RFC1271

Network Working Group S. Waldbusser Request for Comments: 1271 Carnegie Mellon University

                                                       November 1991

     Remote Network Monitoring Management Information Base

Status of this Memo

This memo is an extension to the SNMP MIB. This RFC specifies an IAB standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited.

5.1 Resource Sharing Among Multiple Management Stations .. 8

Abstract

This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in TCP/IP-based internets. In particular, it defines objects for managing remote network monitoring devices.

The Network Management Framework

The Internet-standard Network Management Framework consists of three components. They are:

  RFC 1155 which defines the SMI, the mechanisms used for describing
  and naming objects for the purpose of management.  RFC 1212
  defines a more concise description mechanism, which is wholly
  consistent with the SMI.

  RFC 1156 which defines MIB-I, the core set of managed objects for
  the Internet suite of protocols.  RFC 1213, defines MIB-II, an
  evolution of MIB-I based on implementation experience and new
  operational requirements.

  RFC 1157 which defines the SNMP, the protocol used for network
  access to managed objects.

The Framework permits new objects to be defined for the purpose of experimentation and evaluation.

Objects

Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the subset of Abstract Syntax Notation One (ASN.1) [7] defined in the SMI. In particular, each object has a name, a syntax, and an encoding. The name is an object identifier, an administratively assigned name, which specifies an object type. The object type together with an object instance serves to uniquely identify a specific instantiation of the object. For human convenience, we often use a textual string, termed the OBJECT DESCRIPTOR, to also refer to the object type.

The syntax of an object type defines the abstract data structure corresponding to that object type. The ASN.1 language is used for this purpose. However, the SMI [3] purposely restricts the ASN.1 constructs which may be used. These restrictions are explicitly made for simplicity.

The encoding of an object type is simply how that object type

is represented using the object type's syntax. Implicitly tied to the notion of an object type's syntax and encoding is how the object type is represented when being transmitted on the network.

The SMI specifies the use of the basic encoding rules of ASN.1 [8], subject to the additional requirements imposed by the SNMP.

Format of Definitions

Section 6 contains the specification of all object types contained in this MIB module. The object types are defined using the conventions defined in the SMI, as amended by the extensions specified in [9,10].

Overview

Remote network monitoring devices are instruments that exist for the purpose of managing a network. Often these remote probes are stand-alone devices and devote significant internal resources for the sole purpose of managing a network. An organization may employ many of these devices, one per network segment, to manage its internet. In addition, these devices may be used for a network management service provider to access a client network, often geographically remote.

While many of the objects in this document are suitable for the management of any type of network, there are some which are specific to managing Ethernet networks. The design of this MIB allows similar objects to be defined for other network types. It is intended that future versions of this document will define extensions for other network types such as Token Ring and FDDI.

Remote Network Management Goals

          o Offline Operation
              There are sometimes conditions when a management
              station will not be in constant contact with its
              remote monitoring devices.  This is sometimes by
              design in an attempt to lower communications costs
              (especially when communicating over a WAN or
              dialup link), or by accident as network failures
              affect the communications between the management
              station and the probe.

              For this reason, this MIB allows a probe to be
              configured to perform diagnostics and to collect
              statistics continuously, even when communication with
              the management station may not be possible or

              efficient.  The probe may then attempt to notify
              the management station when an exceptional condition
              occurs.  Thus, even in circumstances where
              communication between management station and probe is
              not continuous, fault, performance, and configuration
              information may be continuously accumulated and
              communicated to the management station conveniently
              and efficiently.

          o Preemptive Monitoring
              Given the resources available on the monitor, it
              is potentially helpful for it continuously to run
              diagnostics and to log network performance.  The
              monitor is always available at the onset of any
              failure.  It can notify the management station of the
              failure and can store historical statistical
              information about the failure.  This historical
              information can be played back by the management
              station in an attempt to perform further diagnosis
              into the cause of the problem.

          o Problem Detection and Reporting
              The monitor can be configured to recognize
              conditions, most notably error conditions, and
              continuously to check for them.  When one of these
              conditions occurs, the event may be logged, and
              management stations may be notified in a number of
              ways.

          o Value Added Data
              Because a remote monitoring device represents a
              network resource dedicated exclusively to network
              management functions, and because it is located
              directly on the monitored portion of the network, the
              remote network monitoring device has the opportunity
              to add significant value to the data it collects.
              For instance, by highlighting those hosts on the
              network that generate the most traffic or errors, the
              probe can give the management station precisely the
              information it needs to solve a class of problems.

          o Multiple Managers
              An organization may have multiple management stations
              for different units of the organization, for different
              functions (e.g. engineering and operations), and in an
              attempt to provide disaster recovery.  Because
              environments with multiple management stations are
              common, the remote network monitoring device has to

              deal with more than own management station,
              potentially using its resources concurrently.

