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RFC 4133 - Entity MIB (Version 3)


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Network Working Group                                         A. Bierman
Request for Comments: 4133                                 K. McCloghrie
Obsoletes: 2737                                      Cisco Systems, Inc.
Category: Standards Track                                    August 2005

                         Entity MIB (Version 3)

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 (C) The Internet Society (2005).

Abstract

   This memo defines a 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 and physical entities managed by a single SNMP
   agent.  This document specifies version 3 of the Entity MIB, which
   obsoletes version 2 (RFC 2737).

Table of Contents

   1. The SNMP Management Framework ...................................3
   2. Overview ........................................................3
      2.1. Terms ......................................................4
      2.2. Relationship to Community Strings ..........................5
      2.3. Relationship to SNMP Contexts ..............................5
      2.4. Relationship to Proxy Mechanisms ...........................6
      2.5. Relationship to a Chassis MIB ..............................6
      2.6. Relationship to the Interfaces MIB .........................6
      2.7. Relationship to the Other MIBs .............................7
      2.8. Relationship to Naming Scopes ..............................7
      2.9. Multiple Instances of the Entity MIB .......................7
      2.10. Re-Configuration of Entities ..............................8
      2.11. Textual Convention Change .................................8
      2.12. MIB Structure .............................................8
            2.12.1. entityPhysical Group ..............................9
            2.12.2. entityLogical Group ..............................11
            2.12.3. entityMapping Group ..............................11
            2.12.4. entityGeneral Group ..............................12
            2.12.5. entityNotifications Group ........................12
      2.13. Multiple Agents ..........................................12
      2.14. Changes Since RFC 2037 ...................................12
            2.14.1. Textual Conventions ..............................12
            2.14.2. New entPhysicalTable Objects .....................13
            2.14.3. New entLogicalTable Objects ......................13
            2.14.4. Bug Fixes ........................................13
      2.15. Changes Since RFC 2737 ...................................13
            2.15.1. Textual Conventions ..............................13
            2.15.2. New Objects ......................................14
            2.15.3. Bug Fixes ........................................14
   3. Definitions ....................................................14
   4. Usage Examples .................................................44
      4.1. Router/Bridge .............................................44
      4.2. Repeaters .................................................50
   5. Security Considerations ........................................57
   6. IANA Considerations ............................................58
   7. Acknowledgements ...............................................59
   8. References .....................................................59
      8.1. Normative References ......................................59
      8.2. Informative References ....................................59

1.  The SNMP 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

   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
     that has a single agent;

   - multiple repeaters supported by a single agent;

   - multiple OSPF backbone areas, each 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 single agent present in each of these cases implies a
   relationship binds these entities.  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 which logical entities
   are managed by the agent (with some version of SNMP) in order 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 SNMP 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.

   Version 2 of this MIB addresses new requirements, which have emerged
   since the publication of the first Entity MIB (RFC 2037 [RFC2037]).
   There is a need for a standardized way of providing non-volatile,
   administratively-assigned identifiers for physical components
   represented with the Entity MIB.  There is also a need to align the
   Entity MIB with the SNMPv3 administrative framework (STD 62, RFC 3411
   [RFC3411]).  Implementation experience has shown that additional
   physical component attributes are also desirable.

   Version 3 of this MIB addresses new requirements, which have emerged
   since the publication of the second Entity MIB (RFC 2737 [RFC2737]).
   There is a need to identify physical entities that are central
   processing units (CPUs) and a need to provide a textual convention
   that identifies an entPhysicalIndex value or zero, where the value
   zero has application-specific semantics.  Two new objects have been
   added to the entPhysicalTable to identify the manufacturing date and
   provide additional URIs for a particular physical entity.

2.1.  Terms

   Some new terms are used throughout this document:

   - Naming Scope
     A "naming scope" represents the set of information that may be
     potentially accessed through a single SNMP 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.  For SNMPv3, the
     term 'context' is used instead of 'naming scope'.  The complete
     definition of an SNMP context can be found in section 3.3.1 of RFC
     3411 [RFC3411].

   - Multi-Scoped Object
     A MIB object, for which identical instance values identify
     different managed information in different naming scopes, is called
     a "multi-scoped" MIB object.

   - Single-Scoped Object
     A MIB object, for which identical instance values identify the same
     managed information in different naming scopes, is called a
     "single-scoped" MIB object.

   - 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.  Determining which physical components are represented by an
     agent in the EntPhysicalTable is an implementation-specific matter.
     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 be modeled as 'contained' within
     another physical component.  A "containment-tree" is the conceptual
     sequence of entPhysicalIndex values that 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.

2.2.  Relationship to Community Strings

   For community-based SNMP, differentiating logical entities is one
   (but not the only) purpose of the community string (RFC 1157
   [RFC1157]).  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.  This is
   possible, providing they have no need for the same instance of a MIB
   object to represent different managed information.

2.3.  Relationship to SNMP Contexts

   Version 2 of the Entity MIB contains support for associating SNMPv3
   contexts with logical entities.  Two new MIB objects, defining an
   SnmpEngineID and ContextName pair, are used together to identify an
   SNMP context associated with a logical entity.  This context can be
   used (in conjunction with the entLogicalTAddress and
   entLogicalTDomain MIB objects) to send SNMPv3 messages on behalf of a
   particular logical entity.

2.4.  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.  A Network Management
   System (NMS) cannot determine whether MIB instances in different
   naming scopes are realized locally or remotely (e.g., via some proxy
   mechanism) by examining any particular Entity MIB objects.

   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.

   Note that for community-based versions of SNMP, a network
   administrator will likely be able to associate community strings with
   naming scopes that have proprietary mechanisms, as a matter of
   configuration.  There are no mechanisms for managing naming scopes
   defined in this MIB.

2.5.  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.

2.6.  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 (RFC
   2863 [RFC2863]).  Because ifIndex values in different contexts are
   not related to one another, the interface to physical component
   associations are relative to the same logical entity within the
   agent.

   The Entity MIB also contains 'entPhysicalName' and 'entPhysicalAlias'
   objects, which approximate the semantics of the 'ifName' and
   'ifAlias' objects (respectively) from the Interfaces MIB [RFC2863],
   for all types of physical components.

2.7.  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, or each interface in the ifTable.

2.8.  Relationship to Naming Scopes

   There is some question as to which MIB objects may be returned within
   a given naming scope.  MIB objects which are not multi-scoped within
   a managed system are likely to ignore context information in
   implementation.  In such a case, it is likely such objects will be
   returned in all naming scopes (e.g., not just the 'default' naming
   scope or the SNMPv3 default context).

   For example, a community string used to access the management
   information for logical device 'bridge2' may allow access to all the
   non-bridge related objects in the 'default' naming scope, as well as
   a second instance of the Bridge MIB (RFC 1493 [RFC1493]).

   The isolation of single-scoped MIB objects by the agent is an
   implementation-specific matter.  An agent may wish to limit the
   objects returned in a particular naming scope to only the multi-
   scoped objects in that naming scope (e.g., system group and the
   Bridge MIB).  In this case, all single-scoped management information
   would belong to a common naming scope (e.g., 'default'), which itself
   may contain some multi-scoped objects (e.g., system group).

2.9.  Multiple Instances of the Entity MIB

   It is possible that more than one agent may exist in a managed
   system.  In such cases, multiple instances of the Entity MIB
   (representing the same managed objects) may be available to an NMS.

   In order to reduce complexity for agent implementation, multiple
   instances of the Entity MIB are not required to be equivalent or even
   consistent.  An NMS may be able to 'align' instances returned by
   different agents by examining the columns of each table, but vendor-
   specific identifiers and (especially) index values are likely to be
   different.  Each agent may be managing different subsets of the
   entire chassis as well.

   When all of a physically-modular device is represented by a single
   agent, the entry (for which entPhysicalContainedIn has the value
   zero) would likely have 'chassis' as the value of its
   entPhysicalClass.  Alternatively, for an agent on a module where the

   agent represents only the physical entities on that module (not those
   on other modules), the entry (for which entPhysicalContainedIn has
   the value zero) would likely have 'module' as the value of its
   entPhysicalClass.

   An agent implementation of the entLogicalTable is not required to
   contain information about logical entities managed primarily by other
   agents.  That is, the entLogicalTAddress and entLogicalTDomain
   objects in the entLogicalTable are provided to support an historical
   multiplexing mechanism, not to identify other SNMP agents.

   Note that the Entity MIB is a single-scoped MIB, in the event an
   agent represents the MIB in different naming scopes.

2.10.  Re-Configuration of Entities

   Most of the MIB objects defined in this MIB have, at most, a read-
   only MAX-ACCESS clause.  This is a conscious decision by the working
   group to limit this MIB's scope.  The second version of the Entity
   MIB allows a network administrator to configure some common
   attributes of physical components.

2.11.  Textual Convention Change

   Version 1 of the Entity MIB contains three MIB objects defined with
   the (now obsolete) DisplayString textual convention.  In version 2 of
   the Entity MIB, the syntax for these objects has been updated to use
   the (now preferred) SnmpAdminString textual convention.

   The working group realizes that this change is not strictly supported
   by SMIv2.  In our judgment, the alternative of deprecating the old
   objects and defining new objects would have a more adverse impact on
   backward compatibility and interoperability, given the particular
   semantics of these objects.

2.12.  MIB Structure

   The Entity MIB contains five groups of MIB objects:

   - entityPhysical group
     Describes the physical entities managed by a single agent.

   - entityLogical group
     Describes the logical entities managed by a single agent.

   - entityMapping group
     Describes the associations between the physical entities, logical
     entities, interfaces, and non-interface ports managed by a single
     agent.

   - entityGeneral group
     Describes general system attributes shared by potentially all types
     of entities managed by a single agent.

   - entityNotifications group
     Contains status indication notifications.

2.12.1.  entityPhysical Group

   This group contains a single table to identify physical system
   components, called the entPhysicalTable.

   The entPhysicalTable contains one row per physical entity, and must
   always contain at least one row for an "overall" physical entity,
   which should have an entPhysicalClass value of 'stack(11)',
   'chassis(3)' or 'module(9)'.

   Each 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.

   Version 2 of the Entity MIB provides additional MIB objects for each
   physical entity.  Some common read-only attributes have been added,
   as well as three writable string objects.

   - entPhysicalAlias
     This string can be used by an NMS as a non-volatile identifier for
     the physical component.  Maintaining a non-volatile string for
     every physical component represented in the entPhysicalTable can be
     costly and unnecessary.  An agent may algorithmically generate
     'entPhysicalAlias' strings for particular entries (e.g., based on
     the entPhysicalClass value).

   - entPhysicalAssetID
     This string is provided to store a user-specific asset identifier
     for removable physical components.  In order to reduce the non-
     volatile storage needed by a particular agent, a network
     administrator should only assign asset identifiers to physical
     entities that are field-replaceable (i.e., not permanently
     contained within another physical entity).

   - entPhysicalSerialNum
     This string is provided to store a vendor-specific serial number
     string for physical components.  This writable object is used when
     an agent cannot identify the serial numbers of all installed
     physical entities, and a network administrator wishes to configure
     the non-volatile serial number strings manually (via an NMS
     application).

   Version 3 of the Entity MIB provides two additional MIB objects for
   each physical entity:

   - entPhysicalMfgDate
     This object contains the date of manufacturing of the managed
     entity.  If the manufacturing date is unknown or not supported the
     object is not instantiated.  The special value '0000000000000000'H
     may also be returned in this case.

   - entPhysicalUris
     This object provides additional identification information about
     the physical entity.

