standards for printer-
 related protocols for the benefit of printer manufacturers and
 related software vendors.  The Printer WG covers power monitoring and
 management of network printers and imaging systems in the PWG Power
 Management Model for Imaging Systems [PWG5106.4].  Clearly, these

Schoening, et al. Standards Track [Page 19] RFC 7603 EMAN Applicability Statement August 2015

 devices are within the scope of energy management since they receive
 power and are attached to the network.  In addition, there is ample
 scope for power management since printers and imaging systems are not
 used that often.
 The IEEE-ISTO Printer Working Group (PWG) defines SNMP MIB modules
 for printer management and, in particular, a "PWG Power Management
 Model for Imaging Systems v1.0" [PWG5106.4] and a companion SNMP
 binding in the "PWG Imaging System Power MIB v1.0" [PWG5106.5].  This
 PWG model and MIB are harmonized with the DMTF CIM Infrastructure
 [DMTF-DSP0004] and DMTF CIM Power State Management Profile
 [DMTF-DSP1027] for power states and alerts.
 These MIB modules can be useful for monitoring the power and Power
 State of printers.  The EMAN framework takes into account the
 standards defined in the Printer Working Group.  The PWG may
 harmonize its MIBs with those from EMAN.  The PWG covers many topics
 in greater detail than EMAN, including those specific to imaging
 equipment.  The PWG also provides for vendor-specific extension
 states (beyond the standard DMTF CIM states).
 The IETF Printer MIB [RFC3805] is on the Standards Track, but that
 MIB module does not address power management.

4.1.6. ASHRAE

 In the U.S., there is an extensive effort to coordinate and develop
 standards related to the "Smart Grid".  The Smart Grid
 Interoperability Panel, coordinated by the government's National
 Institute of Standards and Technology, identified the need for a
 building side information model (as a counterpart to utility models)
 and specified this in Priority Action Plan (PAP) 17.  This was
 designated to be a joint effort by the American Society of Heating,
 Refrigerating and Air-Conditioning Engineers (ASHRAE) and the
 National Electrical Manufacturers Association (NEMA), both ANSI-
 approved Standards Development Organizations (SDOs).  The result is
 to be an information model, not a protocol.
 The ASHRAE effort [ASHRAE] addresses data used only within a building
 as well as data that may be shared with the grid, particularly as it
 relates to coordinating future demand levels with the needs of the
 grid.  The model is intended to be applied to any building type, both
 residential and commercial.  It is expected that existing protocols
 will be adapted to comply with the new information model, as would
 new protocols.

Schoening, et al. Standards Track [Page 20] RFC 7603 EMAN Applicability Statement August 2015

 There are four basic types of entities in the model: generators,
 loads, meters, and energy managers.  The metering part of the model
 overlaps to a large degree with the EMAN framework, though there are
 features unique to each.  The load part speaks to control
 capabilities well beyond what EMAN covers.  Details of generation and
 of the energy management function are outside of EMAN scope.
 A public review draft of the ASHRAE standard was released in July
 2012.  There are no apparent major conflicts between the two
 approaches, but there are areas where some harmonization is possible.

4.1.7. ANSI/CEA

 The Consumer Electronics Association (CEA) has approved ANSI/CEA-2047
 [ANSICEA] as a standard data model for Energy Usage Information.  The
 primary purpose is to enable home appliances and electronics to
 communicate energy usage information over a wide range of
 technologies with pluggable modules that contain the physical-layer
 electronics.  The standard can be used by devices operating on any
 home network including Wi-Fi, Ethernet, ZigBee, Z-Wave, and
 Bluetooth.  The Introduction to ANSI/CEA-2047 states that "this
 standard provides an information model for other groups to develop
 implementations specific to their network, protocol and needs."  It
 covers device identification, current power level, cumulative energy
 consumption, and provides for reporting time-series data.

4.1.8. ZigBee

 The ZigBee Smart Energy Profile 2.0 (SEP) effort [ZIGBEE] focuses on
 IP-based wireless communication to appliances and lighting.  It is
 intended to enable internal building energy management and provide
 for bidirectional communication with the power grid.
 ZigBee protocols are intended for use in embedded applications with
 low data rates and low power consumption.  ZigBee defines a general-
 purpose, inexpensive, self-organizing mesh network that can be used
 for industrial control, embedded sensing, medical data collection,
 smoke and intruder warning, building automation, home automation,
 etc.
 ZigBee is currently not an ANSI-recognized SDO.
 The EMAN framework addresses the needs of IP-enabled networks through
 the usage of SNMP, while ZigBee provides for completely integrated
 and inexpensive mesh solutions.

