rfc1757.txt

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Waldbusser                                                     [Page 21]

RFC 1757             Remote Network Monitoring MIB         February 1995


              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



Waldbusser                                                     [Page 22]

RFC 1757             Remote Network Monitoring MIB         February 1995


              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



Waldbusser                                                     [Page 23]

RFC 1757             Remote Network Monitoring MIB         February 1995


                  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



Waldbusser                                                     [Page 24]

RFC 1757             Remote Network Monitoring MIB         February 1995


                  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 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



Waldbusser                                                     [Page 25]

RFC 1757             Remote Network Monitoring MIB         February 1995


                  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
              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 }


          -- 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.
          --



Waldbusser                                                     [Page 26]

RFC 1757             Remote Network Monitoring MIB         February 1995


          etherHistoryTable OBJECT-TYPE
              SYNTAX SEQUENCE OF EtherHistoryEntry
              ACCESS not-accessible
              STATUS mandatory
              DESCRIPTION