Textual Conventions

Two new data types are introduced as a textual convention in this MIB document. These textual conventions enhance the readability of the specification and can ease comparison with other specifications if appropriate. It should be noted that the introduction of the these textual conventions has no effect on either the syntax nor the semantics of any managed objects. The use of these is merely an artifact of the explanatory method used. Objects defined in terms of one of these methods are always encoded by means of the rules that define the primitive type. Hence, no changes to the SMI or the SNMP are necessary to accommodate these textual conventions which are adopted merely for the convenience of readers and writers in pursuit of the elusive goal of clear, concise, and unambiguous MIB documents.

The new data types are: OwnerString and EntryStatus.

Structure of MIB

The objects are arranged into the following groups:

              - statistics

              - history

              - alarm

              - host

              - hostTopN

              - matrix

              - filter

              - packet capture

              - event

These groups are the basic unit of conformance. If a remote monitoring device implements a group, then it must implement all objects in that group. For example, a managed agent that implements the host group must implement the hostControlTable, the hostTable and the hostTimeTable.

All groups in this MIB are optional. Implementations of this MIB must also implement the system and interfaces group of MIB-II [6]. MIB-II may also mandate the implementation of additional groups.

These groups are defined to provide a means of assigning object identifiers, and to provide a method for managed agents to know which objects they must implement.

The Statistics Group

The statistics group contains statistics measured by the probe for each monitored interface on this device. This group currently consists of the etherStatsTable but in the future will contain tables for other media types including Token Ring and FDDI.

The History Group

The history group records periodic statistical samples from a network and stores them for later retrieval. This group currently consists of the historyControlTable and the etherHistoryTable. In future versions of the MIB, this group may contain tables for other media types including Token Ring and FDDI.

The Alarm Group

The alarm group periodically takes statistical samples from variables in the probe and compares them to previously configured thresholds. If the monitored variable crosses a threshold, an event is generated. A hysteresis mechanism is implemented to limit the generation of alarms. This group consists of the alarmTable and requires the implementation of the event group.

The Host Group

The host group contains statistics associated with each host discovered on the network. This group discovers hosts on the network by keeping a list of source and destination MAC Addresses seen in good packets promiscuously received from the network. This group consists of the hostControlTable, the hostTable, and the hostTimeTable.

The HostTopN Group

The hostTopN 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. This group consists of the hostTopNControlTable and the hostTopNTable, and requires the implementation of the host group.

The Matrix Group

The matrix group stores statistics for conversations between sets of two addresses. As the device detects a new conversation, it creates a new entry in its tables. This group consists of the matrixControlTable, the matrixSDTable and the matrixDSTable.

The Filter Group

The filter group allows packets to be matched by a filter equation. These matched packets form a data stream that may be captured or may generate events. This group consists of the filterTable and the channelTable.

The Packet Capture Group

The Packet Capture group allows packets to be captured after they flow through a channel. This group consists of the bufferControlTable and the captureBufferTable, and requires the implementation of the filter group.

The Event Group

The event group controls the generation and notification of events from this device. This group consists of the eventTable and the logTable.

Control of Remote Network Monitoring Devices

Due to the complex nature of the available functions in these devices, the functions often need user configuration. In many cases, the function requires parameters to be set up for a data collection operation. The operation can proceed only after these parameters are fully set up.

Many functional groups in this MIB have one or more tables in which to set up control parameters, and one or more data tables in which to place the results of the operation. The control tables are typically read-write in nature, while the data tables are typically read-only. Because the parameters in the control table often describe resulting data in the data table, many of the parameters can be modified only when the control entry is invalid. Thus, the method for modifying these parameters is to invalidate the control entry, causing its deletion and the deletion of any associated data entries, and then

create a new control entry with the proper parameters. Deleting the control entry also gives a convenient method for reclaiming the resources used by the associated data.

