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#ident	"@(#)draft-ietf-entmib-entmib-02.txt	1.3	05/06/12 SMI"

Draft                          Entity MIB               January 22, 1996


                   <draft-ietf-entmib-entmib-02.txt>
                               Entity MIB

                            22 January 1996


                            Keith McCloghrie
                           Cisco Systems Inc.
                             kzm@cisco.com

                              Andy Bierman
                           Bierman Consulting
                           abierman@west.net





                          Status of this Memo

This document is an Internet-Draft.  Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, and
its working groups.  Note that other groups may also distribute working
documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time.  It is inappropriate to use Internet- Drafts as reference material
or to cite them other than as ``work in progress.''

To learn the current status of any Internet-Draft, please check the
``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow
Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe),
ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim).
















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1.  Introduction

This memo defines an experimental portion of the Management Information
Base (MIB) for use with network management protocols in the Internet
community.  In particular, it describes managed objects used for
managing multiple logical entities managed by a single SNMPv1 agent.












































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2.  The SNMPv1 Network Management Framework

The SNMPv1 Network Management Framework presently consists of two major
components.  They are:

o    RFC 1442 [1] which defines the SMI, the mechanisms used for
     describing and naming objects for the purpose of management.

o    STD 17, RFC 1213 [2] defines MIB-II, the core set of managed
     objects for the Internet suite of protocols.


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


2.1.  Object Definitions

Managed objects are accessed via a virtual information store, termed the
Management Information Base or MIB.  Objects in the MIB are defined
using the subset of Abstract Syntax Notation One (ASN.1) defined in the
SMI.  In particular, each object type is named by an OBJECT IDENTIFIER,
an administratively assigned name.  The object type together with an
object instance serves to uniquely identify a specific instantiation of
the object.  For human convenience, we often use a textual string,
termed the descriptor, to refer to the object type.
























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3.  Overview

There is a need for a standardized way of representing a single agent
which supports multiple instances of one MIB.  This is presently true
for at least 3 standard MIBs, and is likely to become true for more and
more MIBs as time passes.  For example:

   - multiple instances of a bridge supported within a single device
     having a single agent;

   - multiple repeaters supported by a single agent;

   - multiple OSPF backbone areas, each one operating as part of its own
     Autonomous System, and each identified by the same area-id (e.g.,
     0.0.0.0), supported inside a single router with one agent.

The fact that it is a single agent in each of these cases implies there
is some relationship which binds all of these entities together.
Effectively, there is some "overall" physical entity which houses the
sum of the things managed by that one agent, i.e., there are multiple
"logical" entities within a single physical entity.  Sometimes, the
overall physical entity contains multiple (smaller) physical entities
and each logical entity is associated with a particular physical entity.
Sometimes, the overall physical entity is a "compound" of multiple
physical entities (e.g., a stack of stackable hubs).

What is needed is a way to determine exactly what logical entities are
managed by the agent (either by SNMPv1 or SNMPv2), and thereby to be
able to communicate with the agent about a particular logical entity.
When different logical entities are associated with different physical
entities within the overall physical entity, it is also useful to be
able to use this information to distinguish between logical entities.

In these situations, there is no need for varbinds for multiple logical
entities to be referenced in the same SNMPv1 message (although that
might be useful in the future).  Rather, it is sufficient, and in some
situations preferable, to have the context/community in the message
identify the logical entity to which the varbinds apply.


3.1.  Terms

Some new terms are used throughout this document:







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   - Naming Scope
     A "naming scope" represents the set of information that may be
     potentially accessed through a single SNMPv1 operation. All
     instances within the naming scope share the same unique identifier
     space. For SNMPv1, a naming scope is identified by the value of the
     associated 'entLogicalCommunity' instance.

   - Logical Entity
     A managed system contains one or more logical entities, each
     represented by at most one instantiation of each of a particular
     set of MIB objects. A set of management functions is associated
     with each logical entity. Examples of logical entities include
     routers, bridges, print-servers, etc.

   - Physical Entity
     A "physical entity" or "physical component" represents an
     identifiable physical resource within a managed system. Zero or
     more logical entities may utilize a physical resource at any given
     time. It is an implementation-specific manner as to which physical
     components are represented by an agent in the EntPhysicalTable.
     Typically, physical resources (e.g. communications ports,
     backplanes, sensors, daughter-cards, power supplies, the overall
     chassis) which can be managed via functions associated with one or
     more logical entities are included in the MIB.

   - Containment Tree
     Each physical component may optionally be modeled as 'contained'
     within another physical component. A "containment-tree" is the
     conceptual sequence of entPhysicalIndex values which uniquely
     specifies the exact physical location of a physical component
     within the managed system. It is generated by 'following and
     recording' each 'entPhysicalContainedIn' instance 'up the tree
     towards the root', until a value of zero indicating no further
     containment is found.

     It is required that physical containment-trees retain their
     identity across reboots. Specifically, two identical hardware
     configurations should produce the same set of containment-trees for
     every corresponding entry in the entPhysicalTable (i.e. the same
     set of entPhysicalEntries with the same entPhysicalIndex values,

     Note that chassis slots, which are capable of accepting one or more
     module types from one or more vendors, are modeled as containers in
     this MIB. The value of entPhysicalContainedIn for a particular
     'module' entity (entPhysicalClass value of 'module(9)') should be





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     equal to an entPhysicalIndex that represents the parent 'container'
     entity (associated entPhysicalClass value of ('container(5)'). An
     agent should represent both empty and full containers in the
     entPhysicalTable.


3.2.  Relationship to Community Strings

For SNMPv1, distinguishing between different logical entities is one
(but not the only) purpose of the community string [6].  This is
accommodated by representing each community string as a logical entity.

Note that different logical entities may 'share' the same naming scope
(and therefore the same values of entLogicalCommunity). In such a case,
individual logical entities can be identified by examining the
sysORTable within the same naming scope.


3.3.  Relationship to Proxy Mechanisms

The Entity MIB is designed to allow functional component discovery.  The
administrative relationships between different logical entities are not
visible in any Entity MIB tables.

The management of administrative framework functions is not an explicit
goal of the Entity MIB WG at this time. This new area of functionality
may be revisited after some operational experience with the Entity MIB
is gained.


3.4.  Relationship to a Chassis MIB

Some readers may recall that a previous IETF working group attempted to
define a Chassis MIB.  No consensus was reached by that working group,
possibly because its scope was too broad.  As such, it is not the
purpose of this MIB to be a "Chassis MIB replacement", nor is it within
the scope of this MIB to contain all the information which might be
necessary to manage a "chassis".  On the other hand, the entities
represented by an implementation of this MIB might well be contained in
a chassis.










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3.5.  Relationship to the Interfaces MIB

The Entity MIB contains a mapping table identifying physical components
that have 'external values' (e.g. ifIndex) associated with them within a
given naming scope.  This table can be used to identify the physical
location of each interface in the ifTable. Since ifIndex values in
different contexts are not related to one another, the interface to
physical component associations are relative to a specific logical
entity within the agent.



3.6.  Relationship to the Other MIBs

The Entity MIB contains a mapping table identifying physical components
that have identifiers from other standard MIBs associated with them.
For example, this table can be used along with the physical mapping
table to identify the physical location of each repeater port in the
rptrPortTable, each bridge port in the dot1dBasePortTable, or each
ifIndex in the ifTable.


3.7.  Re-Configuration of Entities

All the MIB objects defined in this MIB have at most a read-only MAX-
ACCESS clause, i.e., none are write-able.  This is another conscious
decision by the authors to limit this MIB's scope.  It is possible that
this restriction could be lifted after implementation experience.


3.8.  MIB Structure

This MIB contains five tables: the entPhysicalTable and the
entLogicalTable each provide a list of entities. The entLPMappingTable
provides mappings between logical and physical entities. The
entAliasMappingTable provides mappings between physical components and
associated identifiers from other MIBs. For example, a physical repeater
port may be associated with an instance of 'rptrPortGroupIndex.1.5', or
'ifIndex.12', or both. The entPhysicalContainsTable provides efficient
discovery of the containment relationships of all physical entities
(also derivable from 'entPhysicalContainedIn' values).


The entPhysicalTable contains one row per physical entity, and should
always contains at least one row for an "overall" physical entity.  Each





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row is indexed by an arbitrary, small integer, and contains a
description and type of the physical entity.  It also optionally
contains the index number of another entPhysicalEntry indicating a
containment relationship between the two.


The entLogicalTable contains one row per logical entity.  Each row is
indexed by an arbitrary, small integer and contains a name, description,
and type of the logical entity. It also contains information to allow
SNMPv1 access to the MIB information for the logical entity.


The entLPMappingTable contains mappings between entLogicalIndex values
(logical entities) and entPhysicalIndex values (the physical components
supporting that entity). A logical entity can map to more than one
physical component, and more than one logical entity can map to (share)
the same physical component.


The entAliasMappingTable contains mappings between entLogicalIndex,
entPhysicalIndex pairs and 'alias' object identifier values.  This
allows resources managed with other MIBs (e.g. repeater ports, bridge
ports, physical and logical interfaces) to be identified in the physical
entity hierarchy. Note that each alias identifier is only relevant in a
particular naming scope.


The entPhysicalContainsTable contains simple mappings between
'entPhysicalContainedIn' values for each container/containee
relationship in the managed system. The indexing of this table allows an
NMS to quickly discover the 'entPhysicalIndex' values for all children
of a given physical entity.


3.9.  Multiple Agents

Even though a primary motivation for this MIB is to represent the
multiple logical entities supported by a single agent, it is also
possible to use it to represent multiple logical entities supported by
multiple agents (in the same "overall" physical entity).  Indeed, it is
implicit in the SNMPv1 architecture, that the number of agents is
transparent to a network management station.








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4.  Definitions

ENTITY-MIB DEFINITIONS ::= BEGIN

IMPORTS
    MODULE-IDENTITY, OBJECT-TYPE,
    experimental, NOTIFICATION-TYPE
        FROM SNMPv2-SMI
    DisplayString, AutonomousType, TruthValue
        FROM SNMPv2-TC
    TAddress
        FROM SNMPv2-PARTY-MIB
    MODULE-COMPLIANCE, OBJECT-GROUP
        FROM SNMPv2-CONF;

entityMIB MODULE-IDENTITY
    LAST-UPDATED "9601200000Z"
    ORGANIZATION "IETF ENTMIB Working Group"
    CONTACT-INFO
            "        Keith McCloghrie
                     Cisco Systems Inc.
                     170 West Tasman Drive
                     San Jose, CA 95134
                     408-526-5260
                     kzm@cisco.com

                     Andy Bierman
                     Bierman Consulting
                     1200 Sagamore Lane
                     Ventura, CA 93001
                     805-648-2028
                     abierman@west.net"
    DESCRIPTION
            "The MIB module for representing multiple logical
            entities supported by a single SNMP agent."
    ::= { experimental xx }

entityMIBObjects OBJECT IDENTIFIER ::= { entityMIB 1 }












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--           The Physical Entity Table

entPhysicalTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF EntPhysicalEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "This table contains one row per physical entity.  There is
            always at least one row for an 'overall' physical entity."
    ::= { entityMIBObjects 1 }

entPhysicalEntry       OBJECT-TYPE
    SYNTAX      EntPhysicalEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "Information about a particular physical entity.  An agent
            is expected to represent physical components in as much
            detail as possible.  If more than one agent within a chassis
            implements the Entity MIB, the information retrieved from
            each agent must be consistent, but not necessarily
            identical."
    INDEX   { entPhysicalIndex }
    ::= { entPhysicalTable 1 }

EntPhysicalEntry ::= SEQUENCE {
      entPhysicalIndex          INTEGER,
      entPhysicalDescr          DisplayString,
      entPhysicalVendorType     AutonomousType,
      entPhysicalContainedIn    INTEGER,
      entPhysicalClass          INTEGER,
      entPhysicalParentRelPos   INTEGER
}

entPhysicalIndex    OBJECT-TYPE
    SYNTAX      INTEGER (1..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "The value of this object uniquely identifies the physical
            entity.  The value is a small positive integer; index values
            for different physical entities are not necessarily
            contiguous."
    ::= { entPhysicalEntry 1 }






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entPhysicalDescr OBJECT-TYPE
    SYNTAX      DisplayString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "A textual description of physical entity."
    ::= { entPhysicalEntry 2 }

entPhysicalVendorType OBJECT-TYPE
    SYNTAX      AutonomousType
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "An indication of the vendor-specific hardware type of the
            physical entity. Note that this is different from the
            definition of MIB-II's sysObjectID.

            An agent should set this object to a enterprise-specific
            registration identifier value indicating the specific
            equipment type in detail.  The associated instance of
            entPhysicalClass should be used to indicate the general type
            of hardware device.

            If no vendor-specific registration identifier exists for
            this physical entity, then the value { 0 0 } is returned. If
            the value is unknown by this agent, then the special value
            'entPClassUnknown' is returned."
    ::= { entPhysicalEntry 3 }

entPhysicalContainedIn OBJECT-TYPE
    SYNTAX      INTEGER (0..2147483647)
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The value of entPhysicalIndex for the physical entity which
            'contains' this physical entity.  A value of zero indicates
            this physical entity is not contained in any other physical
            entity.  Note that the set of 'containment' relationships
            define a strict hierarchy; that is, recursion is not
            allowed."
    ::= { entPhysicalEntry 4 }

entPhysicalClass OBJECT-TYPE
    SYNTAX      INTEGER  {
        other(1),





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        unknown(2),
        chassis(3),
        backplane(4),
        container(5),   -- slot or daughter-card holder
        powerSupply(6),
        fan(7),
        sensor(8),
        module(9),      -- plug-in card  or daughter-card
        port(10)
    }
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "An indication of the general hardware type of the physical
            entity.

            An agent should set this object to the standard enumeration
            value which most accurately indicates the general class of
            the physical entity, or the primary class if there is more
            than one.

            If no appropriate standard registration identifier exists
            for this physical entity, then the value 'other(1)' is
            returned. If the value is unknown by this agent, then the
            value 'unknown(2)' is returned."
    ::= { entPhysicalEntry 5 }

entPhysicalParentRelPos OBJECT-TYPE
    SYNTAX      INTEGER (0..2147483647)
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "An indication of the position of this 'child' component
            among all its 'sibling' components. The numbering is
            relative to the 'parent' component. A component's parent is
            identified by the associated instance of the
            entPhysicalContainedIn object.  An NMS may use this value to
            compare against other entPhysicalEntries with the same
            parent (same value of entPhysicalContainedIn).

            This value should match any external labeling of the
            physical component if possible. For example, an
            entPhysicalEntry representing entPhysicalParentRelPos value
            of '10'. The entPhysicalContainedIn instance should equal
            the entPhysicalIndex for the parent (module 3). The





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            entPhysicalParentRelPos instance associated with the parent
            should be equal to '3'.

            If the physical position of this component does not match
            any external labeling, then user documentation or other
            external reference material should be used to determine the
            parent-relative position. If this is not possible, then the
            the agent should assign an arbitrary ordering to a given set
            of 'sibling' components, perhaps based on internal
            representation of the components.

            If the agent cannot determine the parent-relative position
            for some reason, or if the associated value of
            entPhysicalContainedIn is '0', then the value '0' is
            returned. Otherwise a positive integer is returned,
            indicating the parent-relative position of this physical
            entity.

            Parent-relative ordering should start from '1' and continue
            to 'N', where 'N' represents the highest positioned child
            entity. Note that this ordering may be sparse or dense,
            depending on agent implementation.  The actual values
            returned are not globally meaningful, as each 'parent'
            component may use different numbering algorithms. The
            ordering is only meaningful among siblings of the same
            parent component.

            The agent should retain parent-relative position values
            across reboots, either through algorithmic assignment or use
            of non-volatile storage."
    ::= { entPhysicalEntry 6 }



















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--           The Logical Entity Table
entLogicalTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF EntLogicalEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "This table contains one row per logical entity."
    ::= { entityMIBObjects 2 }

entLogicalEntry       OBJECT-TYPE
    SYNTAX      EntLogicalEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "Information about a particular logical entity.  Entities
            may be managed by this agent or other SNMP agents (possibly)
            in the same chassis."
    INDEX       { entLogicalIndex }
    ::= { entLogicalTable 1 }

EntLogicalEntry ::= SEQUENCE {
      entLogicalIndex            INTEGER,
      entLogicalDescr            DisplayString,
      entLogicalType             AutonomousType,
      entLogicalCommunity        OCTET STRING,
      entLogicalTAddress         TAddress,
      entLogicalTDomain          OBJECT IDENTIFIER
}

entLogicalIndex OBJECT-TYPE
    SYNTAX      INTEGER (1..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "The value of this object uniquely identifies the logical
            entity. The value is a small positive integer; index values
            for different logical entities are are not necessarily
            contiguous."
    ::= { entLogicalEntry 1 }











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entLogicalDescr OBJECT-TYPE
    SYNTAX      DisplayString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "A textual description of logical entity."
    ::= { entLogicalEntry 2 }

entLogicalType OBJECT-TYPE
    SYNTAX      AutonomousType
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "An indication of the type of logical entity.  This will
            typically be the OBJECT IDENTIFIER name of the node in the
            SMI's naming hierarchy which represents the major MIB
            module, or the majority of the MIB modules, supported by the
            logical entity.  For example:
               a logical entity of a regular host/router -> mib-2
               a logical entity of a 802.1d bridge     -> dot1dBridge
               a logical entity of a 802.3 repeater  ->
            snmpDot3RptrMgmt"
    ::= { entLogicalEntry 3 }

entLogicalCommunity OBJECT-TYPE
    SYNTAX      OCTET STRING
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "A SNMPv1 community-string which can be used to access
            detailed management information for this logical entity.
            The agent should allow read access with this community
            string (to an appropriate subset of all managed objects) and
            may also choose to return a community string based on the
            privileges of the request used to read this object (e.g.
            only return a string having read-write privileges when
            accessed with read-write privileges).

            A conformant SNMP agent may wish to conserve naming scopes
            by representing multiple logical entities in a single 'main'
            naming scope.  This is possible when the logical entities
            represented by the same value of entLogicalCommunity have no
            object instances in common.  For example, 'bridge1' and
            'repeater1' may be part of the main naming scope, but two
            additional community strings are needed to represent





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            'bridge2' and 'repeater2'.

            Logical entities 'bridge1' and 'repeater1' would be
            represented by sysOREntries associated with the 'main'
            naming scope.

            For agents not accessible via SNMPv1, the value of this
            object is the empty-string."
    ::= { entLogicalEntry 4 }


entLogicalTAddress OBJECT-TYPE
    SYNTAX      TAddress
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The transport service address by which the logical entity
            receives network management traffic, formatted according to
            the corresponding value of entLogicalTDomain. For
            snmpUDPDomain, entLogicalTAddress is formatted as a 4-octet
            IP Address concatenated with a 2-octet UDP port number."
    ::= { entLogicalEntry 5 }

entLogicalTDomain OBJECT-TYPE
    SYNTAX      OBJECT IDENTIFIER
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "Indicates the kind of transport service by which the
            logical entity receives network management traffic.
            Possible values for this object are presently found in the
            Transport Mappings for SNMPv2 document (RFC 1449 [8]).  [ed
            -- RFC 1449 is now historic]"
    ::= { entLogicalEntry 6 }
















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--   entLPMappingTable: for each entity index, there are N
--      rows, each representing a physical component
--      that is associated with the indicated entity
--
-- entity to component table
entLPMappingTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF EntLPMappingEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "This table contains zero or more rows of logical entity to
            physical equipment associations."
    ::= { entityMIBObjects 3 }

entLPMappingEntry       OBJECT-TYPE
    SYNTAX      EntLPMappingEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "Information about a particular logical entity to physical
            equipment binding."
    INDEX       { entLogicalIndex, entLPPhysicalIndex }
    ::= { entLPMappingTable 1 }

EntLPMappingEntry ::= SEQUENCE {
      entLPPhysicalIndex         INTEGER
}

entLPPhysicalIndex OBJECT-TYPE
    SYNTAX      INTEGER (1..2147483647)
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The value of this object identifies a particular
            entPhysicalEntry associated with the indicated
            entLogicalEntity."
    ::= { entLPMappingEntry 1 }













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-- logical entity/component to alias table
entAliasMappingTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF EntAliasMappingEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "This table contains zero or more rows of logical entity,
            and physical component to external identifier associations."
    ::= { entityMIBObjects 4 }

entAliasMappingEntry       OBJECT-TYPE
    SYNTAX      EntAliasMappingEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "Information about a particular physical equipment, logical
            entity to external identifier binding. Note that the same
            logical entity/ physical component pair may have an
            arbitrary number of external identifier (alias) bindings."
    INDEX { entLogicalIndex, entPhysicalIndex, entAliasMappingIndex }
    ::= { entAliasMappingTable 1 }

EntAliasMappingEntry ::= SEQUENCE {
      entAliasMappingIndex      INTEGER,
      entAliasIdentifier        OBJECT IDENTIFIER
}

entAliasMappingIndex OBJECT-TYPE
    SYNTAX      INTEGER (1..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "The value of this object uniquely identifies the particular
            binding for a specific logical entity on a particular
            physical component. The value is a small positive integer;
            index values for different entAlias mappings are not
            necessarily contiguous."
    ::= { entAliasMappingEntry 1 }

entAliasIdentifier OBJECT-TYPE
    SYNTAX      OBJECT IDENTIFIER
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The value of this object identifies a particular MIB





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            instance associated with the indicated entPhysicalEntry and
            entLogicalEntry pair.

            For example, suppose a physical port was represented by
            entPhysicalEntry.3, and entLogicalEntry.1 existed for a
            repeater, entLogicalEntry.2 existed for a bridge, and the
            bridge port was also represented in the ifTable. Then there
            might be three related instances of entAliasIdentifier:
               entAliasIdentifier.3.1.1 == rptrPortGroupIndex.5.2
               entAliasIdentifier.3.2.1 == dot1dBasePort.2
               entAliasIdentifier.3.2.2 == ifIndex.2 "
    ::= { entAliasMappingEntry 2 }






































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-- physical mapping table
entPhysicalContainsTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF EntPhysicalContainsEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "A table which exposes the container/containee relationships
            between physical entities."
    ::= { entityMIBObjects 5 }

entPhysicalContainsEntry OBJECT-TYPE
    SYNTAX      EntPhysicalContainsEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "A single container/containee relationship."
    INDEX       { entPhysicalIndex, entPhysicalChildIndex }
    ::= { entPhysicalContainsTable 1 }

