Skip to main content
Energy Management Framework
Energy Management Framework
draft-ietf-eman-framework-07
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 7326.
|
|
|---|---|---|---|
| Authors | Benoît Claise , John Parello , Brad Schoening , Juergen Quittek , Bruce Nordman | ||
| Last updated | 2013-06-11 (Latest revision 2013-02-25) | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | Eliot Lear | ||
| IESG | IESG state | Became RFC 7326 (Informational) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | Joel Jaeggli | ||
| Send notices to | (None) |
draft-ietf-eman-framework-07
Network Working Group B. Claise
Internet-Draft J. Parello
Intended Status: Informational Cisco Systems, Inc.
Expires: July 12, 2013 B. Schoening
Independent Consultant
J. Quittek
NEC Europe Ltd.
B. Nordman
Lawrence Berkeley
National Laboratory
February 24, 2013
Energy Management Framework
draft-ietf-eman-framework-07
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance
with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet
Engineering Task Force (IETF), its areas, and its working
groups. Note that other groups may also distribute working
documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other
documents at any time. It is inappropriate to use Internet-
Drafts as reference material or to cite them other than as
"work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed
at http://www.ietf.org/shadow.html
This Internet-Draft will expire on July, 2013.
<Claise, et. Al> Expires Jul 12 2013 [Page 1]
Internet-Draft <EMAN Framework> February 2013
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as
the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date
of publication of this document. Please review these
documents carefully, as they describe your rights and
restrictions with respect to this document. Code Components
extracted from this document must include Simplified BSD
License text as described in Section 4.e of the Trust Legal
Provisions and are provided without warranty as described in
the Simplified BSD License.
Abstract
This document defines a framework for providing Energy
Management for devices and device components within or
connected to communication networks. The framework defines an
Energy Management Domain as a set of Energy Objects, for which
each Energy Object is identified, classified and given
context. Energy Objects can be monitored and/or controlled
with respect to Power, Power State, Energy, Demand, Power
Attributes, and Battery. Additionally the framework models
relationships and capabilities between Energy Objects.
<Claise, et. Al> Expires August, 2013 [Page 2]
Internet-Draft <EMAN Framework> February 2013
Table of Contents
1. Introduction
.......................................... 5
2. Terminology
........................................... 6
Device................................................. 6
Component.............................................. 6
Energy Management...................................... 6
Energy Management System (EnMS)........................ 7
Power.................................................. 8
Demand................................................. 8
Power Attributes....................................... 8
Power Quality.......................................... 9
Electrical Equipment................................... 9
Non-Electrical Equipment (Mechanical Equipment)........ 9
Energy Object......................................... 10
Electrical Energy Object.............................. 10
Non-Electrical Energy Object.......................... 10
Energy Monitoring..................................... 10
Energy Control........................................ 10
Provide Energy:....................................... 10
Receive Energy:....................................... 11
Power Interface....................................... 11
Energy Management Domain.............................. 11
Energy Object Identification.......................... 11
Energy Object Context................................. 11
Energy Object Relationship............................ 12
Aggregation Relationship.............................. 12
Metering Relationship................................. 12
Power Source Relationship............................. 12
Proxy Relationship.................................... 12
Energy Object Parent.................................. 13
Energy Object Child................................... 13
Power State........................................... 13
Power State Set....................................... 13
Nameplate Power....................................... 13
3. Issues Specific to Energy Management ................. 13
3.1. Power Supply .................................... 15
3.2. Power and Energy Measurement .................... 20
3.3. Reporting Sleep and Off States .................. 21
3.4. Device and Device Components .................... 22
3.5. Non-Electrical Equipment ........................ 23
4. 4. Energy Management Abstraction ..................... 23
4.1. Energy Object and Energy Management Domain ...... 24
4.2. Power Interface ................................. 25
4.3. Energy Object Identification and Context ........ 25
4.4. Energy Object Relationships ..................... 27
4.5. Energy Monitoring ............................... 33
<Claise, et. Al> Expires August, 2013 [Page 3]
Internet-Draft <EMAN Framework> February 2013
4.6. Control ......................................... 35
4.7. Energy Management Reference Model................ 39
4.8 Using Device Relationships to Create Topologies... 40
4.9 Generalized Relationship Model.................... 47
5. Energy Management Information Model .................. 50
6. Example Topologies ................................... 56
6.1 Example I: Simple Device with one Source.......... 56
6.2 Example II: Multiple Inlets....................... 57
6.3 Example III: Multiple Sources..................... 58
7. Relationship with Other Standards .................... 58
8. Security Considerations .............................. 59
9. IANA Considerations .................................. 61
10. Acknowledgments ..................................... 61
11. References .......................................... 61
Normative References.................................. 61
Informative References................................ 62
OPEN ISSUES:
Are Tracked via Issue Tracker. See
https://trac.tools.ietf.org/wg/eman/trac/report/1
<Claise, et. Al> Expires August, 2013 [Page 4]
Internet-Draft <EMAN Framework> February 2013
1. Introduction
Network management is often divided into the five main areas
defined in the ISO Telecommunications Management Network
model: Fault, Configuration, Accounting, Performance, and
Security Management (FCAPS) [X.700]. Not covered by this
management model is Energy Management, which is now becoming a
critical area of concern worldwide as seen in [ISO50001].
This document defines a framework for providing Energy
Management for devices within or connected to communication
networks. The framework describes how to identify, classify
and provide context for such devices.
The devices, or components of these devices, can then be
monitored and controlled. Monitoring includes power, energy,
demand, and attributes of power. Control for energy can be
achieved by setting devices or components power state. If a
device contains batteries, these can be also be monitored and
controlled.
The most basic example of Energy Management is a single device
reporting information about itself. However, in many cases,
energy is not measured by the device itself, but by a meter
located upstream in the power distribution tree. An example
is a power distribution unit (PDU) that measures energy
supplied to attached devices and reports this to an energy
management system. Therefore, devices and their components
are recognized as having relationships to other devices or
components in the network from the point of view of energy
management. There are further relationships between devices
and components, respectively, including aggregation
relationship, metering relationship, power source
relationship, and proxy relationship.
Energy Management Documents Overview
The EMAN standard provides a set of specifications for Energy
Management. This document specifies the framework, per the
Energy Management requirements specified in [EMAN-REQ].
The applicability statement document [EMAN-AS] provides a list
of use cases, a cross-reference between existing standards and
the EMAN standard, and shows how this framework relates to
other frameworks.
<Claise, et. Al> Expires August, 2013 [Page 5]
Internet-Draft <EMAN Framework> February 2013
The Energy Object Context MIB [EMAN-OBJECT-MIB] specifies
objects for addressing Energy Object Identification,
classification, context information, and relationships from
the point of view of Energy Management.
The Power and Energy Monitoring MIB [EMAN-MON-MIB] contains
objects for monitoring of Power, Energy, Demand, Power
Attributes and Power States.
Further, the battery monitoring MIB [EMAN-BATTERY-MIB] defines
managed objects that provide information on the status of
batteries in managed devices.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described
in RFC 2119 [RFC2119].
Some terms have a NOTE that is not part of the
definition itself, but is present to take into
account differences between terminologies of
different standards organizations or to add a
comment to help clarify the definition.
Device
A piece of electrical or non-electrical equipment.
Reference: Adapted from [IEEE100]
Component
A part of an electrical or non-electrical equipment
(Device).
Reference: Adapted from [ITU-T-M-3400]
Energy Management
Energy Management is a set of functions for
measuring, modeling, planning, and optimizing
networks to ensure that the network elements and
attached devices use energy efficiently and is
<Claise, et. Al> Expires August, 2013 [Page 6]
Internet-Draft <EMAN Framework> February 2013
appropriate for the nature of the application and
the cost constraints of the organization.
Reference: Adapted from [ITU-T-M-3400]
NOTES:
1. Energy management refers to the activities,
methods, procedures and tools that pertain to
measuring, modeling, planning, controlling and
optimizing the use of energy in networked
systems [NMF].
2. Energy Management is a management domain which
is congruent to any of FCAPS areas of
management in the ISO/OSI Network Management
Model [TMN]. Energy Management for
communication networks and attached devices is
a subset or part of an organization's greater
Energy Management Policies.
Energy Management System (EnMS)
An Energy Management System is a combination of
hardware and software used to administer a
network with the primary purpose being Energy
Management.
Reference: Adapted from [1037C]
NOTES:
1. An Energy Management System according to
[ISO50001] (ISO-EnMS) is a set of systems or
procedures upon which organizations can develop
and implement an energy policy, set targets,
action plans and take into account legal
requirements related to energy use. An ISO-
EnMS allows organizations to improve energy
performance and demonstrate conformity to
requirements, standards, and/or legal
requirements.
2. Example ISO-EnMS: Company A defines a set of
policies and procedures indicating there should
exist multiple computerized systems that will
poll energy from their meters and pricing /
source data from their local utility. Company A
specifies that their CFO should collect
information and summarize it quarterly to be
sent to an accounting firm to produce carbon
<Claise, et. Al> Expires August, 2013 [Page 7]
Internet-Draft <EMAN Framework> February 2013
accounting reporting as required by their local
government.
3. For the purposes of EMAN, the definition from
[1037C] is the preferred meaning of an Energy
Management System (EnMS). The definition from
[ISO50001] can be referred to as ISO Energy
Management System (ISO-EnMS).
Energy
That which does work or is capable of doing work.
As used by electric utilities, it is generally a
reference to electrical energy and is measured in
kilo-watt hours (kWh).
Reference: [IEEE100]
NOTES
1. Energy is the capacity of a system to produce
external activity or perform work [ISO50001]
Power
The time rate at which energy is emitted,
transferred, or received; usually expressed in
watts (joules per second).
Reference: [IEEE100]
Demand
The average value of power or a related quantity
over a specified interval of time. Note: Demand
is expressed in kilowatts, kilovolt-amperes,
kilovars, or other suitable units.
Reference: [IEEE100]
NOTES:
1. For EMAN we use kilowatts.
Power Attributes
Measurements of the electrical current, voltage, phase and
frequencies at a given point in an electrical power system.
<Claise, et. Al> Expires August, 2013 [Page 8]
Internet-Draft <EMAN Framework> February 2013
Reference: Adapted from [IEC60050]
NOTES:
1. Power Characteristics is not intended to be judgmental
with respect to a reference or technical value and are
independent of any usage context.
Power Quality
Characteristics of the electric current, voltage, phase and
frequencies at a given point in an electric power system,
evaluated against a set of reference technical parameters.
These parameters might, in some cases, relate to the
compatibility between electricity supplied in an electric
power system and the loads connected to that electric power
system.
Reference: [IEC60050]
NOTES:
1. Electrical characteristics representing power quality
information are typically required by customer facility
energy management systems. It is not intended to satisfy the
detailed requirements of power quality monitoring. Standards
typically also give ranges of allowed values; the
information attributes are the raw measurements, not the
"yes/no" determination by the various standards.
Reference: [ASHRAE-201]
Electrical Equipment
A general term including materials, fittings,
devices, appliances, fixtures, apparatus,
machines, etc., used as a part of, or in
connection with, an electric installation.
