One document matched: draft-norwin-energy-consider-02.txt
Differences from draft-norwin-energy-consider-01.txt
Network Working Group B. Nordman
Internet-Draft Lawrence Berkeley National
Intended status: Informational Laboratory
Expires: September 16, 2011 R. Winter
NEC Labs Europe
March 15, 2011
Considerations for Power and Energy Management
draft-norwin-energy-consider-02
Abstract
With rising cost and an increasing awareness of the environmental
impact of energy consumption, a desirable feature of networked
devices is to be able to assess their power state and energy
consumption at will. With this data available, one can build
sophisticated applications such as monitoring applications or even
active energy management systems. These systems themselves are out
of scope of this memo, as it discusses only considerations for the
monitored devices. Implementation specifics such as the definition
of a Management Information Base are also outside the scope of this
document.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 16, 2011.
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
Nordman & Winter Expires September 16, 2011 [Page 1]
Internet-Draft Consider Energy March 2011
(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.
Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3
2. Overview/Goals . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Settled topics . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Scope of Devices . . . . . . . . . . . . . . . . . . . . . 5
3.2. Identity . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Power Levels . . . . . . . . . . . . . . . . . . . . . . . 5
3.4. Devices . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.5. Intervals . . . . . . . . . . . . . . . . . . . . . . . . 6
3.6. Presentation to non-IETF audiences . . . . . . . . . . . . 6
3.7. Functions vs. Entities . . . . . . . . . . . . . . . . . . 6
3.8. Simple and Complex Devices . . . . . . . . . . . . . . . . 6
4. Topics under discussion . . . . . . . . . . . . . . . . . . . 7
4.1. Power States . . . . . . . . . . . . . . . . . . . . . . . 7
5. Energy Manangement . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Control . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2. Identity . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.3. NMS Considerations . . . . . . . . . . . . . . . . . . . . 9
5.4. MIB Considerations . . . . . . . . . . . . . . . . . . . . 9
5.5. Power Considerations . . . . . . . . . . . . . . . . . . . 10
5.6. Incomplete data . . . . . . . . . . . . . . . . . . . . . 10
5.7. Time reporting . . . . . . . . . . . . . . . . . . . . . . 10
5.8. Portable devices . . . . . . . . . . . . . . . . . . . . . 10
5.9. Beyond energy . . . . . . . . . . . . . . . . . . . . . . 11
5.10. Power State Monitoring . . . . . . . . . . . . . . . . . . 11
5.11. Power Distribution . . . . . . . . . . . . . . . . . . . . 11
6. Use Context and Use Cases . . . . . . . . . . . . . . . . . . 12
7. Future Directions . . . . . . . . . . . . . . . . . . . . . . 13
8. Security Considerations . . . . . . . . . . . . . . . . . . . 14
9. Normative References . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
Nordman & Winter Expires September 16, 2011 [Page 2]
Internet-Draft Consider Energy March 2011
1. Requirements notation
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 [RFC2119].
Nordman & Winter Expires September 16, 2011 [Page 3]
Internet-Draft Consider Energy March 2011
2. Overview/Goals
This document aims at framing discussions on power and energy
management within the IETF and recording their results. It clarifies
terminology that is routinely used to have multiple contrary
meanings, which results in unnecessary confusion. The document
further describes how energy and power reporting differs from other
reporting tasks that have been defined by the IETF and the resulting
implications for mechanisms the IETF will define. This document is
intended to be a living document that also captures why certain
decisions were made in the process of defining power and energy
management mechanisms.
Nordman & Winter Expires September 16, 2011 [Page 4]
Internet-Draft Consider Energy March 2011
3. Settled topics
The following are topics that seem settled in eman discussions,
recognizing that this draft has no authority on that point.
3.1. Scope of Devices
All energy-using devices that have a network connection are in scope.
The eman mechanisms also provide for non-IP devices that are supplied
with power or that have power metered by an IP device, or are brought
into the eman context by a gateway/proxy.
While first adopters will surely be devices such as switches,
routers, and servers (some of which already report power levels and
power state through proprietary means), in the future networked
electronic devices, appliances, and even lights will also need such
capability. These devices may have different ways of accomplishing
discovery and management for functional purposes, but will share the
common energy and power reporting capability. While some devices
will directly measure power, other devices will not be able to
measure their power, but may be able to reliably estimate it. These
devices are still in scope.
3.2. Identity
Some universal mechanisms for identity are needed so that the NMS
knows what the devices are that are using energy. The nature of
these mechanisms, whether they are existing ones to be referenced or
new ones to be created (almost certainly some of both) has not yet
been determined.
3.3. Power Levels
The power level of a device is its current electricity demand. It is
an important complement to power mode, providing articulation of
power level within the basic mode. It also avoids the need for a
large number of named modes. Basic modes are distinguished by
important functional differences or power levels. Core power modes
are an abstraction from individual implementations.
3.4. Devices
The organizing unit for power is a single device with one or more
power sources. The term "product" is sometimes used as a synonym,
and also covers the case in which a device proxies network presence
including power reporting for a second device.
Nordman & Winter Expires September 16, 2011 [Page 5]
Internet-Draft Consider Energy March 2011
3.5. Intervals
A common feature of energy monitoring is to track energy use over
time. Recording of energy use for intervals of time is the
responsibility of a network management system (or whatever entity
requests data via the eman protocol), not the monitored device
itself. The monitored device always reports accumulated energy use
with an associated timestamp.
3.6. Presentation to non-IETF audiences
Many people and organizations who have not in the past understood or
interacted with the IETF will be interested in eman results. They
need to be provided with easily understandable explanations of what
eman does and why. How this presentation will be accomplished is
still to be determined.
3.7. Functions vs. Entities
Eman is concerned with exposing information to Network Management
Systems (NMSs). Providing information is a function. The various
functions may be implemented by a single device, or distributed among
several devices.
3.8. Simple and Complex Devices
We will support both. Simple devices want to avoid complexity that
burdens both implementation on the monitored device, and the
monitoring system. Complex devices need to have access to additional
data fields and capabilities.
Nordman & Winter Expires September 16, 2011 [Page 6]
Internet-Draft Consider Energy March 2011
4. Topics under discussion
4.1. Power States
We synonymously use the terms Power Mode and Power State; named modes
are general categories only ("buckets"), not individual states with
highly-specific meaning.
Discussions about energy consumptions and device power states are
often confusing as different products define states such as "standby"
quite differently. Even the same class of devices often implement
named states differently. Named power states are intrinsically
difficult to define consistently as they imply not only something
about a device's energy consumption but also something about the
device's capabilities in that state, and are implementation-
dependent. All of this makes highly-specific named modes unsuitable
for use in a general context. The term with by far the most
different definitions is "standby" and so we therefore do not refer
to standby in this document and believe it unsuitable for use in
eman.
We believe that the three named power state categories, on, off and
sleep, are broadly understood. These mode categories may each
contain a large set of power sub-states. A fourth basic power state
of 'ready' may be more appropriate for some devices, particularly
appliances.
In general, devices that are asleep will be able to wake quickly and
will retain network connectivity. Devices that are off usually take
much more time to turn on than the wake time and usually lack network
connectivity. Devices that are on are fully functional but
potentially with reduced performance.
A critical feature of the set of basic power states is that they
should be universally applicable to any device eman is applied to.
This does not mean that each device has every state, but that the
model is sufficiently general that it can be applied to all. When
the level of detail rises, the set of states usually is then
applicable to only certain types of products, and/or to specific
implementations. In addition, these detailed states generally embody
specific functional characteristics of the state, and so are better
embodied in other variables (that may be delivered by an energy
management protocol).
Nordman & Winter Expires September 16, 2011 [Page 7]
Internet-Draft Consider Energy March 2011
5. Energy Manangement
First and foremost, the task of power and energy management is
reporting. While a more active role in energy management is
conceivable by e.g. putting devices into power states based on
policies or other predefined schemes at a network management system
(NMS).
5.1. Control
There should not be an assumption that power state management of
devices is done externally/centrally. Ideally most devices will
manage their own power state, implementing distributed intelligence.
The control function is accomplished separately from power reporting.
A core mechanism many devices will use to manage power consumption is
a price (and price forecast) for electricity.
5.2. Identity
All devices on a network need to expose identity to others. While
some protocols accomplish this for particular applications or
contexts, it is desirable to have a simple universal mechanism. This
is particularly true for devices that may have a fairly limited
degree of participation in the network, such as appliances.
For energy management purposes, the it is important to know "what" a
device is, and "who" it is. Each of these has two parts as follows:
o "Species". This is the fundamental classification that a device
is a member of due to its design and capabilities. This property
is determined by the manufacturer before it is sold. Examples are
server, router, notebook PC, display, TV, refrigerator, light,
etc.
o "Origin". The brand and model of the device. Primarily a method
to find out more information about a device, such as its
specifications for requirements and capabilities. It would be
advantageous to include a URL for detailed information from the
manufacturer. An example of this is the "Universal Product Code"
on many products.
o Name: A human-readable name, locally specified when the device is
configured or installed.
o Network ID: A globally unique identifier for the NMS to use to
recognize a device. This should be based on one or more existing
IETF mechanisms.
Nordman & Winter Expires September 16, 2011 [Page 8]
Internet-Draft Consider Energy March 2011
An energy management application could then obtain current energy use
for a device like a refrigerator, and compare it to what it is
expected to use under normal operation, and alert the building
manager if it is significantly out of range. This also can be used
to quickly inventory energy-using products in a building, and to
summarize by product type where energy is being used.
5.3. NMS Considerations
A Network Management System is an entity which collects energy and
power reporting data and uses it for advanced applications. One such
application correlates energy consumption with other metrics to
display efficiency metrics (like watthours/bit). An NMS can also set
device policies to control larger networked systems such as a data
center.
An NMS will query energy MIB data on a periodic basis, with that
period dictated by its needs, possibly being dynamic. MIBs should
provide an energy "meter reading" to allow computing of energy use
for any period. Thus, the NMS does most of the work to generate time
series energy data, and this minimizes burden on the host and the
complexity of the Power MIB.
The core function of power monitoring is to maintain meters of energy
use and of time in different power states (and through summing, total
energy and time). The second is to be able to report current power
consumption and power state.
5.4. MIB Considerations
The MIB should be generic as there are a large number of devices yet
to come and power states are and will become more diverse.
The MIB should be structured so that the smallest possible set of
values/information is applicable to a large range of devices, can be
implemented efficiently and is extensible to accommodate additional
information objects. As an example, many devices will not be battery
powered but it should be easy to add battery monitoring to the basic
set of energy-related information.
The proposed MIB structures enable reporting on components of
products (e.g. linecards in a chassis) in addition to entire
products. Doing this is not part of the eman charter, so while there
is no reason to preclude the capability, it should not be a
distraction to completing the chartered eman scope.
Nordman & Winter Expires September 16, 2011 [Page 9]
Internet-Draft Consider Energy March 2011
5.5. Power Considerations
Reporting should cover both AC and DC power sources. However, other
types should be provided for, and the type of energy is one of the
reported values. Standard low-voltage DC (e.g. USB, Power over
Ethernet, eMerge) is immediately useful. A core set of values should
be available from any device that implements the Power MIB at all so
that an NMS can quickly obtain and aggregate uniform data for all
devices.
There is a fundamental distinction between supplied power from a
device And input power to a device, notably losses that occur in
transmission, as well as other (possibly unknown) devices that are
also using the power. The effect of internal batteries is not
revealed by the MIB, as it only reports on net power into or out of a
device.
5.6. Incomplete data
Energy reporting will cover a wide variety of information about a
device, its status, and energy usage. Sometimes, particularly for
legacy or non-IP products, this will be incomplete. It is critical
that the fact that some data are missing does not undermine the
ability to report the data that are present.
