| Network Working Group | J. Quittek, Ed. |
| Internet-Draft | R. Winter |
| Intended status: Informational | T. Dietz |
| Expires: August 31, 2012 | NEC Europe Ltd. |
| B. Claise | |
| M. Chandramouli | |
| Cisco Systems, Inc. | |
| March 2012 |
Requirements for Energy Management
draft-ietf-eman-requirements-06
This document defines requirements for standards specifications for energy management. The requirements defined in this document concern monitoring functions as well as control functions. In detail, the focus of the requirements is on the following features: identification of powered entities, monitoring of their power state, power inlets, power outlets, actual power, power properties, consumed energy, and contained batteries. Further requirements are included to enable control of powered entities' power supply and power state. This document does not specify the features that must be implemented by compliant implementations but rather features that must be supported by standards for energy management.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 31, 2012.
Copyright (c) 2012 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.
With rising energy cost and with an increasing awareness of the ecological impact of running IT equipment, energy management is becoming an additional basic requirement for network devices and associated network management systems.
This document defines requirements for standards specifications for energy management, both monitoring functions and control functions. In detail, the requirements listed are focused on the following features: identification of powered entities, monitoring of their power state, power inlets, power outlets, actual power, power properties, consumed energy, and contained batteries. Further included is control of powered entities' power supply and power state.
The main subject of energy management is powered entities that consume electric energy. Powered entities include devices that have an IP address and can be addressed directly, such as hosts, routers, and middleboxes, as well as devices indirectly connected to an IP network, for which a proxy with an IP address provides a management interface, for example, devices in building infrastructure using non-IP protocols.
These requirements concern the standards specification process and not the implementation of specified standards. All requirements in this document must be reflected by standards specifications to be developed. However, which of the features specified by these standards will be mandatory, recommended, or optional for compliant implementations is to be defined by standards track document(s) and not in this document.
Section 3 elaborates a set of general needs for energy management. Requirements for an energy management standard are specified in Sections 4 to 8.
Sections 4 to 6 contain conventional requirements specifying information on powered entities and control functions.
Sections 7 and 8 contain requirements specific to energy management. Due to the nature of power supply, some monitoring and control functions are not conducted by interacting with the powered entity of interest, but with other entities, for example, entities upstream in a power distribution tree.
The specification of requirements for an energy management standard starts with Section 4 addressing the identification of powered entities and the granularity of reporting of energy-related information. A standard must support unique identification of powered entities, reporting per entire powered device, and reporting energy-related information on individual components of a device or subtended devices. This is why this draft uses the more general term "powered entity" rather than "powered device"; a powered entity may be a device or a component of a device.
Section 5 specifies requirements related to monitoring of powered entities. This includes general (type, context) information and specific information on power states, power inlets, power outlets, power, energy, and batteries. Control power state and power supply of powered entities is covered by requirements specified in Section 6.
While the conventional requirements summarized above seem to be all that would be needed for energy management, there are significant differences between energy management and most well known network management functions. The most significant difference is the need for some devices to report on other entities. There are three major reasons for this.
This specific issue of energy management and a set of further ones are covered by requirements specified in Sections 7 and 8.
The requirements in these sections need a new energy management framework that deals with the specific nature of energy management. The actual standards documents, such as MIB module specifications, address conformance by specifying which feature must, should, or may to be implemented by compliant implementations.
Terminology to be used by the eman WG is currently discussed in [I-D.parello-eman-definitions]. After final definitions of terms have been agreed, those definitions will be listed here.
The basic objective of energy management is operating sets of devices with minimal energy, while maintaining a certain level of service. Use cases for energy management can be found in [I-D.ietf-eman-applicability-statement].
Powered entities can be set to an operational state that results in the lowest energy consumption level that still meets the service level performance objectives. In principle, there are four basic types of power states for a powered entity or for a whole system:
In specific devices, the number of power states and their properties varies considerably. Simple powered entities may just have only the extreme states, full power and off state. Many devices have three basic power states: on, off, and sleep. However, more finely grained power states can be implemented with many levels of each power states.
