[Text version]

Network Working Group Request for Comments: 4502 Obsoletes: 2021 Updates: 3273 Category: Standards Track

S. Waldbusser May 2006

Status of This Memo

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright © The Internet Society (2006).

Abstract

This document 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.

This document obsoletes RFC 2021, updates RFC 3273, and contains a new version of the RMON2-MIB module.

Table of Contents

   1. The Internet-Standard Management Framework ......................2
   2. Overview ........................................................2
      2.1. Remote Network Management Goals ............................3
      2.2. Structure of MIB ...........................................4
   3. Control of Remote Network Monitoring Devices ....................6
      3.1. Resource Sharing among Multiple Management Stations ........7
      3.2. Row Addition among Multiple Management Stations ............8
   4. Conventions .....................................................9
   5. RMON 2 Conventions .............................................10
      5.1. Usage of the Term Application Level .......................10
      5.2. Protocol Directory and Limited Extensibility ..............10
      5.3. Errors in Packets .........................................11
   6. Definitions ....................................................11
   7. Security Considerations .......................................130
   8. Appendix - TimeFilter Implementation Notes ....................132
   9. Changes since RFC 2021 ........................................138
   10. Acknowledgements .............................................140
   11. References ...................................................140
      11.1. Normative References ....................................140
      11.2. Informative References ..................................140

1. The Internet-Standard Management Framework

For a detailed overview of the documents that describe the current Internet-Standard Management Framework, please refer to section 7 of RFC 3410 [RFC3410].

Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. MIB objects are generally accessed through the Simple Network Management Protocol (SNMP). Objects in the MIB are defined using the mechanisms defined in the Structure of Management Information (SMI). This memo specifies a MIB module that is compliant to the SMIv2, which is described in STD 58, RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580 [RFC2580].

2. Overview

The RMON2 MIB defines objects that provide RMON analysis up to the application layer.

Remote network monitoring devices, often called monitors or probes, 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, which is often geographically remote.

The objects defined in this document are intended to serve as an interface between an RMON agent and an RMON management application and are not intended for direct manipulation by humans. While some users may tolerate the direct display of some of these objects, few will tolerate the complexity of manually manipulating objects to accomplish row creation. The management application should handle these functions.

2.1. Remote Network Management Goals

   o  Offline Operation

      There are times when a management station will not be in constant
      contact with its remote monitoring devices.  This sometimes occurs
      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 the 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  Proactive Monitoring

      Given the resources available on the monitor, it is potentially
      helpful for it to run diagnostics continuously 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 of the cause of
      the problem.

   o  Problem Detection and Reporting

      The monitor can be configured to recognize conditions, most
      notably error conditions, and to check for them continuously.
      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 order to provide
      disaster recovery.  Because environments with multiple management
      stations are common, the remote network monitoring device has to
      deal with more than one management station, potentially using its
      resources concurrently.

2.2. Structure of MIB

The objects are arranged into the following groups:

      - protocol directory

      - protocol distribution

      - address mapping

      - network layer host

      - network layer matrix

      - application layer host

      - application layer matrix

      - user history

      - probe configuration

These groups are the basic units 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 network layer matrix group must implement the nlMatrixSDTable and the nlMatrixDSTable.

Implementations of this MIB must also implement the IF-MIB [RFC2863].

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.

This document also contains AUGMENTing tables to extend some tables defined in the RMON MIB [RFC2819]. These extensions include the following:

      1) Adding the DroppedFrames and LastCreateTime conventions to each
         table defined in the RMON MIB.

      2) Augmenting the RMON filter table with a mechanism that allows
         filtering based on an offset from the beginning of a particular
         protocol, even if the protocol headers are of variable length.

      3) Augmenting the RMON filter and capture status bits with
         additional bits for WAN media and generic media.  These bits
         are defined here as follows:

         Bit     Definition

         6       For WAN media, this bit is set for packets
                 coming from one direction and cleared for
                 packets coming from the other direction.
                 It is an implementation-specific matter
                 as to which bit is assigned to which
                 direction, but it must be consistent for
                 all packets received by the agent.  If
                 the agent knows which end of the link is
                 "local" and which end is "network", the bit
                 should be set for packets from the "local"
                 side and should be cleared for packets from
                 the "network" side.

         7       For any media, this bit is set for any packet
                 with a physical layer error.  This bit may be
                 set in addition to other media-specific bits
                 that denote the same condition.

         8       For any media, this bit is set for any packet
                 that is too short for the media.  This bit may
                 be set in addition to other media-specific
                 bits that denote the same condition.

         9       For any media, this bit is set for any packet
                 that is too long for the media.  This bit may
                 be set in addition to other media-specific bits
                 that denote the same condition.

These enhancements are implemented by RMON-2 probes that also implement RMON and do not add any requirements to probes that are compliant to just RMON.

3. 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 that parameters 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 not active. Thus, the method for modifying these parameters is to deactivate the entry, perform the SNMP Set operations to modify the entry, and then reactivate the entry. Deleting the control entry causes the deletion of any associated data entries, which 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.

3.1. 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 the following:

      o  Two management stations wish to use resources simultaneously
         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 that others may use them.

The OwnerString 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 unilaterally to 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 share the resources more effectively.

There is often default functionality that the device or the administrator of the probe (often the network administrator) wishes to set up. The resources associated with this functionality are then owned by the device itself or by the network administrator, and they are intended to be long-lived. In this case, the device or the administrator 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.

Resources on a probe are scarce and are typically allocated when control rows are created by an application. Since many applications may be using a probe simultaneously, indiscriminate allocation of resources to particular applications is very likely to cause resource shortages in the probe.

When a network management station wishes to utilize a function in a monitor, it is encouraged first to 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.

Note that a management application should have the most trust in a monitor-owned row, because it should be changed very infrequently. A row owned by the management application is less long-lived because a network administrator is more likely to reassign resources from a row that is in use by one user than those from a monitor-owned row that is potentially in use by many users. A row owned by another application would be even less long-lived because the other application may delete or modify that row completely at its discretion.

3.2. Row Addition among Multiple Management Stations

The addition of new rows is achieved using the RowStatus Textual Convention [RFC2579]. 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 the 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 row status object to
         active.

If the latter option 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 option, 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 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.

In the RMON MIB [RFC2819], the EntryStatus textual convention was introduced to provide this mutual exclusion function. Since then, this function was added to the SNMP framework as the RowStatus textual convention. The RowStatus textual convention is used for the definition of all new tables.

When a manager wishes to create a new control entry, it needs to choose an index for that row. It may choose this index in a variety of ways, hopefully minimizing the chances that the index is in use by another manager. If the index is in use, the mechanism mentioned previously will guard against collisions. Examples of schemes to choose index values include random selection or scanning the control table while looking for the first unused index. Because index values may be any valid value in the range and are chosen by the manager, the agent must allow a row to be created with any unused index value if it has the resources to create a new row.

Some tables in this MIB reference other tables within this MIB. When creating or deleting entries in these tables, it is generally allowable for dangling references to exist. There is no defined order for creating or deleting entries in these tables.

4. Conventions

The following conventions are used throughout the RMON MIB and its companion documents.

   Good Packets

      Good packets are error-free packets that have a valid frame
      length.  For example, on Ethernet, good packets are error-free
      packets that are between 64 octets and 1518 octets long.  They
      follow the form defined in IEEE 802.3 section 3.2.all.

   Bad Packets

      Bad packets are packets that have proper framing and are therefore
      recognized as packets, but that contain errors within the packet
      or have an invalid length.  For example, on Ethernet, bad packets
      have a valid preamble and SFD but have a bad CRC, or they are
      either shorter than 64 octets or longer than 1518 octets.

5. RMON 2 Conventions

The following practices and conventions are introduced in the RMON 2 MIB.

5.1. Usage of the Term "Application Level"

There are many cases in this MIB where the term "Application Level" is used to describe a class of protocols or a capability. This does not typically mean a protocol that is an OSI Layer 7 protocol. Rather, it is used to identify a class of protocols that is not limited to MAC-layer and network-layer protocols, but can also include transport, session, presentation, and application-layer protocols.

5.2. Protocol Directory and Limited Extensibility

Every RMON 2 implementation will have the capability to parse certain types of packets and identify their protocol type at multiple levels. The protocol directory presents an inventory of protocol types the probe is capable of monitoring and allows the addition, deletion, and configuration of protocol types in this list.

