RFC 1757
Remote Network Monitoring Management Information Base
RFC 1757: Remote Network Monitoring Management Information Base 🦋
okay bestie, let's start with the title block because it's the tea 🫖✨ This is RFC 1757, written by S. Waldbusser at Carnegie Mellon University and dated February 1995. It's on the Standards Track, so it's a real Internet standards-track protocol doc 🔥 It obsoletes RFC 1271, which means this one replaces the older version 💅 It doesn't update anything else.
Status of this Memo 🌸
this doc is an Internet standards track protocol for the Internet community, and it's asking for discussion and suggestions for improvements 🫶 for the current standardization state and status of this protocol, check the latest "Internet Official Protocol Standards" (STD 1) 📚 and yes, distribution of this memo is unlimited 🦋
Abstract 💜
this memo defines a chunk of the Management Information Base (MIB) for network management protocols in TCP/IP-based internets. specifically, it defines objects for managing remote network monitoring devices 🧚
Table of Contents 🍓
1. The Network Management Framework ...................... 2
2. Overview .............................................. 3
2.1 Remote Network Management Goals ...................... 3
2.2 Textual Conventions .................................. 5
2.3 Structure of MIB ..................................... 5
2.3.1 The Ethernet Statistics Group ...................... 6
2.3.2 The History Control Group .......................... 6
2.3.3 The Ethernet History Group ......................... 6
2.3.4 The Alarm Group .................................... 6
2.3.5 The Host Group ..................................... 6
2.3.6 The HostTopN Group ................................. 7
2.3.7 The Matrix Group ................................... 7
2.3.8 The Filter Group ................................... 7
2.3.9 The Packet Capture Group ........................... 7
2.3.10 The Event Group ................................... 7
3. Control of Remote Network Monitoring Devices .......... 7
3.1 Resource Sharing Among Multiple Management Stations .. 8
3.2 Row Addition Among Multiple Management Stations ...... 10
4. Conventions ........................................... 11
5. Definitions ........................................... 11
6. Acknowledgments ....................................... 89
7. References ............................................ 89
8. Security Considerations ............................... 90
9. Author's Address ...................................... 90
10. Appendix: Changes from RFC 1271 ...................... 911. The Network Management Framework 🎀
the Internet-standard Network Management Framework is made of three components... okay actually four 👀 here they are:
- STD 16, RFC 1155 [1] defines the SMI, the mechanisms for describing and naming objects so they can be managed 🧩
- STD 16, RFC 1212 [2] defines a more concise description mechanism, and it's wholly consistent with the SMI 💖
- STD 17, RFC 1213 [3] defines MIB-II, the core set of managed objects for the Internet suite of protocols 🌈
- STD 15, RFC 1157 [4] defines SNMP, the protocol used for network access to managed objects 🔥
the Framework also permits new objects to be defined for experimentation and evaluation 🧪✨
managed objects are accessed through a virtual information store called the Management Information Base, or MIB 🗂️ inside a given MIB module, objects are defined using RFC 1212's OBJECT-TYPE macro. every object has, at a minimum, a name, a syntax, an access-level, and an implementation-status 💅
the name is an object identifier, an administratively assigned name that specifies an object type. the object type plus an object instance uniquely identifies one specific instantiation of the object 🦋 for human convenience, we also often use a textual string called the object descriptor to refer to the object type 🫶
the syntax of an object type defines the abstract data structure for that object type, and the ASN.1[5] language is used for this 📐 RFC 1155 purposely restricts which ASN.1 constructs may be used, and that's explicitly for simplicity 🧸
the access-level of an object type defines whether it makes "protocol sense" to read and/or write the value of an instance of that object type. (this access-level is independent of any administrative authorization policy, so don't mix them up 🙈)
the implementation-status of an object type indicates whether the object is mandatory, optional, obsolete, or deprecated 🌟
2. Overview 🌍
remote network monitoring devices, often called monitors or probes, are instruments that exist to manage a network 🛰️ these probes are often stand-alone devices that devote significant internal resources to nothing but managing a network, and an organization may use many of them, one per network segment, to manage its internet 🍓 they can also be used by a network management service provider to reach a client network, which is often geographically remote 🧚
the objects in this document are meant to be an interface between an RMON agent and an RMON management application. they aren't meant for direct manipulation by humans. some users may tolerate directly displaying a few of these objects, but few will tolerate the complexity of manually manipulating them to accomplish row creation, so that work should be handled by the management application 💀
most objects here work for managing any type of network, but some are specific to Ethernet networks: the objects in the etherStatsTable, the etherHistoryTable, and some attributes of the filterPktStatus and capturBufferPacketStatus objects 🦋 the design lets similar objects be defined for other network types, and future versions of this document and additional documents are intended to define extensions for other network types such as Token Ring and FDDI 🌈
2.1. Remote Network Management Goals 💜
- Offline Operation 🌙: sometimes a management station won't be in constant contact with its remote monitoring devices. that can be by design, to lower communications costs (especially over a WAN or dialup link), or by accident when network failures get in the way between the station and the probe 😭
so this MIB lets a probe be configured to run diagnostics and collect statistics continuously, even when talking to the management station may not be possible or efficient 💖 the probe may then try to notify the management station when an exceptional condition occurs. that means fault, performance, and configuration information can keep piling up and get communicated to the management station conveniently and efficiently, even when the connection isn't continuous 🫶
- Proactive Monitoring 🔍: since the monitor has resources to spare, it's potentially helpful for it to keep running diagnostics and logging network performance 📊 the monitor is always available at the onset of any failure, so it can notify the management station and store historical statistical information about the failure 🧠 the management station can play that history back to dig deeper into the cause of the problem 🕵️♀️
- Problem Detection and Reporting 🚨: the monitor can be configured to recognize conditions, most notably error conditions, and keep checking for them. when one occurs, the event may be logged, and management stations may be notified in a number of ways 📣
- Value Added Data 👑: a remote monitoring device is a network resource dedicated exclusively to management functions, and it sits right on the monitored part of the network. that means it has the chance to add real value to the data it collects 🔥 for example, by highlighting the hosts that generate the most traffic or errors, the probe can hand the management station exactly the information it needs to solve a class of problems ✨
- Multiple Managers 🎀: an organization may have multiple management stations for different units, for different functions (like engineering and operations), and to provide disaster recovery. since environments with multiple management stations are common, the remote network monitoring device has to deal with more than its own management station, potentially using its resources concurrently 💅
2.2. Textual Conventions 🧁
two new data types are introduced as textual conventions in this MIB document. they make the spec easier to read and can make it easier to compare with other specifications when that's appropriate 🫧 just to be clear, introducing these textual conventions has no effect on either the syntax or the semantics of any managed objects. they're merely an artifact of the explanatory method. objects defined in terms of them are always encoded using the rules that define the primitive type, so no changes to the SMI or the SNMP are needed to accommodate them 🌸 they're adopted purely for the convenience of readers and writers chasing the elusive goal of clear, concise, and unambiguous MIB documents 🙌
the new data types are: OwnerString and EntryStatus 💜
2.3. Structure of MIB ✨
okay so the objects are sorted into these groups 🎀
- ethernet statistics
- history control
- ethernet history
- alarm
- host
- hostTopN
- matrix
- filter
- packet capture
- event
bestie, these groups are the basic unit of conformance 💅 like, if a remote monitoring device implements a group, it MUST implement all the objects in that group. For example, a managed agent that does the host group MUST do the hostControlTable, the hostTable and the hostTimeTable 🧚
all the groups in this MIB are OPTIONAL 🌸 but implementations of this MIB MUST also implement the system and interfaces group of MIB-II [6]. MIB-II might also require extra groups 🫶
the groups are defined so object identifiers can be assigned, and so managed agents know which objects they have to implement. literally that's the whole job 💖
2.3.1. The Ethernet Statistics Group 🦋
the ethernet statistics group holds the statistics the probe measures for each monitored Ethernet interface on the device. it's made of the etherStatsTable ✨ later on, other groups will be defined for other media types, including Token Ring and FDDI. those groups SHOULD follow the same model as the ethernet statistics group 🌈
2.3.2. The History Control Group 🍓
the history control group controls the periodic statistical sampling of data from different types of networks 🔥 it's made of the historyControlTable.
2.3.3. The Ethernet History Group 💜
the ethernet history group records periodic statistical samples from an ethernet network and stores them so you can pull them back up later 🙈 it's made of the etherHistoryTable. more groups for other media types, including Token Ring and FDDI, will come later 👑
2.3.4. The Alarm Group ⭐
the alarm group periodically takes statistical samples from variables in the probe and checks them against thresholds you configured earlier. if a monitored variable crosses a threshold, an event gets generated 💀 there's a hysteresis mechanism to limit how many alarms get generated 😭 this group is made of the alarmTable and REQUIRES the implementation of the event group 🎀
2.3.5. The Host Group 🌸
the host group holds statistics for each host discovered on the network 💅 it finds hosts by keeping a list of source and destination MAC Addresses seen in good packets promiscuously received from the network ✨ it's made of the hostControlTable, the hostTable, and the hostTimeTable 🫶
2.3.6. The HostTopN Group 👑
the hostTopN group prepares reports about the hosts that top a list ordered by one of their statistics 🔥 the statistics are samples of one of their base statistics over an interval the management station specifies, so they're rate based 💖 the management station also picks how many hosts get reported 🧚 this group is made of the hostTopNControlTable and the hostTopNTable, and it REQUIRES the implementation of the host group 🦋
2.3.7. The Matrix Group 🌈
the matrix group stores statistics for conversations between pairs of addresses 🍓 when the device detects a new conversation, it makes a new entry in its tables ✨ this group is made of the matrixControlTable, the matrixSDTable and the matrixDSTable 💅
2.3.8. The Filter Group 💜
the filter group lets packets get matched by a filter equation 🙈 the matched packets form a data stream that can be captured or can generate events ⭐ this group is made of the filterTable and the channelTable 🎀
2.3.9. The Packet Capture Group 🌸
the Packet Capture group lets packets get captured after they flow through a channel 💀 it's made of the bufferControlTable and the captureBufferTable, and it REQUIRES the implementation of the filter group 😭
2.3.10. The Event Group 👑
the event group controls the generation and notification of events from this device 🔥 it's made of the eventTable and the logTable 🫶
3. Control of Remote Network Monitoring Devices 🎀
these devices have a lot of complex functions, so they usually need user configuration 💖 often a function needs parameters set up for a data collection operation, and the operation can only proceed once those parameters are fully set up 🧚
lots of functional groups in this MIB have one or more tables for setting up control parameters, plus one or more data tables for the results 🦋 the control tables are typically read-write, while the data tables are typically read-only 🌈 since the parameters in a control table often describe the resulting data in the data table, lots of those parameters can only be modified when the control entry is invalid 🍓 so the way to change them is to invalidate the control entry, which deletes it along with any associated data entries, and then create a new control entry with the right parameters ✨ deleting the control entry is also a handy way to reclaim the resources used by the associated data 💅
some objects in this MIB can execute an action on the remote monitoring device 💜 those objects may execute an action because their state changed 🙈 for those objects in this MIB, a request to set an object to the value it already holds would cause no action to occur ⭐
to support control by multiple managers, resources have to be shared among the managers 🎀 these resources are typically the memory and computation resources a function needs 🌸
3.1. Resource Sharing Among Multiple Management Stations 💀
when multiple management stations want to use functions that compete for a limited amount of resources on a device, a way to share those resources is REQUIRED 😭 potential conflicts include:
- two management stations wanting to use resources at the same time that together would exceed what the device can handle 👑
- a management station using a big chunk of resources for a long time 🔥
- a management station using resources and then crashing, forgetting to free them so others can use them 🫶
this MIB provides a mechanism for each management station initiated function to avoid these conflicts and help resolve them when they happen 💖 each function has a label identifying its initiator (owner) 🧚 the initiator sets this label to allow for the following possibilities:
- a management station can recognize resources it owns and no longer needs 🦋
- a network operator can find the management station that owns a resource and negotiate for it to be freed 🌈
- a network operator may decide to unilaterally free resources another network operator has reserved 🍓
- when it initializes, a management station can recognize resources it reserved in the past ✨ with that info it can free them if it doesn't need them anymore 💅
management stations and probes SHOULD support any format of the owner string dictated by the local policy of the organization 💜 it's suggested that this name contain one or more of the following: IP address, management station name, network manager's name, location, or phone number 🙈 this info helps users share resources more effectively ⭐
there's often default functionality that the device or the probe's administrator (often the network administrator) wants to set up 🎀 the resources tied to that functionality are owned by the device itself or by the network administrator, and they're meant to be long-lived 🌸 in this case, the device or the administrator sets the relevant owner object to a string starting with 'monitor' 💀 indiscriminate modification of monitor-owned configuration by network management stations is discouraged 😭 in fact, a network management station SHOULD only modify these objects under the direction of the probe's administrator 👑
resources on a probe are scarce and are usually allocated when control rows are created by an application 🔥 since lots of applications may be using a probe at once, indiscriminate allocation of resources to particular applications is very likely to cause resource shortages in the probe 🫶
when a network management station wants to use a function in a monitor, it is encouraged to first scan that function's control table for an instance with similar parameters to share 💖 this is especially true for instances owned by the monitor, which can be assumed to change infrequently 🧚 if a management station decides to share an instance owned by another management station, it SHOULD understand that the owning management station may indiscriminately modify or delete it 🦋
it's worth noting that a management application should have the most trust in a monitor-owned row, because it should change very infrequently 🌈 a row owned by the management application is less long-lived, because a network administrator is more likely to reassign resources from a row in use by one user than from a monitor-owned row that's potentially in use by many users 🍓 a row owned by another application would be even less long-lived, because that application may delete or modify the row completely at its discretion 💅 ngl this part is so important for not stepping on each other's toes 🫶
3.2. Row Addition Among Multiple Management Stations ✨
Okay bestie, adding rows works the way [RFC 1212 [9]](#) describes 💅 Wait, let me say that properly: adding rows follows the method described in RFC 1212 [9]. In this MIB, rows often get added to a table to set up a function, and that setup usually comes with parameters that control how the function runs. The agent must check those parameters to make sure they're okay given the rules in this MIB and any implementation-specific limits, like not having enough resources 🙈 Implementors can get confused about when to check and when to tell the management station that something's invalid. There are two chances:
- When the management station sets each parameter object.
- When the management station sets the entry status object to valid.
If the latter is picked, the management station won't know which of the several parameters was invalid and caused the badValue error to be emitted 😭 So wherever possible, the implementor should pick the former, since it gives the management station more info 🎀
A problem can arise when multiple management stations try to set config info at the same time using SNMP 🌸 When that means adding a new conceptual row to the same control table, the managers might collide and try to create the same entry. To guard against this, each control entry has a status object with special semantics that help sort out the managers 👑 If an attempt is made with the row addition mechanism to create that status object and it already exists, an error is returned. When more than one manager tries to create the same conceptual row at once, only the first one succeeds. The others get an error.
When a manager wants to create a new control entry, it needs to choose an index for that row 🦋 It can pick the index in a variety of ways, hopefully minimizing the chances that the index is already in use by another manager. If it is in use, the mechanism above guards against collisions. Examples of schemes for choosing index values include random selection or scanning the control table for the first unused index. Because index values may be any valid value in the range and they're chosen by the manager, the agent must allow a row to be created with any unused index value if it has the resources to create a new row ✨
Some tables in this MIB reference other tables within this MIB. When creating or deleting entries in these tables, it's generally allowable for dangling references to exist. There's no defined order for creating or deleting entries in these tables 🧚
4. Conventions 📋
The following conventions are used throughout the RMON MIB and its companion documents. Literally everything in this next bit is what the whole RMON family is built on 💜
Good Packets
Good packets are error-free packets that have a valid frame length 🍓 For example, on Ethernet, good packets are error-free packets that are between 64 octets long and 1518 octets long. They follow the form defined in IEEE 802.3 section 3.2.all.