Reference: [IEEE100]
Non-Electrical Equipment (Mechanical Equipment)
A general term including materials, fittings,
devices appliances, fixtures, apparatus,
<Claise, et. Al> Expires August, 2013 [Page 9]
Internet-Draft <EMAN Framework> February 2013
machines, etc., used as a part of, or in
connection with, non-electrical power
installations.
Reference: Adapted from [IEEE100]
Energy Object
An Energy Object (EO) is a piece of equipment
that is part of or attached to a communications
network that is monitored, controlled, or aids in
the management of another device for Energy
Management.
Electrical Energy Object
An Electrical Energy Object (EEO) is an Energy
Object that is a piece of Electrical Equipment
Non-Electrical Energy Object
A Non-Electrical Energy Object (NEEO) an Energy
Object that is a piece of Non-Electrical
Equipment.
Energy Monitoring
Energy Monitoring is a part of Energy Management
that deals with collecting or reading information
from Energy Objects to aid in Energy Management.
Energy Control
Energy Control is a part of Energy Management
that deals with directing influence over Energy
Objects.
Provide Energy:
An Energy Object "provides" energy to another Energy Object
if there is an energy flow from this Energy Object to the
other one.
<Claise, et. Al> Expires August, 2013 [Page 10]
Internet-Draft <EMAN Framework> February 2013
Receive Energy:
An Energy Object "receives" energy from another Energy
Object if there is an energy flow from the other Energy
Object to this one.
Power Interface
A Power Interface (or simply interface) is an
interconnection among devices or components where energy
can be provided, received, or both.
Power Inlet
A Power Inlet (or simply inlet) is an interface at which a
device or component receives energy from another device or
component.
Power Outlet
A Power Outlet (or simply outlet) is an interface at which
a device or component provides energy to another device or
component.
Energy Management Domain
An Energy Management Domain is a set of Energy Objects that
is considered one unit of management.
Energy Object Identification
Energy Object Identification is a set of
attributes that enable an Energy Object to be
universally unique or linked to other systems.
Energy Object Context
Energy Object Context is a set of attributes that
allow an Energy Management System to classify
the Energy Object within an organization.
<Claise, et. Al> Expires August, 2013 [Page 11]
Internet-Draft <EMAN Framework> February 2013
Energy Object Relationship
An Energy Object Relationship is an association among
Energy Objects
NOTES
1. Relationships can be named and could include
Aggregation, Metering, Power Source, and Proxy.
Reference: Adapted from [CHEN]
Aggregation Relationship
An Aggregation Relationship is an Energy Object
Relationship where one Energy Object aggregates Energy
Management information of one or more other Energy Objects.
The aggregating Energy Object has an Aggregation
Relationship with each of the other Energy Objects.
Metering Relationship
A Metering Relationship is an Energy Object Relationship
where one Energy Object measures power, energy, demand or
power attributes of one or more other Energy Objects. The
measuring Energy Object has a Metering Relationship with
each of the measured objects.
Power Source Relationship
A Power Source Relationship is an Energy Object
Relationship where one Energy Object provides power to one
or more Energy Objects. These Energy Objects are referred
to as having a Power Source Relationship.
Proxy Relationship
A Proxy Relationship is an Energy Object Relationship where
one Energy Object provides the Energy Management
capabilities on behalf of one or more other Energy Objects.
These Energy Objects are referred to as having a Proxy
Relationship.
<Claise, et. Al> Expires August, 2013 [Page 12]
Internet-Draft <EMAN Framework> February 2013
Energy Object Parent
An Energy Object Parent is an Energy Object that
participates in an Energy Object Relationship and
is considered as providing the capabilities in
the relationship.
Energy Object Child
An Energy Object Child is an Energy Object that
participates in an Energy Object Relationships
and is considered as receiving the capabilities
in the relationship.
Power State
A Power State is a condition or mode of a device
that broadly characterizes its capabilities,
power consumption, and responsiveness to input.
Reference: Adapted from [IEEE1621]
Power State Set
A collection of Power States that comprise a
named or logical grouping of control is a Power
State Set.
Nameplate Power
The Nameplate Power is the nominal Power of a
device as specified by the device manufacturer.
3. Issues Specific to Energy Management
With Energy Management, there exists a wide variety of devices
that may be contained in the same deployments as a
communication network but comprise a separate facility, home,
or power distribution network.
<Claise, et. Al> Expires August, 2013 [Page 13]
Internet-Draft <EMAN Framework> February 2013
Target devices for Energy Management are all Energy Objects
that can directly or indirectly be monitored or controlled by
an Energy Management System (EnMS) using the Internet
protocol, for example:
- Simple electrical appliances / fixtures
- Hosts, such as a PC, a server, or a printer
- switches, routers, base stations, and other network
equipment and middleboxes
- A component within devices, such as a battery inside a
PC, a line card inside a switch, etc...
- Power over Ethernet (PoE) endpoints
- Power Distribution Units (PDU)
- Protocol gateway devices for Building Management Systems
(BMS)
- Electrical meters
- Sensor controllers with subtended sensors
There may also exist varying protocols deployed among these
power distributions and communication networks.
An Energy Management framework should also apply to these
types of separate networks as they connect and interact with a
communications network.
This section explains special issues of Energy Management
particularly concerning power supply, Power, and Energy
metering, and the reporting of Power States.
Energy Management has particular challenges in that a power
distribution network is used for the supply of energy to
various devices and components, while a separate communication
network is typically used to monitor and control the power
distribution network.
To illustrate the issues we start with a simple and basic
scenario where a single powered device receives Energy and
reports energy-related information about itself to an Energy
Management System (EnMS), see Figure 1
+--------------------------+
| Energy Management System |
+--------------------------+
^ ^
monitoring | | control
v v
<Claise, et. Al> Expires August, 2013 [Page 14]
Internet-Draft <EMAN Framework> February 2013
+-----------------+
| powered device |
+-----------------+
Figure 1: Basic energy management scenario
The powered device may have local energy control mechanisms,
for example putting itself into a sleep mode when appropriate,
and it may receive energy control commands for similar
purposes from the EnMS. Information reported from a powered
device to the EnMS includes at least the Power State of the
powered device (on, sleep, off, etc.).
This and similar cases are well understood and likely to
become very common for Energy Management. They can be handled
with well established and standardized management procedures.
The only missing components today are standardized information
and data models for reporting and configuration, such as, for
example, energy-specific MIB modules [RFC2578] and YANG
modules [RFC6020].
However, the nature of energy supply and use introduces some
issues that are special to Energy Management. The following
subsections address these issues and illustrate them by
extending the basic scenario in Figure 1.
WRT to Energy management there nothing new for faults, config,
performance or security management. We can re-use those
aspects of network management for an EnMS. But when there are
aspects specific to EM then this framework adds them. For
example with faults we can re-use rmon or snmp traps. For
security existing means like SNMPv3 security can be used.
3.1. Power Supply
A powered device may supply itself with power. Sensors, for
example, commonly have batteries or harvest Energy. However,
most powered devices that are managed by an EnMS receive
external power.
While many devices receive Power from unmanaged supply
systems, the number of manageable power supply devices is
increasing.
In datacenters, for example, many Power Distribution Units
(PDUs) allow the EnMS to switch power individually for each
socket and also to measure the provided Power. This is an
<Claise, et. Al> Expires August, 2013 [Page 15]
Internet-Draft <EMAN Framework> February 2013
action much different from many other network management
tasks: In such and similar cases, switching power supply for a
powered device or monitoring its power is not done by
communicating with the actual powered device itself, but with
an external device (in this case, the PDU
Consequently, a standard for Energy Management must not just
cover the powered devices that provide services for users, but
also the power supply devices (which are powered devices as
well) that monitor or control the power supply for other
powered devices.
A simple device such as a light bulb can be switched on or off
only by switching its power supply. More complex devices may
have the ability to switch off themselves or to bring
themselves to states in which they consume very little power.
For these devices as well, it is desirable to monitor and
control their power supply.
This extends the basic scenario from Figure 1 by a power
supply device, see Figure 2.
+-----------------------------------------+
| energy management system |
+-----------------------------------------+
^ ^ ^ ^
monitoring | | control monitoring | | control
v v v v
+--------------+ +-----------------+
| power supply |########| powered device |
+--------------+ +-----------------+
######## power supply line
Figure 2: Power Supply
The power supply device can be as simple as a plain power
switch. It may offer interfaces to the EnMS to monitor and to
control the status of its power outlets, as with PDUs and
Power over Ethernet (PoE) [IEEE-802.3at] switches.
The relationship between supply devices and the powered
devices they serve creates several problems for managing power
supply:
o Identification of corresponding devices
* A given powered device may be need to identify the
supplying power supply device.
<Claise, et. Al> Expires August, 2013 [Page 16]
Internet-Draft <EMAN Framework> February 2013
* A given power supply device may need to identify the
corresponding supplied powered device(s).
o Aggregation of monitoring and control for multiple
powered devices
* A power supply device may supply multiple powered
devices with a single power supply line.
o Coordination of power control for devices with multiple
power inlets
* A powered device may receive power via multiple power
lines controlled by the same or different power
supply devices.
Identification of Power Supply and Powered Devices
When a power supply device controls or monitors power supply
at one of its power outlets, the effect on other devices is
not always clear without knowledge about wiring of power
lines. The same holds for monitoring. The power supplying
device can report that a particular socket is powered, and it
may even be able to measure power and conclude that there is a
consumer drawing power at that socket, but it may not know
which powered device(s)receives the provided power.
In many cases it is obvious which other device is supplied by
a certain outlet, but this always requires additional
(reliable) information about power line wiring. Without
knowing which device(s) are powered via a certain outlet,
monitoring data are of limited value and the consequences of
switching power on or off may be hard to predict.
Even in well organized operations, powered devices' power
cords can be plugged into the wrong socket, or wiring plans
changed without updating the EnMS accordingly.
For reliable monitoring and control of power supply devices,
additional information is needed to identify the device(s)
that receive power provided at a particular monitored and
controlled socket.
This problem also occurs in the opposite direction. If power
supply control or monitoring for a certain device is needed,
then the supplying power supply device has to be identified.
To conduct Energy Management tasks for both power supply
devices and other powered devices, sufficiently unique
identities are needed, and knowledge of their power supply
relationship is required.
<Claise, et. Al> Expires August, 2013 [Page 17]
Internet-Draft <EMAN Framework> February 2013
Multiples Devices Supplied by a Single Power Line
The second fundamental problem is the aggregation of
monitoring and control that occurs when multiple powered
devices are supplied by a single power supply line. It is
often required for the EnMS to discover the full list of
powered devices connected to a power supply line, as in Figure
3.
+---------------------------------------+
| energy management system |
+---------------------------------------+
^ ^ ^ ^
monitoring | | control monitoring | | control
v v v v
+--------+ +------------------+
| power |########| powered device 1 |
| supply | # +------------------+-+
+--------+ #######| powered device 2 |
# +------------------+-+
#######| powered device 3 |
+------------------+
Figure 3: Multiple Powered Devices Supplied
by Single Power Line
With this list, the single status value has clear meaning and
is the sum of all powered devices. Control functions are
limited by the fact that supply for the concerned devices can
only be switched on or off for all of them at once.
Individual control at the supply is not possible.
If the full list of devices powered by a single supply line is
not known by the controlling power supply device, then control
of power supply is problematic, because the consequences of
control actions can only be partially known.
Multiple Power Supply for a Single Powered Device
The third problem arises from the fact that there are devices
with multiple power supplies. Some have this for redundancy
of power supply, some for just making internal power
converters (for example, from AC mains power to DC internal
<Claise, et. Al> Expires August, 2013 [Page 18]
Internet-Draft <EMAN Framework> February 2013
power) redundant, and some because the capacity of a single
supply line is insufficient.
+----------------------------------------------+
| energy management system |
+----------------------------------------------+
^ ^ ^ ^ ^ ^
mon. | | ctrl. mon. | | ctrl. mon. | | ctrl.
v v v v v v
+----------+ +----------+ +----------+
| power |######| powered |######| power |
| supply 1 |######| device | | supply 2 |
+----------+ +----------+ +----------+
Figure 4: Multiple Power Supply for Single Powered Device
The example in Figure 4 does not necessarily show a real world
scenario, but it shows the two cases to consider:
o multiple power supply lines between a single power
supply
device and a powered device
o different power supply devices supplying a single
powered device
In any such case there may be a need to identify the supplying
power supply device individually for each power inlet of a
powered device.
Without this information, monitoring and control of power
supply for the powered device may be limited.
Bidirectional Power Interfaces
Some power technologies (mostly low power DC) allow power to
be delivered bi-directionally. In the example, energy stored
in batteries on one device can be delivered back to a power
hub which redirects the power to another device. In this
situation, the interface can function as both an inlet and
outlet (at different times).
A Power Interface can model a power inlet or a power outlet,
depending on the conditions. Information of interest Power
Interfaces include the power direction, as well as the energy
received, provided, and the net result.
<Claise, et. Al> Expires August, 2013 [Page 19]
Internet-Draft <EMAN Framework> February 2013
Relevance of Power Supply Issues
In some scenarios, the problems with power supply do not exist
or can be sufficiently solved. With Power over Ethernet (PoE)
[IEEE-802.3at], there is always a one-to-one relationship
between a Power Sourcing Equipment (PSE) and a Powered Device
(PD). Also, the Ethernet link on the line used for powering
can be used to identify the PD and in many cases also the PSE.
For supply of AC mains power, the three problems described
above cannot be solved in general. There is no commonly
available protocol or automatic mechanism for identifying
endpoints of a power line.
And, AC power lines support supplying multiple powered devices
with a single line and commonly do.
Remote Power Supply Control
There are three ways for an energy management system to change
the Power State of powered devices. First is for the EnMS to
provide policy or other useful information (like the
electricity price) to the powered device for it to use in
determining its Power State. The second is sending the
powered devices a command to switch to another Power State.
The third is to utilize an upstream device (to the powered
device) that has capabilities to switch on and off power at
its outlet.
Some devices do not have capabilities for receiving commands
or changing their Power States by themselves. Such Energy
Objects may be controlled by switching on and off the power
supply for them and so have particular need for the third
method.
In Figure 4, the power supply can switch on and off power at
its power outlet and thereby switch on and off power supply
for the connected powered device.
3.2. Power and Energy Measurement
Some devices include hardware to directly measure their Power
and Energy consumption. However, most common networked
devices do not provide an interface that gives access to
Energy and Power measurements. Hardware instrumentation for
<Claise, et. Al> Expires August, 2013 [Page 20]
Internet-Draft <EMAN Framework> February 2013
this kind of measurements is typically not in place and adding
it incurs an additional cost.
With the increasing cost of Energy and the growing importance
of Energy Monitoring, it is expected that in future more
devices will include instrumentation for power and energy
measurements, but this may take quite some time.
Local Estimates
One solution to this problem is for the powered device to
estimate its own Power and consumed Energy. For many Energy
Management tasks, getting an estimate is much better than not
getting any information at all. Estimates can be based on
actual measured activity level of a device or it can just
depend on the power state (on, sleep, off, etc.).
An advantage of estimates is that they can be realized locally
and with much lower cost than hardware instrumentation. Local
estimates can be dealt with in traditional ways. They don't
need an extension of the basic scenarios above. However, the
powered device needs an energy model of itself to make
estimates.
Management System Estimates
Another approach to the lack of instrumentation is estimation
by the EnMS. The EnMS can estimate Power based on basic
information on the powered device, such as the type of device,
or also its brand/model and functional characteristics.
Energy estimates can combine the typical power level by Power
State with reported data about the Power State.
If the EnMS has a detailed energy model of the device, it can
produce better estimates including the actual power state and
actual activity level of the device. Such information can be
obtained by monitoring the device with conventional means of
performance monitoring.
3.3. Reporting Sleep and Off States
Low power modes pose special challenges for energy reporting
because they may preclude a device from listening to and
responding to network requests. Devices may still be able to
reliably track energy use in these modes, as power levels are
<Claise, et. Al> Expires August, 2013 [Page 21]
Internet-Draft <EMAN Framework> February 2013
usually static and internal clocks can track elapsed time in
these modes.
Some devices have out-of-band or proxy abilities to respond to
network requests in low-power modes. Others could use proxy
abilities in an energy management protocol to improve this
reporting, particularly if the powered device sends out
notifications of power state changes.
3.4. Device and Device Components
While the typical focus of energy management is entire powered
devices, sometimes it is desirable to manage individual
components of devices, such as line cards, fans, disks, etc.
This framework uses a much simpler model for components than
for entire devices. The concept of Power Interfaces is not
used between a device and its contained components. Reporting
of energy-related quantities for individual components is
limited to the most important ones. Simplifications for
components in this framework include
o identifying components like devices but without
distinct context information,
o reporting a containment relationship to the containing
device,
o inheriting all context information from the containing
device,
o not modeling power interfaces and power lines between
the a component and its containing device or other
components,
o only reporting real power and energy values for
components,
o supporting power state monitoring and control for
components.
In rare cases where there is a need to model components of a
device in more detail, components of a device can be modeled
as an individual device. Then all considerations for devices
also apply to these components. The overhead of this model is
higher and it should be applied only when needed. If used, it
is not necessarily visible whether or not a set of components
belongs to a single device, but for energy management purposes
this might not be of high relevance.
<Claise, et. Al> Expires August, 2013 [Page 22]
Internet-Draft <EMAN Framework> February 2013
3.5. Non-Electrical Equipment
The primary focus of this framework is for the management of
Electrical Equipment. Some Non-Electrical Equipment may be
connected to a communication networks and could have their
energy managed if normalized to the electrical units for power
and energy.
Some examples of Non-Electrical Equipment that may be
connected to a communication network are:
1) A controller for compressed air. The controller is
electrical only for its network connection. The controller
is fueled by natural gas and produces compressed air. The
energy transferred via compressed air is distributed to
devices on a factory floor via a Power Interface: tools
(drills, screwdrivers, assembly line conveyor belts). The
energy measured is non-electrical (compressed air).
2) A controller for steam. The controller is electrical for its
network attachment but it burns tallow and produces steam to
subtended boilers. The energy is non-electrical (steam).
3) A controller or regulator for gas. The controller is
electrical for its network attachment but it has physical
non-electrical components for control. The energy is non-
electrical (BTU).
4. Energy Management Abstraction
Energy Management can be organized into areas of concern that
include:
- Energy Object Identification and Context - for modeling and
planning
- Energy Monitoring - for energy measurements
- Energy Control - for optimization
- Energy Procurement - for optimization of resources
While an EnMS may be a central point for corporate reporting,
cost, environmental impact, and regulatory compliance, Energy
Management in this framework excludes Energy procurement and
the environmental impact of energy use. As such the framework
does not include:
- Manufacturing costs of an Energy Object in currency or
environmental units
- Embedded carbon or environmental equivalences of an Energy
Object
<Claise, et. Al> Expires August, 2013 [Page 23]
Internet-Draft <EMAN Framework> February 2013
- Cost in currency or environmental impact to dismantle or
recycle an Energy Object
- Supply chain analysis of energy sources for Energy Object
deployment
- Conversion of the usage or production of energy to units
expressed from the source of that energy (such as the
greenhouse gas emissions associated with 1000kW from a diesel
source).
The next sections describe Energy Management organized into
the following areas:
- Energy Object and Energy Management Domain
- Energy Object Identification and Context
- Energy Object Relationships
- Energy Monitoring
- Energy Control
- Deployment Topologies
4.1. Energy Object and Energy Management Domain
A meter is a type of device and any device can perform
metering.
In building management, a meter refers to the meter provided
by the utility used for billing and measuring power to an
entire building or unit within a building. A sub-meter refers
to a customer or user installed meter that is not used by the
utility to bill but instead used to get readings from sub
portions of a building.
An Energy Management Domain can be any collection of devices
in a building but is recommended to map 1:1 with a metered or
sub-metered portion of the site. An Energy Object is part of
a single Energy Management Domain. The Energy Management
Domain MAY be configured on an Energy Object: the default
value is a zero-length string.
If all Energy Objects in the physical containment tree (see
ENTITY-MIB) are part of the same Energy Management Domain,
then it is safe to state that the Energy Object at the root of
that containment tree is in that Energy Management Domain.
An Energy Object Child may inherit the domain value from an
Energy Object Parent or the Energy Management Domain may be
configured directly in an Energy Object Child.
<Claise, et. Al> Expires August, 2013 [Page 24]
Internet-Draft <EMAN Framework> February 2013
4.2. Power Interface
There are some similarities between Power Interfaces and
network interfaces. A network interface can be used in
different modes, such as sending or receiving on an attached
line. The Power Interface can be receiving or providing
power.
Most Power Interfaces never change their mode, but as the mode
is simply a recognition of the current direction of
electricity flow, there is no barrier to a mode change.
A power interface can have capabilities for metering power and
other electric quantities at the shared power transmission
medium.
This capability is modeled by an association to a power meter.
In analogy to MAC addresses of network interfaces, a globally
unique identifier is assigned to each Power Interface.
Physically, a Power Interface can be located at an AC power
socket, an AC power cord attached to a device, an 8P8C (RJ45)
PoE socket, etc.
4.3. Energy Object Identification and Context
Energy Object Identification
A Universal Unique Identifier (UUID) [RFC4122] MUST be used to
uniquely and persistently identify an Energy Object. Ideally
the UUID should be used to distinguish the Energy Object among
all Energy Management Domains within the EnMS.
Every Energy Object SHOULD have a unique printable name within
the Energy Management Domain. Possible naming conventions
are: textual DNS name, MAC-address of the device, interface
ifName, or a text string uniquely identifying the Energy
Object. As an example, in the case of IP phones, the Energy
Object name can be the device's DNS name.
<Claise, et. Al> Expires August, 2013 [Page 25]
Internet-Draft <EMAN Framework> February 2013
Context in General
In order to aid in reporting and in differentiation between
Energy Objects, each Energy Object optionally contains
information establishing its business, site, or organizational
context within a deployment, i.e. the Energy Object Context.
Context: Importance
An Energy Object can provide an importance value in the range
of 1 to 100 to help rank a device's use or relative value to
the site. The importance range is from 1 (least important) to
100 (most important). The default importance value is 1.
For example: A typical office environment has several types of
phones, which can be rated according to their business impact.
A public desk phone has a lower importance (for example, 10)
than a business-critical emergency phone (for example, 100).
As another example: A company can consider that a PC and a
phone for a customer-service engineer is more important than a
PC and a phone for lobby use.
