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RFC 7460

Proposed STD
Pages: 69
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Monitoring and Control MIB for Power and Energy

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Internet Engineering Task Force (IETF)                   M. Chandramouli
Request for Comments: 7460                                     B. Claise
Category: Standards Track                            Cisco Systems, Inc.
ISSN: 2070-1721                                             B. Schoening
                                                  Independent Consultant
                                                              J. Quittek
                                                                T. Dietz
                                                        NEC Europe, Ltd.
                                                              March 2015


            Monitoring and Control MIB for Power and Energy

Abstract

   This document defines a subset of the Management Information Base
   (MIB) for power and energy monitoring of devices.

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/rfc7460.

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.

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Table of Contents

   1. Introduction ....................................................3
      1.1. Conventions Used in This Document ..........................3
   2. The Internet-Standard Management Framework ......................3
   3. Use Cases .......................................................4
   4. Terminology .....................................................4
   5. Architecture Concepts Applied to the MIB Modules ................5
      5.1. Energy Object Tables .......................................5
           5.1.1. ENERGY-OBJECT-MIB ...................................5
           5.1.2. POWER-ATTRIBUTES-MIB ................................7
           5.1.3. UML Diagram .........................................9
      5.2. Energy Object Identity ....................................12
      5.3. Power State ...............................................12
           5.3.1. Power State Set ....................................13
      5.4. Energy Object Usage Information ...........................13
      5.5. Optional Power Usage Attributes ...........................14
      5.6. Optional Energy Measurement ...............................14
      5.7. Fault Management ..........................................18
   6. Discovery ......................................................18
   7. Link with the Other IETF MIBs ..................................19
      7.1. Link with the ENTITY-MIB and the ENTITY-SENSOR MIB ........19
      7.2. Link with the ENTITY-STATE MIB ............................20
      7.3. Link with the POWER-OVER-ETHERNET MIB .....................21
      7.4. Link with the UPS MIB .....................................21
      7.5. Link with the LLDP and LLDP-MED MIBs ......................22
   8. Structure of the MIB ...........................................23
   9. MIB Definitions ................................................24
      9.1. The IANAPowerStateSet-MIB Module ..........................24
      9.2. The ENERGY-OBJECT-MIB MIB Module ..........................27
      9.3. The POWER-ATTRIBUTES-MIB MIB Module .......................50
   10. Security Considerations .......................................63
   11. IANA Considerations ...........................................64
      11.1. IANAPowerStateSet-MIB Module .............................65
   12. References ....................................................65
      12.1. Normative References .....................................65
      12.2. Informative References ...................................66
   Acknowledgments ...................................................68
   Contributors ......................................................68
   Authors' Addresses ................................................69

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1.  Introduction

   This document defines a subset of the Management Information Base
   (MIB) for use in energy management of devices within or connected to
   communication networks.  The MIB modules in this document are
   designed to provide a model for energy management, which includes
   monitoring for Power State and energy consumption of networked
   elements.  This MIB takes into account the "Energy Management
   Framework" [RFC7326], which, in turn, is based on the "Requirements
   for Energy Management" [RFC6988].

   Energy management can be applied to devices in communication
   networks.  Target devices for this specification include (but are not
   limited to) routers, switches, Power over Ethernet (PoE) endpoints,
   protocol gateways for building management systems, intelligent
   meters, home energy gateways, hosts and servers, sensor proxies, etc.
   Target devices and the use cases for Energy Management are discussed
   in Energy Management Applicability Statement [EMAN-AS].

   Where applicable, device monitoring extends to the individual
   components of the device and to any attached dependent devices.  For
   example, a device can contain components that are independent from a
   Power State point of view, such as line cards, processor cards, hard
   drives.  A device can also have dependent attached devices, such as a
   switch with PoE endpoints or a power distribution unit with attached
   endpoints.

1.1.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in RFC
   2119 [RFC2119].

2.  The Internet-Standard Management Framework

   For a detailed overview of the documents that describe the current
   Internet-Standard Management Framework, please refer to section 7 of
   RFC 3410 [RFC3410].

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  MIB objects are generally
   accessed through the Simple Network Management Protocol (SNMP).
   Objects in the MIB are defined using the mechanisms defined in the
   Structure of Management Information (SMI).  This memo specifies MIB
   modules that are compliant to SMIv2, which is described in STD 58,
   RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
   [RFC2580].