EntPhysicalContainsEntry ::= SEQUENCE {
      entPhysicalChildIndex INTEGER
}

entPhysicalChildIndex OBJECT-TYPE
    SYNTAX      INTEGER (1..2147483647)
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The value of entPhysicalIndex for the contained physical
            entity."
    ::= { entPhysicalContainsEntry 1 }



















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-- last change timestamp for the whole MIB
entLastChangeTime OBJECT-TYPE
    SYNTAX      Timestamp
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The value of sysUpTime at the time any of these events
            occur:
                * a conceptual row is created or deleted in any of these tables:
                    - entPhysicalTable
                    - entLogicalTable
                    - entLPMappingTable
                    - entAliasMappingTable
                    - entPhysicalContainsTable

                * any instance in the following list of objects changes value:
                    - entPhysicalDescr
                    - entPhysicalVendorType
                    - entPhysicalContainedIn
                    - entPhysicalClass
                    - entLogicalDescr
                    - entLogicalType
                    - entLogicalCommunity
                    - entLogicalTAddress
                    - entLogicalTDomain
                    - entAliasIdentifier
            "
    ::= { entityMIBObjects 6 }






















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-- Entity MIB Trap Definitions
entityMIBTraps    OBJECT IDENTIFIER ::= { entityMIB 2 }

entConfigChange NOTIFICATION-TYPE
    OBJECTS {
            entLastChangeTime
            }
    STATUS             current
    DESCRIPTION
            "An entConfigChange trap is sent when the value of
            entLastChangeTime changes. It can be utilized by an NMS to
            trigger logical/physical entity table maintenance polls.
            This trap is throttled by the agent.

            The value of entLastChangeTime at the time the
            entConfigChange event is detected by the agent is encoded as
            a var-bind in the trap. This should be the same value as the
            sysUpTime instance included in the trap, but may not be if
            trap generation is delayed at all within the agent.

            An agent must take care not to generate more than one
            entConfigChange 'trap-event' in a five second period, where
            a 'trap-event' is the transmission of a single trap PDU to a
            list of trap destinations.  If additional configuration
            changes occur within the five second 'throttling' period,
            then these events should be discarded by the agent. An NMS
            should periodically check the value of entLastChangeTime to
            detect any missed entConfigChange events due to throttling.
   ::= { entityMIBTraps 1 }





















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-- conformance information
entityConformance OBJECT IDENTIFIER ::= { entityMIB 3 }

entityCompliances OBJECT IDENTIFIER ::= { entityConformance 1 }
entityGroups      OBJECT IDENTIFIER ::= { entityConformance 2 }

-- compliance statements

entityCompliance MODULE-COMPLIANCE
    STATUS  current
    DESCRIPTION
            "The compliance statement for SNMPv2 entities
            which implement the Entity MIB."
    MODULE  -- this module
        MANDATORY-GROUPS { entityGroup }
    ::= { entityCompliances 1 }


-- units of conformance

entityGroup    OBJECT-GROUP
    OBJECTS { entPhysicalDescr,
              entPhysicalVendorType,
              entPhysicalContainedIn,
              entPhysicalClass,
              entPhysicalParentRelPos,
              entLogicalDescr,
              entLogicalType,
              entLogicalCommunity,
              entLogicalTAddress,
              entLogicalTDomain,
              entLPPhysicalIndex,
              entAliasIdentifier,
              entPhysicalChildIndex,
              entLastChangeTime,
              entConfigChange
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects which are used to
            represent the multiple logical entities,
            physical components, interfaces, and port
            alias identifiers for which a single agent
            provides MIB information."
    ::= { entityGroups 1 }





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END

















































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5.  Usage Examples

The following sections iterate the instance values for two example
networking devices. These examples are kept simple to make them more
understandable. Auxillary components, such as fans, sensors, empty
slots, and sub-modules are not shown, but should be modeled in real
implementations.


5.1.  Router/Bridge

An SNMPv1 router containing two slots.  Each slot contains a 3 port
router/bridge module. Each port is represented in the ifTable.  There
are two logical instances of OSPF running and two logical bridges:

  Physical entities -- entPhysicalTable:
    1 Field-replaceable physical chassis:
      entPhysicalDescr.1 ==             "Acme Chassis Model 100"
      entPhysicalVendorType.1  ==       acmeProducts.chassisTypes.1
      entPhysicalContainedIn.1 ==       0
      entPhysicalClass.1 ==             chassis(3)
      entPhysicalParentRelPos.1 ==      0

    2 slots within the chassis:
      entPhysicalDescr.2 ==             "Acme Router Chassis Slot 1"
      entPhysicalVendorType.2  ==       acmeProducts.slotTypes.1
      entPhysicalContainedIn.2 ==       1
      entPhysicalClass.2 ==             container(5)
      entPhysicalParentRelPos.2 ==      1

      entPhysicalDescr.3 ==             "Acme Router Chassis Slot 2"
      entPhysicalVendorType.3  ==       acmeProducts.slotTypes.1
      entPhysicalContainedIn.3 ==       1
      entPhysicalClass.3 ==             container(5)
      entPhysicalParentRelPos.3 ==      2

    2 Field-replaceable modules:
    Slot 1 contains a module with 3 ports:
      entPhysicalDescr.4 ==             "Acme Router Module Model 10"
      entPhysicalVendorType.4  ==       acmeProducts.moduleTypes.14
      entPhysicalContainedIn.4 ==       2
      entPhysicalClass.4 ==             module(9)
      entPhysicalParentRelPos.4 ==      1

      entPhysicalDescr.5 ==             "Acme Router Ethernet Port 1"





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      entPhysicalVendorType.5  ==       acmeProducts.portTypes.2
      entPhysicalContainedIn.5 ==       4
      entPhysicalClass.5 ==             port(10)
      entPhysicalParentRelPos.5 ==      1

      entPhysicalDescr.6 ==             "Acme Router Ethernet Port 2"
      entPhysicalVendorType.6  ==       acmeProducts.portTypes.2
      entPhysicalContainedIn.6 ==       4
      entPhysicalClass.6 ==             port(10)
      entPhysicalParentRelPos.6 ==      2

      entPhysicalDescr.7 ==             "Acme Router Fddi Port 3"
      entPhysicalVendorType.7  ==       acmeProducts.portTypes.3
      entPhysicalContainedIn.7 ==       4
      entPhysicalClass.7 ==             port(10)
      entPhysicalParentRelPos.7 ==      3

   Slot 2 contains another 3-port module:
      entPhysicalDescr.8 ==             "Acme Router Module Model 11"
      entPhysicalVendorType.8  ==       acmeProducts.moduleTypes.15
      entPhysicalContainedIn.8 ==       3
      entPhysicalClass.8 ==             module(9)
      entPhysicalParentRelPos.8 ==      1

      entPhysicalDescr.9 ==             "Acme Router Fddi Port 1"
      entPhysicalVendorType.9 ==        acmeProducts.portTypes.3
      entPhysicalContainedIn.9 ==       8
      entPhysicalClass.9 ==             port(10)
      entPhysicalParentRelPos.9 ==      1

      entPhysicalDescr.10 ==            "Acme Router Ethernet Port 2"
      entPhysicalVendorType.10 ==       acmeProducts.portTypes.2
      entPhysicalContainedIn.10 ==      8
      entPhysicalClass.10 ==            port(10)
      entPhysicalParentRelPos.10 ==     2

      entPhysicalDescr.11 ==            "Acme Router Ethernet Port 3"
      entPhysicalVendorType.11 ==       acmeProducts.portTypes.2
      entPhysicalContainedIn.11 ==      8
      entPhysicalClass.11 ==            port(10)
      entPhysicalParentRelPos.11 ==     3

   Logical entities -- entLogicalTable
   2 OSPF instances:
      entLogicalDescr.1 ==            "ospf-1"





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      entLogicalType.1 ==             ospf
      entLogicalCommunity.1 ==        "public-ospf1"
      entLogicalTAddress.1 ==         124.125.126.127:161
      entLogicalTDomain.1 ==          snmpUDPDomain

      entLogicalDescr.2 ==            "ospf-2"
      entLogicalType.2 ==             ospf
      entLogicalCommunity.2 ==        "public-ospf2"
      entLogicalTAddress.2 ==         124.125.126.127:161
      entLogicalTDomain.2 ==          snmpUDPDomain

    2 logical bridges:
      entLogicalDescr.3 ==            "bridge1"
      entLogicalType.3  ==            dod1dBridge
      entLogicalCommunity.3 ==        "public-bridge1"
      entLogicalTAddress.3 ==         124.125.126.127:161
      entLogicalTDomain.3 ==          snmpUDPDomain

      entLogicalDescr.4 ==            "bridge2"
      entLogicalType.4 ==             dod1dBridge
      entLogicalCommunity.4 ==        "public-bridge2"
      entLogicalTAddress.4 ==         124.125.126.127:161
      entLogicalTDomain.4 ==          snmpUDPDomain

Logical to Physical Mappings:
  1st OSPF instance: uses module 1-port 1
      entLPPhysicalIndex.1.5 ==         5

  2nd OSPF instance: uses module 2-port 1
      entLPPhysicalIndex.2.9 ==         9

  1st bridge group: uses module 1, all ports
      entLPPhysicalIndex.3.5 ==         5
      entLPPhysicalIndex.3.6 ==         6
      entLPPhysicalIndex.3.7 ==         7

  2nd bridge group: uses module 2, all ports
      entLPPhysicalIndex.4.9  ==        9
      entLPPhysicalIndex.4.10 ==        10
      entLPPhysicalIndex.4.11 ==        11

Logical to Physical to Alias Mappings -- entAliasMappingTable:
  Bridge 1 uses Ports 1..3 on Slot 1
      entAliasIdentifier.3.5.1 ==       dot1dBasePort.1
      entAliasIdentifier.3.5.2 ==       ifIndex.1





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      entAliasIdentifier.3.6.1 ==       dot1dBasePort.2
      entAliasIdentifier.3.6.2 ==       ifIndex.2
      entAliasIdentifier.3.7.1 ==       dot1dBasePort.3
      entAliasIdentifier.3.7.2 ==       ifIndex.3

  Bridge 2 uses Ports 1..3 on Slot 2; uses same Bridge MIB and ifIndex
  values as Bridge 1, but in a different context, and representing
  different physical ports:
      entAliasIdentifier.4.9.1 ==       dot1dBasePort.1
      entAliasIdentifier.4.9.2 ==       ifIndex.1
      entAliasIdentifier.4.10.1 ==      dot1dBasePort.2
      entAliasIdentifier.4.10.2 ==      ifIndex.2
      entAliasIdentifier.4.11.1 ==      dot1dBasePort.3
      entAliasIdentifier.4.11.2 ==      ifIndex.3

Physical Containment Tree -- entPhysicalContainsTable
  chassis has two containers:
      entPhysicalChildIndex.1.2 = 2
      entPhysicalChildIndex.1.3 = 3

  container 1 has a module:
      entPhysicalChildIndex.2.4 = 4

  container 2 has a module
      entPhysicalChildIndex.3.8 = 8

  module 1 has some ports:
      entPhysicalChildIndex.4.5 = 5
      entPhysicalChildIndex.4.6 = 6
      entPhysicalChildIndex.4.7 = 7

  module 2 has some ports:
      entPhysicalChildIndex.8.9 = 9
      entPhysicalChildIndex.8.10 = 10
      entPhysicalChildIndex.1.11 = 11


5.2.  Repeaters

An SNMPv1 only, 3-slot Hub with 2 backplane ethernet segments.  Slot
three is empty, and the remaining slots contain ethernet repeater
modules.

   Physical entities -- entPhysicalTable:
    1 Field-replaceable physical chassis:





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      entPhysicalDescr.1 ==          "Acme Repeater Chassis Model 110"
      entPhysicalVendorType.1 ==     acmeProducts.chassisTypes.2
      entPhysicalContainedIn.1 ==    0
      entPhysicalClass.1 ==          chassis(3)
      entPhysicalParentRelPos.1 ==   0

    2 Chassis Ethernet Backplanes:
      entPhysicalDescr.2 ==          "Ethernet Backplane 1"
      entPhysicalVendorType.2 ==     acmeProducts.backplaneTypes.1
      entPhysicalContainedIn.2 ==    1
      entPhysicalClass.2 ==          backplane(4)
      entPhysicalParentRelPos.2 ==   1

      entPhysicalDescr.3 ==          "Ethernet Backplane 2"
      entPhysicalVendorType.3  ==    acmeProducts.backplaneTypes.1
      entPhysicalContainedIn.3 ==    1
      entPhysicalClass.3 ==          backplane(4)
      entPhysicalParentRelPos.3 ==   2

     3 slots within the chassis:
      entPhysicalDescr.4 ==          "Acme Hub Slot 1"
      entPhysicalVendorType.4  ==    acmeProducts.slotTypes.5
      entPhysicalContainedIn.4 ==    1
      entPhysicalClass.4 ==          container(5)
      entPhysicalParentRelPos.4 ==   1

      entPhysicalDescr.5 ==          "Acme Hub Slot 2"
      entPhysicalVendorType.5  ==    acmeProducts.slotTypes.5
      entPhysicalContainedIn.5 ==    1
      entPhysicalClass.5 ==          container(5)
      entPhysicalParentRelPos.5 ==   2

      entPhysicalDescr.6 ==          "Acme Hub Slot 3"
      entPhysicalVendorType.6  ==    acmeProducts.slotTypes.5
      entPhysicalContainedIn.6 ==    1
      entPhysicalClass.6 ==          container(5)
      entPhysicalParentRelPos.6 ==   3

    Slot 1 contains a plug-in module with 4 10-BaseT ports:
      entPhysicalDescr.7  ==         "10Base-T Module Model 14"
      entPhysicalVendorType.7   ==   acmeProducts.moduleTypes.32
      entPhysicalContainedIn.7  ==   4
      entPhysicalClass.7 ==          module(9)
      entPhysicalParentRelPos.7 ==   1






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      entPhysicalDescr.8  ==         "10Base-T Port 1"
      entPhysicalVendorType.8   ==   acmeProducts.portTypes.10
      entPhysicalContainedIn.8  ==   7
      entPhysicalClass.8 ==          port(10)
      entPhysicalParentRelPos.8 ==   1

      entPhysicalDescr.9  ==         "10Base-T Port 2"
      entPhysicalVendorType.9   ==   acmeProducts.portTypes.10
      entPhysicalContainedIn.9  ==   7
      entPhysicalClass.9 ==          port(10)
      entPhysicalParentRelPos.9 ==   2

      entPhysicalDescr.10 ==         "10Base-T Port 3"
      entPhysicalVendorType.10  ==   acmeProducts.portTypes.10
      entPhysicalContainedIn.10 ==   7
      entPhysicalClass.10 ==         port(10)
      entPhysicalParentRelPos.10 ==  3

      entPhysicalDescr.11 ==         "10Base-T Port 4"
      entPhysicalVendorType.11  ==   acmeProducts.portTypes.10
      entPhysicalContainedIn.11 ==   7
      entPhysicalClass.11 ==         port(10)
      entPhysicalParentRelPos.11 ==  4

   Slot 2 contains another ethernet module with 2 ports.
      entPhysicalDescr.12 ==         "Acme 10Base-T Module Model 4"
      entPhysicalVendorType.12 ==    acmeProducts.moduleTypes.30
      entPhysicalContainedIn.12 =    5
      entPhysicalClass.12 ==         module(9)
      entPhysicalParentRelPos.12 ==  1

      entPhysicalDescr.13 ==         "802.3 AUI Port 1"
      entPhysicalVendorType.13  ==   acmeProducts.portTypes.11
      entPhysicalContainedIn.13 ==   12
      entPhysicalClass.13 ==         port(10)
      entPhysicalParentRelPos.13 ==  1

      entPhysicalDescr.14 ==         "10Base-T Port 2"
      entPhysicalVendorType.14  ==   acmeProducts.portTypes.10
      entPhysicalContainedIn.14 ==   12
      entPhysicalClass.14 ==         port(10)
      entPhysicalParentRelPos.14 ==  2

   Logical entities -- entLogicalTable
     Repeater 1--comprised of any ports attached to backplane 1





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      entLogicalDescr.1 ==         "repeater1"
      entLogicalType.1  ==         snmpDot3RptrMgt
      entLogicalCommunity.1        "public-repeater1"
      entLogicalTAddress.1 ==      124.125.126.127:161
      entLogicalTDomain.1 ==       snmpUDPDomain

     Repeater 2--comprised of any ports attached to backplane 2:
      entLogicalDescr.2 ==         "repeater2"
      entLogicalType.2  ==         snmpDot3RptrMgt
      entLogicalCommunity.2 ==     "public-repeater2"
      entLogicalTAddress.2 ==      124.125.126.127:161
      entLogicalTDomain.2 ==       snmpUDPDomain

