One document matched: draft-quittek-eman-reference-model-02.txt
Differences from draft-quittek-eman-reference-model-01.txt
Network Working Group J. Quittek
Internet-Draft NEC Europe Ltd.
Intended status: Informational B. Nordman
Expires: January 12, 2012 Lawrence Berkeley National
Laboratory
July 11, 2011
Reference Model for Energy Management
draft-quittek-eman-reference-model-02
Abstract
This memo proposes a reference model for energy consumption
monitoring and control. It claims that the only basic extension of
conventional network management models is the concept of power
interfaces of managed entities. Power interfaces can be treated
similarly to network interfaces. They have different modes (outlet,
inlet, probe) and their connections to transmission media (lines)
define a power supply topology among the involved managed entities.
This memo elaborates an information model for power interfaces that
meets the requirements for energy management.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 12, 2012.
Copyright Notice
Copyright (c) 2011 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
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publication of this document. Please review these documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Energy Management . . . . . . . . . . . . . . . . . . . . 5
2.2. Power . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Energy . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Energy Management Reference Model . . . . . . . . . . . . . . 5
3.1. Power Interface (PI) . . . . . . . . . . . . . . . . . . . 5
3.1.1. Powered Entity (PE) . . . . . . . . . . . . . . . . . 6
3.1.2. Power Source (PS) . . . . . . . . . . . . . . . . . . 6
3.1.3. Power Meter (PM) . . . . . . . . . . . . . . . . . . . 6
3.2. Power supply topology . . . . . . . . . . . . . . . . . . 6
3.2.1. Lack of instrumentation . . . . . . . . . . . . . . . 8
3.2.2. Remote power measurement . . . . . . . . . . . . . . . 8
3.2.3. Aggregated power measurement . . . . . . . . . . . . . 8
3.2.4. Remote power supply control . . . . . . . . . . . . . 9
3.2.5. Aggregated power supply control . . . . . . . . . . . 9
3.3. Basic functions of energy management . . . . . . . . . . . 9
3.4. Energy management information model . . . . . . . . . . . 10
4. Security Considerations . . . . . . . . . . . . . . . . . . . 12
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
7. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Change mode from inlet to outlet? . . . . . . . . . . . . 12
7.2. Collector and Aggregator . . . . . . . . . . . . . . . . . 12
8. Informative References . . . . . . . . . . . . . . . . . . . . 12
Appendix A. Energy Monitoring Reference Model Version -01 . . . . 14
A.1. Introduction to Energy Monitoring . . . . . . . . . . . . 14
A.1.1. Basic Energy Monitoring (local metering) . . . . . . . 14
A.1.2. External Metering . . . . . . . . . . . . . . . . . . 14
A.1.3. Functions and Entities . . . . . . . . . . . . . . . . 15
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A.1.4. Power Monitors . . . . . . . . . . . . . . . . . . . . 15
A.2. Energy Monitoring Entities . . . . . . . . . . . . . . . . 17
A.2.1. Powered Device . . . . . . . . . . . . . . . . . . . . 17
A.2.2. Power Source . . . . . . . . . . . . . . . . . . . . . 17
A.2.3. Power Meter . . . . . . . . . . . . . . . . . . . . . 17
A.2.4. Power Monitors . . . . . . . . . . . . . . . . . . . . 17
A.2.4.1. Power State Monitor . . . . . . . . . . . . . . . 18
A.2.4.2. Power Source Monitor . . . . . . . . . . . . . . . 18
A.2.4.3. Power Usage Monitor . . . . . . . . . . . . . . . 18
A.2.5. Energy Monitoring System . . . . . . . . . . . . . . . 18
A.3. Standardization Scope . . . . . . . . . . . . . . . . . . 18
A.4. Entity Relationships . . . . . . . . . . . . . . . . . . . 19
A.5. Energy Monitoring Scenarios . . . . . . . . . . . . . . . 19
A.5.1. Simple Device with Power Meter . . . . . . . . . . . . 19
A.5.2. External Power Meter . . . . . . . . . . . . . . . . . 20
A.5.3. External Power Meter for Multiple Powered Devices . . 21
A.5.4. Powered Device with Dual Power Supply . . . . . . . . 22
A.5.5. Two energy monitoring systems . . . . . . . . . . . . 23
A.5.6. Power over Ethernet Switch . . . . . . . . . . . . . . 24
A.5.7. Power Distribution Unit . . . . . . . . . . . . . . . 25
A.5.8. Aggregator . . . . . . . . . . . . . . . . . . . . . . 25
A.5.9. Energy Monitoring Gateway . . . . . . . . . . . . . . 26
A.5.10. Further Scenarios . . . . . . . . . . . . . . . . . . 27
Appendix B. Energy Management Reference Model version -01 . . . . 27
B.1. Energy Management Entities . . . . . . . . . . . . . . . . 28
B.1.1. Powered Device . . . . . . . . . . . . . . . . . . . . 28
B.1.2. Power Source . . . . . . . . . . . . . . . . . . . . . 29
B.1.3. Power Meter . . . . . . . . . . . . . . . . . . . . . 29
B.1.4. Power Controllers . . . . . . . . . . . . . . . . . . 29
B.1.4.1. Power State Controller . . . . . . . . . . . . . . 29
B.1.4.2. Power Source Controller . . . . . . . . . . . . . 29
B.1.4.3. Power Meter Controller . . . . . . . . . . . . . . 29
B.1.5. Energy Management System . . . . . . . . . . . . . . . 29
B.2. Reference Points . . . . . . . . . . . . . . . . . . . . . 30
B.3. Entity Relationships . . . . . . . . . . . . . . . . . . . 30
B.4. Energy Management Scenarios . . . . . . . . . . . . . . . 30
B.4.1. Simple Self-Managed Device . . . . . . . . . . . . . . 30
B.4.2. Simple Managed Device . . . . . . . . . . . . . . . . 32
B.4.3. Power over Ethernet Switch . . . . . . . . . . . . . . 34
B.4.4. Power Distribution Unit . . . . . . . . . . . . . . . 35
B.4.5. Energy Management Gateway . . . . . . . . . . . . . . 35
B.4.6. Further Scenarios . . . . . . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 36
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1. Introduction
Managing energy consumption of devices with network connections is
different from several well understood network management functions
because of the special nature of energy supply and consumption.