Some objects in this MIB provide a mechanism to execute an action on the remote monitoring device. These objects may execute an action as a result of a change in the state of the object. For those objects in this MIB, a request to set an object to the same value as it currently holds would thus cause no action to occur.

To facilitate control by multiple managers, resources have to be shared among the managers. These resources are typically the memory and computation resources that a function requires.

Resource Sharing Among Multiple Management Stations

When multiple management stations wish to use functions that compete for a finite amount of resources on a device, a method to facilitate this sharing of resources is required. Potential conflicts include:

          o Two management stations wish to simultaneously use
            resources that together would exceed the capability of
            the device.

          o A management station uses a significant amount of
            resources for a long period of time.

          o A management station uses resources and then crashes,
            forgetting to free the resources so others may
            use them.

A mechanism is provided for each management station initiated function in this MIB to avoid these conflicts and to help resolve them when they occur. Each function has a label identifying the initiator (owner) of the function. This label is set by the initiator to provide for the following possibilities:

          o A management station may recognize resources it owns
            and no longer needs.

          o A network operator can find the management station that
            owns the resource and negotiate for it to be freed.

          o A network operator may decide to unilaterally free
            resources another network operator has reserved.

          o Upon initialization, a management station may recognize
            resources it had reserved in the past.  With this

            information it may free the resources if it no longer
            needs them.

Management stations and probes should support any format of the owner string dictated by the local policy of the organization. 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. This information will help users to share the resources more effectively.

There is often default functionality that the device wishes to set up. The resources associated with this functionality are then owned by the device itself. In this case, the device will set the relevant owner object to a string starting with 'monitor'. Indiscriminate modification of the 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 administrator of the probe, often the network administrator.

When a network management station wishes to utilize a function in a monitor, it is encouraged to first scan the control table of that function to find an instance with similar parameters to share. This is especially true for those 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 management station that owns the instance may indiscriminately modify or delete it.

Row Addition Among Multiple Management Stations

The addition of new rows is achieved using the method described in [9]. In this MIB, rows are often added to a table in order to configure a function. This configuration usually involves parameters that control the operation of the function. The agent must check these parameters to make sure they are appropriate given restrictions defined in this MIB as well as any implementation specific restrictions such as lack of resources. The agent implementor may be confused as to when to check these parameters and when to signal to the management station that the parameters are invalid. There are two opportunities:

          o When the management station sets each parameter object.

          o When the management station sets the entry status object
            to valid.

If the latter is chosen, it would be unclear to the management station which of the several parameters was invalid and caused the

badValue error to be emitted. Thus, wherever possible, the implementor should choose the former as it will provide more information to the management station.

A problem can arise when multiple management stations attempt to set configuration information simultaneously using SNMP. When this involves the addition of a new conceptual row in the same control table, the managers may collide, attempting to create the same entry. To guard against these collisions, each such control entry contains a status object with special semantics that help to arbitrate among the managers. If an attempt is made with the row addition mechanism to create such a status object and that object already exists, an error is returned. When more than one manager simultaneously attempts to create the same conceptual row, only the first will succeed. The others will receive an error.

Definitions

      RFC1271-MIB DEFINITIONS ::= BEGIN

          IMPORTS
              Counter                              FROM RFC1155-SMI
              DisplayString                        FROM RFC1158-MIB
              mib-2                                FROM RFC1213-MIB
              OBJECT-TYPE                          FROM RFC-1212;

      --  This MIB module uses the extended OBJECT-TYPE macro as
      --  defined in [9].

      --  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 to complete a conceptual
          -- row in this table.  Immediately after completing the
          -- create operation, the agent must set this object to
          -- underCreation(3).
          --
          -- 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.

          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 Statistics Group
      --
      -- Implementation of the Statistics group is optional.
      --
      -- The 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
          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."
          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                   INTEGER
      }

      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 [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.