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3.  Use Cases

   Requirements for power and energy monitoring for networking devices
   are specified in [RFC6988].  The requirements in [RFC6988] cover
   devices typically found in communications networks, such as switches,
   routers, and various connected endpoints.  For a power monitoring
   architecture to be useful, it should also apply to facility meters,
   power distribution units, gateway proxies for commercial building
   control, home automation devices, and devices that interface with the
   utility and/or smart grid.  Accordingly, the scope of the MIB modules
   in this document are broader than that specified in [RFC6988].
   Several use cases for Energy Management have been identified in the
   "Energy Management (EMAN) Applicability Statement" [EMAN-AS].

4.  Terminology

   Please refer to [RFC7326] for the definitions of the following
   terminology used in this document.

      Energy Management
      Energy Management System (EnMS)
      Energy Monitoring
      Energy Control
      electrical equipment
      non-electrical equipment (mechanical equipment)
      device
      component
      power inlet
      power outlet
      energy
      power
      demand
      provide energy
      receive energy
      meter (energy meter)
      battery
      Power Interface
      Nameplate Power
      Power Attributes
      Power Quality
      Power State
      Power State Set

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5.  Architecture Concepts Applied to the MIB Modules

   This section describes the concepts specified in the Energy
   Management Framework [RFC7326] that pertain to power usage, with
   specific information related to the MIB module specified in this
   document.  This subsection maps concepts developed in the Energy
   Management Framework [RFC7326].

   The Energy Monitoring MIB has two independent MIB modules: ENERGY-
   OBJECT-MIB and POWER-ATTRIBUTES-MIB.  The first, ENERGY-OBJECT-MIB,
   is focused on measurement of power and energy.  The second, POWER-
   ATTRIBUTES-MIB, is focused on power quality measurements for Energy
   Objects.

   Devices and their sub-components can be modeled using the containment
   tree of the ENTITY-MIB [RFC6933].

5.1.  Energy Object Tables

5.1.1.  ENERGY-OBJECT-MIB

   The ENERGY-OBJECT-MIB module consists of five tables.

   The first table is the eoMeterCapabilitiesTable.  It indicates the
   instrumentation available for each Energy Object.  Entries in this
   table indicate which other tables from the ENERGY-OBJECT-MIB and
   POWER-ATTRIBUTES-MIB are available for each Energy Object.  The
   eoMeterCapabilitiesTable is indexed by entPhysicalIndex [RFC6933].

   The second table is the eoPowerTable.  It reports the power
   consumption of each Energy Object as well as the units, sign,
   measurement accuracy, and related objects.  The eoPowerTable is
   indexed by entPhysicalIndex.

   The third table is the eoPowerStateTable.  For each Energy Object, it
   reports information and statistics about the supported Power States.
   The eoPowerStateTable is indexed by entPhysicalIndex and
   eoPowerStateIndex.

   The fourth table is the eoEnergyParametersTable.  The entries in this
   table configure the parameters of energy and demand measurement
   collection.  This table is indexed by eoEnergyParametersIndex.

   The fifth table is the eoEnergyTable.  The entries in this table
   provide a log of the energy and demand information.  This table is
   indexed by eoEnergyParametersIndex.

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   A "smidump-style" tree presentation of the MIB modules contained in
   the document is presented.  The meaning of the three symbols is a
   compressed representation of the object's MAX-ACCESS clause, which
   may have the following values:

              "not-accessible"         ->  "---"
              "accessible-for-notify"  ->  "--n"
              "read-only"              ->  "r-n"
              "read-write"             ->  "rwn"

      eoMeterCapabilitiesTable(1)
       |
       +---eoMeterCapabilitiesEntry(1)[entPhysicalIndex]
       |   |
       |   +---r-n  BITS             eoMeterCapability
       |