     This object contains one or more Uniform Resource Identifiers
     (URIs) and, therefore, the syntax of this object must conform to
     RFC 3986 [RFC3986] section 2.  Uniform Resource Names (URNs), RFC
     3406 [RFC3406], are resource identifiers with the specific
     requirements for enabling location independent identification of a
     resource, as well as longevity of reference.  URNs are part of the
     larger URI family with the specific goal of providing persistent
     naming of resources.  URI schemes and URN name spaces are
     registered by IANA (see http://www.iana.org/assignments/uri-schemes
     and http://www.iana.org/assignments/urn-namespaces).

     For example, the entPhysicalUris object may be used to encode a URI
     containing a Common Language Equipment Identifier (CLEI) URN for
     the managed physical entity.  The URN name space for CLEIs is
     defined in [RFC4152], and the CLEI format is defined in
     [T1.213][T1.213a].  For example, an entPhysicalUris instance may
     have the value of

        URN:CLEI:D4CE18B7AA

     [RFC3986] and [RFC4152] identify this as a URI in the CLEI URN name
     space.  The specific CLEI code, D4CE18B7AA, is based on the example
     provided in [T1.213a].

     Multiple URIs may be present and are separated by white space
     characters.  Leading and trailing white space characters are
     ignored.

     If no additional identification information is known about the
     physical entity or supported, the object is not instantiated.

2.12.2.  entityLogical Group

   This group contains a single table to identify logical entities,
   called the entLogicalTable.

   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 access to the MIB information for the logical
   entity.  This includes SNMP versions that use a community name (with
   some form of implied context representation) and SNMP versions that
   use the SNMP ARCH [RFC3411] method of context identification.

   If an agent represents multiple logical entities with this MIB, then
   this group must be implemented for all logical entities known to the
   agent.

   If an agent represents a single logical entity, or multiple logical
   entities within a single naming scope, then implementation of this
   group may be omitted by the agent.

2.12.3.  entityMapping Group

   This group contains three tables to identify associations between
   different system components.

   - entLPMappingTable
     This table 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.  If an agent
     represents a single logical entity, or multiple logical entities
     within a single naming scope, then implementation of this table may
     be omitted by the agent.

   - entAliasMappingTable
     This table 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.  If an agent represents

     a single logical entity, or multiple logical entities within a
     single naming scope, then implementation of this table may be
     omitted by the agent.

   - entPhysicalContainsTable
     This table 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.

2.12.4.  entityGeneral Group

   This group contains general information relating to the other object
   groups.

   At this time, the entGeneral group contains a single scalar object
   (entLastChangeTime), which represents the value of sysUptime when any
   part of the Entity MIB configuration last changed.

2.12.5.  entityNotifications Group

   This group contains notification definitions relating to the overall
   status of the Entity MIB instantiation.

2.13.  Multiple Agents

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

   However, there is no agreement at this time as to the degree of
   cooperation that should be expected for agent implementations.
   Therefore, multiple agents within the same managed system are free to
   implement the Entity MIB independently.  (For more information, refer
   to Section 2.9, "Multiple Instances of the Entity MIB".)

2.14.  Changes Since RFC 2037

2.14.1.  Textual Conventions

   The PhysicalClass TC text has been clarified, and a new enumeration
   to support 'stackable' components has been added.  The
   SnmpEngineIdOrNone TC has been added to support SNMPv3.

2.14.2.  New entPhysicalTable Objects

   The entPhysicalHardwareRev, entPhysicalFirmwareRev, and
   entPhysicalSoftwareRev objects have been added for revision
   identification.

   The entPhysicalSerialNum, entPhysicalMfgName, entPhysicalModelName,
   and entPhysicalIsFru objects have been added for better vendor
   identification for physical components.  In the event the agent
   cannot identify this information, the entPhysicalSerialNum object can
   be set by a management station.

   The entPhysicalAlias and entPhysicalAssetID objects have been added
   for better user component identification.  These objects are intended
   to be set by a management station and preserved by the agent across
   restarts.

2.14.3.  New entLogicalTable Objects

   The entLogicalContextEngineID and entLogicalContextName objects have
   been added to provide an SNMP context for SNMPv3 access on behalf of
   a logical entity.

2.14.4.  Bug Fixes

   A bug was fixed in the entLogicalCommunity object.  The subrange was
   incorrect (1..255) and is now (0..255).  The description clause has
   also been clarified.  This object is now deprecated.

   The entLastChangeTime object description has been changed to
   generalize the events that cause an update to the last change
   timestamp.

   The syntax was changed from DisplayString to SnmpAdminString for the
   entPhysicalDescr, entPhysicalName, and entLogicalDescr objects.

2.15.  Changes Since RFC 2737

2.15.1.  Textual Conventions

   The PhysicalIndexOrZero TC has been added to allow objects to
   reference an entPhysicalIndex value or zero.  The PhysicalClass TC
   has been extended to support a new enumeration for central processing
   units.

2.15.2.  New Objects

   The entPhysicalMfgDate object has been added to the entPhysicalTable
   to provide the date of manufacturing of the managed entity.

   The entPhysicalUris object has been added to the entPhysicalTable to
   provide additional identification information about the physical
   entity, such as a Common Language Equipment Identifier (CLEI) URN.

2.15.3.  Bug Fixes

   The syntax was changed from INTEGER to Integer32 for the
   entPhysicalParentRelPos, entLogicalIndex, and
   entAliasLogicalIndexOrZero objects, and from INTEGER to
   PhysicalIndexOrZero for the entPhysicalContainedIn object.

3.  Definitions

ENTITY-MIB DEFINITIONS ::= BEGIN

IMPORTS
    MODULE-IDENTITY, OBJECT-TYPE, mib-2, NOTIFICATION-TYPE,
    Integer32
        FROM SNMPv2-SMI
    TDomain, TAddress, TEXTUAL-CONVENTION,
    AutonomousType, RowPointer, TimeStamp, TruthValue,
    DateAndTime
        FROM SNMPv2-TC
    MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
        FROM SNMPv2-CONF
    SnmpAdminString
        FROM SNMP-FRAMEWORK-MIB;

entityMIB MODULE-IDENTITY
    LAST-UPDATED "200508100000Z"
    ORGANIZATION "IETF ENTMIB Working Group"
    CONTACT-INFO
            "        WG E-mail: entmib@ietf.org
                     Mailing list subscription info:
                       http://www.ietf.org/mailman/listinfo/entmib

                     Andy Bierman
                     ietf@andybierman.com

                     Keith McCloghrie
                     Cisco Systems Inc.
                     170 West Tasman Drive
                     San Jose, CA 95134

                     +1 408-526-5260
                     kzm@cisco.com"

    DESCRIPTION
            "The MIB module for representing multiple logical
            entities supported by a single SNMP agent.

            Copyright (C) The Internet Society (2005).  This
            version of this MIB module is part of RFC 4133; see
            the RFC itself for full legal notices."

    REVISION        "200508100000Z"
    DESCRIPTION
            "Initial Version of Entity MIB (Version 3).
             This revision obsoletes RFC 2737.
             Additions:
               - cpu(12) enumeration added to PhysicalClass TC
               - DISPLAY-HINT clause to PhysicalIndex TC
               - PhysicalIndexOrZero TC
               - entPhysicalMfgDate object
               - entPhysicalUris object
             Changes:
               - entPhysicalContainedIn SYNTAX changed from
                 INTEGER to PhysicalIndexOrZero

             This version published as RFC 4133."

    REVISION        "199912070000Z"
    DESCRIPTION
            "Initial Version of Entity MIB (Version 2).
             This revision obsoletes RFC 2037.
             This version published as RFC 2737."

    REVISION        "199610310000Z"
    DESCRIPTION
            "Initial version (version 1), published as
             RFC 2037."
    ::= { mib-2 47 }

entityMIBObjects OBJECT IDENTIFIER ::= { entityMIB 1 }

-- MIB contains four groups
entityPhysical OBJECT IDENTIFIER ::= { entityMIBObjects 1 }
entityLogical  OBJECT IDENTIFIER ::= { entityMIBObjects 2 }
entityMapping  OBJECT IDENTIFIER ::= { entityMIBObjects 3 }
entityGeneral  OBJECT IDENTIFIER ::= { entityMIBObjects 4 }

-- Textual Conventions
PhysicalIndex ::= TEXTUAL-CONVENTION
    DISPLAY-HINT      "d"
    STATUS            current
    DESCRIPTION
            "An arbitrary value that uniquely identifies the physical
            entity.  The value should be a small, positive integer.
            Index values for different physical entities are not
            necessarily contiguous."
    SYNTAX Integer32 (1..2147483647)

PhysicalIndexOrZero ::= TEXTUAL-CONVENTION
    DISPLAY-HINT      "d"
    STATUS            current
    DESCRIPTION
            "This textual convention is an extension of the
            PhysicalIndex convention, which defines a greater than zero
            value used to identify a physical entity.  This extension
            permits the additional value of zero.  The semantics of the
            value zero are object-specific and must, therefore, be
            defined as part of the description of any object that uses
            this syntax.  Examples of the usage of this extension are
            situations where none or all physical entities need to be
            referenced."
    SYNTAX Integer32 (0..2147483647)

PhysicalClass ::= TEXTUAL-CONVENTION
    STATUS            current
    DESCRIPTION
            "An enumerated value which provides an indication of the
            general hardware type of a particular physical entity.
            There are no restrictions as to the number of
            entPhysicalEntries of each entPhysicalClass, which must be
            instantiated by an agent.

            The enumeration 'other' is applicable if the physical entity
            class is known, but does not match any of the supported
            values.

            The enumeration 'unknown' is applicable if the physical
            entity class is unknown to the agent.

            The enumeration 'chassis' is applicable if the physical
            entity class is an overall container for networking
            equipment.  Any class of physical entity, except a stack,
            may be contained within a chassis; and a chassis may only
            be contained within a stack.

            The enumeration 'backplane' is applicable if the physical
            entity class is some sort of device for aggregating and
            forwarding networking traffic, such as a shared backplane in
            a modular ethernet switch.  Note that an agent may model a
            backplane as a single physical entity, which is actually
            implemented as multiple discrete physical components (within
            a chassis or stack).

            The enumeration 'container' is applicable if the physical
            entity class is capable of containing one or more removable
            physical entities, possibly of different types.  For
            example, each (empty or full) slot in a chassis will be
            modeled as a container.  Note that all removable physical
            entities should be modeled within a container entity, such
            as field-replaceable modules, fans, or power supplies.  Note
            that all known containers should be modeled by the agent,
            including empty containers.

            The enumeration 'powerSupply' is applicable if the physical
            entity class is a power-supplying component.

            The enumeration 'fan' is applicable if the physical entity
            class is a fan or other heat-reduction component.

            The enumeration 'sensor' is applicable if the physical
            entity class is some sort of sensor, such as a temperature
            sensor within a router chassis.

            The enumeration 'module' is applicable if the physical
            entity class is some sort of self-contained sub-system.  If
            the enumeration 'module' is removable, then it should be
            modeled within a container entity, otherwise it should be
            modeled directly within another physical entity (e.g., a
            chassis or another module).

            The enumeration 'port' is applicable if the physical entity
            class is some sort of networking port, capable of receiving
            and/or transmitting networking traffic.

            The enumeration 'stack' is applicable if the physical entity
            class is some sort of super-container (possibly virtual),
            intended to group together multiple chassis entities.  A
            stack may be realized by a 'virtual' cable, a real
            interconnect cable, attached to multiple chassis, or may in
            fact be comprised of multiple interconnect cables.  A stack
            should not be modeled within any other physical entities,
            but a stack may be contained within another stack.  Only
            chassis entities should be contained within a stack.

