Internet Engineering Task Force (IETF) J. Quittek

Internet Engineering Task Force (IETF) J. Quittek
Request for Comments: 7577 R. Winter
Category: Standards Track T. Dietz
ISSN: 2070-1721 NEC Europe, Ltd.
July 2015

Definition of Managed Objects for Battery Monitoring

Abstract

This memo defines a portion of the Management Information Base (MIB)
for use with network management protocols in the Internet community.
In particular, it defines managed objects that provide information on
the status of batteries in managed devices.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7577.

Copyright Notice

Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. The Internet-Standard Management Framework . . . . . . . . . 5
3. Design of the Battery MIB Module . . . . . . . . . . . . . . 6
3.1. MIB Module Structure . . . . . . . . . . . . . . . . . . 6
3.2. Battery Technologies . . . . . . . . . . . . . . . . . . 8
3.2.1. Guidelines for Adding Battery Technologies . . . . . 9
3.3. Battery Identification . . . . . . . . . . . . . . . . . 9
3.4. Charging Cycles . . . . . . . . . . . . . . . . . . . . . 10
3.5. Charge Control . . . . . . . . . . . . . . . . . . . . . 10
3.6. Imported Definitions . . . . . . . . . . . . . . . . . . 11
4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. Security Considerations . . . . . . . . . . . . . . . . . . . 33
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36
6.1. SMI Object Identifier Registration . . . . . . . . . . . 36
6.2. Battery Technology Registration . . . . . . . . . . . . . 36
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 37
7.1. Normative References . . . . . . . . . . . . . . . . . . 37
7.2. Informative References . . . . . . . . . . . . . . . . . 38
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 40
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40

1. Introduction

Today, more and more managed devices contain batteries that supply
them with power when disconnected from electrical power distribution
grids. Common examples are nomadic and mobile devices, such as
notebook computers, netbooks, and smartphones. The status of
batteries in such a device, particularly the charging status, is
typically controlled by automatic functions that act locally on the
device and manually by users of the device.

In addition to this, there is a need to monitor battery status of
these devices by network management systems. This document defines a
portion of the Management Information Base (MIB) that provides a
means for monitoring batteries in or attached to managed devices.
The Battery MIB module defined in Section 4 meets the requirements
for monitoring the status of batteries specified in RFC 6988
[RFC6988].

The Battery MIB module provides for monitoring the battery status.
According to the framework for energy management [RFC7326], it is an
Energy Managed Object; thus, MIB modules such as the Power and Energy
Monitoring MIB [RFC7460] could, in principle, be implemented for
batteries. The Battery MIB extends the more generic aspects of
energy management by adding battery-specific information. Amongst
other things, the Battery MIB enables the monitoring of:

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o the current charge of a battery,

o the age of a battery (charging cycles),

o the state of a battery (e.g., being recharged),

o last usage of a battery, and

o maximum energy provided by a battery (remaining and total
capacity).

Further, means are provided for battery-powered devices to send
notifications to inform the management system of needed replacement
when the current battery charge has dropped below a certain
threshold. The same applies to the age of a battery.

Many battery-driven devices have existing instrumentation for
monitoring the battery status because this is already needed for
local control of the battery by the device. This reduces the effort
for implementing the managed objects defined in this document. For
many devices, only additional software will be needed; no additional
hardware instrumentation for battery monitoring is necessary.

Since there are a lot of devices in use that contain more than one
battery, means for battery monitoring defined in this document
support addressing multiple batteries within a single device. Also,
batteries today often come in packages that can include
identification and might contain additional hardware and firmware.
The former allows tracing a battery and allows continuous monitoring
even if the battery is installed in another device. The firmware
version is useful information as the battery behavior might be
different for different firmware versions.

Not explicitly in the scope of definitions in this document are very
small backup batteries, for example, batteries used on a PC
motherboard to run the clock circuit and retain configuration memory
while the system is turned off. Other means may be required for
reporting on these batteries. However, the MIB module defined in
Section 3.1 can be used for this purpose.

A traditional type of managed device containing batteries is an
Uninterruptible Power Supply (UPS) system; these supply other devices
with electrical energy when the main power supply fails. There is
already a MIB module for managing UPS systems defined in RFC 1628
[RFC1628]. The UPS MIB module includes managed objects for
monitoring the batteries contained in a UPS system. However, the
information provided by the UPS MIB objects is limited and tailored
to the particular needs of UPS systems.

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A huge variety of battery technologies are available, and they are
evolving over time. For different applications, different battery
technologies are preferable, for example, because of different
weight, cost, robustness, charging time, etc. Some technologies,
such as lead-acid batteries, are continuously in use for decades,
while others, such as nickel-based battery technologies (nickel-
cadmium and nickel-metal hydride), have, to a wide extent, been
replaced by lithium-based battery technologies (lithium-ion and
lithium polymer).

The Battery MIB module uses a generic abstraction of batteries that
is independent of particular battery technologies and expected to be
applicable to future technologies as well. While identification of a
particular battery technology is supported by an extensible list of
battery technology identifiers (see Section 3.2), individual
properties of the technologies are not modeled by the abstraction.
In particular, methods for charging a battery, and the parameters of
those methods, which vary greatly between different technologies are
not individually modeled.

Instead, the Battery MIB module uses a simple common charging model
with batteries being in one of the following states: 'charging',
'maintaining charge', 'not charging', and 'discharging'. Control of
the charging process is limited to requests for transitions between
these states. For charging controllers that use charging state
engines with more states, implementations of the Battery MIB module
need to map those states to the four listed above.

For energy management systems that require finer-grained control of
the battery charging process, additional means need to be developed;
for example, MIB modules that model richer sets of charging states
and parameters for charging states.

All use cases sketched above assume that the batteries are contained
in a managed entity. In a typical case, this entity also hosts the
SNMP applications (command responder and notification generator) and
the charging controller for contained batteries. For definitions in
this document, it is not strictly required that batteries be
contained in the same managed entity, even though the Battery MIB
module (defined further below) uses the containment tree of the
Entity MIB module [RFC6933] for battery indexing.

External batteries can be supported as long as the charging
controller for these batteries is connected to the SNMP applications
that implement the Battery MIB module. An example with an external
battery is shown in the figure below. It illustrates that the
Battery MIB module is designed as an interface between the management
system and battery charging controller. Out of scope of this

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document is the interface between the battery charging controller and
controlled batteries.

+-----------------------------------+
| management system |
+-----------------+-----------------+
|
| Battery MIB
|
+-----------------+-----------------+
| managed element | |
| | |
| +--------------+--------------+ |
| | battery charging controller | |
| +-----+--------------+--------+ |
| | | |
| +-----+-----+ | |
| | internal | | |
| | battery | | |
| +-----------+ | |
+-----------------------+-----------+
|
+-----+-----+
| external |
| battery |
+-----------+

Figure 1: Battery MIB as Interface between Management System and
Battery-Charging Controller Supporting External Batteries

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC
2119 [RFC2119].

2. The Internet-Standard Management Framework

For a detailed overview of the documents that describe the current
Internet-Standard Management Framework, please refer to section 7 of
RFC 3410 [RFC3410].

Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. MIB objects are generally
accessed through the Simple Network Management Protocol (SNMP).
Objects in the MIB are defined using the mechanisms defined in the
Structure of Management Information (SMI). This memo specifies MIB
modules that are compliant to the SMIv2, which is described in STD

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58, RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58,RFC
2580 [RFC2580].

3. Design of the Battery MIB Module

3.1. MIB Module Structure

The Battery MIB module defined in this document defines objects for
reporting information about batteries. All managed objects providing
information on the status of a battery are contained in a single
table called "batteryTable". The batteryTable contains one
conceptual row per battery.

Batteries are indexed by the entPhysicalIndex of the
entPhysicalTable defined in the Entity MIB module [RFC6933]. An
implementation of the Entity MIB module complying with the
entity4CRCompliance MODULE-COMPLIANCE statement is required for
compliant implementations of the Battery MIB module.

If a battery is replaced, and the replacing battery uses the same
physical connector as the replaced battery, then the replacing
battery MUST be indexed with the same value of object
entPhysicalIndex as the replaced battery.

The kind of entity in the entPhysicalTable of the Entity MIB module
is indicated by the value of enumeration object entPhysicalClass.
All batteries SHOULD have the value of object entPhysicalClass set to
battery(14) in their row of the entPhysicalTable.

The batteryTable contains three groups of objects. The first group
(OIDs ending with 1-9) provides information on static properties of
the battery. The second group of objects (OIDs ending with 10-18)
provides information on the current battery state, if it is charging
or discharging, how much it is charged, its remaining capacity, the
number of experienced charging cycles, etc.

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batteryTable(1)
+--batteryEntry(1) [entPhysicalIndex]
+-- r-n SnmpAdminString batteryIdentifier(1)
+-- r-n SnmpAdminString batteryFirmwareVersion(2)
+-- r-n Enumeration batteryType(3)
+-- r-n Unsigned32 batteryTechnology(4)
+-- r-n Unsigned32 batteryDesignVoltage(5)
+-- r-n Unsigned32 batteryNumberOfCells(6)
+-- r-n Unsigned32 batteryDesignCapacity(7)
+-- r-n Unsigned32 batteryMaxChargingCurrent(8)
+-- r-n Unsigned32 batteryTrickleChargingCurrent(9)
+-- r-n Unsigned32 batteryActualCapacity(10)
+-- r-n Unsigned32 batteryChargingCycleCount(11)
+-- r-n DateAndTime batteryLastChargingCycleTime(12)
+-- r-n Enumeration batteryChargingOperState(13)
+-- rwn Enumeration batteryChargingAdminState(14)
+-- r-n Unsigned32 batteryActualCharge(15)
+-- r-n Unsigned32 batteryActualVoltage(16)
+-- r-n Integer32 batteryActualCurrent(17)
+-- r-n Integer32 batteryTemperature(18)
+-- rwn Unsigned32 batteryAlarmLowCharge(19)
+-- rwn Unsigned32 batteryAlarmLowVoltage(20)
+-- rwn Unsigned32 batteryAlarmLowCapacity(21)
+-- rwn Unsigned32 batteryAlarmHighCycleCount(22)
+-- rwn Integer32 batteryAlarmHighTemperature(23)
+-- rwn Integer32 batteryAlarmLowTemperature(24)
+-- r-n SnmpAdminString batteryCellIdentifier(25)

The third group of objects in this table (OIDs ending with 19-25) is
used for notifications. Threshold objects (OIDs ending with 19-24)
indicate thresholds that can be used to raise an alarm if a property
of the battery exceeds one of them. Raising an alarm may include
sending a notification.

The Battery MIB defines seven notifications for indicating:

1. a battery-charging state change that was not triggered by writing
to object batteryChargingAdminState,

2. a low-battery charging state,

3. a critical-battery state in which it cannot be used for power
supply,

4. an aged battery that may need to be replaced,

5. a battery that has exceeded a temperature threshold,

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6. a battery that has been connected, and

7. disconnection of one or more batteries.

Notifications 2-5 can use object batteryCellIdentifier to indicate a
specific cell or a set of cells within the battery that have
triggered the notification.

3.2. Battery Technologies

Static information in the batteryTable includes battery type and
technology. The battery type distinguishes primary (not
rechargeable) batteries from rechargeable (secondary) batteries and
capacitors. The battery technology describes the actual technology
of a battery, which typically is a chemical technology.

Since battery technologies are the subject of intensive research and
widely used technologies are often replaced by successor technologies
within a few years, the list of battery technologies was not chosen
as a fixed list. Instead, IANA has created a registry for battery
technologies at <http://www.iana.org/assignments/battery-
technologies> where numbers are assigned to battery technologies.

The table below shows battery technologies known today that are in
commercial use with the numbers assigned to them by IANA. New
entries can be added to the IANA registry if new technologies are
developed or if missing technologies are identified. Note that there
exists a huge number of battery types that are not listed in the IANA
registry. Many of them are experimental or cannot be used in an
economically useful way. New entries should be added to the IANA
registry only if the respective technologies are in commercial use
and relevant to standardized battery monitoring over the Internet.

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+--------------------------------+---------------+
| Battery Technology | Value |
+--------------------------------+---------------+
| Reserved | 0 |
| Unknown | 1 |
| Other | 2 |
| Zinc-carbon | 3 |
| Zinc chloride | 4 |
| Nickel oxyhydroxide | 5 |
| Lithium-copper oxide | 6 |
| Lithium-iron disulfide | 7 |
| Lithium-manganese dioxide | 8 |
| Zinc-air | 9 |
| Silver oxide | 10 |
| Alkaline | 11 |
| Lead-acid | 12 |
| Valve-Regulated Lead-Acid, Gel | 13 |
| Valve-Regulated Lead-Acid, AGM | 14 |
| Nickel-cadmium | 15 |
| Nickel-metal hydride | 16 |
| Nickel-zinc | 17 |
| Lithium-ion | 18 |
| Lithium polymer | 19 |
| Double layer capacitor | 20 |
| Unassigned | 21-4294967295 |
+--------------------------------+---------------+

3.2.1. Guidelines for Adding Battery Technologies

New entries can be added to the IANA registry if new technologies are
developed or if missing technologies are identified. Note that there
exists a huge number of battery types that are not listed in the IANA
registry. Many of them are experimental or cannot be used in an
economically useful way. New entries should be added to the IANA
registry only if the respective technologies are in commercial use
and relevant to standardized battery monitoring over the Internet.

3.3. Battery Identification

There are two identifiers to be used: the entPhysicalUUID defined in
the Entity MIB [RFC6933] module and the batteryIdentifier defined in
this module. A battery is linked to an entPhysicalUUID through the
shared entPhysicalIndex.

The batteryIdentifier uniquely identifies the battery itself while
the entPhysicalUUID identifies the slot of the device in which the
battery is (currently) contained. For a non-replaceable battery,
both identifiers are always linked to the same physical battery. But

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for batteries that can be replaced, the identifiers have different
functions.

The entPhysicalUUID is always the same for a certain battery slot of
a containing device even if the contained battery is replaced by
another. The batteryIdentifier is a representation of the battery
identifier set by the battery manufacturer. It is tied to the
battery and usually cannot be changed.