Schoening, et al. Standards Track [Page 21] RFC 7603 EMAN Applicability Statement August 2015

4.2. Measurement

4.2.1. ANSI C12

 The American National Standards Institute (ANSI) has defined a
 collection of power meter standards under ANSI C12.  The primary
 standards include communication protocols (C12.18, 21 and 22), data
 and schema definitions (C12.19), and measurement accuracy (C12.20).
 European equivalent standards are provided by IEC 62053-22.
 These very specific standards are oriented to the meter itself and
 are used by electricity distributors and producers.
 The EMAN framework [RFC7326] references the Accuracy Classes
 specified in ANSI C12.20.

4.2.2. IEC 62301

 IEC 62301, "Household electrical appliances - Measurement of standby
 power" [IEC62301], specifies a power-level measurement procedure.
 While nominally for appliances and low-power modes, its concepts
 apply to other device types and modes, and it is commonly referenced
 in test procedures for energy using products.
 While the standard is intended for laboratory measurements of devices
 in controlled conditions, aspects of it are informative to those
 implementing measurement in products that ultimately report via EMAN.

4.3. Other

4.3.1. ISO

 The International Organization for Standardization (ISO) [ISO] is
 developing an energy management standard, ISO 50001, to complement
 ISO 9001 for quality management and ISO 14001 for environmental
 management.  The intent is to facilitate the creation of energy
 management programs for industrial, commercial, and other entities.
 The standard defines a process for energy management at an
 organizational level.  It does not define the way in which devices
 report energy and consume energy.
 ISO 50001 is based on the common elements found in all of ISO's
 management system standards, assuring a high level of compatibility
 with ISO 9001 and ISO 14001.  ISO 50001 benefits include:
    o  Integrating energy efficiency into management practices and
       throughout the supply chain.

Schoening, et al. Standards Track [Page 22] RFC 7603 EMAN Applicability Statement August 2015

    o  Using energy management best practices and good energy
       management behaviors.
    o  Benchmarking, measuring, documenting, and reporting energy
       intensity improvements and their projected impact on reductions
       in greenhouse gas (GHG) emissions.
    o  Evaluating and prioritizing the implementation of new energy-
       efficient technologies.
 ISO 50001 has been developed by ISO project committee ISO TC 242,
 Energy Management.  EMAN is complementary to ISO 9001.

4.3.2. Energy Star

 The U.S. Environmental Protection Agency (EPA) and U.S. Department of
 Energy (DOE) jointly sponsor the Energy Star program [ESTAR].  The
 program promotes the development of energy efficient products and
 practices.
 To qualify as Energy Star, products must meet specific energy
 efficiency targets.  The Energy Star program also provides planning
 tools and technical documentation to encourage more energy-efficient
 building design.  Energy Star is a program; it is not a protocol or
 standard.
 For businesses and data centers, Energy Star offers technical support
 to help companies establish energy conservation practices.  Energy
 Star provides best practices for measuring current energy
 performance, goal setting, and tracking improvement.  The Energy Star
 tools offered include a rating system for building performance and
 comparative benchmarks.
 There is no immediate link between EMAN and Energy Star, one being a
 protocol and the other a set of recommendations to develop energy-
 efficient products.  However, Energy Star could include EMAN
 standards in specifications for future products, either as required
 or rewarded with some benefit.

