wdiff rfc6988.original rfc6988.txt

Network Working Group
Internet Engineering Task Force (IETF) J. Quittek, Ed.
Internet-Draft
Request for Comments: 6988 NEC Europe Ltd.
Category: Informational M. Chandramouli
Intended status: Informational
ISSN: 2070-1721 Cisco Systems, Inc.
Expires: November 03, 2013
R. Winter
NEC Europe Ltd.
T. Dietz
NEC Europe Ltd.
B. Claise
Cisco Systems, Inc.
May 02,
September 2013

Requirements for Energy Management
draft-ietf-eman-requirements-14

Abstract

This document defines requirements for standards specifications for
energy management.
Energy Management. The requirements defined in this document concern are
concerned with monitoring functions as well as control functions.
Monitoring functions include identification of identifying energy-managed devices and
their components, as well as monitoring of their power states, power inlets, power
outlets, Power States, Power
Inlets, Power Outlets, actual power (the instantaneous power, as opposed to the
demand, which is an averaged power), power attributes, Power Attributes, received
energy, provided energy, and contained batteries. Control functions
serve for
include such functions as controlling power supply and power state Power State of
energy-managed devices and their components.

This document does not specify the features that must be implemented
by compliant implementations but rather lists features that must be
supported by standards for energy management. Energy Management.

Status of This Memo

This Internet-Draft document is submitted in full conformance with the
provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents not an Internet Standards Track specification; it is
published for informational purposes.

This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a maximum candidate for any level of Internet
Standard; see Section 2 of RFC 5741.

Information about the current status of six months this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained 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 November 03, 2013.
http://www.rfc-editor.org/info/rfc6988.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2
1.1. Conventional Requirements For for Energy Management . . . . . 4 3
1.2. Specific Requirements For for Energy Management . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. General Considerations Related To to Energy Management . . . . . 6
3.1. Power States . . . . . . . . . . . . . . . . . . . . . . 7 6
3.2. Saving Energy Versus versus Maintaining Service Level . . . . . 7
3.3. Local Versus versus Network-Wide Energy Management . . . . . . . 7
3.4. Energy Monitoring Versus versus Energy Saving . . . . . . . . . 8
3.5. Overview Of of Energy Management Requirements . . . . . . . 8
4. Identification Of of Entities . . . . . . . . . . . . . . . . . 9
5. Information On on Entities . . . . . . . . . . . . . . . . . . . 10
5.1. General Information On on Entities . . . . . . . . . . . . . 10
5.2. Power Interfaces . . . . . . . . . . . . . . . . . . . . 11
5.3. Power . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.4. Power State . . . . . . . . . . . . . . . . . . . . . . . 15
5.5. Energy . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.6. Battery State . . . . . . . . . . . . . . . . . . . . . . 18 17
5.7. Time Series Of of Measured Values . . . . . . . . . . . . . 19
6. Control Of of Entities . . . . . . . . . . . . . . . . . . . . . 21 20
7. Reporting On on Other Entities . . . . . . . . . . . . . . . . . 21
8. Controlling Other Entities . . . . . . . . . . . . . . . . . 22
8.1. Controlling Power States Of of Other Entities . . . . . . . 22
8.2. Controlling Power Supply . . . . . . . . . . . . . . . . 23
9. Security Considerations . . . . . . . . . . . . . . . . . . . 23
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25
12.
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
12.1.
11.1. Normative References . . . . . . . . . . . . . . . . . . 25
12.2.
11.2. Informative References . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27

1. Introduction
With rising energy cost costs and with an increasing awareness of the
ecological impact of running information technology equipment, energy
management Energy
Management (EMAN) functions and interfaces are becoming an additional
basic requirement for network management systems and devices
connected to a network.

This document defines requirements for standards specifications for
energy management,
Energy Management, both monitoring functions and control functions.
The main subject of energy management are entities in the network,
i.e. device or one of a device's components, that receive and
provide electric energy. Devices may have an IP address, such as
hosts, routers, and middleboxes, or they are connected indirectly to
the Internet via a proxy with an IP address providing a management
interface for the device. An example are devices in a building
infrastructure using non-IP protocols and a gateway to the Internet.

The main subject of energy management are
Energy Management functions focus mainly on devices and their
components that receive and provide electric electrical energy. Devices may
have an IP address, such
as hosts, routers, and middleboxes, middleboxes may have an IP address or they
might may be
connected indirectly to the Internet via a proxy with an IP address
providing a management interface for the device. An example
are device, for example, devices
in a building infrastructure using non-IP protocols and a gateway to
the Internet.

These requirements concern are concerned with the standards specification
process and not the implementation of specified standards. All
requirements in this document must be reflected by standards
specifications to be developed. However, which of the features
specified by these standards will be mandatory, recommended, or
optional for compliant implementations is to be defined by standards track Standards
Track document(s) and not in this document.

Section 3 elaborates on a set of general needs for energy management. Energy Management.
Requirements for an energy management Energy Management standard are specified in
Sections 4 to through 8.

Sections 4 to through 6 contain conventional requirements specifying
information on entities and control functions.

Sections 7 and 8 contain requirements specific to energy management. Energy Management.
Due to the nature of power supply, some monitoring and control
functions are not conducted by interacting with the entity of
interest,
interest but rather with other entities, for example, entities
upstream in a power distribution tree.

1.1. Conventional Requirements For for Energy Management

The specification of requirements for an energy management Energy Management standard
starts with Section 4 addressing 4, which addresses the identification of entities
and the granularity of reporting of energy-related information. A
standard must support the unique identification of entities,
reporting per entire device, and reporting energy-related information
on individual components of a device or attached devices.