Bad Packets
Bad packets are packets that have proper framing and are therefore recognized as packets, but they contain errors within the packet or have an invalid length 💀 For example, on Ethernet, bad packets have a valid preamble and SFD, but have a bad CRC, or are either shorter than 64 octets or longer than 1518 octets.
5. Definitions 🎀
Here's the actual MIB module, the ASN.1 that the whole thing runs on 🔥
RMON-MIB DEFINITIONS ::= BEGIN
IMPORTS
Counter FROM RFC1155-SMI
DisplayString FROM RFC1158-MIB
mib-2 FROM RFC1213-MIB
OBJECT-TYPE FROM RFC-1212
TRAP-TYPE FROM RFC-1215;
-- Remote Network Monitoring MIB
rmon OBJECT IDENTIFIER ::= { mib-2 16 }
-- textual conventions
OwnerString ::= DisplayString
-- This data type is used to model an administratively
-- assigned name of the owner of a resource. This
-- information is taken from the NVT ASCII character
-- set. It is suggested that this name contain one or
-- more of the following: IP address, management station
-- name, network manager's name, location, or phone
-- number.
-- In some cases the agent itself will be the owner of
-- an entry. In these cases, this string shall be set
-- to a string starting with 'monitor'.
--
-- SNMP access control is articulated entirely in terms
-- of the contents of MIB views; access to a particular
-- SNMP object instance depends only upon its presence
-- or absence in a particular MIB view and never upon
-- its value or the value of related object instances.
-- Thus, objects of this type afford resolution of
-- resource contention only among cooperating managers;
-- they realize no access control function with respect
-- to uncooperative parties.
--
-- By convention, objects with this syntax are declared as
-- having
--
-- SIZE (0..127)
EntryStatus ::= INTEGER
{ valid(1),
createRequest(2),
underCreation(3),
invalid(4)
}
-- The status of a table entry.
--
-- Setting this object to the value invalid(4) has the
-- effect of invalidating the corresponding entry.
-- That is, it effectively disassociates the mapping
-- identified with said entry.
-- It is an implementation-specific matter as to whether
-- the agent removes an invalidated entry from the table.
-- Accordingly, management stations must be prepared to
-- receive tabular information from agents that
-- corresponds to entries currently not in use. Proper
-- interpretation of such entries requires examination
-- of the relevant EntryStatus object.
--
-- An existing instance of this object cannot be set to
-- createRequest(2). This object may only be set to
-- createRequest(2) when this instance is created. When
-- this object is created, the agent may wish to create
-- supplemental object instances with default values
-- to complete a conceptual row in this table. Because
-- the creation of these default objects is entirely at
-- the option of the agent, the manager must not assume
-- that any will be created, but may make use of any that
-- are created. Immediately after completing the create
-- operation, the agent must set this object to
-- underCreation(3).
--
-- When in the underCreation(3) state, an entry is
-- allowed to exist in a possibly incomplete, possibly
-- inconsistent state, usually to allow it to be
-- modified in mutiple PDUs. When in this state, an
-- entry is not fully active. Entries shall exist in
-- the underCreation(3) state until the management
-- station is finished configuring the entry and sets
-- this object to valid(1) or aborts, setting this
-- object to invalid(4). If the agent determines that
-- an entry has been in the underCreation(3) state for
-- an abnormally long time, it may decide that the
-- management station has crashed. If the agent makes
-- this decision, it may set this object to invalid(4)
-- to reclaim the entry. A prudent agent will
-- understand that the management station may need to
-- wait for human input and will allow for that
-- possibility in its determination of this abnormally
-- long period.
--
-- An entry in the valid(1) state is fully configured and
-- consistent and fully represents the configuration or
-- operation such a row is intended to represent. For
-- example, it could be a statistical function that is
-- configured and active, or a filter that is available
-- in the list of filters processed by the packet capture
-- process.
--
-- A manager is restricted to changing the state of an
-- entry in the following ways:
--
-- create under
-- To: valid Request Creation invalid
-- From:
-- valid OK NO OK OK
-- createRequest N/A N/A N/A N/A
-- underCreation OK NO OK OK
-- invalid NO NO NO OK
-- nonExistent NO OK NO OK
--
-- In the table above, it is not applicable to move the
-- state from the createRequest state to any other
-- state because the manager will never find the
-- variable in that state. The nonExistent state is
-- not a value of the enumeration, rather it means that
-- the entryStatus variable does not exist at all.
--
-- An agent may allow an entryStatus variable to change
-- state in additional ways, so long as the semantics
-- of the states are followed. This allowance is made
-- to ease the implementation of the agent and is made
-- despite the fact that managers should never
-- excercise these additional state transitions.
statistics OBJECT IDENTIFIER ::= { rmon 1 }
history OBJECT IDENTIFIER ::= { rmon 2 }
alarm OBJECT IDENTIFIER ::= { rmon 3 }
hosts OBJECT IDENTIFIER ::= { rmon 4 }
hostTopN OBJECT IDENTIFIER ::= { rmon 5 }
matrix OBJECT IDENTIFIER ::= { rmon 6 }
filter OBJECT IDENTIFIER ::= { rmon 7 }
capture OBJECT IDENTIFIER ::= { rmon 8 }
event OBJECT IDENTIFIER ::= { rmon 9 }
-- The Ethernet Statistics Group
--
-- Implementation of the Ethernet Statistics group is
-- optional.
--
-- The ethernet statistics group contains statistics
-- measured by the probe for each monitored interface on
-- this device. These statistics take the form of free
-- running counters that start from zero when a valid entry
-- is created.
--
-- This group currently has statistics defined only for
-- Ethernet interfaces. Each etherStatsEntry contains
-- statistics for one Ethernet interface. The probe must
-- create one etherStats entry for each monitored Ethernet
-- interface on the device.okay so this is where the etherStats table lives 💖 it's giving spreadsheet energy but make it networking. Every row is one Ethernet interface the probe is watching, and every counter in it is something the probe has been keeping track of. ✨
etherStatsTable OBJECT-TYPE
SYNTAX SEQUENCE OF EtherStatsEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A list of Ethernet statistics entries."
::= { statistics 1 }
etherStatsEntry OBJECT-TYPE
SYNTAX EtherStatsEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A collection of statistics kept for a particular
Ethernet interface. As an example, an instance of the
etherStatsPkts object might be named etherStatsPkts.1"
INDEX { etherStatsIndex }
::= { etherStatsTable 1 }
EtherStatsEntry ::= SEQUENCE {
etherStatsIndex INTEGER (1..65535),
etherStatsDataSource OBJECT IDENTIFIER,
etherStatsDropEvents Counter,
etherStatsOctets Counter,
etherStatsPkts Counter,
etherStatsBroadcastPkts Counter,
etherStatsMulticastPkts Counter,
etherStatsCRCAlignErrors Counter,
etherStatsUndersizePkts Counter,
etherStatsOversizePkts Counter,
etherStatsFragments Counter,
etherStatsJabbers Counter,
etherStatsCollisions Counter,
etherStatsPkts64Octets Counter,
etherStatsPkts65to127Octets Counter,
etherStatsPkts128to255Octets Counter,
etherStatsPkts256to511Octets Counter,
etherStatsPkts512to1023Octets Counter,
etherStatsPkts1024to1518Octets Counter,
etherStatsOwner OwnerString,
etherStatsStatus EntryStatus
}Each row gets its own index, and that's how you pick out a specific interface's stats. 🎀 The index is basically the row's ID card, so etherStatsIndex is the thing everyone uses to find the right entry. 🦋
etherStatsIndex OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The value of this object uniquely identifies this
etherStats entry."
::= { etherStatsEntry 1 }
etherStatsDataSource OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"This object identifies the source of the data that
this etherStats entry is configured to analyze. This
source can be any ethernet interface on this device.
In order to identify a particular interface, this
object shall identify the instance of the ifIndex
object, defined in RFC 1213 and RFC 1573 [4,6], for
the desired interface. For example, if an entry
were to receive data from interface #1, this object
would be set to ifIndex.1.
The statistics in this group reflect all packets
on the local network segment attached to the
identified interface.
An agent may or may not be able to tell if
fundamental changes to the media of the interface
have occurred and necessitate an invalidation of
this entry. For example, a hot-pluggable ethernet
card could be pulled out and replaced by a
token-ring card. In such a case, if the agent has
such knowledge of the change, it is recommended that
it invalidate this entry.
This object may not be modified if the associated
etherStatsStatus object is equal to valid(1)."
::= { etherStatsEntry 2 }The data source is where the probe is listening, and it's pointed at an interface through that interface's ifIndex 💅. The part about swapping a card out is kind of a plot twist: the agent might or might not notice that the media changed underneath it, and if it does notice, the guidance is to invalidate the entry 🙈. Also, once the entry is valid(1), this object is locked and can't be changed. Not me being dramatic about it, it's just the rule 😭
etherStatsDropEvents OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of events in which packets
were dropped by the probe due to lack of resources.
Note that this number is not necessarily the number of
packets dropped; it is just the number of times this
condition has been detected."
::= { etherStatsEntry 3 }
etherStatsOctets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of octets of data (including
those in bad packets) received on the
network (excluding framing bits but including
FCS octets).
This object can be used as a reasonable estimate of
ethernet utilization. If greater precision is
desired, the etherStatsPkts and etherStatsOctets
objects should be sampled before and after a common
interval. The differences in the sampled values are
Pkts and Octets, respectively, and the number of
seconds in the interval is Interval. These values
are used to calculate the Utilization as follows:
Pkts * (9.6 + 6.4) + (Octets * .8)
Utilization = -------------------------------------
Interval * 10,000
The result of this equation is the value Utilization
which is the percent utilization of the ethernet
segment on a scale of 0 to 100 percent."
::= { etherStatsEntry 4 }
etherStatsPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad packets,
broadcast packets, and multicast packets) received."
::= { etherStatsEntry 5 }
etherStatsBroadcastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of good packets received that were
directed to the broadcast address. Note that this
does not include multicast packets."
::= { etherStatsEntry 6 }
etherStatsMulticastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of good packets received that were
directed to a multicast address. Note that this
number does not include packets directed to the
broadcast address."
::= { etherStatsEntry 7 }Drop events are a count of moments, not packets 🌸 so one moment can cover a bunch of dropped packets, and the number doesn't tell you how many were actually lost. The octets counter is the one people use to estimate how busy the wire is ✨. There's a whole formula for it, with Pkts, Octets, and Interval, and it spits out a percentage from 0 to 100 🔥. For more precision you sample the counters before and after the same interval, which is very much a math-girl move 🧚
Packets are counted two ways here: etherStatsPkts counts everything, bad ones included, while the broadcast and multicast counters only count the good ones 💀. Also note that broadcast and multicast don't overlap, since each one explicitly leaves out the other 🍓
etherStatsCRCAlignErrors OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets received that
had a length (excluding framing bits, but
including FCS octets) of between 64 and 1518
octets, inclusive, but but had either a bad
Frame Check Sequence (FCS) with an integral
number of octets (FCS Error) or a bad FCS with
a non-integral number of octets (Alignment Error)."
::= { etherStatsEntry 8 }
etherStatsUndersizePkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets received that were
less than 64 octets long (excluding framing bits,
but including FCS octets) and were otherwise well
formed."
::= { etherStatsEntry 9 }
etherStatsOversizePkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets received that were
longer than 1518 octets (excluding framing bits,
but including FCS octets) and were otherwise
well formed."
::= { etherStatsEntry 10 }
etherStatsFragments OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets received that were less
than 64 octets in length (excluding framing bits but
including FCS octets) and had either a bad Frame
Check Sequence (FCS) with an integral number of
octets (FCS Error) or a bad FCS with a non-integral
number of octets (Alignment Error).
Note that it is entirely normal for
etherStatsFragments to increment. This is because
it counts both runts (which are normal occurrences
due to collisions) and noise hits."
::= { etherStatsEntry 11 }
etherStatsJabbers OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets received that were
longer than 1518 octets (excluding framing bits,
but including FCS octets), and had either a bad
Frame Check Sequence (FCS) with an integral number
of octets (FCS Error) or a bad FCS with a
non-integral number of octets (Alignment Error).
Note that this definition of jabber is different
than the definition in IEEE-802.3 section 8.2.1.5
(10BASE5) and section 10.3.1.4 (10BASE2). These
documents define jabber as the condition where any
packet exceeds 20 ms. The allowed range to detect
jabber is between 20 ms and 150 ms."
::= { etherStatsEntry 12 }The CRC and alignment errors are the "this frame is damaged" bucket 💔, and they only count frames that land between 64 and 1518 octets. Undersize and oversize are the "wrong length but otherwise fine" buckets 🙈. Fragments are the tiny damaged ones, and the spec is honest that it's totally normal for that number to climb, since it catches both runts from collisions and noise hits 🦋
Jabbers get a special mention because this definition is NOT the same as the IEEE-802.3 one 😭. The standard calls jabber anything over 20 ms, but this object says the valid detection window is somewhere between 20 ms and 150 ms. Different vibes, so don't mix them up 🙅♀️
etherStatsCollisions OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The best estimate of the total number of collisions
on this Ethernet segment.
The value returned will depend on the location of
the RMON probe. Section 8.2.1.3 (10BASE-5) and
section 10.3.1.3 (10BASE-2) of IEEE standard 802.3
states that a station must detect a collision, in
the receive mode, if three or more stations are
transmitting simultaneously. A repeater port must
detect a collision when two or more stations are
transmitting simultaneously. Thus a probe placed on
a repeater port could record more collisions than a
probe connected to a station on the same segment
would.
Probe location plays a much smaller role when
considering 10BASE-T. 14.2.1.4 (10BASE-T) of IEEE
standard 802.3 defines a collision as the
simultaneous presence of signals on the DO and RD
circuits (transmitting and receiving at the same
time). A 10BASE-T station can only detect
collisions when it is transmitting. Thus probes
placed on a station and a repeater, should report
the same number of collisions.Collisions are the last one and honestly the most location-dependent 🌈. The spec says it's a "best estimate", because where your probe sits changes what it can see. On 10BASE-5 and 10BASE-2, a repeater port can catch collisions that a station on the same segment would miss 👑. On 10BASE-T, though, probe location barely matters, and a probe on a station and a probe on a repeater should report the same number 🫶
okay so we're still in the etherStats table, and the first thing up is the tail of the collisions description 💖
Note also that an RMON probe inside a repeater
should ideally report collisions between the
repeater and one or more other hosts (transmit
collisions as defined by IEEE 802.3k) plus receiver
collisions observed on any coax segments to which
the repeater is connected."
::= { etherStatsEntry 13 }
etherStatsPkts64Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were 64 octets in length
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 14 }
etherStatsPkts65to127Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were between
65 and 127 octets in length inclusive
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 15 }
etherStatsPkts128to255Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were between
128 and 255 octets in length inclusive
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 16 }
etherStatsPkts256to511Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were between
256 and 511 octets in length inclusive
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 17 }
etherStatsPkts512to1023Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were between
512 and 1023 octets in length inclusive
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 18 }
etherStatsPkts1024to1518Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were between
1024 and 1518 octets in length inclusive
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 19 }
etherStatsOwner OBJECT-TYPE
SYNTAX OwnerString
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The entity that configured this entry and is
therefore using the resources assigned to it."
::= { etherStatsEntry 20 }
etherStatsStatus OBJECT-TYPE
SYNTAX EntryStatus
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The status of this etherStats entry."
::= { etherStatsEntry 21 }
-- The History Control Group
-- Implementation of the History Control group is optional.
--
-- The history control group controls the periodic statistical
-- sampling of data from various types of networks. The
-- historyControlTable stores configuration entries that each
-- define an interface, polling period, and other parameters.