Although EnMS and administrators can establish their own
ranking, the following is a broad recommendation [CISC0-EW]:
. 90 to 100 Emergency response
. 80 to 90 Executive or business-critical
. 70 to 79 General or Average
. 60 to 69 Staff or support
. 40 to 59 Public or guest
. 1 to 39 Decorative or hospitality
Context: Keywords
An Energy Object can provide a set of keywords. These
keywords are a list of tags that can be used for grouping,
summary reporting within or between Energy Management Domains,
and for searching. All alphanumeric characters and symbols
(other than a comma), such as #, (, $, !, and &, are allowed.
Potential examples are: IT, lobby, HumanResources, Accounting,
StoreRoom, CustomerSpace, router, phone, floor2, or
SoftwareLab. There is no default value for a keyword.
Multiple keywords can be assigned to a device. White spaces
before and after the commas are excluded, as well as within a
<Claise, et. Al> Expires August, 2013 [Page 26]
Internet-Draft <EMAN Framework> February 2013
keyword itself. In such cases, the keywords are separated by
commas and no spaces between keywords are allowed. For
example, "HR,Bldg1,Private".
Context: Role
An Energy Object can provide a "role description" string that
indicates the purpose the Energy Object serves in the EnMS.
This could be a string describing the context the device
fulfills in deployment.
Administrators can define any naming scheme for the role of a
device. As guidance a two-word role that combines the service
the device provides along with type can be used [IPENERGY]
Example types of devices: Router, Switch, Light, Phone,
WorkStation, Server, Display, Kiosk, HVAC.
Example Services by Line of Business:
Line of Business Service
Education Student, Faculty, Administration,
Athletic
Finance Trader, Teller, Fulfillment
Manufacturing Assembly, Control, Shipping
Retail Advertising, Cashier
Support Helpdesk, Management
Medical Patient, Administration, Billing
Role as a two-word string: "Faculty Desktop", "Teller Phone",
"Shipping HVAC", "Advertising Display", "Helpdesk Kiosk",
"Administration Switch".
4.4. Energy Object Relationships
Two Energy Objects MAY establish an Energy Object
Relationship. Within a relationship one Energy Object becomes
an Energy Object Parent while the other becomes an Energy
Object Child.
The Power Source Relationship gives a view of wiring topology.
For example: a data center server receiving power from two
specific Power Interfaces from two different PDUs.
<Claise, et. Al> Expires August, 2013 [Page 27]
Internet-Draft <EMAN Framework> February 2013
Note: A power source relationship may or may not change as the
direction of power changes between two Energy Objects. The
relationship may remain to indicate the change of power
direction was unintended or an error condition.
The Metering Relationship gives the view of the metering
topology. Standalone meters can be placed anywhere in a power
distribution tree. For example, utility meters monitor and
report accumulated power consumption of the entire building.
Logically, the metering topology overlaps with the wiring
topology, as meters are connected to the wiring topology. A
typical example is meters that clamp onto the existing wiring.
The Proxy Relationship allows software objects to be inserted
into the wiring or metering topology to aid in management
(monitoring and/or control).
In many situations, the wiring, metering, and management
topologies overlap. For example, a Power-over-Ethernet (PoE)
device (such as an IP phone or an access point) is attached to
a switch port. The switch port is the source of power for the
attached device, so the Energy Object Parent is the switch
port, which is a Power Interface, and the Energy Object Child
is the device attached to the switch. This Energy Object
Parent (the switch) has three Energy Object Relations with
this Energy Object Child (the remote Energy Object): Power
Source Relationship, Metering Relationship, and Proxy
Relationship.
However, the three topologies (wiring, metering, and
management) don't always overlap. For example, when a
protocol gateways device for Building Management Systems (BMS)
controls subtended devices, which themselves receive Power
from PDUs or wall sockets.
Note: The Aggregation Relationship is slightly different
compared to the other relationships (Power Source, Metering,
and Proxy Relationships) as this refers more to a management
function.
The communication between the parent and child for monitoring
or collection of power data is left to the device
manufacturer. For example: A parent switch may use LLDP to
communicate with a connected child, and a parent lighting
controller may use BACNET to communicate with child lighting
devices.
<Claise, et. Al> Expires August, 2013 [Page 28]
Internet-Draft <EMAN Framework> February 2013
The Energy Object Child SHOULD keep track of its Energy Object
Parent(s) along with the Energy Object Relationships type(s).
The Energy Object Parent SHOULD keep track of its Energy
Object Child(ren), along with the Energy Object Relationships
type(s).
Energy Object Children Discovery
There are multiple ways that the Energy Object Parent can
discover its Energy Object Children: :
. In case of PoE, the Energy Object Parent automatically
discovers an Energy Object Child when the Child requests
power.
. The Energy Object Parent and Children may run the Link
Layer Discovery Protocol [LLDP], or any other discovery
protocol, such as Cisco Discovery Protocol (CDP). The
Energy Object Parent might even support the LLDP-MED MIB
[LLDP-MED-MIB], which returns extra information on the
Energy Object Children.
. The Energy Object Parent may reside on a network
connected to a facilities gateway. A typical example is
a converged building gateway, monitoring several other
devices in the building, and serving as a proxy between
SNMP and a protocol such as BACNET.
. A different protocol between the Energy Object Parent and
the Energy Object Children. Note that the communication
specifications between the Energy Object Parent and
Children is out of the scope of this document.
However, in some situations, it is not possible to discover
the Energy Object Relationships, and they must be set
manually. For example, in today' network, an administrator
must assign the connected Energy Object to a specific PDU
Power Interface, with no means of discovery other than that
manual connection.
When an Energy Object Parent is a Proxy, the Energy Object
Parent SHOULD enumerate the capabilities it is providing for
the Energy Object Child. The child would express that it
wants its parent to proxy capabilities such as, energy
reporting, power state configurations, non physical wake
capabilities (such as WoL)), or any combination of
capabilities.
<Claise, et. Al> Expires August, 2013 [Page 29]
Internet-Draft <EMAN Framework> February 2013
Energy Object Relationship Conventions and Guidelines
This Energy Management framework does not impose many "MUST"
rules related to Energy Object Relationships. There are always
corner cases that could be excluded with too strict
specifications of relationships. However, this Energy
Management framework proposes a series of guidelines,
indicated with "SHOULD" and "MAY".
Aggregation
Aggregation relationships are intended to identify when one
device is used to accumulate values from other devices.
Typically this is for energy or power values among devices and
not for Components or Power Interfaces on the same device.
The intent of Aggregation relationships is to indicate when
one device is providing aggregate values for a set of other
devices when it is not obvious form the power source or simple
containment within a device.
Establishing aggregation relationships within the same device
would make modeling more complex and the aggregated values can
be implied form the use of Power Inlets, outlet and Energy
Object value son the same device.
Additionally since an EnMS is naturally a point of aggregation
it is not necessary to model aggregation for an EnMS(s).
Aggregation SHOULD be used for power and energy. It MAY be
used for aggregation of other values from the information
model for example but the rules and logical ability to
aggregated each attribute is out of scope for this document.
- A Device SHOULD NOT establish an Aggregation Relationship
with a Component.
- A Device SHOULD NOT establish an Aggregation Relationship
with the Power Interfaces contained on the same device.
- A Device SHOULD NOT establish an Aggregation Relationship
with the an EnMS.
- Aggregators SHOULD log or provide notification in the case
of errors or missing values while performing aggregation.
Power Source
<Claise, et. Al> Expires August, 2013 [Page 30]
Internet-Draft <EMAN Framework> February 2013
Power Source relationships are intended to identify the
connections between Power Interfaces. This is analogous to a
Layer 2 connection in networking devices (a one hop
connection).
The preferred modeling would be for Power Interfaces to
participate in Power Source Relationships.
It may happen that the some Energy Objects may not have the
capability to model Power Interfaces. Therefore, it may
happen that a Power Source Relationship is established between
two Energy Objects or two non-connected Power Interfaces.
While strictly speaking Components and Power Interfaces on the
same device do provide or receive energy from each other the
Power Source relationship is intended to show energy transfer
between Devices. Therefore relationship is implied on the same
Device.
- An Energy Object SHOULD NOT establish a Power Source
Relationship with a Component.
- A Power Source Relationship SHOULD be established with next
known Power Interface in the wiring topology.
o The next known Power Interface in the wiring topology
would be the next device implementing the framework. In
some cases the domain of devices under management may
include some devices that do not implement the
framework As such the Power Source relationship can be
established with the next device in the topology that
implements the framework and logically shows the Power
Source of the device.
- Transitive Power Source relationships SHOULD NOT be
established. For examples if an Energy Object A has a Power
Source Relationship "Poweredby" with the Energy Object B,
and if the Energy Object B has a Power Source Relationship
"Poweredby" with the Energy Object C, then the Energy Object
A SHOULD NOT have a Power Source Relationship "PoweredBby"
the Energy Object C.
Metering Relationship
Metering Relationships are intended to show when one Device is
measuring the power or energy at a point in a power
distribution system. Since one point of a power distribution
system may cover many Devices with a complex wiring topology,
this relationship type can be seen as an arbitrary set.
<Claise, et. Al> Expires August, 2013 [Page 31]
Internet-Draft <EMAN Framework> February 2013
Additionally, Devices may include metering hardware for
components and Power Interfaces or for the entire Device.
For example some PDU's may have the ability to measure Power
for each Power Interface (metered by outlet). Others may only
be able to control power at each Power Interface but only
measure Power at the Power Inlet and a total for all Power
Interfaces (metered by device).
In such cases a Device SHOULD be modeled as an Energy Object
that meters all of its Power Outlets and each Power Outlet MAY
be metered by the Energy Object representing the Device.
- A Meter Relationship MAY be established with any other
Energy Object, Component, or Power Interface.
- Transitive Meter relationships MAY be used.
- When there is a series of meters for one Energy Object, the
Energy Object MAY establish a relationship with one or more
of the meters.
Proxy
A Proxy relationship is intended to show when one Device is
providing the Energy Object capabilities for another Device
typically for protocol translations. Strictly speaking a a
Component of a Device may provide the Energy Object
capabilities for that Device (and vice versa) this
relationship is intended to model relationships between
Devices.
- A Proxy relationship SHOULD be limited when possible to
Energy Objects of different Devices.
Energy Objects Relationship Extensions
This framework for Energy Management, is based on four Energy
Objects Relationships: Aggregation Relationship, Metering
Relationship, Power Source Relationship, and Proxy
Relationship.
This framework is defined with possible extension of new
Energy Objects Relationships in mind. For example, a Power
Distribution Unit (PDU) that allows physical entities like
outlets to be "ganged" together as a logical entity for
simplified management purposes, could be modeled with a future
extension based on "gang relationship", whose semantic would
specify the Energy Objects grouping.
<Claise, et. Al> Expires August, 2013 [Page 32]
Internet-Draft <EMAN Framework> February 2013
4.5. Energy Monitoring
For the purposes of this framework energy will be limited to
electrical energy in watt hours. Other forms of Energy
Objects that use or produce non-electrical energy may be part
of an Energy Management Domain (See Section 3.5) but MUST
provide information converted to and expressed in watt hours.
An analogy for understanding power versus energy measurements
can be made to speed and distance in automobiles. Just as a
speedometer indicates the rate of change of distance, a power
meter indicates the rate of transfer of energy. The odometer
in an automobile measures the cumulative distance traveled and
an energy meter indicates the accumulate energy transferred.
