Energy Management Working Group Brad Schoening
Internet Draft Independent Consultant
Intended status: Informational Mouli Chandramouli
Expires: November 12, 2015 Cisco Systems Inc.
Bruce Nordman
Lawrence Berkeley National Laboratory
May 12, 2015
Energy Management (EMAN) Applicability Statement
draft-ietf-eman-applicability-statement-11
Abstract
The objective of Energy Management (EMAN) is to provide an
energy management framework for networked devices. This
document presents the applicability of the EMAN information
model in a variety of scenarios with cases and target devices.
These use cases are useful for identifying requirements for the
framework and MIBs. Further, we describe the relationship of
the EMAN framework to relevant other energy monitoring standards
and architectures.
Status of This Memo
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with the provisions of BCP 78 and BCP 79.
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Copyright Notice
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This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction ................................................. 3
1.1. Energy Management Overview ............................... 4
1.2. EMAN Document Overview ................................... 4
1.3. Energy Measurement ....................................... 5
1.4. Energy Management ........................................ 5
1.5. EMAN Framework Application ............................... 6
2. Scenarios and Target Devices ................................. 6
2.1. Network Infrastructure Energy Objects .................... 6
2.2. Devices Powered and Connected by a Network Device ........ 7
2.3. Devices Connected to a Network ........................... 8
2.4. Power Meters ............................................. 9
2.5. Mid-level Managers ...................................... 10
2.6. Non-residential Building System Gateways ................ 11
2.7. Home Energy Gateways .................................... 11
2.8. Data Center Devices ..................................... 12
2.9. Energy Storage Devices .................................. 13
2.10. Industrial Automation Networks ......................... 14
2.11. Printers ............................................... 14
2.12. Demand Response ........................................ 15
3. Use Case Patterns ........................................... 16
3.1. Metering ................................................ 16
3.2. Metering and Control .................................... 16
3.3. Power Supply, Metering and Control ...................... 16
3.4. Multiple Power Sources .................................. 16
4. Relationship of EMAN to Other Standards ..................... 16
4.1. Data Model and Reporting ................................ 17
4.1.1. IEC - CIM........................................ 17
4.1.2. DMTF............................................. 17
4.1.3. ODVA............................................. 18
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4.1.4. Ecma SDC......................................... 19
4.1.5. PWG.............................................. 19
4.1.6. ASHRAE........................................... 20
4.1.7. ANSI/CEA......................................... 21
4.1.8. ZigBee........................................... 21
4.2. Measurement ............................................. 22
4.2.1. ANSI C12......................................... 22
4.2.2. IEC 62301........................................ 22
4.3. Other ................................................... 22
4.3.1. ISO.............................................. 22
4.3.2. Energy Star...................................... 23
4.3.3. Smart Grid....................................... 24
5. Limitations ................................................. 24
6. Security Considerations ..................................... 25
7. IANA Considerations ......................................... 25
8. Acknowledgements ............................................ 25
9. References .................................................. 25
9.1. Normative References .................................... 25
9.2. Informative References .................................. 25
1. Introduction
The focus of the Energy Management (EMAN) framework is energy
monitoring and management of energy objects [RFC7326]. The
scope of devices considered are network equipment and their
components, and devices connected directly or indirectly to
the network. The EMAN framework enables monitoring of
heterogeneous devices to report their energy consumption and,
if permissible, control. There are multiple scenarios where
this is desirable, particularly considering the increased
importance of limiting consumption of finite energy resources
and reducing operational expenses.
The EMAN framework [RFC7326] describes how energy information
can be retrieved from IP-enabled devices using Simple Network
Management Protocol (SNMP), specifically, Management Information
Base (MIBs) for SNMP.
This document describes typical applications of the EMAN
framework, as well as its opportunities and limitations. It
also reviews other standards that are similar in part to EMAN
but address different domains, describing how those other
standards relate to the EMAN framework.
The rest of the document is organized as follows. Section 2
contains a list of use cases or network scenarios that EMAN
addresses. Section 3 contains an abstraction of the use case
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scenarios to distinct patterns. Section 4 deals with other
standards related and applicable to EMAN.
1.1. Energy Management Overview
EMAN addresses the electrical energy consumed by devices
connected to a network. A first step to increase the energy
efficiency in networks and the devices attached to the network
is to enable energy objects to report their energy usage over
time. The EMAN framework addresses this problem with an
information model for electrical equipment: energy object
identification, energy object context, power measurement, and
power characteristics.
The EMAN framework defines SNMP MIB modules based on the
information model. By implementing these SNMP MIB modules, an
energy object can report its energy consumption according to the
information model. Based on the information model, the MIB
drafts specify SNMP MIB modules, but it is equally possible to
use other mechanisms such as YANG module, NETCONF, etc.
In that context, it is important to distinguish energy objects
that can only report their own energy usage from devices that
can also collect and aggregate energy usage of other energy
objects.
1.2. EMAN Document Overview
The EMAN work consists of the following Standard Track and
Informational documents in the area of energy management.
Applicability Statement (this document)
Requirements [EMAN-REQ]: This document presents requirements
of energy management and the scope of the devices considered.
Framework [RFC7326]: This document defines a framework for
providing energy management for devices within or connected to
communication networks, and lists the definitions for the
common terms used in these documents.