A simple example of energy management is a single device reporting
information about its own energy status. It may have local energy
control mechanisms, for example putting itself into a sleep mode when
appropriate and it may receive energy control commands from a
management system. This and similar cases are well understood and
can be handled with well established and standardized management
procedures. The only missing components today are standardized ways
for reporting energy consumption information, such as, for example,
specific MIB modules, and for controlling energy consumption, such
as, for example, a specific YANG model. The simple example is also
likely to be most common and cover most energy use for the
foreseeable future.
Energy management has some differences from other common network
management tasks. This is caused by the nature of energy supply and
consumption and by the commonly deployed technologies:
o Energy supply for powered devices is often controlled by other
devices that we call power sources. Examples of power sources are
Power Distribution Units (PDUs) for AC power supply and Power over
Ethernet (PoE) switches providing DC power over Ethernet cables.
Thus power supply control for a specific powered device is often
conducted through interaction the corresponding power source and
not with the particular device. Also monitoring of power supply
for a specific device may include interaction with the
corresponding power source.
o In many cases, energy consumption is not measured by the powered
device itself, but by a power meter located upstream in the power
distribution tree. An example is a power distribution unit (PDU)
that measures energy consumption of attached devices and may
report this to an energy management system. Unlike many other
management functions, the powered device is not involved in this
process.
o A power meter measuring at the outlet of a PDU or at a power
supply line may measure the accumulated power of several powered
devices supplied via the outlet or the power line. In such a case
no separate power values can be measured for the individual
powered devices, but only the sum of the power of all devices
powered via the outlet or power line is available.
This memo aims to clarify roles of entities involved in energy
monitoring and control and the relationships among them. This is
achieved by defining a model for energy management that particularly
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covers the special issues of energy management including, but not
limited to the three issues listed above.
Version -01 of this model presented in the previous version of this
draft was focusing on devices or entities involved in energy
management. This version -02 is completely different. It is based
on the concept of a power interface. The result is much simpler and
very close to the common concept of a network interface. For
comparison, version -01 of the model is appended to the end of this
memo as Appendices A and B.
There is already a reference model defined in section 4 of
[I-D.ietf-eman-framework]. The intention of this memo is to refine
this model based on recent discussions.
2. Terminology
This section defines terms used for the description of the energy
management reference model. Terms specific to the reference model
are defined in Section 3.1.
2.1. Energy Management
To be agreed on in the EMAN WG.
2.2. Power
To be agreed on in the EMAN WG.
2.3. Energy
To be agreed on in the EMAN WG.
3. Energy Management Reference Model
This section specifies a reference model for energy monitoring. The
basic extension that the model makes on top of existing network
management models is that it introduced the concept of power
interfaces in addition to network interfaces of managed entities.
3.1. Power Interface (PI)
The term 'power interface' is not new. It is already used by the
IEEE standard for Power over Ethernet (PoE) [IEEE-802.3at]. There
are some similarities between power interfaces and network
interfaces. A network interface can be used in different modes, such
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as sending or receiving on an attached line. A PI can have the
following modes:
o inlet: receiving power
o outlet: providing power
In addition, like a network interface, it can be monitoring the
shared (power) transmission media and meter power and other electric
quantities on it. PIs with metering capability is called a meter PI.
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, a
current clamp of an ammeter, etc.
Derived from the terminology defined by the IEEE standard for Power
over Ethernet (PoE) in [IEEE-802.3af] and [IEEE-802.3at] we define
the following terms:
3.1.1. Powered Entity (PE)
An entity with one or more PIs in mode "inlet" is called a Powered
Entity (PE). This extends the term Powered Device (PD) used in
[IEEE-802.3af] and [IEEE-802.3at] to cover not only entities that are
individual devices, but also entities that are just components of
devices.
3.1.2. Power Source (PS)
An entity with one or more PIs in mode "outlet" is called a Power
Source (PS). Note that this extends the term Power Source Equipment
(PSE) used in the IEEE PoE standards [IEEE-802.3af] and
[IEEE-802.3at] where at a single PI the PSE provides power to a
single PD only. Here a PS may supply arbitrary numbers of PEs at a
single PI. Note further that most PSs have also PIs in mode "inlet"
and thus are also a PE.
3.1.3. Power Meter (PM)
An entity with a meter PI is called a Power Meter (PM) for this PI.
3.2. Power supply topology
Similar to network interfaces, power interface can be connected to
each other. The most simple connection is a single outlet connected
to a single inlet as shown in Figure 1.
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+--------------------------+ +----------------+
| Power Source | | Powered Entity |
| +---------+ | | +---------+ |
| | PI | | | | PI | |
| | (outlet)########## (inlet) | |
| +---------+ | | +---------+ |
+--------------------------+ +----------------+
######## power supply line
Figure 1: Simple one-to-one power supply topology
Figure 2 shows a more complex example. Here a PS has two power
outlets, one of them with metering capability. Note that because is
has also a PI in mode "inlet" it is also a PE. At one outlet, the PE
supplies two PEs. The power supply line connected to this PI is also
monitored by a PM. Note that the PM can only measure the accumulated
power of the two supplied PEs. It cannot differentiate which part of
the measured values relates to an individual PE.
+----------------+
| Powered Entity |
| +------------+ |
+-------------+ | | PI (inlet, | |
| Power Meter | ##### meter) | |
| +---------+ | # | +------------+ |
| | PI | | # +----------------+
+--------------------------+ | | (meter) | | #
| PS/PE | | +----#----+ | # +----------------+
| +---------+ | +------#------+ # | Powered Entity |
| | PI #2 | | # # | +------------+ |
| | (outlet)########################### PI (inlet) | |
| +---------+ +---------+ | | +------------+ |
| | PI #1 | | +----------------+
##### (inlet) | |
| +---------+ +---------+ | +----------------+
| | PI #3 | | | Powered Entity |
| | (outlet,| | | +------------+ |
| | meter) | ########################### PI (inlet) |
| +---------+ | | +------------+ |
+--------------------------+ +----------------+
######## power supply line
Figure 2: More complex power supply topology
Figure 2 shows an example in which the metering function is not
within the PE being metered. We see that for energy management in
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this type of deployment it is important to monitor power interfaces
and as well to detect the energy supply topology by finding out which
PIs are connected with each other by power supply lines.