Many manufacturers deliver not just plain batteries but battery
packages including additional hardware and firmware. Typically,
these modules include a battery identifier that can by retrieved by a
device in which a battery has been installed. The value of the
object batteryIdentifier is an exact representation of this
identifier. The batteryIdentifier is useful when batteries are
removed and reinstalled in the same device or in other devices.
Then, the device or the network management system can trace batteries
and achieve continuity of battery monitoring.

3.4. Charging Cycles

The lifetime of a battery can be approximated using the measure of
charging cycles. A commonly used definition of a charging cycle is
the amount of discharge equal to the design (or nominal) capacity of
the battery [SBS]. This means that a single charging cycle may
include several steps of partial charging and discharging until the
amount of discharging has reached the design capacity of the battery.
After that, the next charging cycle immediately starts.

3.5. Charge Control

Managed object batteryChargingOperState indicates the current
operational charging state of a battery and is a read-only object.
For controlling the charging state, object batteryChargingAdminState
can be used. Writing to this object initiates a request to adapt the
operational state according to the value that has been written.

By default, the batteryChargingAdminState object is set to notSet(1).
In this state, the charging controller is using its predefined
policies to decide which operational state is suitable in the current
situation.

Setting the value of object batteryChargingAdminState may result in
not changing the state of the battery to this value or even in
setting the charging state to another value than the requested one.
Due to operational conditions and limitations of the implementation
of the Battery MIB module, changing the battery status according to a
set value of object batteryChargingAdminState might not be possible.

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For example, the charging controller might, at any time, decide to
enter state discharging(5), if there is an operational need to use
the battery for supplying power.

The object batteryChargingAdminState will not automatically change
when the object batteryChargingOperState changes. If the operational
state is changed, e.g., to the state discharging(5) due to
operational conditions, the admin state will remain in its current
state. The charging controller SHOULD change the operational state
to the state indicated by the object batteryChargingAdminState as
soon as operational conditions allow this change.

If a state change of the object batteryChargingAdminState is desired
upon change of the operational state, the object
batteryChargingOperState must be polled or the notification
batteryChargingStateNotification must be used to get notified about
the state change. This could be used, e.g., if maintaining charge is
not desired after fully charging a battery even if the charging
controller and battery support it. The object
batteryChargingAdminState can then be set to doNotCharge(3) when the
object batteryChargingOperState changes from charging(2) to
maintainingCharge(3). Another use case would be when performing
several charge and discharge cycles for battery maintenance.

3.6. Imported Definitions

The BATTERY-MIB module defined in this document imports definitions
from the following MIB modules: SNMPv2-SMI [RFC2578], SNMPv2-TC
[RFC2579], SNMPv2-CONF [RFC2580], SNMP-FRAMEWORK-MIB [RFC3411], and
ENTITY-MIB [RFC6933].

4. Definitions

BATTERY-MIB DEFINITIONS ::= BEGIN

IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, NOTIFICATION-TYPE,
mib-2, Integer32, Unsigned32
FROM SNMPv2-SMI -- RFC 2578
DateAndTime
FROM SNMPv2-TC -- RFC 2579
MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
FROM SNMPv2-CONF -- RFC 2580
SnmpAdminString
FROM SNMP-FRAMEWORK-MIB -- RFC 3411
entPhysicalIndex
FROM ENTITY-MIB; -- RFC 6933

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batteryMIB MODULE-IDENTITY
LAST-UPDATED "201506150000Z" -- 15 June 2015
ORGANIZATION "IETF EMAN Working Group"
CONTACT-INFO
"General Discussion: [email protected]
To Subscribe: <http://www.ietf.org/mailman/listinfo/eman>
Archive: <http://www.ietf.org/mail-archive/web/eman>

Editor:
Juergen Quittek
NEC Europe, Ltd.
NEC Laboratories Europe
Kurfuersten-Anlage 36
69115 Heidelberg
Germany
Tel: +49 6221 4342-115
Email: [email protected]"

DESCRIPTION
"This MIB module defines a set of objects for monitoring
batteries of networked devices and of their components.

Copyright (c) 2015 IETF Trust and the persons identified as
authors of the code. All rights reserved.

Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).

This version of this MIB module is part of RFC 7577; see
the RFC itself for full legal notices."
-- Revision history

REVISION "201506150000Z" -- 15 June 2015
DESCRIPTION
"Initial version published as RFC 7577."

::= { mib-2 233 }

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--******************************************************************
-- Top-Level Structure of the MIB Module
--******************************************************************

batteryNotifications OBJECT IDENTIFIER ::= { batteryMIB 0 }
batteryObjects OBJECT IDENTIFIER ::= { batteryMIB 1 }
batteryConformance OBJECT IDENTIFIER ::= { batteryMIB 2 }

--==================================================================
-- 1. Object Definitions
--==================================================================

--------------------------------------------------------------------
-- 1.1. Battery Table
--------------------------------------------------------------------
batteryTable OBJECT-TYPE
SYNTAX SEQUENCE OF BatteryEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"This table provides information on batteries. It contains
one conceptual row per battery in a managed entity.

Batteries are indexed by the entPhysicalIndex of the
entPhysicalTable defined in the ENTITY-MIB (RFC 6933).

For implementations of the BATTERY-MIB, an implementation of
the ENTITY-MIB complying with the entity4CRCompliance
MODULE-COMPLIANCE statement of the ENTITY-MIB is required.

If batteries are replaced, and the replacing battery uses
the same physical connector as the replaced battery, then
the replacing battery SHOULD be indexed with the same value
of object entPhysicalIndex as the replaced battery."
::= { batteryObjects 1 }

batteryEntry OBJECT-TYPE
SYNTAX BatteryEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry providing information on a battery."
INDEX { entPhysicalIndex }
::= { batteryTable 1 }

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BatteryEntry ::=
SEQUENCE {
batteryIdentifier SnmpAdminString,
batteryFirmwareVersion SnmpAdminString,
batteryType INTEGER,
batteryTechnology Unsigned32,
batteryDesignVoltage Unsigned32,
batteryNumberOfCells Unsigned32,
batteryDesignCapacity Unsigned32,
batteryMaxChargingCurrent Unsigned32,
batteryTrickleChargingCurrent Unsigned32,
batteryActualCapacity Unsigned32,
batteryChargingCycleCount Unsigned32,
batteryLastChargingCycleTime DateAndTime,
batteryChargingOperState INTEGER,
batteryChargingAdminState INTEGER,
batteryActualCharge Unsigned32,
batteryActualVoltage Unsigned32,
batteryActualCurrent Integer32,
batteryTemperature Integer32,
batteryAlarmLowCharge Unsigned32,
batteryAlarmLowVoltage Unsigned32,
batteryAlarmLowCapacity Unsigned32,
batteryAlarmHighCycleCount Unsigned32,
batteryAlarmHighTemperature Integer32,
batteryAlarmLowTemperature Integer32,
batteryCellIdentifier SnmpAdminString
}

batteryIdentifier OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object contains an identifier for the battery.