So a less formal statement of the analogy is that power meters
measures "speed" while energy meters measure "distance".
Each Energy Object will have information that describes power
information, along with how that measurement was obtained or
derived (actual measurement, estimated, or presumed). For
Energy Objects that can report actual power readings, an
optional energy measurement can be provided.
Optionally, an Energy Object can further describe the Power
information with Power Quality information reflecting the
electrical characteristics of the measurement.
Optionally, an Energy Object that can report actual power
readings can have energy meters that provide the energy used,
produced, and net energy in kWh. These values are energy
meters that accumulate the power readings. If energy values
are returned then the three energy meters must be provided
along with a description of accuracy.
Optionally, an Energy Object can provide demand information
over time.
Power Measurement
A power measurement MUST be qualified with the units,
magnitude, direction of power flow, and SHOULD be qualified by
what means the measurement was made (ex: Root Mean Square
versus Nameplate).
<Claise, et. Al> Expires August, 2013 [Page 33]
Internet-Draft <EMAN Framework> February 2013
In addition, the Energy Object should describe how it intends
to measure power as one of consumer, producer or meter of
usage. Given the intent, readings can be summarized or
analyzed by an EnMS. For example metered usage reported by a
meter and consumption usage reported by a device connected to
that meter may naturally measure the same usage. With the two
measurements identified by intent a proper summarization can
be made by an EnMS.
Power measurement magnitude should conform to the IEC 61850
definition of unit multiplier for the SI (System
International) units of measure. Measured values are
represented in SI units obtained by BaseValue * (10 ^ Scale).
For example, if current power usage of an Energy Object is 3,
it could be 3 W, 3 mW, 3 KW, or 3 MW, depending on the value
of the scaling factor. 3W implies that the BaseValue is 3 and
Scale = 0, whereas 3mW implies BaseValue = 3 and ScaleFactor =
-3.
Electricity is usually billed in kilowatt-hours (not
megajoules, the SI units). Similarly, battery charge is often
measured as miliamperes-hour (mAh) instead of the SI unit
coulomb. The units used in this framework are: W, A, Wh, Ah,
V.
In addition to knowing the usage and magnitude, it is useful
to know how an Energy Object usage measurement was obtained:
. Whether the measurements were made at the device itself or
from a remote source.
. Description of the method that was used to measure the
power and whether this method can distinguish actual or
estimated values.
An EnMS can use this information to account for the accuracy
and nature of the reading between different implementations.
The EnMS can use the Nameplate Power for provisioning,
capacity planning and potentially billing.
6.5.2 Optional Power Attributes
Given a power measurement, it may be desirable to know
additional power attributes associated with that measurement.
<Claise, et. Al> Expires August, 2013 [Page 34]
Internet-Draft <EMAN Framework> February 2013
Optional Power Quality
The information model should adhere to the IEC 61850 7-2
standard for describing AC measurements.
Optional Demand
It is well known in commercial electrical utility rates that
demand is part of the calculation for billing. The highest
peak demand measured over a time horizon, such as 1 month or 1
year, is often the basis for charges. A single window of time
of high usage can penalize the consumer with higher energy
consumption charges. However, it is relevant to measure the
demand only when there are actual power measurements from an
Energy Object, and not when the power measurement is assumed
or predicted.
Optional Battery
Some Energy Objects may use batteries for storing energy and
for receiving power supply. These Energy Objects should
report their current power supply (battery, power line, etc.)
and the battery status for each contained battery. Battery-
specific information to be reported should include the number
of batteries contained in the device and per battery the state
information as defined in [EMAN-REQ].
Beyond that a device containing a battery should be able to
generate alarms when the battery charge falls below a given
threshold and when the battery needs to be replaced.
4.6. Control
An Energy Object can be controlled by setting it to a specific
Power State. An Object implements a set of Power States
consisting of at least two states, an on state and an off
state.
A Power State is an interface by which an Energy Object can be
controlled. Each Energy Object should indicate the set of
Power States that it implements. Well known Power States /
Sets should be registered with IANA.
<Claise, et. Al> Expires August, 2013 [Page 35]
Internet-Draft <EMAN Framework> February 2013
When a device is set to a particular Power State, it may be
busy. The device will set the desired Power State and then
update the actual Power State when it changes. There are then
two Power State control variables: actual and requested.
There are many existing standards for and implementations of
Power States. An Energy Object can support a mixed set of
Power States defined in different standards. A basic example
is given by the three Power States defined in IEEE1621
[IEEE1621]: on, off, and sleep. The DMTF [DMTF], ACPI [ACPI],
and PWG define larger numbers of Power States.
The semantics of a power state is specified by
a) the functionality provided by an Energy Object in this
state,
b) a limitation of the power that an Energy Object uses in
this state,
c) a combination of a) and b)
The semantics of a Power State should be clearly defined.
Limitation (curtailment) of the power used by an Energy Object
in a state can be specified by
- an absolute power value
- a percentage value of power relative to the energy
object's nameplate power
- an indication of used power relative to another power
state - for example: by stating used power in state A is less
than in state B.
For supporting Power State management it is useful to provide
statistics on Power States including the time an Energy Object
spent in a certain Power State and/or the number of times an
Energy Object entered a power state.
Power States should be registered at IANA with a name and a
number.
When requesting an Energy object to enter a Power State an
indication of its name or its number can be used. Optionally
an absolute or percentage of Nameplate Power can be provided
to allow the Energy Object to transition to a nearest or
equivalent Power State.
<Claise, et. Al> Expires August, 2013 [Page 36]
Internet-Draft <EMAN Framework> February 2013
EMAN Power State Set
An EMAN Power State Set represents an attempt for a standard
approach to model the different levels of power of a device.
The EMAN Power States are an expansion of the basic Power
States as defined in [IEEE1621] that also incorporates the
Power States defined in [ACPI] and [DMTF]. Therefore, in
addition to the non-operational states as defined in [ACPI]
and [DMTF] standards, several intermediate operational states
have been defined.
There are twelve Power States, that expand on [IEEE1621]. The
expanded list of Power States are derived from [CISCO-EW] and
are divided into six operational states, and six non-
operational states. The lowest non-operational state is 1 and
the highest is 6. Each non-operational state corresponds to
an [ACPI] Global and System states between G3 (hard-off) and
G1 (sleeping). Each operational state represents a
performance state, and may be mapped to [ACPI] states P0
(maximum performance power) through P5 (minimum performance
and minimum power).
In each of the non-operational states (from mechoff(1) to
ready(6)), the Power State preceding it is expected to have a
lower Power value and a longer delay in returning to an
operational state:
mechoff(1) : An off state where no Energy Object
features are available. The Energy Object is unavailable. No
energy is being consumed and the power connector can be
removed. This corresponds to ACPI state G3.
softoff(2) : Similar to mechoff(1), but some
components remain powered or receive trace power so that the
Energy Object can be awakened from its off state. In
softoff(2), no context is saved and the device typically
requires a complete boot when awakened. This corresponds to
ACPI state G2.
hibernate(3): No Energy Object features are
available. The Energy Object may be awakened without
requiring a complete boot, but the time for availability is
longer than sleep(4). An example for state hibernate(3) is a
save to-disk state where DRAM context is not maintained.
Typically, energy consumption is zero or close to zero. This
corresponds to state G1, S4 in ACPI.
<Claise, et. Al> Expires August, 2013 [Page 37]
Internet-Draft <EMAN Framework> February 2013
sleep(4) : No Energy Object features are
available, except for out-of-band management, such as wake-up
mechanisms. The time for availability is longer than
standby(5). An example for state sleep(4) is a save-to-RAM
state, where DRAM context is maintained. Typically, energy
consumption is close to zero. This corresponds to state G1,
S3 in ACPI.
standby(5) : No Energy Object features are available,
except for out-of-band management, such as wake-up mechanisms.
This mode is analogous to cold-standy. The time for
availability is longer than ready(6). For example, the
processor context is not maintained. Typically, energy
consumption is close to zero. This corresponds to state G1,
S2 in ACPI.
ready(6) : No Energy Object features are
available, except for out-of-band management, such as wake-up
mechanisms. This mode is analogous to hot-standby. The Energy
Object can be quickly transitioned into an operational state.
For example, processors are not executing, but processor
context is maintained. This corresponds to state G1, S1 in
ACPI. lowMinus(7) : Indicates some Energy Object
features may not be available and the Energy Object has
selected measures/options to provide less than low(8) usage.
This corresponds to ACPI State G0. This includes operational
states lowMinus(7) to full(12).
low(8) : Indicates some features may not be
available and the Energy Object has taken measures or selected
options to provideless than mediumMinus(9) usage.
mediumMinus(9): Indicates all Energy Object features
are available but the Energy Object has taken measures or
selected options to provide less than medium(10) usage.
medium(10) : Indicates all Energy Object features
are available but the Energy Object has taken measures or
selected options to provide less than highMinus(11) usage.
highMinus(11): Indicates all Energy Object features
are available and power usage is less than high(12).
high(12) : Indicates all Energy Object features
are available and the Energy Object is consuming the highest
power.
<Claise, et. Al> Expires August, 2013 [Page 38]
Internet-Draft <EMAN Framework> February 2013
A comparison of Power States can be seen in the following
table:
IEEE1621 DMTF ACPI EMAN
Non-operational states
off Off-Hard G3, S5 MechOff(1)
off Off-Soft G2, S5 SoftOff(2)
sleep Hibernate G1, S4 Hibernate(3)
sleep Sleep-Deep G1, S3 Sleep(4)
sleep Sleep-Light G1, S2 Standby(5)
sleep Sleep-Light G1, S1 Ready(6)
Operational states:
on on G0, S0, P5 LowMinus(7)
on on G0, S0, P4 Low(8)
on on G0, S0, P3 MediumMinus(9)
on on G0, S0, P2 Medium(10)
on on G0, S0, P1 HighMinus(11)
on on G0, S0, P0 High(12)
Figure 5: Comparison of Power States
4.7. Energy Management Reference Model
The scope of this framework is to enable network and network-
attached devices to be administered for Energy Management.
The framework recognizes that in complex deployments Energy
Objects may communicate over varying protocols. For example
the communications network may use IP Protocols (SNMP) but
attached Energy Object Parent may communicate to Energy Object
Children over serial communication protocols like BACNET,
MODBUS etc. The likelihood of getting these different
topologies to convert to a single protocol is not very high
considering the rate of upgrades of facilities and energy
related devices. Therefore the framework must address the
simple case of a uniform IP network and a more complex mixed
topology/deployment.
In this section we will describe the topologies that can exist
when describing a device, components and the relationships
among them.
We will then generalize those topologies by using an
information model based upon relationships. The most abstract
and general relationship between devices is a Parent and Child
<Claise, et. Al> Expires August, 2013 [Page 39]
Internet-Draft <EMAN Framework> February 2013
relationship. Specific types of relationships are defined and
used in concert to describe the topologies.
4.8 Using Device Relationships to Create Topologies
The reference models here define physical and logical
topologies of devices in a communication network.
The physical topology defined by the model defines
relationships between devices that reflect provisioning,
transfer of energy, and aid in management.