      eoPowerTable(2)
       |
       +---eoPowerEntry(1) [entPhysicalIndex]
       |   |
       |   +---r-n Integer32         eoPower(1)
       |   +-- r-n Unsigned32        eoPowerNamePlate(2)
       |   +-- r-n UnitMultiplier    eoPowerUnitMultiplier(3)
       |   +-- r-n Integer32         eoPowerAccuracy(4)
       |   +-- r-n INTEGER           eoPowerMeasurementCaliber(5)
       |   +-- r-n INTEGER           eoPowerCurrentType(6)
       |   +-- r-n TruthValue        eoPowerMeasurementLocal(7)
       |   +-- rwn PowerStateSet     eoPowerAdminState(8)
       |   +-- r-n PowerStateSet     eoPowerOperState(9)
       |   +-- r-n OwnerString       eoPowerStateEnterReason(10)
       |
       |
       |
       +---eoPowerStateTable(3)
       |
       |      +--eoPowerStateEntry(1)
       |      |     [entPhysicalIndex, eoPowerStateIndex]
       |      |
       |      +-- --n PowerStateSet eoPowerStateIndex(1)
       |      +-- r-n Integer32         eoPowerStateMaxPower(2)
       |      +-- r-n UnitMultiplier
       |                      eoPowerStatePowerUnitMultiplier(3)
       |      +-- r-n TimeTicks         eoPowerStateTotalTime(4)
       |      +-- r-n Counter32         eoPowerStateEnterCount(5)
       |
       +eoEnergyParametersTable(4)
       |

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       +---eoEnergyParametersEntry(1) [eoEnergyParametersIndex]
       |
       |   +-- --n PhysicalIndex  eoEnergyObjectIndex(1)
       |   +   r-n Integer32      eoEnergyParametersIndex(2)
       |   +-- rwn TimeInterval   eoEnergyParametersIntervalLength(3)
       |   +-- rwn Unsigned32     eoEnergyParametersIntervalNumber(4)
       |   +-- rwn INTEGER        eoEnergyParametersIntervalMode(5)
       |   +-- rwn TimeInterval   eoEnergyParametersIntervalWindow(6)
       |   +-- rwn Unsigned32     eoEnergyParametersSampleRate(7)
       |   +-- rwn StorageType    eoEnergyParametersStorageType(8)
       |   +-- rwn RowStatus      eoEnergyParametersStatus(9)
       |
       +eoEnergyTable(5)
       |
       +---eoEnergyEntry(1)
       |    [eoEnergyParametersIndex,eoEnergyCollectionStartTime]
       |
       |   +-- r-n TimeTicks      eoEnergyCollectionStartTime(1)
       |   +-- r-n Unsigned32     eoEnergyConsumed(2)
       |   +-- r-n Unsigned32     eoEnergyProvided(3)
       |   +-- r-n Unsigned32     eoEnergyStored(4)
       |   +-- r-n UnitMultiplier eoEnergyUnitMultiplier(5)
       |   +-- r-n Integer32      eoEnergyAccuracy(6)
       |   +-- r-n Unsigned32     eoEnergyMaxConsumed(7)
       |   +-- r-n Unsigned32     eoEnergyMaxProduced(8)
       |   +-- r-n TimeTicks      eoEnergyDiscontinuityTime(9)

5.1.2.  POWER-ATTRIBUTES-MIB

   The POWER-ATTRIBUTES-MIB module consists of three tables.

   The first table is the eoACPwrAttributesTable.  It indicates the
   power quality available for each Energy Object.  The
   eoACPwrAttributesTable is indexed by entPhysicalIndex [RFC6933].

   The second table is the eoACPwrAttributesDelPhaseTable.  The entries
   in this table configure the parameters of energy and demand
   measurement collection.  This table is indexed by
   eoEnergyParametersIndex.

   The third table is the eoACPwrAttributesWyePhaseTable.  For each
   Energy Object, it reports information and statistics about the
   supported Power States.  The eoPowerStateTable is indexed by
   entPhysicalIndex and eoPowerStateIndex.