              This object may not be modified if the associated
              etherStatsStatus object is equal to valid(1)."
          ::= { etherStatsEntry 2 }

      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)."
          ::= { etherStatsEntry 4 }

      etherStatsPkts OBJECT-TYPE
          SYNTAX Counter
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The total number of packets (including error 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."
          ::= { 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 }

      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 were not an integral number
              of octets in length or had a bad Frame Check
              Sequence (FCS)."
          ::= { 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 not an
              integral number of octets in length or that had a bad
              Frame Check Sequence (FCS), and were less than 64
              octets in length (excluding framing bits but
              including FCS octets)."
          ::= { 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 were not an
              integral number of octets in length or had
              a bad Frame Check Sequence (FCS)."
          ::= { etherStatsEntry 12 }

      etherStatsCollisions OBJECT-TYPE
          SYNTAX Counter
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The best estimate of the total number of collisions
              on this Ethernet segment."
          ::= { etherStatsEntry 13 }

      etherStatsPkts64Octets OBJECT-TYPE
          SYNTAX Counter
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The total number of packets (including error
              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 error
              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 error
              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 error
              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 error
              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 error
              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 Group

      -- Implementation of the History group is optional.
      --
      -- The history group records periodic statistical samples from
      -- a network and stores them for later retrieval.  The
      -- historyControl table 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.  Currently the only media-
      -- specific table defined is the etherHistoryTable, for
      -- Ethernet networks.
      --
      -- 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 monitor 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."
          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            INTEGER
      }

      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 [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.

              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
              historyControl entry.

              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
              historyControl entry.

              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 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
              historyControl entry.  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 }

      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 }

      -- Ether History table

      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."
          INDEX { etherHistoryIndex , etherHistorySampleIndex }
          ::= { etherHistoryTable 1 }

      EtherHistoryEntry ::= SEQUENCE {
          etherHistoryIndex                 INTEGER (1..65535),
          etherHistorySampleIndex           INTEGER,
          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)
      }

      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
          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 }

      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 }

      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 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 error 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 }

      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 were not an
              integral number of octets in length or had a
              bad Frame Check Sequence (FCS)."
          ::= { etherHistoryEntry 9 }

      etherHistoryUndersizePkts OBJECT-TYPE
          SYNTAX Counter
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The number of packets received during this
              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
              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 Counter
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The total number of packets received during this
              sampling interval that were not an integral
              number of octets in length or that
              had a bad Frame Check Sequence (FCS), and
              were less than 64 octets in length (excluding
              framing bits but including FCS octets)."
          ::= { etherHistoryEntry 12 }

      etherHistoryJabbers OBJECT-TYPE
          SYNTAX Counter
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The number of packets received during this
              interval that were longer than 1518 octets
              (excluding framing bits but including FCS octets),
              and were not an integral number of octets in
              length or had a bad Frame Check Sequence (FCS)."
          ::= { 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 interval."
          ::= { 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
              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."
          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 (1..65535),
          alarmFallingEventIndex        INTEGER (1..65535),
          alarmOwner                    OwnerString,
          alarmStatus                   INTEGER
      }

      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 given to ensure that the variable being
              monitored will not exceed 2^31 - 1 and roll
              over the alarmValue object during the 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.  The value during the current sampling period
              is not made available until the period is completed."
          ::= { alarmEntry 5 }

      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 }

      -- 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 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 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."
          INDEX { hostControlIndex }
          ::= { hostControlTable 1 }

      HostControlEntry ::= SEQUENCE {
          hostControlIndex            INTEGER (1..65535),
          hostControlDataSource       OBJECT IDENTIFIER,
          hostControlTableSize        INTEGER,
          hostControlLastDeleteTime   TimeTicks,
          hostControlOwner            OwnerString,
          hostControlStatus           INTEGER
      }

      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 }

      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 [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.

