RFC 7460
Monitoring and Control MIB for Power and Energy
Pages: 69
Proposed Standard
Proposed Standard
Part 1 of 4 – Pages 1 to 18
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 EnergyAbstract
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.
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
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].
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
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.
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)
|
+---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.
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)
| +-- 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 |
| +---------------------------+
| +---------------------------------+ |---- |_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
+-----------------------+ |---> | 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
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.
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".
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,
(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
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
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
(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.
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