4.3.3. Smart Grid

 The Smart Grid standards efforts underway in the United States are
 overseen by the U.S. National Institute of Standards and Technology
 [NIST].  NIST is responsible for coordinating a public-private
 partnership with key energy and consumer stakeholders in order to
 facilitate the development of Smart Grid standards.  These activities
 are monitored and facilitated by the Smart Grid Interoperability
 Panel (SGIP).  This group has working groups for specific topics

Schoening, et al. Standards Track [Page 23] RFC 7603 EMAN Applicability Statement August 2015

 including homes, commercial buildings, and industrial facilities as
 they relate to the grid.  A stated goal of the group is to harmonize
 any new standard with the IEC CIM and IEC 61850.
 When a working group detects a standard or technology gap, the team
 seeks approval from the SGIP for the creation of a Priority Action
 Plan (PAP), a private-public partnership to close the gap.  PAP 17 is
 discussed in Section 4.1.6.
 PAP 10 addresses "Standard Energy Usage Information".  Smart Grid
 standards will provide distributed intelligence in the network and
 allow enhanced load shedding.  For example, pricing signals will
 enable selective shutdown of non-critical activities during peak
 price periods.  Actions can be effected through both centralized and
 distributed management controls.
 There is an obvious functional link between Smart Grid and EMAN in
 the form of demand response even though the EMAN framework itself
 does not address any coordination with the grid.  As EMAN enables
 control, it can be used by an EnMS to accomplish demand response
 through translation of a signal from an outside entity.

5. Limitations

 EMAN addresses the needs of energy monitoring in terms of measurement
 and considers limited control capabilities of energy monitoring of
 networks.
 EMAN does not create a new protocol stack, but rather defines a data
 and information model useful for measuring and reporting energy and
 other metrics over SNMP.
 EMAN does not address questions regarding Smart Grid, electricity
 producers, and distributors.

6. Security Considerations

 EMAN uses SNMP and thus has the functionality of SNMP's security
 capabilities.  SNMPv3 [RFC3411] provides important security features
 such as confidentiality, integrity, and authentication.
 Section 10 of [RFC7460] and Section 6 of [RFC7461] mention that power
 monitoring and management MIBs may have certain privacy implications.
 These privacy implications are beyond the scope of this document.
 There may be additional privacy considerations specific to each use
 case; this document has not attempted to analyze these.

Schoening, et al. Standards Track [Page 24] RFC 7603 EMAN Applicability Statement August 2015

7. References

7.1. Normative References

 [RFC3411]   Harrington, D., Presuhn, R., and B. Wijnen, "An
             Architecture for Describing Simple Network Management
             Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
             DOI 10.17487/RFC3411, December 2002,
             <http://www.rfc-editor.org/info/rfc3411>.
 [RFC3621]   Berger, A. and D. Romascanu, "Power Ethernet MIB",
             RFC 3621, DOI 10.17487/RFC3621, December 2003,
             <http://www.rfc-editor.org/info/rfc3621>.

7.2. Informative References

 [ACPI]      ACPI, "Advanced Configuration and Power Interface
             Specification", Revision 5.0b, November 2013,
             <http://www.acpi.info/spec30b.htm>.
 [ANSICEA]   ANSI, "CEA 2047 CE Energy Usage Information (CE-EUI)",
             ANSI/CEA-2047, August 2014.
 [ASHRAE]    NIST, "ASHRAE SPC 201 P Information Page",
             <http://collaborate.nist.gov/twiki-sggrid/
             bin/view/SmartGrid/PAP17Information>.
 [BACnet]    "BACnet Webpage", <http://www.bacnet.org>.
 [DASH]      DMTF, "Desktop and Mobile Architecture for System
             Hardware", <http://www.dmtf.org/standards/mgmt/dash/>.
 [DMTF-DSP0004]
             DMTF, "Common Information Model (CIM) Infrastructure",
             DSP0004, Version 2.5.0, May 2009, <http://www.dmtf.org/
             standards/published_documents/DSP0004_2.5.0.pdf>.
 [DMTF-DSP1027]
             DMTF, "Power State Management Profile", DSP1027, Version
             2.0.0, December 2009, <http://www.dmtf.org/standards/
             published_documents/DSP1027_2.0.0.pdf>.
 [Ecma-SDC]  Ecma International, "Smart Data Centre Resource
             Monitoring and Control", Standard ECMA-400, Second
             Edition, June 2013, <http://www.ecma-international.org/
             publications/standards/Ecma-400.htm>.
 [ESTAR]     Energy Star, <http://www.energystar.gov/>.