            The enumeration 'cpu' is applicable if the physical entity
            class is some sort of central processing unit."
    SYNTAX      INTEGER  {
       other(1),
       unknown(2),
       chassis(3),
       backplane(4),
       container(5),     -- e.g., chassis slot or daughter-card holder
       powerSupply(6),
       fan(7),
       sensor(8),
       module(9),        -- e.g., plug-in card or daughter-card
       port(10),
       stack(11),        -- e.g., stack of multiple chassis entities
       cpu(12)
    }

SnmpEngineIdOrNone ::= TEXTUAL-CONVENTION
    STATUS            current
    DESCRIPTION
            "A specially formatted SnmpEngineID string for use with the
            Entity MIB.

            If an instance of an object of SYNTAX SnmpEngineIdOrNone has
            a non-zero length, then the object encoding and semantics
            are defined by the SnmpEngineID textual convention (see STD
            62, RFC 3411 [RFC3411]).

            If an instance of an object of SYNTAX SnmpEngineIdOrNone
            contains a zero-length string, then no appropriate
            SnmpEngineID is associated with the logical entity (i.e.,
            SNMPv3 is not supported)."
    SYNTAX OCTET STRING (SIZE(0..32)) -- empty string or SnmpEngineID

--           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."
    ::= { entityPhysical 1 }

entPhysicalEntry       OBJECT-TYPE
    SYNTAX      EntPhysicalEntry
    MAX-ACCESS  not-accessible

    STATUS      current
    DESCRIPTION
            "Information about a particular physical entity.

            Each entry provides objects (entPhysicalDescr,
            entPhysicalVendorType, and entPhysicalClass) to help an NMS
            identify and characterize the entry, and objects
            (entPhysicalContainedIn and entPhysicalParentRelPos) to help
            an NMS relate the particular entry to other entries in this
            table."
    INDEX   { entPhysicalIndex }
    ::= { entPhysicalTable 1 }

EntPhysicalEntry ::= SEQUENCE {
      entPhysicalIndex          PhysicalIndex,
      entPhysicalDescr          SnmpAdminString,
      entPhysicalVendorType     AutonomousType,
      entPhysicalContainedIn    PhysicalIndexOrZero,
      entPhysicalClass          PhysicalClass,
      entPhysicalParentRelPos   Integer32,
      entPhysicalName           SnmpAdminString,
      entPhysicalHardwareRev    SnmpAdminString,
      entPhysicalFirmwareRev    SnmpAdminString,
      entPhysicalSoftwareRev    SnmpAdminString,
      entPhysicalSerialNum      SnmpAdminString,
      entPhysicalMfgName        SnmpAdminString,
      entPhysicalModelName      SnmpAdminString,
      entPhysicalAlias          SnmpAdminString,
      entPhysicalAssetID        SnmpAdminString,
      entPhysicalIsFRU          TruthValue,
      entPhysicalMfgDate        DateAndTime,
      entPhysicalUris           OCTET STRING

}

entPhysicalIndex    OBJECT-TYPE
    SYNTAX      PhysicalIndex
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "The index for this entry."
    ::= { entPhysicalEntry 1 }

entPhysicalDescr OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION

            "A textual description of physical entity.  This object
            should contain a string that identifies the manufacturer's
            name for the physical entity, and should be set to a
            distinct value for each version or model of the 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 an enterprise-specific
            registration identifier value indicating the specific
            equipment type in detail.  The associated instance of
            entPhysicalClass is used to indicate the general type of
            hardware device.

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

entPhysicalContainedIn OBJECT-TYPE
    SYNTAX      PhysicalIndexOrZero
    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.

            In the event that a physical entity is contained by more
            than one physical entity (e.g., double-wide modules), this
            object should identify the containing entity with the lowest
            value of entPhysicalIndex."
    ::= { entPhysicalEntry 4 }

entPhysicalClass OBJECT-TYPE
    SYNTAX      PhysicalClass
    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 that most accurately indicates the general class of
            the physical entity, or the primary class if there is more
            than one entity.

            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      Integer32 (-1..2147483647)
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "An indication of the relative position of this 'child'
            component among all its 'sibling' components.  Sibling
            components are defined as entPhysicalEntries that share the
            same instance values of each of the entPhysicalContainedIn
            and entPhysicalClass objects.

            An NMS can use this object to identify the relative ordering
            for all sibling components of a particular parent
            (identified by the entPhysicalContainedIn instance in each
            sibling entry).

            If possible, this value should match any external labeling
            of the physical component.  For example, for a container
            (e.g., card slot) labeled as 'slot #3',
            entPhysicalParentRelPos should have the value '3'.  Note
            that the entPhysicalEntry for the module plugged in slot 3
            should have an entPhysicalParentRelPos value of '1'.

            If the physical position of this component does not match
            any external numbering or clearly visible ordering, then
            user documentation or other external reference material
            should be used to determine the parent-relative position.
            If this is not possible, then the agent should assign a
            consistent (but possibly 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 '-1' is
            returned.  Otherwise, a non-negative integer is returned,
            indicating the parent-relative position of this physical
            entity.

            Parent-relative ordering normally starts from '1' and
            continues to 'N', where 'N' represents the highest
            positioned child entity.  However, if the physical entities
            (e.g., slots) are labeled from a starting position of zero,
            then the first sibling should be associated with an
            entPhysicalParentRelPos value of '0'.  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 }

entPhysicalName OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The textual name of the physical entity.  The value of this
            object should be the name of the component as assigned by
            the local device and should be suitable for use in commands
            entered at the device's `console'.  This might be a text
            name (e.g., `console') or a simple component number (e.g.,
            port or module number, such as `1'), depending on the
            physical component naming syntax of the device.

            If there is no local name, or if this object is otherwise
            not applicable, then this object contains a zero-length
            string.

            Note that the value of entPhysicalName for two physical
            entities will be the same in the event that the console
            interface does not distinguish between them, e.g., slot-1
            and the card in slot-1."
    ::= { entPhysicalEntry 7 }

entPhysicalHardwareRev    OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The vendor-specific hardware revision string for the
            physical entity.  The preferred value is the hardware
            revision identifier actually printed on the component itself
            (if present).

            Note that if revision information is stored internally in a
            non-printable (e.g., binary) format, then the agent must
            convert such information to a printable format, in an
            implementation-specific manner.

            If no specific hardware revision string is associated with
            the physical component, or if this information is unknown to
            the agent, then this object will contain a zero-length
            string."
    ::= { entPhysicalEntry 8 }

entPhysicalFirmwareRev    OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The vendor-specific firmware revision string for the
            physical entity.

            Note that if revision information is stored internally in a
            non-printable (e.g., binary) format, then the agent must
            convert such information to a printable format, in an
            implementation-specific manner.

            If no specific firmware programs are associated with the
            physical component, or if this information is unknown to the
            agent, then this object will contain a zero-length string."
    ::= { entPhysicalEntry 9 }

entPhysicalSoftwareRev    OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The vendor-specific software revision string for the
            physical entity.

            Note that if revision information is stored internally in a

            non-printable (e.g., binary) format, then the agent must
            convert such information to a printable format, in an
            implementation-specific manner.

            If no specific software programs are associated with the
            physical component, or if this information is unknown to the
            agent, then this object will contain a zero-length string."
    ::= { entPhysicalEntry 10 }

entPhysicalSerialNum   OBJECT-TYPE
    SYNTAX      SnmpAdminString (SIZE (0..32))
    MAX-ACCESS  read-write
    STATUS      current
    DESCRIPTION
            "The vendor-specific serial number string for the physical
            entity.  The preferred value is the serial number string
            actually printed on the component itself (if present).

            On the first instantiation of an physical entity, the value
            of entPhysicalSerialNum associated with that entity is set
            to the correct vendor-assigned serial number, if this
            information is available to the agent.  If a serial number
            is unknown or non-existent, the entPhysicalSerialNum will be
            set to a zero-length string instead.

            Note that implementations that can correctly identify the
            serial numbers of all installed physical entities do not
            need to provide write access to the entPhysicalSerialNum
            object.  Agents which cannot provide non-volatile storage
            for the entPhysicalSerialNum strings are not required to
            implement write access for this object.

            Not every physical component will have a serial number, or
            even need one.  Physical entities for which the associated
            value of the entPhysicalIsFRU object is equal to 'false(2)'
            (e.g., the repeater ports within a repeater module), do not
            need their own unique serial number.  An agent does not have
            to provide write access for such entities, and may return a
            zero-length string.

            If write access is implemented for an instance of
            entPhysicalSerialNum, and a value is written into the
            instance, the agent must retain the supplied value in the
            entPhysicalSerialNum instance (associated with the same
            physical entity) for as long as that entity remains
            instantiated.  This includes instantiations across all
            re-initializations/reboots of the network management system,
            including those resulting in a change of the physical

            entity's entPhysicalIndex value."
    ::= { entPhysicalEntry 11 }

entPhysicalMfgName   OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The name of the manufacturer of this physical component.
            The preferred value is the manufacturer name string actually
            printed on the component itself (if present).

            Note that comparisons between instances of the
            entPhysicalModelName, entPhysicalFirmwareRev,
            entPhysicalSoftwareRev, and the entPhysicalSerialNum
            objects, are only meaningful amongst entPhysicalEntries with
            the same value of entPhysicalMfgName.

            If the manufacturer name string associated with the physical
            component is unknown to the agent, then this object will
            contain a zero-length string."
    ::= { entPhysicalEntry 12 }

entPhysicalModelName   OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The vendor-specific model name identifier string associated
            with this physical component.  The preferred value is the
            customer-visible part number, which may be printed on the
            component itself.

            If the model name string associated with the physical
            component is unknown to the agent, then this object will
            contain a zero-length string."
    ::= { entPhysicalEntry 13 }

entPhysicalAlias    OBJECT-TYPE
    SYNTAX      SnmpAdminString (SIZE (0..32))
    MAX-ACCESS  read-write
    STATUS      current
    DESCRIPTION
            "This object is an 'alias' name for the physical entity, as
            specified by a network manager, and provides a non-volatile
            'handle' for the physical entity.

            On the first instantiation of a physical entity, the value

            of entPhysicalAlias associated with that entity is set to
            the zero-length string.  However, the agent may set the
            value to a locally unique default value, instead of a
            zero-length string.

            If write access is implemented for an instance of
            entPhysicalAlias, and a value is written into the instance,
            the agent must retain the supplied value in the
            entPhysicalAlias instance (associated with the same physical
            entity) for as long as that entity remains instantiated.
            This includes instantiations across all
            re-initializations/reboots of the network management system,
            including those resulting in a change of the physical
            entity's entPhysicalIndex value."
    ::= { entPhysicalEntry 14 }

entPhysicalAssetID OBJECT-TYPE
    SYNTAX      SnmpAdminString (SIZE (0..32))
    MAX-ACCESS  read-write
    STATUS      current
    DESCRIPTION
            "This object is a user-assigned asset tracking identifier
            (as specified by a network manager) for the physical entity,
            and provides non-volatile storage of this information.

            On the first instantiation of a physical entity, the value
            of entPhysicalAssetID associated with that entity is set to
            the zero-length string.

            Not every physical component will have an asset tracking
            identifier, or even need one.  Physical entities for which
            the associated value of the entPhysicalIsFRU object is equal
            to 'false(2)' (e.g., the repeater ports within a repeater
            module), do not need their own unique asset tracking
            identifier.  An agent does not have to provide write access
            for such entities, and may instead return a zero-length
            string.

            If write access is implemented for an instance of
            entPhysicalAssetID, and a value is written into the
            instance, the agent must retain the supplied value in the
            entPhysicalAssetID instance (associated with the same
            physical entity) for as long as that entity remains
            instantiated.  This includes instantiations across all
            re-initializations/reboots of the network management system,
            including those resulting in a change of the physical
            entity's entPhysicalIndex value.

