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Versions: 00 01 02 03 04 05 06 rfc2737                                  
Entity MIB Working Group                               Keith McCloghrie
Internet Draft                                       Cisco Systems, Inc.
                                                           Andy Bierman
                                                     Cisco Systems, Inc.
                                                         05 August 1998


                   Entity MIB using SMIv2 (Version 2)


                     <draft-ietf-entmib-v2-00.txt>





Status of this Memo

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

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

To view the entire list of current Internet-Drafts, please check the
"1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
Directories on ftp.is.co.za (Africa), ftp.nordu.net (Northern Europe),
ftp.nis.garr.it (Southern Europe), munnari.oz.au (Pacific Rim),
ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast).

Distribution of this document is unlimited. Please send comments to the
Entity MIB Working Group, <entmib@cisco.com>.


1.  Copyright Notice

Copyright (C) The Internet Society (1998).  All Rights Reserved.















Internet Draft           Entity MIB (Version 2)              August 1998


2.  Abstract

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


3.  The SNMP Network Management Framework

The SNMP Management Framework presently consists of five major
components:

   - An overall architecture, described in RFC 2271 [1].

   - Mechanisms for describing and naming objects and events for the
     purpose of management. The first version of this Structure of
     Management Information (SMI) is called SMIv1 and described in RFC
     1155 [2], RFC 1212 [3] and RFC 1215 [4]. The second version, called
     SMIv2, is described in RFC 1902 [5], RFC 1903 [6] and RFC 1904 [7].

   - Message protocols for transferring management information. The
     first version of the SNMP message protocol is called SNMPv1 and
     described in RFC 1157 [8]. A second version of the SNMP message
     protocol, which is not an Internet standards track protocol, is
     called SNMPv2c and described in RFC 1901 [9] and RFC 1906 [10].
     The third version of the message protocol is called SNMPv3 and
     described in RFC 1906 [10], RFC 2272 [11] and RFC 2274 [12].

   - Protocol operations for accessing management information. The first
     set of protocol operations and associated PDU formats is described
     in RFC 1157 [8]. A second set of protocol operations and associated
     PDU formats is described in RFC 1905 [13].

   - A set of fundamental applications described in RFC 2273 [14] and
     the view-based access control mechanism described in RFC 2275 [15].

Managed objects are accessed via a virtual information store, termed the
Management Information Base or MIB.  Objects in the MIB are defined
using the mechanisms defined in the SMI.

This memo specifies a MIB module that is compliant to the SMIv2. A MIB
conforming to the SMIv1 can be produced through the appropriate
translations. The resulting translated MIB must be semantically





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equivalent, except where objects or events are omitted because no
information in SMIv2 will be converted into textual descriptions in
SMIv1 during the translation process. However, this loss of machine
readable information is not considered to change the semantics of the
MIB.

4.  Overview

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

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

   - multiple repeaters supported by a single agent;

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

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

What is needed is a way to determine exactly what logical entities are
managed by the agent (either by SNMPv1, SNMPv2C, or SNMPv3), and thereby
to be able to communicate with the agent about a particular logical
entity.  When different logical entities are associated with different
physical entities within the overall physical entity, it is also useful
to be able to use this information to distinguish between logical
entities.

In these situations, there is no need for varbinds for multiple logical
entities to be referenced in the same 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.





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Version 2 of this MIB addresses new requirements that have emerged since
the publication of the first Entity MIB (RFC 2037 [16]).  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 [1]. Implementation experience has shown that
additional physical component attributes are also needed.


4.1.  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 2271 [1].

   - 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. It is an implementation-specific manner as to which physical
     components are represented by an agent in the EntPhysicalTable.





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     Typically, physical resources (e.g. communications ports,
     backplanes, sensors, daughter-cards, power supplies, the overall
     chassis) which can be managed via functions associated with one or
     more logical entities are included in the MIB.

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

     Note that chassis slots, which are capable of accepting one or more
     module types from one or more vendors, are modeled as containers in
     this MIB. The value of entPhysicalContainedIn for a particular
     'module' entity (entPhysicalClass value of 'module(9)') must be
     equal to an entPhysicalIndex that represents the parent 'container'
     entity (associated entPhysicalClass value of ('container(5)'). An
     agent must represent both empty and full containers in the
     entPhysicalTable.

4.2.  Relationship to Community Strings

For community-based SNMP, distinguishing between different logical
entities is one (but not the only) purpose of the community string [8].
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.

4.3.  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.





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4.4.  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. An 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 a network administrator will likely be able to associate
community strings with naming scopes with proprietary mechanisms, as a
matter of configuration. There are no mechanisms for managing naming
scopes defined in this MIB.


4.5.  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.


4.6.  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 [17]. Since 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 [17], for all types of





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physical components.


4.7.  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.


4.8.  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 'main' naming scope).

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 'main' naming scope, as well as a
second instance of the Bridge MIB.

It is an implementation-specific matter as to the isolation of single-
scoped MIB objects by the agent. An agent may wish to limit the objects
returned in a particular naming scope to just 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. 'main'), which itself may contain some multi-scoped
objects (e.g. system group).

4.9.  Multiple Instances of the Entity MIB

It is possible that more than one agent exists in a managed system, and
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





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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.


4.10.  Re-Configuration of Entities

Most of the MIB objects defined in this MIB have at most a read-only
MAX-ACCESS clause, i.e., none are write-able.  This is a conscious
decision by the working group to limit this MIB's scope.  The second
version of the Entity MIB allows an network administrator to configure
some common attributes of physical components.


4.11.  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.







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

  - entityNotifications group
     Contains status indication notifications.


4.11.1.  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 contains at least one row for an "overall" physical entity.  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 choose to 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 removeable 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 which 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 is a writeable object in case
     an agent cannot identify the serial numbers of all installed
     physical entities, and a network administrator wishes to configure





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     the non-volatile serial number strings manually (via an NMS
     application).

4.11.2.  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
SNMPv1 [6], SNMPv2C [9], or SNMPv3 [1]  access to the MIB information
for the logical entity.

4.11.3.  entityMapping Group

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

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

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

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

4.11.4.  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





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part of the system configuration last changed.

4.11.5.  entityNotifications Group

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

4.12.  Multiple Agents

Even though a primary motivation for this MIB is to represent the
multiple logical entities supported by a single agent, it is also
possible to use it to represent multiple logical entities supported by
multiple agents (in the same "overall" physical entity).  Indeed, it is
implicit in the 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 which should be expected for agent implementations.
Therefore, multiple agents within the same managed system are free to
implement the Entity MIB independently.  (Refer the section on "Multiple
Instances of the Entity MIB" for more details).

4.13.  Change Log

The following changes have been made since publication of the original
Entity MIB [16].

4.13.1.  Version 00

  -  Clarified description of the PhysicalClass textual convention.
     Added a new enumeration.

  -  Added RevisionString and SnmpEngineIdOrZero textual conventions to
     support new entPhysicalTable and entLogicalTable objects

  -  Fixed bug in entPhysicalParentRelPos DESCRIPTION clause

  -  Added entPhysicalHardwareRev, FirmwareRev, and SoftwareRev objects
     for revision identification

  -  Added entPhysicalMfgName and entPhysicalModelName objects for
     better component identification

  -  Added entPhysicalAlias read-write string to identify specific
     components across reboots.





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  -  Added entPhysicalAssetID and entPhysicalSerialNum read-write
     strings to allow user identification of specific components across
     reboots.

  -  Fixed a bug 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.

  -  Added entLogicalContextEngineID and entLogicalContextName objects
     to provide an SNMP context for SNMPv3 access on behalf of a logical
     entity.

  -  Changed entLastChangeTime object description to generalize the
     events which cause an update to the last change timestamp.

5.  Definitions

ENTITY-MIB DEFINITIONS ::= BEGIN

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

entityMIB MODULE-IDENTITY
    LAST-UPDATED "9808050000Z"
    ORGANIZATION "IETF ENTMIB Working Group"
    CONTACT-INFO
            "        WG E-mail: entmib@cisco.com
                     Subscribe: majordomo@cisco.com
                                msg body: subscribe entmib

                     Keith McCloghrie
                     ENTMIB Working Group Chair
                     Cisco Systems Inc.
                     170 West Tasman Drive
                     San Jose, CA 95134
                     408-526-5260
                     kzm@cisco.com





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                     Andy Bierman
                     ENTMIB Working Group Editor
                     Cisco Systems Inc.
                     170 West Tasman Drive
                     San Jose, CA 95134
                     408-527-3711
                     abierman@cisco.com"
    DESCRIPTION
            "The MIB module for representing multiple logical
            entities supported by a single SNMP agent."
    ::= { 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
    STATUS          current
    DESCRIPTION
            "An arbitrary value which uniquely identifies the physical
            entity.  The value is a small positive integer; index values
            for different physical entities are not necessarily
            contiguous."
    SYNTAX          INTEGER (1..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.






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            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 chasis may only be
            contained within a stack.  (The phrase 'within class X'
            indicates an entPhysicalEntry with a entPhysicalContainedIn
            value identical to the entPhysicalIndex for a particular
            physical entity, of entPhysicalClass 'X'.)

            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.

            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 removeable physical entities should
            be modeled within a container entity, such as field-
            replaceable modules, fans, power supplies, etc.

