RFC 1451
Manager-to-Manager Management Information Base
Manager-to-Manager Management Information Base 🎀
okay bestie, this is RFC 1451, published in April 1993 by the Network Working Group 🌸 It's a standards track protocol doc (the status section calls it an IAB standards track protocol), and four people wrote it: J. Case from SNMP Research, Inc., K. McCloghrie from Hughes LAN Systems, M. Rose from Dover Beach Consulting, Inc., and S. Waldbusser from Carnegie Mellon University. The title block doesn't list any RFCs that it obsoletes or updates, so nothing's being replaced or patched here 💅
Status of this Memo ✨
This RFC specifies an IAB standards track protocol for the Internet community, and it's requesting discussion and suggestions for improvements 🫶 For the standardization state and status of this protocol, check the current edition of the "IAB Official Protocol Standards." Distribution of this memo is unlimited, so share it with everyone 🦋
Table of Contents 📑
1 Introduction .......................................... 2
1.1 A Note on Terminology ............................... 2
2 Overview .............................................. 3
2.1 A SNMPv2 Entity Acting in a Dual Role ............... 3
2.2 Alarms, Events, and Notifications ................... 3
2.3 Access Control ...................................... 4
3 Definitions ........................................... 6
3.1 The Alarm Group ..................................... 7
3.1.1 Alarm-Related Notifications ....................... 20
3.2 The Event Group ..................................... 21
3.3 Conformance Information ............................. 29
3.3.1 Compliance Statements ............................. 29
3.3.2 Units of Conformance .............................. 29
4 Acknowledgements ...................................... 31
5 References ............................................ 35
6 Security Considerations ............................... 36
7 Authors' Addresses .................................... 361. Introduction 💖
okay so a network management system has a few parts 🧚 First there are several (potentially many) nodes, and each one has a processing entity called an agent, which can get to management instrumentation. Then there's at least one management station, plus a management protocol that carries management information between the agents and the management stations. The protocol runs under an administrative framework that defines both authentication and authorization policies, so it's not just vibes, there are rules 👑
Network management stations run management applications that monitor and control network elements. Network elements are things like hosts, routers, terminal servers, etc., and they get monitored and controlled through access to their management information 🔥
The management information is seen as a collection of managed objects, living in a virtual information store called the Management Information Base (MIB). Related objects get grouped into MIB modules, and those modules are written in a subset of OSI's Abstract Syntax Notation One (ASN.1) [1], which is called the Structure of Management Information (SMI) [2] 🌈
The management protocol is version 2 of the Simple Network Management Protocol [3]. It handles exchanging messages that carry management information between agents and management stations, and that includes messages between management stations too 🦋 The whole point of this document is to define managed objects that describe how an SNMPv2 entity behaves when it's acting in both a manager role and an agent role. Main character energy, honestly ✨
1.1. A Note on Terminology 🍓
so, for the sake of explaining things, the original Internet-standard Network Management Framework (described in RFCs 1155, 1157, and 1212) is called the SNMP version 1 framework (SNMPv1). The current framework is called the SNMP version 2 framework (SNMPv2) 💜
2. Overview 🌸
The purpose of this MIB is to coordinate between multiple management stations. In other words, it gives the means for the controlling and monitoring functions of network management to get spread out across multiple management stations 💅 That kind of distribution helps SNMPv2-based network management scale up to very large networks, or to networks made of multiple interconnected administrations. Specifically, this MIB lets one management station request management services from another management station 🫶
2.1. A SNMPv2 Entity Acting in a Dual Role 👑
A management station that provides services to other management station(s) is an SNMPv2 entity that acts as both manager and agent at the same time 🤯 The requests for service come in through its agent role (with respect to the managed objects defined in this MIB), and the requested services get carried out through its manager role. It's giving double agent, but make it iconic 🕵️♀️
2.2. Alarms, Events, and Notifications 🔥
In this initial version, this MIB defines the concepts of "alarms", "events", and "notifications" ✨ Each alarm is a specific condition that gets detected by periodically monitoring the value of a specific management information variable (at a configured sampling interval). One example is when the monitored variable falls outside a configured range. Each alarm condition triggers an event, and each event can cause (one or more) notifications to be reported to other management stations using the Inform-Request PDU 📬
Specifically, this MIB defines three MIB tables and a number of scalar objects. The three tables are the Alarm Table, the Event Table, and the Notification Table 🎀
2.3. Access Control 🔐
The Administrative Model for SNMPv2 document [4] includes an access control model, and that model must not be subverted by letting people reach management information variables through the Alarm table 🙅♀️ Put simply, access to a monitored variable through the Alarm table must be controlled according to the identity of the management station that's accessing that particular entry in the Alarm table 💖
An entry in the Alarm table lets you configure the sampling of a MIB variable's value, in the MIB view linked to the specified context (which can point at object resources that are either local or remote). The sampling happens by (conceptually or actually) issuing an SNMPv2 request to retrieve the variable's value. That request is authenticated and/or protected from disclosure according to a source party and destination party pair that has access to the indicated context 🧚
So, to provide the required access control, the initial MIB view that gets assigned by convention to parties on SNMPv2 entities that implement the snmpAlarmTable must include this component:
viewSubtree = { snmpAlarm }
viewStatus = { excluded }
viewMask = { ''H }Then the MIB view tied to the context, requestContext (the one a requesting management station can access), can be set up to include specific Alarm table entries. Those are the ones tied to the contexts that the requesting management station has access to 🌈
To give a requestContext access to the sampling context sampleContext, the following family of view subtrees would be included for requestContext on the SNMPv2 entity acting in a dual role:
{ snmpAlarmEntry WILDCARD sampleContext }This would get configured in the party MIB [5] like so:
contextIdentity = { requestContext }
contextViewIndex = { ViewIndex }
viewIndex = { ViewIndex }
viewSubtree = { snmpAlarmEntry 0 sampleContext }
viewStatus = { included }
viewMask = { 'FFEF'H } -- specifies wildcard for column3. Definitions 💅
Here's the module itself 🦋 This is the ASN.1 for SNMPv2-M2M-MIB, so you can see how everything's named and where it sits in the tree.