Section 5 specifies requirements related to the monitoring of
entities. This includes general (type, context) information and
specific information on Power States, power inlets, power outlets, Power Inlets, Power Outlets,
power, energy, and batteries. Control The control of Power State and power
supply of by entities is covered by requirements specified in Section 6.

1.2. Specific Requirements For for Energy Management

While the conventional requirements summarized above seem to be all
that would be needed for energy management, Energy Management, there are significant
differences between energy management Energy Management and most well known well-known network
management functions. The most significant difference is the need
for some devices to report on other entities. There are three major
reasons for this.

o For monitoring a particular entity entity, it is not always sufficient to
communicate only with the entity only. that entity. When the entity has no
instrumentation for determining power, it might still be possible
to obtain power values for the entity by via communication with other
entities in its power distribution tree. A simple example is retrieving of this
would be the retrieval of power values from a power meter at the
power line into the entity. Common examples are a A Power Distribution Unit (PDU) and a
Power over Ethernet (PoE) switch. switch are common examples. Both supply
power to other entities at sockets or ports, respectively, and are
often instrumented to measure power per socket or port.

o Similar considerations apply to controlling the power supply of a an
entity which that often needs direct or indirect communications with
another entity upstream in the power distribution tree. Again, a
PDU and a PoE switch are common examples, if they have the
capability to switch power on or off power at their sockets or ports,
respectively.

o Energy management Management often extends beyond entities with IP network
interfaces,
interfaces to non-IP building systems accessed via a gateway
(sometimes called an energy management system Energy Management System or controller).
Requirements in this document do not cover the details of these
networks and energy devices, devices but specify means for opening IP
network management towards them.

These specific issues of energy management and a set of further ones Energy Management, as well as other issues,
are covered by requirements specified in Sections 7 and 8.

The requirements in these sections need a new energy management Energy Management
framework that deals with the specific nature of energy management. Energy Management.
The actual standards documents, such as MIB module specifications,
address conformance by specifying which feature features must, should, or may
be implemented by compliant implementations.

2. Terminology

The terms specified in the terminology section are capitalized
throughout the document; the exceptions are the well-known terms
"energy" and "power". These terms are generic and are used in
generated terms such as "energy-saving", "low-power", etc.

Energy

That which does work or is capable the capacity of doing a system to do work. As used by
electric utilities, it is generally a reference to electrical
energy and is measured in kilo-watt hours kilowatt-hours (kWh) [IEEE-100].

Power

The

Power is the time rate at which Energy energy is emitted, transferred, or
received; power is usually expressed in watts (or in joules per
second) [IEEE-100]. (The term "power" does not refer to the
concept of demand, which is an averaged power value.)

Power Attributes

Measurements are measurements of the electrical electric current, voltage, phase
phase, and frequencies at a given point in an electrical power system.
Reference: Adapted
system (adapted from [IEC60050]

NOTES: 1. [IEC.60050]).

NOTE: Power Attributes is are not intended to be judgmental "judgmental" with
respect to a reference or technical value and are independent of
any usage context.

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 in a
manner appropriate to the nature of the application and the cost
constraints of the organization [ITU-M.3400].

Energy Management System

An Energy Management System is a combination of hardware and
software used to administer a network with the primary purpose
being Energy Management [Fed-Std-1037C]. Management.

Energy Monitoring
Energy Monitoring is a part of Energy Management that deals with
collecting or reading information from network elements and
attached devices and their components to aid in Energy Management.

Energy Control

Energy Control is a part of Energy Management that deals with
controlling energy supply and power state Power State of network elements and elements, as
well as attached devices and their components.

Power Interface

A Power Interface is an interface at which a device is connected
to a Power power transmission medium medium, at which it can in turn receive Power,
power, provide Power, power, or both.

Power Inlet

A Power Inlet is a Power Interface at which a device can receive
Power
power from other devices.

Power Outlet

A Power Outlet is a Power Interface at which a device can provide
Power
power to other devices.

Power State

A Power State is a condition or mode of a device that broadly
characterizes its capabilities, Power power consumption, and
responsiveness to input [IEEE-1621].

3. General Considerations Related To to Energy Management

The basic objective of Energy Management is operating to operate sets of
devices
with using minimal Energy, energy, while maintaining a certain level of
service.
[I-D.ietf-eman-applicability-statement] [EMAN-STATEMENT] presents the applicability of the EMAN
framework to a variety of scenarios, scenarios and also lists use cases and
target devices.

3.1. Power States

Entities can be set to an operational state that results in the
lowest power level that still meets the service level service-level performance
objectives. In principle, there are three basic types of Power
States for an entity or for a whole system:

o full Power State
o sleep state (not functional, functional but immediately available)

o off state (may require significant time to become operational)

In specific devices, the number of Power States and their properties
varies
vary considerably. Simple entities may just have only have the extreme
states, states:
full power Power State and off state. Many devices have three basic Power
States: on, off, and sleep. However, more finely grained Power
States can be implemented. Examples are various operational low
power states
Power States in which a device requires less energy than in the full
power "on" state, but - -- compared to the sleep state - -- is still
operational with reduced performance or functionality.

3.2. Saving Energy Versus versus Maintaining Service Level

One of the objectives of Energy Management is to reduce the Energy energy
consumption. While this objective is clear, the way to attain attaining that goal is
often difficult. In many cases cases, there is no way of reducing to reduce power
without the consequence of a potential service (performance or
capacity) degradation. In this case, a trade-off needs to be made
between service level service-level objectives and energy minimization. In other
cases
cases, a reduction of power can easily be achieved while still
maintaining sufficient service level service-level performance, for example, by
switching entities to lower Power States when higher performance is
not needed.