While the general objective of energy management is quite clear, the way to attain that goal is often difficult. In many cases there is no way of reducing power consumption without the consequence of a potential performance, service, or capacity degradation. Then a trade-off needs to be dealt with between service level objectives and energy minimization. In other cases a reduction of energy consumption can easily be achieved while still maintaining sufficient service level performance, for example, by switching powered entities to lower power states when higher performance is not needed.
Many energy saving functions are executed locally by a powered entity; it monitors its usage and dynamically adapts its energy consumption according to the required performance. It may, for example, switch to a sleep state when it is not in use or out of scheduled business hours. An energy management system may observe an entity's power state and configure its power saving policies.
Energy savings can also be achieved with policies implemented by a network management system that controls power states of managed entities. Information about the energy consumption of powered entities in different power states may be required to set policy. Often this information is acquired best through monitoring.
Both methods, network-wide and local energy management, have advantages and disadvantages and often it is desirable to combine them. Central management is often favorable for setting power states of a large number of entities at the same time, for example, at the beginning and end of business hours in a building. Local management is often preferable for power saving measures based on local observations, such as high or low load of an entity.
Monitoring energy consumption and power states alone does not reduce the energy consumption of a powered entity. In fact, it may increase the power consumption slightly due to monitoring instrumentation that consumes energy. Reporting measured quantities over the network may also increase energy use, though the acquired information may be an essential input to control loops that save energy.
Monitoring power states and energy consumption can also be required for other purposes including:
The following basic management functions are required:
Power control is complementary to other energy savings measures such as low power electronics, energy saving protocols , energy-efficient device design (for example, low-power modes for components), and energy-efficient network architectures. Measurement of energy consumption can provide useful data for developing these technologies.
Powered entities must be uniquely identified. This includes entities that are components of managed devices and in case that one powered entity reports information on another one, see Section 7. For powered entities that control other powered entities it is important to identify the powered entities they control, see Section 8.
An entity may be an entire device or a component of it. Examples of components of interest are a hard drive, a battery, or a line card. It may be required to be able to control individual components to save energy. For example, server blades can be switched off when the overall load is low or line cards at switches may be powered down at night.
Identifiers for devices and components are already defined in standard MIB modules, such as the LLDP MIB module [IEEE-802.1AB] and the LLDP-MED MIB module [ANSI-TIA-1057] for devices and the Entity MIB module [RFC4133] and the Power Ethernet MIB [RFC3621] for components of devices. Energy management needs means to link energy-related information to such identifiers.
Instrumentation for measuring energy consumption of a device is typically more expensive than instrumentation for retrieving its power state. Many devices may provide power state information for all individual components separately, while reporting the energy consumption only for the entire device.
The standard must provide means for uniquely identifying powered entities. Uniqueness must be preserved in a domain that is large enough to avoid collisions of identities at potential receivers of monitored information.
The standard must provide means for identifying not just entire devices as powered entities, but also individual components.
The standard must provide means for indicating whether identifiers of powered entities are persistent across a re-start of the powered entity.
The standard must provide means for re-using entity identifiers from other standards including at least the following:
Generic means for re-using other entity identifiers must be provided.
This section describes information on powered entities for which the standard must provide means for retrieving and reporting.
Required information can be structured into six groups. Section 5.1 specifies requirements for general information on powered entities, such as type of powered entity or context information. Section 5.4 covers requirements related to entities' power states. Requirements for information on power inlets and power outlets of powered entities are specified in Section 5.2. Monitoring of power and energy is covered by Sections 5.3 and 5.5, respectively. Section 5.6 specifies requirements for monitoring batteries. Finally, the reporting of time series of values is covered by Section 5.7.
For energy management it may be required to understand the role and context of a powered entity. An energy management system may aggregate energy consumption according to a defined grouping of entities. When controlling and setting power states it may be helpful to understand the grouping of the entity and role of a powered entity in a network, for example, it may be important to exclude some vital network devices from being switched to lower power or even from being switched off.
The standard must provide means to configure, retrieve and report a textual name or a description of a powered entity.
The standard must provide means for retrieving and reporting context information on powered entities, for example, tags associated with a powered entity that indicate the powered entity's role or importance.
The standard must provide means for retrieving and reporting power priorities of powered entities. Power priorities indicate an order in which power states of powered entities are changed, for example, to lower power states for saving power.