SNMPv2-M2M-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, NOTIFICATION-TYPE,
Integer32, Counter32, snmpModules
FROM SNMPv2-SMI
DisplayString, InstancePointer, RowStatus, TimeStamp
FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP
FROM SNMPv2-CONF
contextIdentity
FROM SNMPv2-PARTY-MIB;
snmpM2M MODULE-IDENTITY
LAST-UPDATED "9304010000Z"
ORGANIZATION "IETF SNMPv2 Working Group"
CONTACT-INFO
" Steven Waldbusser
Postal: Carnegie Mellon University
4910 Forbes Ave
Pittsburgh, PA 15213
Tel: +1 412 268 6628
Fax: +1 412 268 4987
E-mail: waldbusser@cmu.edu"
DESCRIPTION
"The Manager-to-Manager MIB module."
::= { snmpModules 2 }
snmpM2MObjects OBJECT IDENTIFIER ::= { snmpM2M 1 }
-- the alarm group
--
-- a collection of objects allowing the description and
-- configuration of threshold alarms from a SNMPv2 entity
-- acting in a dual role.
snmpAlarm OBJECT IDENTIFIER ::= { snmpM2MObjects 1 }okay bestie, we're deep in the MIB module now and the snmpAlarm stuff is giving main character energy 💅✨
-- This Alarm mechanism periodically takes statistical samples
-- from variables available via SNMPv2 and compares them to
-- thresholds that have been configured. The alarm table
-- stores configuration entries that each define a variable,
-- polling period, and threshold parameters. If a sample is
-- found to cross the threshold values, an event is generated.
-- Only variables that resolve to an ASN.1 primitive type of
-- INTEGER (Integer32, Counter32, Gauge32, TimeTicks,
-- Counter64, or UInteger32) may be monitored in this way.
--
-- This function has a hysteresis mechanism to limit the
-- generation of events. This mechanism generates one event
-- as a threshold is crossed in the appropriate direction. No
-- more events are generated for that threshold until the
-- opposite threshold is crossed.
--
-- In the case of sampling a deltaValue, an entity may
-- implement this mechanism with more precision if it takes a
-- delta sample twice per period, each time comparing the sum
-- of the latest two samples to the threshold. This allows
-- the detection of threshold crossings that span the sampling
-- boundary. Note that this does not require any special
-- configuration of the threshold value. It is suggested that
-- entities implement this more precise algorithm.
--
snmpAlarmNextIndex OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The index number of the next appropriate
unassigned entry in the snmpAlarmTable. The value
0 indicates that no unassigned entries are
available.
A management station should create new entries in
the snmpAlarmTable using this algorithm: first,
issue a management protocol retrieval operation to
determine the value of snmpAlarmNextIndex; and,
second, issue a management protocol set operation
to create an instance of the snmpAlarmStatus
object setting its value to `createAndGo' or
`createAndWait' (as specified in the description
of the RowStatus textual convention)."
::= { snmpAlarm 1 }so the big picture here is 🦋 the alarm mechanism grabs samples from SNMPv2 variables and checks them against thresholds you've set up. the table is where each config lives, with a variable, a polling period, and the threshold numbers. only the INTEGER-flavoured types can get monitored this way (Integer32, Counter32, Gauge32, TimeTicks, Counter64, UInteger32), so no sneaking in other types 🙅♀️
the hysteresis bit is lowkey genius 🧠. a threshold only fires one event when it's crossed in the right direction, and then it goes quiet until the opposite threshold gets crossed. no event spam, no drama 💅
there's also a highkey extra-precise option for deltaValue sampling 🎀. an entity can take a delta sample twice per period and compare the sum of the latest two samples to the threshold, so it catches crossings that happen right across a sampling boundary. no special threshold config needed for that. the text says it's suggested (not required) that entities go this route, so it's a glow-up, not a must ✨
and for snmpAlarmNextIndex 🍓: it tells the management station which index is the next free one. 0 means there's no free slot left. to make a new row, the station first reads this value, then does a set to create the snmpAlarmStatus instance using createAndGo or createAndWait (the RowStatus textual convention spells those out).
snmpAlarmTable OBJECT-TYPE
SYNTAX SEQUENCE OF SnmpAlarmEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A list of snmpAlarm entries."
::= { snmpAlarm 2 }
snmpAlarmEntry OBJECT-TYPE
SYNTAX SnmpAlarmEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A list of parameters that set up a periodic
sampling query to check for alarm conditions. The
contextIdentity included in the INDEX clause is
the context to which the sampling queries are
directed."