Logical topologies concern monitoring and controlling devices
and covers metering of energy and power, reporting information
relevant for energy management, and energy-related control of
devices.
Power Source Topology
As described in Section 4, the power source(s) of a device is
important for energy management. The Energy Management
reference model addresses this by a "Power Source"
Relationship. This is a relationship among devices providing
energy and devices receiving energy.
A simple example is a PoE PSE, for example, an Ethernet
switch, providing power to a PoE PD, for example, a desktop
phone. Here the switch provides energy and the phone receives
energy. This relationship can be seen in the figure below.
+----------+ power source +---------+
| switch | <-------------- | phone |
+----------+ +---------+
Figure 6: Simple Power Source
A single power provider can act as power source of multiple
power receivers. An example is a power distribution unit
(PDU) providing AC power for multiple switches.
+-------+ power source +----------+
| PDU | <----------+--- | switch 1 |
+-------+ | +----------+
|
| +----------+
+--- | switch 2 |
| +----------+
|
<Claise, et. Al> Expires August, 2013 [Page 40]
Internet-Draft <EMAN Framework> February 2013
| +----------+
+--- | switch 3 |
+----------+
Figure 7: Multiple Power Source
This level of modeling is sufficient if there is no need to
distinguish in monitoring and control between the individual
receivers at the switch.
However, if there is a need to monitor or control power supply
for individual receivers at the power provider, then a more
detailed level of modeling is needed.
Devices receive or provide energy at power interfaces
connecting them to a transmission medium. The Power Source
relationship can be used also between power interfaces at the
power provider side as well as at the power receiver side.
The example below shows a power providing device with a power
interface (PI) per connected receiving device.
+-------+------+ power source +----------+
| | PI 1 | <-------------- | switch 1 |
| +------+ +----------+
| |
| +------+ power source +----------+
| PDU | PI 2 | <-------------- | switch 2 |
| +------+ +----------+
| |
| +------+ power source +----------+
| | PI 3 | <-------------- | switch 3 |
+-------+------+ +----------+
Figure 8: Power Source with Power interfaces
Power interfaces may also be modeled at the receiving device,
for examples for consistency.
+-------+------+ power source +----+----------+
| | PI 1 | <-------------- | PI | switch 1 |
| +------+ +----+----------+
| |
| +------+ power source +----+----------+
| PDU | PI 2 | <-------------- | PI | switch 2 |
| +------+ +----+----------+
| |
| +------+ power source +----+----------+
<Claise, et. Al> Expires August, 2013 [Page 41]
Internet-Draft <EMAN Framework> February 2013
| | PI 3 | <-------------- | PI | switch 3 |
+-------+------+ +----+----------+
Figure 9: Power Interfaces at Receiving Device
Power Source relationships are between devices and their
interfaces. They are not transitive. In the examples below
there is a PDU powering a switch powering a phone.
+-------+ power +--------+ power +---------+
| PDU | <-------- | switch | <-------- | phone |
+-------+ source +--------+ source +---------+
Figure 10: Power Source Non-Transitive
Power Source Relationships are between the PDU and the switch
and between the switch and the phone. Transitively , there
exists a Power Source Relationship between the PDU and the
phone. .
+-------+ power +--------+ power +---------+
| PDU | <-------- | switch | <-------- | phone |
+-------+ source +--------+ source +---------+
^ |
| power source |
+------------------------------------------+
Figure 11: Power Source Transitive
Metering Topology
Case 1: Metering between two devices
The metering topology between two devices is closely related
to the power source topology. It is based on the assumption
that in many cases the power provided and the power received
is the same for both peers of a power source relationship.
Then power measured at one end can be taken as the actual
power value at the other end. Obviously, the same applies to
energy at both ends.
We define in this case a Metering Relationship between two
devices or power interfaces of devices that have a power
source relationship. Power and energy values measured at one
<Claise, et. Al> Expires August, 2013 [Page 42]
Internet-Draft <EMAN Framework> February 2013
peer of the power source relationship are reported for the
other peer as well.
The Metering Relationship is independent of the direction of
the Power Source Relationship. The more common case is that
values measured at the power provider are reported for the
power receiver, but also the reverse case is possible with
values measured at the power receiver being reported for the
power provider.
Power Power
+-----+----------+ Source +--------+ Source +-------+
| PDU |PI + meter| <-------- | switch | <------- | phone |
+-----+----------+ Metering +--------+ +-------+
^ |
| |
+-------------------------------------------+
metering
Figure 12: Direct and One Hop Metering
Case 2: Metering at a point in power distribution
A Sub-meter in a power distribution system can logically
measure the power or energy for all devices downstream from
the meter in the power distribution system. As such, a Power
metering relationship can be seen as a relationship between a
meter and all of the devices downstream from the meter.
We define in this case a Power Metering relationship between a
metering device and devices downstream from the meter.
In cases where the Power Source topology cannot be discovered
or derived from the information available in the Energy
Management Domain, the Metering Topology can be used to relate
the upstream meter to the downstream devices in the absence of
specific power source relationships.
A Metering Relationship can occur between devices that are not
directly connected as shown by the figure 13.
+---------------+
| Device 1 |
+---------------+
| PI |
+---------------+
|
+---------------+
<Claise, et. Al> Expires August, 2013 [Page 43]
Internet-Draft <EMAN Framework> February 2013
| Meter |
+---------------+
.
.
.
+----------+ +----------+ +-----------+
| Device A | | Device B | | Device C |
+----------+ +----------+ +-----------+
Figure 14: Complex Metering Topology
An analogy to communication networks would be modeling
connections between servers (meters) and clients (devices)
when the complete Layer 2 topology between the servers and
clients is not known.
Proxy Topology
Some devices may provide energy management capabilities on
behalf of other devices. For example, a controller may
logically model power interfaces but the physical topology may
require that the controller communicate to another device
using a building management protocol. These proxied devices
that are represented as power interfaces may be directly
connected or may be controlled over a communication network
with no direct connection.
The proxied device may or may not be IP connected. When it is
IP connected the communication may be via SNMP or any other
protocol.
While the EnMS may look at the logical representation of the
controller as a device with power interfaces, it may require
to report the physical topology and relationship to the
subtended devices. To model this we define a proxy
relationship to provide this visibility.
+-------+------+
| | PI 1 |
| +------+
| |
| +------+
| PDU | PI 2 |
| +------+
| |
| +------+
| | PI 3 |
+-------+------+
<Claise, et. Al> Expires August, 2013 [Page 44]
Internet-Draft <EMAN Framework> February 2013
+-------+ proxy +----+----------+
| |<--------- | PI 1 Physical |
| + +----+----------+
| |
| + proxy +----+----------+
| PDU |<--------- | PI 2 Physical |
| + +----+----------+
| |
| + proxy +----+----------+
| |<--------- | PI 3 Physical |
+-------+ +----+----------+
Figure 15: Proxy Relationship Virtual and Physical
Aggregation Topology
Some devices can act as aggregation points for other devices.
For example, a PDU controller device may contain the summation
of power and energy readings for many PDU devices. The PDU
controller will have aggregate values for power and energy for
a group of PDU devices.
This aggregation is independent of the physical power or
communication topology.
An Aggregation Relationship is an Energy Object Relationship
where one Energy Object (called the Aggregate Energy Object)
aggregates the Energy Management information of one or more
other Energy Objects. These Energy Objects are referred to as
having an Aggregation Relationship.
The functions that the aggregation point may perform include
the calculation of values such as average, count, maximum,
median, minimum, or the listing (collection) of the
aggregation values, etc.
Based on the experience gained on aggregations at the IETF
[draft-ietf-ipfix-a9n-08], the aggregation function in the
EMAN framework is limited to the summation.
While any power or energy values monitored from a device/power
interface can be seen as a summation for all devices
downstream from the monitoring device, the aggregation
relationship is used SHOULD BE instantiated to represent a
<Claise, et. Al> Expires August, 2013 [Page 45]
Internet-Draft <EMAN Framework> February 2013
summation when it is not obvious from the powering topology or
a device to component containment.
The Aggregation Relationship is then specified between the
Energy Object device containing aggregate values and each of
the other Energy Object devices for which the aggregation is
reported. If it does not exist, a new Aggregate Energy Object
specific for the Aggregation Relationship MUST be created.
EDITORs NOTE: add an outlet gang example and expand below.
A method to report on collections and summations of data is
to create special pseudo-devices. These could be tagged
in the MIB as not being a real device, but this may not be
needed. ThisA pseudo-device would have no power PIs Power
Interfaces, as to make clear that it does not interact with
the real power world. It contains components which are
actually entities from real devices and can be any
combination of devices, PIs, and real components. Most
commonly, a pseudo-device would contain a consistent set of
entities -
- a set of devices, a set of PIs, or a set of
components. The power/energy values for the entire pseudo-
device would be the sum of the components, as on a normal
device. This provides an easy way to access the sum, as
well as full documentation of what the components of that
sum are. This method is completely flexible and adds no
complexity to the EMAN framework or MIBs. Implementation of
this mechanism would be completely optional for EMAN
devices; likely most would not.
When aggregation occurs across a set of entities, values to be
aggregated may be missing for some entities. The EMAN
framework does not specify how these should be treated, as
different implementations may have good reason to take
different approaches. One common treatment is to define the
aggregation as missing if any of the constituent elements are
missing (useful to be most precise). Another is to treat the
missing value as zero (useful to have continuous data
streams).
The specifications of this aggregation function are out of
scope of the EMAN framework, but must be clearly specified by
the equipment vendor.
<Claise, et. Al> Expires August, 2013 [Page 46]
Internet-Draft <EMAN Framework> February 2013
EDITOR'S NOTE: 4 solutions discussed on December 12th
- pseudo device. Aggregate Energy Object
- A semantic field (ex: summation): extra index in every
measurement MIB table.
- Multiply the variables => doesn't work
- Remove aggregation
PREFERRED: take the proposal from Bruce (below) and let's
call pseud-device differently. Example Aggregate Energy
Object
4.9 Generalized Relationship Model
As displayed in Figure 15, the most basic energy management
reference model is composed of an EnMS that obtains Energy
Management information from Energy Objects. The Energy Object
(EO) returns information for Energy Management directly to the
EnMS.
The protocol of choice for Energy Management is SNMP, as three
MIBs are specified for Energy Management: the energy object
context MIB [EMAN-OBJECT-MIB], the energy monitoring MIB
[EMAN-MON-MIB], and the battery MIB [EMAN-BATTERY-MIB].
However, the EMAN requirement document [EMAN-REQ] also
requires support for a push model distribution of time series
values. The following diagrams mention IPFIX [RFC5101] as one
possible solution for implementing a push mode transfer,
however this is for illustration purposes only. The EMAN
standard does not require the use of IPFIX and acknowledges
that other alternative solutions may also be acceptable.
+---------------+
| EnMS | - -
+-----+---+-----+ ^ ^
| | | |
| | |S |I
+---------+ +----------+ |N |P
| | |M |F
| | |P |I
+-----------------+ +--------+--------+ | |X
| EO 1 | ... | EO N | v |
+-----------------+ +-----------------+ - -
<Claise, et. Al> Expires August, 2013 [Page 47]
Internet-Draft <EMAN Framework> February 2013
Figure 15: Simple Energy Management
As displayed in the Figure 16, a more complex energy reference
model includes Energy Managed Object Parents and Children.