The standard must provide means for grouping powered entities, for example, into energy monitoring domains, energy control domains, power supply domains, groups of powered entities of the same type, etc.
A power interface is either an inlet or an outlet. A few switch between these two but most never change.
Powered entities have power inlets at which they are supplied with electric power. Most powered entities have a single power inlet, while some have multiple inlets. Different power inlets on a device are often connected to separate power distribution trees. For energy monitoring, it is useful to retrieve information on the number of inlets of a powered entity, the availability of power at inlets and which of them are actually in use.
Powered entities can have one or more power outlets for supplying other powered entities with electric power.
For identifying and potentially controlling the source of power received at an inlet, it may be required to identify the power outlet of another powered entity at which the received power is provided. Analogously, for each outlet it is of interest to identify the power inlets that receive the power provided at a certain outlet. Such information is also required for constructing the wiring topology of electrical power distribution to powered entities.
Static properties of each power interface are required information for energy management. Static properties include the kind of electric current (AC or DC), the nominal voltage, the nominal AC frequency, and the number of AC phases.
The standard must provide means for monitoring the list of power interfaces.
The standard must provide means for identifying the power outlet that provides the power received at a power inlet.
The standard must provide means for identifying the list of power inlets that receive the power provided at a power outlet.
The standard must provide means for monitoring the availability of power at each power interface. This indicates whether at a power interfaces power supply is switched on or off.
The standard must provide means for monitoring for each power interfaces if it is in actual use. For inlets this means that the powered entity actually receives power at the inlet. For outlets this means that power is actually provided from it to one or more powered entities.
The standard must provide means for reporting the type of current (AC or DC) for each power interface.
The standard must provide means for reporting the nominal voltage for each power interface.
The standard must provide means for reporting the nominal AC frequency for each power interface.
The standard must provide means for reporting the number of AC phases for each power interface.
Power is measured as an instantaneous value or as the average over a time interval.
Obtaining highly accurate values for power and energy may be costly if it requires dedicated metering hardware. Powered entities without the ability to measure their power and energy consumption with high accuracy may just report estimated values, for example based on load monitoring or even just the entity type.
Depending on how power and energy consumption values are obtained, the confidence in the reported value and its accuracy will vary. Powered entities reporting such values should qualify the confidence in the reported values and quantify the accuracy of measurements. For reporting accuracy, the accuracy classes specified in IEC 62053-21 [IEC.62053-21] and IEC 62053-22 [IEC.62053-22] should be considered.
Further properties of the supplied power are also of interest. For AC power supply, power attributes beyond the real power to be reported include the apparent power, the reactive power, and the phase angle of the current or the power factor. For both AC and DC power the power characteristics are also subject of monitoring. Power parameters include the actual voltage, the actual frequency, the Total Harmonic Distortion (THD) of voltage and current, the impedance of an AC phase or of the DC supply. Power monitoring should be in line with existing standards, such as [IEC.61850-7-4].
For some network management tasks it is desirable to receive notifications from powered entities when their power value exceeds or falls below given thresholds.
The standard must provide means for reporting the real power for each power interface, including the direction of power flow.
The standard must provide means for reporting the corresponding time or time interval for which a power value is reported. The power value can be measured at the corresponding time or averaged over the corresponding time interval.
The standard must provide means to indicating the method how these values have been obtained. Based on how the measurement was obtained, it is possible to associate a certain degree of confidence on the reported power value. For example, there are methods of measurement such as direct power measurement, or by estimation based on performance values, or hard coding average power values for a powered entity.
The standard must provide means for reporting the accuracy of reported power and energy values.
The standard must provide means for reporting the actual voltage and actual current for each power interface. In case of AC power supply, means must be provided for reporting the actual voltage and actual current per phase.
The standard must provide means for creating notifications if power values of a powered entity rise above or fall below given thresholds.
The standard must provide means for reporting the complex power for each power interface. Besides the real power, at least two out of the following three quantities need to be reported: apparent power, reactive power, phase angle. The phase angle can be substituted by the power factor. In case of AC power supply, means must be provided for reporting the complex power per phase.
The standard must provide means for reporting the actual AC frequency for each power interface.