INDEX { contextIdentity, snmpAlarmIndex }
::= { snmpAlarmTable 1 }
SnmpAlarmEntry ::= SEQUENCE {
snmpAlarmIndex INTEGER,
snmpAlarmVariable InstancePointer,
snmpAlarmInterval Integer32,
snmpAlarmSampleType INTEGER,
snmpAlarmValue Integer32,
snmpAlarmStartupAlarm INTEGER,
snmpAlarmRisingThreshold Integer32,
snmpAlarmFallingThreshold Integer32,
snmpAlarmRisingEventIndex INTEGER,
snmpAlarmFallingEventIndex INTEGER,
snmpAlarmUnavailableEventIndex INTEGER,
snmpAlarmStatus RowStatus
}
snmpAlarmIndex OBJECT-TYPE
SYNTAX INTEGER (1..65535)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An index that uniquely identifies an entry in the
snmpAlarm table for a particular sampling context.
Each such entry defines a diagnostic sample at a
particular interval for a variable in the
particular context's object resources."
::= { snmpAlarmEntry 1 }the table itself 🌸 is just a list of alarm entries, and each row is basically a little sampling job. the row is keyed by contextIdentity plus snmpAlarmIndex, and contextIdentity is the context the sampling queries get aimed at. snmpAlarmIndex runs from 1 to 65535 and picks out one diagnostic sample for one variable inside that context's object resources 🦋
then the SnmpAlarmEntry SEQUENCE lists out every column in the row, from snmpAlarmIndex all the way to snmpAlarmStatus (which is a RowStatus) 💖
snmpAlarmVariable OBJECT-TYPE
SYNTAX InstancePointer
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The object identifier of the particular variable
to be sampled. Only variables that resolve to an
ASN.1 primitive type of INTEGER (Integer32,
Counter32, Gauge32, TimeTicks, Counter64, or
UInteger32) may be sampled.
If it is detected by an error response of
authorizationError, noSuchObject, or
noSuchInstance that the variable name of an
established snmpAlarmEntry is no longer available
in the sampling context, a single
snmpObjectUnavailableAlarm event is generated and
the status of this snmpAlarmEntry is set to
`destroy'. Likewise, if the syntax of the
variable retrieved by the query is not Integer32,
Counter32, Gauge32, TimeTicks, Counter64, or
UInteger32, the same actions will be taken.
If the SNMPv2 entity acting in a dual role detects
that the sampled value can not be obtained due to
lack of response to management queries, it should
either:
1) Set the status of this snmpAlarmEntry to
`destroy', if it is determined that further
communication is not possible;
or,
2) Delete the associated snmpAlarmValue
instance (but not the entire conceptual row),
and continue to attempt to sample the
variable and recreate the associated
snmpAlarmValue instance should communication
be reestablished.
An attempt to modify this object will fail with an
`inconsistentValue' error if the associated
snmpAlarmStatus object would be equal to `active'
both before and after the modification attempt."
::= { snmpAlarmEntry 2 }okay this one is the drama queen 😭🔥. snmpAlarmVariable is the OID of the thing being sampled, and once again it has to be one of those INTEGER-ish types. if the variable goes missing (the error comes back as authorizationError, noSuchObject, or noSuchInstance), or its syntax stops matching, you get a single snmpObjectUnavailableAlarm event and the row's status gets set to destroy 💀
if the SNMPv2 entity is acting in a dual role and the value can't be fetched because nobody's answering, it has two options. option one: set the row to destroy, but only if it's decided that talking to that thing is never happening again. option two: delete just the snmpAlarmValue instance (not the whole row), keep trying to sample, and rebuild that value once communication comes back 🫶
and the last rule 🙈: you can't change this object while its row is active, both before and after the change, because you'd get an inconsistentValue error.
snmpAlarmInterval OBJECT-TYPE
SYNTAX Integer32
UNITS "seconds"
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The interval in seconds over which the data is
sampled and compared with the rising and falling
thresholds. When setting this object and the
sampling type is `deltaValue', care should be
taken to ensure that the change during this
interval of the variable being sampled will not
exceed the (-2^31...2^31-1) range of the
snmpAlarmValue.
An attempt to modify this object will fail with an
`inconsistentValue' error if the associated
snmpAlarmStatus object would be equal to `active'
both before and after the modification attempt."
::= { snmpAlarmEntry 3 }
snmpAlarmSampleType OBJECT-TYPE
SYNTAX INTEGER {
absoluteValue(1),
deltaValue(2)
}
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The method of sampling the selected variable and
calculating the value to be compared against the
thresholds. If the value of this object is
`absoluteValue', the value of the selected
variable at the end of the sampling interval will
be compared directly with both the
snmpAlarmRisingThreshold and the
snmpAlarmFallingThreshold values. If the value of
this object is `deltaValue', the value of the
selected variable at the end of the sampling
interval will be subtracted from its value at the
end of the previous sampling interval, and the
difference compared with both the
snmpAlarmRisingThreshold and the
snmpAlarmFallingThreshold values.
An attempt to modify this object will fail with an
`inconsistentValue' error if the associated
snmpAlarmStatus object would be equal to `active'
both before and after the modification attempt."