Schoening, et al. Standards Track [Page 25] RFC 7603 EMAN Applicability Statement August 2015

 [IEC62301]  IEC, "Household electrical appliances - Measurement of
             standby power", IEC 62301:2011, Edition 2.0, January
             2011.
 [ISO]       ISO, "ISO launches ISO 50001 energy management standard",
             June 2011,
             <http://www.iso.org/iso/news.htm?refid=Ref1434>.
 [MODBUS]    Modbus-IDA, "MODBUS Application Protocol Specification",
             Version 1.1b, December 2006, <http://www.modbus.org/docs/
             Modbus_Application_Protocol_V1_1b.pdf>.
 [NIST]      NIST, "Smart Grid Homepage", August 2010,
             <http://www.nist.gov/smartgrid/>.
 [PWG5106.4] IEEE-ISTO, "PWG Power Management Model for Imaging
             Systems 1.0", PWG Candidate Standard 5106.4-2011,
             February 2011, <ftp://ftp.pwg.org/pub/pwg/candidates/
             cs-wimspower10-20110214-5106.4.pdf>.
 [PWG5106.5] IEEE-ISTO, "PWG Imaging System Power MIB v1.0", PWG
             Candidate Standard 5106.5-2011, February 2011.
 [RFC3805]   Bergman, R., Lewis, H., and I. McDonald, "Printer MIB
             v2", RFC 3805, DOI 10.17487/RFC3805, June 2004,
             <http://www.rfc-editor.org/info/rfc3805>.
 [RFC6933]   Bierman, A., Romascanu, D., Quittek, J., and M.
             Chandramouli, "Entity MIB (Version 4)", RFC 6933,
             DOI 10.17487/RFC6933, May 2013,
             <http://www.rfc-editor.org/info/rfc6933>.
 [RFC6988]   Quittek, J., Ed., Chandramouli, M., Winter, R., Dietz,
             T., and B. Claise, "Requirements for Energy Management",
             RFC 6988, DOI 10.17487/RFC6988, September 2013,
             <http://www.rfc-editor.org/info/rfc6988>.
 [RFC7326]   Parello, J., Claise, B., Schoening, B., and J. Quittek,
             "Energy Management Framework", RFC 7326,
             DOI 10.17487/RFC7326, September 2014,
             <http://www.rfc-editor.org/info/rfc7326>.
 [RFC7460]   Chandramouli, M., Claise, B., Schoening, B., Quittek, J.,
             and T. Dietz, "Monitoring and Control MIB for Power and
             Energy", RFC 7460, DOI 10.17487/RFC7460, March 2015,
             <http://www.rfc-editor.org/info/rfc7460>.

Schoening, et al. Standards Track [Page 26] RFC 7603 EMAN Applicability Statement August 2015

 [RFC7461]   Parello, J., Claise, B., and M. Chandramouli, "Energy
             Object Context MIB", RFC 7461, DOI 10.17487/RFC7461,
             March 2015, <http://www.rfc-editor.org/info/rfc7461>.
 [RFC7577]   Quittek, J., Winter, R., and T. Dietz, "Definition of
             Managed Objects for Battery Monitoring", RFC 7577,
             DOI 10.17487/RFC7577, July 2015,
             <http://www.rfc-editor.org/info/rfc7577>.
 [ZIGBEE]    "The ZigBee Alliance", <http://www.zigbee.org/>.

Acknowledgements

 Firstly, the authors thank Emmanuel Tychon for taking the lead on the
 initial draft and making substantial contributions to it.  The
 authors also thank Jeff Wheeler, Benoit Claise, Juergen Quittek,
 Chris Verges, John Parello, and Matt Laherty for their valuable
 contributions.  The authors also thank Kerry Lynn for the use case
 involving demand response.

Schoening, et al. Standards Track [Page 27] RFC 7603 EMAN Applicability Statement August 2015

Authors' Addresses

 Brad Schoening
 Independent Consultant
 44 Rivers Edge Drive
 Little Silver, NJ 07739
 United States
 Phone: +1 917 304 7190
 Email: brad.schoening@verizon.net
 Mouli Chandramouli
 Cisco Systems, Inc.
 Sarjapur Outer Ring Road
 Bangalore 560103
 India
 Phone: +91 80 4429 2409
 Email: moulchan@cisco.com
 Bruce Nordman
 Lawrence Berkeley National Laboratory
 1 Cyclotron Road, 90-2000
 Berkeley, CA  94720-8130
 United States
 Phone: +1 510 486 7089
 Email: bnordman@lbl.gov

Schoening, et al. Standards Track [Page 28]

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