The standard must provide means for reporting the Total Harmonic Distortion (THD) of voltage and current for each power interface. In case of AC power supply, means must be provided for reporting the THD per phase.
The standard must provide means for reporting the impedance of power supply for each power interface. In case of AC power supply, means must be provided for reporting the impedance per phase.
Many powered entities have a limited number of discrete power states.
There is a need to report the actual power state of a powered entity, and means for retrieving the list of all supported power states.
Different standards bodies have already defined sets of power states for some powered entities, and others are creating new power state sets. In this context, it is desirable that the standard support many of these power state standards. In order to support multiple management systems possibly using different power state sets, while simultaneously interfacing with a particular powered entity, the energy management standard must provide means for supporting multiple power state sets used simultaneously at a powered entity.
Power states have parameters that describe its properties. It is required to have standardized means for reporting some key properties, such as average power and maximum power of a powered entity in a certain state.
There also is a need to report statistics on power states including the time spent and the energy consumed in a power state.
The standard must provide means for reporting the actual power state of a powered entity.
The standard must provide means for retrieving the list of all potential power states of a powered entity.
The standard must provide means for supporting multiple power state sets simultaneously at a powered entity.
The standard must provide means for retrieving the list of all power state sets supported by a powered entity.
The standard must provide means for retrieving the list of all potential power states of a powered entity for each supported power state set.
The standard must provide means for retrieving the maximum power and the average power for each supported power state. These values may be static.
The standard must provide means for monitoring statistics per power state including the total time spent in a power state, the number of times each state was entered and the last time each state was entered. More power state statistics are addressed by requirement 5.5.3.
The standard must provide means for generating a notification when the actual power state of a powered entity changes.
Monitoring of electrical energy received or provided by a powered entity is a core function of energy management. Since energy is an accumulated quantity, it is always reported for a certain interval of time. This can be, for example, the time from the last restart of the powered entity to the reporting time, the time from another past event to the reporting time, the last given amount of time before the reporting time, or a certain interval specified by two time stamps in the past.
It is useful for powered entities to record their energy consumption per power state and report these quantities.
The standard must provide means for reporting the energy consumed or produced of a powered entity. The standard must also provide the means to report the energy passing through each power interface. Reports should clearly specify the time interval for the energy measurement.
The standard must provide means for reporting the consumed energy of a powered entity for specified time intervals.
The standard must provide means for reporting the consumed energy individually for each power state. This extends the requirement 5.4.7 on power state statistics.
Many powered entities contain batteries that supply them with power when disconnected from electrical power distribution grids. The status of these batteries is typically controlled by automatic functions that act locally on the powered entity and manually by users of the powered entity. There is a need to monitor the battery status of these entities by network management systems.
Devices containing batteries can be modeled in two ways. The entire device can be modeled as a single powered entity on which energy-related information is reported or the battery can be modeled as an individual powered entity for which energy-related information is monitored individually according to requirements in Sections 5.1 to 5.5.
Further information on batteries is of interest for energy management, such as the current charge of the battery, the number of completed charging cycles, the charging state of the battery, and further static and dynamic battery properties. It is desirable to receive notifications if the charge of a battery becomes very low or if a battery needs to be replaced.
The standard must provide means for reporting the current charge of a battery.
The standard must provide means for reporting the charging state (charging, discharging, etc.) of a battery.
The standard must provide means for reporting the number of completed charging cycles of a battery.
The standard must provide means for reporting the actual capacity of a battery.
The standard must provide means for reporting static properties of a battery, including the nominal capacity, the number of cells, the nominal voltage, and the battery technology.
The standard must provide means for generating a notification when the charge of a battery decreases below a given threshold.
The standard must provide means for generating a notification when the number of charging cycles of battery exceeds a given threshold.
The standard must provide means for meeting requirements 5.6.1 to 5.6.7 for each individual battery contained in a single powered entity.
For some network management tasks, it is required to obtain time series of measured values, such as power, energy, battery charge, etc.
In general these could be obtained in many different ways. It should be avoided that such time series can only be obtained through regular polling by the energy management system. Means should be provided to either push such values from the location where they are available to the management system or to have them stored locally for a sufficiently long period of time such that a management system can retrieve full time series.