DEFVAL { deltaValue }
::= { snmpAlarmEntry 4 }snmpAlarmInterval 🕰️ is how many seconds each sampling window lasts, and the value gets compared with the rising and falling thresholds at the end of it. if you're using deltaValue, double-check that the change across one interval fits inside the (-2^31...2^31-1) range of snmpAlarmValue, because otherwise it won't fit 🙃. same rule as before: no changing it while the row is active before and after.
snmpAlarmSampleType 🧁 picks how the number gets calculated. absoluteValue compares the variable's value at the end of the window straight against both thresholds. deltaValue subtracts the value from the end of the previous window and compares the difference instead. the default is deltaValue 💜
snmpAlarmValue OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of the statistic during the last
sampling period. The value during the current
sampling period is not made available until the
period is completed. If the value of the
statistic does not fit in the signed 32 bit
representation of this object, it should be
truncated in an implementation specific manner.
Note that if the associated snmpAlarmSampleType is
set to `deltaValue', the value of this object is
the difference in the sampled variable since the
last sample.
This object will be created by the SNMPv2 entity
acting in a dual role when this entry is set to
`active', and the first sampling period has
completed. It may be created and deleted at other
times by the SNMPv2 entity acting in a dual role
when the sampled value can not be obtained, as
specified in the snmpAlarmVariable object."
::= { snmpAlarmEntry 5 }and snmpAlarmValue 📊 is the most recent finished sampling period's result. the current window isn't visible until it wraps up ⏳. if the number is too big for a signed 32-bit slot, it gets truncated in whatever way the implementation picks. with deltaValue, this is the difference since the last sample. it only shows up once the row is active and the first period is done, and it can get created and deleted again if sampling stops working (the snmpAlarmVariable section explains the details) 🌈
Okay bestie, we're deep in the alarm table now, and snmpAlarmStartupAlarm is literally the moment-one decider 🦋
snmpAlarmStartupAlarm OBJECT-TYPE
SYNTAX INTEGER {
risingAlarm(1),
fallingAlarm(2),
risingOrFallingAlarm(3)
}
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The alarm that may be sent when this entry is
first set to `active'. If the first sample after
this entry becomes active is greater than or equal
to the risingThreshold and snmpAlarmStartupAlarm
is equal to `risingAlarm' or
`risingOrFallingAlarm', then a single rising alarm
will be generated. If the first sample after this
entry becomes active is less than or equal to the
fallingThreshold and snmpAlarmStartupAlarm is
equal to `fallingAlarm' or `risingOrFallingAlarm',
then a single falling alarm will be generated.
Note that a snmpObjectUnavailableAlarm is sent
upon startup whenever it is applicable,
independent of the setting of
snmpAlarmStartupAlarm.
An attempt to modify this object will fail with an
`inconsistentValue' error if the associated
snmpAlarmStatus object would be equal to `active'
both before and after the modification attempt."
DEFVAL { risingOrFallingAlarm }
::= { snmpAlarmEntry 6 }
snmpAlarmRisingThreshold OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"A threshold for the sampled statistic. When the
current sampled value is greater than or equal to
this threshold, and the value at the last sampling
interval was less than this threshold, a single
event will be generated. A single event will also
be generated if the first sample after this entry
becomes active is greater than or equal to this
threshold and the associated snmpAlarmStartupAlarm
is equal to `risingAlarm' or
`risingOrFallingAlarm'.
After a rising event is generated, another such
event will not be generated until the sampled
value falls below this threshold and reaches the
snmpAlarmFallingThreshold.
An attempt to modify this object will fail with an
`inconsistentValue' error if the associated
snmpAlarmStatus object would be equal to `active'
both before and after the modification attempt."
::= { snmpAlarmEntry 7 }
snmpAlarmFallingThreshold OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"A threshold for the sampled statistic. When the
current sampled value is less than or equal to
this threshold, and the value at the last sampling
interval was greater than this threshold, a single
event will be generated. A single event will also
be generated if the first sample after this entry
becomes active is less than or equal to this
threshold and the associated snmpAlarmStartupAlarm
is equal to `fallingAlarm' or
`risingOrFallingAlarm'.
After a falling event is generated, another such
event will not be generated until the sampled
value rises above this threshold and reaches the
snmpAlarmRisingThreshold.
An attempt to modify this object will fail with an
`inconsistentValue' error if the associated
snmpAlarmStatus object would be equal to `active'
both before and after the modification attempt."
::= { snmpAlarmEntry 8 }
snmpAlarmRisingEventIndex OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The index of the snmpEventEntry that is used when
a rising threshold is crossed. The snmpEventEntry
identified by a particular value of this index is
the same as identified by the same value of the
snmpEventIndex object. If there is no
corresponding entry in the snmpEventTable, then no
association exists. In particular, if this value
is zero, no associated event will be generated, as
zero is not a valid snmpEventIndex.
An attempt to modify this object will fail with an
`inconsistentValue' error if the associated
snmpAlarmStatus object would be equal to `active'
both before and after the modification attempt."
::= { snmpAlarmEntry 9 }
snmpAlarmFallingEventIndex OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The index of the snmpEventEntry that is used when
a falling threshold is crossed. The
snmpEventEntry identified by a particular value of
this index is the same as identified by the same
value of the snmpEventIndex object. If there is
no corresponding entry in the snmpEventTable, then
no association exists. In particular, if this
value is zero, no associated event will be
generated, as zero is not a valid snmpEventIndex.
An attempt to modify this object will fail with an
`inconsistentValue' error if the associated
snmpAlarmStatus object would be equal to `active'
both before and after the modification attempt."
::= { snmpAlarmEntry 10 }
snmpAlarmUnavailableEventIndex OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The index of the snmpEventEntry that is used when
a variable becomes unavailable. The
snmpEventEntry identified by a particular value of
this index is the same as identified by the same
value of the snmpEventIndex object. If there is
no corresponding entry in the snmpEventTable, then
no association exists. In particular, if this
value is zero, no associated event will be
generated, as zero is not a valid snmpEventIndex.