-- Once samples are taken, their data is stored in an entry
-- in a media-specific table. Each such entry defines one
-- sample, and is associated with the historyControlEntry that
-- caused the sample to be taken. Each counter in the
-- etherHistoryEntry counts the same event as its
-- similarly-named counterpart in the etherStatsEntry,
-- except that each value here is a cumulative sum during a
-- sampling period.
--
-- If the probe keeps track of the time of day, it should
-- start the first sample of the history at a time such that
-- when the next hour of the day begins, a sample is
-- started at that instant. This tends to make more
-- user-friendly reports, and enables comparison of reports
-- from different probes that have relatively accurate time
-- of day.
--
-- The probe is encouraged to add two history control entries
-- per monitored interface upon initialization that describe
-- a short term and a long term polling period. Suggested
-- parameters are 30 seconds for the short term polling period
-- and 30 minutes for the long term period.
historyControlTable OBJECT-TYPE
SYNTAX SEQUENCE OF HistoryControlEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A list of history control entries."
::= { history 1 }
historyControlEntry OBJECT-TYPE
SYNTAX HistoryControlEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A list of parameters that set up a periodic sampling
of statistics. As an example, an instance of the
historyControlInterval object might be named
historyControlInterval.2"
INDEX { historyControlIndex }
::= { historyControlTable 1 }
HistoryControlEntry ::= SEQUENCE {
historyControlIndex INTEGER (1..65535),
historyControlDataSource OBJECT IDENTIFIER,
historyControlBucketsRequested INTEGER (1..65535),
historyControlBucketsGranted INTEGER (1..65535),
historyControlInterval INTEGER (1..3600),
historyControlOwner OwnerString,
historyControlStatus EntryStatus
}
historyControlIndex OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"An index that uniquely identifies an entry in the
historyControl table. Each such entry defines a
set of samples at a particular interval for an
interface on the device."
::= { historyControlEntry 1 }
historyControlDataSource OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"This object identifies the source of the data for
which historical data was collected and
placed in a media-specific table on behalf of this
historyControlEntry. This source can be any
interface on this device. In order to identify
a particular interface, this object shall identify
the instance of the ifIndex object, defined
in RFC 1213 and RFC 1573 [4,6], for the desired
interface. For example, if an entry were to receive
data from interface #1, this object would be set
to ifIndex.1.
The statistics in this group reflect all packets
on the local network segment attached to the
identified interface.
An agent may or may not be able to tell if fundamental
changes to the media of the interface have occurred
and necessitate an invalidation of this entry. For
example, a hot-pluggable ethernet card could be
pulled out and replaced by a token-ring card. In
such a case, if the agent has such knowledge of the
change, it is recommended that it invalidate this
entry.
This object may not be modified if the associated
historyControlStatus object is equal to valid(1)."
::= { historyControlEntry 2 }
historyControlBucketsRequested OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The requested number of discrete time intervals
over which data is to be saved in the part of the
media-specific table associated with this
historyControlEntry.
When this object is created or modified, the probe
should set historyControlBucketsGranted as closely to
this object as is possible for the particular probe
implementation and available resources."
DEFVAL { 50 }
::= { historyControlEntry 3 }
historyControlBucketsGranted OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of discrete sampling intervals
over which data shall be saved in the part of
the media-specific table associated with this
historyControlEntry.
When the associated historyControlBucketsRequested
object is created or modified, the probe
should set this object as closely to the requested
value as is possible for the particular
probe implementation and available resources. The
probe must not lower this value except as a result
of a modification to the associated
historyControlBucketsRequested object.
There will be times when the actual number of
buckets associated with this entry is less than
the value of this object. In this case, at the
end of each sampling interval, a new bucket will
be added to the media-specific table.
When the number of buckets reaches the value of
this object and a new bucket is to be added to the
media-specific table, the oldest bucket associated
with this historyControlEntry shall be deleted by
the agent so that the new bucket can be added.
When the value of this object changes to a value less
than the current value, entries are deleted
from the media-specific table associated with this
historyControlEntry. Enough of the oldest of these
entries shall be deleted by the agent so that their
number remains less than or equal to the new value of
this object.
When the value of this object changes to a value
greater than the current value, the number of
associated media- specific entries may be allowed to
grow."
::= { historyControlEntry 4 }Okay so the big one first: historyControlInterval 💖 This is how many seconds each sample bucket covers, and it has to be somewhere between 1 and 3600 (that's one whole hour, bestie 🕐). It's read-write, and the default is 1800 ✨
historyControlInterval OBJECT-TYPE
SYNTAX INTEGER (1..3600)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The interval in seconds over which the data is
sampled for each bucket in the part of the
media-specific table associated with this
historyControlEntry. This interval can
be set to any number of seconds between 1 and
3600 (1 hour).
Because the counters in a bucket may overflow at their
maximum value with no indication, a prudent manager
will take into account the possibility of overflow
in any of the associated counters. It is important
to consider the minimum time in which any counter
could overflow on a particular media type and set
the historyControlInterval object to a value less
than this interval. This is typically most
important for the 'octets' counter in any
media-specific table. For example, on an Ethernet
network, the etherHistoryOctets counter could
overflow in about one hour at the Ethernet's maximum
utilization.
This object may not be modified if the associated
historyControlStatus object is equal to valid(1)."
DEFVAL { 1800 }
::= { historyControlEntry 5 }Now the overflow part is the tea 🫖 Counters can wrap at their max with zero warning, so a smart manager has to plan for it 😭 You want the interval set to something shorter than the time a counter could overflow on that media type. The octets counter is the main one to watch, and on Ethernet, etherHistoryOctets could roll over in about an hour at max utilization. Literally scary stuff 💀
Also, this object is locked once historyControlStatus is valid(1), so you can't change it on a live entry 🔒
historyControlOwner OBJECT-TYPE
SYNTAX OwnerString
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The entity that configured this entry and is
therefore using the resources assigned to it."
::= { historyControlEntry 6 }
historyControlStatus OBJECT-TYPE
SYNTAX EntryStatus
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The status of this historyControl entry.
Each instance of the media-specific table associated
with this historyControlEntry will be deleted by the
agent if this historyControlEntry is not equal to
valid(1)."
::= { historyControlEntry 7 }historyControlOwner is basically "who set this up and is using the resources" 🎀 And historyControlStatus is the vibe check for the whole entry 🧚 If it isn't valid(1), the agent deletes every media-specific table instance tied to it. No cap, that's a whole cleanup 🧹
Next up is the Ethernet History Group 🌸 Implementing it is optional, and the idea is simple: it grabs periodic stats from a network and saves them so you can pull them back out later. Each saved sample lives in a media-specific table, and each one is linked back to the historyControlEntry that kicked off the sampling. For Ethernet, that table is etherHistoryTable.
-- The Ethernet History Group
-- Implementation of the Ethernet History group is optional.
--
-- The Ethernet History group records periodic
-- statistical samples from a network and stores them
-- for later retrieval. Once samples are taken, their
-- data is stored in an entry in a media-specific
-- table. Each such entry defines one sample, and is
-- associated with the historyControlEntry that caused
-- the sample to be taken. This group defines the
-- etherHistoryTable, for Ethernet networks.
--
etherHistoryTable OBJECT-TYPE
SYNTAX SEQUENCE OF EtherHistoryEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A list of Ethernet history entries."
::= { history 2 }
etherHistoryEntry OBJECT-TYPE
SYNTAX EtherHistoryEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"An historical sample of Ethernet statistics on a
particular Ethernet interface. This sample is
associated with the historyControlEntry which set up
the parameters for a regular collection of these
samples. As an example, an instance of the
etherHistoryPkts object might be named
etherHistoryPkts.2.89"
INDEX { etherHistoryIndex , etherHistorySampleIndex }
::= { etherHistoryTable 1 }
EtherHistoryEntry ::= SEQUENCE {
etherHistoryIndex INTEGER (1..65535),
etherHistorySampleIndex INTEGER (1..2147483647),
etherHistoryIntervalStart TimeTicks,
etherHistoryDropEvents Counter,
etherHistoryOctets Counter,
etherHistoryPkts Counter,
etherHistoryBroadcastPkts Counter,
etherHistoryMulticastPkts Counter,
etherHistoryCRCAlignErrors Counter,
etherHistoryUndersizePkts Counter,
etherHistoryOversizePkts Counter,
etherHistoryFragments Counter,
etherHistoryJabbers Counter,
etherHistoryCollisions Counter,
etherHistoryUtilization INTEGER (0..10000)
}So each row in etherHistoryTable is one sample 🦋 It's indexed by etherHistoryIndex plus etherHistorySampleIndex, and the example in the description is etherHistoryPkts.2.89, which is giving very specific main character energy 💅
Now the index objects 🔑 etherHistoryIndex tells you which history the sample belongs to, and it matches the same value as historyControlIndex. etherHistorySampleIndex is the sample's own number. It starts at 1 and goes up by one every time a new sample gets taken 🔢
etherHistoryIndex OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The history of which this entry is a part. The
history identified by a particular value of this
index is the same history as identified
by the same value of historyControlIndex."
::= { etherHistoryEntry 1 }
etherHistorySampleIndex OBJECT-TYPE
SYNTAX INTEGER (1..2147483647)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"An index that uniquely identifies the particular
sample this entry represents among all samples
associated with the same historyControlEntry.
This index starts at 1 and increases by one
as each new sample is taken."
::= { etherHistoryEntry 2 }The timing one is cute ⏰ etherHistoryIntervalStart is the sysUpTime at the start of the sample's interval. If the probe knows the time of day, it's supposed to line up the first sample so a new sample begins right when the next hour starts 🕐 That might mean waiting a bit before the first sample, since every sample has to be the same length. And the sample currently being collected can't be read from this table until its interval ends, so no peeking mid-sample 🙈
etherHistoryIntervalStart OBJECT-TYPE
SYNTAX TimeTicks
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The value of sysUpTime at the start of the interval
over which this sample was measured. If the probe
keeps track of the time of day, it should start
the first sample of the history at a time such that
when the next hour of the day begins, a sample is
started at that instant. Note that following this
rule may require the probe to delay collecting the
first sample of the history, as each sample must be
of the same interval. Also note that the sample which
is currently being collected is not accessible in this
table until the end of its interval."
::= { etherHistoryEntry 3 }Now the counters 🧮 etherHistoryDropEvents counts how many times packets got dropped because the probe ran out of resources during that sample. Quick heads up though: it's counting events, not the number of packets dropped 👀
etherHistoryDropEvents OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of events in which packets
were dropped by the probe due to lack of resources
during this sampling interval. Note that this number
is not necessarily the number of packets dropped, it
is just the number of times this condition has been
detected."
::= { etherHistoryEntry 4 }
etherHistoryOctets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of octets of data (including
those in bad packets) received on the
network (excluding framing bits but including
FCS octets)."
::= { etherHistoryEntry 5 }
etherHistoryPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of packets (including bad packets)
received during this sampling interval."
::= { etherHistoryEntry 6 }
etherHistoryBroadcastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of good packets received during this
sampling interval that were directed to the
broadcast address."
::= { etherHistoryEntry 7 }
etherHistoryMulticastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of good packets received during this
sampling interval that were directed to a
multicast address. Note that this number does not
include packets addressed to the broadcast address."
::= { etherHistoryEntry 8 }So etherHistoryOctets is every octet received, bad packets included, minus framing bits but keeping FCS octets 🧃 etherHistoryPkts is the same deal, counting bad packets too 📦 Broadcast only counts good packets sent to the broadcast address 📢 And multicast is the good-packet count for multicast addresses, but broadcast doesn't get double-counted in it 🙅♀️
Next up are the error counters, and they're kinda messy 😭 etherHistoryCRCAlignErrors covers packets between 64 and 1518 octets (inclusive) that have a bad FCS, whether it's an FCS Error or an Alignment Error. etherHistoryUndersizePkts is packets under 64 octets that are otherwise well formed, and etherHistoryOversizePkts is packets over 1518 octets that are otherwise well formed 🥲
etherHistoryCRCAlignErrors OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of packets received during this sampling
interval that had a length (excluding framing bits
but including FCS octets) between 64 and 1518
octets, inclusive, but had either a bad Frame Check
Sequence (FCS) with an integral number of octets
(FCS Error) or a bad FCS with a non-integral number
of octets (Alignment Error)."
::= { etherHistoryEntry 9 }
etherHistoryUndersizePkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of packets received during this
sampling interval that were less than 64 octets
long (excluding framing bits but including FCS
octets) and were otherwise well formed."
::= { etherHistoryEntry 10 }
etherHistoryOversizePkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of packets received during this
sampling interval that were longer than 1518
octets (excluding framing bits but including
FCS octets) but were otherwise well formed."
::= { etherHistoryEntry 11 }etherHistoryFragments is the one with the big "it's normal, don't panic" note 🫶 It counts packets under 64 octets that have a bad FCS (FCS Error or Alignment Error), and the spec says it's totally normal for it to go up, because it picks up both runts from collisions and noise hits 🌧️
etherHistoryFragments OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets received during this
sampling interval that were less than 64 octets in
length (excluding framing bits but including FCS octets)
had either a bad Frame Check Sequence (FCS)
with an integral number of octets (FCS Error) or a bad
FCS with a non-integral number of octets (Alignment
Error).
Note that it is entirely normal for
etherHistoryFragments to increment. This is because
it counts both runts (which are normal occurrences
due to collisions) and noise hits."
::= { etherHistoryEntry 12 }
etherHistoryJabbers OBJECT-TYPE
<pink>okay the ethernet history stats are wrapping up</pink> 💅 <lavender>then we're officially in alarm territory</lavender> 🚨
SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of packets received during this sampling interval that were longer than 1518 octets (excluding framing bits but including FCS octets), and had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a non-integral number of octets (Alignment Error).
Note that this definition of jabber is different than the definition in IEEE-802.3 section 8.2.1.5 (10BASE5) and section 10.3.1.4 (10BASE2). These documents define jabber as the condition where any packet exceeds 20 ms. The allowed range to detect jabber is between 20 ms and 150 ms." ::= { etherHistoryEntry 13 }
etherHistoryCollisions OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The best estimate of the total number of collisions on this Ethernet segment during this sampling interval.
The value returned will depend on the location of the RMON probe. Section 8.2.1.3 (10BASE-5) and section 10.3.1.3 (10BASE-2) of IEEE standard 802.3 states that a station must detect a collision, in the receive mode, if three or more stations are transmitting simultaneously. A repeater port must detect a collision when two or more stations are transmitting simultaneously. Thus a probe placed on a repeater port could record more collisions than a probe connected to a station on the same segment would.
Probe location plays a much smaller role when considering 10BASE-T. 14.2.1.4 (10BASE-T) of IEEE standard 802.3 defines a collision as the simultaneous presence of signals on the DO and RD circuits (transmitting and receiving at the same time). A 10BASE-T station can only detect collisions when it is transmitting. Thus probes placed on a station and a repeater, should report the same number of collisions.
