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RFC 2819

 
 
 

Remote Network Monitoring Management Information Base

Part 2 of 4, p. 12 to 44
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5.  Definitions

 RMON-MIB DEFINITIONS ::= BEGIN

     IMPORTS
         MODULE-IDENTITY, OBJECT-TYPE, OBJECT-IDENTITY,
         NOTIFICATION-TYPE, mib-2, Counter32,
         Integer32, TimeTicks                   FROM SNMPv2-SMI

         TEXTUAL-CONVENTION, DisplayString      FROM SNMPv2-TC

         MODULE-COMPLIANCE, OBJECT-GROUP,
         NOTIFICATION-GROUP                     FROM SNMPv2-CONF;


 --  Remote Network Monitoring MIB

 rmonMibModule MODULE-IDENTITY
     LAST-UPDATED "200005110000Z"  -- 11 May, 2000
     ORGANIZATION "IETF RMON MIB Working Group"
     CONTACT-INFO
         "Steve Waldbusser
         Phone: +1-650-948-6500
         Fax:   +1-650-745-0671
         Email: waldbusser@nextbeacon.com"
     DESCRIPTION
         "Remote network monitoring devices, often called
         monitors or probes, are instruments that exist for
         the purpose of managing a network. This MIB defines
         objects for managing remote network monitoring devices."

     REVISION "200005110000Z"    -- 11 May, 2000
     DESCRIPTION
         "Reformatted into SMIv2 format.

         This version published as RFC 2819."

     REVISION "199502010000Z" -- 1 Feb, 1995
     DESCRIPTION
         "Bug fixes, clarifications and minor changes based on
         implementation experience, published as RFC1757 [18].

         Two changes were made to object definitions:

         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

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         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:

         - 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"

     REVISION "199111010000Z"    -- 1 Nov, 1991
     DESCRIPTION
         "The original version of this MIB, published as RFC1271."
     ::= { rmonConformance 8 }

     rmon    OBJECT IDENTIFIER ::= { mib-2 16 }


     -- textual conventions

 OwnerString ::= TEXTUAL-CONVENTION
     STATUS current

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     DESCRIPTION
         "This data type is used to model an administratively
         assigned name of the owner of a resource. Implementations
         must accept values composed of well-formed NVT ASCII
         sequences. In addition, implementations should accept
         values composed of well-formed UTF-8 sequences.

         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."
     SYNTAX OCTET STRING (SIZE (0..127))

 EntryStatus ::= TEXTUAL-CONVENTION
     STATUS current
     DESCRIPTION
         "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

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         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 multiple 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:

              To:       valid  createRequest  underCreation  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.

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         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 exercise these additional state transitions."
     SYNTAX INTEGER {
                valid(1),
                createRequest(2),
                underCreation(3),
                invalid(4)
            }

     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 }
     rmonConformance   OBJECT IDENTIFIER ::= { rmon 20 }

 -- The Ethernet Statistics Group
 --
 -- Implementation of the Ethernet Statistics group is optional.
 -- Consult the MODULE-COMPLIANCE macro for the authoritative
 -- conformance information for this MIB.
 --
 -- 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.

 etherStatsTable OBJECT-TYPE
     SYNTAX     SEQUENCE OF EtherStatsEntry
     MAX-ACCESS not-accessible
     STATUS     current
     DESCRIPTION
         "A list of Ethernet statistics entries."
     ::= { statistics 1 }

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 etherStatsEntry OBJECT-TYPE
     SYNTAX     EtherStatsEntry
     MAX-ACCESS not-accessible
     STATUS     current
     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                    Integer32,
     etherStatsDataSource               OBJECT IDENTIFIER,
     etherStatsDropEvents               Counter32,
     etherStatsOctets                   Counter32,
     etherStatsPkts                     Counter32,
     etherStatsBroadcastPkts            Counter32,
     etherStatsMulticastPkts            Counter32,
     etherStatsCRCAlignErrors           Counter32,
     etherStatsUndersizePkts            Counter32,
     etherStatsOversizePkts             Counter32,
     etherStatsFragments                Counter32,
     etherStatsJabbers                  Counter32,
     etherStatsCollisions               Counter32,
     etherStatsPkts64Octets             Counter32,
     etherStatsPkts65to127Octets        Counter32,
     etherStatsPkts128to255Octets       Counter32,
     etherStatsPkts256to511Octets       Counter32,
     etherStatsPkts512to1023Octets      Counter32,
     etherStatsPkts1024to1518Octets     Counter32,
     etherStatsOwner                    OwnerString,
     etherStatsStatus                   EntryStatus
 }