While there is a common understanding that support for reporting of time series is needed, there is no clear agreement on four issues:
The most discussed and probably most needed quantities are power and energy. But a need for others, for example, battery charge can be identified as well.
There are three time interval types under discussion for accumulated quantities such as energy. They can be reported as total values, accumulated between the last restart of the measurement and a certain timestamp. Alternatively, they can be reported as delta values between two consecutive timestamps. Another alternative is reporting values for sliding windows as specified in [IEC.61850-7-4].
For non-accumulative quantities, such as power, different measurement methods are considered. Such quantities can be reported using values sampled at certain time stamps or alternatively by mean values for these quantities averaged between two (consecutive) time stamps or over a sliding window.
Finally, time series can be reported using different reporting models, particularly push-based or pull-based. Push-based reporting can, for example, be realized by reporting power or energy values using the IPFIX protocol [RFC5101],[RFC5102]. SNMP [RFC3411] is an example for a protocol that can be used for realizing pull-based reporting of time series.
All these issues are not clear at the time this document is written. If practical experiences with the energy management standard to be defined will be available, they may help reducing the large number of choices and identifying and specifying commonly shared requirements for reporting time series of energy-related quantities in a future revision of this document.
Many powered entities control their power state locally. Other powered entities without that capability need interfaces for an energy management system to control their power states. Even for self-managed powered entities such interfaces may be required for configuring local policy parameters and for overruling local policy decisions by global ones.
Power supply is typically not self-managed by powered entities. And controlling power supply is typically not conducted as interaction between energy management system and the powered entity itself. It is rather an interaction between the management system and an entity providing power at its power outlets. Similar to power state control, power supply control may be policy driven. Note that shutting down the power supply abruptly may have severe consequences for the powered entity.
The standard must provide means for setting power states of powered entities.
The standard must provide means for switching power supply off or turning power supply on at power outlets providing power to one or more powered entity.
As discussed in Section 5, not all energy-related information may be available at the concerned powered entity. Such information may be provided by other powered entities. This section covers reporting of information only. See Section 8 for requirements on controlling other powered entities.
There are cases where a power supply unit switches power for several powered entities by turning power on or off at a single power outlet or where a power meter measures the accumulated power of several powered entities at a single power line. Consequently, it should be possible to report that a monitored value does not relate to just a single powered entity, but is an accumulated value for a set of powered entities. All of these powered entities belonging to that set need to be identified.
If a powered entity has information about where energy-related information on itself can be retrieved, then it would be useful to communicate this information. This applies even if the information only provides accumulated quantities for several powered entities.
The standard must provide means for a powered entity to report information on another powered entity.
For entities that report on one or more other entities, the standard must provide means for reporting the identity of other powered entities on which information is reported.
The standard must provide means for reporting the list of all powered entities from which contributions are included in an accumulated value.
For entities that report on one or more other entities, the standard must provide means for reporting the complete list of all those powered entities on which energy-related information can be reported.
For entities that report on one or more other entities, the standard must provide means for indicating which energy-related information can be reported for which of those powered entities.
For an entity that has one or more other entities reporting on its behalf, the standard must provide means for the entity to to indicate which information is available at which other entity.
For an entity that has one or more other entities reporting on its behalf, the standard must provide means for indicating the content that other designated entities can report on it.
This section specifies requirements for controlling power states and power supply of powered entities by communicating with other powered entities that have means for controlling power state or power supply of others.
Some powered entities have control of power states of other powered entities. For example a gateway to a building system may have means to control the power state of powered entities in the building that do not have an IP interface. For this scenario and other similar cases means are needed to make this control accessible to the energy management system.
In addition to this, it is required that a powered entity that has its state controlled by other powered entities has means to report the list of these other powered entities.
The standard must provide means for an energy management system to send power state control commands to a powered entity that concern the power states of other powered entities than the one the command was sent to.
The standard must provide means for reporting the identities of the powered entities for which reporting powered entity has means to control their power states.
The standard must provide means for a powered entity to report the list of all powered entities for which it can control the power state.
The standard must provide means for a powered entity that receives commands controlling its power state from other powered entities to report the list of all those entities.
Some powered entities may have control of the power supply of other powered entities, for example, because the other powered entity is supplied via a power outlet of the powered entity. For this and similar cases means are needed to make this control accessible to the energy management system. This need is already addressed by requirement 6.2.