Note also that an RMON probe inside a repeater should ideally report collisions between the repeater and one or more other hosts (transmit collisions as defined by IEEE 802.3k) plus receiver collisions observed on any coax segments to which the repeater is connected." ::= { etherHistoryEntry 14 }
etherHistoryUtilization OBJECT-TYPE SYNTAX INTEGER (0..10000) ACCESS read-only STATUS mandatory DESCRIPTION "The best estimate of the mean physical layer network utilization on this interface during this sampling interval, in hundredths of a percent." ::= { etherHistoryEntry 15 }
-- The Alarm Group
-- Implementation of the Alarm group is optional. -- -- The Alarm Group requires the implementation of the Event -- group. -- -- The Alarm group periodically takes -- statistical samples from variables in the probe 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 (INTEGER, Counter, Gauge, or -- TimeTicks) 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 a sampling a deltaValue, a probe 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 probes -- implement this more precise algorithm.
alarmTable OBJECT-TYPE SYNTAX SEQUENCE OF AlarmEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of alarm entries." ::= { alarm 1 }
alarmEntry OBJECT-TYPE SYNTAX AlarmEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of parameters that set up a periodic checking for alarm conditions. For example, an instance of the alarmValue object might be named alarmValue.8" INDEX { alarmIndex } ::= { alarmTable 1 }
AlarmEntry ::= SEQUENCE { alarmIndex INTEGER (1..65535), alarmInterval INTEGER, alarmVariable OBJECT IDENTIFIER, alarmSampleType INTEGER, alarmValue INTEGER, alarmStartupAlarm INTEGER, alarmRisingThreshold INTEGER, alarmFallingThreshold INTEGER, alarmRisingEventIndex INTEGER (0..65535), alarmFallingEventIndex INTEGER (0..65535), alarmOwner OwnerString, alarmStatus EntryStatus }
alarmIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION
"An index that uniquely identifies an entry in the alarm table. Each such entry defines a diagnostic sample at a particular interval for an object on the device." ::= { alarmEntry 1 }
alarmInterval OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION "The interval in seconds over which the data is sampled and compared with the rising and falling thresholds. When setting this variable, care should be taken in the case of deltaValue sampling - the interval should be set short enough that the sampled variable is very unlikely to increase or decrease by more than 2^31 - 1 during a single sampling interval.
This object may not be modified if the associated alarmStatus object is equal to valid(1)." ::= { alarmEntry 2 }
alarmVariable OBJECT-TYPE SYNTAX OBJECT IDENTIFIER ACCESS read-write STATUS mandatory DESCRIPTION "The object identifier of the particular variable to be sampled. Only variables that resolve to an ASN.1 primitive type of INTEGER (INTEGER, Counter, Gauge, or TimeTicks) may be sampled.
Because SNMP access control is articulated entirely in terms of the contents of MIB views, no access control mechanism exists that can restrict the value of this object to identify only those objects that exist in a particular MIB view. Because there is thus no acceptable means of restricting the read access that could be obtained through the alarm mechanism, the probe must only grant write access to this object in those views that have read access to all objects on the probe.
During a set operation, if the supplied variable name is not available in the selected MIB view, a badValue error must be returned. If at any time the variable name of an established alarmEntry is no longer available in the selected MIB view, the probe must change the status of this alarmEntry to invalid(4).
This object may not be modified if the associated alarmStatus object is equal to valid(1)." ::= { alarmEntry 3 }
alarmSampleType OBJECT-TYPE SYNTAX INTEGER { absoluteValue(1), deltaValue(2) } ACCESS read-write STATUS mandatory 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(1), the value of the selected variable will be compared directly with the thresholds at the end of the sampling interval. If the value of this object is deltaValue(2), the value of the selected variable at the last sample will be subtracted from the current value, and the difference compared with the thresholds.
This object may not be modified if the associated alarmStatus object is equal to valid(1)." ::= { alarmEntry 4 }
alarmValue OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "The value of the statistic during the last sampling period. For example, if the sample type is deltaValue, this value will be the difference between the samples at the beginning and end of the period. If the sample type is absoluteValue, this value will be the sampled value at the end of the period.
This is the value that is compared with the rising and falling thresholds.
The value during the current sampling period is not made available until the period is completed and will remain available until the next period completes." ::= { alarmEntry 5 }
okay the alarm stuff is giving *startup drama* 😭 these are the settings that decide what fires the very first time an entry goes valid 🎀
alarmStartupAlarm OBJECT-TYPE SYNTAX INTEGER { risingAlarm(1), fallingAlarm(2), risingOrFallingAlarm(3) } ACCESS read-write STATUS mandatory DESCRIPTION "The alarm that may be sent when this entry is first set to valid. If the first sample after this entry becomes valid is greater than or equal to the risingThreshold and alarmStartupAlarm is equal to risingAlarm(1) or risingOrFallingAlarm(3), then a single rising alarm will be generated. If the first sample after this entry becomes valid is less than or equal to the fallingThreshold and alarmStartupAlarm is equal to fallingAlarm(2) or risingOrFallingAlarm(3), then a single falling alarm will be generated.
This object may not be modified if the associated alarmStatus object is equal to valid(1)." ::= { alarmEntry 6 }
alarmRisingThreshold OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory 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 valid is greater than or equal to this threshold and the associated alarmStartupAlarm is equal to risingAlarm(1) or risingOrFallingAlarm(3).
After a rising event is generated, another such event will not be generated until the sampled value falls below this threshold and reaches the alarmFallingThreshold.
This object may not be modified if the associated alarmStatus object is equal to valid(1)." ::= { alarmEntry 7 }
alarmFallingThreshold OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory 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 valid is less than or equal to this threshold and the associated alarmStartupAlarm is equal to fallingAlarm(2) or risingOrFallingAlarm(3).
After a falling event is generated, another such event will not be generated until the sampled value rises above this threshold and reaches the alarmRisingThreshold.
This object may not be modified if the associated alarmStatus object is equal to valid(1)." ::= { alarmEntry 8 }
alarmRisingEventIndex OBJECT-TYPE SYNTAX INTEGER (0..65535) ACCESS read-write STATUS mandatory DESCRIPTION "The index of the eventEntry that is used when a rising threshold is crossed. The eventEntry identified by a particular value of this index is the same as identified by the same value of the eventIndex object. If there is no corresponding entry in the eventTable, then no association exists. In particular, if this value is zero, no associated event will be generated, as zero is not a valid event index.
This object may not be modified if the associated alarmStatus object is equal to valid(1)." ::= { alarmEntry 9 }
alarmFallingEventIndex OBJECT-TYPE SYNTAX INTEGER (0..65535) ACCESS read-write STATUS mandatory DESCRIPTION "The index of the eventEntry that is used when a falling threshold is crossed. The eventEntry identified by a particular value of this index is the same as identified by the same value of the eventIndex object. If there is no corresponding entry in the eventTable, then no association exists. In particular, if this value is zero, no associated event will be generated, as zero is not a valid event index.
This object may not be modified if the associated alarmStatus object is equal to valid(1)." ::= { alarmEntry 10 }
alarmOwner OBJECT-TYPE SYNTAX OwnerString ACCESS read-write STATUS mandatory DESCRIPTION "The entity that configured this entry and is therefore using the resources assigned to it." ::= { alarmEntry 11 }
alarmStatus OBJECT-TYPE SYNTAX EntryStatus ACCESS read-write STATUS mandatory DESCRIPTION "The status of this alarm entry." ::= { alarmEntry 12 }
ok the Host Group is next and it's a whole vibe 🦋 it's all about discovering hosts and keeping their stats, and there's a table that's basically a *creation-order situationship* 💀 read the comments, they're the tea
-- The Host Group
-- Implementation of the Host group is optional. -- -- The host group discovers new hosts on the network by -- keeping a list of source and destination MAC Addresses seen -- in good packets. For each of these addresses, the host -- group keeps a set of statistics. The hostControlTable -- controls which interfaces this function is performed on, -- and contains some information about the process. On -- behalf of each hostControlEntry, data is collected on an -- interface and placed in both the hostTable and the -- hostTimeTable. If the monitoring device finds itself -- short of resources, it may delete entries as needed. It -- is suggested that the device delete the least recently -- used entries first.
-- The hostTable contains entries for each address -- discovered on a particular interface. Each entry -- contains statistical data about that host. This table is -- indexed by the MAC address of the host, through which a -- random access may be achieved.
-- The hostTimeTable contains data in the same format as the -- hostTable, and must contain the same set of hosts, but is -- indexed using hostTimeCreationOrder rather than -- hostAddress. -- The hostTimeCreationOrder is an integer which reflects -- the relative order in which a particular entry was -- discovered and thus inserted into the table. As this -- order, and thus the index, is among those entries -- currently in the table, the index for a particular entry -- may change if an (earlier) entry is deleted. Thus the -- association between hostTimeCreationOrder and -- hostTimeEntry may be broken at any time.
-- The hostTimeTable has two important uses. The first is the -- fast download of this potentially large table. Because the -- index of this table runs from 1 to the size of the table, -- inclusive, its values are predictable. This allows very -- efficient packing of variables into SNMP PDU's and allows -- a table transfer to have multiple packets outstanding. -- These benefits increase transfer rates tremendously.
-- The second use of the hostTimeTable is the efficient -- discovery by the management station of new entries added -- to the table. After the management station has downloaded -- the entire table, it knows that new entries will be added -- immediately after the end of the current table. It can -- thus detect new entries there and retrieve them easily.
-- Because the association between hostTimeCreationOrder and -- hostTimeEntry may be broken at any time, the management -- station must monitor the related hostControlLastDeleteTime -- object. When the management station thus detects a -- deletion, it must assume that any such associations have --- been broken, and invalidate any it has stored locally. -- This includes restarting any download of the -- hostTimeTable that may have been in progress, as well as -- rediscovering the end of the hostTimeTable so that it may -- detect new entries. If the management station does not -- detect the broken association, it may continue to refer -- to a particular host by its creationOrder while -- unwittingly retrieving the data associated with another -- host entirely. If this happens while downloading the -- host table, the management station may fail to download -- all of the entries in the table.
hostControlTable OBJECT-TYPE SYNTAX SEQUENCE OF HostControlEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of host table control entries." ::= { hosts 1 }
hostControlEntry OBJECT-TYPE SYNTAX HostControlEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of parameters that set up the discovery of hosts on a particular interface and the collection of statistics about these hosts. For example, an instance of the hostControlTableSize object might be named hostControlTableSize.1" INDEX { hostControlIndex } ::= { hostControlTable 1 }
HostControlEntry ::= SEQUENCE { hostControlIndex INTEGER (1..65535), hostControlDataSource OBJECT IDENTIFIER, hostControlTableSize INTEGER, hostControlLastDeleteTime TimeTicks, hostControlOwner OwnerString, hostControlStatus EntryStatus }
hostControlIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "An index that uniquely identifies an entry in the hostControl table. Each such entry defines a function that discovers hosts on a particular interface and places statistics about them in the hostTable and the hostTimeTable on behalf of this hostControlEntry." ::= { hostControlEntry 1 }
Okay bestie, the **hostControl** entry is basically the setup page for the whole Host Group 💅 It says where the data comes from, how many hosts it's tracking, when the last deletion happened, who owns it, and whether it's switched on. Let's get into it 🫶
hostControlDataSource OBJECT-TYPE SYNTAX OBJECT IDENTIFIER ACCESS read-write STATUS mandatory DESCRIPTION "This object identifies the source of the data for this instance of the host function. This source can be any interface on this device. In order to identify a particular interface, this object shall identify the instance of the ifIndex object, defined in RFC 1213 and RFC 1573 [4,6], for the desired interface. For example, if an entry were to receive data from interface #1, this object would be set to ifIndex.1.
The statistics in this group reflect all packets on the local network segment attached to the identified interface.
An agent may or may not be able to tell if fundamental changes to the media of the interface have occurred and necessitate an invalidation of this entry. For example, a hot-pluggable ethernet card could be pulled out and replaced by a token-ring card. In such a case, if the agent has such knowledge of the change, it is recommended that it invalidate this entry.
This object may not be modified if the associated hostControlStatus object is equal to valid(1)." ::= { hostControlEntry 2 }
So **hostControlDataSource** is the interface you're pulling data from 🔌 You point it at an `ifIndex` instance (like `ifIndex.1` for interface #1), and the stats cover everything on that local network segment 🌸 If the card gets swapped out for a totally different type, the agent might want to kill the entry, but only if it actually knows the media changed 👀 And once the entry is **valid(1)**, you can't touch this field anymore 🔒
hostControlTableSize OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "The number of hostEntries in the hostTable and the hostTimeTable associated with this hostControlEntry." ::= { hostControlEntry 3 }
hostControlLastDeleteTime OBJECT-TYPE SYNTAX TimeTicks ACCESS read-only STATUS mandatory DESCRIPTION "The value of sysUpTime when the last entry was deleted from the portion of the hostTable associated with this hostControlEntry. If no deletions have occurred, this value shall be zero." ::= { hostControlEntry 4 }
hostControlOwner OBJECT-TYPE SYNTAX OwnerString ACCESS read-write STATUS mandatory DESCRIPTION "The entity that configured this entry and is therefore using the resources assigned to it." ::= { hostControlEntry 5 }
hostControlStatus OBJECT-TYPE SYNTAX EntryStatus ACCESS read-write STATUS mandatory DESCRIPTION "The status of this hostControl entry.
If this object is not equal to valid(1), all associated entries in the hostTable, hostTimeTable, and the hostTopNTable shall be deleted by the agent." ::= { hostControlEntry 6 }
<mint>**hostControlTableSize**</mint> is the head count 🧮 It's how many host entries are sitting in the **hostTable** and **hostTimeTable** for this control entry. <lavender>**hostControlLastDeleteTime**</lavender> is the "when did someone last get dropped?" timestamp ⏰ It's a `sysUpTime` value, and if nothing's ever been deleted, it stays at zero 🫠 <pink>**hostControlOwner**</pink> is the entity that set the whole thing up and is using those resources 💖
And **hostControlStatus** is the on/off switch with main character energy 👑 If it isn't **valid(1)**, the agent has to wipe out every related entry in the **hostTable**, **hostTimeTable**, and **hostTopNTable**. Not a vibe, a requirement 💀
---
hostTable OBJECT-TYPE SYNTAX SEQUENCE OF HostEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of host entries." ::= { hosts 2 }
hostEntry OBJECT-TYPE SYNTAX HostEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A collection of statistics for a particular host that has been discovered on an interface of this device. For example, an instance of the hostOutBroadcastPkts object might be named hostOutBroadcastPkts.1.6.8.0.32.27.3.176"
INDEX { hostIndex, hostAddress } ::= { hostTable 1 }
HostEntry ::= SEQUENCE { hostAddress OCTET STRING, hostCreationOrder INTEGER (1..65535), hostIndex INTEGER (1..65535), hostInPkts Counter, hostOutPkts Counter, hostInOctets Counter, hostOutOctets Counter, hostOutErrors Counter, hostOutBroadcastPkts Counter, hostOutMulticastPkts Counter }
Now we're at the **hostTable** 🦋 It's just a list of host entries, and each **hostEntry** is a little stats folder for one host that got spotted on an interface. The index is **hostIndex** plus **hostAddress**, so the example name `hostOutBroadcastPkts.1.6.8.0.32.27.3.176` is literally the object name with the index bolted on at the end 🧚
hostAddress OBJECT-TYPE SYNTAX OCTET STRING ACCESS read-only STATUS mandatory DESCRIPTION "The physical address of this host." ::= { hostEntry 1 }
hostCreationOrder OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "An index that defines the relative ordering of the creation time of hosts captured for a particular hostControlEntry. This index shall be between 1 and N, where N is the value of the associated hostControlTableSize. The ordering of the indexes is based on the order of each entry's insertion into the table, in which entries added earlier have a lower index value than entries added later.
It is important to note that the order for a particular entry may change as an (earlier) entry is deleted from the table. Because this order may change, management stations should make use of the hostControlLastDeleteTime variable in the hostControlEntry associated with the relevant portion of the hostTable. By observing this variable, the management station may detect the circumstances where a previous association between a value of hostCreationOrder and a hostEntry may no longer hold." ::= { hostEntry 2 }
hostIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "The set of collected host statistics of which this entry is a part. The set of hosts identified by a particular value of this index is associated with the hostControlEntry as identified by the same value of hostControlIndex." ::= { hostEntry 3 }
Okay, **hostAddress** is just the host's physical address 📍 Then **hostCreationOrder** is the "who showed up first?" number 🥇 It runs from 1 up to the **hostControlTableSize**, and earlier arrivals get lower numbers. The tea ☕ is that the numbers can shift when an earlier host gets deleted, so the **hostControlLastDeleteTime** is how a management station can tell an old pairing might not be valid anymore 👀 **hostIndex** tells you which set of host stats the entry belongs to, matching the **hostControlIndex** of the same value 🫶
hostInPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of good packets transmitted to this address since it was added to the hostTable." ::= { hostEntry 4 }
hostOutPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of packets, including bad packets, transmitted by this address since it was added to the hostTable." ::= { hostEntry 5 }
hostInOctets OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of octets transmitted to this address since it was added to the hostTable (excluding framing bits but including FCS octets), except for those octets in bad packets." ::= { hostEntry 6 }
hostOutOctets OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of octets transmitted by this address since it was added to the hostTable (excluding framing bits but including FCS octets), including those octets in bad packets." ::= { hostEntry 7 }
hostOutErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of bad packets transmitted by this address since this host was added to the hostTable." ::= { hostEntry 8 }
hostOutBroadcastPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of good packets transmitted by this address that were directed to the broadcast address since this host was added to the hostTable." ::= { hostEntry 9 }
hostOutMulticastPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of good packets transmitted by this address that were directed to a multicast address since this host was added to the hostTable. Note that this number does not include packets directed to the broadcast address." ::= { hostEntry 10 }
The counters are where the real gossip lives 📊 **hostInPkts** counts the good packets sent *to* a host, while **hostOutPkts** counts *everything* a host sent, bad ones included 🙈 **hostInOctets** and **hostOutOctets** are the byte versions. Framing bits are excluded, FCS octets are included, and the in-direction skips bad packets while the out-direction doesn't 🧐 **hostOutErrors** is just the bad packets a host sent. And the broadcast and multicast ones split out the fancy traffic 📢, with multicast explicitly *not* including broadcast, so no double counting 💅
---
-- host Time Table
hostTimeTable OBJECT-TYPE SYNTAX SEQUENCE OF HostTimeEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of time-ordered host table entries."
::= { hosts 3 }
hostTimeEntry OBJECT-TYPE SYNTAX HostTimeEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A collection of statistics for a particular host that has been discovered on an interface of this device. This collection includes the relative ordering of the creation time of this object. For example, an instance of the hostTimeOutBroadcastPkts object might be named hostTimeOutBroadcastPkts.1.687" INDEX { hostTimeIndex, hostTimeCreationOrder } ::= { hostTimeTable 1 }
HostTimeEntry ::= SEQUENCE { hostTimeAddress OCTET STRING, hostTimeCreationOrder INTEGER (1..65535), hostTimeIndex INTEGER (1..65535), hostTimeInPkts Counter, hostTimeOutPkts Counter, hostTimeInOctets Counter, hostTimeOutOctets Counter, hostTimeOutErrors Counter, hostTimeOutBroadcastPkts Counter, hostTimeOutMulticastPkts Counter }
hostTimeAddress OBJECT-TYPE SYNTAX OCTET STRING ACCESS read-only STATUS mandatory DESCRIPTION "The physical address of this host." ::= { hostTimeEntry 1 }
Last stretch for this bit: the **hostTimeTable** is the time-ordered twin of the **hostTable** ⏳ Same vibe, but the index is **hostTimeIndex** plus **hostTimeCreationOrder**, so the rows come out in creation order. Each **hostTimeEntry** has the same collection of stats, just with the `hostTime` prefix, so an example name is `hostTimeOutBroadcastPkts.1.687` 🎀 And **hostTimeAddress** is the physical address of the host, same as before 🌈
<pink>okay bestie, we're still deep in the hostTime table and it is SO detailed 🎀💅</pink>
hostTimeCreationOrder OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "An index that uniquely identifies an entry in the hostTime table among those entries associated with the same hostControlEntry. This index shall be between 1 and N, where N is the value of the associated hostControlTableSize. The ordering of the indexes is based on the order of each entry's insertion into the table, in which entries added earlier have a lower index value than entries added later. Thus the management station has the ability to learn of new entries added to this table without downloading the entire table.
It is important to note that the index for a particular entry may change as an (earlier) entry is deleted from the table. Because this order may change, management stations should make use of the hostControlLastDeleteTime variable in the hostControlEntry associated with the relevant portion of the hostTimeTable. By observing this variable, the management station may detect the circumstances where a download of the table may have missed entries, and where a previous association between a value of hostTimeCreationOrder and a hostTimeEntry may no longer hold." ::= { hostTimeEntry 2 }
hostTimeIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "The set of collected host statistics of which this entry is a part. The set of hosts identified by a particular value of this index is associated with the hostControlEntry as identified by the same value of hostControlIndex." ::= { hostTimeEntry 3 }
hostTimeInPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of good packets transmitted to this address since it was added to the hostTimeTable." ::= { hostTimeEntry 4 }
hostTimeOutPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of god packets transmitted by this address since it was added to the hostTimeTable." ::= { hostTimeEntry 5 }
hostTimeInOctets OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of octets transmitted to this address since it was added to the hostTimeTable (excluding framing bits but including FCS octets), except for those octets in bad packets." ::= { hostTimeEntry 6 }
hostTimeOutOctets OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of octets transmitted by this address since it was added to the hostTimeTable (excluding framing bits but including FCS octets), including those octets in bad packets." ::= { hostTimeEntry 7 }
hostTimeOutErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of bad packets transmitted by this address since this host was added to the hostTimeTable." ::= { hostTimeEntry 8 }
hostTimeOutBroadcastPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of good packets transmitted by this address that were directed to the broadcast address since this host was added to the hostTimeTable." ::= { hostTimeEntry 9 }
hostTimeOutMulticastPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of good packets transmitted by this address that were directed to a multicast address since this host was added to the hostTimeTable. Note that this number does not include packets directed to the broadcast address." ::= { hostTimeEntry 10 }
-- The Host Top "N" Group
-- Implementation of the Host Top N group is optional. -- -- The Host Top N group requires the implementation of the -- host group. -- -- The Host Top N group is used to prepare reports that -- describe the hosts that top a list ordered by one of -- their statistics. -- The available statistics are samples of one of their -- base statistics, over an interval specified by the -- management station. Thus, these statistics are rate -- based. The management station also selects how many such -- hosts are reported.
-- The hostTopNControlTable is used to initiate the -- generation of such a report. The management station -- may select the parameters of such a report, such as -- which interface, which statistic, how many hosts, -- and the start and stop times of the sampling. When -- the report is prepared, entries are created in the -- hostTopNTable associated with the relevant -- hostTopNControlEntry. These entries are static for -- each report after it has been prepared.
hostTopNControlTable OBJECT-TYPE SYNTAX SEQUENCE OF HostTopNControlEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of top N host control entries." ::= { hostTopN 1 }
hostTopNControlEntry OBJECT-TYPE SYNTAX HostTopNControlEntry ACCESS not-accessible STATUS mandatory DESCRIPTION
"A set of parameters that control the creation of a report of the top N hosts according to several metrics. For example, an instance of the hostTopNDuration object might be named hostTopNDuration.3" INDEX { hostTopNControlIndex } ::= { hostTopNControlTable 1 }
HostTopNControlEntry ::= SEQUENCE { hostTopNControlIndex INTEGER (1..65535), hostTopNHostIndex INTEGER (1..65535), hostTopNRateBase INTEGER, hostTopNTimeRemaining INTEGER, hostTopNDuration INTEGER, hostTopNRequestedSize INTEGER, hostTopNGrantedSize INTEGER, hostTopNStartTime TimeTicks, hostTopNOwner OwnerString, hostTopNStatus EntryStatus }
hostTopNControlIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "An index that uniquely identifies an entry in the hostTopNControl table. Each such entry defines one top N report prepared for one interface." ::= { hostTopNControlEntry 1 }
hostTopNHostIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-write STATUS mandatory DESCRIPTION "The host table for which a top N report will be prepared on behalf of this entry. The host table identified by a particular value of this index is associated with the same host table as identified by the same value of hostIndex.
This object may not be modified if the associated hostTopNStatus object is equal to valid(1)." ::= { hostTopNControlEntry 2 }
hostTopNRateBase OBJECT-TYPE
SYNTAX INTEGER { hostTopNInPkts(1), hostTopNOutPkts(2), hostTopNInOctets(3), hostTopNOutOctets(4), hostTopNOutErrors(5), hostTopNOutBroadcastPkts(6), hostTopNOutMulticastPkts(7) } ACCESS read-write STATUS mandatory DESCRIPTION "The variable for each host that the hostTopNRate variable is based upon.
This object may not be modified if the associated hostTopNStatus object is equal to valid(1)." ::= { hostTopNControlEntry 3 }
hostTopNTimeRemaining OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION "The number of seconds left in the report currently being collected. When this object is modified by the management station, a new collection is started, possibly aborting a currently running report. The new value is used as the requested duration of this report, which is loaded into the associated hostTopNDuration object.
When this object is set to a non-zero value, any associated hostTopNEntries shall be made inaccessible by the monitor. While the value of this object is non-zero, it decrements by one per second until it reaches zero. During this time, all associated hostTopNEntries shall remain inaccessible. At the time that this object decrements to zero, the report is made accessible in the hostTopN table. Thus, the hostTopN table needs to be created only at the end of the collection interval." DEFVAL { 0 } ::= { hostTopNControlEntry 4 }
hostTopNDuration OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "The number of seconds that this report has collected during the last sampling interval, or if this report is currently being collected, the number of seconds that this report is being collected during this sampling interval.
When the associated hostTopNTimeRemaining object is set, this object shall be set by the probe to the same value and shall not be modified until the next time the hostTopNTimeRemaining is set.
This value shall be zero if no reports have been requested for this hostTopNControlEntry." DEFVAL { 0 } ::= { hostTopNControlEntry 5 }
hostTopNRequestedSize OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The maximum number of hosts requested for the top N
table.
When this object is created or modified, the probe
should set hostTopNGrantedSize as closely to this
object as is possible for the particular probe
implementation and available resources."
DEFVAL { 10 }
::= { hostTopNControlEntry 6 }
hostTopNGrantedSize OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The maximum number of hosts in the top N table.
When the associated hostTopNRequestedSize object is
created or modified, the probe should set this
object as closely to the requested value as is
possible for the particular implementation and
available resources. The probe must not lower this
value except as a result of a set to the associated
hostTopNRequestedSize object.
Hosts with the highest value of hostTopNRate shall be
placed in this table in decreasing order of this rate
until there is no more room or until there are no more
hosts."
::= { hostTopNControlEntry 7 }
hostTopNStartTime OBJECT-TYPE
SYNTAX TimeTicks
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The value of sysUpTime when this top N report was
last started. In other words, this is the time that
the associated hostTopNTimeRemaining object was
modified to start the requested report."
::= { hostTopNControlEntry 8 }
hostTopNOwner OBJECT-TYPE
SYNTAX OwnerString
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The entity that configured this entry and is
therefore using the resources assigned to it."
::= { hostTopNControlEntry 9 }
hostTopNStatus OBJECT-TYPE
SYNTAX EntryStatus
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The status of this hostTopNControl entry.
If this object is not equal to valid(1), all
associated hostTopNEntries shall be deleted by the
agent."
::= { hostTopNControlEntry 10 }
hostTopNTable OBJECT-TYPE
SYNTAX SEQUENCE OF HostTopNEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A list of top N host entries."
::= { hostTopN 2 }
hostTopNEntry OBJECT-TYPE
SYNTAX HostTopNEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A set of statistics for a host that is part of a
top N report. For example, an instance of the
hostTopNRate object might be named
hostTopNRate.3.10"
INDEX { hostTopNReport, hostTopNIndex }
::= { hostTopNTable 1 }
HostTopNEntry ::= SEQUENCE {
hostTopNReport INTEGER (1..65535),
hostTopNIndex INTEGER (1..65535),
hostTopNAddress OCTET STRING,
hostTopNRate INTEGER
}
hostTopNReport OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"This object identifies the top N report of which
this entry is a part. The set of hosts
identified by a particular value of this
object is part of the same report as identified
by the same value of the hostTopNControlIndex object."
::= { hostTopNEntry 1 }
hostTopNIndex OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"An index that uniquely identifies an entry in
the hostTopN table among those in the same report.
This index is between 1 and N, where N is the
number of entries in this table. Increasing values
of hostTopNIndex shall be assigned to entries with
decreasing values of hostTopNRate until index N
is assigned to the entry with the lowest value of
hostTopNRate or there are no more hostTopNEntries."
::= { hostTopNEntry 2 }
hostTopNAddress OBJECT-TYPE
SYNTAX OCTET STRING
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The physical address of this host."
::= { hostTopNEntry 3 }
hostTopNRate OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The amount of change in the selected variable
during this sampling interval. The selected
variable is this host's instance of the object
selected by hostTopNRateBase."
::= { hostTopNEntry 4 }
Okay, so now we're in <lavender>the Matrix Group</lavender> 🦋 and it's giving conversation tracking, bestie 💅. The comments at the top of this block explain how it works, so read them right there ✨
-- The Matrix Group
-- Implementation of the Matrix group is optional.
--
-- The Matrix group consists of the matrixControlTable,
-- matrixSDTable and the matrixDSTable. These tables
-- store statistics for a particular conversation
-- between two addresses. As the device detects a new
-- conversation, including those to a non-unicast
-- address, it creates a new entry in both of the
-- matrix tables. It must only create new entries
-- based on information received in good packets. If
-- the monitoring device finds itself short of
-- resources, it may delete entries as needed. It is
-- suggested that the device delete the least recently
-- used entries first.
matrixControlTable OBJECT-TYPE
SYNTAX SEQUENCE OF MatrixControlEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A list of information entries for the
traffic matrix on each interface."
::= { matrix 1 }
matrixControlEntry OBJECT-TYPE
SYNTAX MatrixControlEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"Information about a traffic matrix on a particular
interface. For example, an instance of the
matrixControlLastDeleteTime object might be named
matrixControlLastDeleteTime.1"
INDEX { matrixControlIndex }
::= { matrixControlTable 1 }
MatrixControlEntry ::= SEQUENCE {
matrixControlIndex INTEGER (1..65535),
matrixControlDataSource OBJECT IDENTIFIER,
matrixControlTableSize INTEGER,
matrixControlLastDeleteTime TimeTicks,
matrixControlOwner OwnerString,
matrixControlStatus EntryStatus
}
matrixControlIndex OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"An index that uniquely identifies an entry in the
matrixControl table. Each such entry defines
a function that discovers conversations on a
particular interface and places statistics about
them in the matrixSDTable and the matrixDSTable on
behalf of this matrixControlEntry."
::= { matrixControlEntry 1 }
matrixControlDataSource OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"This object identifies the source of
the data from which this entry creates a traffic
matrix. This source can be any interface on this
device. In order to identify a particular
interface, this object shall identify the instance
of the ifIndex object, defined in RFC 1213 and RFC
1573 [4,6], for the desired interface. For example,
if an entry were to receive data from interface #1,
this object would be set to ifIndex.1.
The statistics in this group reflect all packets
on the local network segment attached to the
identified interface.
An agent may or may not be able to tell if
fundamental changes to the media of the interface
have occurred and necessitate an invalidation of
this entry. For example, a hot-pluggable ethernet
card could be pulled out and replaced by a
token-ring card. In such a case, if the agent has
such knowledge of the change, it is recommended that
it invalidate this entry.
This object may not be modified if the associated
matrixControlStatus object is equal to valid(1)."
::= { matrixControlEntry 2 }
matrixControlTableSize OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of matrixSDEntries in the matrixSDTable
for this interface. This must also be the value of
the number of entries in the matrixDSTable for this
interface."
::= { matrixControlEntry 3 }
matrixControlLastDeleteTime OBJECT-TYPE
SYNTAX TimeTicks
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The value of sysUpTime when the last entry
was deleted from the portion of the matrixSDTable
or matrixDSTable associated with this
matrixControlEntry. If no deletions have occurred,
this value shall be zero."
::= { matrixControlEntry 4 }
matrixControlOwner OBJECT-TYPE
SYNTAX OwnerString
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The entity that configured this entry and is
therefore using the resources assigned to it."
::= { matrixControlEntry 5 }
matrixControlStatus OBJECT-TYPE
SYNTAX EntryStatus
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The status of this matrixControl entry.
If this object is not equal to valid(1), all
associated entries in the matrixSDTable and the
matrixDSTable shall be deleted by the agent."
::= { matrixControlEntry 6 }
matrixSDTable OBJECT-TYPE SYNTAX SEQUENCE OF MatrixSDEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of traffic matrix entries indexed by source and destination MAC address." ::= { matrix 2 }
matrixSDEntry OBJECT-TYPE SYNTAX MatrixSDEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A collection of statistics for communications between two addresses on a particular interface. For example, an instance of the matrixSDPkts object might be named matrixSDPkts.1.6.8.0.32.27.3.176.6.8.0.32.10.8.113" INDEX { matrixSDIndex, matrixSDSourceAddress, matrixSDDestAddress } ::= { matrixSDTable 1 }
MatrixSDEntry ::= SEQUENCE { matrixSDSourceAddress OCTET STRING, matrixSDDestAddress OCTET STRING, matrixSDIndex INTEGER (1..65535), matrixSDPkts Counter, matrixSDOctets Counter, matrixSDErrors Counter }
matrixSDSourceAddress OBJECT-TYPE SYNTAX OCTET STRING ACCESS read-only STATUS mandatory DESCRIPTION "The source physical address." ::= { matrixSDEntry 1 }
matrixSDDestAddress OBJECT-TYPE
SYNTAX OCTET STRING ACCESS read-only STATUS mandatory DESCRIPTION "The destination physical address." ::= { matrixSDEntry 2 }
matrixSDIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "The set of collected matrix statistics of which this entry is a part. The set of matrix statistics identified by a particular value of this index is associated with the same matrixControlEntry as identified by the same value of matrixControlIndex." ::= { matrixSDEntry 3 }
matrixSDPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of packets transmitted from the source address to the destination address (this number includes bad packets)." ::= { matrixSDEntry 4 }
matrixSDOctets OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of octets (excluding framing bits but including FCS octets) contained in all packets transmitted from the source address to the destination address." ::= { matrixSDEntry 5 }
matrixSDErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of bad packets transmitted from the source address to the destination address."
::= { matrixSDEntry 6 }
-- Traffic matrix tables from destination to source
matrixDSTable OBJECT-TYPE SYNTAX SEQUENCE OF MatrixDSEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of traffic matrix entries indexed by destination and source MAC address." ::= { matrix 3 }
matrixDSEntry OBJECT-TYPE SYNTAX MatrixDSEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A collection of statistics for communications between two addresses on a particular interface. For example, an instance of the matrixSDPkts object might be named matrixSDPkts.1.6.8.0.32.10.8.113.6.8.0.32.27.3.176" INDEX { matrixDSIndex, matrixDSDestAddress, matrixDSSourceAddress } ::= { matrixDSTable 1 }
MatrixDSEntry ::= SEQUENCE { matrixDSSourceAddress OCTET STRING, matrixDSDestAddress OCTET STRING, matrixDSIndex INTEGER (1..65535), matrixDSPkts Counter, matrixDSOctets Counter, matrixDSErrors Counter }
matrixDSSourceAddress OBJECT-TYPE SYNTAX OCTET STRING ACCESS read-only STATUS mandatory DESCRIPTION "The source physical address." ::= { matrixDSEntry 1 }
matrixDSDestAddress OBJECT-TYPE SYNTAX OCTET STRING ACCESS read-only STATUS mandatory DESCRIPTION "The destination physical address." ::= { matrixDSEntry 2 }
matrixDSIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "The set of collected matrix statistics of which this entry is a part. The set of matrix statistics identified by a particular value of this index is associated with the same matrixControlEntry as identified by the same value of matrixControlIndex." ::= { matrixDSEntry 3 }
matrixDSPkts OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of packets transmitted from the source address to the destination address (this number includes bad packets)." ::= { matrixDSEntry 4 }
matrixDSOctets OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of octets (excluding framing bits but including FCS octets) contained in all packets transmitted from the source address to the destination address." ::= { matrixDSEntry 5 }
matrixDSErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of bad packets transmitted from the source address to the destination address." ::= { matrixDSEntry 6 }
<pink>okay the DS table is literally the SD table flipped around, so it's indexed by destination first and then source 💅🦋</pink>
-- The Filter Group
-- Implementation of the Filter group is optional. -- -- The Filter group allows packets to be captured with an -- arbitrary filter expression. A logical data and -- event stream or "channel" is formed by the packets -- that match the filter expression. -- -- This filter mechanism allows the creation of an arbitrary -- logical expression with which to filter packets. Each -- filter associated with a channel is OR'ed with the others. -- Within a filter, any bits checked in the data and status -- are AND'ed with respect to other bits in the same filter. -- The NotMask also allows for checking for inequality. -- Finally, the channelAcceptType object allows for -- inversion of the whole equation. -- -- If a management station wishes to receive a trap to alert -- it that new packets have been captured and are available -- for download, it is recommended that it set up an alarm -- entry that monitors the value of the relevant -- channelMatches instance. -- -- The channel can be turned on or off, and can also -- generate events when packets pass through it.
filterTable OBJECT-TYPE SYNTAX SEQUENCE OF FilterEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of packet filter entries." ::= { filter 1 }
filterEntry OBJECT-TYPE SYNTAX FilterEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A set of parameters for a packet filter applied on a particular interface. As an example, an instance of the filterPktData object might be named filterPktData.12" INDEX { filterIndex } ::= { filterTable 1 }
FilterEntry ::= SEQUENCE { filterIndex INTEGER (1..65535), filterChannelIndex INTEGER (1..65535), filterPktDataOffset INTEGER, filterPktData OCTET STRING, filterPktDataMask OCTET STRING, filterPktDataNotMask OCTET STRING, filterPktStatus INTEGER, filterPktStatusMask INTEGER, filterPktStatusNotMask INTEGER, filterOwner OwnerString, filterStatus EntryStatus }
filterIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "An index that uniquely identifies an entry in the filter table. Each such entry defines one filter that is to be applied to every packet received on an interface." ::= { filterEntry 1 }
filterChannelIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-write STATUS mandatory DESCRIPTION "This object identifies the channel of which this filter is a part. The filters identified by a particular value of this object are associated with the same channel as identified by the same value of the channelIndex object." ::= { filterEntry 2 }
filterPktDataOffset OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION "The offset from the beginning of each packet where a match of packet data will be attempted. This offset is measured from the point in the physical layer packet after the framing bits, if any. For example, in an Ethernet frame, this point is at the beginning of the destination MAC address.
This object may not be modified if the associated filterStatus object is equal to valid(1)." DEFVAL { 0 } ::= { filterEntry 3 }
okay so the matching logic is where it gets *spicy* 🌶️ these next objects decide which packets actually make it through the filter 🎀
filterPktData OBJECT-TYPE SYNTAX OCTET STRING ACCESS read-write STATUS mandatory DESCRIPTION "The data that is to be matched with the input packet. For each packet received, this filter and the accompanying filterPktDataMask and filterPktDataNotMask will be adjusted for the offset. The only bits relevant to this match algorithm are those that have the corresponding filterPktDataMask bit equal to one. The following three rules are then applied to every packet:
(1) If the packet is too short and does not have data corresponding to part of the filterPktData, the packet will fail this data match.
(2) For each relevant bit from the packet with the corresponding filterPktDataNotMask bit set to zero, if the bit from the packet is not equal to the corresponding bit from the filterPktData, then the packet will fail this data match.
(3) If for every relevant bit from the packet with the corresponding filterPktDataNotMask bit set to one, the bit from the packet is equal to the corresponding bit from the filterPktData, then the packet will fail this data match.
Any packets that have not failed any of the three matches above have passed this data match. In particular, a zero length filter will match any packet.
This object may not be modified if the associated filterStatus object is equal to valid(1)." ::= { filterEntry 4 }
so `filterPktData` is the actual bytes you're hunting for 🦋 before anything else happens, the offset gets applied to it, and only the bits where the mask is `1` even count. then three checks run on every packet:
1. if the packet is too short to cover the bytes in `filterPktData`, it's a fail 💀
2. for the bits where the NotMask is `0`, the packet's bit has to match the filter's bit, or it's out 🙅♀️
3. for the bits where the NotMask is `1`, if they *all* match the filter, it's out too 🚫
anything that survives all three passes, periodt ✨ and a zero length filter matches literally everything, which is giving "no filter, no problem" 🌸 also you can't touch this object while the `filterStatus` is `valid(1)` 🔒
filterPktDataMask OBJECT-TYPE SYNTAX OCTET STRING ACCESS read-write STATUS mandatory DESCRIPTION "The mask that is applied to the match process. After adjusting this mask for the offset, only those bits in the received packet that correspond to bits set in this mask are relevant for further processing by the match algorithm. The offset is applied to filterPktDataMask in the same way it is applied to the filter. For the purposes of the matching algorithm, if the associated filterPktData object is longer than this mask, this mask is conceptually extended with '1' bits until it reaches the length of the filterPktData object.
This object may not be modified if the associated filterStatus object is equal to valid(1)." ::= { filterEntry 5 }
ok so `filterPktDataMask` is the spotlight 🔦 it picks which bits in the packet get looked at. the offset gets applied to it the same way as the filter itself 💖 and if `filterPktData` is longer than the mask, the mask gets padded out with `1` bits until it's the same length, so the extra bytes still count 👀
filterPktDataNotMask OBJECT-TYPE SYNTAX OCTET STRING ACCESS read-write STATUS mandatory DESCRIPTION "The inversion mask that is applied to the match process. After adjusting this mask for the offset, those relevant bits in the received packet that correspond to bits cleared in this mask must all be equal to their corresponding bits in the filterPktData object for the packet to be accepted. In addition, at least one of those relevant bits in the received packet that correspond to bits set in this mask must be different to its corresponding bit in the filterPktData object.
For the purposes of the matching algorithm, if the associated filterPktData object is longer than this mask, this mask is conceptually extended with '0' bits until it reaches the length of the filterPktData object.
This object may not be modified if the associated filterStatus object is equal to valid(1)." ::= { filterEntry 6 }
this one is the plot twist 🌀 `filterPktDataNotMask` is the *inversion* mask. where it's cleared, the packet bits have to line up with the filter. where it's set, at least one of those bits has to be different from the filter, or the packet doesn't get in 🙈 same padding rule applies, except this time the extra bits get padded with `0`s 🧚
filterPktStatus OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION
"The status that is to be matched with the input packet. The only bits relevant to this match algorithm are those that have the corresponding filterPktStatusMask bit equal to one. The following two rules are then applied to every packet:
(1) For each relevant bit from the packet status with the corresponding filterPktStatusNotMask bit set to zero, if the bit from the packet status is not equal to the corresponding bit from the filterPktStatus, then the packet will fail this status match.
(2) If for every relevant bit from the packet status with the corresponding filterPktStatusNotMask bit set to one, the bit from the packet status is equal to the corresponding bit from the filterPktStatus, then the packet will fail this status match.
Any packets that have not failed either of the two matches above have passed this status match. In particular, a zero length status filter will match any packet's status.
The value of the packet status is a sum. This sum initially takes the value zero. Then, for each error, E, that has been discovered in this packet, 2 raised to a value representing E is added to the sum. The errors and the bits that represent them are dependent on the media type of the interface that this channel is receiving packets from.
The errors defined for a packet captured off of an Ethernet interface are as follows:
bit # Error 0 Packet is longer than 1518 octets 1 Packet is shorter than 64 octets 2 Packet experienced a CRC or Alignment error
For example, an Ethernet fragment would have a value of 6 (2^1 + 2^2).
As this MIB is expanded to new media types, this object will have other media-specific errors defined.
For the purposes of this status matching algorithm, if the packet status is longer than this filterPktStatus object, this object is conceptually extended with '0' bits until it reaches the size of the packet status.
This object may not be modified if the associated filterStatus object is equal to valid(1)." ::= { filterEntry 7 }
ok the status side is basically the same vibe but for the *errors* a packet picked up 🐛 `filterPktStatus` is a sum: start at zero, and every error the packet has adds `2` raised to that error's bit number ➕ which bits mean what depends on the media type of the interface. for Ethernet 🔌 bit `0` is "longer than 1518 octets", bit `1` is "shorter than 64 octets", and bit `2` is "CRC or Alignment error". so an Ethernet fragment is `6` (`2^1 + 2^2`), which is just iykyk math 🧮 more media types will get their own errors later too 🌈
filterPktStatusMask OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION "The mask that is applied to the status match process. Only those bits in the received packet that correspond to bits set in this mask are relevant for further processing by the status match algorithm. For the purposes of the matching algorithm, if the associated filterPktStatus object is longer than this mask, this mask is conceptually extended with '1' bits until it reaches the size of the filterPktStatus. In addition, if a packet status is longer than this mask, this mask is conceptually extended with '0' bits until it reaches the size of the packet status.
This object may not be modified if the associated filterStatus object is equal to valid(1)." ::= { filterEntry 8 }
`filterPktStatusMask` is the status version of the spotlight 🔦 only the bits it points at get checked. same padding energy: `1`s for the filter if the filter is longer, `0`s for the packet status if that's longer 🫶
filterPktStatusNotMask OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION "The inversion mask that is applied to the status match process. Those relevant bits in the received packet status that correspond to bits cleared in this mask must all be equal to their corresponding bits in the filterPktStatus object for the packet to be accepted. In addition, at least one of those relevant bits in the received packet status that correspond to bits set in this mask must be different to its corresponding bit in the filterPktStatus object for the packet to be accepted.
For the purposes of the matching algorithm, if the associated filterPktStatus object or a packet status is longer than this mask, this mask is conceptually extended with '0' bits until it reaches the longer of the lengths of the filterPktStatus object and the packet status.
This object may not be modified if the associated filterStatus object is equal to valid(1)." ::= { filterEntry 9 }
and the status inversion mask works exactly like `filterPktDataNotMask` 🌀 cleared bits have to match, and at least one set bit has to be different, same as before, just pointed at the status instead of the packet bytes 💅 it gets padded with `0`s to the longer of the two lengths.
filterOwner OBJECT-TYPE SYNTAX OwnerString ACCESS read-write STATUS mandatory DESCRIPTION "The entity that configured this entry and is therefore using the resources assigned to it." ::= { filterEntry 10 }
filterStatus OBJECT-TYPE SYNTAX EntryStatus ACCESS read-write STATUS mandatory DESCRIPTION "The status of this filter entry." ::= { filterEntry 11 }
`filterOwner` is the entity that set the entry up and is therefore using the resources for it 👑 and `filterStatus` is the entry's own status 🦋
channelTable OBJECT-TYPE SYNTAX SEQUENCE OF ChannelEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of packet channel entries." ::= { filter 2 }
channelEntry OBJECT-TYPE SYNTAX ChannelEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A set of parameters for a packet channel applied on a particular interface. As an example, an instance of the channelMatches object might be named channelMatches.3" INDEX { channelIndex } ::= { channelTable 1 }
ChannelEntry ::= SEQUENCE { channelIndex INTEGER (1..65535), channelIfIndex INTEGER (1..65535), channelAcceptType INTEGER, channelDataControl INTEGER, channelTurnOnEventIndex INTEGER (0..65535), channelTurnOffEventIndex INTEGER (0..65535), channelEventIndex INTEGER (0..65535), channelEventStatus INTEGER, channelMatches Counter, channelDescription DisplayString (SIZE (0..127)), channelOwner OwnerString, channelStatus EntryStatus }
and now we're on to the **channel table** 📡 it's the list of packet channel entries, and each channel is a set of parameters for packets on one particular interface 🌸 the example name in the spec is `channelMatches.3`, which is literally giving "channel number three's match counter" 💜 the `INDEX` is `channelIndex`, and `ChannelEntry` is the full lineup of fields in there ✨
okay so the channel table is where filters get wired up to an interface and the data stream gets switched on and off, and it is giving very organized energy 💅🦋
channelIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "An index that uniquely identifies an entry in the channel table. Each such entry defines one channel, a logical data and event stream.