Many manufacturers deliver not only simple batteries but
battery packages including additional hardware and firmware.
Typically, these modules include an identifier that can be
retrieved by a device in which a battery has been installed.
The identifier is useful when batteries are removed and
reinstalled in the same or other devices. Then, the device
or the network management system can trace batteries and
achieve continuity of battery monitoring.

If the battery is identified by more than one value,
for example, by a model number and a serial number,
then the value of this object is a concatenation of these

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values, separated by the colon symbol ':'. The values
should be ordered so that a more significant value comes
before a less significant one. In the example above, the
(more significant) model number would be first, and the serial
number would follow: '<model number>:<serial number>'.

If the battery identifier cannot be represented using the
ISO/IEC IS 10646-1 character set, then a hexadecimal
encoding of a binary representation of the entire battery
identifier must be used.

The value of this object must be an empty string if there
is no battery identifier or if the battery identifier is
unknown."
::= { batteryEntry 1 }

batteryFirmwareVersion OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object indicates the version number of the firmware
that is included in a battery module.

Many manufacturers deliver not pure batteries but battery
packages including additional hardware and firmware.

Since the behavior of the battery may change with the
firmware, it may be useful to retrieve the firmware version
number.

The value of this object must be an empty string if there
is no firmware or if the version number of the firmware is
unknown."
::= { batteryEntry 2 }

batteryType OBJECT-TYPE
SYNTAX INTEGER {
unknown(1),
other(2),
primary(3),
rechargeable(4),
capacitor(5)
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object indicates the type of battery.

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It distinguishes between primary (not rechargeable)
batteries, rechargeable (secondary) batteries, and
capacitors. Capacitors are not really batteries but
are often used in the same way as a battery.

The value other(2) can be used if the battery type is known
but is none of the ones above. Value unknown(1) is to be used
if the type of battery cannot be determined."

::= { batteryEntry 3 }

batteryTechnology OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object indicates the technology used by the battery.
Numbers identifying battery technologies are registered at
IANA. A current list of assignments can be found at
<http://www.iana.org/assignments/battery-technologies>.

Value unknown(1) MUST be used if the technology of the
battery cannot be determined.

Value other(2) can be used if the battery technology is known
but is not one of the types already registered at IANA."
::= { batteryEntry 4 }

batteryDesignVoltage OBJECT-TYPE
SYNTAX Unsigned32
UNITS "millivolt"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object provides the design (or nominal) voltage of the
battery in units of millivolt (mV).

Note that the design voltage is a constant value and
typically different from the actual voltage of the battery.

A value of 0 indicates that the design voltage is unknown."
::= { batteryEntry 5 }

batteryNumberOfCells OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-only
STATUS current

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DESCRIPTION
"This object indicates the number of cells contained in the
battery.

A value of 0 indicates that the number of cells is unknown."
::= { batteryEntry 6 }

batteryDesignCapacity OBJECT-TYPE
SYNTAX Unsigned32
UNITS "milliampere hours"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object provides the design (or nominal) capacity of
the battery in units of milliampere hours (mAh).

Note that the design capacity is a constant value and
typically different from the actual capacity of the battery.
Usually, this is a value provided by the manufacturer of the
battery.

A value of 0 indicates that the design capacity is
unknown."
::= { batteryEntry 7 }

batteryMaxChargingCurrent OBJECT-TYPE
SYNTAX Unsigned32
UNITS "milliampere"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object provides the maximum current to be used for
charging the battery in units of milliampere (mA).

Note that the maximum charging current may not lead to
optimal charge of the battery and that some batteries can
only be charged with the maximum current for a limited
amount of time.

A value of 0 indicates that the maximum charging current is
unknown."
::= { batteryEntry 8 }

batteryTrickleChargingCurrent OBJECT-TYPE
SYNTAX Unsigned32
UNITS "milliampere"
MAX-ACCESS read-only
STATUS current

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DESCRIPTION
"This object provides the recommended average current
to be used for trickle charging the battery in units of
mA.

Typically, this is a value recommended by the manufacturer
of the battery or by the manufacturer of the charging
circuit.

A value of 0 indicates that the recommended trickle charging
current is unknown."
::= { batteryEntry 9 }

batteryActualCapacity OBJECT-TYPE
SYNTAX Unsigned32
UNITS "milliampere hours"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object provides the actual capacity of the
battery in units of mAh.

Typically, the actual capacity of a battery decreases
with time and with usage of the battery. It is usually
lower than the design capacity.

Note that the actual capacity needs to be measured and is
typically an estimate based on observed discharging and
charging cycles of the battery.

A value of 'ffffffff'H indicates that the actual capacity
cannot be determined."
::= { batteryEntry 10 }

batteryChargingCycleCount OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object indicates the number of completed charging
cycles that the battery underwent. In line with the
Smart Battery Data Specification Revision 1.1, a charging
cycle is defined as the process of discharging the battery
by a total amount equal to the battery design capacity as
given by object batteryDesignCapacity. A charging cycle
may include several steps of charging and discharging the
battery until the discharging amount given by
batteryDesignCapacity has been reached. As soon as a

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charging cycle has been completed, the next one starts
immediately, independent of the battery's current charge at
the end of the cycle.

For batteries of type primary(3), the value of this object is
always 0.

A value of 'ffffffff'H indicates that the number of charging
cycles cannot be determined."
::= { batteryEntry 11 }

batteryLastChargingCycleTime OBJECT-TYPE
SYNTAX DateAndTime
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The date and time of the last charging cycle. The value
'0000000000000000'H is returned if the battery has not been
charged yet or if the last charging time cannot be
determined.

For batteries of type primary(1), the value of this object is
always '0000000000000000'H."
::= { batteryEntry 12 }

batteryChargingOperState OBJECT-TYPE
SYNTAX INTEGER {
unknown(1),
charging(2),
maintainingCharge(3),
noCharging(4),
discharging(5)
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object indicates the current charging state of the
battery.

Value unknown(1) indicates that the charging state of the
battery cannot be determined.

Value charging(2) indicates that the battery is being
charged in a way such that the charge of the battery
increases.

Value maintainingCharge(3) indicates that the battery is
being charged with a low-average current that compensates

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self-discharging. This includes trickle charging, float
charging, and other methods for maintaining the current
charge of a battery. In typical implementations of charging
controllers, state maintainingCharge(3) is only applied
if the battery is fully charged or almost fully charged.

Value noCharging(4) indicates that the battery is not being
charged or discharged by electric current between the
battery and electric circuits external to the battery.
Note that the battery may still be subject to
self-discharging.

Value discharging(5) indicates that the battery is either
used as the power source for electric circuits external to
the battery or discharged intentionally by the
charging controller, e.g., for the purpose of battery
maintenance. In any case, the charge of the battery
decreases."
::= { batteryEntry 13 }

batteryChargingAdminState OBJECT-TYPE
SYNTAX INTEGER {
notSet(1),
charge(2),
doNotCharge(3),
discharge(4)
}
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The value of this object indicates the desired
charging state of the battery. The real state is
indicated by object batteryChargingOperState. See the
definition of object batteryChargingOperState for a
description of the values.

When this object is initialized by an implementation of the
BATTERY-MIB module, its value is set to notSet(1). In this
case, the charging controller is free to choose which
operational state is suitable.

When the batteryChargingAdminState object is set, then the
BATTERY-MIB implementation must try to set the battery
to the indicated state. The result will be indicated by
object batteryChargingOperState.

Setting object batteryChargingAdminState to value notSet(1)
is a request to the charging controller to operate

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autonomously and choose the operational state that is
suitable.

Setting object batteryChargingAdminState to value charge(2)
is a request to enter the operational state charging(2) until
the battery is fully charged. When the battery is fully
charged, or if the battery was already fully charged or
almost fully charged at the time of the request, the
operational state will change to maintainingCharge(3) if the
charging controller and the battery support the functionality
of maintaining the charge, or it will change to noCharging(4)
otherwise.

Setting object batteryChargingAdminState to value
doNotCharge(3) is a request for entering operational
state noCharging(4).

Setting object batteryChargingAdminState to value
discharge(4) is a request for entering operational
state discharging(5). Discharging can be accomplished
by ordinary use, applying a dedicated load, or any other
means. An example for applying this state is battery
maintenance. If the battery is empty or almost empty, the
operational state will change to noCharging(4).
The charging controller will decide which charge condition
will be considered empty dependent on the battery
technology used. This is done to avoid damage on the
battery due to deep discharge.

Due to operational conditions and limitations of the
implementation of the BATTERY-MIB module, changing the
battery status according to a set value of object
batteryChargingAdminState may not be possible.
Setting the value of object batteryChargingAdminState
may result in not changing the state of the battery
to this value or even in setting the charging state
to another value than the requested one. For example,
the charging controller might at any time decide to
enter state discharging(5), if there is an operational need
to use the battery for supplying power."
::= { batteryEntry 14 }

batteryActualCharge OBJECT-TYPE
SYNTAX Unsigned32
UNITS "milliampere hours"
MAX-ACCESS read-only
STATUS current

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DESCRIPTION
"This object provides the actual charge of the battery
in units of mAh.

Note that the actual charge needs to be measured and is
typically an estimate based on observed discharging and
charging cycles of the battery.

A value of 'ffffffff'H indicates that the actual charge
cannot be determined."
::= { batteryEntry 15 }

batteryActualVoltage OBJECT-TYPE
SYNTAX Unsigned32
UNITS "millivolt"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object provides the actual voltage of the battery
in units of mV.

A value of 'ffffffff'H indicates that the actual voltage
cannot be determined."
::= { batteryEntry 16 }

batteryActualCurrent OBJECT-TYPE
SYNTAX Integer32
UNITS "milliampere"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object provides the actual charging or discharging
current of the battery in units of mA.
The charging current is represented by positive values,
and the discharging current is represented by negative values.

A value of '7fffffff'H indicates that the actual current
cannot be determined."
::= { batteryEntry 17 }

batteryTemperature OBJECT-TYPE
SYNTAX Integer32
UNITS "deci-degrees Celsius"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The ambient temperature at or within close proximity
of the battery.

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A value of '7fffffff'H indicates that the temperature
cannot be determined."
::= { batteryEntry 18 }

batteryAlarmLowCharge OBJECT-TYPE
SYNTAX Unsigned32
UNITS "milliampere hours"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This object provides the lower-threshold value for object
batteryActualCharge. If the value of object
batteryActualCharge falls below this threshold,
a low-battery alarm will be raised. The alarm procedure may
include generating a batteryLowNotification.

This object should be set to a value such that when the
batteryLowNotification is generated, the battery is still
sufficiently charged to keep the device(s) that it powers
operational for a time long enough to take actions before
the powered device(s) enters a 'sleep' or 'off' state.

A value of 0 indicates that no alarm will be raised for any
value of object batteryActualVoltage."
::= { batteryEntry 19 }

batteryAlarmLowVoltage OBJECT-TYPE
SYNTAX Unsigned32
UNITS "millivolt"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This object provides the lower-threshold value for object
batteryActualVoltage. If the value of object
batteryActualVoltage falls below this threshold,
a low-battery alarm will be raised. The alarm procedure may
include generating a batteryLowNotification.

This object should be set to a value such that when the
batteryLowNotification is generated, the battery is still
sufficiently charged to keep the device(s) that it powers
operational for a time long enough to take actions before
the powered device(s) enters a 'sleep' or 'off' state.

A value of 0 indicates that no alarm will be raised for any
value of object batteryActualVoltage."
::= { batteryEntry 20 }

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batteryAlarmLowCapacity OBJECT-TYPE
SYNTAX Unsigned32
UNITS "milliampere hours"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This object provides the lower-threshold value for object
batteryActualCapacity. If the value of object
batteryActualCapacity falls below this threshold,
a battery aging alarm will be raised. The alarm procedure
may include generating a batteryAgingNotification.

A value of 0 indicates that no alarm will be raised for any
value of object batteryActualCapacity."
::= { batteryEntry 21 }

batteryAlarmHighCycleCount OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This object provides the upper-threshold value for object
batteryChargingCycleCount. If the value of object
batteryChargingCycleCount rises above this threshold,
a battery aging alarm will be raised. The alarm procedure
may include generating a batteryAgingNotification.

A value of 0 indicates that no alarm will be raised for any
value of object batteryChargingCycleCount."
::= { batteryEntry 22 }

batteryAlarmHighTemperature OBJECT-TYPE
SYNTAX Integer32
UNITS "deci-degrees Celsius"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This object provides the upper-threshold value for object
batteryTemperature. If the value of object
batteryTemperature rises above this threshold, a battery
high temperature alarm will be raised. The alarm procedure
may include generating a batteryTemperatureNotification.

A value of '7fffffff'H indicates that no alarm will be
raised for any value of object batteryTemperature."
::= { batteryEntry 23 }

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batteryAlarmLowTemperature OBJECT-TYPE
SYNTAX Integer32
UNITS "deci-degrees Celsius"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This object provides the lower-threshold value for object
batteryTemperature. If the value of object
batteryTemperature falls below this threshold, a battery
low temperature alarm will be raised. The alarm procedure
may include generating a batteryTemperatureNotification.

A value of '7fffffff'H indicates that no alarm will be
raised for any value of object batteryTemperature."
::= { batteryEntry 24 }

batteryCellIdentifier OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of this object identifies one or more cells of a
battery. The format of the cell identifier may vary between
different implementations. It should uniquely identify one
or more cells of the indexed battery.

This object can be used for batteries, such as lithium
polymer batteries for which battery controllers monitor
cells individually.

This object is used by notifications of types
batteryLowNotification, batteryTemperatureNotification,
batteryCriticalNotification, and batteryAgingNotification.
These notifications can use the value of this object to
indicate the event that triggered the generation of the
notification in more detail by specifying a single cell
or a set of cells within the battery that is specifically
addressed by the notification.

An example use case for this object is a single cell in a
battery that exceeds the temperature indicated by object
batteryAlarmHighTemperature. In such a case, a
batteryTemperatureNotification can be generated that not
only indicates the battery for which the temperature limit
has been exceeded but also the particular cell.

The initial value of this object is the empty string. The
value of this object is set each time a

Quittek, et al. Standards Track [Page 25]

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batteryLowNotification, batteryTemperatureNotification,
batteryCriticalNotification, or batteryAgingNotification
is generated.