 etherStatsIndex OBJECT-TYPE
     SYNTAX     Integer32 (1..65535)
     MAX-ACCESS read-only
     STATUS     current
     DESCRIPTION
         "The value of this object uniquely identifies this
         etherStats entry."
     ::= { etherStatsEntry 1 }

 etherStatsDataSource OBJECT-TYPE
     SYNTAX     OBJECT IDENTIFIER
     MAX-ACCESS read-create
     STATUS     current

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     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 2233 [17], 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 }

 etherStatsDropEvents OBJECT-TYPE
     SYNTAX     Counter32
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Octets"
     MAX-ACCESS read-only
     STATUS     current
     DESCRIPTION
         "The total number of octets of data (including
         those in bad packets) received on the
         network (excluding framing bits but including
         FCS octets).

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         This object can be used as a reasonable estimate of
         10-Megabit 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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     DESCRIPTION
         "The total number of packets (including bad packets,
         broadcast packets, and multicast packets) received."
     ::= { etherStatsEntry 5 }

 etherStatsBroadcastPkts OBJECT-TYPE
     SYNTAX     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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

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         address."
     ::= { etherStatsEntry 7 }

 etherStatsCRCAlignErrors OBJECT-TYPE
     SYNTAX     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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 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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     DESCRIPTION

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         "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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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 }

 etherStatsCollisions OBJECT-TYPE
     SYNTAX     Counter32
     UNITS      "Collisions"
     MAX-ACCESS read-only
     STATUS     current
     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

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         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."
     ::= { etherStatsEntry 13 }

 etherStatsPkts64Octets OBJECT-TYPE
     SYNTAX     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only

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     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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
     MAX-ACCESS read-create
     STATUS     current

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     DESCRIPTION
         "The entity that configured this entry and is therefore
         using the resources assigned to it."
     ::= { etherStatsEntry 20 }

 etherStatsStatus OBJECT-TYPE
     SYNTAX     EntryStatus
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "The status of this etherStats entry."
     ::= { etherStatsEntry 21 }

 -- The History Control Group

 -- Implementation of the History Control group is optional.
 -- Consult the MODULE-COMPLIANCE macro for the authoritative
 -- conformance information for this MIB.
 --
 -- 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
     MAX-ACCESS not-accessible

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     STATUS     current
     DESCRIPTION
         "A list of history control entries."
     ::= { history 1 }

 historyControlEntry OBJECT-TYPE
     SYNTAX     HistoryControlEntry
     MAX-ACCESS not-accessible
     STATUS     current
     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             Integer32,
     historyControlDataSource        OBJECT IDENTIFIER,
     historyControlBucketsRequested  Integer32,
     historyControlBucketsGranted    Integer32,
     historyControlInterval          Integer32,
     historyControlOwner             OwnerString,
     historyControlStatus            EntryStatus
 }

 historyControlIndex OBJECT-TYPE
     SYNTAX     Integer32 (1..65535)
     MAX-ACCESS read-only
     STATUS     current
     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
     MAX-ACCESS read-create
     STATUS     current
     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

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         a particular interface, this object shall identify
         the instance of the ifIndex object, defined
         in  RFC 2233 [17], 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     Integer32 (1..65535)
     MAX-ACCESS read-create
     STATUS     current
     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     Integer32 (1..65535)
     MAX-ACCESS read-only
     STATUS     current
     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.

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         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 }

 historyControlInterval OBJECT-TYPE
     SYNTAX     Integer32 (1..3600)
     UNITS      "Seconds"
     MAX-ACCESS read-create
     STATUS     current
     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

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         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 }

 historyControlOwner OBJECT-TYPE
     SYNTAX     OwnerString
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "The entity that configured this entry and is therefore
         using the resources assigned to it."
     ::= { historyControlEntry 6 }

 historyControlStatus OBJECT-TYPE
     SYNTAX     EntryStatus
     MAX-ACCESS read-create
     STATUS     current
     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 }

 -- The Ethernet History Group

 -- Implementation of the Ethernet History group is optional.
 -- Consult the MODULE-COMPLIANCE macro for the authoritative
 -- conformance information for this MIB.
 --
 -- 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

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 -- 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
     MAX-ACCESS not-accessible
     STATUS     current
     DESCRIPTION
         "A list of Ethernet history entries."
     ::= { history 2 }

 etherHistoryEntry OBJECT-TYPE
     SYNTAX     EtherHistoryEntry
     MAX-ACCESS not-accessible
     STATUS     current
     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                 Integer32,
     etherHistorySampleIndex           Integer32,
     etherHistoryIntervalStart         TimeTicks,
     etherHistoryDropEvents            Counter32,
     etherHistoryOctets                Counter32,
     etherHistoryPkts                  Counter32,
     etherHistoryBroadcastPkts         Counter32,
     etherHistoryMulticastPkts         Counter32,
     etherHistoryCRCAlignErrors        Counter32,
     etherHistoryUndersizePkts         Counter32,
     etherHistoryOversizePkts          Counter32,
     etherHistoryFragments             Counter32,
     etherHistoryJabbers               Counter32,
     etherHistoryCollisions            Counter32,
     etherHistoryUtilization           Integer32
 }

 etherHistoryIndex OBJECT-TYPE
     SYNTAX     Integer32 (1..65535)
     MAX-ACCESS read-only

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     STATUS     current
     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     Integer32 (1..2147483647)
     MAX-ACCESS read-only
     STATUS     current
     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 }

 etherHistoryIntervalStart OBJECT-TYPE
     SYNTAX     TimeTicks
     MAX-ACCESS read-only
     STATUS     current
     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 }

 etherHistoryDropEvents OBJECT-TYPE
     SYNTAX     Counter32
     MAX-ACCESS read-only
     STATUS     current
     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

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         detected."
     ::= { etherHistoryEntry 4 }

 etherHistoryOctets OBJECT-TYPE
     SYNTAX     Counter32
     UNITS      "Octets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     DESCRIPTION
         "The number of packets (including bad packets)
         received during this sampling interval."
     ::= { etherHistoryEntry 6 }

 etherHistoryBroadcastPkts OBJECT-TYPE
     SYNTAX     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     DESCRIPTION
         "The number of good packets received during this
         sampling interval that were directed to the
         broadcast address."
     ::= { etherHistoryEntry 7 }

 etherHistoryMulticastPkts OBJECT-TYPE
     SYNTAX     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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 }

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 etherHistoryCRCAlignErrors OBJECT-TYPE
     SYNTAX     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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 OBJECT-TYPE
     SYNTAX     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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

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         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
     SYNTAX     Counter32
     UNITS      "Packets"
     MAX-ACCESS read-only
     STATUS     current
     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     Counter32
     UNITS      "Collisions"
     MAX-ACCESS read-only
     STATUS     current
     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

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         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     Integer32 (0..10000)
     MAX-ACCESS read-only
     STATUS     current
     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.
 -- Consult the MODULE-COMPLIANCE macro for the authoritative
 -- conformance information for this MIB.
 --
 -- 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, Integer32,
 -- Counter32, Counter64, Gauge32, or TimeTicks) may be monitored in
 -- this way.
 --

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 -- 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
     MAX-ACCESS not-accessible
     STATUS     current
     DESCRIPTION
         "A list of alarm entries."
     ::= { alarm 1 }

 alarmEntry OBJECT-TYPE
     SYNTAX     AlarmEntry
     MAX-ACCESS not-accessible
     STATUS     current
     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                    Integer32,
     alarmInterval                 Integer32,
     alarmVariable                 OBJECT IDENTIFIER,
     alarmSampleType               INTEGER,
     alarmValue                    Integer32,
     alarmStartupAlarm             INTEGER,
     alarmRisingThreshold          Integer32,
     alarmFallingThreshold         Integer32,
     alarmRisingEventIndex         Integer32,
     alarmFallingEventIndex        Integer32,
     alarmOwner                    OwnerString,
     alarmStatus                   EntryStatus
 }

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 alarmIndex OBJECT-TYPE
     SYNTAX     Integer32 (1..65535)
     MAX-ACCESS read-only
     STATUS     current
     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     Integer32
     UNITS      "Seconds"
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "The interval in seconds over which the data is
         sampled and compared with the rising and falling
         thresholds.  When setting this 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
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "The object identifier of the particular variable to be
         sampled.  Only variables that resolve to an ASN.1 primitive
         type of INTEGER (INTEGER, Integer32, Counter32, Counter64,
         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

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         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)
                }
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "The method of sampling the selected variable and
         calculating the value to be compared against the
         thresholds.  If the value of this object is
         absoluteValue(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     Integer32
     MAX-ACCESS read-only
     STATUS     current
     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.

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         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 }

 alarmStartupAlarm OBJECT-TYPE
     SYNTAX     INTEGER {
                  risingAlarm(1),
                  fallingAlarm(2),
                  risingOrFallingAlarm(3)
                }
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "The alarm that may be sent when this entry is first
         set to 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     Integer32
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "A threshold for the sampled statistic.  When the current
         sampled value is greater than or equal to this threshold,
         and the value at the last sampling interval was less than
         this threshold, a single event will be generated.
         A single event will also be generated if the first
         sample after this entry becomes 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

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         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     Integer32
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "A threshold for the sampled statistic.  When the current
         sampled value is less than or equal to this threshold,
         and the value at the last sampling interval was greater than
         this threshold, a single event will be generated.
         A single event will also be generated if the first
         sample after this entry becomes 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     Integer32 (0..65535)
     MAX-ACCESS read-create
     STATUS     current
     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

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         alarmStatus object is equal to valid(1)."
     ::= { alarmEntry 9 }

 alarmFallingEventIndex OBJECT-TYPE
     SYNTAX     Integer32 (0..65535)
     MAX-ACCESS read-create
     STATUS     current
     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
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "The entity that configured this entry and is therefore
         using the resources assigned to it."
     ::= { alarmEntry 11 }

 alarmStatus OBJECT-TYPE
     SYNTAX     EntryStatus
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "The status of this alarm entry."
     ::= { alarmEntry 12 }

 -- The Host Group

 -- Implementation of the Host group is optional.
 -- Consult the MODULE-COMPLIANCE macro for the authoritative
 -- conformance information for this MIB.
 --
 -- 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

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 -- 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

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 -- 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
     MAX-ACCESS not-accessible
     STATUS     current
     DESCRIPTION
         "A list of host table control entries."
     ::= { hosts 1 }

 hostControlEntry OBJECT-TYPE
     SYNTAX     HostControlEntry
     MAX-ACCESS not-accessible
     STATUS     current
     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            Integer32,
     hostControlDataSource       OBJECT IDENTIFIER,
     hostControlTableSize        Integer32,
     hostControlLastDeleteTime   TimeTicks,
     hostControlOwner            OwnerString,
     hostControlStatus           EntryStatus
 }

 hostControlIndex OBJECT-TYPE
     SYNTAX     Integer32 (1..65535)
     MAX-ACCESS read-only
     STATUS     current
     DESCRIPTION
         "An index that uniquely identifies an entry in the

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         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 }

 hostControlDataSource OBJECT-TYPE
     SYNTAX     OBJECT IDENTIFIER
     MAX-ACCESS read-create
     STATUS     current
     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 2233 [17], 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 }

 hostControlTableSize OBJECT-TYPE
     SYNTAX     Integer32
     MAX-ACCESS read-only
     STATUS     current
     DESCRIPTION
         "The number of hostEntries in the hostTable and the
         hostTimeTable associated with this hostControlEntry."
     ::= { hostControlEntry 3 }

 hostControlLastDeleteTime OBJECT-TYPE
     SYNTAX     TimeTicks
     MAX-ACCESS read-only

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     STATUS     current
     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
     MAX-ACCESS read-create
     STATUS     current
     DESCRIPTION
         "The entity that configured this entry and is therefore
         using the resources assigned to it."
     ::= { hostControlEntry 5 }

 hostControlStatus OBJECT-TYPE
     SYNTAX     EntryStatus
     MAX-ACCESS read-create
     STATUS     current
     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 }

 hostTable OBJECT-TYPE
     SYNTAX     SEQUENCE OF HostEntry
     MAX-ACCESS not-accessible
     STATUS     current
     DESCRIPTION
         "A list of host entries."
     ::= { hosts 2 }

 hostEntry OBJECT-TYPE
     SYNTAX     HostEntry
     MAX-ACCESS not-accessible
     STATUS     current
     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 }


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