It is suggested that before creating a channel, an application should scan all instances of the filterChannelIndex object to make sure that there are no pre-existing filters that would be inadvertently be linked to the channel." ::= { channelEntry 1 }
channelIfIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-write STATUS mandatory DESCRIPTION "The value of this object uniquely identifies the interface on this remote network monitoring device to which the associated filters are applied to allow data into this channel. The interface identified by a particular value of this object is the same interface as identified by the same value of the ifIndex object, defined in RFC 1213 and RFC 1573 [4,6].
The filters in this group are applied to all packets on the local network segment attached to the identified interface.
An agent may or may not be able to tell if fundamental changes to the media of the interface have occurred and necessitate an invalidation of this entry. For example, a hot-pluggable ethernet card could be pulled out and replaced by a token-ring card. In such a case, if the agent has such knowledge of the change, it is recommended that it invalidate this entry.
This object may not be modified if the associated channelStatus object is equal to valid(1)." ::= { channelEntry 2 }
channelAcceptType OBJECT-TYPE SYNTAX INTEGER { acceptMatched(1), acceptFailed(2) } ACCESS read-write STATUS mandatory DESCRIPTION "This object controls the action of the filters associated with this channel. If this object is equal to acceptMatched(1), packets will be accepted to this channel if they are accepted by both the packet data and packet status matches of an associated filter. If this object is equal to acceptFailed(2), packets will be accepted to this channel only if they fail either the packet data match or the packet status match of each of the associated filters.
In particular, a channel with no associated filters will match no packets if set to acceptMatched(1) case and will match all packets in the acceptFailed(2) case.
This object may not be modified if the associated channelStatus object is equal to valid(1)." ::= { channelEntry 3 }
channelDataControl OBJECT-TYPE SYNTAX INTEGER { on(1), off(2) } ACCESS read-write STATUS mandatory DESCRIPTION
"This object controls the flow of data through this channel. If this object is on(1), data, status and events flow through this channel. If this object is off(2), data, status and events will not flow through this channel." DEFVAL { off } ::= { channelEntry 4 }
channelTurnOnEventIndex OBJECT-TYPE SYNTAX INTEGER (0..65535) ACCESS read-write STATUS mandatory DESCRIPTION "The value of this object identifies the event that is configured to turn the associated channelDataControl from off to on when the event is generated. The event identified by a particular value of this object is the same event as identified by the same value of the eventIndex object. If there is no corresponding entry in the eventTable, then no association exists. In fact, if no event is intended for this channel, channelTurnOnEventIndex must be set to zero, a non-existent event index.
This object may not be modified if the associated channelStatus object is equal to valid(1)." ::= { channelEntry 5 }
channelTurnOffEventIndex OBJECT-TYPE SYNTAX INTEGER (0..65535) ACCESS read-write STATUS mandatory DESCRIPTION "The value of this object identifies the event that is configured to turn the associated channelDataControl from on to off when the event is generated. The event identified by a particular value of this object is the same event as identified by the same value of the eventIndex object. If there is no corresponding entry in the eventTable, then no association exists. In fact, if no event is intended for this channel, channelTurnOffEventIndex must be set to zero, a non-existent event index.
This object may not be modified if the associated channelStatus object is equal to valid(1)." ::= { channelEntry 6 }
channelEventIndex OBJECT-TYPE SYNTAX INTEGER (0..65535) ACCESS read-write STATUS mandatory DESCRIPTION "The value of this object identifies the event that is configured to be generated when the associated channelDataControl is on and a packet is matched. The event identified by a particular value of this object is the same event as identified by the same value of the eventIndex object. If there is no corresponding entry in the eventTable, then no association exists. In fact, if no event is intended for this channel, channelEventIndex must be set to zero, a non-existent event index.
This object may not be modified if the associated channelStatus object is equal to valid(1)." ::= { channelEntry 7 }
channelEventStatus OBJECT-TYPE SYNTAX INTEGER { eventReady(1), eventFired(2), eventAlwaysReady(3) } ACCESS read-write STATUS mandatory DESCRIPTION "The event status of this channel.
If this channel is configured to generate events when packets are matched, a means of controlling the flow of those events is often needed. When this object is equal to eventReady(1), a single event may be generated, after which this object will be set by the probe to eventFired(2). While in the eventFired(2) state, no events will be generated until the object is modified to eventReady(1) (or eventAlwaysReady(3)). The management station can thus easily respond to a notification of an event by re-enabling this object.
If the management station wishes to disable this flow control and allow events to be generated at will, this object may be set to eventAlwaysReady(3). Disabling the flow control is discouraged as it can result in high network traffic or other performance problems." DEFVAL { eventReady } ::= { channelEntry 8 }
channelMatches OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of times this channel has matched a packet. Note that this object is updated even when channelDataControl is set to off." ::= { channelEntry 9 }
channelDescription OBJECT-TYPE SYNTAX DisplayString (SIZE (0..127)) ACCESS read-write STATUS mandatory DESCRIPTION "A comment describing this channel." ::= { channelEntry 10 }
channelOwner OBJECT-TYPE SYNTAX OwnerString ACCESS read-write STATUS mandatory DESCRIPTION "The entity that configured this entry and is therefore using the resources assigned to it." ::= { channelEntry 11 }
channelStatus OBJECT-TYPE SYNTAX EntryStatus ACCESS read-write STATUS mandatory DESCRIPTION "The status of this channel entry." ::= { channelEntry 12 }
Now we're in the Packet Capture Group 🎀 this is the bit where you capture the packets that matched your filters, and the code comments literally explain how the tables link up 🧚
-- The Packet Capture Group
-- Implementation of the Packet Capture group is optional. -- -- The Packet Capture Group requires implementation of the -- Filter Group. -- -- The Packet Capture group allows packets to be captured -- upon a filter match. The bufferControlTable controls -- the captured packets output from a channel that is -- associated with it. The captured packets are placed -- in entries in the captureBufferTable. These entries are -- associated with the bufferControlEntry on whose behalf they -- were stored.
bufferControlTable OBJECT-TYPE SYNTAX SEQUENCE OF BufferControlEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of buffers control entries." ::= { capture 1 }
bufferControlEntry OBJECT-TYPE SYNTAX BufferControlEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A set of parameters that control the collection of a stream of packets that have matched filters. As an example, an instance of the bufferControlCaptureSliceSize object might be named bufferControlCaptureSliceSize.3" INDEX { bufferControlIndex } ::= { bufferControlTable 1 }
BufferControlEntry ::= SEQUENCE { bufferControlIndex INTEGER (1..65535), bufferControlChannelIndex INTEGER (1..65535), bufferControlFullStatus INTEGER, bufferControlFullAction INTEGER, bufferControlCaptureSliceSize INTEGER, bufferControlDownloadSliceSize INTEGER, bufferControlDownloadOffset INTEGER, bufferControlMaxOctetsRequested INTEGER, bufferControlMaxOctetsGranted INTEGER, bufferControlCapturedPackets INTEGER, bufferControlTurnOnTime TimeTicks, bufferControlOwner OwnerString, bufferControlStatus EntryStatus }
okay so this is the **bufferControlEntry** row, and it's basically the whole personality of a capture buffer in one struct 🎀 Every column below is one knob you can turn, so let's go through them bestie-style ✨
**bufferControlIndex** 🔑 This is the unique ID for each row, and it's never zero, periodt. Each row is one set of captured packets that gets controlled by one or more filters.
bufferControlIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "An index that uniquely identifies an entry in the bufferControl table. The value of this index shall never be zero. Each such entry defines one set of packets that is captured and controlled by one or more filters." ::= { bufferControlEntry 1 }
**bufferControlChannelIndex** 📡 This one picks which channel is the source of packets for the buffer. It matches the channelIndex object, so the numbers line up across tables, which is so satisfying 🦋 It's read-write, but you can't touch it while the row is valid(1). No cap, that's a locked-in look 🔒
bufferControlChannelIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-write STATUS mandatory DESCRIPTION "An index that identifies the channel that is the source of packets for this bufferControl table. The channel identified by a particular value of this index is the same as identified by the same value of the channelIndex object.
This object may not be modified if the associated bufferControlStatus object is equal to valid(1)." ::= { bufferControlEntry 2 }
**bufferControlFullStatus** 🪣 This is the "is there room?" indicator, and it's either spaceAvailable(1) or full(2). When it's full and the action is wrapWhenFull, the buffer keeps taking new packets by quietly deleting the oldest ones 🌀 When it's full and the action is lockWhenFull, the buffer has basically stopped collecting, so it's a hard stop 🛑 The big rule is that once it's full(2), the probe must not later flip it back to spaceAvailable(1) unless there's a real jump in resources, like bufferControlOctetsGranted going up. The wrap-mode deleting must not change this value either, which is a very serious no-touch zone 💅
bufferControlFullStatus OBJECT-TYPE SYNTAX INTEGER { spaceAvailable(1), full(2) } ACCESS read-only STATUS mandatory DESCRIPTION "This object shows whether the buffer has room to accept new packets or if it is full.
If the status is spaceAvailable(1), the buffer is accepting new packets normally. If the status is full(2) and the associated bufferControlFullAction object is wrapWhenFull, the buffer is accepting new packets by deleting enough of the oldest packets to make room for new ones as they arrive. Otherwise, if the status is full(2) and the bufferControlFullAction object is lockWhenFull, then the buffer has stopped collecting packets.
When this object is set to full(2) the probe must not later set it to spaceAvailable(1) except in the case of a significant gain in resources such as an increase of bufferControlOctetsGranted. In particular, the wrap-mode action of deleting old packets to make room for newly arrived packets must not affect the value of this object." ::= { bufferControlEntry 3 }
**bufferControlFullAction** 🎬 This decides what the buffer does when it hits full. There are two options: lockWhenFull(1) and wrapWhenFull(2), which is the FIFO one 🫧 In lock mode, the packet that fills the buffer sets bufferControlFullStatus to full(2), and then the buffer stops capturing. Iconic.
bufferControlFullAction OBJECT-TYPE SYNTAX INTEGER { lockWhenFull(1), wrapWhenFull(2) -- FIFO } ACCESS read-write STATUS mandatory DESCRIPTION "Controls the action of the buffer when it reaches the full status. When in the lockWhenFull(1) state and a packet is added to the buffer that fills the buffer, the bufferControlFullStatus will be set to full(2) and this buffer will stop capturing packets." ::= { bufferControlEntry 4 }
**bufferControlCaptureSliceSize** ✂️ This is how many octets of each packet get saved. The example is giving main character energy: a 1500 octet packet with this set to 500 only stores 500 octets 💖 If it's set to 0, the buffer saves as many octets as it can. It defaults to 100, and like the channel index, it can't be changed while the row is valid(1) 🔒
bufferControlCaptureSliceSize OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION "The maximum number of octets of each packet that will be saved in this capture buffer. For example, if a 1500 octet packet is received by the probe and this object is set to 500, then only 500 octets of the packet will be stored in the associated capture buffer. If this variable is set to 0, the capture buffer will save as many octets as is possible.
This object may not be modified if the associated bufferControlStatus object is equal to valid(1)." DEFVAL { 100 } ::= { bufferControlEntry 5 }
**bufferControlDownloadSliceSize** 📦 This one is about what you get back when you retrieve packets over SNMP. It caps how many octets of each stored packet come back in the response. The example is the same as before: 500 stored octets, offset 0, slice set to 100, so you only get the first 100 octets 🎀 There's also a very wise warning here. A prudent manager thinks about interoperability and fragmentation before setting this too big, because conformant SNMP implementations aren't required to accept messages longer than 484 octets, even though they're encouraged to handle bigger datagrams when they can. So keep it sensible, bestie 🫶 Defaults to 100.
bufferControlDownloadSliceSize OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION "The maximum number of octets of each packet in this capture buffer that will be returned in an SNMP retrieval of that packet. For example, if 500 octets of a packet have been stored in the associated capture buffer, the associated bufferControlDownloadOffset is 0, and this object is set to 100, then the captureBufferPacket object that contains the packet will contain only the first 100 octets of the packet.
A prudent manager will take into account possible interoperability or fragmentation problems that may occur if the download slice size is set too large. In particular, conformant SNMP implementations are not required to accept messages whose length exceeds 484 octets, although they are encouraged to support larger datagrams whenever feasible." DEFVAL { 100 } ::= { bufferControlEntry 6 }
**bufferControlDownloadOffset** 🦋 This is where the download starts. It's the offset of the first octet returned in an SNMP retrieval. With 500 stored octets and this set to 100, the captureBufferPacket object starts 100 octets into the packet. Defaults to 0, aka "from the very beginning," which is honestly the most relatable default ever 🥹
bufferControlDownloadOffset OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION "The offset of the first octet of each packet in this capture buffer that will be returned in an SNMP retrieval of that packet. For example, if 500 octets of a packet have been stored in the associated capture buffer and this object is set to 100, then the captureBufferPacket object that contains the packet will contain bytes starting 100 octets into the packet." DEFVAL { 0 } ::= { bufferControlEntry 7 }
**bufferControlMaxOctetsRequested** 🙏 This is the wish list. It's the max number of octets you'd like this buffer to hold, overhead included. If you set it to -1, you're asking for as many octets as possible 🌈 When it's created or modified, the probe should try to get bufferControlMaxOctetsGranted as close to this number as it can, based on its own implementation and resources. The exception is -1: if you ask for -1, the probe must set the granted value to -1 too, no negotiating 💅 Defaults to -1.
bufferControlMaxOctetsRequested OBJECT-TYPE SYNTAX INTEGER ACCESS read-write STATUS mandatory DESCRIPTION "The requested maximum number of octets to be saved in this captureBuffer, including any implementation-specific overhead. If this variable is set to -1, the capture buffer will save as many octets as is possible.
When this object is created or modified, the probe should set bufferControlMaxOctetsGranted as closely to this object as is possible for the particular probe implementation and available resources. However, if the object has the special value of -1, the probe must set bufferControlMaxOctetsGranted to -1." DEFVAL { -1 } ::= { bufferControlEntry 8 }
**bufferControlMaxOctetsGranted** 🎟️ This is the actual limit the probe agreed to, including overhead. It's read-only, because the probe decides it, not you 🙈 If it's -1, the buffer saves as many octets as possible. The probe must not lower this value except because bufferControlMaxOctetsRequested was changed. When the buffer is full and the packet's action is wrapWhenFull(2), the agent deletes enough of the oldest packets to fit the new one. If the action is lockWhenFull(1), the new packet gets thrown away. Either way, bufferControlFullStatus has to become full(2). If the limit drops, the agent deletes the oldest captureBufferEntries until the octets used fit under the new value. If the limit goes up, the number of entries is allowed to grow. Lots of rules, very intense, and it's all about keeping the buffer honest 🥰
bufferControlMaxOctetsGranted OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "The maximum number of octets that can be saved in this captureBuffer, including overhead. If this variable is -1, the capture buffer will save as many octets as possible.
When the bufferControlMaxOctetsRequested object is created or modified, the probe should set this object as closely to the requested value as is possible for the particular probe implementation and available resources. However, if the request object has the special value of -1, the probe must set this object to -1. The probe must not lower this value except as a result of a modification to the associated bufferControlMaxOctetsRequested object.