Logical to Physical Mappings -- entLPMappingTable:

  repeater1 uses backplane 1, slot 1-ports 1 & 2, slot 2-port 1
     entLPPhysicalIndex.1.2 ==          2
     entLPPhysicalIndex.1.8 ==          8
     entLPPhysicalIndex.1.9 ==          9
     entLPPhysicalIndex.1.13 ==         13

  repeater2 uses backplane 2, slot 1-ports 3 & 4, slot 2-port 2
      entLPPhysicalIndex.2.3 ==         3
      entLPPhysicalIndex.2.10 ==        10
      entLPPhysicalIndex.2.11 ==        11
      entLPPhysicalIndex.2.14 ==        14

Logical to Physical to Alias Mappings -- entAliasMappingTable:
  repeater1 uses slot 1-ports 1 & 2, slot 2-port 1
      entAliasIdentifier.1.8.1 ==       rptrPortGroupIndex.1.1
      entAliasIdentifier.1.9.1 ==       rptrPortGroupIndex.1.2
      entAliasIdentifier.1.13.1 ==      rptrPortGroupIndex.2.1

  repeater2 uses slot 1-ports 3 & 4, slot 2-port 2
      entAliasIdentifier.2.10.1 ==      rptrPortGroupIndex.1.3
      entAliasIdentifier.2.11.1 ==      rptrPortGroupIndex.1.4
      entAliasIdentifier.2.14.1 ==      rptrPortGroupIndex.2.2

Physical Containment Tree -- entPhysicalContainsTable

  chassis has two backplanes and three containers:
      entPhysicalChildIndex.1.2 = 2
      entPhysicalChildIndex.1.3 = 3
      entPhysicalChildIndex.1.4 = 4
      entPhysicalChildIndex.1.5 = 5





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      entPhysicalChildIndex.1.6 = 6

  container 1 has a module:
      entPhysicalChildIndex.4.7 = 7

  container 2 has a module
      entPhysicalChildIndex.5.12 = 12
  -- container 3 is empty

  module 1 has some ports:
      entPhysicalChildIndex.7.8 = 8
      entPhysicalChildIndex.7.9 = 9
      entPhysicalChildIndex.7.10 = 10
      entPhysicalChildIndex.7.11 = 11

  module 2 has some ports:
      entPhysicalChildIndex.12.13 = 13
      entPhysicalChildIndex.12.14 = 14
































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6.  Acknowledgements

This document was produced by the IETF Entity MIB Working Group.















































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7.  References

[1]  Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Structure
     of Management Information for version 2 of the Simple Network
     Management Protocol (SNMPv2)", RFC 1442, SNMP Research,Inc., Hughes
     LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon
     University, April 1993.

[2]  McCloghrie, K., and M. Rose, Editors, "Management Information Base
     for Network Management of TCP/IP-based internets: MIB-II", STD 17,
     RFC 1213, Hughes LAN Systems, Performance Systems International,
     March 1991.

[3]  Galvin, J., and K. McCloghrie, "Administrative Model for version 2
     of the Simple Network Management Protocol (SNMPv2)", RFC 1445,
     Trusted Information Systems, Hughes LAN Systems, April 1993.

[4]  Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol
     Operations for version 2 of the Simple Network Management Protocol
     (SNMPv2)", RFC 1448, SNMP Research,Inc., Hughes LAN Systems, Dover
     Beach Consulting, Inc., Carnegie Mellon University, April 1993.

[5]  McCloghrie, K., and J.  Galvin, "Party MIB for Version 2 of the
     Simple Network Management Protocol (SNMPv2)", RFC 1447, Hughes LAN
     Systems, Trusted Information Systems, April 1993.

[6]  Case, J., M. Fedor, M. Schoffstall, J. Davin, "Simple Network
     Management Protocol", RFC 1157, SNMP Research, Performance Systems
     International, MIT Laboratory for Computer Science, May 1990.

[7]  McCloghrie, K., and Kastenholtz, F., "Interfaces Group Evolution",
     RFC 1573, Hughes LAN Systems, FTP Software, January 1994.

[8]  Case, J., McCloghrie, K., Rose, M., and Waldbusser, S., "Transport
     Mappings for version 2 of the Simple Network Management Protocol
     (SNMPv2)", RFC 1449, SNMP Research, Inc., Hughes LAN Systems, Dover
     Beach Consulting, Inc., Carnegie Mellon University, April 1993.













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8.  Security Considerations

Security issues are not discussed in this memo.


9.  Authors' Addresses

     Keith McCloghrie
     cisco Systems, Inc.
     170 West Tasman Drive
     San Jose, CA 95134
     Phone: 408-526-5260
     Email: kzm@cisco.com

     Andy Bierman
     Bierman Consulting
     1200 Sagamore Lane
     Ventura, CA 93001
     Phone: 805-648-2028
     Email: abierman@west.net






























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Table of Contents


1 Introduction ....................................................    2
2 The SNMPv1 Network Management Framework .........................    3
2.1 Object Definitions ............................................    3
3 Overview ........................................................    4
3.1 Terms .........................................................    4
3.2 Relationship to Community Strings .............................    6
3.3 Relationship to Proxy Mechanisms ..............................    6
3.4 Relationship to a Chassis MIB .................................    6
3.5 Relationship to the Interfaces MIB ............................    7
3.6 Relationship to the Other MIBs ................................    7
3.7 Re-Configuration of Entities ..................................    7
3.8 MIB Structure .................................................    7
3.9 Multiple Agents ...............................................    8
4 Definitions .....................................................    9
5 Usage Examples ..................................................   25
5.1 Router/Bridge .................................................   25
5.2 Repeaters .....................................................   28
6 Acknowledgements ................................................   33
7 References ......................................................   34
8 Security Considerations .........................................   35
9 Authors' Addresses ..............................................   35


























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