One concept deserves special attention: the "limited extensibility" of the protocol directory table. Using the RMON 2 model, protocols are detected by static software that has been written at implementation time. Therefore, as a matter of configuration, an implementation cannot suddenly learn how to parse new packet types. However, an implementation may be written such that the software knows where the demultiplexing field is for a particular protocol, and it can be written in such a way that the decoding of the next layer up is table driven. This works when the code has been written to accommodate it and can be extended no more than one level higher. This extensibility is called "limited extensibility" to highlight these limitations. However, this can be a very useful tool.

For example, suppose that an implementation has C code that understands how to decode IP packets on any of several ethernet encapsulations, and also knows how to interpret the IP protocol field to recognize UDP packets and how to decode the UDP port number fields. That implementation may be table driven so that among the many different UDP port numbers possible, it is configured to recognize 161 as SNMP, port 53 as DNS, and port 69 as TFTP. The limited extensibility of the protocol directory table would allow an SNMP operation to create an entry that would create an additional table mapping for UDP that would recognize UDP port 123 as NTP and begin counting such packets.

This limited extensibility is an option that an implementation can choose to allow or disallow for any protocol that has child protocols.

5.3. Errors in Packets

Packets with link-level errors are not counted anywhere in this MIB because most variables in this MIB require the decoding of the contents of the packet, which is meaningless if there is a link-level error.

Packets in which protocol errors are detected are counted for all protocols below the layer in which the error was encountered. The implication of this is that packets in which errors are detected at the network-layer are not counted anywhere in this MIB, while packets with errors detected at the transport layer may have network-layer statistics counted.

6. Definitions

RMON2-MIB DEFINITIONS ::= BEGIN
IMPORTS
    MODULE-IDENTITY, OBJECT-TYPE, Counter32, Integer32,
    Gauge32, IpAddress, TimeTicks, mib-2         FROM SNMPv2-SMI
    TEXTUAL-CONVENTION, RowStatus, DisplayString, TimeStamp
                                                 FROM SNMPv2-TC
    MODULE-COMPLIANCE, OBJECT-GROUP              FROM SNMPv2-CONF
    ifIndex                                      FROM IF-MIB
    OwnerString, statistics, history, hosts,
    matrix, filter, etherStatsEntry, historyControlEntry,
    hostControlEntry, matrixControlEntry, filterEntry,
    channelEntry                    FROM RMON-MIB
    tokenRing, tokenRingMLStatsEntry, tokenRingPStatsEntry,

    ringStationControlEntry, sourceRoutingStatsEntry
                                    FROM TOKEN-RING-RMON-MIB;
--  Remote Network Monitoring MIB

rmon MODULE-IDENTITY
    LAST-UPDATED "200605020000Z"    -- May 2, 2006
    ORGANIZATION "IETF RMON MIB Working Group"
    CONTACT-INFO
        "Author:
                     Steve Waldbusser
             Phone:  +1-650-948-6500
             Fax :   +1-650-745-0671
             Email:  waldbusser@nextbeacon.com

         Working Group Chair:
                     Andy Bierman
             E-mail: ietf@andybierman.com

         Working Group Mailing List: <rmonmib@ietf.org>
         To subscribe send email to: <rmonmib-request@ietf.org>    "
    DESCRIPTION
        "The MIB module for managing remote monitoring
         device implementations.  This MIB module
         extends the architecture introduced in the original
         RMON MIB as specified in RFC 2819.

         Copyright © The Internet Society (2006).  This version of
         this MIB module is part of RFC 4502;  see the RFC itself for
         full legal notices."

    REVISION "200605020000Z"    -- May 2, 2006
    DESCRIPTION
        "This version updates the proposed-standard version of the
        RMON2 MIB (published as RFC 2021) by adding 2 new
        enumerations to the nlMatrixTopNControlRateBase object and
        4 new enumerations to the alMatrixTopNControlRateBase object.
        These new enumerations support the creation of high-capacity
        topN reports in the High Capacity RMON MIB [RFC3273].

        Additionally, the following objects have been deprecated, as
        they have not had enough independent implementations to
        demonstrate interoperability to meet the requirements of a
        Draft Standard:

        probeDownloadFile
        probeDownloadTFTPServer
        probeDownloadAction
        probeDownloadStatus

        serialMode
        serialProtocol
        serialTimeout
        serialModemInitString
        serialModemHangUpString
        serialModemConnectResp
        serialModemNoConnectResp
        serialDialoutTimeout
        serialStatus
        serialConnectDestIpAddress
        serialConnectType
        serialConnectDialString
        serialConnectSwitchConnectSeq
        serialConnectSwitchDisconnectSeq
        serialConnectSwitchResetSeq
        serialConnectOwner
        serialConnectStatus
        netConfigIPAddress
        netConfigSubnetMask
        netConfigStatus
        netDefaultGateway
        tokenRingMLStats2DroppedFrames
        tokenRingMLStats2CreateTime
        tokenRingPStats2DroppedFrames
        tokenRingPStats2CreateTime
        ringStationControl2DroppedFrames
        ringStationControl2CreateTime
        sourceRoutingStats2DroppedFrames
        sourceRoutingStats2CreateTime
        trapDestIndex
        trapDestCommunity
        trapDestProtocol
        trapDestAddress
        trapDestOwner
        trapDestStatus

        In addition, two corrections were made.  The LastCreateTime
        Textual Convention had been defined with a base type of
        another textual convention, which isn't allowed in SMIv2.  The
        definition has been modified to use TimeTicks as the base
        type.

        Further, the SerialConfigEntry SEQUENCE definition included
        sub-typing information that is not allowed in SMIv2.  This
        information has been deleted.  Ranges were added to a number of
        objects and textual-conventions to constrain their maximum
        (and sometimes minimum) sizes.  The addition of these ranges
        documents existing practice for these objects.  These objects

        are:
            ControlString
            protocolDirID
            protocolDirParameters
            addressMapNetworkAddress
            nlHostAddress
            nlMatrixSDSourceAddress
            nlMatrixSDDestAddress
            nlMatrixDSSourceAddress
            nlMatrixDSDestAddress
            nlMatrixTopNSourceAddress
            nlMatrixTopNDestAddress
            alHostEntry
            alMatrixSDEntry
            alMatrixDSEntry
            alMatrixTopNSourceAddress
            alMatrixTopNDestAddress

        Finally, the TimeFilter TC has been updated to encourage agent
        implementations that allow a MIB walk to behave well even when
        performed by an application that is not aware of the special
        TimeFilter semantics."

    REVISION "200207080000Z"        -- 08 July, 2002
    DESCRIPTION
        "Added new enumerations to support the High-Capacity RMON
        MIB as defined in RFC 3273.  Also fixed some typos and
        added clarifications."

    REVISION "199605270000Z"    -- 27 May, 1996
    DESCRIPTION
        "Original version.  Published as RFC 2021."
    ::= { mib-2 16 }

-- { rmon 1 } through { rmon 10 } are defined in RMON and -- the Token Ring RMON MIB [RFC1513]

    protocolDir     OBJECT IDENTIFIER ::= { rmon 11 }
    protocolDist    OBJECT IDENTIFIER ::= { rmon 12 }
    addressMap      OBJECT IDENTIFIER ::= { rmon 13 }
    nlHost          OBJECT IDENTIFIER ::= { rmon 14 }
    nlMatrix        OBJECT IDENTIFIER ::= { rmon 15 }
    alHost          OBJECT IDENTIFIER ::= { rmon 16 }
    alMatrix        OBJECT IDENTIFIER ::= { rmon 17 }
    usrHistory      OBJECT IDENTIFIER ::= { rmon 18 }
    probeConfig     OBJECT IDENTIFIER ::= { rmon 19 }
    rmonConformance OBJECT IDENTIFIER ::= { rmon 20 }

-- Textual Conventions

ZeroBasedCounter32 ::= TEXTUAL-CONVENTION
    STATUS current
    DESCRIPTION
        "This TC describes an object that counts events with the
        following semantics: objects of this type will be set to
        zero(0) on creation and will thereafter count appropriate
        events, wrapping back to zero(0) when the value 2^32 is
        reached.

        Provided that an application discovers the new object within
        the minimum time to wrap, it can use the initial value as a
        delta since it last polled the table of which this object is
        part.  It is important for a management station to be aware of
        this minimum time and the actual time between polls, and to
        discard data if the actual time is too long or there is no
        defined minimum time.

        Typically, this TC is used in tables where the INDEX space is
        constantly changing and/or the TimeFilter mechanism is in use."
    SYNTAX Gauge32

LastCreateTime ::= TEXTUAL-CONVENTION
    STATUS current
    DESCRIPTION
        "This TC describes an object that stores the value of the
        sysUpTime object at the last time its entry was created.

        This can be used for polling applications to determine that an
        entry has been deleted and re-created between polls, causing
        an otherwise undetectable discontinuity in the data.