Also from the example scenario in Figure 2 we can identify the
following issues for energy management:
3.2.1. Lack of instrumentation
Many PEs and PSs are not sufficiently instrumented to monitor their
own power interface(s). If there is no other entity that has
capabilities to collect data on these interfaces, then this
information is not available for energy management.
3.2.2. Remote power measurement
In many cases PSs or PMs have the capability to provide power
measurements for other entities. Examples are a Power Distribution
Unit (PDU) and a Power over Ethernet (PoE) Power Sourcing Equipment
(PSE). These entities often have the capability to measure power per
power outlet. In such a case an association between the measurement
values and the (potentially remote) entities that consume the
measured power needs to be established. the association is given by
the power supply topology.
There are two examples for this in Figure 2. The first one is PI #3
of the PS/PE that provides power measurement for the PE connected to
this PI. The second one is the PM that provides power metering for
PI #2 of the PS/PE which is an aggregated power measurement for the
two PEs connected to this PI.
3.2.3. Aggregated power measurement
An entity providing power at outlets may supply more than one other
entity with a single outlet. In such a case power measurements
conducted at the outlet are aggregated measurement for all powered
entities that have their power inlets connected to this outlet.
Separate values for the individual supplied entities are not
available in this case. Furthermore, for the energy management
system it would be highly desirable to receive information on which
entities are actually receiving the power provided at the outlet.
An examples for this is the PM in Figure 2. It provides an
aggregated power measurement for the two PEs connected to this PI.
Only with additional power metering at the PI of one of the PEs power
values for the individual PEs can be determined.
Note that in some cases, some or all of the PEs attached to an
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aggregated outlet will have their own metering capabilities. A
typical AC mains circuit breaker is an example of an aggregated
outlet with many devices powered off of a single supply point.
3.2.4. Remote power supply control
There are three ways for an energy management system to change the
power state of a managed entity. First is for a management system to
provide policy or other useful information (like the electricity
price) to the PE for it to use in determining its power state. The
second is sending the entity a command to switch to another state.
The third is to utilize an upstream device (to the PE) that has
capabilities to switch on and off power at its outlet. Some entities
do not have capabilities for receiving commands or changing their
power states by themselves. Such devices may be controlled by
switching on and off the power supply for them and so have particular
need for the third method.
In Figure 2 the PS/PE can switch on and off power at its two PIs in
outlet mode and thereby switch on and off power supply for the
respective connected PEs.
3.2.5. Aggregated power supply control
The issue of supplying multiple PEs via a single power outlet of a
device is also relevant for power control. Here it must be
considered that by switching off power at such an outlet, multiple
entities might be switched on or off simultaneously.
The example for this in Figure 2 is PI #2 of the PS/PE. It cannot
switch power separately for an individual PE. Every power switching
action affects the two connected PEs in the same way.
3.3. Basic functions of energy management
Based on the concept of power interfaces and the implications of
potential power supply topologies discussed above, the basic
functions of energy management can be defined. For our energy
management reference model we consider five basic energy management
functions:
1. monitoring power states (on, off, sleep, etc.) of PEs
2. controlling power states of PEs
3. monitoring PIs (inlets, outlets, probes)
4. controlling PIs
5. detecting power supply topologies
Monitoring and controlling power states of PEs (functions 1. and 2.)
has many similarities with conventional network management functions.
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The reference model includes them for completeness, but not many
special arrangements are necessary for dealing with them. One
special issue might be finding ways to monitor and control entities
that are in a sleep state or an off state, as these may lack the
normal network interaction capabilities of entities that are fully
on. A second issue that may occur is proxying power state
information for other entities, for example when the entities do not
have IP interfaces themselves, but can communicate with the Internet
only via gateways. But for proxying of information, sufficient
conventional means are available.
More challenging are functions 3. to 5. For monitoring PIs it may be
difficult to determine where information on a PI is available. As
shown in Figure 2 a PI in inlet mode (without metering capability)
may receive power values from a PM, or from a supplying PI in outlet
mode. Vice versa, a PI in outlet mode without a metering capability
may receive power values from one or more PMs and PIs in inlet mode.
For controlling PIs it may be difficult to find out where control
capabilities are available and which PEs would be affected by
switching an PI in outlet mode at a PS.
Most of these problems can be resolved by the availability of power
supply topology information. The information model for PIs described
in the following section reflects the need for topology detection by
offering information elements for each PI that identify other PEs
that are connected to the same power transmission medium. How this
information is obtained remains an open issue. In case of Power over
Ethernet (PoE), devices may detect the device at the other end of the
line via the coupled Ethernet connection. Other information may have
been entered manually when setting up devices, or automatically
determined through other means.
3.4. Energy management information model
This section specifies an information model for monitoring entities
and Power Interfaces (PIs). It addresses the issues discussed in the
previous sections and meets all the requirements for energy
management specified in [I-D.ietf-eman-requirements]. except for the
reporting of time series of energy and power values. But these can
easily be added.
The model assumes that there is a given mechanism to identify managed
entities by a network management system and that this mechanism uses
a sufficiently unique entity identifier (EID). Then the information
model for PIs is specified by the diagram in Figure 3.
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+---------------------------------+
| ManagedEntity | +-----------------+
+---------------------------------+ | PowerState |
| EID | 1 +-----------------+
| Type | . | Number |
| Tags | . | Description |
| | 1 N | MaxPower |
| PowerStates |----- | AveragePower |
| ActualStateSet | | TimeInState |
| ActualState | | LastTimeInState |
+---------------------------------+ | TimesEntered |
1 | | TotalEnergy |
| +-----------------+
0..N |
+---------------------------------+
| PowerInterface |
+---------------------------------+
| Index | 0 +-----------------+
| Tags (for grouping) | . | PiId |
| Mode (inlet,outlet) | . +-----------------+
| MeteringCapability | 1 N | EID |
| ConnectedTo (PIs of others) |------| PI Index |
| TypeOfCurrent (AC,DC) | +-----------------+
| NominalVoltage |
| NominalAcFrequency |
| NumberOfAcPhases |
| ControlCapability (switch) |
| | +-----------------+
| PowerAvaialbility (on,off) | | Phase |
| InUse (current>0) | +-----------------+
| RealPower | 1 | PowerFactor |
| PowerMeasurementInterval | . | ActualVoltage |
| PowerMeasurementConfidence | . | ActualFrequency |
| PowerMeasurementAccuracy | 1 3 | TotalHarmonic- |
| Phases |------| Distortion |
| | | SupplyImpedance |
| TotalEnergy | +-----------------+
+---------------------------------+
Figure 3: Information model for energy management
We further assume that existing mechanisms for reporting values on
behalf of other entities or devices are sufficient for meeting
requirements in Sections 7 and 8 of [I-D.ietf-eman-requirements].