            If no asset tracking information is associated with the
            physical component, then this object will contain a
            zero-length string."
    ::= { entPhysicalEntry 15 }

entPhysicalIsFRU OBJECT-TYPE
    SYNTAX      TruthValue
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "This object indicates whether or not this physical entity
            is considered a 'field replaceable unit' by the vendor.  If
            this object contains the value 'true(1)' then this
            entPhysicalEntry identifies a field replaceable unit.  For
            all entPhysicalEntries that represent components
            permanently contained within a field replaceable unit, the
            value 'false(2)' should be returned for this object."
    ::= { entPhysicalEntry 16 }

entPhysicalMfgDate  OBJECT-TYPE
    SYNTAX      DateAndTime
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "This object contains the date of manufacturing of the
            managed entity.  If the manufacturing date is unknown or not
            supported, the object is not instantiated.  The special
            value '0000000000000000'H may also be returned in this
            case."
    ::= { entPhysicalEntry 17 }

entPhysicalUris OBJECT-TYPE
    SYNTAX      OCTET STRING
    MAX-ACCESS  read-write
    STATUS      current
    DESCRIPTION
            "This object contains additional identification information
            about the physical entity.  The object contains URIs and,
            therefore, the syntax of this object must conform to RFC
            3986, section 2.

            Multiple URIs may be present and are separated by white
            space characters.  Leading and trailing white space
            characters are ignored.

            If no additional identification information is known
            about the physical entity or supported, the object is not
            instantiated.  A zero length octet string may also be

            returned in this case."
    REFERENCE
            "RFC 3986, Uniform Resource Identifiers (URI): Generic
            Syntax, section 2, August 1998."

    ::= { entPhysicalEntry 18 }

--           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.  For agents
            that implement more than one naming scope, at least one
            entry must exist.  Agents which instantiate all MIB objects
            within a single naming scope are not required to implement
            this table."
    ::= { entityLogical 1 }

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            Integer32,
      entLogicalDescr            SnmpAdminString,
      entLogicalType             AutonomousType,
      entLogicalCommunity        OCTET STRING,
      entLogicalTAddress         TAddress,
      entLogicalTDomain          TDomain,
      entLogicalContextEngineID  SnmpEngineIdOrNone,
      entLogicalContextName      SnmpAdminString
}

entLogicalIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION

            "The value of this object uniquely identifies the logical
            entity.  The value should be a small positive integer; index
            values for different logical entities are not necessarily
            contiguous."
    ::= { entLogicalEntry 1 }

entLogicalDescr OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "A textual description of the logical entity.  This object
            should contain a string that identifies the manufacturer's
            name for the logical entity, and should be set to a distinct
            value for each version of the 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
            If an appropriate node in the SMI's naming hierarchy cannot
            be identified, the value 'mib-2' should be used."
    ::= { entLogicalEntry 3 }

entLogicalCommunity OBJECT-TYPE
    SYNTAX      OCTET STRING (SIZE (0..255))
    MAX-ACCESS  read-only
    STATUS      deprecated
    DESCRIPTION
            "An SNMPv1 or SNMPv2C 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 return a community string based on the
            privileges of the request used to read this object.  Note
            that an agent may return a community string with read-only
            privileges, even if this object is accessed with a
            read-write community string.  However, the agent must take

            care not to return a community string that allows more
            privileges than the community string used to access this
            object.

            A compliant SNMP agent may wish to conserve naming scopes by
            representing multiple logical entities in a single 'default'
            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 at
            least one additional community string is needed to represent
            'bridge2' and 'repeater2'.

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

            For agents not accessible via SNMPv1 or SNMPv2C, the value
            of this object is the empty string.  This object may also
            contain an empty string if a community string has not yet
            been assigned by the agent, or if no community string with
            suitable access rights can be returned for a particular SNMP
            request.

            Note that this object is deprecated.  Agents which implement
            SNMPv3 access should use the entLogicalContextEngineID and
            entLogicalContextName objects to identify the context
            associated with each logical entity.  SNMPv3 agents may
            return a zero-length string for this object, or may continue
            to return a community string (e.g., tri-lingual agent
            support)."
    ::= { 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, a TAddress is 6 octets long: the initial
            4 octets contain the IP-address in network-byte order and
            the last 2 contain the UDP port in network-byte order.
            Consult 'Transport Mappings for the Simple Network
            Management Protocol' (STD 62, RFC 3417 [RFC3417]) for
            further information on snmpUDPDomain."

    ::= { entLogicalEntry 5 }

entLogicalTDomain OBJECT-TYPE
    SYNTAX      TDomain
    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 Simple Network Management Protocol'
            (STD 62, RFC 3417 [RFC3417])."
    ::= { entLogicalEntry 6 }

entLogicalContextEngineID    OBJECT-TYPE
    SYNTAX      SnmpEngineIdOrNone
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The authoritative contextEngineID that can be used to send
            an SNMP message concerning information held by this logical
            entity, to the address specified by the associated
            'entLogicalTAddress/entLogicalTDomain' pair.

            This object, together with the associated
            entLogicalContextName object, defines the context associated
            with a particular logical entity, and allows access to SNMP
            engines identified by a contextEngineId and contextName
            pair.

            If no value has been configured by the agent, a zero-length
            string is returned, or the agent may choose not to
            instantiate this object at all."
    ::= { entLogicalEntry 7 }

entLogicalContextName    OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The contextName that can be used to send an SNMP message
            concerning information held by this logical entity, to the
            address specified by the associated
            'entLogicalTAddress/entLogicalTDomain' pair.

            This object, together with the associated
            entLogicalContextEngineID object, defines the context
            associated with a particular logical entity, and allows

            access to SNMP engines identified by a contextEngineId and
            contextName pair.

            If no value has been configured by the agent, a zero-length
            string is returned, or the agent may choose not to
            instantiate this object at all."
    ::= { entLogicalEntry 8 }

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.  For each logical entity
            known by this agent, there are zero or more mappings to the
            physical resources, which are used to realize that logical
            entity.

            An agent should limit the number and nature of entries in
            this table such that only meaningful and non-redundant
            information is returned.  For example, in a system that
            contains a single power supply, mappings between logical
            entities and the power supply are not useful and should not
            be included.

            Also, only the most appropriate physical component, which is
            closest to the root of a particular containment tree, should
            be identified in an entLPMapping entry.

            For example, suppose a bridge is realized on a particular
            module, and all ports on that module are ports on this
            bridge.  A mapping between the bridge and the module would
            be useful, but additional mappings between the bridge and
            each of the ports on that module would be redundant (because
            the entPhysicalContainedIn hierarchy can provide the same
            information).  On the other hand, if more than one bridge
            were utilizing ports on this module, then mappings between
            each bridge and the ports it used would be appropriate.

            Also, in the case of a single backplane repeater, a mapping
            for the backplane to the single repeater entity is not
            necessary."
    ::= { entityMapping 1 }

entLPMappingEntry       OBJECT-TYPE
    SYNTAX      EntLPMappingEntry
    MAX-ACCESS  not-accessible

    STATUS      current
    DESCRIPTION
            "Information about a particular logical entity to physical
            equipment association.  Note that the nature of the
            association is not specifically identified in this entry.
            It is expected that sufficient information exists in the
            MIBs used to manage a particular logical entity to infer how
            physical component information is utilized."
    INDEX       { entLogicalIndex, entLPPhysicalIndex }
    ::= { entLPMappingTable 1 }

EntLPMappingEntry ::= SEQUENCE {
      entLPPhysicalIndex         PhysicalIndex
}

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

-- 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, representing
            mappings of logical entity and physical component to
            external MIB identifiers.  Each physical port in the system
            may be associated with a mapping to an external identifier,
            which itself is associated with a particular logical
            entity's naming scope.  A 'wildcard' mechanism is provided
            to indicate that an identifier is associated with more than
            one logical entity."
    ::= { entityMapping 2 }

entAliasMappingEntry       OBJECT-TYPE
    SYNTAX      EntAliasMappingEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "Information about a particular physical equipment, logical

            entity to external identifier binding.  Each logical
            entity/physical component pair may be associated with one
            alias mapping.  The logical entity index may also be used as
            a 'wildcard' (refer to the entAliasLogicalIndexOrZero object
            DESCRIPTION clause for details.)

            Note that only entPhysicalIndex values that represent
            physical ports (i.e., associated entPhysicalClass value is
            'port(10)') are permitted to exist in this table."
    INDEX { entPhysicalIndex, entAliasLogicalIndexOrZero }
    ::= { entAliasMappingTable 1 }

EntAliasMappingEntry ::= SEQUENCE {
      entAliasLogicalIndexOrZero        Integer32,
      entAliasMappingIdentifier         RowPointer
}

entAliasLogicalIndexOrZero OBJECT-TYPE
    SYNTAX      Integer32 (0..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "The value of this object identifies the logical entity
            that defines the naming scope for the associated instance
            of the 'entAliasMappingIdentifier' object.

            If this object has a non-zero value, then it identifies the
            logical entity named by the same value of entLogicalIndex.

            If this object has a value of zero, then the mapping between
            the physical component and the alias identifier for this
            entAliasMapping entry is associated with all unspecified
            logical entities.  That is, a value of zero (the default
            mapping) identifies any logical entity that does not have
            an explicit entry in this table for a particular
            entPhysicalIndex/entAliasMappingIdentifier pair.

            For example, to indicate that a particular interface (e.g.,
            physical component 33) is identified by the same value of
            ifIndex for all logical entities, the following instance
            might exist:

                    entAliasMappingIdentifier.33.0 = ifIndex.5

            In the event an entPhysicalEntry is associated differently
            for some logical entities, additional entAliasMapping
            entries may exist, e.g.:

                    entAliasMappingIdentifier.33.0 = ifIndex.6
                    entAliasMappingIdentifier.33.4 =  ifIndex.1
                    entAliasMappingIdentifier.33.5 =  ifIndex.1
                    entAliasMappingIdentifier.33.10 = ifIndex.12

            Note that entries with non-zero entAliasLogicalIndexOrZero
            index values have precedence over zero-indexed entries.  In
            this example, all logical entities except 4, 5, and 10,
            associate physical entity 33 with ifIndex.6."
    ::= { entAliasMappingEntry 1 }

entAliasMappingIdentifier OBJECT-TYPE
    SYNTAX      RowPointer
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The value of this object identifies a particular conceptual
            row associated with the indicated entPhysicalIndex and
            entLogicalIndex pair.

            Because only physical ports are modeled in this table, only
            entries that represent interfaces or ports are allowed.  If
            an ifEntry exists on behalf of a particular physical port,
            then this object should identify the associated 'ifEntry'.
            For repeater ports, the appropriate row in the
            'rptrPortGroupTable' should be identified instead.

            For example, suppose a physical port was represented by
            entPhysicalEntry.3, entLogicalEntry.15 existed for a
            repeater, and entLogicalEntry.22 existed for a bridge.  Then
            there might be two related instances of
            entAliasMappingIdentifier:
               entAliasMappingIdentifier.3.15 == rptrPortGroupIndex.5.2
               entAliasMappingIdentifier.3.22 == ifIndex.17
            It is possible that other mappings (besides interfaces and
            repeater ports) may be defined in the future, as required.

            Bridge ports are identified by examining the Bridge MIB and
            appropriate ifEntries associated with each 'dot1dBasePort',
            and are thus not represented in this table."
    ::= { entAliasMappingEntry 2 }

-- physical mapping table
entPhysicalContainsTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF EntPhysicalContainsEntry
    MAX-ACCESS  not-accessible
    STATUS      current

    DESCRIPTION
            "A table that exposes the container/'containee'
            relationships between physical entities.  This table
            provides all the information found by constructing the
            virtual containment tree for a given entPhysicalTable, but
            in a more direct format.