An attempt to modify this object will fail with an
`inconsistentValue' error if the associated
snmpAlarmStatus object would be equal to `active'
both before and after the modification attempt."
::= { snmpAlarmEntry 11 }
snmpAlarmStatus OBJECT-TYPE
SYNTAX RowStatus
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The status of this snmpAlarm entry. This object
may not be set to `active' unless the following
columnar objects exist in this row:
snmpAlarmVariable, snmpAlarmInterval,
snmpAlarmSampleType, snmpAlarmStartupAlarm,
snmpAlarmRisingThreshold,
snmpAlarmFallingThreshold,
snmpAlarmRisingEventIndex,
snmpAlarmFallingEventIndex, and
snmpAlarmUnavailableEventIndex."
::= { snmpAlarmEntry 12 }Ngl the startup alarm is so iconic 💅 When the entry first goes active, the first sample decides what happens. If it's at or above the rising threshold and the setting is risingAlarm or risingOrFallingAlarm, you get one rising alarm. If it's at or below the falling threshold and the setting is fallingAlarm or risingOrFallingAlarm, you get one falling alarm. The default setting is risingOrFallingAlarm 💖 And the unavailable alarm still goes out at startup whenever it applies, no matter what the startup setting is 🙈
Also, you can't change any of these while the row is active without getting an inconsistentValue error. Bestie, that's a whole vibe check 🫶
The thresholds are giving hysteresis energy 🌸 A rising event fires when the sample climbs to the rising threshold from below, and then nothing else rising-wise happens until the value drops under that threshold and reaches the falling threshold. Falling events work the mirror-image way. Same startup rule applies, so the first sample can trigger one too.
-- alarm-related notifications
snmpAlarmNotifications
OBJECT IDENTIFIER ::= { snmpAlarm 3 }
snmpRisingAlarm NOTIFICATION-TYPE
OBJECTS { snmpAlarmVariable, snmpAlarmSampleType,
snmpAlarmValue, snmpAlarmRisingThreshold }
STATUS current
DESCRIPTION
"An event that is generated when an alarm entry
crosses its rising threshold. The instances of
those objects contained within the varbind list
are those of the alarm entry which generated this
event."
::= { snmpAlarmNotifications 1 }
snmpFallingAlarm NOTIFICATION-TYPE
OBJECTS { snmpAlarmVariable, snmpAlarmSampleType,
snmpAlarmValue, snmpAlarmFallingThreshold }
STATUS current
DESCRIPTION
"An event that is generated when an alarm entry
crosses its falling threshold. The instances of
those objects contained within the varbind list
are those of the alarm entry which generated this
event."
::= { snmpAlarmNotifications 2 }
snmpObjectUnavailableAlarm NOTIFICATION-TYPE
OBJECTS { snmpAlarmVariable }
STATUS current
DESCRIPTION
"An event that is generated when a variable
monitored by an alarm entry becomes unavailable.
The instance of snmpAlarmVariable contained within
the varbind list is the one associated with the
alarm entry which generated this event."
::= { snmpAlarmNotifications 3 }Three notifications, three vibes 🎀 snmpRisingAlarm and snmpFallingAlarm are sent when an alarm entry crosses its rising or falling threshold, and snmpObjectUnavailableAlarm is sent when a monitored variable goes unavailable. In every case, the varbind instances are the ones from the alarm entry that fired it 🧚
Now for the event group, which is where the alarms get their voice 📣
-- the event group
--
-- a collection of objects allowing the description and
-- configuration of events from a SNMPv2 entity acting
-- in a dual role.
snmpEvent OBJECT IDENTIFIER ::= { snmpM2MObjects 2 }
-- The snmpEvent table defines the set of events generated on
-- a SNMPv2 entity acting in a dual role. Each entry in the
-- snmpEventTable associates an event type with the
-- notification method and associated parameters. Some
-- snmpEvent entries are fired by an associated condition in
-- the snmpAlarmTable. Others are fired on behalf of
-- conditions defined in the NOTIFICATION-TYPE macro. The
-- snmpNotificationTable defines notifications that should
-- occur when an associated event is fired.
snmpEventNextIndex OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The index number of the next appropriate
unassigned entry in the snmpEventTable. The value
0 indicates that no unassigned entries are
available.The event table is the glue ✨ It links each event type to a notification method and its parameters. Some events get fired by alarm-table conditions, others by conditions from the NOTIFICATION-TYPE macro, and the notification table is where you spell out what should happen when an event fires. Bestie, we're about to meet the rest of the crew 🌈
okay so we're picking up mid-description of snmpEventNextIndex 💅 this is the part where the management station does the whole create dance 🦋
A management station should create new entries in
the snmpEventTable using this algorithm: first,
issue a management protocol retrieval operation to
determine the value of snmpEventNextIndex; and,
second, issue a management protocol set operation
to create an instance of the snmpEventStatus
object setting its value to `createAndWait' or
'createAndGo'."
::= { snmpEvent 1 }
snmpEventTable OBJECT-TYPE
SYNTAX SEQUENCE OF SnmpEventEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A list of events."
::= { snmpEvent 2 }
snmpEventEntry OBJECT-TYPE
SYNTAX SnmpEventEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A set of parameters that describe an event that
is generated when certain conditions are met."