When a notification is generated that does not indicate a
specific cell or set of cells, the value of this object is
set to the empty string."
::= { batteryEntry 25 }

--==================================================================
-- 2. Notifications
--==================================================================

batteryChargingStateNotification NOTIFICATION-TYPE
OBJECTS {
batteryChargingOperState
}
STATUS current
DESCRIPTION
"This notification can be generated when a charging state
of the battery (indicated by the value of object
batteryChargingOperState) is triggered by an event other
than a write action to object batteryChargingAdminState.
Such an event may, for example, be triggered by a local
battery controller."
::= { batteryNotifications 1 }

batteryLowNotification NOTIFICATION-TYPE
OBJECTS {
batteryActualCharge,
batteryActualVoltage,
batteryCellIdentifier
}
STATUS current
DESCRIPTION
"This notification can be generated when the current charge
(batteryActualCharge) or the current voltage
(batteryActualVoltage) of the battery falls below a
threshold defined by object batteryAlarmLowCharge or object
batteryAlarmLowVoltage, respectively.

Note that, typically, this notification is generated in a
state where the battery is still sufficiently charged to keep
the device(s) that it powers operational for some time.
If the charging state of the battery has become critical,
i.e., the device(s) powered by the battery must go to a
'sleep' or 'off' state, then the batteryCriticalNotification
should be used instead.

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If the low charge or voltage has been detected for a single
cell or a set of cells of the battery and not for the entire
battery, then object batteryCellIdentifier should be set to
a value that identifies the cell or set of cells.
Otherwise, the value of object batteryCellIdentifier should
be set to the empty string when this notification is
generated.

The notification should not be sent again for the same
battery or cell before either (a) the current voltage or
the current charge, respectively, has become higher than the
corresponding threshold through charging or (b) an indication
of a maintenance action has been detected, such as a battery
disconnection event or a reinitialization of the battery
monitoring system.

This notification should not be sent when the battery is in
a charging mode, i.e., the value of object
batteryChargingOperState is charging(2)."
::= { batteryNotifications 2 }

batteryCriticalNotification NOTIFICATION-TYPE
OBJECTS {
batteryActualCharge,
batteryActualVoltage,
batteryCellIdentifier
}
STATUS current
DESCRIPTION
"This notification can be generated when the current charge
of the battery falls so low that it cannot provide a
sufficient power supply function for regular operation
of the powered device(s). The battery needs to be charged
before it can be used for regular power supply again. The
battery may still provide sufficient power for a 'sleep'
mode of a powered device(s) or for a transition into an 'off'
mode.

If the critical state is caused by a single cell or a set of
cells of the battery, then object batteryCellIdentifier
should be set to a value that identifies the cell or set of
cells. Otherwise, the value of object batteryCellIdentifier
should be set to the empty string when this notification is
generated.

The notification should not be sent again for the same
battery before either the battery charge has increased
through charging to a non-critical value or an indication

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of a maintenance action has been detected, such as a battery
disconnection event or a reinitialization of the battery
monitoring system.

This notification should not be sent when the battery is in
a charging mode, i.e., the value of object
batteryChargingOperState is charging(2)."
::= { batteryNotifications 3 }

batteryTemperatureNotification NOTIFICATION-TYPE
OBJECTS {
batteryTemperature,
batteryCellIdentifier
}
STATUS current
DESCRIPTION
"This notification can be generated when the measured
temperature (batteryTemperature) rises above the threshold
defined by object batteryAlarmHighTemperature or falls
below the threshold defined by object
batteryAlarmLowTemperature.

If the low or high temperature has been detected for a
single cell or a set of cells of the battery and not for the
entire battery, then object batteryCellIdentifier should be
set to a value that identifies the cell or set of cells.
Otherwise, the value of object batteryCellIdentifier should
be set to the empty string when this notification is
generated.

It may occur that the temperature alternates between values
slightly below and slightly above a threshold. For limiting
the notification rate in such a case, this notification
should not be sent again for the same battery or cell,
respectively, within a time interval of 10 minutes.

An exception to the rate limitations occurs immediately
after the reinitialization of the battery monitoring system.
At this point in time, if the battery temperature is above
the threshold defined by object batteryAlarmHighTemperature
or below the threshold defined by object
batteryAlarmLowTemperature, respectively, then this
notification should be sent, independent of the time at
which previous notifications for the same battery or cell,
respectively, had been sent."
::= { batteryNotifications 4 }

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batteryAgingNotification NOTIFICATION-TYPE
OBJECTS {
batteryActualCapacity,
batteryChargingCycleCount,
batteryCellIdentifier
}
STATUS current
DESCRIPTION
"This notification can be generated when the actual
capacity (batteryActualCapacity) falls below a threshold
defined by object batteryAlarmLowCapacity
or when the charging cycle count of the battery
(batteryChargingCycleCount) exceeds the threshold defined
by object batteryAlarmHighCycleCount.

If the aging has been detected for a single cell or a set
of cells of the battery and not for the entire battery, then
object batteryCellIdentifier should be set to a value that
identifies the cell or set of cells. Otherwise, the value
of object batteryCellIdentifier should be set to the empty
string when this notification is generated.

This notification should not be sent again for the same
battery or cell, respectively, before an indication of a
maintenance action has been detected, such as a battery
disconnection event or a reinitialization of the battery
monitoring system."
::= { batteryNotifications 5 }

batteryConnectedNotification NOTIFICATION-TYPE
OBJECTS {
batteryIdentifier
}
STATUS current
DESCRIPTION
"This notification can be generated when it has been
detected that a battery has been connected. The battery
can be identified by the value of object batteryIdentifier
as well as by the value of index entPhysicalIndex that is
contained in the OID of object batteryIdentifier."
::= { batteryNotifications 6 }

batteryDisconnectedNotification NOTIFICATION-TYPE
STATUS current
DESCRIPTION
"This notification can be generated when it has been
detected that one or more batteries have been disconnected."
::= { batteryNotifications 7 }

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--==================================================================
-- 3. Conformance Information
--==================================================================

batteryCompliances OBJECT IDENTIFIER ::= { batteryConformance 1 }
batteryGroups OBJECT IDENTIFIER ::= { batteryConformance 2 }

--------------------------------------------------------------------
-- 3.1. Compliance Statements
--------------------------------------------------------------------

batteryCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for implementations of the
BATTERY-MIB module.

A compliant implementation MUST implement the objects
defined in the mandatory groups batteryDescriptionGroup
and batteryStatusGroup.

Note that this compliance statement requires
compliance with the entity4CRCompliance
MODULE-COMPLIANCE statement of the
ENTITY-MIB (RFC 6933)."
MODULE -- this module
MANDATORY-GROUPS {
batteryDescriptionGroup,
batteryStatusGroup
}

GROUP batteryAlarmThresholdsGroup
DESCRIPTION
"A compliant implementation does not have to implement
the batteryAlarmThresholdsGroup."

GROUP batteryNotificationsGroup
DESCRIPTION
"A compliant implementation does not have to implement
the batteryNotificationsGroup."

GROUP batteryPerCellNotificationsGroup
DESCRIPTION
"A compliant implementation does not have to implement
the batteryPerCellNotificationsGroup."