            In the event a physical entity is contained by more than one
            other physical entity (e.g., double-wide modules), this
            table should include these additional mappings, which cannot
            be represented in the entPhysicalTable virtual containment
            tree."
    ::= { entityMapping 3 }

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     PhysicalIndex
}

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

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

                    - entPhysicalContainsTable
            "
    ::= { entityGeneral 1 }

-- Entity MIB Trap Definitions
entityMIBTraps      OBJECT IDENTIFIER ::= { entityMIB 2 }
entityMIBTrapPrefix OBJECT IDENTIFIER ::= { entityMIBTraps 0 }

entConfigChange NOTIFICATION-TYPE
    STATUS             current
    DESCRIPTION
            "An entConfigChange notification is generated when the value
            of entLastChangeTime changes.  It can be utilized by an NMS
            to trigger logical/physical entity table maintenance polls.

            An agent should not generate more than one entConfigChange
            'notification-event' in a given time interval (five seconds
            is the suggested default).  A 'notification-event' is the
            transmission of a single trap or inform PDU to a list of
            notification destinations.

            If additional configuration changes occur within the
            throttling period, then notification-events for these
            changes should be suppressed by the agent until the current
            throttling period expires.  At the end of a throttling
            period, one notification-event should be generated if any
            configuration changes occurred since the start of the
            throttling period.  In such a case, another throttling
            period is started right away.

            An NMS should periodically check the value of
            entLastChangeTime to detect any missed entConfigChange
            notification-events, e.g., due to throttling or transmission
            loss."
   ::= { entityMIBTrapPrefix 1 }

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

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

-- compliance statements
entityCompliance MODULE-COMPLIANCE
    STATUS  deprecated

    DESCRIPTION
            "The compliance statement for SNMP entities that implement
            version 1 of the Entity MIB."
    MODULE  -- this module
        MANDATORY-GROUPS {
                           entityPhysicalGroup,
                           entityLogicalGroup,
                           entityMappingGroup,
                           entityGeneralGroup,
                           entityNotificationsGroup
        }
    ::= { entityCompliances 1 }

entity2Compliance MODULE-COMPLIANCE
    STATUS  deprecated
    DESCRIPTION
            "The compliance statement for SNMP entities that implement
            version 2 of the Entity MIB."
    MODULE  -- this module
        MANDATORY-GROUPS {
                           entityPhysicalGroup,
                           entityPhysical2Group,
                           entityGeneralGroup,
                           entityNotificationsGroup
        }
        GROUP entityLogical2Group
        DESCRIPTION
            "Implementation of this group is not mandatory for agents
            that model all MIB object instances within a single naming
            scope."

        GROUP entityMappingGroup
        DESCRIPTION
            "Implementation of the entPhysicalContainsTable is mandatory
            for all agents.  Implementation of the entLPMappingTable and
            entAliasMappingTables are not mandatory for agents that
            model all MIB object instances within a single naming scope.

            Note that the entAliasMappingTable may be useful for all
            agents; however, implementation of the entityLogicalGroup or
            entityLogical2Group is required to support this table."

        OBJECT entPhysicalSerialNum
        MIN-ACCESS   not-accessible
        DESCRIPTION
            "Read and write access is not required for agents that
            cannot identify serial number information for physical
            entities, and/or cannot provide non-volatile storage for

            NMS-assigned serial numbers.

            Write access is not required for agents that can identify
            serial number information for physical entities, but cannot
            provide non-volatile storage for NMS-assigned serial
            numbers.

            Write access is not required for physical entities for which
            the associated value of the entPhysicalIsFRU object is equal
            to 'false(2)'."

        OBJECT entPhysicalAlias
        MIN-ACCESS   read-only
        DESCRIPTION
            "Write access is required only if the associated
            entPhysicalClass value is equal to 'chassis(3)'."

        OBJECT entPhysicalAssetID
        MIN-ACCESS   not-accessible
        DESCRIPTION
            "Read and write access is not required for agents that
            cannot provide non-volatile storage for NMS-assigned asset
            identifiers.

            Write access is not required for physical entities for which
            the associated value of the entPhysicalIsFRU object is equal
            to 'false(2)'."

        OBJECT entPhysicalClass
        SYNTAX INTEGER {
            other(1),
            unknown(2),
            chassis(3),
            backplane(4),
            container(5),
            powerSupply(6),
            fan(7),
            sensor(8),
            module(9),
            port(10),
            stack(11)
        }
        DESCRIPTION
            "Implementation of the 'cpu(12)' enumeration is not
            required."

    ::= { entityCompliances 2 }

entity3Compliance MODULE-COMPLIANCE
    STATUS  current
    DESCRIPTION
            "The compliance statement for SNMP entities that implement
            version 3 of the Entity MIB."
    MODULE  -- this module
        MANDATORY-GROUPS {
                           entityPhysicalGroup,
                           entityPhysical2Group,
                           entityPhysical3Group,
                           entityGeneralGroup,
                           entityNotificationsGroup
        }
        GROUP entityLogical2Group
        DESCRIPTION
            "Implementation of this group is not mandatory for agents
            that model all MIB object instances within a single naming
            scope."

        GROUP entityMappingGroup
        DESCRIPTION
            "Implementation of the entPhysicalContainsTable is mandatory
            for all agents.  Implementation of the entLPMappingTable and
            entAliasMappingTables are not mandatory for agents that
            model all MIB object instances within a single naming scope.

            Note that the entAliasMappingTable may be useful for all
            agents; however, implementation of the entityLogicalGroup or
            entityLogical2Group is required to support this table."

        OBJECT entPhysicalSerialNum
        MIN-ACCESS   not-accessible
        DESCRIPTION
            "Read and write access is not required for agents that
            cannot identify serial number information for physical
            entities, and/or cannot provide non-volatile storage for
            NMS-assigned serial numbers.

            Write access is not required for agents that can identify
            serial number information for physical entities, but cannot
            provide non-volatile storage for NMS-assigned serial
            numbers.

            Write access is not required for physical entities for
            which the associated value of the entPhysicalIsFRU object
            is equal to 'false(2)'."

        OBJECT entPhysicalAlias

        MIN-ACCESS   read-only
        DESCRIPTION
            "Write access is required only if the associated
            entPhysicalClass value is equal to 'chassis(3)'."

        OBJECT entPhysicalAssetID
        MIN-ACCESS   not-accessible
        DESCRIPTION
            "Read and write access is not required for agents that
            cannot provide non-volatile storage for NMS-assigned asset
            identifiers.

            Write access is not required for physical entities for which
            the associated value of entPhysicalIsFRU is equal to
            'false(2)'."
    ::= { entityCompliances 3 }

-- MIB groupings
entityPhysicalGroup    OBJECT-GROUP
    OBJECTS {
              entPhysicalDescr,
              entPhysicalVendorType,
              entPhysicalContainedIn,
              entPhysicalClass,
              entPhysicalParentRelPos,
              entPhysicalName
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects used to represent physical
            system components, for which a single agent provides
            management information."
    ::= { entityGroups 1 }

entityLogicalGroup    OBJECT-GROUP
    OBJECTS {
              entLogicalDescr,
              entLogicalType,
              entLogicalCommunity,
              entLogicalTAddress,
              entLogicalTDomain
            }
    STATUS  deprecated
    DESCRIPTION
            "The collection of objects used to represent the list of
            logical entities, for which a single agent provides
            management information."

    ::= { entityGroups 2 }

entityMappingGroup    OBJECT-GROUP
    OBJECTS {
              entLPPhysicalIndex,
              entAliasMappingIdentifier,
              entPhysicalChildIndex
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects used to represent the
            associations between multiple logical entities, physical
            components, interfaces, and port identifiers, for which a
            single agent provides management information."
    ::= { entityGroups 3 }

entityGeneralGroup    OBJECT-GROUP
    OBJECTS {
              entLastChangeTime
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects used to represent general entity
            information, for which a single agent provides management
            information."
    ::= { entityGroups 4 }

entityNotificationsGroup NOTIFICATION-GROUP
    NOTIFICATIONS { entConfigChange }
    STATUS        current
    DESCRIPTION
            "The collection of notifications used to indicate Entity MIB
            data consistency and general status information."
    ::= { entityGroups 5 }

entityPhysical2Group    OBJECT-GROUP
    OBJECTS {
              entPhysicalHardwareRev,
              entPhysicalFirmwareRev,
              entPhysicalSoftwareRev,
              entPhysicalSerialNum,
              entPhysicalMfgName,
              entPhysicalModelName,
              entPhysicalAlias,
              entPhysicalAssetID,
              entPhysicalIsFRU
            }
    STATUS  current

    DESCRIPTION
            "The collection of objects used to represent physical
            system components, for which a single agent provides
            management information.  This group augments the objects
            contained in the entityPhysicalGroup."
    ::= { entityGroups 6 }

entityLogical2Group    OBJECT-GROUP
    OBJECTS {
              entLogicalDescr,
              entLogicalType,
              entLogicalTAddress,
              entLogicalTDomain,
              entLogicalContextEngineID,
              entLogicalContextName
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects used to represent the
            list of logical entities, for which a single SNMP entity
            provides management information."
    ::= { entityGroups 7 }

entityPhysical3Group    OBJECT-GROUP
    OBJECTS {
              entPhysicalMfgDate,
              entPhysicalUris
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects used to represent physical
            system components, for which a single agent provides
            management information.  This group augments the objects
            contained in the entityPhysicalGroup."
    ::= { entityGroups 8 }

END

4.  Usage Examples

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

4.1.  Router/Bridge

   The first example is a 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
         entPhysicalName.1 ==              '100-A'
         entPhysicalHardwareRev.1 ==       'A(1.00.02)'
         entPhysicalSoftwareRev.1 ==       ''
         entPhysicalFirmwareRev.1 ==       ''
         entPhysicalSerialNum.1 ==         'C100076544'
         entPhysicalMfgName.1 ==           'Acme'
         entPhysicalModelName.1 ==         '100'
         entPhysicalAlias.1 ==             'cl-SJ17-3-006:rack1:rtr-U3'
         entPhysicalAssetID.1 ==           '0007372293'
         entPhysicalIsFRU.1 ==             true(1)
         entPhysicalMfgDate.1 ==           '2002-5-26,13:30:30.0,-4:0'
         entPhysicalUris.1 ==              'URN:CLEI:CNME120ARA'
       2 slots within the chassis:
         entPhysicalDescr.2 ==             'Acme Chassis Slot Type AA'
         entPhysicalVendorType.2  ==       acmeProducts.slotTypes.1
         entPhysicalContainedIn.2 ==       1
         entPhysicalClass.2 ==             container(5)
         entPhysicalParentRelPos.2 ==      1
         entPhysicalName.2 ==              'S1'
         entPhysicalHardwareRev.2 ==       'B(1.00.01)'
         entPhysicalSoftwareRev.2 ==       ''
         entPhysicalFirmwareRev.2 ==       ''
         entPhysicalSerialNum.2 ==         ''
         entPhysicalMfgName.2 ==           'Acme'
         entPhysicalModelName.2 ==         'AA'
         entPhysicalAlias.2 ==             ''

         entPhysicalAssetID.2 ==           ''
         entPhysicalIsFRU.2 ==             false(2)
         entPhysicalMfgDate.2 ==           '2002-7-26,12:22:12.0,-4:0'
         entPhysicalUris.2 ==              'URN:CLEI:CNME123ARA'

         entPhysicalDescr.3 ==             'Acme Chassis Slot Type AA'
         entPhysicalVendorType.3 =         acmeProducts.slotTypes.1
         entPhysicalContainedIn.3 ==       1
         entPhysicalClass.3 ==             container(5)
         entPhysicalParentRelPos.3 ==      2
         entPhysicalName.3 ==              'S2'
         entPhysicalHardwareRev.3 ==       '1.00.07'
         entPhysicalSoftwareRev.3 ==       ''
         entPhysicalFirmwareRev.3 ==       ''
         entPhysicalSerialNum.3 ==         ''
         entPhysicalMfgName.3 ==           'Acme'
         entPhysicalModelName.3 ==         'AA'
         entPhysicalAlias.3 ==             ''
         entPhysicalAssetID.3 ==           ''
         entPhysicalIsFRU.3 ==             false(2)
         entPhysicalMfgDate.3 ==           '2002-7-26,12:12:12.0,-4:0'
         entPhysicalUris.3 ==              'URN:CLEI:CNME123ARA'