INDEX { snmpEventIndex }
::= { snmpEventTable 1 }
SnmpEventEntry ::= SEQUENCE {
snmpEventIndex INTEGER,
snmpEventID OBJECT IDENTIFIER,
snmpEventDescription DisplayString,
snmpEventEvents Counter32,
snmpEventLastTimeSent TimeStamp,
snmpEventStatus RowStatus
}
snmpEventIndex OBJECT-TYPE
SYNTAX INTEGER (1..65535)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An index that uniquely identifies an entry in the
snmpEvent table. Each such entry defines an event
generated when the appropriate conditions occur."
::= { snmpEventEntry 1 }
snmpEventID OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The authoritative identification of the event
type generated by this entry. This variable
occurs as the second varbind of an InformRequest-
PDU. If this OBJECT IDENTIFIER maps to a
NOTIFICATION-TYPE the sender will place the
objects listed in the NOTIFICATION-TYPE in the
varbind list."
::= { snmpEventEntry 2 }
snmpEventDescription OBJECT-TYPE
SYNTAX DisplayString (SIZE (0..127))
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"A comment describing this snmpEvent entry."
::= { snmpEventEntry 3 }
snmpEventEvents OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of events caused by event generators
associated with this snmpEvent entry."
::= { snmpEventEntry 4 }
snmpEventLastTimeSent OBJECT-TYPE
SYNTAX TimeStamp
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of sysUpTime at the time this snmpEvent
entry last generated an event. If this entry has
not generated any events, this value will be
zero."
DEFVAL { 0 }
::= { snmpEventEntry 5 }
snmpEventStatus OBJECT-TYPE
SYNTAX RowStatus
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The status of this snmpEvent entry. This object
may not be set to `active' unless the following
columnar objects exist in this row: snmpEventID,
snmpEventDescription, snmpEventEvents, and
snmpEventLastTimeSent.
Setting an instance of this object to the value
'destroy' has the effect of invalidating any/all
entries in the snmpEventTable, and the
snmpEventNotifyTable which reference the
corresponding snmpEventEntry."
::= { snmpEventEntry 6 }
snmpEventNotifyMinInterval OBJECT-TYPE
SYNTAX Integer32
UNITS "seconds"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The minimum interval that the SNMPv2 entity
acting in a dual role will wait before
retransmitting an InformRequest-PDU. This object
specifies the minimal value supported by the
SNMPv2 entity acting in a dual role, based on
resource or implementation constraints.
For a particular entry in the
snmpEventNotifyTable, if the associated
snmpEventNotifyIntervalRequested variable is
greater than this object, the
snmpEventNotifyIntervalRequested value shall be
used as the minimum interval for retransmissions
of InformRequest-PDUs sent on behalf of that
entry."
::= { snmpEvent 3 }
snmpEventNotifyMaxRetransmissions OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The maximum number of time that the SNMPv2 entity
acting in a dual role will retransmit an
InformRequest-PDU. This object specifies the
maximal value supported by the SNMPv2 entity
acting in a dual role, based on resource or
implementation constraints.
For a particular entry in the
snmpEventNotifyTable, if the associated
snmpEventNotifyRetransmissionsRequested variable
is less than this object, the
snmpEventNotifyRetransmissionsRequested value
shall be used as the retransmission count for
InformRequest-PDUs sent on behalf of that entry."
::= { snmpEvent 4 }
-- The snmpEventNotifyTable is used to configure the
-- destination and type of notifications sent by a SNMPv2
-- entity acting in a manager role when a particular event
-- is triggered.
snmpEventNotifyTable OBJECT-TYPE
SYNTAX SEQUENCE OF SnmpEventNotifyEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A list of protocol configuration entries for
event notifications from this entity."
::= { snmpEvent 5 }
snmpEventNotifyEntry OBJECT-TYPE
SYNTAX SnmpEventNotifyEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A set of parameters that describe the type and
destination of InformRequest-PDUs sent for a
particular event. The snmpEventIndex in this
entry's INDEX clause identifies the snmpEventEntry
which, when triggered, will generate a
notification as configured in this entry. The
contextIdentity in this entry's INDEX clause
identifies the context to which a notification
will be sent."
INDEX { snmpEventIndex, contextIdentity }
::= { snmpEventNotifyTable 1 }
SnmpEventNotifyEntry ::= SEQUENCE {
snmpEventNotifyIntervalRequested Integer32,
snmpEventNotifyRetransmissionsRequested Integer32,
snmpEventNotifyLifetime Integer32,
snmpEventNotifyStatus RowStatus
}
snmpEventNotifyIntervalRequested OBJECT-TYPE
SYNTAX Integer32
UNITS "seconds"
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The requested interval for retransmission of
Inform PDUs generated on the behalf of this entry.
This variable will be the actual interval used
unless the snmpEventNotifyMinInterval is greater
than this object, in which case the interval shall
be equal to snmpEventNotifyMinInterval."
DEFVAL { 30 }
::= { snmpEventNotifyEntry 1 }
snmpEventNotifyRetransmissionsRequested OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The requested number of retransmissions of an
InformRequest-PDU generated on behalf of this
entry.
This variable will be the actual number of
retransmissions used unless the
snmpEventNotifyMaxRetransmissions is less than
this object, in which case the retransmission
count shall be equal to
snmpEventNotifyMaxRetransmissions."