              This object may not be modified if the associated
              hostControlStatus object is equal to valid(1)."
          ::= { hostControlEntry 2 }

      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 }

      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."
          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
      }

      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 }

      hostInPkts OBJECT-TYPE
          SYNTAX Counter
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The number of packets without errors 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 errors 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 packets that contained errors."
          ::= { 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 packets that contained errors."
          ::= { hostEntry 7 }

      hostOutErrors OBJECT-TYPE
          SYNTAX Counter
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The number of error 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 }

      -- 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."
          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 }

      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 packets without errors 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 packets including errors 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 packets that contained errors."
          ::= { 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 packets that contained errors."
          ::= { hostTimeEntry 7 }

      hostTimeOutErrors OBJECT-TYPE
          SYNTAX Counter
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The number of error 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."
          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          INTEGER
      }

      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 hostTopNTable.  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."
          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 }

      -- 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."
          INDEX { matrixControlIndex }
          ::= { matrixControlTable 1 }

      MatrixControlEntry ::= SEQUENCE {
          matrixControlIndex           INTEGER (1..65535),
          matrixControlDataSource      OBJECT IDENTIFIER,
          matrixControlTableSize       INTEGER,
          matrixControlLastDeleteTime  TimeTicks,
          matrixControlOwner           OwnerString,
          matrixControlStatus          INTEGER
      }

      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 [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.

              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."
          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 error 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 error 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 address on a particular interface."
          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 error 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 error packets transmitted from
              the source address to the destination address."
          ::= { matrixDSEntry 6 }

      -- 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.
      --
      -- 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."
          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                INTEGER

      }

      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 }

      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.

              This object may not be modified if the associated
              filterStatus object is equal to valid(1)."
          ::= { filterEntry 4 }

      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 }

      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 }

      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.

              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
              object, filterPktStatus 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 }

      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 }

      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 }

      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 }

      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."
          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                INTEGER
      }

      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."
          ::= { 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 [4,6].  The filters in
              this group are applied to all packets on the local
              network segment attached to the identified
              interface.

              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.

              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 }

      -- 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."
          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               INTEGER
      }

      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 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 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 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 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 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 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 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 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 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 OBJECT-TYPE
          SYNTAX INTEGER
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
              "The number of packets currently in this captureBuffer."
          ::= { bufferControlEntry 10 }

      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 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 OBJECT-TYPE
          SYNTAX EntryStatus
          ACCESS read-write
          STATUS mandatory
          DESCRIPTION
              "The status of this buffer Control Entry."
          ::= { bufferControlEntry 13 }

      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."
          INDEX { captureBufferControlIndex, captureBufferIndex }
          ::= { captureBufferTable 1 }

      CaptureBufferEntry ::= SEQUENCE {
          captureBufferControlIndex   INTEGER (1..65535),
          captureBufferIndex          INTEGER,
          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
          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."
          ::= { 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
              filterPacketStatus.  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.

              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.  Three traps are defined in a companion
      -- document: risingAlarm, fallingAlarm, and packetMatch.
      -- 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."
          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         INTEGER
      }

      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."
          INDEX { logEventIndex, logIndex }

          ::= { logTable 1 }

      LogEntry ::= SEQUENCE {
          logEventIndex           INTEGER (1..65535),
          logIndex                INTEGER,
          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
          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 }

      END

Acknowledgments

This document was produced by the IETF Remote Network Monitoring Working Group.

In addition, the comments of the following individuals are also acknowledged:

  Anne Ambler             Spider Systems
  Steve Bostock           Novell
  Gigi Chu                Hewlett-Packard
  Chuck Davin             MIT
  Gary Ellis              Hewlett-Packard
  Mike Erlinger           Lexcel
  Stephen Grau            Novell
  Martin Gray             Spider Systems
  Mark Hoerth             Hewlett-Packard
  Tim Lee-Thorp           Network General
  Anil Singhal            Frontier Software
  David Stevens           Network General
  Gerard White            Concord Communications

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", RFC 1155,
   Performance Systems International, Hughes LAN Systems, May 1990.

[4] McCloghrie K., and M. Rose, "Management Information Base for

   Network Management of TCP/IP-based internets", RFC 1156, Hughes
   LAN Systems, Performance Systems International, May 1990.

[5] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple

   Network Management Protocol", RFC 1157, SNMP Research,
   Performance Systems International, Performance Systems
   International, MIT Laboratory for Computer Science, May 1990.

[6] McCloghrie K., and M. Rose, Editors, "Management Information Base

   for Network Management of TCP/IP-based internets", RFC 1213,
   Performance Systems International, March 1991.

[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.

Security Considerations

Security issues are not discussed in this memo.

Author's Address

Steven Waldbusser Carnegie Mellon University 4910 Forbes Ave. Pittsburgh, PA 15213

Phone: (412) 268-6628

EMail: [email protected]