In addition, it is required that a powered entity that has its supply controlled by other powered entities has means to report the list of these other powered entities. This need is already addressed by requirements 5.2.2 and 5.2.3.
Controlling power state and power supply of powered entities are highly sensitive actions since they can significantly affect the operation of directly and indirectly affected devices. Therefore all control actions addressed in 6 and 8 must be sufficiently protected through authentication, authorization, and integrity protection mechanisms.
Monitoring energy-related quantities of a powered entity addressed in Sections 5 - 8 can be used to derive more information than just the consumed power, so monitored data requires privacy protection. Monitored data may be used as input to control, accounting, and other actions, so integrity of transmitted information and authentication of the origin may be needed.
The standard must provide privacy, integrity, and authentication mechanisms for all actions addressed in Sections 5 - 8. The security mechanisms must address all threats listed in Section 1.4 of [RFC3411].
This document has no actions for IANA.
The authors would like to thank Ralf Wolter for his first essay on this draft. Many thanks to William Mielke, John Parello, Bruce Nordman, JinHyeock Choi, Georgios Karagiannis, and Michael Suchoff for helpful comments on the draft.
Is there a standard on DC power characteristics? Would they be needed for EMAN?
Still not covered consistently.
YCM === I am not certain we need this requirement. I understand the point a requirement need not be implemented. My contention impedance and THD are not necessary for EMAN.
After the requirements on time series have been dropped, requirement 5.5.2 on time intervals for energy measurements may have to be revised.
This needs to be considered whether it is devices or interfaces or entities that are to be reported on.
This section analyzes existing standards for energy consumption and power state monitoring. It shows that there are already several standards that cover only some part of the requirements listed above, but even all together they do not cover all of the requirements for energy management.
There are already RFCs available that address a subset of the requirements.
The ENTITY-MIB module defined in [RFC4133] was designed to model physical and logical entities of a managed system. A physical entity is an identifiable physical component. A logical entity can use one or more physical entities. From an energy monitoring perspective of a managed system, the ENTITY-MIB modeling framework can be reused and whenever RFC 4133 [RFC4133] has been implemented. The entPhysicalIndex from entPhysicalTable can be used to identify an entity/component. However, there are use cases of energy monitoring, where the application of the ENTITY-MIB does not seem readily apparent and some of those entities could be beyond the original scope and intent of the ENTITY-MIB.
Consider the case of remote devices attached to the network, and the network device could collect the energy measurement and report on behalf of such attached devices. Some of the remote devices such as PoE phones attached to a switch port have been considered in the Power-over-Ethernet MIB module [RFC3621]. However, there are many other devices such as a computer, which draw power from a wall outlet or building HVAC devices which seem to be beyond the original scope of the ENTITY-MIB.
Yet another example, is smart-PDUs, which can report the energy consumption of the device attached to the power outlet of the PDU. In some cases, the device can be attached to multiple to power outlets. Thus, the energy measured at multiple outlets need to be aggregated to determine the consumption of a single device. From mapping perspective, between the PDU outlets and the device this is a many-to-one mapping. It is not clear if such a many-to-one mapping is feasible within the ENTITY-MIB framework.
RFC 4268 [RFC4268] defines the ENTITY STATE MIB module. Implementations of this module provide information on entities including the standby status (hotStandby, coldStandby, providingService), the operational status (disabled, enabled, testing), the alarm status (underRepair, critical, major, minor, warning), and the usage status (idle, active, busy). This information is already useful as input for policy decisions and for other network management tasks. However, the number of states would cover only a small subset of the requirements for power state monitoring and it does not provide means for energy consumption monitoring. For associating the information conveyed by the ENTITY STATE MIB to specific components of a device, the ENTITY STATE MIB module makes use of the means provided by the ENTITY MIB module [RFC4133]. Particularly, it uses the entPhysicalIndex for identifying entities.
The standby status provided by the ENTITY STATE MIB module is related to power states required for energy management, but the number of states is too restricted for meeting all energy management requirements. For energy management several more power states are required, such as different sleep and operational states as defined by the Advanced Configuration and Power Interface (ACPI) [ACPI.R30b] or the DMTF Power State Management Profile [DMTF.DSP1027].
RFC 3433 [RFC3433] defines the ENTITY SENSOR MIB module. Implementations of this module offer a generic way to provide data collected by a sensor. A sensor could be an energy consumption meter delivering measured values in Watt. This could be used for reporting current power of an entity and its components. Furthermore, the ENTITY SENSOR MIB can be used to retrieve the accuracy of the used power meter.
Similar to the ENTITY STATE MIB module, the ENTITY SENSOR MIB module makes use of the means provided by the ENTITY MIB module [RFC4133] for relating provided information to components of a device.
However, there is no unit available for reporting energy quantities, such as, for example, watt seconds or kilowatt hours, and the ENTITY SENSOR MIB module does not support reporting accuracy of measurements according to the IEC / ANSI accuracy classes, which are commonly in use for electric power and energy measurements. The ENTITY SENSOR MIB modules only provides a coarse-grained method for indicating accuracy by stating the number of correct digits of fixed point values.
RFC 1628 [RFC1628] defines the UPS MIB module. Implementations of this module provide information on the current real power of entities attached to an uninterruptible power supply (UPS) device. This application would require identifying which entity is attached to which port of the UPS device.
UPS MIB provides information on the state of the UPS network. The MIB module contains several variables that are used to identify the UPS entity (name, model,..), the battery state, to characterize the input load to the UPS, to characterize the output from the UPS, to indicate the various alarm events. The measurements of power in UPS MIB are in Volts, Amperes and Watts. The units of power measurement are RMS volts, RMS Amperes and are not based on Entity-Sensor MIB [RFC3433].
Similar to the UPS MIB, implementations of the POWER ETHERNET MIB module defined in RFC3621 [RFC3621] provide information on the current energy consumption of the entities that receive Power over Ethernet (PoE). This information can be retrieved at the power sourcing equipment. Analogous to the UPS MIB, it is required to identify which entities are attached to which port of the power sourcing equipment.
The POWER ETHERNET MIB does not report power and energy consumption on a per port basis, but can report aggregated values for groups of ports. It does not use objects of the ENTITY MIB module for identifying entities, although this module existed already when the POWER ETHERNET MIB modules was standardized.
The Link Layer Discovery Protocol (LLDP) defined in IEEE 802.1ab is a data link layer protocol used by network devices for advertising of their identities, capabilities, and interconnections on a LAN network. The Media Endpoint Discovery (MED) (ANSI-TIA-1057) is an enhancement of LLDP known as LLDP-MED. The LLDP-MED enhancements specifically address voice applications. LLDP-MED covers 6 basic areas: capabilities discovery, LAN speed and duplex discovery, network policy discovery, location identification discovery, inventory discovery, and power discovery.
The DMTF has defined a power state management profile [DMTF.DSP1027] that is targeted at computer systems. It is based on the DMTF's Common Information Model (CIM) and it is rather an entity profile than an actual energy consumption monitoring standard.
The power state management profile is used to describe and to manage the power state of computer systems. This includes e.g. means to change the power state of an entity (e.g. to shutdown the entity) which is an aspect of but not sufficient for active energy management.
ODVA is an association consisting of members from industrial automation companies. ODVA supports standardization of network technologies based on the Common Industrial Protocol (CIP). Within ODVA, there is a special interest group focused on energy and standardization and inter-operability of energy aware entities.
The charter of the IEEE-ISTO Printer Working Group is for open standards that define printer related protocols, that printer manufacturers and related software vendors shall benefit from the interoperability provided by conformance to these standards. One particular aspect the Printer WG is focused on is power monitoring and management of network printers and imaging systems PWG Power Management Model for Imaging Systems [IEEE-ISTO]. Clearly, these devices are within the scope of energy management since these devices consume power and are attached to the network. In addition, there is ample scope of power management since printers and imaging systems are not used that often. IEEE-ISTO Printer working group has defined MIB modules for monitoring the power consumption and power state series that can be useful for power management of printers. The energy management framework should also take into account the standards defined in the Printer working group. In terms of other standards, IETF Printer MIB RFC3805 [RFC3805] has been standardized, however, this MIB module does not address power management of printers.