DEFVAL { 5 }
::= { snmpEventNotifyEntry 2 }
snmpEventNotifyLifetime OBJECT-TYPE
SYNTAX Integer32
UNITS "seconds"
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The number of seconds this entry shall live until
the corresponding instance of
snmpEventNotifyStatus is set to 'destroy'. This
value shall count down to zero, at which time the
corresponding instance of snmpEventNotifyStatus
will be set to 'destroy'. Any management station
that is using this entry must periodically refresh
this value to ensure the continued delivery of
events."
DEFVAL { 86400 }
::= { snmpEventNotifyEntry 3 }
snmpEventNotifyStatus OBJECT-TYPE
SYNTAX RowStatus
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The state of this snmpEventNotifyEntry. This
object may not be set to `active' unless the
following columnar objects exist in this row:
snmpEventNotifyIntervalRequested,
snmpEventNotifyRetransmissionsRequested, and
snmpEventNotifyLifetime."
::= { snmpEventNotifyEntry 4 }
-- conformance information
snmpM2MConformance
OBJECT IDENTIFIER ::= { snmpM2M 2 }
snmpM2MCompliances
OBJECT IDENTIFIER ::= { snmpM2MConformance 1 }
snmpM2MGroups OBJECT IDENTIFIER ::= { snmpM2MConformance 2 }
-- compliance statements snmpM2MCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for SNMPv2 entities
which implement the Manager-to-Manager MIB."
MODULE -- this module
MANDATORY-GROUPS { snmpAlarmGroup, snmpEventGroup }
::= { snmpM2MCompliances 1 }
-- units of conformance
snmpAlarmGroup OBJECT-GROUP
OBJECTS { snmpAlarmNextIndex,
snmpAlarmVariable, snmpAlarmInterval,
snmpAlarmSampleType, snmpAlarmValue,
snmpAlarmStartupAlarm, snmpAlarmRisingThreshold,
snmpAlarmFallingThreshold,
snmpAlarmRisingEventIndex,
snmpAlarmFallingEventIndex,
snmpAlarmUnavailableEventIndex,
snmpAlarmStatus }
STATUS current
DESCRIPTION
"A collection of objects allowing the description
and configuration of threshold alarms from a
SNMPv2 entity acting in a dual role."
::= { snmpM2MGroups 1 }
snmpEventGroup OBJECT-GROUP
OBJECTS { snmpEventNextIndex,
snmpEventID, snmpEventDescription,
snmpEventEvents, snmpEventLastTimeSent,
snmpEventStatus, snmpEventNotifyMinInterval,
snmpEventNotifyMaxRetransmissions,
snmpEventNotifyIntervalRequested,
snmpEventNotifyRetransmissionsRequested,
snmpEventNotifyLifetime, snmpEventNotifyStatus }
STATUS current
DESCRIPTION
"A collection of objects allowing the description
and configuration of events from a SNMPv2 entity
acting in a dual role."
::= { snmpM2MGroups 2 }
END4. Acknowledgements ✨
Okay, big thank-yous 🫶 to the SNMP version 2 working group, whose comments made this whole thing better. Here's the squad:
Beth Adams, Network Management Forum
Steve Alexander, INTERACTIVE Systems Corporation
David Arneson, Cabletron Systems
Toshiya Asaba
Fred Baker, ACC
Jim Barnes, Xylogics, Inc.
Brian Bataille
Andy Bierman, SynOptics Communications, Inc.
Uri Blumenthal, IBM Corporation
Fred Bohle, Interlink
Jack Brown
Theodore Brunner, Bellcore
Stephen F. Bush, GE Information Services
Jeffrey D. Case, University of Tennessee, Knoxville
John Chang, IBM Corporation
Szusin Chen, Sun Microsystems
Robert Ching
Chris Chiotasso, Ungermann-Bass
Bobby A. Clay, NASA/Boeing
John Cooke, Chipcom
Tracy Cox, Bellcore
Juan Cruz, Datability, Inc.
David Cullerot, Cabletron Systems
Cathy Cunningham, Microcom
James R. (Chuck) Davin, Bellcore
Michael Davis, Clearpoint
Mike Davison, FiberCom
Cynthia DellaTorre, MITRE
Taso N. Devetzis, Bellcore
Manual Diaz, DAVID Systems, Inc.
Jon Dreyer, Sun Microsystems
David Engel, Optical Data Systems
Mike Erlinger, Lexcel
Roger Fajman, NIH
Daniel Fauvarque, Sun Microsystems
Karen Frisa, CMU
Shari Galitzer, MITRE
Shawn Gallagher, Digital Equipment Corporation
Richard Graveman, Bellcore
Maria Greene, Xyplex, Inc.
Michel Guittet, Apple
Robert Gutierrez, NASA
Bill Hagerty, Cabletron Systems
Gary W. Haney, Martin Marietta Energy Systems
Patrick Hanil, Nokia Telecommunications
Matt Hecht, SNMP Research, Inc.
Edward A. Heiner, Jr., Synernetics Inc.
Susan E. Hicks, Martin Marietta Energy Systems
Geral Holzhauer, Apple
John Hopprich, DAVID Systems, Inc.
Jeff Hughes, Hewlett-Packard
Robin Iddon, Axon Networks, Inc.
David Itusak
Kevin M. Jackson, Concord Communications, Inc.
Ole J. Jacobsen, Interop Company
Ronald Jacoby, Silicon Graphics, Inc.
Satish Joshi, SynOptics Communications, Inc.