            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
            it is removeable, then it should be modeled within a
            container entity, otherwise it may 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.





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            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 a virtual cable, or be a real interconnect
            cable, attached to multiple chassis, or may in fact be
            comprised of multiple interconnect cables. A stack may not
            be modeled within any other entity class, and only chassis
            entities may be contained within a stack."
    SYNTAX      INTEGER  {
        other(1),
        unknown(2),
        chassis(3),
        backplane(4),
        container(5),     -- e.g., 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
    }

RevisionString ::= TEXTUAL-CONVENTION
    STATUS          current
    DESCRIPTION
            "A specially formatted SnmpAdminString which contains one or
            more revision identifier strings.  This string has the
            encoding rules as those defined in the SnmpAdminString
            textual convention (see RFC 2271 [1]), with some additional
            restrictions.

            The actual semantics and contents of an individual revision
            string are vendor-specific, and not defined by this TC.

            Some encoding rules to improve readability are defined:

                 If more than one revision applies to a particular
                 physical entity, a field separator must be present
                 between each revision string.  The same field separator
                 must be used throughout the string, and only a single
                 instance of the field separator is allowed between
                 revision strings. Leading and trailing field separators
                 are not allowed.

                 No one mandatory field separator value is defined, but





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                 the value must be one of following sequences:

                      Name       '<ch>[<ch2>]'   (Decimal)
                      -------------------------------------
                      space (SP)  ' '             (32)
                      comma       ','             (44)
                      semicolon   ';'             (59)
                      colon       ':'             (58)
                      newline     CR LF           (13 10)
                      field sep.  FS              (28)

                 If a revision string contains binary numbers (in its
                 native encoding), then such numbers must be converted
                 to a printable format before they can be returned in a
                 RevisionString-based MIB object.

                 A hexadecimal prefix (e.g., '0x') is not explicitly
                 defined, and is not mandatory.

                 Each binary octet is first separated into two binary
                 nibbles. The higher-valued 4 bits are printed as the
                 leftmost character, and the lower-valued 4 bits are
                 printed as the rightmost character.

                 Each binary nibble is converted to a printable
                 character using the following table:

                     Binary Value       ASCII (Decimal) Value
                     ----------------------------------------
                        0 - 9            '0' (48)  - '9' (57)
                        10               'A' (65) or 'a' (97)
                        11               'B' (66) or 'b' (98)
                        12               'C' (67) or 'c' (99)
                        13               'D' (68) or 'd' (100)
                        14               'E' (69) or 'e' (101)
                        15               'F' (70) or 'f' (102)

                 For example, a printable hexidecimal string
                 representing the decimal value 100 would be printed as
                 an ASCII string containing the two octet sequence '64'
                 (decimal 54 52).

            If no suitable revision string exists for a particular
            physical entity, then a RevisionString-based MIB object may
            contain a zero-length octet string."





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    SYNTAX      OCTET STRING (SIZE(0..255))   -- SnmpAdminString


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

            If an instance of an object of SYNTAX SnmpEngineIdOrZero has
            a non-zero length, then the object encoding and semantics
            are defined by the SnmpEngineID textual convention (see RFC
            2271 [1]).

            If an instance of an object of SYNTAX SnmpEngineIdOrZero
            contains a zero-length string, then no appropriate
            SnmpEngineID is associated with the logical entity (e.g.,
            SNMPv3 not supported), or no such string may be returned to
            the caller (e.g., insufficient access rights)."
    SYNTAX    OCTET STRING (SIZE(0..32)) -- null 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





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            table."
    INDEX   { entPhysicalIndex }
    ::= { entPhysicalTable 1 }

EntPhysicalEntry ::= SEQUENCE {
      entPhysicalIndex          PhysicalIndex,
      entPhysicalDescr          DisplayString,
      entPhysicalVendorType     AutonomousType,
      entPhysicalContainedIn    INTEGER,
      entPhysicalClass          PhysicalClass,
      entPhysicalParentRelPos   INTEGER,
      entPhysicalName           DisplayString,
      entPhysicalHardwareRev    RevisionString,
      entPhysicalFirmwareRev    RevisionString,
      entPhysicalSoftwareRev    RevisionString,
      entPhysicalSerialNum      SnmpAdminString,
      entPhysicalMfgName        SnmpAdminString,
      entPhysicalModelName      SnmpAdminString,
      entPhysicalAlias          SnmpAdminString,
      entPhysicalAssetID        SnmpAdminString
}

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

entPhysicalDescr OBJECT-TYPE
    SYNTAX      DisplayString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "A textual description of physical entity.  This object
            should contain a string which 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





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    STATUS      current
    DESCRIPTION
            "An indication of the vendor-specific hardware type of the
            physical entity. Note that this is different from the
            definition of MIB-II's sysObjectID.