The information model in Figure 3 contains five kinds of objects.
The ManagedEntity object contains attributes describing the monitored
entity. Instances of class PowerState describe a single power state
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of the managed entity. PIs are described by PowerInterface objects.
Instances of class PiId identify PIs of other managed entities
connected to the same power transmission medium and can be used for
describing the power supply topology. Objects Phase are used for
representing actual power quality values. For DC current only one
object is required per PI, for AC current up to three objects may be
needed.
4. Security Considerations
This memo currently does not impose any security considerations.
5. IANA Considerations
This memo has no actions for IANA..
6. Acknowledgements
This memo was inspired by discussions with Benoit Claise, John
Parello, Mouli Chandramouli, Rolf Winter, Thomas Dietz, Bill Mielke,
and Chris Verges.
7. Open Issues
7.1. Change mode from inlet to outlet?
Is it needed to support a PI to be in mode "inlet" to be able to
change to mode "outlet" and back?
7.2. Collector and Aggregator
It looks like we need to extend the model by a collector function and
an aggregator function. A collector would collect energy-related
information on other devices and report for multiple of them. An
aggregator would use information from several devices and excecute
operations on them, for example calculating a sum.
8. Informative References
[I-D.ietf-eman-requirements]
Quittek, J., Winter, R., Dietz, T., Claise, B., and M.
Chandramouli, "Requirements for Energy Management",
draft-ietf-eman-requirements-03 (work in progress),
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June 2011.
[I-D.ietf-eman-framework]
Claise, B., Parello, J., Silver, L., and J. Quittek,
"Energy Management Framework",
draft-ietf-eman-framework-02 (work in progress),
July 2011.
[RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410, December 2002.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)",
RFC 6241, June 2011.
[RFC5101] Claise, B., "Specification of the IP Flow Information
Export (IPFIX) Protocol for the Exchange of IP Traffic
Flow Information", RFC 5101, January 2008.
[RFC5675] Marinov, V. and J. Schoenwaelder, "Mapping Simple Network
Management Protocol (SNMP) Notifications to SYSLOG
Messages", RFC 5675, October 2009.
[IEEE-802.3af]
IEEE 802.3 Working Group, "IEEE Std 802.3af-2003 - 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)", July 2003.
[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.
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Appendix A. Energy Monitoring Reference Model Version -01
This appendix specifies the previous version -01 of the reference
model for energy monitoring. After introducing basic concepts of
energy monitoring in Appendix A.1 it defines entities of the model
and their interactions in Appendix A.2. Examples of devices and
scenarios are illustrated in Appendix A.5.
A.1. Introduction to Energy Monitoring
In this section we introduce basic concepts of energy monitoring
starting with the most basic scenario and extending it stepwise to
our full reference model.
The main subject of energy monitoring is a powered device. An energy
monitoring system collects information about powered devices, their
current power state (for example: on, sleep, off) and their actual
power consumption.
A.1.1. Basic Energy Monitoring (local metering)
The most basic interaction in an energy monitoring system is a
powered device directly reporting its own energy-related information,
with no other devices involved, as shown below.
energy monitoring
system
^
|
device
A.1.2. External Metering
Reporting its current power state is a relatively easy task for a
powered device because usually information on the current power state
is locally available at the device and a reporting function just
needs some additional software to implement it.
Reporting the current power level of a device and its accumulated
energy consumption is a harder task, particularly if there are strict
requirements for accuracy. Today very few devices are instrumented
with means for measuring their own energy consumption as that usually
implies adding hardware for this purpose.
This can be addressed by external meters, that is, dedicated probes
that can meter energy consumption on a power source (line). Some
Power Distributions Units (PDUs) and Power over Ethernet (PoE)
[IEEE-802.3af] switches integrate power source and power metering for
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individual devices.
For supporting scenarios with external meters we extend the basic
model from above by an external power meter and a power source as
shown below.
energy monitoring system
^ ^ ^
| | |
power power powered
source meter device
###############
symbols ######### represent a power supply line
All three potentially report to the energy monitoring system. The
power meter may report the current power and accumulated energy
consumption and the power source may report if the power supply for
the device is switched on or if it is off.
Implementation may be incomplete. For example, an energy management
system may have access to only one or two of these three types of
data.
A.1.3. Functions and Entities
This reference model operates at two levels/layers. One is simple
basic functions that are implemented. The second is how they are
arranged in devices. A device in this model may implement only a
single function, or may implement many.
That is, having multiple entities does not require that all of them
need to be instantiated by individual devices. For example, the
power meter function may be co-located and integrated with the
powered device, with the power source, or it may be implemented by a
separate device.
A.1.4. Power Monitors
In the models above, the powered device and other components deliver
reports directly to an energy monitoring system. However, there are
energy monitoring scenarios where this is not possible or not
desirable.
Extreme examples are energy consumers that do not have IP interfaces
but can communicate by other means. For delivering their reports to
an IP-based energy monitoring system, it may be required to use a
gateway that can communicate with the energy monitoring system.
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However, even if all involved devices (PDUs, power meters, and
powered devices) can communicate via IP, it may be desirable to have
mediation functions in place between powered devices and the energy
monitoring system. An example, is an aggregating device that
aggregates and reports information on several powered devices.
There are several further useful scenarios. To generalize the model
(and to not exclude any kind of gateway, proxy, relay, mediator or
other device) we define reporting entities called 'monitors'. The
figure below shows three monitors, each of which reports to the
energy monitoring system. This figure is the most generic
representation of the energy monitoring reference model described by
this document.
Energy Monitoring Reference Model
+-------------------------------------------------------------------+
| energy monitoring system |
+-------------------------------------------------------------------+
^ ^ ^
| | |
+-------------------+ +-------------------+ +-------------------+
| power source | | power usage | | power state |
| monitor | | monitor | | monitor |
+-------------------+ +-------------------+ +-------------------+
| | |
+-------------------+ +-------------------+ +-------------------+
| power | | power meter | | powered |
| source | +-------------------+ | device |
+-------------------+###########################+-------------------+
symbols ######### represent a power supply line
A monitor function reports directly to the energy monitoring system
using the EMON protocol (an Internet protocol). A monitor must have
means to acquire the information it reports, but how this information
is acquired is not relevant for our model. That is, only the
interactions with a caret symbol in this and following diagrams is
the subject of standardization. Those with only the vertical bar
character are outside the scope of these documents; they may be IP or
non-IP.
The reference model defines the communication between power monitors
an the energy monitoring system. The communication lines between
these entities are reference points of our model described in more
detail in the following.
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A.2. Energy Monitoring Entities
This section defines entities of the energy monitoring reference
model and describes interactions between them. Examples scenarios
are illustrated in Appendix A.5.
A.2.1. Powered Device
A powered device is provided with energy (typically electrical)
usuallly provided via power lines. Power state, power and consumed
energy of powered devices are subject to monitoring and control
functions of energy management.
A.2.2. Power Source
A power source provides a powered device with energy, typically via a
power line. It may have means to switch on and off the power for the
powered device. A power source does not necessarily generate power,
but it may do so. It may be as simple as a power switch or a power
plug, but it may also be a battery or a power generator. Regardless,
the nature of the source does not affect energy monitoring.
Note that an internal battery within a device, such as the battery of
a notebook PC or of a mobile phone are not considered to be a power
source. When a device runs on battery only, there is n flow of
energy into the device and consequently the power to be reported for
this device is zero. On the other hand, when a device charges its
battery, then the power supplied for charging needs to be accounted,
even if the device is not operational.
A.2.3. Power Meter
A power meter measures power and/or consumed energy, and typically is
electrically connected to power supply lines for powered devices.
However, many devices can also provide a reliable estimate of their
power consumption based on internal status information without having
dedicated metering hardware. Regardless, all metering information is
qualified by an indication of its accuracy.
The meter function also includes integrating power consumption over
time to provide a "meter reading" with a time stamp to enable an
energy monitoring system to track energy consumption over time.
A.2.4. Power Monitors
A power monitor has access to energy-related information concerning
powered devices and is able to report this information to energy
management systems.
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A power monitor may also provide information on identity and
properties of a powered device to the management system.
A power monitor may store energy-related information and process it,
for example, for aggregating information or for extracting statistics
that are provided to an energy management system.
There are three power monitor functions in the energy monitoring
reference model: power state monitors, power source monitors, and
power usage monitors.
A.2.4.1. Power State Monitor
A power state monitor has access to the power state of a powered
device and is able to report this information to an energy monitoring
system. For acquiring power state information it may interact with
powered devices.
A.2.4.2. Power Source Monitor
A power state monitor has access to information on the power supply
of powered devices and is able to report this information to an
energy monitoring system. Typically, it will just report either 'on'
or 'off'. In addition, it may report on power availability. For
acquiring power source information it may interact with the power
sources of powered devices.
A.2.4.3. Power Usage Monitor
A power usage monitor has access to information on energy consumption
of powered devices and is able to report this information to energy
management systems. For acquiring information on energy consumption
it may interact with power meters.
A.2.5. Energy Monitoring System
An energy monitoring system receives information from power monitors,
such as: power states, power source states, and energy consumption.
An energy monitoring system may be centralized or distributed. In
most of the example scenarios illustrated in Appendix A.5 a
centralized energy monitoring system is shown but in all cases can be
replaced by a distributed monitoring system.
A.3. Standardization Scope
The reference model specifies interactions of an energy monitoring
system with power monitors. They reference points of the model are
potential subjects of standardization (in the EMAN working group).
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Interactions of power monitors with other entities are currently not
considered to be subject of standardization.
It is argued in [I-D.ietf-eman-requirements] that for most of the
relevant scenarios the best choice a management protocol for the
reference points is SNMP [RFC3410]. The reference model defined in
this document does not assume a specific protocol between energy
monitoring system and power monitors. It is also applicable if other
protocols, such as, for example, Syslog [RFC5675] or IPFIX [RFC5101]
are used.
A.4. Entity Relationships
No restrictions on entity relationships have been identified for
interacting entities of the energy monitoring reference model
specified in this document. This means that all relationships
between entities may be one-to-one, one-to-many, many-to-one, or
many-to-many. For example,
o a single power state monitor may report the power state of
multiples powered entities,
o a single powered entity may have its power states reported by<
multiple power state monitors,
o a single powered device may receive power from several power
sources,
o a single power monitor may report to multiple energy monitoring
systems.
A few of scenarios with multiple instances of units are illustrated
by the examples in the following Appendix A.5.
A.5. Energy Monitoring Scenarios
This section describes common example scenarios for energy monitoring
and how they are modeled with the entities and interactions described
in the previous sections.
A.5.1. Simple Device with Power Meter
A very basic example is a powered device that has a built-in meter
for measuring its own energy consumption and that reports its power
state and power usage directly to the energy monitoring system.
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+-------------------------------------------------------------------+
| energy monitoring system |
+-------------------------------------------------------------------+
^
|
+-----------------------------------------------+
| | |
| +-----------+-----------+ |
| | | |
| +-------------------+ +-------------------+ |
| | power usage | | power state | |
| | monitor | | monitor | |
| +-------------------+ +-------------------+ |
| | | |
+-----------------+ | +-------------------+ +-------------------+ |
| power | | | power meter | | powered | |
| source | | +---------#---------+ | device | |
+-----------------+#|#########################+-------------------+ |
| |
| powered device with meter and power monitors |
+-----------------------------------------------+
Scenario 1: Powered device metering and self-reporting
Here four entities are combined in a single device: the powered
device, the power meter, and two power monitors.
A.5.2. External Power Meter
The second example shows a power meter that is attached to the power
line of a powered device that does not have means for measuring its
own energy consumption. The meter is integrated with a power usage
monitor that reports metered data. The powered device may report its
own power state by an integrated power state monitor.
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+-------------------------------------------------------------------+
| energy monitoring system |
+-------------------------------------------------------------------+
^
|
+-----------------------+
| external | meter |
| +-------------------+ |
| | power usage | |
| | monitor | |
| +-------------------+ |
| | |
| +-------------------+ |
+-----------------+ | | power meter | | +-------------------+
| power | | +---------#---------+ | | powered |
| source | +-----------#-----------+ | device |
+-----------------+#############################+-------------------+
Scenario 2: An external meter
A.5.3. External Power Meter for Multiple Powered Devices
Power meters may be located at a power line that provides power for
multiple powered devices. In scenario 3, a single power meter
measures the accumulated power and energy consumption of multiple
powered devices. In general, In this scenario it is usually not
possible to derive power values for the individual powered devices
from the accumulated measurement.
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+-------------------------------------------------------------------+
| energy monitoring system |
+-------------------------------------------------------------------+
^
|
+-----------------------+
| external | meter |
| +-------------------+ |
| | power usage | | +----------------+
| | monitor | | | powered |
| +-------------------+ | | device |
| | | ###+----------------+
| +-------------------+ | #
+-----------------+ | | power meter | | # +----------------+
| power | | +---------#---------+ | # | powered |
| source | +-----------#-----------+ # | device |
+-----------------+################################+----------------+
#
# +----------------+
# | powered |
# | device |
###+----------------+
Scenario 3: An external meter for multiple powered devices
A.5.4. Powered Device with Dual Power Supply
Some powered devices have dual power supply. It may be that one
supply comes from a power grid and the other one from a battery.
High-reliability devices may have two power sources from different
power distribution networks, as shown in scenarios 4 and 5.
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+-------------------------------------------------------------------+
| energy monitoring system |
+-------------------------------------------------------------------+
^
|
+-----------------------------------------+
| | |
| +-------------------------------------+ |
| | power usage monitor | |
| +-------------------------------------+ |
| | | |
| +---------+ +-----------+ +---------+ |
+---------+ | | power | | powered | | power | | +---------+
| power | | | meter | | device | | meter | | | power |
| source | | +----#----+ | | +----#----+ | | source |
+---------+##|##############+-----------+##############|##+---------+
| |
| powered device with dual power supply |
| and dual metering |
+-----------------------------------------+
Scenario 4: powered device with dual power supply
In scenario 4 the device uses two meters, one for each power line and
reports from both to the energy monitoring system. If the two power
sources belong to different power distribution domains, it may be
necessary to report power and energy separately for each supply.
A.5.5. Two energy monitoring systems
Scenario 5 is more complex. Both meters are individual external
devices and there are even two separate energy monitoring systems
involved, one for each power distribution tree.
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+-------------------------------+ +-------------------------------+
| energy monitoring system | | energy monitoring system |
+-------------------------------+ +-------------------------------+
^ ^
| |
+-----------+ +-----------+
| | | | | |
| +-------+ | | +-------+ |
| |power | | | |power | |
| |usage | | | |usage | |
| |monitor| | | |monitor| |
| +-------+ | | +-------+ |
| | | | | |
| +-------+ | | +-------+ |
| | power | | | | power | |
+--------+ | | meter | | +-------------+ | | meter | | +--------+
| power | | +---#---+ | | powered | | +---#---+ | | power |
| source | +-----#-----+ | device | +-----#-----+ | source |
+--------+#################+-------------+#################+--------+
Scenario 5: powered device with dual power supply
from different power distribution trees
A.5.6. Power over Ethernet Switch
This example shows a Power over Ethernet (PoE) [IEEE-802.3af] switch
supplying a powered device. The switch contains a power source and a
meter for each of its ports.
There typically are multiple instances of power sources and power
meters in a PoE switch, but the drawing below shows only a single
instance. The same applies to the powered devices that are
represented by a single instance only.
Note that a typical PoE switch has also means to control power supply
for powered devices (not shown here). Control of power supply is a
subject of Appendix B.
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+-------------------------------------------------------------------+
| energy monitoring system |
+-------------------------------------------------------------------+
^
|
+---------------------------------------------+
| | |
| +----------+-----------+ |
| | | |
| +-----------------+ +-------------------+ |
| | power source | | power usage | |
| | monitor | | monitor | |
| +-----------------+ +-------------------+ |
| | | |
| +-----------------+ +-------------------+ | +-------------------+
| | power | | power meter | | | powered |
| | source | +---------#---------+ | | device |
| +-----------------+#########################|#+-------------------+
| |
| Power over Ethernet switch |
| or Power Distribution Unit |
+---------------------------------------------+
Scenarios 6 & 7: Power over Ethernet switch or Power Distribution
Unit reporting on power source and power usage of powered devices
In this scenario the identification of the powered device can be done
by the PoE switch by observing MAC and IP addresses of the powered
devices. The switch can report them to the energy management system
which then in turn can contact the devices directly to obtain further
information.
A.5.7. Power Distribution Unit
The same figure as used for the PoE switch in the previous section is
be used for scenario 7 modeling a power distribution unit (PDU). A
PDU with meters for every socket can report power for each.
Identifying the powered devices can more difficult in this scenario
than in the previous one with the PoE switch, because the PDU does
not necessarily communicate with the powered devices. In this case
the PDU or EMS needs to obtain this information by other means, for
example by manual configuration.
A.5.8. Aggregator
Scenario 8 shows a power usage monitor acting as an aggregator. It
collects power information from three powered devices and delivers
all of the information to the energy monitoring system. The
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aggregator may deliver the full information or aggregated
information, for example, just the sum of the power of all three
powered devices.
+-------------------------------------------------------------------+
| energy monitoring system |
+-------------------------------------------------------------------+
^
|
+-------------------------------------------------------------------+
| power usage monitor |
+-------------------------------------------------------------------+
| | |
+-------------------+ +-------------------+ +-------------------+
| | | | | | | | |
|+-------+ +-------+| |+-------+ +-------+| |+-------+ +-------+|
|| power | |powered|| || power | |powered|| || power | |powered||
|| meter | |device || || meter | |device || || meter | |device ||
|+-------##+-------+| |+-------##+-------+| |+-------##+-------+|
+--------#----------+ +--------#----------+ +--------#----------+
# # #
+-------------------------------------------------------------------+
| power source |
+-------------------------------------------------------------------+
Scenario 8: An aggregator collecting monitoring information
from three powered devices
A.5.9. Energy Monitoring Gateway
Some energy monitoring scenarios include a gateway between the
monitored units and the energy monitoring system. The powered device
and the power meter may use means of communication other than IP.
The gateway is a relay and protocol converter that delivers energy
information to a power monitor. A single device may implement
logically independent gateways for multiple devices.
Scenario 9 can easily extended to a gateway that also contains a
power source monitor.
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+-------------------------------------------------------------------+
| energy monitoring system |
+-------------------------------------------------------------------+
^
|
+---------------------------------------------+
| | |
| +-----------+----------+ |
| | | |
| +-------------------+ +-----------------+ |
| | power usage | | power state | |
| | monitor | | monitor | |
| +-------------------+ +-----------------+ |
| gateway | | |
+---------------------------------------------+
| |
+-------------------+ +-------------------+ +-----------------+
| power | | power meter | | powered |
| source | +---------#---------+ | device |
+-------------------+###########################+-----------------+
Scenario 9: A gateway between monitored devices
and energy monitoring system
Here again, the problem of identifying the powered device has become
very difficult, because neither can the power monitor provide an IP
address of the powered device to the energy management system nor can
the energy management system directly communicate with the powered
device. Identification must be provided by other means. The Proxy
can have a gateway function and relay identification between powered
device and energy management system or the energy management system
needs to acquire information on powered devices by other means, such
as manual configuration.
A.5.10. Further Scenarios
More scenarios may be added to future versions of this document.
Particularly, scenarios with multiple instances of an entity have not
been elaborated a lot. Appendix B.4 shows scenarios for energy
control. They can also be considered as further monitoring scenarios
if only their power monitors are considered and power controllers are
ignored.
Appendix B. Energy Management Reference Model version -01
This appendix specifies the previous version -01 of the reference
model for energy management. It extends the energy monitoring
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reference model specified in the previous Appendix A by adding power
control functions. The resulting model is a complete energy
management reference model.
As in Appendix A we first discuss entities and their relationships
and then illustrate the model with example scenarios.
The extension from energy monitoring to energy management is straight
forward. To achieve the required control functions the power source,
power meter, and powered device have additional functions for
control. For each power monitor a corresponding power controller is
added as shown below.
Energy Management Reference Model
+-------------------------------------------------------------------+
| energy management system |
+-------------------------------------------------------------------+
^ | ^ | ^ |
| v | v | v
+--------+ +--------+ +--------+ +--------+ +--------+ +--------+
| power | | power | | power | | power | | power | | power |
| source | | source | | usage | | meter | | state | | state |
| monitor| | ctrler | | monitor| | ctrler | | monitor| | ctrler |
+--------+ +--------+ +--------+ +--------+ +--------+ +--------+
| | | | | |
+-------------------+ +-------------------+ +-------------------+
| power | | power meter | | powered |
| source | +-------------------+ | device |
+-------------------+###########################+-------------------+
symbols ######### represent a power line
B.1. Energy Management Entities
This section defines entities of the energy management reference
model and describes interactions between them. Examples scenarios
are illustrated in Appendix B.4. For entities already specified in
Appendix A.2 of the energy monitoring reference model, only their
additional properties are mentioned here. Power monitors are not
discussed here again, because their specification in the energy
management reference model do not change.
B.1.1. Powered Device
A powered device may be capable of changing its own power state from
a request from the energy management system. Some devices may not be
able to power up from an off state based on EMS request. Most
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devices that are asleep will be able to wake on EMES request.
B.1.2. Power Source
A power source may be capable of switching on and off power for
powered devices.
B.1.3. Power Meter
A power meter may be switched on or off or have its metering
parameters modified.
B.1.4. Power Controllers
A power controller receives commands from an energy management system
to change the status or parameters of power sources, power meters, or
powered devices.
There are three kinds of power controller entities: power state
controllers, power source controllers, and power meter controllers.
B.1.4.1. Power State Controller
A power state controller can initiate a change in the power state of
a powered device.
B.1.4.2. Power Source Controller
A power source controller can change the power supply of a powered
device. Typically, it has means for switching power supply on and
off. It may use these means without communicating with the affected
powered device.
B.1.4.3. Power Meter Controller
A power meter controller has means for influencing the operation of a
power meter. It may switch on and off the power meters and change
parameters of their operation. For this purpose it may interact with
power meters.
B.1.5. Energy Management System
An energy management system is an energy monitoring system extended
by control functions. It interacts with power monitors and power
controllers in order to achieve objectives of energy management.
It sends commands to power controllers. To power state controllers
it sends requested power states for powered devices. To power source
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controllers it requests to switch on or off power for powered
devices. To power meter controllers it sends commands concerning the
operation of power meters.
B.2. Reference Points
Relevant for our reference model are interactions of the energy
management system with power monitors and power controllers. They
are reference points of our model and potential subjects of
standardization in the EMAN working group. Interactions of power
monitors and power controllers with other entities are currently not
considered to be subject of standardization.
Monitoring protocols have already been discussed in Appendix A.3.
There are several choices of control protocols to be used for energy
management. Among them are SNMP [RFC3410] and NETCONF [RFC6241].
B.3. Entity Relationships
The considerations on entity relationships for the energy monitoring
reference model described in Appendix A.4. apply as well to the
energy management reference model: No restrictions on entity
relationships have been identified.
B.4. Energy Management Scenarios
This section describes example scenarios for energy management and
how they are modeled with the entities and interactions described
above.
B.4.1. Simple Self-Managed Device
The first two examples are expected to become very common scenarios.
Here, a powered device is managing its power state on its own based
on input other than from the energy management system. The device
may decide to change power state based on observation of its
environment (no current load, high temperature, not sufficient light,
scheduled time for service interruption, etc.) or it may receive
external triggers, such as by a human-operated remote control.
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+-------------------------------------------------------------------+
| energy management system |
+-------------------------------------------------------------------+
^
|
+-----------------------+
| | |
| +--------+ +--------+ |
| | power | | power | |
| | state | | state | |
| | monitor| | ctrler | |
| +--------+ +--------+ |
| | | |
+-----------------+ | +-------------------+ |
| power | | | powered | |
| source | | | device | |
+-----------------+#|#########################+-------------------+ |
| |
| powered device with |
| power state control |
+-----------------------+
Scenario 10: A self-managed powered device
In any way, it's power state control is independent of the energy
management system. The only interaction with the system is reporting
of power state to the energy management system in scenario 10, and in
addition reporting of its current power and/or accumulated consumed
energy in scenario 11.
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+-------------------------------------------------------------------+
| energy management system |
+-------------------------------------------------------------------+
^
|
+-----------------------------------------------+
| | |
| +-----------------+-----+ |
| | | |
| +--------+ +--------+ +--------+ +--------+ |
| | power | | power | | power | | power | |
| | usage | | meter | | state | | state | |
| | monitor| | ctrler | | monitor| | ctrler | |
| +--------+ +--------+ +--------+ +--------+ |
| | | | | |
+-----------------+ | +-------------------+ +-------------------+ |
| power | | | power meter | | powered | |
| source | | +---------#---------+ | device | |
+-----------------+#|#########################+-------------------+ |
| |
| powered device with built-in meter |
| and autonomous control |
+-----------------------------------------------+
Scenario 11: A self-managed powered device with built-in meter
In scenario 11 also the control of the power meter is handled by the
device itself.
B.4.2. Simple Managed Device
In our model, the scenario does not change much if the powered
devices are not self-managed but managed by the energy management
system. Scenarios 12 and 13 show that just an interaction between
the energy management system and the powered device is added that
serves for sending commands concerning power states to the device.
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+-------------------------------------------------------------------+
| energy management system |
+-------------------------------------------------------------------+
^ |
| |
+-----------------------+
| | v |
| +--------+ +--------+ |
| | power | | power | |
| | state | | state | |
| | monitor| | ctrler | |
| +--------+ +--------+ |
| | | |
+-----------------+ | +-------------------+ |
| power | | | powered | |
| source | | | device | |
+-----------------+#########################|#+-------------------+ |
| |
| powered device with |
| power state control |
+-----------------------+
Scenario 12: A managed powered device
Control of the power meter by the management system can easily added
to scenario 13. It is not included here, because for built-in meters
this seems not to be necessary in many common cases.
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+-------------------------------------------------------------------+
| energy management system |
+-------------------------------------------------------------------+
^ |
| |
+-----------------------------------------------+
| | | |
| +-----------------+-----+ | |
| | | v |
| +--------+ +--------+ +--------+ +--------+ |
| | power | | power | | power | | power | |
| | usage | | meter | | state | | state | |
| | monitor| | ctrler | | monitor| | ctrler | |
| +--------+ +--------+ +--------+ +--------+ |
| | | | | |
+-----------------+ | +-------------------+ +-------------------+ |
| power | | | power meter | | powered | |
| source | | +---------#---------+ | device | |
+-----------------+#|#########################+-------------------+ |
| |
| powered device with built-in meter |
| and autonomous control |
+-----------------------------------------------+
Scenario 13: A managed powered device with built-in meter
B.4.3. Power over Ethernet Switch
Scenario 14 adds control functions to the PoE switch of scenario 6 in
Appendix A.5. Here the energy management system can explicitly
request the power for a powered device to be switched on or off. It
also can switch on and off metering and reporting of energy
consumption per port of the switch
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+-------------------------------------------------------------------+
| energy management system |
+-------------------------------------------------------------------+
| ^ | ^
| | | |
+-------------------------------------------+ +---------------------+
| | | | | | | |
| +----------------+----+ | | | | |
| | v | v | | | |
|+--------+ +--------+ +--------+ +--------+| |+--------+ +--------+|
|| power | | power | | power | | power || || power | | power ||
|| source | | source | | usage | | meter || || state | | state ||
|| monitor| | ctrler | | monitor| | ctrler || || monitor| | ctrler ||
|+--------+ +--------+ +--------+ +--------+| |+--------+ +--------+|
| | | | | | | | | |
|+-------------------+ +-------------------+| |+-------------------+|
|| power | | power meter || || powered ||
|| source | +---------#---------+| || device ||
|+-------------------+######################|#|+-------------------+|
| | | |
| Power over Ethernet switch | | powered device with |
| or Power Distribution Unit | | power state control |
+-------------------------------------------+ +---------------------+
Scenario 14 & 15: Power over Ethernet switch
or Power Distribution Unit
Still, the powered device in this scenario is self-managed
controlling its power state on its own and just reporting it to the
energy management system.
B.4.4. Power Distribution Unit
Again, as in Appendix A.5 the scenario for a power distribution unit
looks exactly the same in our reference model as the scenario for a
power distribution unit.
B.4.5. Energy Management Gateway
Starting from an energy monitoring gateway in Appendix A.5 the
extension towards an energy management gateway is again straight
forward.
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+-------------------------------------------------------------------+
| energy management system |
+-------------------------------------------------------------------+
| ^ |
| | |
+-----------------------------------------------+
| | | | |
| +-----------------+-----+ | |
| | gateway v | v |
| +--------+ +--------+ +--------+ +--------+ |
| | power | | power | | power | | power | |
| | usage | | meter | | state | | state | |
| | monitor| | ctrler | | monitor| | ctrler | |
| +--------+ +--------+ +--------+ +--------+ |
| | | | | |
+-----------------------------------------------+
| | | |
+-----------------+ +-------------------+ +-------------------+
| power | | power meter | | powered |
| source | +---------#---------+ | device |
+-----------------+###########################+-------------------+
Scenario 16: A gateway between powered devices
and energy monitoring system
Here again, the problem of identifying the powered device has become
very difficult, because neither can the power monitor provide an IP
address of the powered device to the energy management system nor can
the energy management system directly communicate with the powered
device. Identification must be provided by other means. The Proxy
can have a gateway function and relay identification between powered
device and energy management system or the energy management system
needs to acquire information on powered devices by other means, such
as manual configuration.
B.4.6. Further Scenarios
More scenarios may be added to future versions of this document.
Particularly, scenarios with multiple instances of an entity have not
been elaborated, yet. Appendix B.4 shows scenarios for energy
control. They can also be considered as further monitoring scenarios
if only their power monitors are considered and power controllers are
ignored.
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Authors' Addresses
Juergen Quittek
NEC Europe Ltd.
Network Research Division
Kurfuersten-Anlage 36
Heidelberg 69115
DE
Phone: +49 6221 4342-115
Email: quittek@neclab.eu
Bruce Nordman
Lawrence Berkeley National Laboratory
1 Cyclotron Road
Berkeley 94720
US
Phone: +1 510 486 7089
Email: bnordman@lbl.gov
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