Frank Kastenholz, FTP Software
Mark Kepke, Hewlett-Packard
Ken Key, SNMP Research, Inc.
Zbiginew Kielczewski, Eicon
Jongyeoi Kim
Andrew Knutsen, The Santa Cruz Operation
Michael L. Kornegay, VisiSoft
Deirdre C. Kostik, Bellcore
Cheryl Krupczak, Georgia Tech
Mark S. Lewis, Telebit
David Lin
David Lindemulder, AT&T/NCR
Ben Lisowski, Sprint
David Liu, Bell-Northern Research
John Lunny, The Wollongong Group
Robert C. Lushbaugh Martin, Marietta Energy Systems
Michael Luufer, BBN
Carl Madison, Star-Tek, Inc.
Keith McCloghrie, Hughes LAN Systems
Evan McGinnis, 3Com Corporation
Bill McKenzie, IBM Corporation
Donna McMaster, SynOptics Communications, Inc.
John Medicke, IBM Corporation
Doug Miller, Telebit
Dave Minnich, FiberCom
Mohammad Mirhakkak, MITRE
Rohit Mital, Protools
George Mouradian, AT&T Bell Labs
Patrick Mullaney, Cabletron Systems
Dan Myers, 3Com Corporation
Rina Nathaniel, Rad Network Devices Ltd.
Hien V. Nguyen, Sprint
Mo Nikain
Tom Nisbet
William B. Norton, MERIT
Steve Onishi, Wellfleet Communications, Inc.
David T. Perkins, SynOptics Communications, Inc.
Carl Powell, BBN
Ilan Raab, SynOptics Communications, Inc.
Richard Ramons, AT&T
Venkat D. Rangan, Metric Network Systems, Inc.
Louise Reingold, Sprint
Sam Roberts, Farallon Computing, Inc.
Kary Robertson, Concord Communications, Inc.
Dan Romascanu, Lannet Data Communications Ltd.
Marshall T. Rose, Dover Beach Consulting, Inc.
Shawn A. Routhier, Epilogue Technology Corporation
Chris Rozman
Asaf Rubissa, Fibronics
Jon Saperia, Digital Equipment Corporation
Michael Sapich
Mike Scanlon, Interlan
Sam Schaen, MITRE
John Seligson, Ultra Network Technologies
Paul A. Serice, Corporation for Open Systems
Chris Shaw, Banyan Systems
Timon Sloane
Robert Snyder, Cisco Systems
Joo Young Song
Roy Spitier, Sprint
Einar Stefferud, Network Management Associates
John Stephens, Cayman Systems, Inc.
Robert L. Stewart, Xyplex, Inc. (chair)
Kaj Tesink, Bellcore
Dean Throop, Data General
Ahmet Tuncay, France Telecom-CNET
Maurice Turcotte, Racal Datacom
Warren Vik, INTERACTIVE Systems Corporation
Yannis Viniotis
Steven L. Waldbusser, Carnegie Mellon Universitty
Timothy M. Walden, ACC
Alice Wang, Sun Microsystems
James Watt, Newbridge
Luanne Waul, Timeplex
Donald E. Westlake III, Digital Equipment Corporation
Gerry White
Bert Wijnen, IBM Corporation
Peter Wilson, 3Com Corporation
Steven Wong, Digital Equipment Corporation
Randy Worzella, IBM Corporation
Daniel Woycke, MITRE
Honda Wu
Jeff Yarnell, Protools
Chris Young, Cabletron
Kiho Yum, 3Com Corporation5. References 📚
[1] Information processing systems - Open Systems Interconnection - Specification of Abstract Syntax Notation One (ASN.1), International Organization for Standardization. International Standard 8824, (December, 1987).
[2] Case, J., McCloghrie, K., Rose, M., and Waldbusser, S., "Structure of Management Information for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1442, SNMP Research, Inc., Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon University, April 1993.
[3] Case, J., McCloghrie, K., Rose, M., and Waldbusser, S., "Protocol Operations for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1448, SNMP Research, Inc., Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon University, April 1993.
[4] Galvin, J., and McCloghrie, K., "Administrative Model for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1445, Trusted Information Systems, Hughes LAN Systems, April 1993.
[5] McCloghrie, K., and Galvin, J., "Party MIB for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1447, Hughes LAN Systems, Trusted Information Systems, April 1993.
6. Security Considerations 🔐
Okay bestie, this one is short and I need you to sit with it 😭 Security issues are not discussed in this memo.
Read that twice, babe. This memo is not talking about security at all. 💀
7. Authors' Addresses 💌
Jeffrey D. Case
SNMP Research, Inc.
3001 Kimberlin Heights Rd.
Knoxville, TN 37920-9716
US
Phone: +1 615 573 1434
Email: case@snmp.com
Keith McCloghrie
Hughes LAN Systems
1225 Charleston Road
Mountain View, CA 94043
US
Phone: +1 415 966 7934
Email: kzm@hls.com
Marshall T. Rose
Dover Beach Consulting, Inc.
420 Whisman Court
Mountain View, CA 94043-2186
US
Phone: +1 415 968 1052
Email: mrose@dbc.mtview.ca.us
Steven Waldbusser
Carnegie Mellon University
4910 Forbes Ave
Pittsburgh, PA 15213
US
Phone: +1 412 268 6628
Email: waldbusser@cmu.edu📦 where this page comes from
- ietf: rfc1451 1993-04
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms