it is not an alarm state transition. The alarmModelTable provides a
means of defining the raise/clear and other state transition
relationships between alarm states. The alarmModelIndex acts as a
unique identifier for an alarm. An alarm model consists of
definitions of the possible states an alarm can assume as well as the
Object Identifier (OID) of the Notification associated with this
alarm state. The object alarmModelState defines the states of an
alarm.
The alarmActiveTable contains a list of alarms that are currently
occurring on a system. It is intended that this table be queried
upon device discovery and rediscovery to determine which alarms are
currently active on the device.
The alarmActiveVariableTable contains the Notification variable
bindings associated with the alarms in the alarmActiveTable.
The alarmActiveStatsTable contains current and total raised alarm
counts as well as the time of the last alarm raise and alarm clears
per named alarm list.
The alarmClearTable contains recently cleared alarms. It contains up
to alarmClearMaximum cleared alarms.
The MIB also defines generic alarm Notifications that can be used
when there is not an existing applicable Notification to signal the
alarm state transition - alarmActiveState and alarmClearState.
4.1.1. Extensibility
The relationship between the Alarm MIB and the other alarm model MIB
modules is expressed by the following: The alarmModelTable has a
corresponding table in the specific MIB. For each row in the
specific MIB alarm model table there is one row in the
alarmModelTable. The alarmActiveTable has a corresponding table in
the specific MIBs. For each row in the specific MIB active alarm
table, there is one row in the alarmActiveTable. The
alarmModelSpecificPointer object in the alarmModelTable points to the
specific model entry in an extended alarm model table corresponding
to this particular alarm. The alarmActiveSpecificPointer object in
the alarmActiveTable points to the specific active alarm entry in an
extended active alarm table corresponding to this particular alarm
instance.
Additional extensions can be defined by defining an AUGMENTATION of
either the Alarm or ITU Alarm tables. As the alarm model table only
provides a mechanism to point at one specific alarm model, additional
specific models SHOULD define another mechanism to map from the
generic alarm model to the additional model.
4.1.2. Problem Indication
The problem that each alarm indicates is identified through the
Object Identifier of the NotificationId of the state transition, and,
optionally, the ITU parameters. alarmModelDescription provides a
description of the alarm state suitable for displaying to an
operator.
4.1.3. Alarm State Transition Notification
The SNMP-TARGET-MIB [RFC3413] provides the ability to specify which
managers, if any, receive Notifications of problems. Solutions can
therefore use the features of this MIB to change the Notification
behaviour of their implementations. Specifying target hosts in this
MIB along with specifying notifications in the
alarmModelNotificationId would allow Notifications to be logged and
sent out to management stations in an architecture as described in
section 3.2. Specifying no target hosts in this MIB along with
specifying notifications in the alarmModelNotificationId would allow
Notifications to be logged but not sent out to management stations in
an architecture as described in section 3.2. Regardless of what is
defined in the SNMP-TARGET-MIB, specifying { 0 0 } in the
alarmModelNotificationId would result in no notifications being
logged or sent to management stations as a consequence of this
particular alarm state transition.
Alarms are modelled by defining all possible states in the
alarmModelTable, as well as defining alarmModelNotificationId,
alarmModelVarbindIndex, and alarmModelVarbindValue for each of the
possible alarm states. Optionally, ituAlarmPerceivedSeverity models
the states in terms of ITU perceived severity.
4.1.4. Active Alarm Resource Identifier
Resources under alarm can be identified using the
alarmActiveResourceId. This OBJECT IDENTIFIER points to an
appropriate object to identify the given resource, depending on the
type of the resource.
The consumer of the alarmActiveResourceId does not necessarily need
to know the type of the resource in the resource ID, but if they want
to know this, examining the content of the resource ID can derive it
- 1.3.6.1.2.1.2.2.1.1.something is an interface, for example. It is
therefore good practice to use resource IDs that can be consistently
used across technologies, such as ifIndex, entPhysicalIndex or
sysApplRunIndex, to minimize the number of resource prefixes a
manager interested in a resource type needs to learn.
Resource ID can be calculated using the alarmModelResourcePrefix,
alarmModelVarbindSubtree and the Notification varbinds. This allows
for both the managed element to be able to compute and populate the
alarmActiveResourceId object and for the manager to be able to
determine when two separate alarm instances are referring to the same
resource.
If alarmModelResourcePrefix has a value of 0.0, then
alarmActiveResourceId is simply the variable identifier of the first
Notification varbind that matches the prefix defined in
alarmModelVarbindSubtree. Otherwise, alarmActiveResourceId is
calculated by appending the instance information from the first
Notification varbind that matches alarmModelVarbindSubtree to the
prefix defined in alarmModelResourcePrefix. The instance information
is the portion of the variable identifier following the part that
matched alarmModelVarbindSubtree. If no match is found, then
alarmActiveResourceId is simply the value of
alarmModelResourcePrefix.