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      eoACPwrAttributesTable(1)
        |
        +---eoACPwrAttributesEntry(1) [ entPhysicalIndex]
        |   |
        |   +---r-n INTEGER    eoACPwrAttributesConfiguration(1)
        |   +-- r-n Integer32  eoACPwrAttributesAvgVoltage(2)
        |   +-- r-n Unsigned32 eoACPwrAttributesAvgCurrent(3)
        |   +-- r-n Integer32  eoACPwrAttributesFrequency(4)
        |   +-- r-n UnitMultiplier
        |                eoACPwrAttributesPowerUnitMultiplier(5)
        |   +-- r-n Integer32  eoACPwrAttributesPowerAccuracy(6)
        |   +-- r-n Integer32
        |                   eoACPwrAttributesTotalActivePower(7)
        |   +-- r-n Integer32
        |                 eoACPwrAttributesTotalReactivePower(8)
        |   +-- r-n Integer32
        |                 eoACPwrAttributesTotalApparentPower(9)
        |   +-- r-n Integer32
        |                  eoACPwrAttributesTotalPowerFactor(10)
        |   +-- r-n Integer32  eoACPwrAttributesThdCurrent(11)
        |   +-- r-n Integer32  eoACPwrAttributesThdVoltage(12)
        |
        +eoACPwrAttributesDelPhaseTable(2)
        |
        +-- eoACPwrAttributesDelPhaseEntry(1)
        |     |   [entPhysicalIndex, eoACPwrAttributesDelPhaseIndex]
        |     |
        |     +-- r-n Integer32
        |     |    eoACPwrAttributesDelPhaseIndex(1)
        |     +-- r-n Integer32
        |     |    eoACPwrAttributesDelPhaseToNextPhaseVoltage(2)
        |     +-- r-n Integer32
        |     | eoACPwrAttributesDelThdPhaseToNextPhaseVoltage(3)
        |     |
        +eoACPwrAttributesWyePhaseTable(3)
        |
        +-- eoACPwrAttributesWyePhaseEntry(1)
        |     |   [entPhysicalIndex, eoACPwrAttributesWyePhaseIndex]
        |     |
        |     +-- r-n Integer32
        |     |     eoACPwrAttributesWyePhaseIndex(1)
        |     +-- r-n Integer32
        |     |     eoACPwrAttributesWyePhaseToNeutralVoltage(2)
        |     +-- r-n Integer32
        |     |     eoACPwrAttributesWyeCurrent(3)
        |     +-- r-n Integer32
        |     |     eoACPwrAttributesWyeActivePower(4)

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        |     +-- r-n Integer32
        |     |     eoACPwrAttributesWyeReactivePower(5)
        |     +-- r-n Integer32
        |     |     eoACPwrAttributesWyeApparentPower(6)
        |     +-- r-n Integer32
        |     |     eoACPwrAttributesWyePowerFactor(7)
        |     +-- r-n Integer32
        |     |     eoACPwrAttributesWyeThdCurrent(9)
        |     +-- r-n Integer32
        |     |     eoACPwrAttributesWyeThdPhaseToNeutralVoltage(10)

5.1.3.  UML Diagram

   A Unified Modeling Language (UML) diagram representation of the MIB
   objects in the two MIB modules, ENERGY-OBJECT-MIB and POWER-
   ATTRIBUTES-MIB, is presented.

         +-----------------------+
         | Meter Capabilities    |
         | --------------------- |
         | eoMeterCapability     |
         +-----------------------+

         +-----------------------+
   |---> |  Energy Object ID (*) |
   |     | --------------------- |
   |     | entPhysicalIndex      |
   |     | entPhysicalClass      |
   |     | entPhysicalName       |
   |     | entPhysicalUUID       |
   |     +-----------------------+
   |
   |     +---------------------------+
   |---- |_ Power Table              |
   |     | ------------------------- |
   |     | eoPower                   |
   |     | eoPowerNamePlate          |
   |     | eoPowerUnitMultiplier     |
   |     | eoPowerAccuracy           |
   |     | eoPowerMeasurementCaliber |
   |     | eoPowerCurrentType        |
   |     | eoPowerMeasurementLocal   |
   |     | eoPowerAdminState         |
   |     | eoPowerOperState          |
   |     | eoPowerStateEnterReason   |
   |     +---------------------------+

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   |     +---------------------------------+
   |---- |_Energy Object State Statistics  |
   |     |-------------------------------- |
   |     | eoPowerStateIndex               |
   |     | eoPowerStateMaxPower            |
   |     | eoPowerStatePowerUnitMultiplier |
   |     | eoPowerStateTotalTime           |
   |     | eoPowerStateEnterCount          |
   |     +---------------------------------+
   |
   |     +----------------------------------+
   |---- |    Energy ParametersTable        |
   |     | -------------------------------- |
   |     | eoEnergyObjectIndex              |
   |     | eoEnergyParametersIndex          |
   |     | eoEnergyParametersIntervalLength |
   |     | eoEnergyParametersIntervalNumber |
   |     | eoEnergyParametersIntervalMode   |
   |     | eoEnergyParametersIntervalWindow |
   |     | eoEnergyParametersSampleRate     |
   |     | eoEnergyParametersStorageType    |
   |     | eoEnergyParametersStatus         |
   |     +----------------------------------+
   |
   |     +----------------------------------+
   |---- |    Energy Table                  |
         | -------------------------------- |
         | eoEnergyCollectionStartTime      |
         | eoEnergyConsumed                 |
         | eoEnergyProvided                 |
         | eoEnergyStored                   |
         | eoEnergyUnitMultiplier           |
         | eoEnergyAccuracy                 |
         | eoEnergyMaxConsumed              |
         | eoEnergyMaxProduced              |
         | eoDiscontinuityTime              |
         +----------------------------------+