Energy Object Context MIB [RFC761]: This document defines a MIB
module that characterizes a device's identity, context and
relationships to other entities.
Monitoring and Control MIB [RFC7460]: This document defines a MIB
module for monitoring the power and energy consumption of a device.
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The MIB module contains an optional module for metrics
metrics associated with power characteristics.
Battery MIB [EMAN-BATTERY-MIB]: This document defines a MIB
module for monitoring characteristics of an internal battery.
1.3. Energy Measurement
It is increasingly common for today's smart devices to measure
and report their own energy consumption. Intelligent power
strips and some Power over Ethernet (PoE) switches can meter
consumption of connected devices. However, when managed and
reported through proprietary means, this information is
difficult to view at the enterprise level.
The primary goal of the EMAN information model is to enable
reporting and management within a standard framework that is
applicable to a wide variety of end devices, meters, and
proxies. This enables a management system to know who's
consuming what, when, and how by leveraging existing networks,
across various equipment, in a unified and consistent manner.
Because energy objects may both consume energy and provide
energy to other devices, there are three types of energy
measurement: energy input to a device, energy supplied to other
devices, and net (resultant) energy consumed (the difference
between energy input and supplied).
1.4. Energy Management
The EMAN framework provides mechanisms for energy control in
addition to passive monitoring. There are many cases where
active energy control of devices is desirable, such during low
device utilization or peak electrical price periods.
Energy control can be as simple as controlling on/off states. In
many cases, however, energy control requires understanding the
energy object context. For instance, in commercial building
during non-business hours, some phones must remain available in
case of emergency and office cooling is not usually turned off
completely, but the comfort level is reduced.
Energy object control therefore requires flexibility and support
for different polices and mechanisms: from centralized
management by an energy management system, to autonomous control
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by individual devices, and alignment with dynamic demand
response mechanisms.
The EMAN framework power states can be used in demand response
scenarios. In response to time-of-day fluctuation of energy
costs or grid power shortages, network devices can respond and
reduce their energy consumption.
1.5. EMAN Framework Application
A Network Management System (NMS) is an entity that requests
information from compatible devices, typically using the SNMP
protocol. An NMS may implement many network management
functions, such as security or identity management. An NMS that
deals exclusively with energy is called an Energy Management
System (EnMS). It may be limited to monitoring energy use, or
it may also implement control functions. An EnMS collects
energy information for devices in the network.
Energy management can be implemented by extending existing SNMP
support with EMAN specific MIBs. SNMP provides an industry-
proven and well-known mechanism to discover, secure, measure,
and control SNMP-enabled end devices. The EMAN framework
provides an information and data model to unify access to a
large range of devices.
2. Scenarios and Target Devices
This section presents energy management scenarios that the EMAN
framework should solve. Each scenario lists target devices for
which the energy management framework can be applied, how the
reported-on devices are powered, and how the reporting or
control is accomplished. While there is some overlap between
some of the use cases, the use cases illustrate network
scenarios that the EMAN framework supports.
2.1. Network Infrastructure Energy Objects
This scenario covers the key use case of network devices and
their components. For a device aware of one or more components,
our information model supports monitoring and control at the
component level. Typically, the chassis draws power from one or
more sources and feeds its internal components. It is highly
desirable to have monitoring available for individual
components, such as line cards, processors, disk drives and
peripherals such as USB devices.
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As an illustrative example, consider a switch with the following
grouping of sub-entities for which energy management could be
useful.
. Physical view: chassis (or stack), line cards, and service
modules of the switch.
. Component view: CPU, ASICs, fans, power supply, ports
(single port and port groups), storage, and memory.
The ENTITY-MIB [RFC6933] provides a containment model for
uniquely identifying the physical sub-components of network
devices. The containment information identifies whether one
Energy Object belongs to another Energy Object (e.g. a line-card
Energy Object contained in a chassis Energy Object). The
mapping table entPhysicalContainsTable has an index
entPhysicalChildIndex and the table entPhysicalTable has a MIB
object entPhysicalContainedIn which points to the containing
entity.
The essential properties of this use case are:
. Target devices: network devices such as routers and
switches as well as their components.
. How powered: typically by a Power Distribution Unit (PDU)
on a rack or from a wall outlet. The components of a
device are powered by the device chassis.
. Reporting: direct power measurement can be performed at a
device level. Components can report their power
consumption directly or the chassis/device can report on
behalf of some components.
2.2. Devices Powered and Connected by a Network Device
This scenario covers Power Sourcing Equipment (PSE) devices. A
PSE device (e.g. a PoE switch) provides power to a Powered
Device (PD) (e.g. a desktop phone) over a medium such as USB or
Ethernet [RFC3621]. For each port, the PSE can control the
power supply (switching it on and off) and usually meter actual
power provided. PDs obtain network connectivity as well as
power over a single connection so the PSE can determine which
device is associated with each port.
PoE ports on a switch are commonly connected to devices such as
IP phones, wireless access points, and IP cameras. The switch
needs power for its internal use and to supply power to PoE
ports. Monitoring the power consumption of the switch
(supplying device) and the power consumption of the PoE end-
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points (consuming devices) is a simple use case of this
scenario.
This scenario illustrates the relationships between entities.