In addition to this, the variable bindings from the Notifications
that signal the alarm state transitions are stored in the active
alarm variable table. This allows for implementations familiar with
the particular Notifications to implement other forms of resource
identification.
For Example:
A) Consider an alarm modelled using the authenticationFailure
[RFC3418] Notification.
authenticationFailure NOTIFICATION-TYPE
STATUS current
DESCRIPTION
"An authenticationFailure trap signifies that the SNMPv2
entity, acting in an agent role, has received a protocol
message that is not properly authenticated. While all
implementations of the SNMPv2 must be capable of generating
this trap, the snmpEnableAuthenTraps object indicates
whether this trap will be generated."
::= { snmpTraps 5 }
To set the resource ID to be usmStats, 1.3.6.1.6.3.15.1.1,
configure as follows:
alarmModelVarbindSubtree = 0.0
alarmModelResourcePrefix = usmStats (1.3.6.1.6.3.15.1.1)
B) Consider an alarm modelled using linkDown [RFC2863]
linkDown NOTIFICATION-TYPE
OBJECTS { ifIndex, ifAdminStatus, ifOperStatus }
STATUS current
DESCRIPTION
""
::= { snmpTraps 3 }
To set the resource Id to be the ifIndex, configure as follows:
alarmModelVarbindSubtree = ifIndex (1.3.6.1.2.1.2.2.1.1)
alarmModelResourcePrefix = 0.0
Alternatively, since ifIndex is the first varbind, the following
would also work, but might be less meaningful to a human reader
of the MIB table:
alarmModelVarbindSubtree = 0.0
alarmModelResourcePrefix = 0.0
C) Consider an alarm modelled using the bgpBackwardTransition
[RFC1657] Notification.
bgpBackwardTransition NOTIFICATION-TYPE
OBJECTS { bgpPeerLastError,
bgpPeerState }
STATUS current
DESCRIPTION
"The BGPBackwardTransition Event is generated
when the BGP FSM moves from a higher numbered
state to a lower numbered state."
::= { bgpTraps 2 }
To set the resource Id to be the bgpPeerRemoteAddr, the index to
the bgpTable, where bgpPeerState resides, configure as follows:
alarmModelVarbindSubtree = bgpPeerState
(1.3.6.1.2.1.15.3.1.2)
alarmModelResourcePrefix = bgpPeerRemoteAddr
(1.3.6.1.2.1.15.3.1.7)
4.1.5. Configurable Alarm Models
The alarm model table SHOULD be initially populated by the system.
The objects in alarmModelTable and ituAlarmTable have a MAX-ACCESS of
read-create, which allows managers to modify the alarm models to suit
their requirements.
4.1.6. Active Alarm Management
Lists of alarms currently active on an SNMP entity are stored in the
alarmActiveTable and, optionally, a model specific alarmTable, e.g.,
the ituAlarmActiveTable.
4.1.7. Distributed Alarm Management
Distributed alarm management can be achieved by support of the Alarm
MIB on both the alarm detection point and on the mid-level manager.
This is facilitated by the ability to be able to store different
named alarm lists. A mid-level manager could create an alarmListName
for each of the devices it manages and therefore store separate lists
for each device. In addition, the context and IP addresses of the
alarm detection point are stored in the alarmActiveTable.
4.2. Definitions
ALARM-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, NOTIFICATION-TYPE,
Integer32, Unsigned32, Gauge32,
TimeTicks, Counter32, Counter64,
IpAddress, Opaque, mib-2,
zeroDotZero
FROM SNMPv2-SMI -- [RFC2578]
DateAndTime,
RowStatus, RowPointer,
TEXTUAL-CONVENTION
FROM SNMPv2-TC -- [RFC2579]
SnmpAdminString
FROM SNMP-FRAMEWORK-MIB -- [RFC3411]
InetAddressType, InetAddress
FROM INET-ADDRESS-MIB -- [RFC3291]
MODULE-COMPLIANCE, OBJECT-GROUP,
NOTIFICATION-GROUP
FROM SNMPv2-CONF -- [RFC2580]
ZeroBasedCounter32
FROM RMON2-MIB; -- [RFC2021]
alarmMIB MODULE-IDENTITY
LAST-UPDATED "200409090000Z" -- September 09, 2004
ORGANIZATION "IETF Distributed Management Working Group"
CONTACT-INFO
"WG EMail: disman@ietf.org
Subscribe: disman-request@ietf.org
http://www.ietf.org/html.charters/disman-charter.html
Chair: Randy Presuhn
randy_presuhn@mindspring.com
Editors: Sharon Chisholm
Nortel Networks
PO Box 3511 Station C
Ottawa, Ont. K1Y 4H7
Canada
schishol@nortelnetworks.com
Dan Romascanu
Avaya
Atidim Technology Park, Bldg. #3
Tel Aviv, 61131
Israel
Tel: +972-3-645-8414
Email: dromasca@avaya.com"
DESCRIPTION
"The MIB module describes a generic solution
to model alarms and to store the current list
of active alarms.