        If sysUpTime is reset to zero as a result of a re-
        initialization of the network management (sub)system, then
        the values of all LastCreateTime objects are also reset.
        However, after approximately 497 days without a re-
        initialization, the sysUpTime object will reach 2^^32-1 and
        then increment to zero; in this case, existing values
        of TimeStamp objects do not change.  This can lead to
        ambiguities in the value of TimeStamp objects."
    SYNTAX TimeTicks

TimeFilter ::= TEXTUAL-CONVENTION
  STATUS        current
  DESCRIPTION
      "To be used for the index to a table.  Allows an application
      to download only those rows changed since a particular time.

      Note that this is not a history mechanism.  Only current values
      of underlying objects are returned; saved instance values
      associated with particular values of sysUpTime are not.

      An entry is considered changed if the value of any object in the
      entry changes, if the row is created, or if any object in the
      entry is created or deleted.  Note that deleted entries cannot
      be detected or downloaded.

      A time-filtered conceptual table is created by inserting a
      single object of SYNTAX TimeFilter as the first INDEX component
      in a copy of an existing basic conceptual table (i.e., any
      SEQUENCE without a TimeFilter INDEX component).  Thus, for
      each conceptual entry 'I' in the basic table, there exists N
      conceptual entries in the time-filtered version, indexed N.I,
      where 'N' is equal to the value of sysUpTime.

      When an application retrieves conceptual instances from a
      time-filtered table, and an INDEX value is provided for the
      TimeFilter INDEX component 'N', the agent will only consider
      returning basic conceptual entries (e.g., 'fooColumn.N.I') if
      any column within the basic conceptual entry has changed since
      sysUpTime 'N'.  If not, the basic conceptual entry will
      be ignored for the particular retrieval operation.

      When sysUpTime is equal to zero, this table shall be empty.

      One conceptual entry exists for each past value of sysUpTime,
      except that the whole table is purged should sysUpTime wrap.

      As an entry in a time-filtered table is updated (i.e., one of
      the columns in the basic conceptual table is changed), new
      conceptual entries are also created in the time-filtered version
      (which still shares the now updated object values with all other
      instances).  The number of unique time-filtered instances that
      are created is determined by the value of sysUpTime at which the
      basic entry was last updated.  One unique instance will exist
      for each value of sysUpTime at the last update time for the row.
      However, a new TimeFilter index instance is created for each new
      sysUpTime value.  The TimeFilter index values not associated
      with entry updates are called duplicate time-filtered instances.

      After some deployment experience, it has been determined that
      a time-filtered table is more efficient if the agent
      stops a MIB walk operation by skipping over rows with a
      TimeFilter index value higher than the value in the received
      GetNext/GetBulk request.  That is, instead of incrementing a
      TimeFilter index value, the agent will continue to the next

      object or table.  As a consequence, GetNext or GetBulk
      operations will provide only one pass through a time-filtered
      table.

      It is suggested that an agent implement a time-filtered table
      in this manner to improve performance and avoid a MIB walk
      getting stuck in time-filtered tables.  It is, however, still
      acceptable for an agent to implement a time-filtered table in
      the traditional manner (i.e., every conceptual time-filtered
      instance is returned in GetNext and GetBulk PDU responses), and
      management applications must be able to deal with such
      traditional implementations.

      See the appendix for further discussion of this textual
      convention.

      The following example is provided to demonstrate TimeFilter
      behavior:

      Consider the following basic conceptual table, basicFooTable.
      (Note that the basic version of a time-filtered table may not
      actually be defined.)

          basicFooTable:

          basicFooTable ...
          INDEX { fooIndex }

          BasicFooEntry {
             fooIndex     Integer32,
             fooCounts    Counter32
          }

      For this example, the basicFooTable contains two static
      conceptual entries (fooIndex equals '1' and '2'), created at
      time zero.  It also contains one dynamic conceptual entry
      (fooIndex equals '3'), which is created at time '3' and deleted
      at time '7'.

      The time-filtered version of the basicFooTable could be defined
      as follows:

          FooTable:

          fooTable ...
          INDEX { fooTimeMark, fooIndex }

          FooEntry {

             fooTimeMark  TimeFilter,
             fooIndex     Integer32,
             fooCounts    Counter32
          }

      Note that entries exist in the time-filtered conceptual table
      only if they actually exist in the underlying (basic) table.

      For this example, the fooTable will have three underlying
      basic entries (fooIndex == 1, 2, and 3), with the following
      activity (for sysUpTime equal 0 to 9):

         - fooEntry.N.1 is created at time '0' and most recently
           updated at time '6' to the value '5'.
         - fooEntry.N.2 is created at time '0' and most recently
           updated at time '8' to the value '9'.
         - fooEntry.N.3 is created at time '3', updated at time '5'
           to the value '17', and deleted at time '7'.

     The following tables show the values that would be returned for
     MIB walk operations with various TimeFilter values, done at
     different times.  An application issues a retrieval request at
     time 'T', with a TimeFilter value, 'N' (typically set to a lower
     value, such as the value of sysUpTime at the last polling cycle).

     The following values would be returned in a MIB walk of
     fooCounts.N if T equals '0' and N equals '0':

           fooCounts.N.I    Value
           ==========================
           fooCounts.0.1    0
           fooCounts.0.2    0

       Note that nothing is returned for fooCounts.0.3, since that
       entry does not exist at sysUpTime equals '0'.

     The following values would be returned in a full (traditional) MIB
     walk of fooCounts.N if T equals '3' and N equals '0':

           fooCounts.N.I    Value
           =======================
           fooCounts.0.1    0
           fooCounts.0.2    0
           fooCounts.0.3    0
           fooCounts.1.3    0
           fooCounts.2.3    0
           fooCounts.3.3    0

       Note that there are no instances for T equals 1 or 2 for the
       first two values of N, as these entries did not change
       since they were created at time '0'.

       Note that the current value for 'fooCounts.N.3' is returned
       here, even for values of N less than '3' (when the entry was
       created).  The agent only considers the current existence of an
       entry in the TimeFilter algorithm, not the time when the entry
       was created.

       Note that the instances 'fooCounts.0.3', 'fooCounts.1.3',
       and 'fooCounts.2.3' are duplicates and can be suppressed by the
       agent in a MIB walk.

     The following values would be returned in a full (traditional)
     MIB walk of fooCounts.N if T equals '6' and N equals '3':

           fooCounts.N.I    Value
           =======================
           fooCounts.3.1    5
           fooCounts.3.3    17
           fooCounts.4.1    5
           fooCounts.4.3    17
           fooCounts.5.1    5
           fooCounts.5.3    17
           fooCounts.6.1    5

        Note that no instances for entry 'fooCounts.N.2' are returned,
        since it has not changed since time '3'.

        Note that all instances except 'fooCounts.5.3' and
        'fooCounts.6.1' are duplicates and can be suppressed by the
        agent in a MIB walk.

     The following values would be returned in a full (traditional)
     MIB walk of fooCounts.N if T equals '9' and N equals '6':

           fooCounts.N.I    Value
           =======================
           fooCounts.6.1    5
           fooCounts.6.2    9
           fooCounts.7.2    9
           fooCounts.8.2    9

        Note that no instances for entry 'fooCounts.N.3' are returned,
        since it was deleted at time '7'.

        Note that instances 'fooCounts.6.2' and 'fooCounts.7.2'

        are duplicates and can be suppressed by the agent in a MIB
        walk."

  SYNTAX    TimeTicks

DataSource ::= TEXTUAL-CONVENTION
    STATUS        current
    DESCRIPTION
        "Identifies the source of the data that the associated
        function is configured to analyze.  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 [RFC2863], for the desired interface.

        For example, if an entry were to receive data from
        interface #1, this object would be set to ifIndex.1."
    SYNTAX      OBJECT IDENTIFIER

--
-- Protocol Directory Group
--
-- Lists the inventory of protocols the probe has the capability of
-- monitoring and allows the addition, deletion, and configuration of
-- entries in this list.

protocolDirLastChange OBJECT-TYPE
    SYNTAX      TimeStamp
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The value of sysUpTime at the time the protocol directory
        was last modified, either through insertions or deletions,
        or through modifications of the
        protocolDirAddressMapConfig, protocolDirHostConfig, or
        protocolDirMatrixConfig."
    ::= { protocolDir 1 }

protocolDirTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF ProtocolDirEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "This table lists the protocols that this agent has the
        capability to decode and count.  There is one entry in this
        table for each such protocol.  These protocols represent
        different network-layer, transport-layer, and higher-layer

        protocols.  The agent should boot up with this table
        preconfigured with those protocols that it knows about and
        wishes to monitor.  Implementations are strongly encouraged to
        support protocols higher than the network layer (at least for
        the protocol distribution group), even for implementations
        that don't support the application-layer groups."
    ::= { protocolDir 2 }

protocolDirEntry OBJECT-TYPE
    SYNTAX      ProtocolDirEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A conceptual row in the protocolDirTable.

         An example of the indexing of this entry is
         protocolDirLocalIndex.8.0.0.0.1.0.0.8.0.2.0.0, which is the
         encoding of a length of 8, followed by 8 subids encoding the
         protocolDirID of 1.2048, followed by a length of 2 and the
         2 subids encoding zero-valued parameters.

         Note that some combinations of index values may result in an
         index that exceeds 128 sub-identifiers in length, which exceeds
         the maximum for the SNMP protocol.  Implementations should take
         care to avoid such combinations."
    INDEX { protocolDirID, protocolDirParameters }
    ::= { protocolDirTable  1 }

ProtocolDirEntry ::= SEQUENCE {
    protocolDirID                   OCTET STRING,
    protocolDirParameters           OCTET STRING,
    protocolDirLocalIndex           Integer32,
    protocolDirDescr                DisplayString,
    protocolDirType                 BITS,
    protocolDirAddressMapConfig     INTEGER,
    protocolDirHostConfig           INTEGER,
    protocolDirMatrixConfig         INTEGER,
    protocolDirOwner                OwnerString,
    protocolDirStatus               RowStatus
}

protocolDirID OBJECT-TYPE
    SYNTAX      OCTET STRING  (SIZE (4..128))
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A unique identifier for a particular protocol.  Standard
        identifiers will be defined in such a manner that they

        can often be used as specifications for new protocols - i.e.,
        a tree-structured assignment mechanism that matches the
        protocol encapsulation 'tree' and that has algorithmic
        assignment mechanisms for certain subtrees.  See RFC 2074 for
        more details.

        Despite the algorithmic mechanism, the probe will only place
        entries in here for those protocols it chooses to collect.  In
        other words, it need not populate this table with all
        possible ethernet protocol types, nor need it create them on
        the fly when it sees them.  Whether it does these
        things is a matter of product definition (cost/benefit,
        usability) and is up to the designer of the product.

        If an entry is written to this table with a protocolDirID that
        the agent doesn't understand, either directly or
        algorithmically, the SET request will be rejected with an
        inconsistentName or badValue (for SNMPv1) error."
    ::= { protocolDirEntry 1 }

protocolDirParameters OBJECT-TYPE
    SYNTAX      OCTET STRING (SIZE (1..32))
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A set of parameters for the associated protocolDirID.
        See the associated RMON2 Protocol Identifiers document
        for a description of the possible parameters.  There
        will be one octet in this string for each sub-identifier in
        the protocolDirID, and the parameters will appear here in the
        same order as the associated sub-identifiers appear in the
        protocolDirID.

        Every node in the protocolDirID tree has a different, optional
        set of parameters defined (that is, the definition of
        parameters for a node is optional).  The proper parameter
        value for each node is included in this string.  Note that the
        inclusion of a parameter value in this string for each node is
        not optional.  What is optional is that a node may have no
        parameters defined, in which case the parameter field for that
        node will be zero."
    ::= { protocolDirEntry 2 }

protocolDirLocalIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..2147483647)
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION

        "The locally arbitrary but unique identifier associated
        with this protocolDir entry.

        The value for each supported protocol must remain constant at
        least from one re-initialization of the entity's network
        management system to the next re-initialization, except that
        if a protocol is deleted and re-created, it must be re-created
        with a new value that has not been used since the last
        re-initialization.

        The specific value is meaningful only within a given SNMP
        entity.  A protocolDirLocalIndex must not be re-used until the
        next agent restart in the event that the protocol directory
        entry is deleted."
    ::= { protocolDirEntry 3 }

protocolDirDescr OBJECT-TYPE
    SYNTAX      DisplayString (SIZE (1..64))
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "A textual description of the protocol encapsulation.
        A probe may choose to describe only a subset of the
        entire encapsulation (e.g., only the highest layer).

        This object is intended for human consumption only.

        This object may not be modified if the associated
        protocolDirStatus object is equal to active(1)."
    ::= { protocolDirEntry 4 }

protocolDirType OBJECT-TYPE
    SYNTAX      BITS {
                    extensible(0),
                    addressRecognitionCapable(1)
                }
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object describes 2 attributes of this protocol
         directory entry.

         The presence or absence of the 'extensible' bit describes
         whether this protocol directory entry can be extended
         by the user by creating protocol directory entries that are
         children of this protocol.

         An example of an entry that will often allow extensibility is

         'ip.udp'.  The probe may automatically populate some children
         of this node, such as 'ip.udp.snmp' and 'ip.udp.dns'.
         A probe administrator or user may also populate additional
         children via remote SNMP requests that create entries in this
         table.  When a child node is added for a protocol for which the
         probe has no built-in support extending a parent node (for
         which the probe does have built-in support),
         that child node is not extendable.  This is termed 'limited
         extensibility'.

         When a child node is added through this extensibility
         mechanism, the values of protocolDirLocalIndex and
         protocolDirType shall be assigned by the agent.

         The other objects in the entry will be assigned by the
         manager who is creating the new entry.

         This object also describes whether this agent can
         recognize addresses for this protocol, should it be a
         network-level protocol.  That is, while a probe may be able
         to recognize packets of a particular network-layer protocol
         and count them, it takes additional logic to be able to
         recognize the addresses in this protocol and to populate
         network-layer or application-layer tables with the addresses
         in this protocol.  If this bit is set, the agent will
         recognize network-layer addresses for this protocol and
         populate the network- and application-layer host and matrix
         tables with these protocols.

         Note that when an entry is created, the agent will supply
         values for the bits that match the capabilities of the agent
         with respect to this protocol.  Note that since row creations
         usually exercise the limited extensibility feature, these
         bits will usually be set to zero."
    ::= { protocolDirEntry 5 }

protocolDirAddressMapConfig OBJECT-TYPE
    SYNTAX      INTEGER {
                    notSupported(1),
                    supportedOff(2),
                    supportedOn(3)
                }
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "This object describes and configures the probe's support for
        address mapping for this protocol.  When the probe creates
        entries in this table for all protocols that it understands,

        it will set the entry to notSupported(1) if it doesn't have
        the capability to perform address mapping for the protocol or
        if this protocol is not a network-layer protocol.  When
        an entry is created in this table by a management operation as
        part of the limited extensibility feature, the probe must set
        this value to notSupported(1), because limited extensibility
        of the protocolDirTable does not extend to interpreting
        addresses of the extended protocols.

        If the value of this object is notSupported(1), the probe
        will not perform address mapping for this protocol and
        shall not allow this object to be changed to any other value.
        If the value of this object is supportedOn(3), the probe
        supports address mapping for this protocol and is configured
        to perform address mapping for this protocol for all
        addressMappingControlEntries and all interfaces.
        If the value of this object is supportedOff(2), the probe
        supports address mapping for this protocol but is configured
        to not perform address mapping for this protocol for any
        addressMappingControlEntries and all interfaces.
        Whenever this value changes from supportedOn(3) to
        supportedOff(2), the probe shall delete all related entries in
        the addressMappingTable."
    ::= { protocolDirEntry 6 }

protocolDirHostConfig OBJECT-TYPE
    SYNTAX      INTEGER {
                    notSupported(1),
                    supportedOff(2),
                    supportedOn(3)
                }
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "This object describes and configures the probe's support for
        the network-layer and application-layer host tables for this
        protocol.  When the probe creates entries in this table for
        all protocols that it understands, it will set the entry to
        notSupported(1) if it doesn't have the capability to track the
        nlHostTable for this protocol or if the alHostTable is
        implemented but doesn't have the capability to track this
        protocol.  Note that if the alHostTable is implemented, the
        probe may only support a protocol if it is supported in both
        the nlHostTable and the alHostTable.

        If the associated protocolDirType object has the
        addressRecognitionCapable bit set, then this is a network-
        layer protocol for which the probe recognizes addresses, and

        thus the probe will populate the nlHostTable and alHostTable
        with addresses it discovers for this protocol.

        If the value of this object is notSupported(1), the probe
        will not track the nlHostTable or alHostTable for this
        protocol and shall not allow this object to be changed to any
        other value.  If the value of this object is supportedOn(3),
        the probe supports tracking of the nlHostTable and alHostTable
        for this protocol and is configured to track both tables
        for this protocol for all control entries and all interfaces.
        If the value of this object is supportedOff(2), the probe
        supports tracking of the nlHostTable and alHostTable for this
        protocol but is configured to not track these tables
        for any control entries or interfaces.
        Whenever this value changes from supportedOn(3) to
        supportedOff(2), the probe shall delete all related entries in
        the nlHostTable and alHostTable.

        Note that since each alHostEntry references 2 protocol
        directory entries, one for the network address and one for the
        type of the highest protocol recognized, an entry will
        only be created in that table if this value is supportedOn(3)
        for both protocols."
    ::= { protocolDirEntry 7 }

protocolDirMatrixConfig OBJECT-TYPE
    SYNTAX      INTEGER {
                    notSupported(1),
                    supportedOff(2),
                    supportedOn(3)
                }
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "This object describes and configures the probe's support for
        the network-layer and application-layer matrix tables for this
        protocol.  When the probe creates entries in this table for
        all protocols that it understands, it will set the entry to
        notSupported(1) if it doesn't have the capability to track the
        nlMatrixTables for this protocol or if the alMatrixTables are
        implemented but don't have the capability to track this
        protocol.  Note that if the alMatrix tables are implemented,
        the probe may only support a protocol if it is supported in
        both of the nlMatrixTables and both of the
        alMatrixTables.

        If the associated protocolDirType object has the
        addressRecognitionCapable bit set, then this is a network-

        layer protocol for which the probe recognizes addresses, and
        thus the probe will populate both of the nlMatrixTables and
        both of the alMatrixTables with addresses it discovers for
        this protocol.

        If the value of this object is notSupported(1), the probe
        will not track either of the nlMatrixTables or the
        alMatrixTables for this protocol and shall not allow this
        object to be changed to any other value.  If the value of this
        object is supportedOn(3), the probe supports tracking of both
        of the nlMatrixTables and (if implemented) both of the
        alMatrixTables for this protocol and is configured to track
        these tables for this protocol for all control entries and all
        interfaces.  If the value of this object is supportedOff(2),
        the probe supports tracking of both of the nlMatrixTables and
        (if implemented) both of the alMatrixTables for this protocol
        but is configured to not track these tables for this
        protocol for any control entries or interfaces.
        Whenever this value changes from supportedOn(3) to
        supportedOff(2), the probe shall delete all related entries in
        the nlMatrixTables and the alMatrixTables.

        Note that since each alMatrixEntry references 2 protocol
        directory entries, one for the network address and one for the
        type of the highest protocol recognized, an entry will
        only be created in that table if this value is supportedOn(3)
        for both protocols."
    ::= { protocolDirEntry 8 }

protocolDirOwner OBJECT-TYPE
    SYNTAX      OwnerString
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The entity that configured this entry and is
        therefore using the resources assigned to it."
    ::= { protocolDirEntry 9 }

protocolDirStatus OBJECT-TYPE
    SYNTAX      RowStatus
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The status of this protocol directory entry.

        An entry may not exist in the active state unless all
        objects in the entry have an appropriate value.

        If this object is not equal to active(1), all associated
        entries in the nlHostTable, nlMatrixSDTable, nlMatrixDSTable,
        alHostTable, alMatrixSDTable, and alMatrixDSTable shall be
        deleted."
    ::= { protocolDirEntry 10 }

--
-- Protocol Distribution Group  (protocolDist)
--
-- Collects the relative amounts of octets and packets for the
-- different protocols detected on a network segment.
--    protocolDistControlTable,
--    protocolDistStatsTable

protocolDistControlTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF ProtocolDistControlEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "Controls the setup of protocol type distribution statistics
        tables.

        Implementations are encouraged to add an entry per monitored
        interface upon initialization so that a default collection
        of protocol statistics is available.

        Rationale:
        This table controls collection of very basic statistics
        for any or all of the protocols detected on a given interface.
        An NMS can use this table to quickly determine bandwidth
        allocation utilized by different protocols.

        A media-specific statistics collection could also
        be configured (e.g., etherStats, trPStats) to easily obtain
        total frame, octet, and droppedEvents for the same
        interface."
    ::= { protocolDist 1 }

protocolDistControlEntry OBJECT-TYPE
    SYNTAX      ProtocolDistControlEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A conceptual row in the protocolDistControlTable.

         An example of the indexing of this entry is
         protocolDistControlDroppedFrames.7"
    INDEX { protocolDistControlIndex }

    ::= { protocolDistControlTable 1 }

ProtocolDistControlEntry ::= SEQUENCE {
    protocolDistControlIndex                Integer32,
    protocolDistControlDataSource           DataSource,
    protocolDistControlDroppedFrames        Counter32,
    protocolDistControlCreateTime           LastCreateTime,
    protocolDistControlOwner                OwnerString,
    protocolDistControlStatus               RowStatus
}

protocolDistControlIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..65535)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A unique index for this protocolDistControlEntry."
    ::= { protocolDistControlEntry 1 }

protocolDistControlDataSource OBJECT-TYPE
    SYNTAX      DataSource
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The source of data for the this protocol distribution.

        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
        protocolDistControlStatus object is equal to active(1)."
    ::= { protocolDistControlEntry 2 }

protocolDistControlDroppedFrames OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
       "The total number of frames that were received by the probe
        and therefore not accounted for in the *StatsDropEvents, but
        that the probe chose not to count for this entry for
        whatever reason.  Most often, this event occurs when the probe
        is out of some resources and decides to shed load from this
        collection.

        This count does not include packets that were not counted
        because they had MAC-layer errors.

        Note that, unlike the dropEvents counter, this number is the
        exact number of frames dropped."
    ::= { protocolDistControlEntry 3 }

protocolDistControlCreateTime OBJECT-TYPE
    SYNTAX     LastCreateTime
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The value of sysUpTime when this control entry was last
        activated.  This can be used by the management station to
        ensure that the table has not been deleted and recreated
        between polls."
    ::= { protocolDistControlEntry 4 }

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

protocolDistControlStatus OBJECT-TYPE
    SYNTAX      RowStatus
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The status of this row.

        An entry may not exist in the active state unless all
        objects in the entry have an appropriate value.

        If this object is not equal to active(1), all associated
        entries in the protocolDistStatsTable shall be deleted."
    ::= { protocolDistControlEntry 6 }

-- per interface protocol distribution statistics table
protocolDistStatsTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF ProtocolDistStatsEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "An entry is made in this table for every protocol in the
        protocolDirTable that has been seen in at least one packet.
        Counters are updated in this table for every protocol type
        that is encountered when parsing a packet, but no counters are

        updated for packets with MAC-layer errors.

        Note that if a protocolDirEntry is deleted, all associated
        entries in this table are removed."
    ::= { protocolDist 2 }

protocolDistStatsEntry OBJECT-TYPE
    SYNTAX      ProtocolDistStatsEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A conceptual row in the protocolDistStatsTable.

        The index is composed of the protocolDistControlIndex of the
        associated protocolDistControlEntry, followed by the
        protocolDirLocalIndex of the associated protocol that this
        entry represents.  In other words, the index identifies the
        protocol distribution an entry is a part of and the
        particular protocol that it represents.

        An example of the indexing of this entry is
        protocolDistStatsPkts.1.18"
    INDEX { protocolDistControlIndex, protocolDirLocalIndex }
    ::= { protocolDistStatsTable 1 }

ProtocolDistStatsEntry ::= SEQUENCE {
    protocolDistStatsPkts                    ZeroBasedCounter32,
    protocolDistStatsOctets                  ZeroBasedCounter32
}

protocolDistStatsPkts OBJECT-TYPE
    SYNTAX      ZeroBasedCounter32
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The number of packets of this protocol type received
        without errors.  Note that this is the number of
        link-layer packets, so if a single network-layer packet
        is fragmented into several link-layer frames, this counter
        is incremented several times."
    ::= { protocolDistStatsEntry 1 }

protocolDistStatsOctets OBJECT-TYPE
    SYNTAX      ZeroBasedCounter32
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The number of octets in packets of this protocol type

        received since it was added to the protocolDistStatsTable
        (excluding framing bits, but including FCS octets), except for
        those octets in packets that contained errors.

        Note that this doesn't count just those octets in the
        particular protocol frames but includes the entire packet
        that contained the protocol."
    ::= { protocolDistStatsEntry 2 }

--
-- Address Map Group   (addressMap)
--
-- Lists MAC address to network address bindings discovered by the
-- probe and what interface they were last seen on.
--    addressMapControlTable
--    addressMapTable

addressMapInserts OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The number of times an address mapping entry has been
        inserted into the addressMapTable.  If an entry is inserted,
        then deleted, and then inserted, this counter will be
        incremented by 2.