3.3. Local Versus versus Network-Wide Energy Management

Many Energy saving energy-saving functions are executed locally by an entity; it
monitors its usage and dynamically adapts its Power power according to the
required performance. It may, for example, switch to a sleep state
when it is not in use use, or out outside of scheduled business hours. An
Energy Management System may observe an entity's Power State and
configure its Power saving power-saving policies.

Energy savings can also be achieved with policies implemented by a
network management system that controls Power States of managed
entities. Information about the Power power received and provided by
entities in different Power States may be required in order to set
such policies.
Often Often, this information is acquired best acquired through
monitoring.

Both methods, network-wide

Network-wide and local Energy Management, Management methods both have advantages
and disadvantages disadvantages, and often it is often desirable to combine them.
Central management is often favorable for setting Power States of a
large number of entities at the same time, for example, at the
beginning and end of business hours in a building. Local management
is often preferable for Power saving power-saving measures based on local
observations, such as the high or low functional load of an entity.

3.4. Energy Monitoring Versus versus Energy Saving

Monitoring Energy, Power, energy, power, and Power States alone does not reduce the
Energy
energy needed to run an entity. In fact, it may even increase it
slightly due to monitoring instrumentation that needs Energy. energy.
Reporting measured quantities over the network may also increase
Energy
energy use, though the acquired information may be an essential input
to control loops that save Energy. energy.

Monitoring Energy energy and Power States can also be required for other
purposes
purposes, including:

o investigating Energy saving energy-saving potential

o evaluating the effectiveness of Energy saving energy-saving policies and
measures

o deriving, implementing, and testing Power power management strategies

o accounting for the total Power power received and provided by an entity,
a network, or a service

o predicting an entity's reliability based on Power power usage

o choosing the time of the next maintenance cycle for an entity

3.5. Overview Of of Energy Management Requirements

The following basic management functions are required:

o monitoring Power States

o monitoring Power (Energy power (energy conversion rate)

o monitoring (accumulated) received and provided Energy energy

o monitoring Power attributes Attributes

o setting Power States
Power control is complementary to other Energy savings measures energy-saving measures, such
as low-power electronics, Energy saving energy-saving protocols, energy-efficient
device design (for example, low-power modes for components), and
energy-efficient network architectures. Measurement of received and
provided Energy energy can provide useful data for developing these
technologies.

4. Identification Of of Entities

Entities must be capable of being uniquely identified with within the
context of the management system. This includes entities that are
components of managed devices as well as entire devices.

Entities that report on or control other entities must identify the
entities they report on or control: see Section 7 or Section 8,
respectively, for the detailed requirements.

An entity may be an entire device or a component of it. Examples of
components of interest are a hard drive, a battery, or a line card.
It may be required to be able
The ability to control individual components to save Energy. energy may be
required. For example, server blades can be switched off when the
overall load is low low, or line cards at switches may be powered down at
night.

Identifiers for devices and components are already defined in
standard MIB modules, such as the LLDP Link Layer Discovery Protocol
(LLDP) MIB module [IEEE-802.1AB] and the LLDP-MED Link Layer Discovery
Protocol -- Media Endpoint Discovery (LLDP-MED) MIB module
[ANSI-TIA-1057] for devices devices, and the Entity MIB module [RFC4133] [RFC6933] and
the Power power Ethernet MIB [RFC3621] for components of devices. Energy
Management needs a means to link Energy-
related energy-related information to such
identifiers.

Instrumentation for measuring the received and provided Energy energy of a
device is typically more expensive than instrumentation for
retrieving its Power State. Many devices may provide Power State
information for all individual components separately, while reporting
the received and provided Energy energy only for the entire device.

4.1. Identifying Entities

The standard must provide means for uniquely identifying entities.
Uniqueness must be preserved such that collisions of identities are
avoided at potential receivers of monitored information.

4.2. Persistence Of of Identifiers
The standard must provide means for indicating whether identifiers of
entities are persistent across a re-start restart of the entity.

4.3. Change Of of Identifiers

The standard must provide means to indicate any change of entity
identifiers.

4.4. Using Entity Identifiers Of of Existing MIB Modules

The standard must provide means for re-using reusing entity identifiers from
existing standards standards, including at least the following:

o the entPhysicalIndex in the Entity MIB module [RFC4133] [RFC6933]

o the LldpPortNumber in the LLDP MIB module [IEEE-802.1AB] and in
the LLDP-MED MIB module [ANSI-TIA-1057]

o the pethPsePortIndex and the pethPsePortGroupIndex in the Power
Ethernet MIB [RFC3621]

Generic means for re-using reusing other entity identifiers must be provided.

5. Information On on Entities

This section describes information on entities for which the standard
must provide means for retrieving and reporting.

Required information can be structured into seven groups.
Section 5.1 specifies requirements for general information on
entities, such as type of entity or context information.
Requirements for information on Power Inlets and Power Outlets of
entities are specified in Section 5.2. Monitoring The monitoring of Power power and
Energy
energy is covered by Sections 5.3 and 5.5, respectively. Section 5.4
covers requirements related to entities' Power States. Section 5.6
specifies requirements for monitoring batteries. Finally, the
reporting of time series of values is covered by Section 5.7.

5.1. General Information On on Entities

For Energy Management it may be required to understand Management, understanding the role and context of an entity.
entity may be required. An Energy Management System may aggregate
values of received and provided Energy energy according to a defined
grouping of entities. When controlling and setting Power States States, it
may be helpful to understand the grouping of the entity and role of
an entity in a network, for network. For example, it may be important to exclude
some mission critical mission-critical network devices from being switched to lower
Power
power or even from being switched off.

5.1.1. Type Of of Entity

The standard must provide means to configure, retrieve retrieve, and report a
textual name or a description of an entity.

5.1.2. Context Of An of an Entity

The standard must provide means for retrieving and reporting context
information on entities, for example, tags associated with an entity
that indicate the entity's role.

5.1.3. Significance Of of Entities

The standard must provide means for retrieving and reporting the
significance of entities within its context, for example, how
important the entity is.

5.1.4. Power Priority

The standard must provide means for retrieving and reporting Power power
priorities of entities. Power priorities indicate an order in which
Power States of entities are changed, for example, to lower Power
States for saving Power. power.

5.1.5. Grouping Of of Entities

The standard must provide means for grouping entities. This can be
achieved in multiple ways, for example, by providing means to tag
entities, to assign them to domains, or to assign device types to them.

5.2. Power Interfaces

A Power Interface is an interface at which a device is connected to a
Power
power transmission medium medium, at which it can in turn receive Power, power,
provide
Power, power, or both.

A Power Interface is either an inlet or an outlet. Some Power
Interfaces change over time from being an inlet to being an outlet
and vice versa. However However, most Power Interfaces never change.

Devices have Power Inlets at which they are supplied with electric
Power.
power. Most devices have a single Power Inlet, while some have
multiple inlets. Different Power Inlets on a device are often
connected to separate Power power distribution trees. For Energy
Monitoring, it is useful to retrieve information on the number of
inlets of a device, the availability of Power power at inlets inlets, and which of
them
inlets are actually in use.

Devices can have one or more Power Outlets for supplying other
devices with electric Power. power.

For identifying and potentially controlling the source of Power power
received at an inlet, it may be required to identify identifying the Power Outlet of another device
at which the received Power power is provided. provided may be required.
Analogously, for each outlet outlet, it is of interest to identify the Power
Inlets that receive the Power power provided at a certain outlet. Such
information is also required for constructing the wiring topology of
electrical Power power distribution to devices.

Static properties of each Power Interface are required information
for Energy Management. Static properties include the kind of
electric current (AC or DC), the nominal voltage, the nominal AC
frequency, and the number of AC phases. Note that often the nominal
voltage is often not a single value but a voltage range, such as, for
example, (100V-120V), (100V-240V), (100V-120V,220V-240V).

5.2.1. Lists Of List of Power Interfaces

The standard must provide means for monitoring the list of Power
Interfaces of a device.

5.2.2. Operational Mode Of of Power Interfaces

The standard must provide means for monitoring the operational mode
of a Power Interface Interface, which is either "Power Inlet" or "Power
Outlet".

5.2.3. Corresponding Power Outlet

The standard must provide means for identifying the Power Outlet that
provides the Power power received at a Power Inlet.

5.2.4. Corresponding Power Inlets

The standard must provide means for identifying the list of Power
Inlets that receive the Power power provided at a Power Outlet.

5.2.5. Availability Of of Power

If the Power States allow it, the standard must provide means for
monitoring the availability of Power power at each Power Interface. This
indicates
includes indicating whether a power supply at a Power Interfaces Power supply Interface is
switched on or off.

5.2.6. Use Of of Power
The standard must provide means for monitoring for each Power Interface
if it is actually in actual use. For inlets inlets, this means that the device
actually receives Power power at the inlet. For outlets outlets, this means that Power
power is actually provided from it the outlet to one or more devices.

5.2.7. Type Of current of Current

The standard must provide means for reporting the type of current (AC
or DC) for each Power Interface as well as for a device.

5.2.8. Nominal Voltage Range

The standard must provide means for reporting the nominal voltage
range for each Power Interface.

5.2.9. Nominal AC Frequency

The standard must provide means for reporting the nominal AC
frequency for each Power Interface.

5.2.10. Number Of of AC Phases

The standard must provide means for reporting the number of AC phases
for each Power Interface.

5.3. Power

Power is measured as an instantaneous value or as the average over a
time interval.

Obtaining highly accurate values for Power power and Energy energy may be costly
if it requires dedicated metering hardware. hardware is required. Entities without the
ability to measure with high accuracy their Power and power, received energy,
and provided Energy with
high accuracy energy may just report estimated values, for example example,
based on load monitoring, Power State, or even just the entity type.

Depending on how Power power and Energy energy values are obtained, the confidence
in the a reported value and its accuracy will vary. Entities reporting
such values should qualify the confidence in the reported values and
quantify the accuracy of measurements. For reporting accuracy, the
accuracy classes specified in IEC 62053-21 [IEC.62053-21] and IEC
62053-22 [IEC.62053-22] should be considered.

Further properties of the Power power supplied to a device are also of
interest. Particularly for For AC Power supply, power supply in particular, several Power attributes
Attributes beyond the real Power power are of potential interest to Energy
Management Systems. The set of these properties include the includes the complex
Power
attributes Attributes (apparent power, reactive power, and phase angle of
the current or power factor) as well as the actual voltage, the
actual AC frequency, the Total Harmonic Distortion (THD) of voltage
and current, and the impedance of an AC phase or of the DC supply. A
new standard for monitoring these Power attributes Attributes should be in line
with
already existing already-existing standards, such as [IEC.61850-7-4].

For some network management tasks tasks, it is desirable to receive
notifications from entities when their Power power value exceeds or falls
below given thresholds.

5.3.1. Real Power / Power Factor

The standard must provide means for reporting the real power for each
Power Interface as well as for an entity. Reporting Power power includes
reporting the direction of Power power flow.

5.3.2. Power Measurement Interval

The standard must provide means for reporting the corresponding time
or time interval for which a Power power value is reported. The Power power
value can be measured at the corresponding time or averaged over the
corresponding time interval.

5.3.3. Power Measurement Method

The standard must provide means to indicate the method how used to obtain
these
values have been obtained. values. Based on how the measurement was conducted, it is
possible to associate a certain degree of confidence with the
reported Power power value. For example, there are methods of measurement
such as direct Power power measurement, or by estimation based on performance
values, or hard coding hard-coding average Power power values for an entity.

5.3.4. Accuracy Of of Power And and Energy Values

The standard must provide means for reporting the accuracy of
reported Power power and Energy energy values.

5.3.5. Actual Voltage And and Current

The standard must provide means for reporting the actual voltage and
actual current for each Power Interface as well as for a device. In
case of For
AC Power power supply, means must be provided for reporting the actual
voltage and actual current per phase.

5.3.6. High/low Power High-Power/Low-Power Notifications

The standard must provide means for creating notifications if Power power
values of an entity rise above or fall below given thresholds.

5.3.7. Complex Power / Power Factor

The standard must provide means for reporting the complex power for
each Power Interface and for each phase at a Power Interface.
Besides In
addition to the real power, at least two out of the following three
quantities need to be reported: apparent power, reactive power, and
phase angle. The phase angle can be substituted by the power factor.

5.3.8. Actual AC Frequency

The standard must provide means for reporting the actual AC frequency
for each Power Interface.

5.3.9. Total Harmonic Distortion

The standard must provide means for reporting the Total Harmonic
Distortion (THD) of voltage and current for each Power Interface. In
case of
For AC Power power supply, means must be provided for reporting the THD per
phase.

5.3.10. Power Supply Impedance

The standard must provide means for reporting the impedance of Power a
power supply for each Power Interface. In case of For AC Power power supply, means
must be provided for reporting the impedance per phase.

5.4. Power State

Many entities have a limited number of discrete Power States.

There is a need to report the actual Power State of an entity, entity and to
provide the means for retrieving the list of all supported Power
States.

Different standards bodies have already defined sets of Power States
for some entities, and others are creating new Power State sets. In
this context, it is desirable that the standard support many of these
Power State standards. In order to support multiple management
systems that possibly using use different Power State sets, sets while
simultaneously interfacing with a particular entity, the Energy
Management standard System must provide means for supporting multiple Power
State sets used simultaneously at an entity.

Power States have parameters that describe its their properties. It is
required to have a standardized means for reporting some key
properties, such as the typical Power power of an entity in a certain
state.

There also is also a need to report statistics on Power States States, including
the time spent and as well as the received and provided Energy energy in a Power
State.

5.4.1. Actual Power State

The standard must provide means for reporting the actual Power State
of an entity.

5.4.2. List Of of Supported Power States

The standard must provide means for retrieving the list of all
potential Power States of an entity.

5.4.3. Multiple Power State Sets

The standard must provide means for supporting multiple Power State
sets simultaneously at an entity.

5.4.4. List Of of Supported Power State Sets

The standard must provide means for retrieving the list of all Power
State sets supported by an entity.

5.4.5. List Of of Supported Power States Within A within a Set

The standard must provide means for retrieving the list of all
potential Power States of an entity for each supported Power State
set.

5.4.6. Typical Power Per Power State

The standard must provide means for retrieving the typical Power power for
each supported Power State.

5.4.7. Power State Statistics

The standard must provide means for monitoring statistics per Power
State
State, including the total time spent in a Power State, the number of
times each state was entered entered, and the last time each state was
entered. More Power State statistics are addressed by requirement the
requirements in Section 5.5.3.

5.4.8. Power State Changes

The standard must provide means for generating a notification when
the actual Power State of an entity changes.

5.5. Energy

Monitoring

The monitoring of electrical Energy energy received or provided by an entity
is a core function of Energy Management. Since Energy energy is an
accumulated quantity, it is always reported for a certain interval of
time. This can be, for example, the time from the last restart of
the entity to the reporting time, the time from another past event to
the reporting time, the last given amount of time before the
reporting time, or a certain interval specified by two time stamps timestamps in
the past.

It is useful for entities to record their received and provided
Energy
energy per Power State and report these quantities.

5.5.1. Energy Measurement

The standard must provide means for reporting measured values of
Energy
energy and the direction of the Energy energy flow received or provided by
an entity. The standard must also provide the means to report the
Energy
energy passing through each Power Interface.

5.5.2. Time Intervals

The standard must provide means for reporting the time interval for
which an Energy energy value is reported.

5.5.3. Energy Per Power State

The standard must provide means for reporting the received and
provided Energy energy for each individual Power State. This extends the
requirement 5.4.7
requirements on Power State statistics. statistics described in Section 5.4.7.

5.6. Battery State

Batteries are special entities that supply Power. power. The status of
these batteries is typically controlled by automatic functions that
act locally on the entity entity, and manually by users of the entity.
There is a need to monitor the battery status of these entities by
network management systems.

Devices containing batteries can be modeled in two ways. The entire
device can be modeled as a single entity on which Energy-related energy-related
information is reported reported, or the battery can be modeled as an
individual entity for which Energy-related energy-related information is monitored
individually according to requirements in Sections 5.1 to through 5.5.

Further information on batteries is of interest for Energy
Management, such as the current charge of the battery, the number of
completed charging cycles, the charging state of the battery, its
temperature, and further additional static and dynamic battery properties.
It is desirable to receive notifications if the charge of a battery
becomes very low or if a battery needs to be replaced.

5.6.1. Battery Charge

The standard must provide means for reporting the current charge of a
battery, in units of milliampere hours milliampere-hours (mAh).

5.6.2. Battery Charging State

The standard must provide means for reporting the charging state
(charging, discharging, etc.) of a battery.

5.6.3. Battery Charging Cycles

The standard must provide means for reporting the number of completed
charging cycles of a battery.

5.6.4. Actual Battery Capacity

The standard must provide means for reporting the actual capacity of
a battery.

5.6.5. Actual Battery Capacity Temperature

The standard must provide means for reporting the actual temperature
of a battery.

5.6.6. Static Battery Properties

The standard must provide means for reporting static properties of a
battery, including the nominal capacity, the number of cells, the
nominal voltage, and the battery technology.

5.6.7. Low battery Battery Charge Notification

The standard must provide means for generating a notification when
the charge of a battery decreases below a given threshold. Note that
the threshold may depend on the battery technology.

5.6.8. Battery Replacement Notification

The standard must provide means for generating a notification when
the number of charging cycles of a battery exceeds a given threshold.

5.6.9. Multiple Batteries

If the battery technology allows, the standard must provide means for
meeting requirements in Sections 5.6.1 to through 5.6.8 for each
individual battery contained in a single entity.

5.7. Time Series Of of Measured Values

For some network management tasks, it is required to obtain obtaining time series of measured
values from entities, such as Power, Energy, power, energy, battery charge, etc. etc., is
required.

In general general, time series measurements could be obtained in many
different ways. Means should be provided to either push such values
from the location where they are available to the management system
or to have them stored locally for a sufficiently long period of time
such that a management system can retrieve the full time series.

The following issues are to be considered when designing time series
measurement and reporting functions:

1. Which quantities should be reported?

2. Which time interval type should be used (total, delta, sliding
window)?

3. Which measurement method should be used (sampled, continuous)?

4. Which reporting model should be used (push or pull)?

The most discussed and probably most needed quantity is Energy. energy. But
a need for others, such as Power power and battery charge charge, can be
identified as well.

There are three time interval types under discussion for accumulated
quantities such as Energy. energy. They can be reported as total values,
accumulated between the last restart of the measurement and a certain
timestamp. Alternatively, Energy energy can be reported as delta values
between two consecutive timestamps. Another alternative is reporting
values for sliding windows as specified in [IEC.61850-7-4].

For non-accumulative quantities, such as Power, power, different measurement
methods are considered. Such quantities can be reported using values
sampled at certain time stamps or alternatively timestamps or, alternatively, by mean values for
these quantities averaged between two (consecutive) time stamps timestamps or
over a sliding window.

Finally, time series can be reported using different reporting
models, particularly push-based or pull-based. Push-based reporting
can, for example, be realized by reporting Power power or Energy energy values
using the IPFIX IP Flow Information Export (IPFIX) protocol [RFC5101],[RFC5102]. SNMP [RFC5101]
[RFC5102]. The Simple Network Management Protocol (SNMP) [RFC3411]
is an example for of a protocol that can be used for realizing pull-based
reporting of time series.

For reporting time series of measured values values, the following
requirements have been identified. Further decisions concerning
issues discussed above need to be made when developing concrete
Energy Management standards.

5.7.1. Time Series Of of Energy Values

The standard must provide means for reporting time series of Energy energy
values. If the comparison of time series between multiple entities
is required, then time synchronization between those entities must be
provided (for example, with the Network Time Protocol [RFC5905]).

5.7.2. Time Series Interval Types

The standard must provide means for supporting alternative interval
types. Requirement The requirement in Section 5.5.2 applies to every reported
time value.

5.7.3. Time Series Storage Capacity

The standard should provide means for reporting the number of values
of a time series that can be stored for later reporting.

6. Control Of of Entities

Many entities control their Power State locally. Other entities need
interfaces for an Energy Management System to control their Power
State.

Power

A power supply is typically not self-managed by devices. And
controlling Power devices, and control
of a power supply is typically not conducted as an interaction
between an Energy Management System and the device itself. It is
rather an interaction between the management system and a device
providing
Power power at its Power Outlets. Similar to Power State
control, Power power supply control may be policy driven. Note that
shutting down the
Power power supply abruptly may have severe consequences
for the device.

6.1. Controlling Power States

The standard must provide means for setting Power States of entities.

6.2. Controlling Power Supply

The standard must provide means for switching Power a power supply off or
turning Power a power supply on at Power Interfaces providing Power power to one
or more device. devices.

7. Reporting On on Other Entities

As discussed in Section 5, not all Energy-related energy-related information may be
available at the concerned entity. entity in question. Such information may be
provided by other entities. This section covers only the reporting
of information
only. information. See Section 8 for requirements on controlling other
entities.

There are cases where a Power power supply unit switches Power power for several
entities by turning Power power on or off at a single Power Outlet or where
a Power power meter measures the accumulated Power power of several entities at a
single power line. Consequently, it should be possible to report
that a monitored value does not relate to just a single entity, entity but is
an accumulated value for a set of entities. All of these the entities
belonging to that set need to be identified.

7.1. Reports On on Other Entities

The standard must provide means for an entity to report information
on another entity.

7.2. Identity Of of Other Entities On on Which Information Is Reported

For entities that report on one or more other entities, the standard
must provide means for reporting the identity of other entities on
which information is reported. Note that, in some situations, a
manual configuration might be required to populate this information.

7.3. Reporting Quantities Accumulated Over over Multiple Entities

The standard must provide means for reporting the list of all
entities from which contributions are included in an accumulated
value.

7.4. List Of of All Entities On on Which Information Is Reported

For entities that report on one or more other entities, the standard
must provide means for reporting the complete list of all those
entities on which Energy-related energy-related information can be reported.

7.5. Content Of of Reports On on Other Entities

For entities that report on one or more other entities, the standard
must provide means for indicating which Energy-related what type or types of energy-
related information can be reported reported, and for which of those entities.

8. Controlling Other Entities

This section specifies requirements for controlling Power States and
power supply of entities by communicating with other entities that
have the means for doing that control.

8.1. Controlling Power States Of of Other Entities

Some entities have control over Power States of other entities. For
example
example, a gateway to a building system may have the means to control
the Power State of entities in the building that do not have an IP
interface. For this scenario and other similar cases means are
needed cases, a way to make
this control accessible to the Energy Management
System. System is needed.

In addition to this, addition, it is required that an entity that has its state
controlled by other entities has the means to report the list of
these other entities.

8.1.1. Control Of of Power States Of of Other Entities

The standard must provide means for an Energy Management System to
send Power State control commands to an entity that concern controls the
Power States of entities other than the one entity to which the command
was sent to. sent.

8.1.2. Identity Of of Other Power State Controlled Entities

The standard must provide means for reporting the identities of the
entities for which the reporting entity has the means to control
their Power States. Note that, in some situations, a manual
configuration might be required to populate this information.

8.1.3. List Of of All Power State Controlled Entities

The standard must provide means for an entity to report the list of
all entities for which it can control the Power State.

8.1.4. List Of of All Power State Controllers

The standard must provide means for an entity that receives commands
controlling its Power State from other entities to report the list of
all those entities.

8.2. Controlling Power Supply

Some entities may have control of the Power power supply of other entities,
for example, because the other entity is supplied via a Power Outlet
of the entity. For this and similar cases cases, means are needed to make
this control accessible to the Energy Management System. This need
is already addressed by the requirement in Section 6.2.

In addition, it is required that an entity that has its supply
controlled by other entities has the means to report the list of
these other entities. This need is already addressed by requirements
in Sections 5.2.3 and 5.2.4.

9. Security Considerations

Controlling Power State and Power power supply of entities are considered
highly sensitive actions actions, since they can significantly affect the
operation of directly and indirectly affected connected devices. Therefore Therefore,
all control actions addressed in sections Sections 6 and 8 must be
sufficiently protected through authentication, authorization, and
integrity protection mechanisms.

Entities that are not sufficiently secure to operate directly on the
public Internet do exist and can be a significant cause of risk, for
example, if the remote control functions described in sections Sections 6 and
8 can be exercised on those devices from anywhere on the Internet.
The standard needs to provide means for dealing with such cases. One
solution is providing means that allow for the isolation of such devices,
e.g.
e.g., behind a sufficiently secured gateway. Another solution is
allowing to
allow compliant implementations that have disabled to disable sensitive functions, or to
not
implemented sensitive functions.

Monitoring Energy-related implement such functions at all.

The monitoring of energy-related quantities of an entity as addressed
in Sections 5 - through 8 can be used to derive more information than
just the received and provided Energy, so energy; therefore, monitored data
requires protection. This protection includes authentication and
authorization of entities requesting access to monitored data as well
as confidentiality protection during transmission of monitored data.
Privacy of stored data in an entity must be taken into account.
Monitored data may be used as input to control, accounting, and other
actions, so integrity of transmitted information and authentication
of the origin may be needed.

9.1. Secure Energy Management

The standard must provide privacy, integrity, and authentication
mechanisms for all actions addressed in Sections 5 - through 8. The
security mechanisms must meet the security requirements elaborated detailed in
Section 1.4 of [RFC3411].

9.2. Isolation Of of Insufficiently Secure Entities

The standard must provide means to allow for the isolation of entities
that that are not sufficiently secure to operate on the public Internet,
e.g., behind a gateway that does implement implements sufficient security so that the
vulnerable entities are not directly exposed to the Internet.

9.3. Optional Restriction Of of Functions

The standard must allow for compliant implementations that do to disable
sensitive functions, or to not implement sensitive such functions or disable them at all, when
operating in environments that are not sufficiently secured environments. secured. This
applies particularly to the control functions described in sections Sections 6
and 8.

10. IANA Considerations

This document has no actions for IANA.

11. Acknowledgments

The authors would like to thank Ralf Wolter for his first essay on
this draft. document. Many thanks to William Mielke, John Parello,
JinHyeock Choi, Georgios Karagiannis, and Michael Suchoff for their
helpful comments on the draft. document. Many thanks for their IESG reviews to Stephen Farrell,
Robert Sparks, Adrian Farrel, Barry Leiba, Brian Haberman, Peter
Resnick, Sean Turner, Stewart Bryant, and Ralph Droms. Droms for their IESG
reviews. Finally, special thanks to the document shepherd shepherd, Nevil
Brownlee, and to the EMAN working group chairs: Nevil Brownlee and
Bruce Nordman.

12.

11. References

12.1.

11.1. Normative References

[RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An
Architecture for Describing Simple Network Management
Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
December 2002.

[RFC3621] Berger, A. and D. Romascanu, "Power Ethernet MIB", RFC
3621, December 2003.

[RFC4133] Bierman, A. and K. McCloghrie, "Entity MIB (Version 3)",
RFC 4133, August 2005.

[ANSI-TIA-1057]
Telecommunications Industry Association, , "ANSI-
TIA-1057-2006 - TIA ANSI-
TIA-1057-2006, "TIA Standard - -- Telecommunications - -- IP
Telephony Infrastructure - -- Link Layer Discovery Protocol
for Media Endpoint Devices ", Devices", April 2006.

[IEEE-100]
IEEE, , "Authoritative Dictionary of IEEE Standards Terms,
IEEE 100, Seventh Edition ", December 2000.

[IEC.61850-7-4]
International Electrotechnical Commission, "Communication
networks and systems for power utility automation -- Part
7-4: Basic communication structure -- Compatible logical
node classes and data object classes", March 2010.

[IEC.62053-21]
International Electrotechnical Commission, , "Electricity
metering equipment (a.c.) - -- Particular requirements - --
Part
22: 21: Static meters for active energy (classes 1 and 2) ",
2)", January 2003.

[IEC.62053-22]
International Electrotechnical Commission, , "Electricity
metering equipment (a.c.) - -- Particular requirements - --
Part 22: Static meters for active energy (classes 0,2 S
and 0,5
S) ", S)", January 2003.

[IEC.61850-7-4]
International Electrotechnical Commission, ,
"Communication networks and systems for power utility
automation - Part 7-4: Basic communication structure -
Compatible logical node classes and data object classes ",
2010.

[IEEE-100]
IEEE, "The Authoritative Dictionary of IEEE Standards
Terms, IEEE 100, Seventh Edition", December 2000.

[IEEE-1621]
Institute of Electrical and Electronics Engineers, , "IEEE
P1621-2004 -Draft
1621-2004 - IEEE Standard for User Interface Elements in
Power Control of Electronic Devices Employed in Office Office/
Consumer Environments ", June 2005. Environments", 2004.

[IEEE-802.1AB]
IEEE Computer Society, , "IEEE Std 802.1AB-2009 - -- IEEE
Standard for Local and metropolitan area networks - Metropolitan Area Networks --
Station and Media Access Control Discovery ", Discovery", September
2009.

12.2.

[RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An
Architecture for Describing Simple Network Management
Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
December 2002.

[RFC3621] Berger, A. and D. Romascanu, "Power Ethernet MIB", RFC
3621, December 2003.

[RFC6933] Bierman, A., Romascanu, D., Quittek, J., and M.
Chandramouli, "Entity MIB (Version 4)", RFC 6933, May
2013.

11.2. Informative References

[EMAN-STATEMENT]
Schoening, B., Chandramouli, M., and B. Nordman, "Energy
Management (EMAN) Applicability Statement", Work in
Progress, April 2013.

[IEC.60050]
International Electrotechnical Commission, "Electropedia:
The World's Online Electrotechnical Vocabulary", 2013,
<http://www.electropedia.org/iev/iev.nsf/
welcome?openform>.

[ITU-M.3400]
International Telecommunication Union, "ITU-T
Recommendation M.3400 -- Series M: TMN and Network
Maintenance: International Transmission Systems, Telephone
Circuits, Telegraphy, Facsimile and Leased Circuits --
Telecommunications Management Network - TMN management
functions", February 2000.

[RFC5101] Claise, B., "Specification of the IP Flow Information
Export (IPFIX) Protocol for the Exchange of IP Traffic
Flow Information", RFC 5101, January 2008.

[RFC5102] Quittek, J., Bryant, S., Claise, B., Aitken, P., and J.
Meyer, "Information Model for IP Flow Information Export",
RFC 5102, January 2008.

[RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network
Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, June 2010.

[I-D.ietf-eman-applicability-statement]
Schoening, B., Chandramouli, M., and B. Nordman, "Energy
Management (EMAN) Applicability Statement", draft-ietf-
eman-applicability-statement-03 (work in progress), April
2013.

[Fed-Std-1037C]
United States National Communications System Technology
and Standards Division, , "Federal Standard 1037C -
Telecommunications: Glossary of Telecommunication Terms ",
August 1996.

[IEC60050]
, "International Electrotechnical Vocabulary.
http://www.electropedia.org/iev/iev.nsf/welcome?openform
", .

[ITU-M.3400]
International Telecommunication Union, , "ITU-T
Recommendation M.3400 - Series M: TMN and Network
Maintenance: International Transmission Systems, Telephone
Circuits, Telegraphy, Facsimile and Leased Circuits -
Telecommunications Management Network - TMN management
functions ", February 2000.

Authors' Addresses

Juergen Quittek (editor)
NEC Europe Ltd.
NEC Laboratories Europe
Network Research Division
Kurfuersten-Anlage 36
Heidelberg 69115
Germany

Phone: +49 6221 4342-115
Email:
EMail: quittek@neclab.eu

Mouli Chandramouli
Cisco Systems, Inc.
Sarjapur Outer Ring Road
Bangalore
India

Phone: +91 80 4426 3947
Email:
EMail: moulchan@cisco.com

Rolf Winter
NEC Europe Ltd.
NEC Laboratories Europe
Network Research Division
Kurfuersten-Anlage 36
Heidelberg 69115
Germany

Phone: +49 6221 4342-121
Email:
EMail: Rolf.Winter@neclab.eu
Thomas Dietz
NEC Europe Ltd.
NEC Laboratories Europe
Network Research Division
Kurfuersten-Anlage 36
Heidelberg 69115
Germany

Phone: +49 6221 4342-128
Email:
EMail: Thomas.Dietz@neclab.eu

Benoit Claise
Cisco Systems, Inc.
De Kleetlaan 6a b1
Diegem 1831
Belgium

Phone: +32 2 704 5622
Email:
EMail: bclaise@cisco.com