5.7. Time reporting
At the core of energy reporting is data from energy meters that are
meter readings associated with timestamps. A variety of issues arise
on the meaning of that time.
Without strong syncronization, the NMS and the devices it queries
will have different absolute times. However, the NMS knows when it
asked for each meter reading so can account for this difference.
For some devices, when they are off they will be unable to accumulate
their energy consumption. The fact that some consumption may be
missing needs to be communicated to the NMS. One possibility is to
record the last time that a period of missing energy occurred, and
report that to the NMS.
5.8. Portable devices
Devices that are routinely moved from one building to another (or
even within a building) pose special challenges for energy reporting.
The question arises whether it is the energy into the device, or from
the building, which is dominant. It may be important to record the
time a device most recently changed power domain to ensure that a NMS
Nordman & Winter Expires September 16, 2011 [Page 10]
Internet-Draft Consider Energy March 2011
can correctly account only for energy consumed on its premises.
5.9. Beyond energy
The charter references "energy" but virtually all discussion has been
limited to electricity. Other forms of energy should be included at
some point; we should discuss whether this is readily feasible now,
or needs to be postponed to future work.
5.10. Power State Monitoring
For the device power state, the following information is considered
to be relevant:
o the current state
o the time of (or time since) the last change
o the current real power (energy consumption rate)
o accumulated energy consumption
5.11. Power Distribution
Wired networks enable power distribution that is co-incident with
network Communication. However, many devices will not communicate on
the same Medium that they are powered on, or may lack connectivity
entirely (though with the power provider knowing of their identity).
Devices can report power for another device only if they are the
entity providing the power.
Nordman & Winter Expires September 16, 2011 [Page 11]
Internet-Draft Consider Energy March 2011
6. Use Context and Use Cases
The following are some use contexts that this facility is intended
for. These are not necessarily mutually exclusive, and a device can
report the same data regardless of the context.
o A data center, with a NMS which is integrated with application
functionality, and also manages energy use.
o A commercial building, in which the energy reporting is separate
from any management of devices, and more as background to help
understand building operation (including occupancy) and identify
inefficiencies or equipment failures.
o A house, which shares some of the commercial building
characteristics, but with different management approach and
security concerns.
o A vehicle, which uses the reporting only for automatic management,
not for reporting to the user.
Use cases include a facility manager or an NMS in an automated
fashion:
o Understand costs for billing purposes.
o Assess savings potentials.
o Identify possible device malfunctions.
o Reveal unexpected usage patterns.
o Plan for future capacity needs.
o Understand heat production in a building or space.
o A NMS which deals with draws on current power use to deal with an
actual or potential shortfall in power supply.
Nordman & Winter Expires September 16, 2011 [Page 12]
Internet-Draft Consider Energy March 2011
7. Future Directions
The current effort to create a protocol for energy management is
unlikely to be the last word on the topic. In fact, there are many
directions that need to be explored for potential addition to the
features enabled by this mechanism or others. These include:
o other energy media such as wireless power, non-electric energy
(e.g. natural gas, steam, hot/cold water).
o more features for control.
o other energy-relevant quantities (e.g. temperatures, flow rates).
o other resources (e.g. water).
Nordman & Winter Expires September 16, 2011 [Page 13]
Internet-Draft Consider Energy March 2011
8. Security Considerations
None.
Nordman & Winter Expires September 16, 2011 [Page 14]
Internet-Draft Consider Energy March 2011
9. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Nordman & Winter Expires September 16, 2011 [Page 15]
Internet-Draft Consider Energy March 2011
Authors' Addresses
Bruce Nordman
Lawrence Berkeley National Laboratory
Email: bnordman@lbl.gov
Rolf Winter
NEC Labs Europe
Email: rolf.winter@neclab.eu
Nordman & Winter Expires September 16, 2011 [Page 16]
| PAFTECH AB 2003-2026 | 2026-04-24 10:13:12 |