      Figure 1: UML Diagram for energyObjectMib

    (*) Compliance with the ENERGY-OBJECT-CONTEXT-MIB

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         +-----------------------+
   |---> |  Energy Object ID (*) |
   |     | --------------------- |
   |     | entPhysicalIndex      |
   |     | entPhysicalName       |
   |     | entPhysicalUUID       |
   |     +-----------------------+
   |     +--------------------------------------+
   |---- |  Power Attributes                    |
   |     | ------------------------------------ |
   |     | eoACPwrAttributesConfiguration       |
   |     | eoACPwrAttributesAvgVoltage          |
   |     | eoACPwrAttributesAvgCurrent          |
   |     | eoACPwrAttributesFrequency           |
   |     | eoACPwrAttributesPowerUnitMultiplier |
   |     | eoACPwrAttributesPowerAccuracy       |
   |     | eoACPwrAttributesTotalActivePower    |
   |     | eoACPwrAttributesTotalReactivePower  |
   |     | eoACPwrAttributesTotalApparentPower  |
   |     | eoACPwrAttributesTotalPowerFactor    |
   |     | eoACPwrAttributesThdCurrent          |
   |     | eoACPwrAttributesThdVoltage          |
   |     +--------------------------------------+
   |     +------------------------------------------------+
   |---- |  AC Input DEL Configuration                    |
   |     | ---------------------------------------------- |
   |     | eoACPwrAttributesDelPhaseIndex                 |
   |     | eoACPwrAttributesDelPhaseToNextPhaseVoltage    |
   |     | eoACPwrAttributesDelThdPhaseToNextPhaseVoltage |
   |     +------------------------------------------------+
   |
   |     +----------------------------------------------+
   |---- |  AC Input WYE Configuration                  |
         | -------------------------------------------- |
         | eoACPwrAttributesWyePhaseIndex               |
         | eoACPwrAttributesWyePhaseToNeutralVoltage    |
         | eoACPwrAttributesWyeCurrent                  |
         | eoACPwrAttributesWyeActivePower              |
         | eoACPwrAttributesWyeReactivePower            |
         | eoACPwrAttributesWyeApparentPower            |
         | eoACPwrAttributesWyePowerFactor              |
         | eoACPwrAttributesWyeThdCurrent               |
         | eoACPwrAttributesWyeThdPhaseToNeutralVoltage |
         +----------------------------------------------+

        Figure 2: UML Diagram for the POWER-ATTRIBUTES-MIB

        (*) Compliance with the ENERGY-OBJECT-CONTEXT-MIB

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5.2.  Energy Object Identity

   The Energy Object identity information is specified in the ENERGY-
   OBJECT-CONTEXT-MIB module [RFC7461] primary table, i.e., the eoTable.
   In this table, Energy Object context such as domain, role
   description, and importance are specified.  In addition, the ENERGY-
   OBJECT-CONTEXT-MIB module specifies the relationship between Energy
   Objects.  There are several possible relationships between Energy
   Objects, such as meteredBy, metering, poweredBy, powering,
   aggregatedBy, and aggregating as defined in the IANA-ENERGY-RELATION-
   MIB module [RFC7461].

5.3.  Power State

   An Energy Object may have energy-conservation modes called "Power
   States".  There may be several intermediate energy-saving modes
   between the ON and OFF states of a device.