       2 Field-replaceable modules:
       Slot 1 contains a module with 3 ports:
         entPhysicalDescr.4 ==             'Acme Router-100'
         entPhysicalVendorType.4  ==       acmeProducts.moduleTypes.14
         entPhysicalContainedIn.4 ==       2
         entPhysicalClass.4 ==             module(9)
         entPhysicalParentRelPos.4 ==      1
         entPhysicalName.4 ==              'M1'
         entPhysicalHardwareRev.4 ==       '1.00.07'
         entPhysicalSoftwareRev.4 ==       '1.4.1'
         entPhysicalFirmwareRev.4 ==       'A(1.1)'
         entPhysicalSerialNum.4 ==         'C100087363'
         entPhysicalMfgName.4 ==           'Acme'
         entPhysicalModelName.4 ==         'R100-FE'
         entPhysicalAlias.4 ==             'rtr-U3:m1:SJ17-3-eng'
         entPhysicalAssetID.4 ==           '0007372462'
         entPhysicalIsFRU.4 ==             true(1)
         entPhysicalMfgDate.4 ==           '2003-7-18,13:30:30.0,-4:0'
         entPhysicalUris.4 ==              'URN:CLEI:CNRU123CAA'

         entPhysicalDescr.5 ==             'Acme Ethernet-100 Port'
         entPhysicalVendorType.5  ==       acmeProducts.portTypes.2
         entPhysicalContainedIn.5 ==       4
         entPhysicalClass.5 ==             port(10)
         entPhysicalParentRelPos.5 ==      1

         entPhysicalName.5 ==              'P1'
         entPhysicalHardwareRev.5 ==       'G(1.02)'
         entPhysicalSoftwareRev.5 ==       ''
         entPhysicalFirmwareRev.5 ==       '1.1'
         entPhysicalSerialNum.5 ==         ''
         entPhysicalMfgName.5 ==           'Acme'
         entPhysicalModelName.5 ==         'FE-100'
         entPhysicalAlias.5 ==             ''
         entPhysicalAssetID.5 ==           ''
         entPhysicalIsFRU.5 ==             false(2)
         entPhysicalMfgDate.5 ==           '2003-7-18,14:20:22.0,-4:0'
         entPhysicalUris.5 ==              'URN:CLEI:CNMES23ARA'

         entPhysicalDescr.6 ==             'Acme Ethernet-100 Port'
         entPhysicalVendorType.6  ==       acmeProducts.portTypes.2
         entPhysicalContainedIn.6 ==       4
         entPhysicalClass.6 ==             port(10)
         entPhysicalParentRelPos.6 ==      2
         entPhysicalName.6 ==              'P2'
         entPhysicalHardwareRev.6 ==       'G(1.02)'
         entPhysicalSoftwareRev.6 ==       ''
         entPhysicalFirmwareRev.6 ==       '1.1'
         entPhysicalSerialNum.6 ==         ''
         entPhysicalMfgName.6 ==           'Acme'
         entPhysicalModelName.6 ==         'FE-100'
         entPhysicalAlias.6 ==             ''
         entPhysicalAssetID.6 ==           ''
         entPhysicalIsFRU.6 ==             false(2)
         entPhysicalMfgDate.6 ==           '2003-7-19,10:15:15.0,-4:0'
         entPhysicalUris.6 ==              'URN:CLEI:CNMES23ARA'

         entPhysicalDescr.7 ==             'Acme Router-100 FDDI-Port'
         entPhysicalVendorType.7  ==       acmeProducts.portTypes.3
         entPhysicalContainedIn.7 ==       4
         entPhysicalClass.7 ==             port(10)
         entPhysicalParentRelPos.7 ==      3
         entPhysicalName.7 ==              'P3'
         entPhysicalHardwareRev.7 ==       'B(1.03)'
         entPhysicalSoftwareRev.7 ==       '2.5.1'
         entPhysicalFirmwareRev.7 ==       '2.5F'
         entPhysicalSerialNum.7 ==         ''
         entPhysicalMfgName.7 ==           'Acme'
         entPhysicalModelName.7 ==         'FDDI-100'
         entPhysicalAlias.7 ==             ''
         entPhysicalAssetID.7 ==           ''
         entPhysicalIsFRU.7 ==             false(2)

      Slot 2 contains another 3-port module:
         entPhysicalDescr.8 ==             'Acme Router-100 Comm Module'
         entPhysicalVendorType.8  ==       acmeProducts.moduleTypes.15
         entPhysicalContainedIn.8 ==       3
         entPhysicalClass.8 ==             module(9)
         entPhysicalParentRelPos.8 ==      1
         entPhysicalName.8 ==              'M2'
         entPhysicalHardwareRev.8 ==       '2.01.00'
         entPhysicalSoftwareRev.8 ==       '3.0.7'
         entPhysicalFirmwareRev.8 ==       'A(1.2)'
         entPhysicalSerialNum.8 ==         'C100098732'
         entPhysicalMfgName.8 ==           'Acme'
         entPhysicalModelName.8 ==         'C100'
         entPhysicalAlias.8 ==             'rtr-U3:m2:SJ17-2-eng'
         entPhysicalAssetID.8 ==           '0007373982'
         entPhysicalIsFRU.8 ==             true(1)
         entPhysicalMfgDate.8 ==           '2002-5-26,13:30:15.0,-4:0'
         entPhysicalUris.8 ==              'URN:CLEI:CNRT321MAA'

         entPhysicalDescr.9 ==             'Acme Fddi-100 Port'
         entPhysicalVendorType.9 ==        acmeProducts.portTypes.5
         entPhysicalContainedIn.9 ==       8
         entPhysicalClass.9 ==             port(10)
         entPhysicalParentRelPos.9 ==      1
         entPhysicalName.9 ==              'FDDI Primary'
         entPhysicalHardwareRev.9 ==       'CC(1.07)'
         entPhysicalSoftwareRev.9 ==       '2.0.34'
         entPhysicalFirmwareRev.9 ==       '1.1'
         entPhysicalSerialNum.9 ==         ''
         entPhysicalMfgName.9 ==           'Acme'
         entPhysicalModelName.9 ==         'FDDI-100'
         entPhysicalAlias.9 ==             ''
         entPhysicalAssetID.9 ==           ''
         entPhysicalIsFRU.9 ==             false(2)

         entPhysicalDescr.10 ==            'Acme Ethernet-100 Port'
         entPhysicalVendorType.10 ==       acmeProducts.portTypes.2
         entPhysicalContainedIn.10 ==      8
         entPhysicalClass.10 ==            port(10)
         entPhysicalParentRelPos.10 ==     2
         entPhysicalName.10 ==             'Ethernet A'
         entPhysicalHardwareRev.10 ==      'G(1.04)'
         entPhysicalSoftwareRev.10 ==      ''
         entPhysicalFirmwareRev.10 ==      '1.3'
         entPhysicalSerialNum.10 ==        ''
         entPhysicalMfgName.10 ==          'Acme'
         entPhysicalModelName.10 ==        'FE-100'
         entPhysicalAlias.10 ==            ''

         entPhysicalAssetID.10 ==          ''
         entPhysicalIsFRU.10 ==            false(2)
         entPhysicalMfgDate.10 ==          '2002-7-26,13:30:15.0,-4:0'
         entPhysicalUris.10 ==             'URN:CLEI:CNMES23ARA'

         entPhysicalDescr.11 ==            'Acme Ethernet-100 Port'
         entPhysicalVendorType.11 ==       acmeProducts.portTypes.2
         entPhysicalContainedIn.11 ==      8
         entPhysicalClass.11 ==            port(10)
         entPhysicalParentRelPos.11 ==     3
         entPhysicalName.11 ==             'Ethernet B'
         entPhysicalHardwareRev.11 ==      'G(1.04)'
         entPhysicalSoftwareRev.11 ==      ''
         entPhysicalFirmwareRev.11 ==      '1.3'
         entPhysicalSerialNum.11 ==        ''
         entPhysicalMfgName.11 ==          'Acme'
         entPhysicalModelName.11 ==        'FE-100'
         entPhysicalAlias.11 ==            ''
         entPhysicalAssetID.11 ==          ''
         entPhysicalIsFRU.11 ==            false(2)
         entPhysicalMfgDate.11 ==          '2002-8-16,15:35:15.0,-4:0'
         entPhysicalUris.11 ==             'URN:CLEI:CNMES23ARA'

      Logical entities -- entLogicalTable; no SNMPv3 support
       2 OSPF instances:
         entLogicalDescr.1 ==              'Acme OSPF v1.1'
         entLogicalType.1 ==               ospf
         entLogicalCommunity.1 ==          'public-ospf1'
         entLogicalTAddress.1 ==           192.0.2.1:161
         entLogicalTDomain.1 ==            snmpUDPDomain
         entLogicalContextEngineID.1 ==    ''
         entLogicalContextName.1 ==        ''

         entLogicalDescr.2 ==              'Acme OSPF v1.1'
         entLogicalType.2 ==               ospf
         entLogicalCommunity.2 ==          'public-ospf2'
         entLogicalTAddress.2 ==           192.0.2.1:161
         entLogicalTDomain.2 ==            snmpUDPDomain
         entLogicalContextEngineID.2 ==    ''
         entLogicalContextName.2 ==        ''

       2 logical bridges:
         entLogicalDescr.3 ==              'Acme Bridge v2.1.1'
         entLogicalType.3  ==              dot1dBridge
         entLogicalCommunity.3 ==          'public-bridge1'
         entLogicalTAddress.3 ==           192.0.2.1:161
         entLogicalTDomain.3 ==            snmpUDPDomain
         entLogicalContextEngineID.3 ==    ''

         entLogicalContextName.3 ==        ''

         entLogicalDescr.4 ==              'Acme Bridge v2.1.1'
         entLogicalType.4 ==               dot1dBridge
         entLogicalCommunity.4 ==          'public-bridge2'
         entLogicalTAddress.4 ==           192.0.2.1:161
         entLogicalTDomain.4 ==            snmpUDPDomain
         entLogicalContextEngineID.4 ==    ''
         entLogicalContextName.4 ==        ''

   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

     [ed. -- Note that these mappings are included in the table because
     another logical entity (1st OSPF) utilizes one of the
     ports.  If this were not the case, then a single mapping
     to the module (e.g., entLPPhysicalIndex.3.4) would be
     present instead.]
         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

   Physical to Logical to MIB Alias Mappings -- entAliasMappingTable:
     Example 1: ifIndex values are global to all logical entities
         entAliasMappingIdentifier.5.0 ==  ifIndex.1
         entAliasMappingIdentifier.6.0 ==  ifIndex.2
         entAliasMappingIdentifier.7.0 ==  ifIndex.3
         entAliasMappingIdentifier.9.0 ==  ifIndex.4
         entAliasMappingIdentifier.10.0 == ifIndex.5
         entAliasMappingIdentifier.11.0 == ifIndex.6

     Example 2: ifIndex values are not shared by all logical entities;
            (Bridge-1 uses ifIndex values 101 - 103 and Bridge-2 uses
   ifIndex values 204-206.)
            entAliasMappingIdentifier.5.0 ==  ifIndex.1
            entAliasMappingIdentifier.5.3 ==  ifIndex.101
            entAliasMappingIdentifier.6.0 ==  ifIndex.2

            entAliasMappingIdentifier.6.3 ==  ifIndex.102
            entAliasMappingIdentifier.7.0 ==  ifIndex.3
            entAliasMappingIdentifier.7.3 ==  ifIndex.103
            entAliasMappingIdentifier.9.0 ==  ifIndex.4
            entAliasMappingIdentifier.9.4 ==  ifIndex.204
            entAliasMappingIdentifier.10.0 == ifIndex.5
            entAliasMappingIdentifier.10.4 == ifIndex.205
            entAliasMappingIdentifier.11.0 == ifIndex.6
            entAliasMappingIdentifier.11.4 == ifIndex.206

   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 3 ports:
         entPhysicalChildIndex.4.5 ==      5
         entPhysicalChildIndex.4.6 ==      6
         entPhysicalChildIndex.4.7 ==      7

     module 2 has 3 ports:
         entPhysicalChildIndex.8.9 ==      9
         entPhysicalChildIndex.8.10 ==     10
         entPhysicalChildIndex.8.11 ==     11

4.2.  Repeaters

   The second example is a 3-slot Hub with 2 backplane ethernet
   segments.  Slot three is empty, and the remaining slots contain
   ethernet repeater modules.