        Note that the table size can be determined by subtracting
        addressMapDeletes from addressMapInserts."
    ::= { addressMap 1 }

addressMapDeletes OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The number of times an address mapping entry has been
        deleted from the addressMapTable (for any reason).  If
        an entry is deleted, then inserted, and then deleted, this
        counter will be incremented by 2.

        Note that the table size can be determined by subtracting
        addressMapDeletes from addressMapInserts."
    ::= { addressMap 2 }

addressMapMaxDesiredEntries OBJECT-TYPE
    SYNTAX      Integer32 (-1..2147483647)
    MAX-ACCESS  read-write

    STATUS      current
    DESCRIPTION
        "The maximum number of entries that are desired in the
        addressMapTable.  The probe will not create more than
        this number of entries in the table but may choose to create
        fewer entries in this table for any reason, including the lack
        of resources.

        If this object is set to a value less than the current number
        of entries, enough entries are chosen in an
        implementation-dependent manner and deleted so that the number
        of entries in the table equals the value of this object.

        If this value is set to -1, the probe may create any number
        of entries in this table.

        This object may be used to control how resources are allocated
        on the probe for the various RMON functions."
    ::= { addressMap 3 }

addressMapControlTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF AddressMapControlEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A table to control the collection of mappings from network
         layer address to physical address to interface.

        Note that this is not like the typical RMON
        controlTable and dataTable in which each entry creates
        its own data table.  Each entry in this table enables the
        discovery of addresses on a new interface and the placement
        of address mappings into the central addressMapTable.

        Implementations are encouraged to add an entry per monitored
        interface upon initialization so that a default collection
        of address mappings is available."
    ::= { addressMap 4 }

addressMapControlEntry OBJECT-TYPE
    SYNTAX      AddressMapControlEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A conceptual row in the addressMapControlTable.

        An example of the indexing of this entry is
        addressMapControlDroppedFrames.1"

    INDEX { addressMapControlIndex }
    ::= { addressMapControlTable 1 }

AddressMapControlEntry ::= SEQUENCE {
    addressMapControlIndex              Integer32,
    addressMapControlDataSource         DataSource,
    addressMapControlDroppedFrames      Counter32,
    addressMapControlOwner              OwnerString,
    addressMapControlStatus             RowStatus
}

addressMapControlIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..65535)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A unique index for this entry in the addressMapControlTable."
    ::= { addressMapControlEntry 1 }

addressMapControlDataSource OBJECT-TYPE
    SYNTAX      DataSource
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The source of data for this addressMapControlEntry."
    ::= { addressMapControlEntry 2 }

addressMapControlDroppedFrames OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
       "The total number of frames that were received by the probe
        and therefore not accounted for in the *StatsDropEvents, but
        that the probe chose not to count for this entry for
        whatever reason.  Most often, this event occurs when the probe
        is out of some resources and decides to shed load from this
        collection.

        This count does not include packets that were not counted
        because they had MAC-layer errors.

        Note that, unlike the dropEvents counter, this number is the
        exact number of frames dropped."
    ::= { addressMapControlEntry 3 }

addressMapControlOwner OBJECT-TYPE
    SYNTAX      OwnerString

    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The entity that configured this entry and is
        therefore using the resources assigned to it."
    ::= { addressMapControlEntry 4 }

addressMapControlStatus OBJECT-TYPE
    SYNTAX      RowStatus
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The status of this addressMap control entry.

        An entry may not exist in the active state unless all
        objects in the entry have an appropriate value.

        If this object is not equal to active(1), all associated
        entries in the addressMapTable shall be deleted."
    ::= { addressMapControlEntry 5 }

addressMapTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF AddressMapEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A table of mappings from network layer address to physical
        address to interface.

        The probe will add entries to this table based on the source
        MAC and network addresses seen in packets without MAC-level
        errors.  The probe will populate this table for all protocols
        in the protocol directory table whose value of
        protocolDirAddressMapConfig is equal to supportedOn(3), and
        will delete any entries whose protocolDirEntry is deleted or
        has a protocolDirAddressMapConfig value of supportedOff(2)."
    ::= { addressMap 5 }

addressMapEntry OBJECT-TYPE
    SYNTAX      AddressMapEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A conceptual row in the addressMapTable.

        The protocolDirLocalIndex in the index identifies the network
        layer protocol of the addressMapNetworkAddress.

        An example of the indexing of this entry is
        addressMapSource.783495.18.4.128.2.6.6.11.1.3.6.1.2.1.2.2.1.1.1.

        Note that some combinations of index values may result in an
        index that exceeds 128 sub-identifiers in length, which exceeds
        the maximum for the SNMP protocol.  Implementations should take
        care to avoid such combinations."
    INDEX { addressMapTimeMark, protocolDirLocalIndex,
            addressMapNetworkAddress, addressMapSource }
    ::= { addressMapTable 1 }

AddressMapEntry ::= SEQUENCE {
    addressMapTimeMark                 TimeFilter,
    addressMapNetworkAddress           OCTET STRING,
    addressMapSource                   OBJECT IDENTIFIER,
    addressMapPhysicalAddress          OCTET STRING,
    addressMapLastChange               TimeStamp
}

addressMapTimeMark OBJECT-TYPE
    SYNTAX      TimeFilter
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A TimeFilter for this entry.  See the TimeFilter textual
        convention to see how this works."
    ::= { addressMapEntry 1 }

addressMapNetworkAddress OBJECT-TYPE
    SYNTAX      OCTET STRING (SIZE (1..255))
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "The network address for this relation.

        This is represented as an octet string with
        specific semantics and length as identified
        by the protocolDirLocalIndex component of the
        index.

        For example, if the protocolDirLocalIndex indicates an
        encapsulation of ip, this object is encoded as a length
        octet of 4, followed by the 4 octets of the IP address,
        in network byte order."
    ::= { addressMapEntry 2 }

addressMapSource OBJECT-TYPE
    SYNTAX      OBJECT IDENTIFIER

    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "The interface or port on which the associated network
         address was most recently seen.

        If this address mapping was discovered on an interface, this
        object shall identify the instance of the ifIndex
        object, defined in [RFC2863], for the desired interface.
        For example, if an entry were to receive data from
        interface #1, this object would be set to ifIndex.1.

        If this address mapping was discovered on a port, this
        object shall identify the instance of the rptrGroupPortIndex
        object, defined in [RFC2108], for the desired port.
        For example, if an entry were to receive data from
        group #1, port #1, this object would be set to
        rptrGroupPortIndex.1.1.

        Note that while the dataSource associated with this entry
        may only point to index objects, this object may at times
        point to repeater port objects.  This situation occurs when
        the dataSource points to an interface that is a locally
        attached repeater and the agent has additional information
        about the source port of traffic seen on that repeater."
    ::= { addressMapEntry 3 }

addressMapPhysicalAddress OBJECT-TYPE
    SYNTAX      OCTET STRING
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The last source physical address on which the associated
        network address was seen.  If the protocol of the associated
        network address was encapsulated inside of a network-level or
        higher protocol, this will be the address of the next-lower
        protocol with the addressRecognitionCapable bit enabled and
        will be formatted as specified for that protocol."
    ::= { addressMapEntry 4 }

addressMapLastChange OBJECT-TYPE
    SYNTAX      TimeStamp
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The value of sysUpTime at the time this entry was last
        created or the values of the physical address changed.

        This can be used to help detect duplicate address problems, in
        which case this object will be updated frequently."
    ::= { addressMapEntry 5 }

-- -- Network Layer Host Group -- -- Counts the amount of traffic sent from and to each network address -- discovered by the probe. -- Note that while the hlHostControlTable also has objects that -- control an optional alHostTable, implementation of the alHostTable is -- not required to fully implement this group.

hlHostControlTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF HlHostControlEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A list of higher-layer (i.e., non-MAC) host table control
        entries.

        These entries will enable the collection of the network- and
        application-level host tables indexed by network addresses.
        Both the network- and application-level host tables are
        controlled by this table so that they will both be created
        and deleted at the same time, further increasing the ease with
        which they can be implemented as a single datastore.  (Note that
        if an implementation stores application-layer host records in
        memory, it can derive network-layer host records from them.)

        Entries in the nlHostTable will be created on behalf of each
        entry in this table.  Additionally, if this probe implements
        the alHostTable, entries in the alHostTable will be created on
        behalf of each entry in this table.

        Implementations are encouraged to add an entry per monitored
        interface upon initialization so that a default collection
        of host statistics is available."
    ::= { nlHost 1 }

hlHostControlEntry OBJECT-TYPE
    SYNTAX      HlHostControlEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A conceptual row in the hlHostControlTable.