   Power States, which represent universal states of power management of
   an Energy Object, are specified by the eoPowerState MIB object.  The
   actual Power State is specified by the eoPowerOperState MIB object,
   while the eoPowerAdminState MIB object specifies the Power State
   requested for the Energy Object.  The difference between the values
   of eoPowerOperState and eoPowerAdminState indicates that the Energy
   Object is busy transitioning from eoPowerAdminState into the
   eoPowerOperState, at which point it will update the content of
   eoPowerOperState.  In addition, the possible reason for a change in
   Power State is reported in eoPowerStateEnterReason.  Regarding
   eoPowerStateEnterReason, management stations and Energy Objects
   should support any format of the owner string dictated by the local
   policy of the organization.  It is suggested that this name contain
   at least the reason for the transition change, and one or more of the
   following: IP address, management station name, network manager's
   name, location, or phone number.

   The MIB objects eoPowerOperState, eoPowerAdminState, and
   eoPowerStateEnterReason are contained in the eoPowerTable.

   eoPowerStateTable enumerates the maximum power usage in watts for
   every single supported Power State of each Power State Set supported
   by the Energy Object.  In addition, eoPowerStateTable provides
   additional statistics such as eoPowerStateEnterCount, i.e., the
   number of times an entity has visited a particular Power State, and
   eoPowerStateTotalTime, i.e., the total time spent in a particular
   Power State of an Energy Object.

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5.3.1.  Power State Set

   There are several standards and implementations of Power State Sets.
   An Energy Object can support one or multiple Power State Set
   implementations concurrently.

   There are currently three Power State Sets defined:

      IEEE1621(256) - [IEEE1621]
      DMTF(512)     - [DMTF]
      EMAN(768)     - [RFC7326]

   The Power State Sets are listed in [RFC7326] along with each Power
   State within the Power Set.  The Power State Sets are specified by
   the PowerStateSet Textual Convention (TC) as an IANA-maintained MIB
   module.  The initial version of this MIB module is specified in this
   document.

5.4.  Energy Object Usage Information

   For an Energy Object, power usage is reported using eoPower.  The
   magnitude of measurement is based on the eoPowerUnitMultiplier MIB
   variable, based on the UnitMultiplier TC.  Power measurement
   magnitude should conform to the IEC 62053-21 [IEC.62053-21] and IEC
   62053-22 [IEC.62053-22] definition of unit multiplier for the SI
   units of measure (where SI is the International System of Units).
   Measured values are represented in SI units obtained by BaseValue *
   10 raised to the power of the unit multiplier.

   For example, if current power usage of an Energy Object is 3, it
   could be 3 W, 3 mW, 3 kW, or 3 MW, depending on the value of
   eoPowerUnitMultiplier.  Note that other measurements throughout the
   two MIB modules in this document use the same mechanism, including
   eoPowerStatePowerUnitMultiplier, eoEnergyUnitMultiplier, and
   oACPwrAttributesPowerUnitMultiplier.

   In addition to knowing the usage and magnitude, it is useful to know
   how an eoPower measurement was obtained.  A Network Management System
   (NMS) can use this to account for the accuracy and nature of the
   reading between different implementations.  eoPowerMeasurementLocal
   describes whether the measurements were made at the device itself or
   from a remote source.  The eoPowerMeasurementCaliber describes the
   method that was used to measure the power and can distinguish actual
   or estimated values.  There may be devices in the network that may
   not be able to measure or report power consumption.  For those
   devices, the object eoPowerMeasurementCaliber shall report that the
   measurement mechanism is "unavailable" and the eoPower measurement
   shall be "0".

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   The nameplate power rating of an Energy Object is specified in
   eoPowerNameplate MIB object.

5.5.  Optional Power Usage Attributes

   The optional POWER-ATTRIBUTES-MIB module can be implemented to
   further describe power attributes usage measurement.  The POWER-
   ATTRIBUTES-MIB module is aligned with the IEC 61850 7-2 standard to
   describe alternating current (AC) measurements.

   The POWER-ATTRIBUTES-MIB module contains a primary table,
   eoACPwrAttributesTable, that defines power attributes measurements
   for supported entPhysicalIndex entities, as a sparse extension of the
   eoPowerTable (with entPhysicalIndex as primary index).  This
   eoACPwrAttributesTable table contains such information as the
   configuration (single phase, DEL 3 phases, WYE 3 phases), frequency,
   power accuracy, total active/reactive power/apparent power, amperage,
   and voltage.

   In case of three-phase power, an additional table is populated with
   power attributes measurements per phase (hence, double indexed by the
   entPhysicalIndex and a phase index).  This table, describes
   attributes specific to either WYE or DEL configurations.