GROUP batteryAdminGroup
DESCRIPTION

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RFC 7577 Battery MIB July 2015

"A compliant implementation does not have to implement
the batteryAdminGroup."

OBJECT batteryAlarmLowCharge
MIN-ACCESS read-only
DESCRIPTION
"A compliant implementation is not required
to support set operations on this object."

OBJECT batteryAlarmLowVoltage
MIN-ACCESS read-only
DESCRIPTION
"A compliant implementation is not required
to support set operations on this object."

OBJECT batteryAlarmLowCapacity
MIN-ACCESS read-only
DESCRIPTION
"A compliant implementation is not required
to support set operations on this object."

OBJECT batteryAlarmHighCycleCount
MIN-ACCESS read-only
DESCRIPTION
"A compliant implementation is not required
to support set operations on this object."

OBJECT batteryAlarmHighTemperature
MIN-ACCESS read-only
DESCRIPTION
"A compliant implementation is not required
to support set operations on this object."

OBJECT batteryAlarmLowTemperature
MIN-ACCESS read-only
DESCRIPTION
"A compliant implementation is not required
to support set operations on this object."

::= { batteryCompliances 1 }

--------------------------------------------------------------------
-- 3.2. MIB Grouping
--------------------------------------------------------------------

batteryDescriptionGroup OBJECT-GROUP
OBJECTS {
batteryIdentifier,

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batteryFirmwareVersion,
batteryType,
batteryTechnology,
batteryDesignVoltage,
batteryNumberOfCells,
batteryDesignCapacity,
batteryMaxChargingCurrent,
batteryTrickleChargingCurrent
}
STATUS current
DESCRIPTION
"A compliant implementation MUST implement the objects
contained in this group."
::= { batteryGroups 1 }

batteryStatusGroup OBJECT-GROUP
OBJECTS {
batteryActualCapacity,
batteryChargingCycleCount,
batteryLastChargingCycleTime,
batteryChargingOperState,
batteryActualCharge,
batteryActualVoltage,
batteryActualCurrent,
batteryTemperature
}
STATUS current
DESCRIPTION
"A compliant implementation MUST implement the objects
contained in this group."
::= { batteryGroups 2 }

batteryAdminGroup OBJECT-GROUP
OBJECTS {
batteryChargingAdminState
}
STATUS current
DESCRIPTION
"A compliant implementation does not have to implement the
object contained in this group."
::= { batteryGroups 3 }

batteryAlarmThresholdsGroup OBJECT-GROUP
OBJECTS {
batteryAlarmLowCharge,
batteryAlarmLowVoltage,
batteryAlarmLowCapacity,
batteryAlarmHighCycleCount,

Quittek, et al. Standards Track [Page 32]

RFC 7577 Battery MIB July 2015

batteryAlarmHighTemperature,
batteryAlarmLowTemperature
}
STATUS current
DESCRIPTION
"A compliant implementation does not have to implement the
objects contained in this group."
::= { batteryGroups 4 }

batteryNotificationsGroup NOTIFICATION-GROUP
NOTIFICATIONS {
batteryChargingStateNotification,
batteryLowNotification,
batteryCriticalNotification,
batteryAgingNotification,
batteryTemperatureNotification,
batteryConnectedNotification,
batteryDisconnectedNotification
}
STATUS current
DESCRIPTION
"A compliant implementation does not have to implement the
notifications contained in this group."
::= { batteryGroups 5 }

batteryPerCellNotificationsGroup OBJECT-GROUP
OBJECTS {
batteryCellIdentifier
}
STATUS current
DESCRIPTION
"A compliant implementation does not have to implement the
object contained in this group."
::= { batteryGroups 6 }
END

5. Security Considerations

There are a number of management objects defined in this MIB module
with a MAX-ACCESS clause of read-write. Such objects may be
considered sensitive or vulnerable in some network environments. The
support for SET operations in a non-secure environment without proper
protection opens devices to attack. These are the tables and objects
and their sensitivity/vulnerability:

o batteryChargingAdminState:
Setting the battery charging state can be beneficial for an
operator for various reasons such as charging batteries when the

Quittek, et al. Standards Track [Page 33]

RFC 7577 Battery MIB July 2015

price of electricity is low. However, setting the charging state
can be used by an attacker to discharge batteries of devices and
thereby switching these devices off if they are powered solely by
batteries. In particular, if the batteryAlarmLowCharge and
batteryAlarmLowVoltage can also be set, this attack will go
unnoticed (i.e., no notifications are sent).

o batteryAlarmLowCharge and batteryAlarmLowVoltage:
These objects set the threshold for an alarm to be raised when the
battery charge or voltage falls below the corresponding one of
them. An attacker setting one of these alarm values can switch
off the alarm by setting it to the 'off' value 0, or it can modify
the alarm behavior by setting it to any other value. The result
may be loss of data if the battery runs empty without warning to a
recipient expecting such a notification.

o batteryAlarmLowCapacity and batteryAlarmHighCycleCount:
These objects set the threshold for an alarm to be raised when the
battery becomes older and less performant than required for stable
operation. An attacker setting this alarm value can switch off
the alarm by setting it to the 'off' value 0 or modify the alarm
behavior by setting it to any other value. This may lead to
either a costly replacement of a working battery or use of
batteries that are too old or too weak. The consequence of the
latter could be that, e.g., a battery cannot provide power long
enough between two scheduled charging actions causing the powered
device to shut down and potentially lose data.

o batteryAlarmHighTemperature and batteryAlarmLowTemperature:
These objects set thresholds for an alarm to be raised when the
battery rises above / falls below them. An attacker setting one
of these alarm values can switch off these alarms by setting them
to the 'off' value '7fffffff'H, or it can modify the alarm
behavior by setting them to any other value. The result may be,
e.g., an unnecessary shutdown of a device if
batteryAlarmHighTemperature is set too low, there is damage to the
device by temperatures that are too high if switched off or set to
values that are too high, or there is damage to the battery when,
e.g., it is being charged. Batteries can also be damaged, e.g.,
in an attempt to charge them at temperatures that are too low.

Some of the readable objects in this MIB module (i.e., objects with a
MAX-ACCESS other than not-accessible) may be considered sensitive or
vulnerable in some network environments. It is thus important to
control even GET and/or NOTIFY access to these objects and possibly
to even encrypt the values of these objects when sending them over
the network via SNMP. These are the tables and objects and their
sensitivity/vulnerability:

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All potentially sensible or vulnerable objects of this MIB module are
in the batteryTable. In general, there are no serious operational
vulnerabilities foreseen in case of an unauthorized read access to
this table. However, corporate confidentiality issues need to be
considered. The following information or parts of it might be a
trade secret:

o the number of batteries installed in a managed node (batteryIndex)

o properties of these batteries (batteryActualCapacity and
batteryChargingCycleCount)

o the time at which the next replacement cycle for batteries can be
expected (batteryAlarmLowCapacity and batteryAlarmHighCycleCount)

o the types of batteries in use and their firmware versions
(batteryIdentifier, batteryFirmwareVersion, batteryType, and
batteryTechnology)

For any battery-powered device whose use can be correlated to an
individual or a small group of individuals, the following objects
have the potential to reveal information about those individuals'
activities or habits (e.g., if they are near a power outlet, if they
have been using their devices heavily, etc.):

o batteryChargingCycleCount

o batteryLastChargingCycleTime

o batteryChargingOperState

o batteryActualCharge

o batteryActualVoltage

o batteryActualCurrent

o batteryTemperature

o batteryAlarmLowCharge

o batteryAlarmLowVoltage

o batteryAlarmLowCapacity

o batteryAlarmHighCycleCount

o batteryAlarmHighTemperature

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RFC 7577 Battery MIB July 2015

o batteryAlarmLowTemperature

Implementers of this specification should use appropriate privacy
protections as discussed in Section 9 of "Requirements for Energy
Management" [RFC6988]. Battery monitoring of devices used by
individuals or in homes should only occur with proper authorization.

SNMP versions prior to SNMPv3 did not include adequate security.
Even if the network itself is secure (for example by using IPsec),
there is no control as to who on the secure network is allowed to
access and GET/SET (read/change/create/delete) the objects in this
MIB module.

Implementations SHOULD provide the security features described by the
SNMPv3 framework (see [RFC3410]), and implementations claiming
compliance to the SNMPv3 standard MUST include full support for
authentication and privacy via the User-based Security Model (USM)
[RFC3414] with the AES cipher algorithm [RFC3826]. Implementations
MAY also provide support for the Transport Security Model (TSM)
[RFC5591] in combination with a secure transport such as SSH
[RFC5592] or TLS/DTLS [RFC6353].

Further, deployment of SNMP versions prior to SNMPv3 is NOT
RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to
enable cryptographic security. It is then a customer/operator
responsibility to ensure that the SNMP entity giving access to an
instance of this MIB module is properly configured to give access to
the objects only to those principals (users) that have legitimate
rights to indeed GET or SET (change/create/delete) them.

6. IANA Considerations

6.1. SMI Object Identifier Registration

The Battery MIB module defined in this document uses the following
IANA-assigned OBJECT IDENTIFIER value recorded in the SMI Numbers
registry:

Descriptor OBJECT IDENTIFIER value
---------- -----------------------
batteryMIB { mib-2 233 }

6.2. Battery Technology Registration

Object batteryTechnology defined in Section 4 reports battery
technologies. Eighteen values for battery technologies have
initially been defined. They are listed in a table in Section 3.2.

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For ensuring extensibility of this list, IANA has created a registry
for battery technologies at <http://www.iana.org/assignments/battery-
technologies> and filled it with the initial list given in
Section 3.2.

New assignments of numbers for battery technologies will be
administered by IANA through Expert Review [RFC5226]. Experts must
check for sufficient relevance of a battery technology to be added
according to the guidelines in Section 3.2.1.

7. References

7.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.

[RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Structure of Management Information
Version 2 (SMIv2)", STD 58, RFC 2578,
DOI 10.17487/RFC2578, April 1999,
<http://www.rfc-editor.org/info/rfc2578>.

[RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Textual Conventions for SMIv2",
STD 58, RFC 2579, DOI 10.17487/RFC2579, April 1999,
<http://www.rfc-editor.org/info/rfc2579>.

[RFC2580] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Conformance Statements for SMIv2",
STD 58, RFC 2580, DOI 10.17487/RFC2580, April 1999,
<http://www.rfc-editor.org/info/rfc2580>.

[RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An
Architecture for Describing Simple Network Management
Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
DOI 10.17487/RFC3411, December 2002,
<http://www.rfc-editor.org/info/rfc3411>.

[RFC3414] Blumenthal, U. and B. Wijnen, "User-based Security Model
(USM) for version 3 of the Simple Network Management
Protocol (SNMPv3)", STD 62, RFC 3414,
DOI 10.17487/RFC3414, December 2002,
<http://www.rfc-editor.org/info/rfc3414>.

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RFC 7577 Battery MIB July 2015

[RFC3826] Blumenthal, U., Maino, F., and K. McCloghrie, "The
Advanced Encryption Standard (AES) Cipher Algorithm in the
SNMP User-based Security Model", RFC 3826,
DOI 10.17487/RFC3826, June 2004,
<http://www.rfc-editor.org/info/rfc3826>.

[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.

[RFC5591] Harrington, D. and W. Hardaker, "Transport Security Model
for the Simple Network Management Protocol (SNMP)",
STD 78, RFC 5591, DOI 10.17487/RFC5591, June 2009,
<http://www.rfc-editor.org/info/rfc5591>.

[RFC5592] Harrington, D., Salowey, J., and W. Hardaker, "Secure
Shell Transport Model for the Simple Network Management
Protocol (SNMP)", RFC 5592, DOI 10.17487/RFC5592, June
2009, <http://www.rfc-editor.org/info/rfc5592>.

[RFC6353] Hardaker, W., "Transport Layer Security (TLS) Transport
Model for the Simple Network Management Protocol (SNMP)",
STD 78, RFC 6353, DOI 10.17487/RFC6353, July 2011,
<http://www.rfc-editor.org/info/rfc6353>.

[RFC6933] Bierman, A., Romascanu, D., Quittek, J., and M.
Chandramouli, "Entity MIB (Version 4)", RFC 6933,
DOI 10.17487/RFC6933, May 2013,
<http://www.rfc-editor.org/info/rfc6933>.

7.2. Informative References

[RFC1628] Case, J., Ed., "UPS Management Information Base",
RFC 1628, DOI 10.17487/RFC1628, May 1994,
<http://www.rfc-editor.org/info/rfc1628>.

[RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410,
DOI 10.17487/RFC3410, December 2002,
<http://www.rfc-editor.org/info/rfc3410>.

[RFC6988] Quittek, J., Ed., Chandramouli, M., Winter, R., Dietz, T.,
and B. Claise, "Requirements for Energy Management",
RFC 6988, DOI 10.17487/RFC6988, September 2013,
<http://www.rfc-editor.org/info/rfc6988>.

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[RFC7326] Parello, J., Claise, B., Schoening, B., and J. Quittek,
"Energy Management Framework", RFC 7326,
DOI 10.17487/RFC7326, September 2014,
<http://www.rfc-editor.org/info/rfc7326>.

[RFC7460] Chandramouli, M., Claise, B., Schoening, B., Quittek, J.,
and T. Dietz, "Monitoring and Control MIB for Power and
Energy", RFC 7460, DOI 10.17487/RFC7460, March 2015,
<http://www.rfc-editor.org/info/rfc7460>.

[SBS] "Smart Battery Data Specification", Revision 1.1, December
1998.

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RFC 7577 Battery MIB July 2015

Acknowledgements

We would like to thank Steven Chew, Bill Mielke, and Alan Luchuk for
their valuable input.

Authors' Addresses

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

Phone: +49 6221 4342-115
Email: [email protected]

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

Phone: +49 6221 4342-121
Email: [email protected]

Thomas Dietz
NEC Europe, Ltd.
NEC Laboratories Europe
Network Research Division
Kurfuersten-Anlage 36
Heidelberg 69115
Germany

Phone: +49 6221 4342-128
Email: [email protected]

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