        An example of the indexing of this entry is

        hlHostControlNlDroppedFrames.1"
    INDEX { hlHostControlIndex }
    ::= { hlHostControlTable 1 }

HlHostControlEntry ::= SEQUENCE {
    hlHostControlIndex               Integer32,
    hlHostControlDataSource          DataSource,
    hlHostControlNlDroppedFrames     Counter32,
    hlHostControlNlInserts           Counter32,
    hlHostControlNlDeletes           Counter32,
    hlHostControlNlMaxDesiredEntries Integer32,
    hlHostControlAlDroppedFrames     Counter32,
    hlHostControlAlInserts           Counter32,
    hlHostControlAlDeletes           Counter32,
    hlHostControlAlMaxDesiredEntries Integer32,
    hlHostControlOwner               OwnerString,
    hlHostControlStatus              RowStatus
}

hlHostControlIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..65535)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "An index that uniquely identifies an entry in the
        hlHostControlTable.  Each such entry defines
        a function that discovers hosts on a particular
        interface and places statistics about them in the
        nlHostTable, and optionally in the alHostTable, on
        behalf of this hlHostControlEntry."
    ::= { hlHostControlEntry 1 }

hlHostControlDataSource OBJECT-TYPE
    SYNTAX      DataSource
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The source of data for the associated host tables.

        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
        hlHostControlStatus object is equal to active(1)."
    ::= { hlHostControlEntry 2 }

hlHostControlNlDroppedFrames OBJECT-TYPE

    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
       "The total number of frames that were received by the probe
        and therefore not accounted for in the *StatsDropEvents, but
        that the probe chose not to count for the associated
        nlHost entries for whatever reason.  Most often, this event
        occurs when the probe is out of some resources and decides to
        shed load from this collection.

        This count does not include packets that were not counted
        because they had MAC-layer errors.

        Note that if the nlHostTable is inactive because no protocols
        are enabled in the protocol directory, this value should be 0.

        Note that, unlike the dropEvents counter, this number is the
        exact number of frames dropped."
    ::= { hlHostControlEntry 3 }

hlHostControlNlInserts OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The number of times an nlHost entry has been
        inserted into the nlHost table.  If an entry is inserted, then
        deleted, and then inserted, this counter will be incremented
        by 2.

        To allow for efficient implementation strategies, agents may
        delay updating this object for short periods of time.  For
        example, an implementation strategy may allow internal
        data structures to differ from those visible via SNMP for
        short periods of time.  This counter may reflect the internal
        data structures for those short periods of time.

        Note that the table size can be determined by subtracting
        hlHostControlNlDeletes from hlHostControlNlInserts."
    ::= { hlHostControlEntry 4 }

hlHostControlNlDeletes OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The number of times an nlHost entry has been

        deleted from the nlHost table (for any reason).  If an entry
        is deleted, then inserted, and then deleted, this counter will
        be incremented by 2.

        To allow for efficient implementation strategies, agents may
        delay updating this object for short periods of time.  For
        example, an implementation strategy may allow internal
        data structures to differ from those visible via SNMP for
        short periods of time.  This counter may reflect the internal
        data structures for those short periods of time.

        Note that the table size can be determined by subtracting
        hlHostControlNlDeletes from hlHostControlNlInserts."
    ::= { hlHostControlEntry 5 }

hlHostControlNlMaxDesiredEntries OBJECT-TYPE
    SYNTAX      Integer32 (-1..2147483647)
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The maximum number of entries that are desired in the
        nlHostTable on behalf of this control entry.  The probe will
        not create more than this number of associated entries in the
        table but may choose to create fewer entries in this table
        for any reason, including the lack of resources.

        If this object is set to a value less than the current number
        of entries, enough entries are chosen in an
        implementation-dependent manner and deleted so that the number
        of entries in the table equals the value of this object.

        If this value is set to -1, the probe may create any number
        of entries in this table.  If the associated
        hlHostControlStatus object is equal to 'active', this
        object may not be modified.

        This object may be used to control how resources are allocated
        on the probe for the various RMON functions."
    ::= { hlHostControlEntry 6 }

hlHostControlAlDroppedFrames OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
       "The total number of frames that were received by the probe
        and therefore not accounted for in the *StatsDropEvents, but
        that the probe chose not to count for the associated

        alHost entries for whatever reason.  Most often, this event
        occurs when the probe is out of some resources and decides to
        shed load from this collection.

        This count does not include packets that were not counted
        because they had MAC-layer errors.

        Note that if the alHostTable is not implemented or is inactive
        because no protocols are enabled in the protocol directory,
        this value should be 0.

        Note that, unlike the dropEvents counter, this number is the
        exact number of frames dropped."
    ::= { hlHostControlEntry 7 }

hlHostControlAlInserts OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The number of times an alHost entry has been
        inserted into the alHost table.  If an entry is inserted, then
        deleted, and then inserted, this counter will be incremented
        by 2.

        To allow for efficient implementation strategies, agents may
        delay updating this object for short periods of time.  For
        example, an implementation strategy may allow internal
        data structures to differ from those visible via SNMP for
        short periods of time.  This counter may reflect the internal
        data structures for those short periods of time.

        Note that the table size can be determined by subtracting
        hlHostControlAlDeletes from hlHostControlAlInserts."
    ::= { hlHostControlEntry 8 }

hlHostControlAlDeletes OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The number of times an alHost entry has been
        deleted from the alHost table (for any reason).  If an entry
        is deleted, then inserted, and then deleted, this counter will
        be incremented by 2.

        To allow for efficient implementation strategies, agents may
        delay updating this object for short periods of time.  For

        example, an implementation strategy may allow internal
        data structures to differ from those visible via SNMP for
        short periods of time.  This counter may reflect the internal
        data structures for those short periods of time.

        Note that the table size can be determined by subtracting
        hlHostControlAlDeletes from hlHostControlAlInserts."
    ::= { hlHostControlEntry 9 }

hlHostControlAlMaxDesiredEntries OBJECT-TYPE
    SYNTAX      Integer32 (-1..2147483647)
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The maximum number of entries that are desired in the alHost
        table on behalf of this control entry.  The probe will not
        create more than this number of associated entries in the
        table but may choose to create fewer entries in this table
        for any reason, including the lack of resources.

        If this object is set to a value less than the current number
        of entries, enough entries are chosen in an
        implementation-dependent manner and deleted so that the number
        of entries in the table equals the value of this object.

        If this value is set to -1, the probe may create any number
        of entries in this table.  If the associated
        hlHostControlStatus object is equal to 'active', this
        object may not be modified.

        This object may be used to control how resources are allocated
        on the probe for the various RMON functions."
    ::= { hlHostControlEntry 10 }

hlHostControlOwner OBJECT-TYPE
    SYNTAX      OwnerString
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The entity that configured this entry and is
        therefore using the resources assigned to it."
    ::= { hlHostControlEntry 11 }

hlHostControlStatus OBJECT-TYPE
    SYNTAX      RowStatus
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION

        "The status of this hlHostControlEntry.

        An entry may not exist in the active state unless all
        objects in the entry have an appropriate value.

        If this object is not equal to active(1), all associated
        entries in the nlHostTable and alHostTable shall be deleted."
    ::= { hlHostControlEntry 12 }

nlHostTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF NlHostEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A collection of statistics for a particular network layer
        address that has been discovered on an interface of this
        device.

        The probe will populate this table for all network layer
        protocols in the protocol directory table whose value of
        protocolDirHostConfig is equal to supportedOn(3), and
        will delete any entries whose protocolDirEntry is deleted or
        has a protocolDirHostConfig value of supportedOff(2).

        The probe will add to this table all addresses seen
        as the source or destination address in all packets with no
        MAC errors, and will increment octet and packet counts in the
        table for all packets with no MAC errors."
::= { nlHost 2 }

nlHostEntry OBJECT-TYPE
    SYNTAX      NlHostEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A conceptual row in the nlHostTable.

        The hlHostControlIndex value in the index identifies the
        hlHostControlEntry on whose behalf this entry was created.
        The protocolDirLocalIndex value in the index identifies the
        network layer protocol of the nlHostAddress.

        An example of the indexing of this entry is
        nlHostOutPkts.1.783495.18.4.128.2.6.6.

        Note that some combinations of index values may result in an
        index that exceeds 128 sub-identifiers in length, which exceeds
        the maximum for the SNMP protocol.  Implementations should take

        care to avoid such combinations."
    INDEX { hlHostControlIndex, nlHostTimeMark,
            protocolDirLocalIndex, nlHostAddress }
    ::= { nlHostTable 1 }

NlHostEntry ::= SEQUENCE {
    nlHostTimeMark              TimeFilter,
    nlHostAddress               OCTET STRING,
    nlHostInPkts                ZeroBasedCounter32,
    nlHostOutPkts               ZeroBasedCounter32,
    nlHostInOctets              ZeroBasedCounter32,
    nlHostOutOctets             ZeroBasedCounter32,
    nlHostOutMacNonUnicastPkts  ZeroBasedCounter32,
    nlHostCreateTime            LastCreateTime
}

nlHostTimeMark OBJECT-TYPE
    SYNTAX      TimeFilter
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A TimeFilter for this entry.  See the TimeFilter textual
        convention to see how this works."
    ::= { nlHostEntry 1 }

nlHostAddress OBJECT-TYPE
    SYNTAX      OCTET STRING  (SIZE (1..255))
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "The network address for this nlHostEntry.

        This is represented as an octet string with
        specific semantics and length as identified
        by the protocolDirLocalIndex component of the index.

        For example, if the protocolDirLocalIndex indicates an
        encapsulation of IP, this object is encoded as a length
        octet of 4, followed by the 4 octets of the IP address,
        in network byte order."
    ::= { nlHostEntry 2 }

nlHostInPkts OBJECT-TYPE
    SYNTAX      ZeroBasedCounter32
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The number of packets without errors transmitted to

        this address since it was added to the nlHostTable.  Note that
        this is the number of link-layer packets, so if a single
        network-layer packet is fragmented into several link-layer
        frames, this counter is incremented several times."
    ::= { nlHostEntry 3 }

nlHostOutPkts OBJECT-TYPE
    SYNTAX      ZeroBasedCounter32
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The number of packets without errors transmitted by
        this address since it was added to the nlHostTable.  Note that
        this is the number of link-layer packets, so if a single
        network-layer packet is fragmented into several link-layer
        frames, this counter is incremented several times."
    ::= { nlHostEntry 4 }

nlHostInOctets OBJECT-TYPE
    SYNTAX      ZeroBasedCounter32
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The number of octets transmitted to this address
        since it was added to the nlHostTable (excluding
        framing bits, but including FCS octets), excluding
        octets in packets that contained errors.

        Note that this doesn't count just those octets in the particular
        protocol frames but includes the entire packet that contained
        the protocol."
    ::= { nlHostEntry 5 }

nlHostOutOctets OBJECT-TYPE
    SYNTAX      ZeroBasedCounter32
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The number of octets transmitted by this address
        since it was added to the nlHostTable (excluding
        framing bits, but including FCS octets), excluding
        octets in packets that contained errors.

        Note that this doesn't count just those octets in the particular
        protocol frames but includes the entire packet that contained
        the protocol."
    ::= { nlHostEntry 6 }

nlHostOutMacNonUnicastPkts OBJECT-TYPE
    SYNTAX      ZeroBasedCounter32
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The number of packets without errors transmitted by this
        address that were directed to any MAC broadcast addresses
        or to any MAC multicast addresses since this host was
        added to the nlHostTable.  Note that this is the number of
        link-layer packets, so if a single network-layer packet is
        fragmented into several link-layer frames, this counter is
        incremented several times."
    ::= { nlHostEntry 7 }

nlHostCreateTime OBJECT-TYPE
    SYNTAX     LastCreateTime
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The value of sysUpTime when this entry was last activated.
        This can be used by the management station to ensure that the
        entry has not been deleted and recreated between polls."
    ::= { nlHostEntry 8 }

-- -- Network Layer Matrix Group -- -- Counts the amount of traffic sent between each pair of network -- addresses discovered by the probe. -- Note that while the hlMatrixControlTable also has objects that -- control optional alMatrixTables, implementation of the -- alMatrixTables is not required to fully implement this group.

hlMatrixControlTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF HlMatrixControlEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A list of higher-layer (i.e., non-MAC) matrix control entries.

        These entries will enable the collection of the network- and
        application-level matrix tables containing conversation
        statistics indexed by pairs of network addresses.
        Both the network- and application-level matrix tables are
        controlled by this table so that they will both be created
        and deleted at the same time, further increasing the ease with
        which they can be implemented as a single datastore.  (Note that
        if an implementation stores application-layer matrix records

        in memory, it can derive network-layer matrix records from
        them.)

        Entries in the nlMatrixSDTable and nlMatrixDSTable will be
        created on behalf of each entry in this table.  Additionally,
        if this probe implements the alMatrix tables, entries in the
        alMatrix tables will be created on behalf of each entry in
        this table."
    ::= { nlMatrix 1 }

hlMatrixControlEntry OBJECT-TYPE
    SYNTAX      HlMatrixControlEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "A conceptual row in the hlMatrixControlTable.

        An example of indexing of this entry is
        hlMatrixControlNlDroppedFrames.1"
    INDEX { hlMatrixControlIndex }
    ::= { hlMatrixControlTable 1 }

HlMatrixControlEntry ::= SEQUENCE {
    hlMatrixControlIndex                  Integer32,
    hlMatrixControlDataSource             DataSource,
    hlMatrixControlNlDroppedFrames        Counter32,
    hlMatrixControlNlInserts              Counter32,
    hlMatrixControlNlDeletes              Counter32,
    hlMatrixControlNlMaxDesiredEntries    Integer32,
    hlMatrixControlAlDroppedFrames        Counter32,
    hlMatrixControlAlInserts              Counter32,
    hlMatrixControlAlDeletes              Counter32,
    hlMatrixControlAlMaxDesiredEntries    Integer32,
    hlMatrixControlOwner                  OwnerString,
    hlMatrixControlStatus                 RowStatus
}

hlMatrixControlIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..65535)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "An index that uniquely identifies an entry in the
        hlMatrixControlTable.  Each such entry defines
        a function that discovers conversations on a particular
        interface and places statistics about them in the
        nlMatrixSDTable and the nlMatrixDSTable, and optionally the
        alMatrixSDTable and alMatrixDSTable, on behalf of this

        hlMatrixControlEntry."
    ::= { hlMatrixControlEntry 1 }

hlMatrixControlDataSource OBJECT-TYPE
    SYNTAX      DataSource
    MAX-ACCESS  read-create
    STATUS      current
    DESCRIPTION
        "The source of the data for the associated matrix tables.

        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
        hlMatrixControlStatus object is equal to active(1)."
    ::= { hlMatrixControlEntry 2 }

hlMatrixControlNlDroppedFrames OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
       "The total number of frames that were received by the probe
        and therefore not accounted for in the *StatsDropEvents, but
        that the probe chose not to count for this entry for
        whatever reason.  Most often, this event occurs when the probe
        is out of some resources and decides to shed load from this
        collection.

        This count does not include packets that were not counted
        because they had MAC-layer errors.

        Note that if the nlMatrixTables are inactive because no
        protocols are enabled in the protocol directory, this value
        should be 0.

        Note that, unlike the dropEvents counter, this number is the
        exact number of frames dropped."
    ::= { hlMatrixControlEntry 3 }

hlMatrixControlNlInserts OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The number of times an nlMatrix entry has been
        inserted into the nlMatrix tables.  If an entry is inserted,

        then deleted, and then inserted, this counter will be
        incremented by 2.  The addition of a conversation into both
        the nlMatrixSDTable and nlMatrixDSTable shall be counted as
        two insertions (even though every addition into one table must
        be accompanied by an insertion into the other).

        To allow for efficient implementation strategies, agents may
        delay updating this object for short periods of time.  For
        example, an implementation strategy may allow internal
        data structures to differ from those visible via SNMP for
        short periods of time.  This counter may reflect the internal
        data structures for those short periods of time.

        Note that the sum of then nlMatrixSDTable and nlMatrixDSTable
        sizes can be determined by subtracting
        hlMatrixControlNlDeletes from hlMatrixControlNlInserts."
    ::= { hlMatrixControlEntry 4 }

hlMatrixControlNlDeletes OBJECT-TYPE
    SYNTAX     Counter32
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
        "The number of times an nlMatrix entry has been
        deleted from the nlMatrix tables (for any reason).  If an
        entry is deleted, then inserted, and then deleted, this
        counter will be incremented by 2.  The deletion of a
        conversation from both the nlMatrixSDTable and nlMatrixDSTable
        shall be counted as two deletions (even though every deletion
        from one table must be accompanied by a deletion from the
        other).

        To allow for efficient implementation strategies, agents may
        delay updating this object for short periods of time.  For
        example, an implementation strategy may allow internal
        data structures to differ from those visible via SNMP for
        short periods of time.  This counter may reflect the internal
        data structures for those short periods of time