Copyright (C) The Internet Society (2004). The
initial version of this MIB module was published
in RFC 3877. For full legal notices see the RFC
itself. Supplementary information may be available on:
http://www.ietf.org/copyrights/ianamib.html"
REVISION "200409090000Z" -- September 09, 2004
DESCRIPTION
"Initial version, published as RFC 3877."
::= { mib-2 118 }
alarmObjects OBJECT IDENTIFIER ::= { alarmMIB 1 }
alarmNotifications OBJECT IDENTIFIER ::= { alarmMIB 0 }
alarmModel OBJECT IDENTIFIER ::= { alarmObjects 1 }
alarmActive OBJECT IDENTIFIER ::= { alarmObjects 2 }
alarmClear OBJECT IDENTIFIER ::= { alarmObjects 3 }
-- Textual Conventions
-- ResourceId is intended to be a general textual convention
-- that can be used outside of the set of MIBs related to
-- Alarm Management.
ResourceId ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A unique identifier for this resource.
The type of the resource can be determined by looking
at the OID that describes the resource.
Resources must be identified in a consistent manner.
For example, if this resource is an interface, this
object MUST point to an ifIndex and if this resource
is a physical entity [RFC2737], then this MUST point
to an entPhysicalDescr, given that entPhysicalIndex
is not accessible. In general, the value is the
name of the instance of the first accessible columnar
object in the conceptual row of a table that is
meaningful for this resource type, which SHOULD
be defined in an IETF standard MIB."
SYNTAX OBJECT IDENTIFIER
-- LocalSnmpEngineOrZeroLenStr is intended to be a general
-- textual convention that can be used outside of the set of
-- MIBs related to Alarm Management.
LocalSnmpEngineOrZeroLenStr ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An SNMP Engine ID or a zero-length string. The
instantiation of this textual convention will provide
guidance on when this will be an SNMP Engine ID and
when it will be a zero lengths string"
SYNTAX OCTET STRING (SIZE(0 | 5..32))
-- Alarm Model
alarmModelLastChanged OBJECT-TYPE
SYNTAX TimeTicks
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of sysUpTime at the time of the last
creation, deletion or modification of an entry in
the alarmModelTable.
If the number and content of entries has been unchanged
since the last re-initialization of the local network
management subsystem, then the value of this object
MUST be zero."
::= { alarmModel 1 }
alarmModelTable OBJECT-TYPE
SYNTAX SEQUENCE OF AlarmModelEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table of information about possible alarms on the system,
and how they have been modelled."
::= { alarmModel 2 }
alarmModelEntry OBJECT-TYPE
SYNTAX AlarmModelEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"Entries appear in this table for each possible alarm state.
This table MUST be persistent across system reboots."
INDEX { alarmListName, alarmModelIndex, alarmModelState }
::= { alarmModelTable 1 }
AlarmModelEntry ::= SEQUENCE {
alarmModelIndex Unsigned32,
alarmModelState Unsigned32,
alarmModelNotificationId OBJECT IDENTIFIER,
alarmModelVarbindIndex Unsigned32,
alarmModelVarbindValue Integer32,
alarmModelDescription SnmpAdminString,
alarmModelSpecificPointer RowPointer,
alarmModelVarbindSubtree OBJECT IDENTIFIER,
alarmModelResourcePrefix OBJECT IDENTIFIER,
alarmModelRowStatus RowStatus
}
alarmModelIndex OBJECT-TYPE
SYNTAX Unsigned32 (1..4294967295)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An integer that acts as an alarm Id
to uniquely identify each alarm
within the named alarm list. "
::= { alarmModelEntry 1 }
alarmModelState OBJECT-TYPE
SYNTAX Unsigned32 (1..4294967295)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A value of 1 MUST indicate a clear alarm state.
The value of this object MUST be less than the
alarmModelState of more severe alarm states for
this alarm. The value of this object MUST be more
than the alarmModelState of less severe alarm states
for this alarm."