   Note that this example assumes an older Repeater MIB implementation,
   (RFC 1516 [RFC1516]) rather than the new Repeater MIB (RFC 2108
   [RFC2108]).  The new version contains an object called
   'rptrPortRptrId', which should be used to identify repeater port
   groupings, rather than using community strings or contexts.

   Physical entities -- entPhysicalTable:
      1 Field-replaceable physical chassis:
         entPhysicalDescr.1 ==       'Acme Chassis Model 110'
         entPhysicalVendorType.1 ==  acmeProducts.chassisTypes.2
         entPhysicalContainedIn.1 == 0

         entPhysicalClass.1 ==       chassis(3)
         entPhysicalParentRelPos.1 ==0
         entPhysicalName.1 ==        '110-B'
         entPhysicalHardwareRev.1 == 'A(1.02.00)'
         entPhysicalSoftwareRev.1 == ''
         entPhysicalFirmwareRev.1 == ''
         entPhysicalSerialNum.1 ==   'C100079294'
         entPhysicalMfgName.1 ==     'Acme'
         entPhysicalModelName.1 ==   '110'
         entPhysicalAlias.1 ==       'bldg09:floor1:rptr18:0067eea0229f'
         entPhysicalAssetID.1 ==     '0007386327'
         entPhysicalIsFRU.1 ==       true(1)

      2 Chassis Ethernet Backplanes:
         entPhysicalDescr.2 ==          'Acme Ethernet Backplane Type A'
         entPhysicalVendorType.2 ==     acmeProducts.backplaneTypes.1
         entPhysicalContainedIn.2 ==    1
         entPhysicalClass.2 ==          backplane(4)
         entPhysicalParentRelPos.2 ==   1
         entPhysicalName.2 ==           'B1'
         entPhysicalHardwareRev.2 ==    'A(2.04.01)'
         entPhysicalSoftwareRev.2 ==    ''
         entPhysicalFirmwareRev.2 ==    ''
         entPhysicalSerialNum.2 ==      ''
         entPhysicalMfgName.2 ==        'Acme'
         entPhysicalModelName.2 ==      'BK-A'
         entPhysicalAlias.2 ==          ''
         entPhysicalAssetID.2 ==        ''
         entPhysicalIsFRU.2 ==          false(2)

         entPhysicalDescr.3 ==          'Acme Ethernet Backplane Type A'
         entPhysicalVendorType.3  ==    acmeProducts.backplaneTypes.1
         entPhysicalContainedIn.3 ==    1
         entPhysicalClass.3 ==          backplane(4)
         entPhysicalParentRelPos.3 ==   2
         entPhysicalName.3 ==           'B2'
         entPhysicalHardwareRev.3 ==    'A(2.04.01)'
         entPhysicalSoftwareRev.3 ==    ''
         entPhysicalFirmwareRev.3 ==    ''
         entPhysicalSerialNum.3 ==      ''
         entPhysicalMfgName.3 ==        'Acme'
         entPhysicalModelName.3 ==      'BK-A'
         entPhysicalAlias.3 ==          ''
         entPhysicalAssetID.3 ==        ''
         entPhysicalIsFRU.3 ==          false(2)

      3 slots within the chassis:
         entPhysicalDescr.4 ==          'Acme Hub Slot Type RB'
         entPhysicalVendorType.4  ==    acmeProducts.slotTypes.5
         entPhysicalContainedIn.4 ==    1
         entPhysicalClass.4 ==          container(5)
         entPhysicalParentRelPos.4 ==   1
         entPhysicalName.4 ==           'Slot 1'
         entPhysicalHardwareRev.4 ==    'B(1.00.03)'
         entPhysicalSoftwareRev.4 ==    ''
         entPhysicalFirmwareRev.4 ==    ''
         entPhysicalSerialNum.4 ==      ''
         entPhysicalMfgName.4 ==        'Acme'
         entPhysicalModelName.4 ==      'RB'
         entPhysicalAlias.4 ==          ''
         entPhysicalAssetID.4 ==        ''
         entPhysicalIsFRU.4 ==          false(2)

         entPhysicalDescr.5 ==          'Acme Hub Slot Type RB'
         entPhysicalVendorType.5  ==    acmeProducts.slotTypes.5
         entPhysicalContainedIn.5 ==    1
         entPhysicalClass.5 ==          container(5)
         entPhysicalParentRelPos.5 ==   2
         entPhysicalName.5 ==           'Slot 2'
         entPhysicalHardwareRev.5 ==    'B(1.00.03)'
         entPhysicalSoftwareRev.5 ==    ''
         entPhysicalFirmwareRev.5 ==    ''
         entPhysicalSerialNum.5 ==      ''
         entPhysicalMfgName.5 ==        'Acme'
         entPhysicalModelName.5 ==      'RB'
         entPhysicalAlias.5 ==          ''
         entPhysicalAssetID.5 ==        ''
         entPhysicalIsFRU.5 ==          false(2)

         entPhysicalDescr.6 ==          'Acme Hub Slot Type RB'
         entPhysicalVendorType.6  ==    acmeProducts.slotTypes.5
         entPhysicalContainedIn.6 ==    1
         entPhysicalClass.6 ==          container(5)
         entPhysicalParentRelPos.6 ==   3
         entPhysicalName.6 ==           'Slot 3'
         entPhysicalHardwareRev.6 ==    'B(1.00.03)'
         entPhysicalSoftwareRev.6 ==    ''
         entPhysicalFirmwareRev.6 ==    ''
         entPhysicalSerialNum.6 ==      ''
         entPhysicalMfgName.6 ==        'Acme'
         entPhysicalModelName.6 ==      'RB'
         entPhysicalAlias.6 ==          ''
         entPhysicalAssetID.6 ==        ''
         entPhysicalIsFRU.6 ==          false(2)

      Slot 1 contains a plug-in module with 4 10-BaseT ports:
         entPhysicalDescr.7  ==         'Acme 10Base-T Module 114'
         entPhysicalVendorType.7 ==     acmeProducts.moduleTypes.32
         entPhysicalContainedIn.7  ==   4
         entPhysicalClass.7 ==          module(9)
         entPhysicalParentRelPos.7 ==   1
         entPhysicalName.7 ==           'M1'
         entPhysicalHardwareRev.7 ==    'A(1.02.01)'
         entPhysicalSoftwareRev.7 ==    '1.7.2'
         entPhysicalFirmwareRev.7 ==    'A(1.5)'
         entPhysicalSerialNum.7 ==      'C100096244'
         entPhysicalMfgName.7 ==        'Acme'
         entPhysicalModelName.7 =       '114'
         entPhysicalAlias.7 ==          'bldg09:floor1:eng'
         entPhysicalAssetID.7 ==        '0007962951'
         entPhysicalIsFRU.7 ==          true(1)

         entPhysicalDescr.8 ==          'Acme 10Base-T Port RB'
         entPhysicalVendorType.8 ==     acmeProducts.portTypes.10
         entPhysicalContainedIn.8  ==   7
         entPhysicalClass.8 ==          port(10)
         entPhysicalParentRelPos.8 ==   1
         entPhysicalName.8 ==           'Ethernet-A'
         entPhysicalHardwareRev.8 ==    'A(1.04F)'
         entPhysicalSoftwareRev.8 ==    ''
         entPhysicalFirmwareRev.8 ==    '1.4'
         entPhysicalSerialNum.8 ==      ''
         entPhysicalMfgName.8 ==        'Acme'
         entPhysicalModelName.8 ==      'RB'
         entPhysicalAlias.8 ==          ''
         entPhysicalAssetID.8 ==        ''
         entPhysicalIsFRU.8 ==          false(2)

         entPhysicalDescr.9  ==         'Acme 10Base-T Port RB'
         entPhysicalVendorType.9 ==     acmeProducts.portTypes.10
         entPhysicalContainedIn.9 ==    7
         entPhysicalClass.9 ==          port(10)
         entPhysicalParentRelPos.9 ==   2
         entPhysicalName.9 ==           'Ethernet-B'
         entPhysicalHardwareRev.9 ==    'A(1.04F)'
         entPhysicalSoftwareRev.9 ==    ''
         entPhysicalFirmwareRev.9 ==    '1.4'
         entPhysicalSerialNum.9 ==      ''
         entPhysicalMfgName.9 ==        'Acme'
         entPhysicalModelName.9 =       'RB'
         entPhysicalAlias.9 ==          ''
         entPhysicalAssetID.9 ==        ''
         entPhysicalIsFRU.9 ==          false(2)

         entPhysicalDescr.10 ==         'Acme 10Base-T Port RB'
         entPhysicalVendorType.10 ==    acmeProducts.portTypes.10
         entPhysicalContainedIn.10 ==   7
         entPhysicalClass.10 ==         port(10)
         entPhysicalParentRelPos.10 ==  3
         entPhysicalName.10 ==          'Ethernet-C'
         entPhysicalHardwareRev.10 ==   'B(1.02.07)'
         entPhysicalSoftwareRev.10 ==   ''
         entPhysicalFirmwareRev.10 ==   '1.4'
         entPhysicalSerialNum.10 ==     ''
         entPhysicalMfgName.10 ==       'Acme'
         entPhysicalModelName.10 ==     'RB'
         entPhysicalAlias.10 ==         ''
         entPhysicalAssetID.10 ==       ''
         entPhysicalIsFRU.10 ==         false(2)

         entPhysicalDescr.11 ==         'Acme 10Base-T Port RB'
         entPhysicalVendorType.11  ==   acmeProducts.portTypes.10
         entPhysicalContainedIn.11 ==   7
         entPhysicalClass.11 ==         port(10)
         entPhysicalParentRelPos.11 ==  4
         entPhysicalName.11 ==          'Ethernet-D'
         entPhysicalHardwareRev.11 ==   'B(1.02.07)'
         entPhysicalSoftwareRev.11 ==   ''
         entPhysicalFirmwareRev.11 ==   '1.4'
         entPhysicalSerialNum.11 ==     ''
         entPhysicalMfgName.11 ==       'Acme'
         entPhysicalModelName.11 ==     'RB'
         entPhysicalAlias.11 ==         ''
         entPhysicalAssetID.11 ==       ''
         entPhysicalIsFRU.11 ==         false(2)