The PoE IP phone is powered by the switch. If there are many IP
phones connected to the same switch, the power consumption of
all the IP phones can be aggregated by the switch.
The essential properties of this use case are:
. Target devices: Power over Ethernet devices such as IP
phones, wireless access points, and IP cameras.
. How powered: PoE devices are connected to the switch port
which supplies power to those devices.
. Reporting: PoE device power consumption is measured and
reported by the switch (PSE) which supplies power. In
addition, some edge devices can support the EMAN framework.
This use case can be divided into two subcases:
a) The end-point device supports the EMAN framework, in which
case this device is an EMAN Energy Object by itself, with
its own UUID. The device is responsible for its own power
reporting and control. See the related scenario "Devices
Connected to a Network" below.
b) The end-point device does not have EMAN capabilities, and
the power measurement may not be able to be performed
independently, and is therefore only performed by the
supplying device. This scenario is similar to the "Mid-
level Manager" below.
In subcase (a) note that two power usage reporting mechanisms
for the same device are available: one performed by the PD
itself and one performed by the PSE. Device specific
implementations will dictate which one to use.
2.3. Devices Connected to a Network
This use case covers the metering relationship between an energy
object and the parent energy object to which it is connected,
while receiving power from a different source.
An example is a PC which has a network connection to a switch,
but draws power from a wall outlet. In this case, the PC can
report power usage by itself, ideally through the EMAN
framework.
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The wall outlet to which the PC is plugged in can be unmetered
or metered, for example, by a Smart PDU.
a) If metered, the PC has a powered-by relationship to the Smart
PDU, and the Smart PDU acts as a "Mid-Level Manager".
b) If unmetered, or operating on batteries, the PC will report
its own energy usage as any other Energy Object to the switch,
and the switch may possibly provide aggregation.
These two cases are not mutually exclusive.
In terms of relationships between entities, the PC has a
powered-by relationship to the PDU and if the power consumption
of the PC is metered by the PDU, then there is a metered-by
relation between the PC and the PDU.
The essential properties of this use case are:
. Target devices: energy objects that have a network
connection, but receive power supply from another source.
. How powered: end-point devices (e.g. PCs) receive power
supply from the wall outlet (unmetered), a PDU (metered),
or can be powered autonomously (batteries).
. Reporting: devices can either measure and report the power
consumption directly via the EMAN framework, communicate it
to the network device (switch) and the switch can report
the device's power consumption via the EMAN framework, or
power can be reported by the PDU.
2.4. Power Meters
Some electrical devices are not equipped with instrumentation to
measure their own power and accumulated energy consumption.
External meters can be used to measure the power consumption of
such electrical devices as well as collections of devices.
Three types of external metering are relevant to EMAN: PDUs,
standalone meters, and utility meters. External meters can
measure consumption of a single device or a set of devices.
Power Distribution Units (PDUs) can have built-in meters for
each socket and can measure the power supplied to each device in
an equipment rack. PDUs typically have remote management
capabilities which can report and possibly control the power
supply of each outlet.
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Standalone meters can be placed anywhere in a power distribution
tree and may measure all or part of the total. Utility meters
monitor and report accumulated power consumption of the entire
building. There can be sub-meters to measure the power
consumption of a portion of the building.
The essential properties of this use case are:
. Target devices: PDUs and meters.
. How powered: from traditional mains power but supplied
through a PDU or meter.
. Reporting: PDUs report power consumption of downstream
devices, usually a single device per outlet. Meters may
report for one or more devices and may require knowledge of
the topology to associate meters with metered devices.
Meters have metered-by relationships with devices, and may have
aggregation relationship between the meters and the devices for
which power consumption is accumulated and reported by the
meter.
2.5. Mid-level Managers
This use case covers aggregation of energy management data at
"mid-level managers" that can provide energy management
functions for themselves and associated devices.
A switch can provide energy management functions for all devices
connected to its ports, whether or not these devices are powered
by the switch or whether the switch provides immediate network
connectivity to the devices. Such a switch is a mid-level
manager, offering aggregation of power consumption data for
other devices. Devices report their EMAN data to the switch and
the switch aggregates the data for further reporting.
The essential properties of this use case:
. Target devices: devices which can perform aggregation;
commonly a switch or a proxy.
. How powered: mid-level managers are commonly powered by a
PDU or from a wall outlet but can be powered by any method.
. Reporting: the mid-level manager aggregates the energy data
and reports that data to an EnMS or higher mid-level
manager.
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2.6. Non-residential Building System Gateways
This use case describes energy management of non-residential
buildings. Building Management Systems (BMS) have been in place
for many years using legacy protocols not based on IP. In these
buildings, a gateway can provide a proxy function between IP
networks and legacy building automation protocols. The gateway
provides an interface between the EMAN framework and relevant
building management protocols.
Due to the potential energy savings, energy management of
buildings has received significant attention. There are gateway
network elements to manage the multiple components of a building
energy management system such as Heating, Ventilation, and Air
Conditioning (HVAC), lighting, electrical, fire and emergency
systems, elevators, etc. The gateway device uses legacy
building protocols to communicate with those devices, collects
their energy usage, and reports the results.
The gateway performs protocol conversion and communicates via
RS-232/RS-485 interfaces, Ethernet interfaces, and protocols
specific to building management such as BACNET [ASHRAE], MODBUS
[MODBUS], or ZigBee [ZIGBEE].
The essential properties of this use case are:
. Target devices: building energy management devices - HVAC
systems, lighting, electrical, fire and emergency systems.
. How powered: any method.
. Reporting: the gateway collects energy consumption of non-
IP systems and communicates the data via the EMAN
framework.
2.7. Home Energy Gateways
This use case describes the scenario of energy management of a
home. The home energy gateway is another example of a proxy
that interfaces with electrical appliances and other devices in
a home. This gateway can monitor and manage electrical
equipment (e.g. refrigerator, heating/cooling, or washing
machine) using one of the many protocols that are being
developed for residential devices.
Beyond simply metering, it's possible to implement energy saving
policies based on time of day, occupancy, or energy pricing from
the utility grid. The EMAN information model can be applied to
energy management of a home.
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The essential properties of this use case are:
. Target devices: home energy gateway and smart meters in a
home.
. How powered: any method.
. Reporting: home energy gateway can collect power
consumption of device in a home and possibly report the
metering reading to the utility.
2.8. Data Center Devices
This use case describes energy management of a data center.
Energy efficiency of data centers has become a fundamental
challenge of data center operation, as data centers are big
energy consumers and have expensive infrastructure. The
equipment generates heat, and heat needs to be evacuated through
an HVAC system.
A typical data center network consists of a hierarchy of
electrical energy objects. At the bottom of the network
hierarchy are servers mounted on a rack; these are connected to
top-of-the-rack switches, which in turn are connected to
aggregation switches, and then to core switches. Power
consumption of all network elements, servers, and storage
devices in the data center should be measured. Energy
management can be implemented on different aggregation levels,
i.e., at the network level, Power Distribution Unit (PDU) level,
and/or server level.
Beyond the network devices, storage devices, and servers, data
centers contain UPSs to provide back-up power for the facility
in the event of a power outage. A UPS can provide backup power
for many devices in a data center for a finite period of time.
Energy monitoring of energy storage capacity is vital from a
data center network operations point of view. Presently, the
UPS MIB can be useful in monitoring the battery capacity, the
input load to the UPS, and the output load from the UPS.
Currently, there is no link between the UPS MIB and the ENTITY
MIB.
In addition to monitoring the power consumption of a data
center, additional power characteristics should be monitored.
Some of these are dynamic variations in the input power supply
from the grid referred to as power quality metrics. It can also
be useful to monitor how efficiently the devices utilize power.
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Nameplate capacity of the data center can be estimated from the
nameplate ratings (the worst case possible power draw) of IT
equipment at a site.
The essential properties of this use case are:
. Target devices: IT devices in a data center, such as
network equipment, servers, and storage devices, as well as
power and cooling infrastructure.
. How powered: any method, but commonly by one or more PDUs.
. Reporting: devices may report on their own behalf, or for
other connected devices as described in other use cases.
2.9. Energy Storage Devices
Energy storage devices can have two different roles: one type
whose primary function is to provide power to another device
(e.g. a UPS), and one type with a different primary function,
but having energy storage as a component (e.g. a notebook).
This use case covers both.
The energy storage can be a conventional battery, or any other
means to store electricity such as a hydrogen cell.
An internal battery can be a back-up or an alternative source of
power to mains power. As batteries have a finite capacity and
lifetime, means for reporting the actual charge, age, and state
of a battery are required. An internal battery can be viewed as
a component of a device and so be contained within the device
from an ENTITY-MIB perspective.
Battery systems are often used in remote locations such as
mobile telecom towers. For continuous operation, it is
important to monitor the remaining battery life and raise an
alarm when this falls below a threshold.
The essential properties of this use case are:
. Target devices: devices that have an internal battery or
external storage.
. How powered: from batteries or other storage devices.
. Reporting: the device reports on its power delivered and
state.
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2.10. Industrial Automation Networks
Energy consumption statistics in the industrial sector are
staggering. The industrial sector alone consumes about half of
the world's total delivered energy, and is a significant user of
electricity. Thus, the need for optimization of energy usage in
this sector is natural.
Industrial facilities consume energy in process loads and non-
process loads.
The essential properties of this use case are:
. Target devices: devices used in an industrial sector.
. How powered: any method.
. Reporting: the CIP protocol is commonly used for reporting
energy for these devices.
2.11. Printers
This use case describes the scenario of energy monitoring and
management of printers. Printers in this use case stand in for
all imaging equipment, including multi-function devices (MFDs),
scanners, fax machines, and mailing machines.
Energy use of printers has been a longstanding industry concern
and sophisticated power management is common. Printers often
use a variety of low-power modes, particularly for managing
energy-intensive thermo-mechanical components. Printers also
have long made extensive use of SNMP for end-user system
interaction and for management generally, with cross-vendor
management systems able to manage fleets of printers in
enterprises. Power consumption during active modes can vary
widely, with high peak usage levels.
Printers can expose detailed power state information, distinct
from operational state information, with some printers reporting
transition states between stable long-term states. Many also
support active setting of power states and policies such as
delay times, when inactivity automatically transitions the
device to a lower power mode. Other features include reporting
on components, counters for state transitions, typical power
levels by state, scheduling, and events/alarms.
Some large printers also have a "Digital Front End," which is a
computer that performs functions on behalf of the physical
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imaging system. These typically have their own presence on the
network and are sometimes separately powered.
There are some unique characteristics of printers from the point
of view energy management. While the printer is not in use,
there are timer-based low power states, which consume little
power. On the other hand, while the printer is printing or
copying, the cylinder is heated so that power consumption is
quite high but only for a short period of time. Given this work
load, periodic polling of power levels alone would not suffice.
The essential properties of this use case are:
. Target devices: all imaging equipment.
. How powered: typically AC from a wall outlet.
. Reporting: devices report for themselves.
2.12. Demand Response
The theme of demand response from a utility grid spans across
several use cases. In some situations, in response to time-of-
day fluctuation of energy costs or sudden energy shortages due
power outages, it may be important to respond and reduce the
energy consumption of the network.
From the EMAN use case perspective, the demand response scenario
can apply to a data center, building or home. Real-time energy
monitoring is usually a prerequisite, so that during a potential
energy shortfall the EnMS can provide an active response. The
EnMS could shut down selected devices that are considered lower
priority or uniformly reduce the power supplied to a class of
devices. For multi-site data centers it may be possible to
formulate policies such as follow-the-sun type of approach, by
scheduling the mobility of VMs across data centers in different
geographical locations.
The essential properties of this use case are:
. Target devices: any device.
. How powered: traditional mains AC power.
. Reporting: real-time.
. Control: demand response based upon policy or priority.
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3. Use Case Patterns
The use cases presented above can be abstracted to the following
broad patterns for energy objects.
3.1. Metering
- Energy objects which have capability for internal metering
- Energy objects which are metered by an external device
3.2. Metering and Control
- Energy objects that do not supply power, but can perform power
metering for other devices
- Energy objects that do not supply power, but can perform both
metering and control for other devices
3.3. Power Supply, Metering and Control
- Energy objects that supply power for other devices but do not
perform power metering for those devices
- Energy objects that supply power for other devices and also
perform power metering
- Energy objects that supply power for other devices and also
perform power metering and control for other devices
3.4. Multiple Power Sources
- Energy objects that have multiple power sources, with metering
and control performed by the same power source
- Energy objects that have multiple power sources supplying
power to the device with metering performed by one or more
sources and control performed by another source
4. Relationship of EMAN to Other Standards
The EMAN framework is tied to other standards and efforts that
address energy monitoring and control. EMAN leverages existing
standards when possible, and it helps enable adjacent
technologies such as Smart Grid.
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The standards most relevant and applicable to EMAN are listed
below with a brief description of their objectives, the current
state, and how that standard relates to EMAN.
4.1. Data Model and Reporting
4.1.1. IEC - CIM
The International Electrotechnical Commission (IEC) has
developed a broad set of standards for power management. Among
these, the most applicable to EMAN is IEC 61850, a standard for
the design of electric utility automation. The abstract data
model defined in 61850 is built upon and extends the Common
Information Model (CIM). The complete 61850 CIM model includes
over a hundred object classes and is widely used by utilities
worldwide.
This set of standards were originally conceived to automate
control of a substation (a facility which transfer electricity
from the transmission to the distribution system). However, the
extensive data model has been widely used in other domains,
including Energy Management Systems (EnMS).
IEC TC57 WG19 is an ongoing working group with the objective to
harmonize the CIM data model and 61850 standards.
Several concepts from IEC Standards have been reused in the EMAN
drafts. In particular, AC Power Quality measurements have been
reused from IEC 61850-7-4. The concept of Accuracy Classes for
measurement of power and energy has been adapted from ANSI
C12.20 and IEC standards 62053-21 and 62053-22.
4.1.2. DMTF
The Distributed Management Task Force (DMTF) has defined a Power
State Management profile [DMTF DSP1027] for managing computer
systems using the DMTF's Common Information Model (CIM). These
specifications provide physical, logical, and virtual system
management requirements for power-state control services. The
DMTF standard does not include energy monitoring.
The Power State Management profile is used to describe and
manage the Power State of computer systems. This includes
controlling the Power State of an entity for entering sleep
mode, awakening, and rebooting. The EMAN framework references
the DMTF Power Profile and Power State Set.
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4.1.2.1. Common Information Model Profiles
The DMTF uses CIM-based (Common Information Model) 'Profiles' to
represent and manage power utilization and configuration of
managed elements (note that this is not the 61850 CIM). Key
profiles for energy management are 'Power Supply' (DSP 1015),
'Power State' (DSP 1027), and 'Power Utilization Management'
(DSP 1085). These profiles define many features for the
monitoring and configuration of a Power Managed Element's static
and dynamic power saving modes, power allocation limits, and
power states.
Reduced power modes can be established as static or dynamic.
Static modes are fixed policies that limit power use or
utilization. Dynamic power saving modes rely upon internal
feedback to control power consumption.
Power states are eight named operational and non operational
levels. These are On, Sleep-Light, Sleep-Deep, Hibernate, Off-
Soft, and Off-Hard. Power change capabilities provide
immediate, timed interval, and graceful transitions between on,
off, and reset power states. Table 3 of the Power State Profile
defines the correspondence between the Advanced Configuration
and Power Interface [ACPI] and DMTF power state models, although
it is not necessary for a managed element to support ACPI.
Optionally, a TransitioningToPowerState property can represent
power state transitions in progress.
4.1.2.2. DASH
DMTF DASH [DASH] (Desktop And Mobile Architecture for System
Hardware) addresses managing heterogeneous desktop and mobile
systems (including power) via in-band and out-of-band
communications. DASH uses the DMTF's WS-Management web services
and CIM data model to manage and control resources such as
power, CPU, etc.
Both in-service and out-of-service systems can be managed with
the DASH specification in a fully secured remote environment.
Full power lifecycle management is possible using out-of-band
management.
4.1.3. ODVA
The Open DeviceNet Vendors Association (ODVA) is an association
for industrial automation companies that defines the Common
Industrial Protocol (CIP). Within ODVA, there is a special
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interest group focused on energy and standardization and inter-
operability of energy-aware devices.
The ODVA is developing an energy management framework for the
industrial sector. There are synergies and similar concepts
between the ODVA and EMAN approaches to energy monitoring and
management.
ODVA defines a three-part approach towards energy management:
awareness of energy usage, energy efficiently, and the exchange
of energy with a utility or others. Energy monitoring and
management promote efficient consumption and enable automating
actions that reduce energy consumption.
The foundation of the approach is the information and
communication model for entities. An entity is a network-
connected, energy-aware device that has the ability to either
measure or derive its energy usage based on its native
consumption or generation of energy, or report a nominal or
static energy value.
4.1.4. Ecma SDC
The Ecma International standard on Smart Data Centre [Ecma-SDC]
defines semantics for management of entities in a data center
such as servers, storage, and network equipment. It covers
energy as one of many functional resources or attributes of
systems for monitoring and control. It only defines messages
and properties, and does not reference any specific protocol.
Its goal is to enable interoperability of such protocols as
SNMP, BACNET, and HTTP by ensuring a common semantic model
across them. Four power states are defined, Off, Sleep, Idle,
and Active. The standard does not include actual energy or
power measurements.
When used with EMAN, the SDC standard will provide a thin
abstraction on top of the more detailed data model available in
EMAN.
4.1.5. PWG
The IEEE-ISTO Printer Working Group (PWG) defines open standards
for printer related protocols, for the benefit of printer
manufacturers and related software vendors. The Printer WG
covers power monitoring and management of network printers and
imaging systems in the PWG Power Management Model for Imaging
Systems [PWG5106.4]. Clearly, these devices are within the
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scope of energy management since they receive 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.
The IEEE-ISTO Printer Working Group (PWG) defines SNMP MIB
modules for printer management and in particular a "PWG Power
Management Model for Imaging Systems v1.0" [PWG5106.4] and a
companion SNMP binding in the "PWG Imaging System Power MIB
v1.0" [PWG5106.5]. This PWG model and MIB are harmonized with
the DMTF CIM Infrastructure [DMTF DSP0004] and DMTF CIM Power
State Management Profile [DMTF DSP1027] for power states and
alerts.
These MIB modules can be useful for monitoring the power and
Power State of printers. The EMAN framework takes into account
the standards defined in the Printer Working Group. The PWG may
harmonize its MIBs with those from EMAN. The PWG covers many
topics in greater detail than EMAN, including those specific to
imaging equipment. The PWG also provides for vendor-specific
extension states (beyond the standard DMTF CIM states).
The IETF Printer MIB RFC3805 [RFC3805] has been standardized,
but, this MIB module does not address power management.
4.1.6. ASHRAE
In the U.S., there is an extensive effort to coordinate and
develop standards related to the "Smart Grid". The Smart Grid
Interoperability Panel, coordinated by the government's National
Institute of Standards and Technology, identified the need for a
building side information model (as a counterpart to utility
models) and specified this in Priority Action Plan (PAP) 17.
This was designated to be a joint effort by the American Society
of Heating, Refrigerating and Air-Conditioning Engineers
(ASHRAE) and the National Electrical Manufacturers Association
(NEMA), both ANSI approved SDO's. The result is to be an
information model, not a protocol.
The ASHRAE effort addresses data used only within a building as
well as data that may be shared with the grid, particularly as
it relates to coordinating future demand levels with the needs
of the grid. The model is intended to be applied to any
building type, both residential and commercial. It is expected
that existing protocols will be adapted to comply with the new
information model, as would new protocols.
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There are four basic types of entities in the model: generators,
loads, meters, and energy managers. The metering part of the
model overlaps to a large degree with the EMAN framework, though
there are features unique to each. The load part speaks to
control capabilities well beyond what EMAN covers. Details of
generation and of the energy management function are outside of
EMAN scope.
A public review draft of the ASHRAE standard was released in
July, 2012. There are no apparent major conflicts between the
two approaches, but there are areas where some harmonization is
possible.
4.1.7. ANSI/CEA
The Consumer Electronics Association (CEA) has approved
ANSI/CEA-2047 [ANSICEA] as a standard data model for Energy
Usage Information. The primary purpose is to enable home
appliances and electronics to communicate energy usage
information over a wide range of technologies with pluggable
modules that contain the physical layer electronics. The
standard can be used by devices operating on any home network
including Wi-Fi, Ethernet, ZigBee, Z-Wave, and Bluetooth. The
Introduction to ANSI/CEA-2047 states that "this standard
provides an information model for other groups to develop
implementations specific to their network, protocol and
needs". It covers device identification, current power level,
cumulative energy consumption, and provides for reporting time-
series data.
4.1.8. ZigBee
The ZigBee Smart Energy Profile 2.0 (SEP) effort [ZIGBEE]
focuses on IP-based wireless communication to appliances and
lighting. It is intended to enable internal building energy
management and provide for bi-directional communication with the
power grid.
ZigBee protocols are intended for use in embedded applications
with low data rates and low power consumption. ZigBee defines a
general-purpose, inexpensive, self-organizing mesh network that
can be used for industrial control, embedded sensing, medical
data collection, smoke and intruder warning, building
automation, home automation, etc.
ZigBee is currently not an ANSI recognized SDO.
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The EMAN framework addresses the needs of IP-enabled networks
through the usage of SNMP, while ZigBee provides for completely
integrated and inexpensive mesh solutions.
4.2. Measurement
4.2.1. ANSI C12
The American National Standards Institute (ANSI) has defined a
collection of power meter standards under ANSI C12. The primary
standards include communication protocols (C12.18, 21 and 22),
data and schema definitions (C12.19), and measurement accuracy
(C12.20). European equivalent standards are provided by IEC
62053-22
These very specific standards are oriented to the meter itself,
and are used by electricity distributors and producers.
The EMAN standard references ANSI C12.20 accuracy classes.
4.2.2. IEC 62301
IEC 62301, "Household electrical appliances Measurement of
standby power", [IEC62301] specifies a power level measurement
procedure. While nominally for appliances and low-power modes,
its concepts apply to other device types and modes and it is
commonly referenced in test procedures for energy using
products.
While the standard is intended for laboratory measurements of
devices in controlled conditions, aspects of it are informative
to those implementing measurement in products that ultimately
report via EMAN.
4.3. Other
4.3.1. ISO
The International Organization for Standardization (ISO) [ISO]
is developing an energy management standard, ISO 50001, to
complement ISO 9001 for quality management, and ISO 14001 for
environmental management. The intent is to facilitate the
creation of energy management programs for industrial,
commercial, and other entities. The standard defines a process
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for energy management at an organizational level. It does not
define the way in which devices report energy and consume
energy.
ISO 50001 is based on the common elements found in all of ISO's
management system standards, assuring a high level of
compatibility with ISO 9001 and ISO 14001. ISO 50001 benefits
include:
o Integrating energy efficiency into management practices and
throughout the supply chain.
o Energy management best practices and good energy management
behaviors.
o Benchmarking, measuring, documenting, and reporting energy
intensity improvements and their projected impact on
reductions in greenhouse gas (GHG) emissions.
o Evaluating and prioritizing the implementation of new energy-
efficient technologies.
ISO 50001 has been developed by ISO project committee ISO PC
242, Energy management. EMAN is complementary to ISO 9001.
4.3.2. Energy Star
The U.S. Environmental Protection Agency (EPA) and U.S.
Department of Energy (DOE) jointly sponsor the Energy Star
program [ESTAR]. The program promotes the development of energy
efficient products and practices.
To qualify as Energy Star, products must meet specific energy
efficiency targets. The Energy Star program also provides
planning tools and technical documentation to encourage more
energy efficient building design. Energy Star is a program; it
is not a protocol or standard.
For businesses and data centers, Energy Star offers technical
support to help companies establish energy conservation
practices. Energy Star provides best practices for measuring
current energy performance, goal setting, and tracking
improvement. The Energy Star tools offered include a rating
system for building performance and comparative benchmarks.
There is no immediate link between EMAN and Energy Star, one
being a protocol and the other a set of recommendations to
develop energy efficient products. However, Energy Star could
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include EMAN standards in specifications for future products,
either as required or rewarded with some benefit.
4.3.3. Smart Grid
The Smart Grid standards efforts underway in the United States
are overseen by the U.S. National Institute of Standards and
Technology [NIST]. NIST is responsible for coordinating a
public-private partnership with key energy and consumer
stakeholders in order to facilitate the development of Smart
Grid standards. These activities are monitored and facilitated
by the SGIP (Smart Grid Interoperability Panel). This group has
working groups for specific topics including homes, commercial
buildings, and industrial facilities as they relate to the grid.
A stated goal of the group is to harmonize any new standard with
the IEC CIM and IEC 61850.
When a working group detects a standard or technology gap, the
team seeks approval from the SGIP for the creation of a Priority
Action Plan (PAP), a private-public partnership to close the
gap. PAP 17 is discussed in section 4.1.6.
PAP 10 addresses "Standard Energy Usage Information". Smart
Grid standards will provide distributed intelligence in the
network and allow enhanced load shedding. For example, pricing
signals will enable selective shutdown of non-critical
activities during peak price periods. Actions can be effected
through both centralized and distributed management controls.
There is an obvious functional link between Smart Grid and EMAN
in the form of demand response, even though the EMAN framework
itself does not address any coordination with the grid. As EMAN
enables control, it can be used by an EnMS to accomplish demand
response through translation of a signal from an outside entity.
5. Limitations
EMAN addresses the needs of energy monitoring in terms of
measurement and considers limited control capabilities of energy
monitoring of networks.
EMAN does not create a new protocol stack, but rather defines a
data and information model useful for measuring and reporting
energy and other metrics over SNMP.
EMAN does not address questions regarding Smart Grid,
electricity producers, and distributors.
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6. Security Considerations
EMAN uses the SNMP protocol and thus has the functionality of
SNMP's security capabilities. SNMPv3 [RFC3411] provides
important security features such as confidentiality, integrity,
and authentication.
[RFC7460] section 10 and [RFC7461] section 6 mention that power
monitoring and management MIBs may have certain privacy
implications. These privacy implications are beyond the scope
of this document. There may be additional privacy
considerations specific to each use case; this document has not
attempted to analyze these.
7. IANA Considerations
This memo includes no request to IANA.
8. Acknowledgements
Firstly, the authors thank Emmanuel Tychon for taking the lead
for the initial draft and his substantial contributions to it.
The authors also thank Jeff Wheeler, Benoit Claise, Juergen
Quittek, Chris Verges, John Parello, and Matt Laherty for their
valuable contributions. The authors also thank Kerry Lynn for
the use case involving demand response.
9. References
9.1. Normative References
[RFC3411] An Architecture for Describing Simple Network
Management Protocol (SNMP) Management Frameworks, RFC
3411, December 2002.
[RFC3621] Power Ethernet MIB, RFC 3621, December 2003.
9.2. Informative References
[ACPI] "Advanced Configuration and Power Interface
Specification", http://www.acpi.info/spec30b.htm
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[DASH] "Desktop and mobile Architecture for System Hardware",
http://www.dmtf.org/standards/mgmt/dash/
[DMTF DSP0004] DMTF Common Information Model (CIM)
Infrastructure, DSP0004, May 2009.
http://www.dmtf.org/standards/published_documents/DSP00
04_2.5.0.pdf.
[DMTF DSP1027] DMTF Power State Management Profile, DSP1027,
December 2009.
http://www.dmtf.org/standards/published_documents/DSP10
27_2.0.0.pdf.
[Ecma-SDC] Ecma-400, "Smart Data Centre Resource Monitoring and
nd
Control (2 Edition)", June 2013.
[EMAN-REQ] Quittek, J., Chandramouli, M. Winter, R., Dietz, T.,
Claise, B., and Chandramouli, M. "Requirements for
Energy Management ", RFC 6988, September 2013.
[EMAN-MONITORING-MIB] Chandramouli, M., Schoening, B., Dietz,
T., Quittek, J. and Claise, B. "Energy and Power
Monitoring MIB ", draft-ietf-eman-monitoring-mib-13,
May 2015.
[EMAN-AWARE-MIB] Parello, J., Claise, B. and Chandramouli, M.
"draft-ietf-eman-energy-aware-mib-16", work in
progress, July 2014.
[RFC7326] Claise, B., Parello, J., Schoening, B., Quittek, J.
"Energy Management Framework", RFC7326, September 2014.
[EMAN-BATTERY-MIB] Quittek, J., Winter, R., and T. Dietz,
"Definition of Managed Objects for Battery Monitoring"
draft-ietf-eman-battery-mib-17.txt, December 2014.
[ESTAR] http://www.energystar.gov/
[ISO] http://www.iso.org/iso/pressrelease.htm?refid=Ref1434
[ASHRAE] http://collaborate.nist.gov/twiki-
sggrid/bin/view/SmartGrid/PAP17Information
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[ZIGBEE] http://www.zigBee.org/
[ANSICEA] ANSI/CEA-2047, Consumer Electronics - Energy Usage
Information (CE-EUI), 2013.
[ISO] http://www.iso.org/iso/pressrelease.htm?refid=Ref1337
[PWG5106.4]IEEE-ISTO PWG Power Management Model for Imaging
Systems v1.0, PWG Candidate Standard 5106.4-2011,
February 2011.ftp://ftp.pwg.org/pub/pwg/candidates/cs-
wimspower10-20110214-5106.4.mib
[PWG5106.5] IEEE-ISTO PWG Imaging System Power MIB v1.0, PWG
Candidate Standard 5106.5-2011, February 2011.
[IEC62301] International Electrotechnical Commission, "IEC 62301
Household electrical appliances Measurement of standby
power", Edition 2.0, 2011.
[MODBUS] Modbus-IDA, "MODBUS Application Protocol Specification
V1.1b", December 2006.
[NIST] http://www.nist.gov/smartgrid/
[RFC3805] Bergman, R., Lewis, H., and McDonald, I. "Printer MIB
v2", RFC 3805, June 2004.
[RFC6933] Bierman, A., Romascanu, D., Quittek, J., and
Chandramouli, M., "Entity MIB v4", RFC 6933, May 2013.
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Authors' Addresses
Brad Schoening
44 Rivers Edge Drive
Little Silver, NJ 07739
USA
Phone: +1 917 304 7190
Email: brad.schoening@verizon.net
Mouli Chandramouli
Cisco Systems, Inc.
Sarjapur Outer Ring Road
Bangalore 560103
India
Phone: +91 80 4429 2409
Email: moulchan@cisco.com
Bruce Nordman
Lawrence Berkeley National Laboratory
1 Cyclotron Road, 90-4000
Berkeley 94720-8136
USA
Phone: +1 510 486 7089
Email: bnordman@lbl.gov
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