   In a DEL configuration, the eoACPwrAttributesDelPhaseTable describes
   the phase-to-phase power attributes measurements, i.e., voltage.  In
   a DEL configuration, the current is equal in all three phases.

   In a WYE configuration, the eoACPwrAttributesWyePhaseTable describes
   the phase-to-neutral power attributes measurements, i.e., voltage,
   current, active/reactive/apparent power, and power factor.

5.6.  Optional Energy Measurement

   It is only relevant to measure energy and demand when there are
   actual power measurements obtained from measurement hardware.  If the
   eoPowerMeasurementCaliber MIB object has values of unavailable,
   unknown, estimated, or presumed, then the energy and demand values
   are not useful.

   Two tables are introduced to characterize energy measurement of an
   Energy Object: eoEnergyTable and eoEnergyParametersTable.  Both
   energy and demand information can be represented via the
   eoEnergyTable.  Demand information can be represented.  The
   eoEnergyParametersTable consists of the parameters defining
   eoEnergyParametersIndex -- an index for the Energy Object,
   eoEnergyObjectIndex -- linked to the entPhysicalIndex of the Energy
   Object, the duration of measurement intervals in seconds,

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   (eoEnergyParametersIntervalLength), the number of successive
   intervals to be stored in the eoEnergyTable,
   (eoEnergyParametersIntervalNumber), the type of measurement technique
   (eoEnergyParametersIntervalMode), and a sample rate used to calculate
   the average (eoEnergyParametersSampleRate).  Judicious choice of the
   sampling rate will ensure accurate measurement of energy while not
   imposing an excessive polling burden.

   There are three eoEnergyParametersIntervalMode types used for energy
   measurement collection: period, sliding, and total.  The choices of
   the three different modes of collection are based on IEC standard
   61850-7-4 [IEC.61850-7-4].  Note that multiple
   eoEnergyParametersIntervalMode types MAY be configured
   simultaneously.  It is important to note that for a given Energy
   Object, multiple modes (periodic, total, sliding window) of energy
   measurement collection can be configured with the use of
   eoEnergyParametersIndex.  However, simultaneous measurement in
   multiple modes for a given Energy Object depends on the Energy Object
   capability.

   These three eoEnergyParametersIntervalMode types are illustrated by
   the following three figures, for which:

      - The horizontal axis represents the current time, with the symbol
        <--- L ---> expressing the eoEnergyParametersIntervalLength and
        the eoEnergyCollectionStartTime is represented by S1, S2, S3,
        S4, eoEnergyParametersIntervalNumber.

      - The vertical axis represents the time interval of sampling and
        the value of eoEnergyConsumed can be obtained at the end of the
        sampling period.  The symbol =========== denotes the duration of
        the sampling period.

         |             |             | =========== |
         |============ |             |             |
         |             |             |             |
         |             |============ |             |
         |             |             |             |
         | <--- L ---> | <--- L ---> | <--- L ---> |
         |             |             |             |
        S1            S2            S3             S4

        Figure 3: Period eoEnergyParametersIntervalMode

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   A eoEnergyParametersIntervalMode type of 'period' specifies non-
   overlapping periodic measurements.  Therefore, the next
   eoEnergyCollectionStartTime is equal to the previous
   eoEnergyCollectionStartTime plus eoEnergyParametersIntervalLength.
   S2=S1+L; S3=S2+L, ...

                  |============ |
                  |             |
                  | <--- L ---> |
                  |             |
                  |   |============ |
                  |   |             |
                  |   | <--- L ---> |
                  |   |             |
                  |   |   |============ |
                  |   |   |             |
                  |   |   | <--- L ---> |
                  |   |   |             |
                  |   |   |   |============ |
                  |   |   |   |             |
                  |   |   |   | <--- L ---> |
                 S1   |   |   |             |
                      |   |   |             |
                      |   |   |             |
                     S2   |   |             |
                          |   |             |
                          |   |             |
                         S3   |             |
                              |             |
                              |             |
                             S4

           Figure 4: Sliding eoEnergyParametersIntervalMode

   A eoEnergyParametersIntervalMode type of 'sliding' specifies
   overlapping periodic measurements.

   |                          |
   |========================= |
   |                          |
   |                          |
   |                          |
   |  <--- Total length --->  |
   |                          |
                    S1

   Figure 5: Total eoEnergyParametersIntervalMode

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   An eoEnergyParametersIntervalMode type of 'total' specifies a
   continuous measurement since the last reset.  The value of
   eoEnergyParametersIntervalNumber should be (1) one and
   eoEnergyParametersIntervalLength is ignored.