      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
         entPhysicalName.12 ==          'M2'
         entPhysicalHardwareRev.12 ==   'A(1.01.07)'
         entPhysicalSoftwareRev.12 ==   '1.8.4'
         entPhysicalFirmwareRev.12 ==   'A(1.8)'
         entPhysicalSerialNum.12 ==     'C100102384'
         entPhysicalMfgName.12 ==       'Acme'
         entPhysicalModelName.12 ==     '4'
         entPhysicalAlias.12 ==         'bldg09:floor1:devtest'
         entPhysicalAssetID.12 ==       '0007968462'
         entPhysicalIsFRU.12 ==         true(1)

         entPhysicalDescr.13 ==         'Acme 802.3 AUI Port'
         entPhysicalVendorType.13  ==   acmeProducts.portTypes.11
         entPhysicalContainedIn.13 ==   12
         entPhysicalClass.13 ==         port(10)
         entPhysicalParentRelPos.13 ==  1
         entPhysicalName.13 ==          'AUI'
         entPhysicalHardwareRev.13 ==   'A(1.06F)'
         entPhysicalSoftwareRev.13 ==   ''
         entPhysicalFirmwareRev.13 ==   '1.5'
         entPhysicalSerialNum.13 ==     ''
         entPhysicalMfgName.13 ==       'Acme'
         entPhysicalModelName.13 ==     ''
         entPhysicalAlias.13 ==         ''
         entPhysicalAssetID.13 ==       ''
         entPhysicalIsFRU.13 ==         false(2)

         entPhysicalDescr.14 ==         'Acme 10Base-T Port RD'
         entPhysicalVendorType.14  ==   acmeProducts.portTypes.14
         entPhysicalContainedIn.14 ==   12
         entPhysicalClass.14 ==         port(10)
         entPhysicalParentRelPos.14 ==  2
         entPhysicalName.14 ==          'E2'
         entPhysicalHardwareRev.14 ==   'B(1.01.02)'
         entPhysicalSoftwareRev.14 ==   ''
         entPhysicalFirmwareRev.14 ==   '2.1'
         entPhysicalSerialNum.14 ==     ''
         entPhysicalMfgName.14 ==       'Acme'
         entPhysicalModelName.14 ==     ''
         entPhysicalAlias.14 ==         ''
         entPhysicalAssetID.14 ==       ''
         entPhysicalIsFRU.14 ==         false(2)

   Logical entities -- entLogicalTable; with SNMPv3 support
      Repeater 1--comprised of any ports attached to backplane 1
         entLogicalDescr.1 ==           'Acme repeater v3.1'
         entLogicalType.1  ==           snmpDot3RptrMgt
         entLogicalCommunity.1          'public-repeater1'
         entLogicalTAddress.1 ==        192.0.2.1:161
         entLogicalTDomain.1 ==         snmpUDPDomain
         entLogicalContextEngineID.1 == '80000777017c7d7e7f'H
         entLogicalContextName.1 ==     'repeater1'

      Repeater 2--comprised of any ports attached to backplane 2:
         entLogicalDescr.2 ==           'Acme repeater v3.1'
         entLogicalType.2  ==           snmpDot3RptrMgt
         entLogicalCommunity.2 ==       'public-repeater2'
         entLogicalTAddress.2 ==        192.0.2.1:161
         entLogicalTDomain.2 ==         snmpUDPDomain

         entLogicalContextEngineID.2 == '80000777017c7d7e7f'H
         entLogicalContextName.2 ==     'repeater2'

   Logical to Physical Mappings -- entLPMappingTable:

     repeater1 uses backplane 1, slot 1-ports 1 & 2, slot 2-port 1
     [ed. -- Note that a mapping to the module is not included,
      because this example represents a port-switchable hub.
      Even though all ports on the module could belong to the
      same repeater as a matter of configuration, the LP port
      mappings should not be replaced dynamically with a single
      mapping for the module (e.g., entLPPhysicalIndex.1.7).
      If all ports on the module shared a single backplane connection,
      then a single mapping for the module would be more appropriate.]

        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

   Physical to Logical to MIB Alias Mappings -- entAliasMappingTable:
     Repeater Port Identifier values are shared by both repeaters:
         entAliasMappingIdentifier.8.0 ==      rptrPortGroupIndex.1.1
         entAliasMappingIdentifier.9.0 ==      rptrPortGroupIndex.1.2
         entAliasMappingIdentifier.10.0 ==     rptrPortGroupIndex.1.3
         entAliasMappingIdentifier.11.0 ==     rptrPortGroupIndex.1.4
         entAliasMappingIdentifier.13.0 ==     rptrPortGroupIndex.2.1
         entAliasMappingIdentifier.14.0 ==     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
         entPhysicalChildIndex.1.6 ==   6

     container 1 has a module:
         entPhysicalChildIndex.4.7 ==   7

     container 2 has a module
         entPhysicalChildIndex.5.12 ==  12

     [ed. -- in this example, container 3 is empty.]

     module 1 has 4 ports:
         entPhysicalChildIndex.7.8 ==   8
         entPhysicalChildIndex.7.9 ==   9
         entPhysicalChildIndex.7.10 ==  10
         entPhysicalChildIndex.7.11 ==  11

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

5.  Security Considerations

   There are a number of management objects defined in this MIB that
   have a MAX-ACCESS clause of read-write and/or read-create.  Such
   objects may be considered sensitive or vulnerable in some network
   environments.  The support for SET operations in a non-secure
   environment without proper protection can have a negative effect on
   network operations.

   There are a number of managed objects in this MIB that may contain
   sensitive information.  These are:

   entPhysicalDescr
   entPhysicalVendorType
   entPhysicalHardwareRev
   entPhysicalFirmwareRev
   entPhysicalSoftwareRev
   entPhysicalSerialNum
   entPhysicalMfgName
   entPhysicalModelName

      These objects expose information about the physical entities
      within a managed system, which may be used to identify the vendor,
      model, and version information of each system component.

   entPhysicalAssetID

      This object can allow asset identifiers for various system
      components to be exposed, in the event this MIB object is actually
      configured by an NMS application.

   entLogicalDescr
   entLogicalType

      These objects expose the type of logical entities present in the
      managed system.

   entLogicalCommunity

      This object exposes community names associated with particular
      logical entities within the system.

   entLogicalTAddress
   entLogicalTDomain

      These objects expose network addresses that can be used to
      communicate with an SNMP agent on behalf of particular logical
      entities within the system.

   entLogicalContextEngineID
   entLogicalContextName

      These objects identify the authoritative SNMP engine that contains
      information on behalf of particular logical entities within the
      system.

   It is thus important to control even GET access to these objects
   and possibly to even encrypt the values of these object when
   sending them over the network via SNMP.  Not all versions of SNMP
   provide features for such a secure environment.

   SNMPv1 by itself is not a secure environment.  Even if the network
   itself is secure (for example by using IPSec), even then, there is
   no control as to who on the secure network is allowed to access and
   GET/SET (read/change/create/delete) the objects in this MIB.

   It is recommended that the implementers consider the security
   features as provided by the SNMPv3 framework.  Specifically, the
   use of the User-based Security Model RFC 3414 [RFC3414] and the
   View-based Access Control Model RFC 3415 [RFC3415] is recommended.

   It is then a customer/user responsibility to ensure that the SNMP
   entity giving access to an instance of this MIB, is properly
   configured to give access to the objects only to those principals
   (users) that have legitimate rights to indeed GET or SET
   (change/create/delete) them.

6.  IANA Considerations

   The MIB module in this document uses the following IANA-assigned
   OBJECT IDENTIFIER values recorded in the SMI Numbers registry:

              Descriptor        OBJECT IDENTIFIER value
              ----------        -----------------------
              entityMIB         { mib-2 47 }

7.  Acknowledgements

   This memo has been produced by the IETF's Entity MIB working group.

8.  References

8.1.  Normative References

   [RFC2578]     McCloghrie, K., Perkins, D., and J. Schoenwaelder,
                 "Structure of Management Information Version 2
                 (SMIv2)", STD 58, RFC 2578, April 1999.

   [RFC2579]     McCloghrie, K., Perkins, D., and J. Schoenwaelder,
                 "Textual Conventions for SMIv2", STD 58, RFC 2579,
                 April 1999.

   [RFC2580]     McCloghrie, K., Perkins, D., and J. Schoenwaelder,
                 "Conformance Statements for SMIv2", STD 58, RFC 2580,
                 April 1999.

   [RFC3411]     Harrington, D., Presuhn, R., and B. Wijnen, "An
                 Architecture for Describing Simple Network Management
                 Protocol (SNMP) Management Frameworks", STD 62, RFC
                 3411, December 2002.

   [RFC3417]     Presuhn, R., "Transport Mappings for the Simple Network
                 Management Protocol (SNMP)", STD 62, RFC 3417, December
                 2002.

   [RFC3986]     Berners-Lee, T., Fielding, R., and L. Masinter,
                 "Uniform Resource Identifier (URI): Generic Syntax",
                 STD 66, RFC 3986, January 2005.

8.2.  Informative References

   [RFC1157]     Case, J., Fedor, M., Schoffstall, M., and J. Davin,
                 "Simple Network Management Protocol", STD 15, RFC 1157,
                 May 1990.

   [RFC1493]     Decker, E., Langille, P., Rijsinghani, A., and K.
                 McCloghrie, "Definitions of Managed Objects for
                 Bridges", RFC 1493, July 1993.

   [RFC1516]     McMaster, D. and K. McCloghrie, "Definitions of Managed
                 Objects for IEEE 802.3 Repeater Devices", RFC 1516,
                 September 1993.

   [RFC2037]     McCloghrie, K. and A. Bierman, "Entity MIB using
                 SMIv2", RFC 2037, October 1996.

   [RFC2108]     de Graaf, K., Romascanu, D., McMaster, D., and K.
                 McCloghrie, "Definitions of Managed Objects for IEEE
                 802.3 Repeater Devices using SMIv2", RFC 2108, February
                 1997.

   [RFC2737]     McCloghrie, K. and A. Bierman, "Entity MIB (Version
                 2)", RFC 2737, December 1999.

   [RFC2863]     McCloghrie, K. and F. Kastenholz, "The Interfaces Group
                 MIB", RFC 2863, June 2000.

   [RFC3406]     Daigle, L., van Gulik, D., Iannella, R., and P.
                 Faltstrom, "Uniform Resource Names (URN) Namespace
                 Definition Mechanisms", BCP 66, RFC 3406, October 2002.

   [RFC3410]     Case, J., Mundy, R., Partain, D., and B. Stewart,
                 "Introduction and Applicability Statements for
                 Internet-Standard Management Framework", RFC 3410,
                 December 2002.

   [RFC3414]     Blumenthal, U. and B. Wijnen, "User-based Security
                 Model (USM) for version 3 of the Simple Network
                 Management Protocol (SNMPv3)", STD 62, RFC 3414,
                 December 2002.

   [RFC3415]     Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based
                 Access Control Model (VACM) for the Simple Network
                 Management Protocol (SNMP)", STD 62, RFC 3415, December
                 2002.

   [RFC4152]     Tesink, K. and R. Fox, "A Uniform Resource Name (URN)
                 Namespace for the CLEI Code", RFC 4152, August 2005.

   [T1.213]      ATIS T1.213-2001, "Coded Identification of Equipment
                 Entities in the North American Telecommunications
                 System for Information Exchange", 2001, www.ansi.org.

   [T1.213a]     ATIS T1.213a, "Supplement to T1.213-2001, Coded
                 Identification of Equipment Entities in the North
                 American Telecommunications System for Information
                 Exchange, to correct the representation of the Basic
                 Code in Figure B.1", 2001, www.ansi.org.

Authors' Addresses

   Andy Bierman

   EMail: ietf@andybierman.com

   Keith McCloghrie
   Cisco Systems, Inc.
   170 West Tasman Drive
   San Jose, CA 95134 USA

   Phone: +1 408-526-5260
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