::= { alarmModelEntry 2 }
alarmModelNotificationId OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The NOTIFICATION-TYPE object identifier of this alarm
state transition. If there is no notification associated
with this alarm state, the value of this object MUST be
’0.0’"
DEFVAL { zeroDotZero }
::= { alarmModelEntry 3 }
alarmModelVarbindIndex OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The index into the varbind listing of the notification
indicated by alarmModelNotificationId which helps
signal that the given alarm has changed state.
If there is no applicable varbind, the value of this
object MUST be zero.
Note that the value of alarmModelVarbindIndex acknowledges
the existence of the first two obligatory varbinds in
the InformRequest-PDU and SNMPv2-Trap-PDU (sysUpTime.0
and snmpTrapOID.0). That is, a value of 2 refers to
the snmpTrapOID.0.
If the incoming notification is instead an SNMPv1 Trap-PDU,
then an appropriate value for sysUpTime.0 or snmpTrapOID.0
shall be determined by using the rules in section 3.1 of
[RFC3584]"
DEFVAL { 0 }
::= { alarmModelEntry 4 }
alarmModelVarbindValue OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The value that the varbind indicated by
alarmModelVarbindIndex takes to indicate
that the alarm has entered this state.
If alarmModelVarbindIndex has a value of 0, so
MUST alarmModelVarbindValue.
"
DEFVAL { 0 }
::= { alarmModelEntry 5 }
alarmModelDescription OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"A brief description of this alarm and state suitable
to display to operators."
DEFVAL { "" }
::= { alarmModelEntry 6 }
alarmModelSpecificPointer OBJECT-TYPE
SYNTAX RowPointer
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"If no additional, model-specific Alarm MIB is supported by
the system the value of this object is `0.0’and attempts
to set it to any other value MUST be rejected appropriately.
When a model-specific Alarm MIB is supported, this object
MUST refer to the first accessible object in a corresponding
row of the model definition in one of these model-specific
MIB and attempts to set this object to { 0 0 } or any other
value MUST be rejected appropriately."
DEFVAL { zeroDotZero }
::= { alarmModelEntry 7 }
alarmModelVarbindSubtree OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The name portion of each VarBind in the notification,
in order, is compared to the value of this object.
If the name is equal to or a subtree of the value
of this object, for purposes of computing the value
of AlarmActiveResourceID the ’prefix’ will be the
matching portion, and the ’indexes’ will be any
remainder. The examination of varbinds ends with
the first match. If the value of this object is 0.0,
then the first varbind, or in the case of v2, the
first varbind after the timestamp and the trap
OID, will always be matched.
"
DEFVAL { zeroDotZero }
::= { alarmModelEntry 8 }
alarmModelResourcePrefix OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The value of AlarmActiveResourceId is computed
by appending any indexes extracted in accordance
with the description of alarmModelVarbindSubtree
onto the value of this object. If this object’s
value is 0.0, then the ’prefix’ extracted is used
instead.
"
DEFVAL { zeroDotZero }
::= { alarmModelEntry 9 }
alarmModelRowStatus OBJECT-TYPE
SYNTAX RowStatus
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"Control for creating and deleting entries. Entries may be
modified while active. Alarms whose alarmModelRowStatus is
not active will not appear in either the alarmActiveTable
or the alarmClearTable. Setting this object to notInService
cannot be used as an alarm suppression mechanism. Entries
that are notInService will disappear as described in RFC2579.
This row can not be modified while it is being
referenced by a value of alarmActiveModelPointer. In these
cases, an error of `inconsistentValue’ will be returned to
the manager.
This entry may be deleted while it is being
referenced by a value of alarmActiveModelPointer. This results
in the deletion of this entry and entries in the active alarms
referencing this entry via an alarmActiveModelPointer.
As all read-create objects in this table have a DEFVAL clause,
there is no requirement that any object be explicitly set
before this row can become active. Note that a row consisting
only of default values is not very meaningful."
::= { alarmModelEntry 10 }
-- Active Alarm Table --
alarmActiveLastChanged OBJECT-TYPE
SYNTAX TimeTicks
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of sysUpTime at the time of the last
creation or deletion of an entry in the alarmActiveTable.
If the number of entries has been unchanged since the
last re-initialization of the local network management
subsystem, then this object contains a zero value."
::= { alarmActive 1 }
alarmActiveOverflow OBJECT-TYPE
SYNTAX Counter32
UNITS "active alarms"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of active alarms that have not been put into
the alarmActiveTable since system restart as a result
of extreme resource constraints."
::= { alarmActive 5 }
alarmActiveTable OBJECT-TYPE
SYNTAX SEQUENCE OF AlarmActiveEntry
MAX-ACCESS not-accessible