   The eoEnergyParametersStatus is used to start and stop energy usage
   logging.  The status of this variable is "active" when all the
   objects in eoEnergyParametersTable are appropriate, which, in turn,
   indicates whether or not eoEnergyTable entries exist.  Finally, the
   eoEnergyParametersStorageType variable indicates the storage type for
   this row, i.e., whether the persistence is maintained across a device
   reload.

   The eoEnergyTable consists of energy measurements of
   eoEnergyConsumed, eoEnergyProvided and eoEnergyStored, unit scale of
   measured energy with eoEnergyUnitMultiplier, percentage accuracy with
   eoEnergyAccuracy, and the maximum observed energy within a window in
   eoEnergyMaxConsumed, eoEnergyMaxProduced, and
   eoEnergyDiscontinuityTime.

   Measurements of the total energy consumed by an Energy Object may
   suffer from interruptions in the continuous measurement of energy
   consumption.  In order to indicate such interruptions, the object
   eoEnergyDiscontinuityTime is provided for indicating the time of the
   last interruption of total energy measurement.
   eoEnergyDiscontinuityTime shall indicate the sysUpTime [RFC3418] when
   the device was reset.

   The following example illustrates the eoEnergyTable and
   eoEnergyParametersTable:

   First, in order to estimate energy, a time interval to sample energy
   should be specified, i.e., eoEnergyParametersIntervalLength can be
   set to "900 seconds" or 15 minutes and the number of consecutive
   intervals over which the maximum energy is calculated
   (eoEnergyParametersIntervalNumber) as "10".  The sampling rate
   internal to the Energy Object for measurement of power usage
   (eoEnergyParametersSampleRate) can be "1000 milliseconds", as set by
   the Energy Object as a reasonable value.  Then, the
   eoEnergyParametersStatus is set to active to indicate that the Energy
   Object should start monitoring the usage per the eoEnergyTable.

   The indices for the eoEnergyTable are eoEnergyParametersIndex, which
   identifies the index for the setting of energy measurement collection
   Energy Object, and eoEnergyCollectionStartTime, which denotes the
   start time of the energy measurement interval based on sysUpTime
   [RFC3418].  The value of eoEnergyComsumed is the measured energy
   consumption over the time interval specified

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   (eoEnergyParametersIntervalLength) based on the Energy Object
   internal sampling rate (eoEnergyParametersSampleRate).  While
   choosing the values for the eoEnergyParametersIntervalLength and
   eoEnergyParametersSampleRate, it is recommended to take into
   consideration both the network element resources adequate to process
   and store the sample values and the mechanism used to calculate the
   eoEnergyConsumed.  The units are derived from eoEnergyUnitMultiplier.
   For example, eoEnergyConsumed can be "100" with
   eoEnergyUnitMultiplier equal to 0, the measured energy consumption of
   the Energy Object is 100 watt-hours.  The eoEnergyMaxConsumed is the
   maximum energy observed and that can be "150 watt-hours".

   The eoEnergyTable has a buffer to retain a certain number of
   intervals, as defined by eoEnergyParametersIntervalNumber.  If the
   default value of "10" is kept, then the eoEnergyTable contains 10
   energy measurements, including the maximum.

   Here is a brief explanation of how the maximum energy can be
   calculated.  The first observed energy measurement value is taken to
   be the initial maximum.  With each subsequent measurement, based on
   numerical comparison, maximum energy may be updated.  The maximum
   value is retained as long as the measurements are taking place.
   Based on periodic polling of this table, an NMS could compute the
   maximum over a longer period, e.g., a month, 3 months, or a year.

5.7.  Fault Management

   [RFC6988] specifies requirements about Power States such as "the
   current Power State", "the time of the last state change", "the total
   time spent in each state", "the number of transitions to each state",
   etc.  Some of these requirements are fulfilled explicitly by MIB
   objects such as eoPowerOperState, eoPowerStateTotalTime, and
   eoPowerStateEnterCount.  Some of the other requirements are met via
   the SNMP NOTIFICATION mechanism.  eoPowerStateChange SNMP
   notification which is generated when the value of oPowerStateIndex,
   eoPowerOperState, or eoPowerAdminState have changed.



(page 18 continued on part 2)

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