The Energy Managed Object Parent returns information for
themselves as well as information according to the Energy
Managed Object Relationships.
+---------------+
| EnMS | - -
+-----+--+------+ ^ ^
| | | |
| | |S |I
+------------+ +--------+ |N |P
| | |M |F
| | |P |I
+------------------+ +------+-----------+ | |X
| EO | | EO | v |
| Parent 1 | ... | Parent N | - -
+------------------+ +------------------+
||| .
One or ||| .
Multiple ||| (*) .
Energy ||| .
Object ||| .
Relationship(s): |||
- Aggregation ||| +-----------------------+
- Metering |||------| EO Child 1 |
- Power Source || +-----------------------+
- Proxy ||
|| +-----------------------+
||-------| EO Child 2 |
| +-----------------------+
|
|
|-------- ...
|
|
| +-----------------------+
|--------| EO Child M |
+-----------------------+
<Claise, et. Al> Expires August, 2013 [Page 48]
Internet-Draft <EMAN Framework> February 2013
Figure 16: Complex Energy Management Model
While both the simple and complex Energy Management models
contain an EnMS, this framework doesn't impose any
requirements regarding a topology with a centralized EnMS(s)
or one with distributed Energy Management via the Energy
Objects within the deployment.
Given the pattern in Figure 16, the complex relationships
between Energy Objects can be modeled (refer also to section
5.3):
- A PoE device modeled as an Energy Object Parent with
the Power Source, Metering, and Proxy Relationships for
one or more Energy Object Children
- A PDU modeled as an Energy Object Parent with the Power
Source and Metering Relationships for the plugged in
Electrical Equipment (the Energy Object Children)
- Building management gateway, used as proxy for non IP
protocols, is modeled as an Energy Object Parent with
the Proxy Relationship, and potentially the Aggregation
Relationship to the managed Electrical Equipment
- Etc.
(*) If there is any communication between the Energy Object
Parent and Energy Object Children, it can be via EMAN and SNMP
(or IPFIX) but may be any other protocol IP or otherwise.
In the [EMAN-OBJECT-MIB], each Energy Object is managed with
an unique value of the entPhysicalIndex index from the ENTITY-
MIB [RFC4133]
The ENTITY-MIB [RFC4133] specifies the notion of physical
containment tree, as:
"Each physical component may be modeled as 'contained'
within
another physical component. A "containment-tree" is the
conceptual sequence of entPhysicalIndex values that uniquely
specifies the exact physical location of a physical
component within the managed system. It is generated by
'following and recording' each 'entPhysicalContainedIn'
instance 'up the tree towards the root', until a value of
zero indicating no further containment is found."
<Claise, et. Al> Expires August, 2013 [Page 49]
Internet-Draft <EMAN Framework> February 2013
A Energy Object Component is a special Energy Object that is a
physical component as specified by the ENTITY-MIB physical
containment tree.
5. Energy Management Information Model
The following basic UML represents an information model
expression of the concepts in this framework. This
information model, provided as a reference for implementers,
is represented as a MIB in the different related IETF Energy
Monitoring documents. However, other programming structure
with different data models could be used as well.
Notation is a shorthand UML with lowercase types considered
platform or atomic types (i.e. int, string, collection).
Uppercase types denote classes described further. Collections
and cardinality are expressed via qualifier notation.
Attributes labeled static are considered class variables and
global to the class. Arrows indicate inheritance. Algorithms
for class variable initialization, constructors or destructors
are not shown. Attrbutes and structures are considered
readable and writeable prefixed by a dash (-) which indicates
readonly.
<Claise, et. Al> Expires August, 2013 [Page 50]
Internet-Draft <EMAN Framework> February 2013
EO RELATIONSHIPS AND CONTEXT
+---------------------------------+
| Energy Object Information |
|---------------------------------|
| -index : int |
| name : string |
| -energy object Identifier : UUID|
| domain name : string |
| alternate Key : string |
+---------------------------------+
^
|
|
+---------------------------+
| EO Context Information |
|---------------------------|
| role : string |
| keywords[0..n] : string |
| importance : int |
| category : enum |
+---------------------------+
+---------------------------------+
| EO Relationship |
| ------------------------------- |
| -index : int |
| relation ID : UUID |
| relationship type: enum |
+---------------------------------+
+---------------------------------+
| EO Proxy Relationship |
| ------------------------------- |
| -index : int |
| proxy ID : UUID |
| proxy abilities : enum |
+---------------------------------+
<Claise, et. Al> Expires August, 2013 [Page 51]
Internet-Draft <EMAN Framework> February 2013
EO AND MEASUREMENTS
+-----------------------------------------------+
| Energy Object |
|-----------------------------------------------|
| -nameplate : Measurement |
| current : enum { AC, DC } |
| origin : enum { self, remote } |
| battery[0..n]: Battery |
| measurements[0..n]: Measurement |
| status: |
| --------------------------------------------- |
| Measurement instantaneousUsage() |
| DemandMeasurement historicalUsage() |
+-----------------------------------------------+
+---------------------------------------+
| -Measurement |
+---------------------------------------+
| multiplier : enum {-24..24} |
| caliber : enum { actual, estimated, |
| trusted, assumed...} |
| accuracy : enum { 0..10000} |
| time : timestamp |
+---------------------------------------+
^ ^
| |
| +------------------+------------------+
| | -Power Measurement |
| |-------------------------------------|
| | value : long |
| | units : "watts" |
| | rate : enum {0,millisecond,seconds, |
| | minutes,hours,...} |
| | quality : PowerQuality |
| +-------------------------------------+
|
|
+------------------+----------------------------+
| -Energy Measurement |
|-----------------------------------------------|
| collection start time : time |
| units : enum |
| consumed : long |
| produced : long |
<Claise, et. Al> Expires August, 2013 [Page 52]
Internet-Draft <EMAN Framework> February 2013
| net : long |
| max consumed : long |
| max produced : long |
+-----------------------------------------------+
+-----------------------------------------------+
| -Time |
|-----------------------------------------------|
| startTime : timestamp |
| usage : Measurement |
| maxUsage : Measurement |
+-----------------------------------------------+
|
|
+----------------------------------------+
| -TimeInterval |
|--------------------------------------- |
|value : long |
|units : enum { seconds, miliseconds..} |
+----------------------------------------+
|
|
+----------------------------------------+
| -DemandMeasurement |
|----------------------------------------|
|intervalLength : TimeInterval |
|intervalNumbers: long |
|intervalMode : enum { period, sliding, |
|total } |
|intervalWindow : TimeInterval |
|sampleRate : TimeInterval |
|status : enum {active, inactive } |
|measurements : TimedMeasurement[] |
+----------------------------------------+
<Claise, et. Al> Expires August, 2013 [Page 53]
Internet-Draft <EMAN Framework> February 2013
ATTRIBUTES
+----------------------------------------+
| -PowerAttributes |
|----------------------------------------|
| |
+----------------------------------------+
^
|
|
+------------------+--------------------+
| -ACQuality |
|---------------------------------------|
| acConfiguration : enum {SNGL, DEL,WYE}|
| avgVoltage : long |
| avgCurrent : long |
| frequency : long |
| unitMultiplier : int |
| accuracy : int |
| totalActivePower : long |
| totalReactivePower : long |
| totalApparentPower : long |
| totalPowerFactor : long |
+---------+-----------------------------+
| 1
|
|
|
| +------------------------------------+
| | -ACPhase |
| * |------------------------------------|
+--------+ phaseIndex : long |
| avgCurrent : long |
| activePower : long |
| reactivePower : long |
| apparentPower : long |
| powerFactor : long |
+------------------------------------+
^ ^
| |
| |
| |
| |
+-------------------------------+---+ |
| -DelPhase | |
|-----------------------------------| |
|phaseToNextPhaseVoltage : long | |
|thdVoltage : long | |
<Claise, et. Al> Expires August, 2013 [Page 54]
Internet-Draft <EMAN Framework> February 2013
|thdCurrent : long | |
+-----------------------------------+ |
|
+------------------+-----------+
| -WYEPhase |
|------------------------------|
|phaseToNeutralVoltage : long |
|thdCurrent : long |
|thdVoltage : long |
+------------------------------+
EO & STATES
+----------------------------------------------+
| Energy Object |
|----------------------------------------------|
| -currentLevel : int |
| configuredLevel : int |
| -configuredTime : timestamp |
| reason: string |
| powerStateSeries[0..n] : array of State |
| adminState : enum |
| operState : enum |
+----------------------------------------------+
+-------------------------------+
| State |
|-------------------------------|
| name : string |
| cardinality : int |
| maxUsage : Measurement |
| totalTime : time |
| enterCount : int |
+-------------------------------+
Figure 17: Information Model UML Representation
<Claise, et. Al> Expires August, 2013 [Page 55]
Internet-Draft <EMAN Framework> February 2013
6. Example Topologies
In this section we will give examples of how to use the Energy
Management framework. In each example we will show how it can
be applied when Devices have the capability to model Power
Interfaces. We will also show in each example how the
framework can be applied when devices cannot support Power
Interfaces but only monitor information or control the Device
as a whole. For instance a PDU may only be able to measure
power and energy for the entire unit without the ability to
distinguish among the inlets or outlet.
Together these examples show how the framework can be adapted
for Devices with different capabilities (typically hardware)
for Energy Management.
Given for all Examples:
Device W: A computer with one power supply. Power interface 1
is an inlets for Device W.
Device X: A computer with two power supplies. Power interface
1 and power interface 2 are both inlets for Device X.
Device Y: A PDU with multiple Power Interfaces numbered 0..10,
Power interface 0 is an inlet and power interface 1..10 are
outlets.
Device Z: A PDU with multiple Power Interfaces numbered 0..10,
Power interface 0 is an inlet and power interface 1..10 are
outlets.
6.1 Example I: Simple Device with one Source
Topology:
Device W inlet 1 is plugged into Device Y outlet 8.
With Power Interfaces:
Device W has an Energy Object representing the computer
itself as well as one Power Interface defined as an inlet.
Device Y would have an Energy Object representing the PDU
itself (the Device) with a Power Interface 0 defined as an
inlet and Power Interfaces 1..10 defined as outlets.
<Claise, et. Al> Expires August, 2013 [Page 56]
Internet-Draft <EMAN Framework> February 2013
The interfaces of the devices would have a Power Source
Relationship such that:
Device W inlet 1 is powered by Device Y outlet 8
Without Power Interfaces:
In this case Device W has an Energy Object representing the
computer. Device Y would have an Energy Object representing
the PDU.
The devices would have a Power Source Relationship such
that:
Device W is powered by Device Y.
6.2 Example II: Multiple Inlets
Topology:
Device X inlet 1 is plugged into Device Y outlet 8.
Device X inlet 2 is plugged into Device Y outlet 9.
With Power Interfaces:
Device X has an Energy Object representing the computer
itself. It contains two Power Interface defined as inlets.
Device Y would have an Energy Object representing the PDU
itself (the Device) with a Power Interface 0 defined as an
inlet and Power Interface 1..10 defined as outlets.
The interfaces of the devices would have a Power Source
Relationship such that:
Device X inlet 1 is powered by Device Y outlet 8
Device X inlet 2 is powered by Device Y outlet 9
Without Power Interfaces:
In this case Device X has an Energy Object representing the
computer. Device Y would have an Energy Object representing
the PDU.
The devices would have a Power Source Relationship such
that:
Device X is powered by Device Y.
<Claise, et. Al> Expires August, 2013 [Page 57]
Internet-Draft <EMAN Framework> February 2013
6.3 Example III: Multiple Sources
Topology:
Device X inlet 1 is plugged into Device Y outlet 8.
Device X inlet 2 is plugged into Device Z outlet 9
With Power Interfaces:
Device X has an Energy Object representing the computer
itself. It contains two Power Interface defined as inlets.
Device Y would have an Energy Object representing the PDU
itself (the Device) with a Power Interface 0 defined as an
inlet and Power Interface 1..10 defined as outlets.
Device Z would have an Energy Object representing the PDU
itself (the Device) with a Power Interface 0 defined as an
inlet and Power Interface 1..10 defined as outlets.
The interfaces of the devices would have a Power Source
Relationship such that:
Device X inlet 1 is powered by Device Y outlet 8
Device X inlet 2 is powered by Device Z outlet 9
Without Power Interfaces:
In this case Device X has an Energy Object representing the
computer. Device Y and Z would both have respective Energy
Objects representing each entire PDU.
The devices would have a Power Source Relationship such
that:
Device X is powered by Device Y and powered by Device Z.
7. Relationship with Other Standards
This power management framework should, as much as possible,
reuse existing standards efforts, especially with respect to
information modeling and data modeling [RFC3444].
<Claise, et. Al> Expires August, 2013 [Page 58]
Internet-Draft <EMAN Framework> February 2013
The data model for power and energy related objects is based
on IEC 61850.
Specific examples include:
The scaling factor, which represents Energy Object usage
magnitude, conforms to the IEC 61850 definition of unit
multiplier for the SI (System International) units of measure.
The electrical characteristic is based on the ANSI and IEC
Standards, which require that we use an accuracy class for
power measurement. ANSI and IEC define the following accuracy
classes for power measurement:
IEC 62053-22 60044-1 class 0.1, 0.2, 0.5, 1 3.
ANSI C12.20 class 0.2, 0.5
The electrical characteristics and quality adheres closely to
the IEC 61850 7-2 standard for describing AC measurements.
The power state definitions are based on the DMTF Power State
Profile and ACPI models, with operational state extensions.
8. Security Considerations
Regarding the data attributes specified here, some or all may
be considered sensitive or vulnerable in some network
environments. Reading or writing these attributes without
proper protection such as encryption or access authorization
may have negative effects on the network capabilities.
Security Considerations for SNMP
<Claise, et. Al> Expires August, 2013 [Page 59]
Internet-Draft <EMAN Framework> February 2013
Readable objects in a MIB modules (i.e., objects with a MAX-
ACCESS other than not-accessible) may be considered sensitive
or vulnerable in some network environments. It is thus
important to control GET and/or NOTIFY access to these objects
and possibly to encrypt the values of these objects when
sending them over the network via SNMP.
The support for SET operations in a non-secure environment
without proper protection can have a negative effect on
network operations. For example:
Unauthorized changes to the Energy Management Domain or
business context of an Energy Object may result in
misreporting or interruption of power.
Unauthorized changes to a power state may disrupt the power
settings of the different Energy Objects, and therefore the
state of functionality of the respective Energy Objects.
Unauthorized changes to the demand history may disrupt proper
accounting of energy usage.
With respect to data transport SNMP versions prior to SNMPv3
did not include adequate security. Even if the network itself
is secure (for example, by using IPsec), there is still no
secure control over who on the secure network is allowed to
access and GET/SET (read/change/create/delete) the objects in
these MIB modules.
It is recommended that implementers consider the security
features as provided by the SNMPv3 framework (see [RFC3410],
section 8), including full support for the SNMPv3
cryptographic mechanisms (for authentication and privacy).
Further, deployment of SNMP versions prior to SNMPv3 is not
recommended. Instead, it is recommended to deploy SNMPv3 and
<Claise, et. Al> Expires August, 2013 [Page 60]
Internet-Draft <EMAN Framework> February 2013
to enable cryptographic security. It is then a
customer/operator responsibility to ensure that the SNMP
entity giving access to an instance of these MIB modules is
properly configured to give access to the objects only to
those principals (users) that have legitimate rights to GET or
SET (change/create/delete) them.
9. IANA Considerations
Initial values for the Power State Sets, together with the
considerations for assigning them, are defined in [EMAN-MON-
MIB].
10. Acknowledgments
The authors would like to Michael Brown for improving the text
dramatically, and Rolf Winter for his feedback. The award for
the best feedback and reviews goes to Bill Mielke.
11. References
Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2819] S. Waldbusser, "Remote Network Monitoring
Management Information Base", STD 59, RFC 2819, May
2000
[RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for
Internet Standard Management Framework ", RFC 3410,
December 2002.
[RFC4133] Bierman, A. and K. McCloghrie, "Entity MIB
(Version3)", RFC 4133, August 2005.
<Claise, et. Al> Expires August, 2013 [Page 61]
Internet-Draft <EMAN Framework> February 2013
[RFC4122] Leach, P., Mealling, M., and R. Salz," A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
July 2005
Informative References
[RFC2578] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Structure of Management Information Version 2
(SMIv2", RFC 2578, April 1999
[RFC3444] Pras, A., Schoenwaelder, J. "On the Differences
between Information Models and Data Models", RFC
3444, January 2003.
[RFC5101] B. Claise, Ed., Specification of the IP Flow
Information Export (IPFIX) Protocol for the Exchange
of IP Traffic Flow Information, RFC 5101, January
2008.
[RFC6020] M. Bjorklund, Ed., " YANG - A Data Modeling Language
for the Network Configuration Protocol (NETCONF)",
RFC 6020, October 2010.
[ACPI] "Advanced Configuration and Power Interface
Specification", http://www.acpi.info/spec30b.htm
[IEEE1621] "Standard for User Interface Elements in Power
Control of Electronic Devices Employed in
Office/Consumer Environments", IEEE 1621, December
2004.
[LLDP] IEEE Std 802.1AB, "Station and Media Control
Connectivity Discovery", 2005.
[LLDP-MED-MIB] ANSI/TIA-1057, "The LLDP Management
Information Base extension module for TIA-TR41.4
media endpoint discovery information", July 2005.
[EMAN-REQ] Quittek, J., Winter, R., Dietz, T., Claise, B., and
M. Chandramouli, "Requirements for Energy
Management", draft-ietf-eman-requirements-09, (work
in progress), November 2011.
[EMAN-OBJECT-MIB] Parello, J., and B. Claise, "Energy Object
Contet MIB", draft-ietf-eman-energy-aware-mib-07,
(work in progress), October 2012.
<Claise, et. Al> Expires August, 2013 [Page 62]
Internet-Draft <EMAN Framework> February 2013
[EMAN-MON-MIB] Chandramouli, M.,Schoening, B., Quittek, J.,
Dietz, T., and B. Claise, "Power and Energy
Monitoring MIB", draft-ietf-eman-energy-monitoring-
mib-03, (work in progress), March 2012.
[EMAN-BATTERY-MIB] Quittek, J., Winter, R., and T. Dietz, "
Definition of Managed Objects for Battery
Monitoring", draft-ietf-eman-battery-mib-06, (work in
progress), March 2012.
[EMAN-AS] Schoening, B., Chandramouli, M., and B. Nordman,
"Energy Management (EMAN) Applicability Statement",
draft-ietf-eman-applicability-statement-02, (work in
progress), October 2011
[EMAN-TERMINOLOGY] J. Parello, "Energy Management
Terminology", draft-parello-eman-definitions-06,
(work in progress), March 2012
[ITU-T-M-3400] TMN recommandation on Management Functions
(M.3400), 1997
[NMF] "Network Management Fundamentals", Alexander Clemm,
ISBN: 1-58720-137-2, 2007
[TMN] "TMN Management Functions : Performance Management",
ITU-T M.3400
[1037C] US Department of Commerce, Federal Standard 1037C,
http://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm
[IEEE100] "The Authoritative Dictionary of IEEE Standards
Terms"
http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?pu
number=4116785
[DASH] "Desktop and mobile Architecture for System Hardware",
http://www.dmtf.org/standards/mgmt/dash/
[ISO50001] "ISO 50001:2011 Energy management systems -
Requirements with guidance for use",
http://www.iso.org/
[IEC60050] International Electrotechnical Vocabulary
http://www.electropedia.org/iev/iev.nsf/welcome?openf
orm
[SQL] ISO/IEC 9075(1-4,9-11,13,14):2008
<Claise, et. Al> Expires August, 2013 [Page 63]
Internet-Draft <EMAN Framework> February 2013
[IEEE-802.3at] IEEE 802.3 Working Group, "IEEE Std 802.3at-
2009 - IEEE Standard for Information technology -
Telecommunications and information exchange between
systems - Local and metropolitan area networks -
Specific requirements - Part 3: Carrier Sense
Multiple Access with Collision Detection (CSMA/CD)
Access Method and Physical Layer Specifications -
Amendment: Data Terminal Equipment (DTE) - Power via
Media Dependent Interface (MDI) Enhancements",
October 2009.
[DMTF] "Power State Management Profile DMTF DSP1027 Version
2.0" December 2009
http://www.dmtf.org/sites/default/files/standards/doc
uments/DSP1027_2.0.0.pdf
[IPENERGY] R. Aldrich, J. Parello "IP-Enabled Energy
Management", 2010, Wiley Publishing
[X.700] CCITT Recommendation X.700 (1992), Management
framework for Open Systems Interconnection (OSI) for
CCITT applications.
[ASHRAE-201] "ASHRAE Standard Project Committee 201
(SPC 201)Facility Smart Grid Information
Model", http://spc201.ashraepcs.org
[CHEN] "The Entity-Relationship Model: Toward a Unified View
of Data", Peter Pin-shan Chen, ACM Transactions on
Database Systems, 1976
[CISCO-EW] "Cisco EnergyWise Design Guide", John Parello,
Roland Saville, Steve Kramling, Cisco Validated
Designs, September 2010,
http://www.cisco.com/en/US/docs/solutions/Enterprise/
Borderless_Networks/Energy_Management/energywisedg.ht
ml
Authors' Addresses
Benoit Claise
Cisco Systems, Inc.
De Kleetlaan 6a b1
Diegem 1813
<Claise, et. Al> Expires August, 2013 [Page 64]
Internet-Draft <EMAN Framework> February 2013
BE
Phone: +32 2 704 5622
Email: bclaise@cisco.com
John Parello
Cisco Systems, Inc.
3550 Cisco Way
San Jose, California 95134
US
Phone: +1 408 525 2339
Email: jparello@cisco.com
Brad Schoening
44 Rivers Edge Drive
Little Silver, NJ 07739
US
Phone:
Email: brad.schoening@verizon.net
Juergen Quittek
NEC Europe Ltd.
Network Laboratories
Kurfuersten-Anlage 36
69115 Heidelberg
Germany
Phone: +49 6221 90511 15
EMail: quittek@netlab.nec.de
Bruce Nordman
Lawrence Berkeley National Laboratory
1 Cyclotron Road
Berkeley 94720
US
Phone: +1 510 486 7089
Email: bnordman@lbl.gov
<Claise, et. Al> Expires August, 2013 [Page 65]