When this maximum number of octets is reached and a new packet is to be added to this capture buffer and the corresponding bufferControlFullAction is set to wrapWhenFull(2), enough of the oldest packets associated with this capture buffer shall be deleted by the agent so that the new packet can be added. If the corresponding bufferControlFullAction is set to lockWhenFull(1), the new packet shall be discarded. In either case, the probe must set bufferControlFullStatus to full(2).
When the value of this object changes to a value less than the current value, entries are deleted from the captureBufferTable associated with this bufferControlEntry. Enough of the oldest of these captureBufferEntries shall be deleted by the agent so that the number of octets used remains less than or equal to the new value of this object.
When the value of this object changes to a value greater than the current value, the number of associated captureBufferEntries may be allowed to grow." ::= { bufferControlEntry 9 }
**bufferControlCapturedPackets** 📊 A simple read-only count of how many packets are sitting in this capture buffer right now. Quick and clean 🧁
bufferControlCapturedPackets OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "The number of packets currently in this captureBuffer." ::= { bufferControlEntry 10 }
**bufferControlTurnOnTime** ⏰ This is the sysUpTime value from when the capture buffer was first turned on. It's a timestamp, so you can tell how long the party's been going 🥳
bufferControlTurnOnTime OBJECT-TYPE SYNTAX TimeTicks ACCESS read-only STATUS mandatory DESCRIPTION "The value of sysUpTime when this capture buffer was first turned on." ::= { bufferControlEntry 11 }
**bufferControlOwner** 👑 This is the entity that set up the entry and is therefore using the resources assigned to it. Whoever's name is on it is the one with the receipts 🧾
bufferControlOwner OBJECT-TYPE SYNTAX OwnerString ACCESS read-write STATUS mandatory DESCRIPTION "The entity that configured this entry and is therefore using the resources assigned to it." ::= { bufferControlEntry 12 }
**bufferControlStatus** 🚦 The last column, and it's the row's overall status. It's read-write, so it's how you manage the entry's life cycle, aka the whole vibe check for this buffer 💜
bufferControlStatus OBJECT-TYPE SYNTAX EntryStatus ACCESS read-write STATUS mandatory DESCRIPTION "The status of this buffer Control Entry." ::= { bufferControlEntry 13 }
Okay so we're back in the MIB code, and this part is the packet capture buffer plus the start of the Event Group 📦✨ Code can't be cute, so every line below is copied exactly as the spec has it 💅
captureBufferTable OBJECT-TYPE SYNTAX SEQUENCE OF CaptureBufferEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of packets captured off of a channel." ::= { capture 2 }
captureBufferEntry OBJECT-TYPE SYNTAX CaptureBufferEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A packet captured off of an attached network. As an example, an instance of the captureBufferPacketData object might be named captureBufferPacketData.3.1783" INDEX { captureBufferControlIndex, captureBufferIndex } ::= { captureBufferTable 1 }
CaptureBufferEntry ::= SEQUENCE { captureBufferControlIndex INTEGER (1..65535), captureBufferIndex INTEGER (1..2147483647), captureBufferPacketID INTEGER, captureBufferPacketData OCTET STRING, captureBufferPacketLength INTEGER, captureBufferPacketTime INTEGER, captureBufferPacketStatus INTEGER }
captureBufferControlIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "The index of the bufferControlEntry with which this packet is associated." ::= { captureBufferEntry 1 }
captureBufferIndex OBJECT-TYPE SYNTAX INTEGER (1..2147483647) ACCESS read-only STATUS mandatory DESCRIPTION "An index that uniquely identifies an entry in the captureBuffer table associated with a particular bufferControlEntry. This index will start at 1 and increase by one for each new packet added with the same captureBufferControlIndex.
Should this value reach 2147483647, the next packet added with the same captureBufferControlIndex shall cause this value to wrap around to 1." ::= { captureBufferEntry 2 }
captureBufferPacketID OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "An index that describes the order of packets that are received on a particular interface. The packetID of a packet captured on an interface is defined to be greater than the packetID's of all packets captured previously on the same interface. As the captureBufferPacketID object has a maximum positive value of 2^31 - 1, any captureBufferPacketID object shall have the value of the associated packet's packetID mod 2^31." ::= { captureBufferEntry 3 }
captureBufferPacketData OBJECT-TYPE SYNTAX OCTET STRING ACCESS read-only STATUS mandatory DESCRIPTION "The data inside the packet, starting at the beginning of the packet plus any offset specified in the associated bufferControlDownloadOffset, including any link level headers. The length of the data in this object is the minimum of the length of the captured packet minus the offset, the length of the associated bufferControlCaptureSliceSize minus the offset, and the associated bufferControlDownloadSliceSize. If this minimum is less than zero, this object shall have a length of zero." ::= { captureBufferEntry 4 }
captureBufferPacketLength OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "The actual length (off the wire) of the packet stored in this entry, including FCS octets." ::= { captureBufferEntry 5 }
captureBufferPacketTime OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "The number of milliseconds that had passed since this capture buffer was first turned on when this packet was captured." ::= { captureBufferEntry 6 }
captureBufferPacketStatus OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "A value which indicates the error status of this packet.
The value of this object is defined in the same way as filterPktStatus. The value is a sum. This sum initially takes the value zero. Then, for each error, E, that has been discovered in this packet, 2 raised to a value representing E is added to the sum.
The errors defined for a packet captured off of an Ethernet interface are as follows:
bit # Error 0 Packet is longer than 1518 octets 1 Packet is shorter than 64 octets 2 Packet experienced a CRC or Alignment error 3 First packet in this capture buffer after it was detected that some packets were not processed correctly. 4 Packet's order in buffer is only approximate (May only be set for packets sent from the probe)
For example, an Ethernet fragment would have a value of 6 (2^1 + 2^2).
As this MIB is expanded to new media types, this object will have other media-specific errors defined." ::= { captureBufferEntry 7 }
-- The Event Group
-- Implementation of the Event group is optional. -- -- The Event group controls the generation and notification -- of events from this device. Each entry in the eventTable -- describes the parameters of the event that can be -- triggered. Each event entry is fired by an associated -- condition located elsewhere in the MIB. An event entry -- may also be associated- with a function elsewhere in the -- MIB that will be executed when the event is generated. For -- example, a channel may be turned on or off by the firing -- of an event. -- -- Each eventEntry may optionally specify that a log entry -- be created on its behalf whenever the event occurs. -- Each entry may also specify that notification should -- occur by way of SNMP trap messages. In this case, the -- community for the trap message is given in the associated -- eventCommunity object. The enterprise and specific trap -- fields of the trap are determined by the condition that -- triggered the event. Two traps are defined: risingAlarm -- and fallingAlarm. If the eventTable is triggered by a -- condition specified elsewhere, the enterprise and -- specific trap fields must be specified for traps -- generated for that condition.
eventTable OBJECT-TYPE SYNTAX SEQUENCE OF EventEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of events to be generated." ::= { event 1 }
eventEntry OBJECT-TYPE SYNTAX EventEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A set of parameters that describe an event to be generated when certain conditions are met. As an example, an instance of the eventLastTimeSent object might be named eventLastTimeSent.6" INDEX { eventIndex } ::= { eventTable 1 }
EventEntry ::= SEQUENCE { eventIndex INTEGER (1..65535), eventDescription DisplayString (SIZE (0..127)), eventType INTEGER, eventCommunity OCTET STRING (SIZE (0..127)), eventLastTimeSent TimeTicks, eventOwner OwnerString, eventStatus EntryStatus
}
eventIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "An index that uniquely identifies an entry in the event table. Each such entry defines one event that is to be generated when the appropriate conditions occur." ::= { eventEntry 1 }
eventDescription OBJECT-TYPE SYNTAX DisplayString (SIZE (0..127)) ACCESS read-write STATUS mandatory DESCRIPTION "A comment describing this event entry." ::= { eventEntry 2 }
eventType OBJECT-TYPE SYNTAX INTEGER { none(1), log(2), snmp-trap(3), -- send an SNMP trap log-and-trap(4) } ACCESS read-write STATUS mandatory DESCRIPTION "The type of notification that the probe will make about this event. In the case of log, an entry is made in the log table for each event. In the case of snmp-trap, an SNMP trap is sent to one or more management stations." ::= { eventEntry 3 }
eventCommunity OBJECT-TYPE SYNTAX OCTET STRING (SIZE (0..127)) ACCESS read-write STATUS mandatory DESCRIPTION "If an SNMP trap is to be sent, it will be sent to the SNMP community specified by this octet string. In the future this table will be extended to include the party security mechanism. This object shall be set to a string of length zero if it is intended that that mechanism be used to specify the destination of the trap." ::= { eventEntry 4 }
eventLastTimeSent OBJECT-TYPE SYNTAX TimeTicks ACCESS read-only STATUS mandatory DESCRIPTION "The value of sysUpTime at the time this event entry last generated an event. If this entry has not generated any events, this value will be zero." ::= { eventEntry 5 }
eventOwner OBJECT-TYPE SYNTAX OwnerString ACCESS read-write STATUS mandatory DESCRIPTION "The entity that configured this entry and is therefore using the resources assigned to it.
If this object contains a string starting with 'monitor' and has associated entries in the log table, all connected management stations should retrieve those log entries, as they may have significance to all management stations connected to this device" ::= { eventEntry 6 }
eventStatus OBJECT-TYPE SYNTAX EntryStatus ACCESS read-write STATUS mandatory DESCRIPTION "The status of this event entry.
If this object is not equal to valid(1), all associated log entries shall be deleted by the agent." ::= { eventEntry 7 }
-- logTable OBJECT-TYPE SYNTAX SEQUENCE OF LogEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A list of events that have been logged." ::= { event 2 }
logEntry OBJECT-TYPE SYNTAX LogEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A set of data describing an event that has been logged. For example, an instance of the logDescription object might be named logDescription.6.47" INDEX { logEventIndex, logIndex } ::= { logTable 1 }
LogEntry ::= SEQUENCE { logEventIndex INTEGER (1..65535), logIndex INTEGER (1..2147483647), logTime TimeTicks, logDescription DisplayString (SIZE (0..255)) }
logEventIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only STATUS mandatory DESCRIPTION "The event entry that generated this log entry. The log identified by a particular value of this index is associated with the same eventEntry as identified by the same value of eventIndex." ::= { logEntry 1 }
logIndex OBJECT-TYPE SYNTAX INTEGER (1..2147483647) ACCESS read-only STATUS mandatory DESCRIPTION "An index that uniquely identifies an entry in the log table amongst those generated by the same eventEntries. These indexes are assigned beginning with 1 and increase by one with each new log entry. The association between values of logIndex and logEntries is fixed for the lifetime of each logEntry. The agent may choose to delete the oldest instances of logEntry as required because of lack of memory. It is an implementation-specific matter as to when this deletion may occur." ::= { logEntry 2 }
logTime OBJECT-TYPE SYNTAX TimeTicks ACCESS read-only STATUS mandatory DESCRIPTION "The value of sysUpTime when this log entry was created." ::= { logEntry 3 }
logDescription OBJECT-TYPE SYNTAX DisplayString (SIZE (0..255)) ACCESS read-only STATUS mandatory DESCRIPTION "An implementation dependent description of the event that activated this log entry." ::= { logEntry 4 }
-- These definitions use the TRAP-TYPE macro as -- defined in RFC 1215 [10]
-- Remote Network Monitoring Traps
risingAlarm TRAP-TYPE ENTERPRISE rmon VARIABLES { alarmIndex, alarmVariable, alarmSampleType, alarmValue, alarmRisingThreshold } DESCRIPTION "The SNMP trap that is generated when an alarm entry crosses its rising threshold and generates an event that is configured for sending SNMP traps." ::= 1
fallingAlarm TRAP-TYPE ENTERPRISE rmon VARIABLES { alarmIndex, alarmVariable, alarmSampleType, alarmValue, alarmFallingThreshold } DESCRIPTION "The SNMP trap that is generated when an alarm entry crosses its falling threshold and generates an event that is configured for sending SNMP traps."
::= 2
END
# 6. Acknowledgments ✨
Big shoutout 🫶 this document was put together by the IETF Remote Network Monitoring Working Group, and honestly they absolutely earned it 🌸
# 7. References 📚
[1] Cerf, V., "IAB Recommendations for the Development of Internet Network Management Standards", RFC 1052, NRI, April 1988.
[2] Cerf, V., "Report of the Second Ad Hoc Network Management Review Group", RFC 1109, NRI, August 1989.
[3] Rose M., and K. McCloghrie, "Structure and Identification of Management Information for TCP/IP-based internets", STD 16, RFC 1155, Performance Systems International, Hughes LAN Systems, May 1990.
[4] McCloghrie K., and M. Rose, Editors, "Management Information Base for Network Management of TCP/IP-based internets", STD 17, RFC 1213, Performance Systems International, March 1991.
[5] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple Network Management Protocol", STD 15, RFC 1157, SNMP Research, Performance Systems International, Performance Systems International, MIT Laboratory for Computer Science, May 1990.
[6] McCloghrie, K., and F. Kastenholz, "Evolution of the Interfaces Group of MIB-II", RFC 1573, Hughes LAN Systems, FTP Software, January 1994.
[7] Information processing systems - Open Systems Interconnection - Specification of Abstract Syntax Notation One (ASN.1), International Organization for Standardization. International Standard 8824, (December, 1987).
[8] Information processing systems - Open Systems Interconnection - Specification of Basic Encoding Rules for Abstract Notation One (ASN.1), International Organization for Standardization. International Standard 8825, (December, 1987).
[9] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions", RFC 1212, Performance Systems International, Hughes LAN Systems, March 1991.
[10] Rose, M., Editor, "A Convention for Defining Traps for use with the SNMP", RFC 1215, Performance Systems International, March 1991.
# 8. Security Considerations 😱🔒
Security issues are not discussed in this memo. Yes, you read that right, bestie 💀 This doc does not cover security at all, so please don't assume any protection is baked in just because it's an RFC. Take that seriously. 🚨
# 9. Author's Address 💌
Steven Waldbusser Carnegie Mellon University 5000 Forbes Ave. Pittsburgh, PA 15213
EMail: waldbusser@cmu.edu
# 10. Appendix: Changes from RFC 1271 🦋
Okay, the good news is that the RMON MIB hasn't been significantly changed since RFC 1271 was issued. 🌈 The glow-up was mostly small stuff, but there were a couple of object-level changes worth knowing about:
1. A new status bit has been defined for the `captureBufferPacketStatus` object, indicating that the packet order within the capture buffer may not be identical to the packet order as received off the wire. This bit may only be used for packets transmitted by the probe. Older NMS applications can safely ignore this status bit, which might be used by newer agents. 💅
2. The `packetMatch` trap has been removed. ✂️ This trap was never actually 'approved' and was not added to this document along with the `risingAlarm` and `fallingAlarm` traps. The `packetMatch` trap could not be throttled, which could cause disruption of normal network traffic under some circumstances. An NMS should configure a `risingAlarm` threshold on the appropriate `channelMatches` instance if a trap is desired for a `packetMatch` event. Note that logging of `packetMatch` events is still supported--only trap generation for such events has been removed. 🙈
In addition, several clarifications to individual object definitions have been added to assist agent and NMS implementors, and they're giving main character energy ✨
- global definition of "good packets" and "bad packets"
- more detailed text governing conceptual row creation and modification
- instructions for probes relating to interface changes and disruptions
- clarification of some ethernet counter definitions
- recommended formula for calculating network utilization
- clarification of channel and captureBuffer behavior for some unusual conditions
- examples of proper instance naming for each table
That's the whole tea, bestie. 🫶💜
📦 where this page comes from
- ietf: rfc1757 1995-02
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms