Internet DRAFT - draft-tychon-eman-applicability-statement
draft-tychon-eman-applicability-statement
Energy Management Working Group E. Tychon
Internet Draft Cisco Systems Inc.
Intended status: Informational B. Schoening
Expires: April 31, 2012 Independent Consultant
Mouli Chandramouli
Cisco Systems Inc.
Bruce Nordman
Lawrence Berkeley National Laboratory
October 31, 2011
Energy Management (EMAN) Applicability Statement
draft-tychon-eman-applicability-statement-05
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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 framework for a variety
of scenarios. This document lists use cases and target devices
that can potentially implement the EMAN framework and associated
SNMP MIB modules. These use cases are useful for identifying
monitoring requirements that need to be considered. Further, we
describe the relationship of the EMAN framework to relevant
other energy monitoring standards and architectures.
Table of Contents
1. Introduction ................................................3
1.1. Energy Management Overview
..............................4
1.2. Energy Measurement
......................................5
1.3. Energy Management
.......................................5
1.4. EMAN Framework Application
..............................6
1.5. EMAN WG Document Overview
...............................6
2. Scenarios and Target Devices
................................7
2.1. Network Infrastructure Energy Objects
...................7
2.2. Devices Powered and Connected to a Network Device
.......8
2.3. Devices Connected to a Network
..........................9
2.4. Power Meters
............................................9
2.5. Mid-level Managers
.....................................10
2.6. Gateways to Building Systems
...........................11
2.7. Home Energy Gateways
...................................12
2.8. Data Center Devices
....................................13
2.9. Energy Storage Devices ................................14
2.10. Ganged Outlets on a PDU Multiple Power Sources ........14
2.11. Industrial Automation Networks
......................15
2.12. Printers
...................................15
2.13. Off-Grid Devices
......................................17
2.14. Demand/Response
.....................................17
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2.15. Power Capping
........................................18
3. Use Case Patterns
..........................................18
3.1. Metering
...............................................18
3.2. Metering and Control
...................................19
3.3. Power Supply, Metering and Control
.....................19
3.4. Multiple power sources
.................................19
4. Relationship of EMAN to other Standards
....................19
4.1. Data Model and Reporting
...............................20
4.1.1. IEC - CIM. ......................................20
4.1.2. DMTF ............................................20
4.1.3. ODVA ............................................21
4.1.4. Ecma SDC ........................................22
4.1.5. IEEE-ISTO Printer Working Group (PWG) ...........22
4.1.6. ASHRAE ..........................................23
4.1.7. ZigBee ..........................................24
4.2. Measurement
............................................24
4.2.1. ANSI C12 ........................................24
4.2.2. IEC62301 ........................................24
4.3. Other
..................................................25
4.3.1. ISO .............................................25
4.3.2. EnergyStar ......................................26
4.3.3. SmartGrid .......................................26
5. Limitations
................................................27
6. Security Considerations
....................................27
7. IANA Considerations
........................................27
8. Acknowledgements
...........................................27
9. Open Issues
...............................................28
10. References
................................................28
10.1. Normative References
..................................28
10.2. Informative References
................................29
1. Introduction
The focus of the Energy Management (EMAN) framework is energy
monitoring and management of energy objects [EMAN-DEF]. The
scope of devices considered are network equipment and its
components, and devices connected directly or indirectly to
the network. The EMAN framework enables monitoring i.e.;
heterogeneous devices to report their energy consumption, and
secondly, if permissible, enables control policies for energy
savings. There are multiple scenarios where this is
desirable, particularly considering the increased importance
of limiting consumption of finite energy resources and
reducing operational expenses.
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The EMAN framework 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. Other
standards that are similar to EMAN but address different domains
are described. This document contains references to those other
standards and describes how they relate to the EMAN framework.
1.1. Energy Management Overview
First, a brief introduction to the definitions of Energy and
Power are presented. A draft on terminology has been submitted
so that to reach a consensus on the definitions of commonly used
terms in the EMAN WG. While energy is available in many forms,
EMAN addresses only the electrical energy consumed by devices
connected to a network.
Energy is the capacity to perform work. Electrical energy is
typically expressed in kilowatt-hour units (kWh) or other
multiples of watt-hours (Wh). One kilowatt-hour is the
electrical energy used by a 1 kilowatt device for one hour.
Power is the rate of electrical energy flow. In other words,
power = energy / time. Power is often measured in watts. Billing
is based on electrical energy (measured in kWh) supplied by the
utility.
Towards the goal of increasing the energy efficiency in networks
and buildings, a first step is to enable energy objects to
report their energy usage over time. The EMAN framework
addresses this problem with an information model for some
electrical equipment: energy object identification, energy
object context, power measurement and power measurement
attributes.
The EMAN WG framework defines SNMP MIB modules based on the
information model. By implementing the SNMP MIB modules, any
energy object can report its energy consumption according to the
information model. In that context, it is important to
distinguish energy objects that can report their own energy
usage from parent devices that can also collect and aggregate
energy usage of children energy objects.
The list of target devices and scenarios considered for Energy
Management are presented in Section 2 with detailed examples.
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1.2. Energy Measurement
More and more devices are able to measure and report their own
energy consumption. Smart 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 minimally useful at the enterprise
level.
The primary goal of the EMAN MIBs 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 at
any time by leveraging existing networks, across various
equipment, in a unified and consistent manner.
Given that an energy object can consume energy and/or provide
energy to other devices, there are three types of meters for
energy measurement: energy input to a device, energy supplied to
other devices, and net (resultant) energy consumed (the
difference between energy input and provided).
1.3. Energy Management
Beyond energy monitoring, the EMAN framework provides mechanisms
for energy control.
There are many cases where reducing energy consumption of
devices is desirable, such as when the device utilization islow
or when the electricity is expensive or in short supply.
In some cases, energy control requires considering the energy
object context. For instance, in a building: all phones would
not usually be turned off to keep some still available in case
of emergency; office cooling is usually not turned off totally
during non-work hours, but the comfort level is reduced; and so
on.
Energy object control requires flexibility and support for
different polices and mechanisms: from centralized management
with a network management station, to autonomous management by
individual devices, and alignment with dynamic demand-response
mechanisms.
The EMAN framework can be used as a tool for the demand/response
scenario where in response to time-of-day fluctuation of energy
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costs or possible energy shortages, it is possible to respond
and reduce the energy consumption for the network devices,
effectively changing its power state.
1.4. EMAN Framework Application
A Network Management System (NMS) is the entity that requests
information from compatible devices using SNMP protocol. It may
be a system which also implements other network management
functions, e.g. security management, identity management and so
on), or one that only deals exclusively with energy in which
case it is called EnMS, Energy Management System. It may be
limited to monitoring energy use, or it may also implement
control functions. In a typical application of the EMAN
framework, management software collects energy information for
devices in the network.
Energy management can be implemented by extending existing SNMP
support to the 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. The scope of the target devices and the
network scenarios considered for energy management are listed in
Section 2.
1.5. EMAN WG Document Overview
The EMAN working group charter calls for producing a series of
Internet standard drafts in the area of energy management. The
following drafts are currently under discussion in the working
group.
Applicability Statement [EMAN-AS] This draft presents the use
cases and scenarios for energy monitoring. In addition, other
relevant energy standards and architectures are listed.
Requirements [EMAN-REQ] This draft presents the requirements
of Energy Monitoring and the scope of the devices considered.
Framework [EMAN-FRAMEWORK] This draft defines the terminology
and explains the different concepts associated with energy
monitoring; these are used in the MIB modules.
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Energy-Aware MIB [EMAN-AWARE-MIB] This draft proposes a MIB
module that characterizes a device's identity and context.
Monitoring MIB [EMAN-MONITORING-MIB] This draft defines a MIB
module for monitoring the power and energy consumption of a
device. In addition, the MIB module contains an optional
module for power quality metrics.
Battery MIB [EMAN-BATTERY-MIB] This draft contains a MIB
module for monitoring characteristics of an internal battery.
Energy Management Terminology [EMAN-DEF] This draft lists the
definitions and terms used in the Energy Management Working
Group.
2. Scenarios and Target Devices
In this section a selection of scenarios for energy management
are presented. The fundamental objective of the use cases is to
list important network scenarios that the EMAN framework should
solve. These use cases then drive the requirements for the EMAN
framework.
Each scenario lists target devices for which the energy
management framework can be applied, as well as how the
reported-on devices are powered, and how the reporting is
accomplished. While there may be some overlap between some of
the use cases, the use cases serve as illustrative network
scenarios EMAN framework should solve.
2.1. Network Infrastructure Energy Objects
This scenario covers network devices and their components. Power
management of energy objects is considered as a fundamental
requirement of energy management of networks.
It can be important to monitor the power state and energy
consumption of these energy objects at a granularity level finer
than just the entire device. For these devices, the chassis
draws power from one or more sources and feeds all its internal
components. It is highly desirable to have monitoring available
for individual components, such as line cards, processors, and
hard drives as well as peripherals like USB devices.
As an illustrative example, consider a switch with the following
grouping of sub-entities for which energy monitoring could be
useful.
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. physical view: chassis (or stack), line cards, service
modules of the switch
. component view: CPU, ASICs, fans, power supply, ports
(single port and port groups), storage and memory
. logical view: system, data-plane, control-plane, etc.
The essential properties of this use case are:
. Target devices: Network devices such as routers, switches
and their components.
. How powered: Typically by a 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 that can report on behalf of
some components.
2.2. Devices Powered and Connected to a Network Device
This scenario covers Power over Ethernet (PoE) devices. A PoE
Power Sourcing Equipment (PSE) device (e.g. a PoE switch)
provides power to a Powered Device (PD) (e.g. a desktop phone).
For each port, the PSE can control the power supply (switching
it on and off) and monitor actual power provided. PoE devices
obtain network connectivity as well as the power supply for the
device over a single connection so the PSE can determine which
device to allocate each port's power to.
PoE ports on a switch are commonly connected to IP phones,
wireless access points, and IP cameras. The switch powers
itself, as well as supplies power to downstream PoE ports.
Monitoring the power consumption of the switch (Energy Object
Parent) and the power consumption of the PoE end-points(Energy
Object Children) is a simple use case of this scenario.
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 often measured
and reported at the switch (PSE) port which supplies power
for the PoE device.
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In this case, the PoE devices do not need to directly support
the EMAN framework, only the Power Sourcing Equipment (PSE)
does.
2.3. Devices Connected to a Network
The use case covers the metering relationship between an energy
object receiving power from a source such as a power brick, and
have an independent network connection to a parent energy object
such as a switch.
In continuation to the previous example is a switch port that
has both a PoE connection powering an IP Phone, and a PC has a
daisy-chain connection to the IP Phone for network connectivity.
The PC has a network connection from the switch, but draws power
from the wall outlet, in contrast to the IP phone draws power
from the switch.
It is also possible to consider a simple example of PC which has
a network connection but draws power from the wall outlet or
PDU.
The PC in this case, is an non-PoE device, can report power
usage by itself, for instance through the EMAN framework.
The essential properties of this use case are:
. Target devices: Abroad set of energy objects that have a
network connection, but receive power supply from the wall
outlet.
. How powered: These devices receive power supply from the
wall outlet or a PDU.
. Reporting: There are two models: devices that can measure
and report the power consumption directly via the EMAN
framework, and those that communicate it to the network
device (switch) and the switch can report the device's
power consumption via the EMAN framework.
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.
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This use case covers the proxy relationship of energy objects
able to measure or report the power consumption of external
electrical devices, not natively connected to the network.
Examples of such metering devices are smart PDUs and smart
meters.
Three types of external metering are relevant to EMAN: PDUs,
standalone meters, and utility meters. External meters can
measure these properties for a single device or for a set of
devices.
Power Distribution Unit (PDUs) in a rack have inbuilt meters for
each socket and the PDUs can measure the power supplied to each
device in an equipment rack. The PDUs have remote management
functionality which can be used to measure and possibly control
the power supply of each outlet.
Standalone meters can be placed anywhere in a power distribution
tree, and can measure the power consumption.
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 Smart Meters.
. How powered: From traditional mains power but as passed
through a PDU or meter.
. Reporting: The PDUs reports power consumption of
downstream devices. There is commonly only one device
downstream of each outlet, but there could be many. There
can be external meters in between the power supply and
device and the meters can report the power consumption of
the device.
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 as well as 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
devices it does not supply power to them. Devices report their
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EMAN data to the switch and the switch aggregates the data for
these data.
The essential properties of this use case are summarized as
follows:
. Target devices: network devices which can perform
aggregation; commonly a switch or a proxy
. How powered: Mid-level managers can be are commonly
powered by a PDU or from a wall outlet but there is no
limitation.
. Reporting: The middle-manager aggregates the energy data
and reports that data to a NMS or higher mid-level manager.
2.6. Gateways to Building Systems
This use case describes energy management of 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 relationship between IP and legacy building
automation protocols. The gateway can provide 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 ofa 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 between many facility
management devices. The gateway communicates via RS-232/RS-485
interfaces, Ethernet interfaces, and protocols specific to
building management such as BACNET, MODBUS, or Zigbee.
The essential properties of this use case are :
. Target devices: Building energy management devices - HVAC
systems, lighting, electrical, fire and emergency systems.
There are meters for each of the sub-systems and the energy
data is communicated to the proxy using legacy protocols.
. How powered: Any method, including directly from mains
power or via a UPS.
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. 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 to the electrical appliances and other devices in a
home and also has an interface to the utility. This gateway can
monitor and manage electrical equipment (refrigerator,
heating/cooling, washing machine etc.) possibly using one of the
many protocols (ZigBee, Smart Energy, ...) that are being
developed for the home area network products and considered in
standards organizations.
In its simplest form, metering can be performed at home. Beyond
the metering, it is also possible implement energy saving
policies based on energy pricing from the utility grid. From an
EMAN point of view, the information model that been investigated
can be applied to the protocols under consideration for energy
monitoring of a home.
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.
Beyond the canonical setting of a home drawing power from the
utility, it is also possible to envision an energy neutral
situation wherein the buildings/homes that can produce and
consume energy without importing energy from the utility grid.
There are many energy production technologies such as solar
panels, wind turbines, or micro generators. This use case
illustrates the concept of self-contained energy generation and
consumption and possibly the aggregation of the energy use of
homes.
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2.8. Data Center Devices
This use case describes energy management of a Data Center
network.
Energy efficiency of data centers has become a fundamental
challenge of data center operation, as datacenters are big
energy consumers and their infrastructure is expensive. The
equipment generates heat, and heat needs to be evacuated though
a HVAC system.
A typical data center network consists of a hierarchy of
electrical energy objects. At the bottom are servers mounted on
a rack; these are connected to the top-of-the-rack switches;
these are connected to aggregation switches; those in turn
connected to core switches. Power consumption of all network
elements and the servers in the Data center should be measured.
In addition, there are also network storage devices. Energy
management can be implemented on different aggregation levels,
such as network level, Power Distribution Unit (PDU) level, and
server level.
The Data center network contains UPS to provide back-up power
for the network devices in the event in the event of power
outages. Thus from a Data center energy management point of
view, in addition, to monitoring the energy usage of network
devices, it is also important to monitor the remaining capacity
of the UPS.
In addition to monitoring the power consumption, at a data
center level, additional metrics such as power quality, power
characteristics can be important metrics. The dynamic variations
in the input power supply from the grid referred to as power
quality is one metric. Secondly, how the devices use the power
can be referred to as power characteristics and it is also
useful to monitor these metrics. Lastly, the power plate set
will make it possible to know an aggregate of the potential
worst-case power usage and compare it to the budgeted power in
the data center.
The essential properties of this use case are:
. Target devices: All network devices in a data center, such
as network equipment, servers, and storage devices.
. How powered: Any method but commonly by a PDUs in racks.
. Reporting: Devices may report on their own behalf, or for
other connected devices as described in other use cases.
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2.9. Energy Storage Devices
There are two types of devices with energy storage: those whose
primary function is to provide power to another device (e.g. a
UPS), and those with a different primary function, but have an
energy storage as a component as an alternate internal power
source (e.g. a notebook). EMAN covers both types of products in
this use case.
The energy storage can be a battery, or any other means to store
electricity such as a hydrogen cell.
Some devices have an internal battery as a back-up or
alternative source of power to mains power. When the connection
to the power supply of the device is disconnected, the device
can run on the internal battery. As batteries have a finite
capacity and lifetime, means for reporting the actual charge,
age, and state of a battery are required.
UPS can provide backup power for many devices in a data centers
for a finite period of time. Energy monitoring of such energy
storage devices is vital from a data center network operations
point of view. The UPS MIB provides a framework for monitoring
the remaining capacity of the UPS.
There are also battery systems for mobile towers particularly
for use in remote locations. It is important to monitor the
remaining battery life and raise an alarm when the battery life
is below a threshold.
The essential properties of this use case are:
. Target devices: Devices that have an internal battery such
as notebook PC and other mobile devices.
. How powered: From internal batteries or mains power.
. Reporting: The device reports on its internal battery.
2.10. Ganged Outlets on a PDU Multiple Power Sources
This use case describes the scenario of multiple power sources
of a devices and logical groupings of devices in a PDU.
Some PDUs allow physical entities like outlets to be "ganged"
together as a logical entity to simplify management.
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This is particularly useful for servers with multiple power
supplies, where each power supply is connected to a different
physical outlet. Other implementations allow "gangs" to be
created based on common ownership of outlets, such as business
units, load shed priority, or other non-physical relationships.
Current implementations allow for an "M-to-N" mapping between
outlet "gangs" and physical outlets, as with this example:
. Outlet 1 - physical entity
. Outlet 2 - physical entity
. Outlet 3 - physical entity
. Outlet 4 - physical entity
. Outlet Gang A - virtual entity
. Outlet Gang B - virtual entity
o Gang A -> Outlets 1, 2 and 3
o Gang B -> Outlets 3 and 4
Note the allowed overlap on Outlet 3, which belongs to both
"gangs."
Each "Outlet Gang" entity reports the aggregated data from the
individual outlet entities that comprise it and enables a single
point of control for all the individual outlet entities.
2.11. 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, making it the largest end-
use sector. Thus, the need for optimization of energy usage in
this sector is natural.
Industrial facilities consume energy in process loads, and in
non-process loads.
The essential properties of this use case are:
. Target devices: Devices used in industrial automation
. How powered: Any method.
. Reporting: Currently, CIP protocol is currently used for
reporting energy for these devices
2.12. Printers
This use case describes the scenario of energy monitoring and
management of Printer devices.
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Printers in this use case stand in for all imaging equipment,
also including multi-function devices (MFDs), copiers, scanners,
fax machines, and mailing machines. Energy use of printers has
been an industry concern for several decades, and they usually
have sophisticated power management with 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, and cross-vendor management systems are available
today to manage fleets of printers in enterprises. Power
consumption during active modes can vary widely, with high peak
levels.
Printers today 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 setting of
policies such as delay times when no activity will cause
automatic transition to a lower power mode. Other features
include reporting on components of imaging equipment, counters
for state transitions, and 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
imaging system. These will 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 monitoring. While the printer is not in use,
there are timer based low power states (sleep, stand-by), which
consume very little power. On the other hand, while the printer
is printing or copying the cylinder needs to be heated so that
power consumption is quite high but only for a short period of
time (duration of the print job). Given this work load, periodic
polling of energy consumption would not suffice.
Target Devices: All imaging equipment.
How Powered: Typically via mains AC from a wall outlet
Reporting: Devices report for themselves
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2.13. Off-Grid Devices
This use case concerns self-contained devices that use energy
but are not connected to an infrastructure power delivery grid.
These devices typically scavenge energy from environmental
sources such as solar energy or wind power. The device generally
contains a closely coupled combination of
. power scavenging or generation component(s)
. power storage component(s) (e.g., battery)
. power consuming component(s)
With scavenged power, the energy input is often dependent on the
random variations of the weather. These devices therefore
require energy management both for internal control and remote
reporting of their state. In order to optimize the performance
of these devices and minimize the costs of the generation and
storage components, it is desirable to vary the activity level,
and, hopefully, the energy requirements of the consuming
components in order to make best use of the available stored and
instantaneously generated energy. With appropriate energy
management, the overall device can be optimized to deliver an
appropriate level of service without over provisioning the
generation and storage components.
In many cases these devices are expected to operate
autonomously, as continuous communications for the purposes of
remote control is either impossible or would result in excessive
power consumption. Non continuous polling requires the ability
to store and access later the information collected while the
communication was not possible.
Target Devices: Remote network devices (mobile network) that
consume and produce energy
How Powered: Can be battery powered or using natural energy
sources
Reporting: Devices report their power usage but only
occasionally.
2.14. Demand/Response
Demand/Response from the utility or grid is a common theme that
spans across some of the use cases. In some situations, in
response to time-of-day fluctuation of energy costs or sudden
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energy shortages due power outages, it may be important to
respond and reduce the energy consumption of the network.
From EMAN use case perspective, the demand/response scenario can
apply to a Data Center or a Building or a residential home. As a
first step, it may be important to monitor the energy
consumption in real-time of a Data center or a building or home
which is already discussed in the previous use cases. Then based
on the potential energy shortfall, the Energy Management System
(EMS) could formulate a suitable response, i.e., the EMS could
shut down some selected devices that may be considered
discretionary or uniformly reduce the power supplied to all
devices. For multi-site data centers it may be possible to
formulate policies such as follow-the-moon type of approach, by
scheduling the mobility of VMs across Data centers in different
geographical locations.
2.15. Power Capping
Power capping is a technique to limit the total power
consumption of a server. This technique can be useful for power
limited data centers. Based on workload measurements, the server
can choose the optimal power state of the server in terms of
performance and power consumption. When the server operates at
less than the power supply capacity, it runs at full speed. When
the server power would be greater than the power supply
capacity, it runs at a slower speed so that its power
consumption matches the available power supply capacity. This
gives vendors the option to use smaller, cost-effective power
supplies that allow real world workloads to run at nominal
frequency.
3. Use Case Patterns
The use cases presented above can be abstracted to the following
broad patterns.
3.1. Metering
-energy objects which have capability for internal metering
- electrical devices which are metered by an external device
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3.2. Metering and Control
- entities objects that do not supply power, butcan perform only
power metering for other devices
- entities objects that do not supply power, can perform both
metering and control for other devices
3.3. Power Supply, Metering and Control
- entities devices that supply power for other devices but do
not perform power metering for those devices
- entities that supply power for other devices and also perform
power metering
- entities supply power for other devices and also perform power
metering and control for other devices
3.4. Multiple power sources
- entities that have multiple power sources and metering and
control is performed by one source
- entities that have multiple power sources and metering is
performed by one source and control another source
4. Relationship of EMAN to other Standards
EMAN as a framework is tied to other standards and efforts that
deal with energy. Existing standards are leveraged when
possible. EMAN helps enable adjacent technologies such as Smart
Grid.
The standards most relevant and applicable to EMAN are listed
below with a brief description of their objectives, the current
state and how that standard can be applied to EMAN.
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4.1. Data Model and Reporting
4.1.1. IEC - CIM
The International Electro-technical 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 was originally conceived to automate
control of a substation (facilities which transfer electricity
from the transmission to the distribution system). While the
original domain of 61850 is substation automation, the extensive
data model has been widely used in other domains, including
Energy Management Systems (EMS).
IEC TC57 WG19 is an ongoing working group to harmonize the CIM
data model and 61850 standards.
Concepts from IEC Standards have been reused in the EMAN WG
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 reused IEC 62053-21 and
IEC 62053-22.
4.1.2. DMTF
The Distributed Management Task Force (DMTF)[DMTF] has
standardized management solutions for managing servers and PCs,
including power-state configuration and management of elements
in a heterogeneous environment. These specifications provide
physical, logical and virtual system management requirements for
power-state control.
The EMAN standard references the DMTF Power Profile and Power
State Series.
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),
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'Power State' (DSP 1027) and 'Power Utilization Management' (DSP
1085).These profiles define monitoring and configuration of a
Power Managed Element's static and dynamic power saving modes,
power allocation limits and power states, among other features.
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 ACPI and DMTF power state
models, although it is not necessary for a managed element to
support ACPI. Optionally, a TransitingToPowerState property can
represent power state transitions in progress.
4.1.2.2. DASH
DMTF DASH (DSP0232) (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 provides management and control of managed
elements like power, CPU, etc. using the DMTF's WS-Management
web services and CIM data model.
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 and defines the Common
Industrial Protocol (CIP). Within ODVA, there is a special
interest group focused on energy.
There are many similar concepts between the ODVA and EMAN
frameworks towards monitoring and management of energy aware
devices. In particular, one of the concepts being considered
different energy meters based on if the device consumes
electricity or produces electricity or a passive device.
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The Open DeviceNet Vendors Association (ODVA) is developing an
energy management framework for the industrial sector. There
are synergies between the ODVA and EMAN approaches to energy
management.
ODVA defines a three-part approach towards energy management:
awareness of energy usage, consuming energy more efficiently,
and exchanging energy with the 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 committee on Smart Data Centre (TC38-TG2
SDC [Ecma-SDC]) is in the process of defining 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 power measurements in kWor kWh.
The 14th draft of SDC process was published in March 2011 and
the development of the standard is still underway. 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. IEEE-ISTO Printer Working Group (PWG)
The IEEE-ISTO Printer Working Group (PWG) defines SNMP MIB
modules for printer management and has recently defined 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
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the DMTF CIM Infrastructure [DSP0004] and DMTF CIM Power State
Management Profile [DSP1027] for power states and alerts.
The PWG would like its MIBs to be harmonized as closely as
possible with those from EMAN. The PWG covers many topics in
greater detail than EMAN, as well as some that are specific to
imaging equipment. The PWG also provides for vendor-specific
extension states (i.e., beyond the standard DMTF CIM states.)
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 American Society of
Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
and National Electrical Manufacturers Association (NEMA), both
ANSI approved SDO's. The result is to be an information model,
not a device level monitoring 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 any new protocols.
There are four basic types of entities in the model: generators,
loads, meters, and energy managers.
The metering part of this model overlaps with the EMAN framework
to a large degree, 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 is expected soon,
and at that point detailed comparison of the two models can be
made. There are no apparent major conflicts between the two
approaches, but there are likely areas where some harmonization
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is possible, and regardless, a description of the
correspondences would be helpful to create.
4.1.7. ZigBee
The Zigbee Smart Energy 2.0 effort[ZIGBEE] focuses on wireless
communication to appliances and lighting. It is intended to
enable building energy management and enable direct load control
by utilities.
ZigBee protocols are intended for use in embedded applications
requiring low data rates and low power consumption. ZigBee
defines a general-purpose, inexpensive, self-organizing mesh
network that can be used for industrial control, embedded
sensing, medical data collection, smoke and intruder warning,
building automation, home automation, etc.
Zigbee is currently not an ANSI recognized SDO.
The EMAN framework addresses the needs of IP-enabled networks
through the usage of SNMP, while Zigbee looks for completely
integrated and inexpensive mesh solution.
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.ANSI C12.20 defines accuracy classes for watt-hour
meters.
All of these standards are oriented toward the meter itself, and
are therefore very specific and used by electricity distributors
and producers.
The EMAN standard references ANSI C12 accuracy classes.
4.2.2. IEC62301
IEC 62301, "Household electrical appliances Measurement of
standby power", specifies a power level measurement procedure.
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While nominally for appliances and low-power modes, many aspects
of it 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, many aspects of it are
informative to those implementing measurement in products that
ultimately report via EMAN.
4.3. Other
4.3.1. ISO
The ISO [ISO] is developing an energy management standard, ISO
50001, to complement ISO 9001 for quality management, and ISO
14001 for environment management. The intent of the framework is
to facilitate the creation of energy management programs for
industrial, commercial and other entities. The standard defines
a process for energy management at an organization level. It
does not define the way in which devices report energy and
consume energy.
EMAN is complementary to ISO 9001.
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 (quality management) and ISO 14001
(environmental management). ISO 50001 benefits includes:
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.
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4.3.2. EnergyStar
The US Environmental Protection Agency (EPA) and US 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 EnergyStar, one
being a protocol and the other a set of recommendations to
develop energy efficient products. However, Energy Star could
include EMAN standards in specifications for future products,
either as required or rewarded with some benefit.
4.3.3. SmartGrid
The Smart Grid standards efforts underway in the United States
are overseen by the US 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. The
NIST smart grid standards 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.
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. There are currently 17 PAPs. PAP 17 is discussed in
section 4.1.6.
PAP 10 addresses "Standard Energy Usage Information".
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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-load pricing periods. These actions can
be effected through both centralized and distributed management
controls.
There is an obvious functional link between SmartGrid and EMAN
in the form of demand response, even if the EMAN framework does
not take any specific step toward SmartGrid communication.
5. Limitations
EMAN Framework shall address 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.
The EMAN framework does not address questions regarding
SmartGrid, electricity producers, and distributors even if there
is obvious link between them.
6. Security Considerations
EMAN shall use SNMP protocol for energy monitoring and thus has
the functionality of SNMP's security capabilities. SNMPv3
[RFC3411] provides important security features such as
confidentiality, integrity, and authentication.
7. IANA Considerations
This memo includes no request to IANA.
8. Acknowledgements
The authors would like to thank Jeff Wheeler, Benoit Claise,
Juergen Quittek, Chris Verges, John Parello, and Matt Laherty,
for their valuable contributions.
The authors would like to thank Georgios Karagiannis for use
case involving energy neutral homes, Elwyn Davies for off-grid
electricity systems, and Kerry Lynn for the comment on the
Demand/Response scenario.
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9. Open Issues
"EDITOR NOTE: use the latest definition from draft-parello-eman-
definitions"
OPEN ISSUE 1: Relevant IEC standards for application for EMAN
Applicability Statement document can provide guidance on the
issue of what is appropriate standard used by EMAN
IEC 61850-7-4 has been extensively used in EMAN WG documents.
The other IEC documents referred for possible use are IEC
61000-4-30, IEC 62053-21 and IEC 62301.
There is feedback that IEC 61850-7-4 applies only to sub-
stations ?
OPEN ISSUE 2: Should review ASHRAE SPC 201P standard when it is
released for public review
. Need to review ASHRAE information model and the use cases
and how it relates to EMAN
OPEN ISSUE 3: Review ALL requirements to ensure that they can be
traced to a use case
. Missing is an use case for power quality
OPEN ISSUE 4: Question for the WG. Should we have unique use
cases that introduce specific requirements ? or can there be
some overlap between use cases ?
Any use cases out of scope scenarios ?
10. References
10.1. Normative References
[RFC3411] An Architecture for Describing Simple Network
Management Protocol (SNMP) Management Frameworks, RFC
3411, December 2002.
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10.2. Informative References
[DASH] "Desktop and mobile Architecture for System Hardware",
http://www.dmtf.org/standards/mgmt/dash/
[NIST] http://www.nist.gov/smartgrid/
[Ecma-SDC] Ecma TC38 / SDC Task Group, "Smart Data Centre
Resource Monitoring and Control (DRAFT)", March 2011.
[ENERGY] http://en.wikipedia.org/wiki/Kilowatt_hour
[EMAN-AS] Tychon, E., B. Schoening,MouliChandramouli, Bruce
Nordman, "Energy Management (EMAN) Applicability
Statement", draft-tychon-eman-applicability-statement-
04.txt, work in progress, October 2011.
[EMAN-REQ] Quittek, J., Winter, R., Dietz, T., Claise, B., and
M. Chandramouli, "Requirements for Energy Management ",
draft-ietf-eman-requirements-04 (work in progress),July
2011.
[EMAN-MONITORING-MIB] M. Chandramouli, Schoening, B., Dietz, T.,
Quittek, J. and B. Claise "Energy and Power Monitoring
MIB ", draft-ietf-eman-monitoring-mib-00,August 2011.
[EMAN-AWARE-MIB] J. Parello, and B. Claise, "draft-ietf-eman-
energy-aware-mib-02", work in progress, July 2011.
[EMAN-FRAMEWORK] Claise, B., Parello, J., Schoening, B., and J.
Quittek, "Energy Management Framework", draft-ietf-
eman-framework-02 ,July 2011.
[EMAN-BATTERY-MIB] Quittek, J., Winter, R., and T. Dietz,
"Definition of Managed Objects for Battery Monitoring"
draft-ietf-eman-battery-mib-02.txt, July 2011.
[EMAN-DEF] J. Parello"Energy Management Terminology", draft-
parello-eman-definitions-03
[DMTF] "Power State Management ProfileDMTFDSP1027 Version 2.0"
December2009.
http://www.dmtf.org/sites/default/files/standards/docum
ents/DSP1027_2.0.0.pdf
[ESTAR] http://www.energystar.gov/
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[ISO] http://www.iso.org/iso/pressrelease.htm?refid=Ref1434
[SGRID] http://collaborate.nist.gov/twiki-
sggrid/bin/view/SmartGrid/SGIPWorkingGroupsAndCommittee
s
[ASHRAE] http://collaborate.nist.gov/twiki-
sggrid/bin/view/SmartGrid/PAP17Information
[PAP17] http://collaborate.nist.gov/twiki-
sggrid/bin/view/SmartGrid/PAP17FacilitySmartGridInforma
tionStandard
[ZIGBEE] http://www.zigbee.org/
[ISO] http://www.iso.org/iso/pressrelease.htm?refid=Ref1337
[DSP0004] DMTF Common Information Model (CIM) Infrastructure,
DSP0004, May 2009.
http://www.dmtf.org/standards/published_documents/DSP00
04_2.5.0.pdf
[DSP1027] DMTF Power State Management Profile, DSP1027, December
2009.
http://www.dmtf.org/standards/published_documents/DSP10
27_2.0.0.pdf
[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.
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Authors' Addresses
Emmanuel Tychon
Cisco Systems, Inc.
De Keleetlaan, 6A
B1831 Diegem
Belgium
Email: etychon@cisco.com
Brad Schoening
44 Rivers Edge Drive
Little Silver, NJ 07739
USA
Email:brad@bradschoening.com
MouliChandramouli
Cisco Systems, Inc.
Sarjapur Outer Ring Road
Bangalore,
India
Phone: +91 80 4426 3947
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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