            An agent should set this object to a enterprise-specific
            registration identifier value indicating the specific
            equipment type in detail.  The associated instance of
            entPhysicalClass 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      INTEGER (0..2147483647)
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The value of entPhysicalIndex for the physical entity which
            'contains' this physical entity.  A value of zero indicates
            this physical entity is not contained in any other physical
            entity.  Note that the set of 'containment' relationships
            define a strict hierarchy; that is, recursion is not
            allowed."
    ::= { entPhysicalEntry 4 }

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

            If no appropriate standard registration identifier exists
            for this physical entity, then the value 'other(1)' is





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            returned. If the value is unknown by this agent, then the
            value 'unknown(2)' is returned."
    ::= { entPhysicalEntry 5 }

entPhysicalParentRelPos OBJECT-TYPE
    SYNTAX      INTEGER (-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 which 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).

            This value should match any external labeling of the
            physical component if possible. 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 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





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            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 a
            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      DisplayString
    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, such as `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 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      RevisionString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION





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            "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).

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

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

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

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

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

entPhysicalSerialNum   OBJECT-TYPE
    SYNTAX      SnmpAdminString
    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).





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            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 which 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 which are permanently
            'contained in' another physical entity (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.

            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 which result 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).

            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 }





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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
            model name string actually printed on the component itself
            (if present).

            If the model name string is 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 an physical entity, the value
            of entPhysicalAlias associated with that entity is set to
            the zero-length string. However, agent may choose to 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 which result in a change of the physical
            entity's entPhysicalIndex value."
    ::= { entPhysicalEntry 14 }

entPhysicalAssetID OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-write
    STATUS      current





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    DESCRIPTION
            "This object is a user-assigned asset tracking identifier
            for the physical entity as specified by a network manager,
            and provides non-volatile storage of this information.

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

            Not every physical component will have a asset tracking
            identifier, or even need one. Physical entities which are
            permanently 'contained in' another physical entity (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 which result 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 }

--           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.  At least
            one entry must exist."
    ::= { entityLogical 1 }

entLogicalEntry       OBJECT-TYPE
    SYNTAX      EntLogicalEntry
    MAX-ACCESS  not-accessible





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    STATUS      current
    DESCRIPTION
            "Information about a particular logical entity.  Entities
            may be managed by this agent or other SNMP agents (possibly)
            in the same chassis."
    INDEX       { entLogicalIndex }
    ::= { entLogicalTable 1 }

EntLogicalEntry ::= SEQUENCE {
      entLogicalIndex            INTEGER,
      entLogicalDescr            DisplayString,
      entLogicalType             AutonomousType,
      entLogicalCommunity        OCTET STRING,
      entLogicalTAddress         TAddress,
      entLogicalTDomain          TDomain,
      entLogicalContextEngineID  SnmpEngineIdOrZero,
      entLogicalContextName      SnmpAdminString
}

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

entLogicalDescr OBJECT-TYPE
    SYNTAX      DisplayString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "A textual description of the logical entity.  This object
            should contain a string which 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





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    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 choose to return a community string
            based on the privileges of the request used to read this
            object.  Note that an agent may choose to 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 which
            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 'main'
            naming scope.  This is possible when the logical entities
            represented by the same value of entLogicalCommunity have no
            object instances in common.  For example, 'bridge1' and
            'repeater1' may be part of the main naming scope, but 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 'main'
            naming scope.

            For agents not accessible via SNMPv1 or SNMPv2C, the value





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            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 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 containing the IP-address in network-byte order and
            the last 2 containing the UDP port in network-byte order.
            Consult 'Transport Mappings for Version 2 of the Simple
            Network Management Protocol' (RFC 1906 [8]) 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 SNMPv2 document (RFC 1906 [8])."
    ::= { entLogicalEntry 6 }

entLogicalContextEngineID    OBJECT-TYPE
    SYNTAX      SnmpEngineIdOrZero





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    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The authoritative contextEngineID that can be used to send
            an SNMPv3 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.

            If SNMPv3 access is not available, no value has been
            configured by the agent, or access control does not permit a
            SNMP Engine ID to be returned for a particular request, a
            zero-length string is returned."
    ::= { entLogicalEntry 7 }

entLogicalContextName    OBJECT-TYPE
    SYNTAX      SnmpAdminString
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The contextName that can be used to send an SNMPv3 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.

            If SNMPv3 access is not available, no value has been
            configured by the agent, or access control does not permit a
            context name to be returned for a particular request, a
            zero-length string is returned."
    ::= { 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





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            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 which
            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 (since the
            entPhysicalContainedIn hierarchy can provide the same
            information). If, on the other hand, more than one bridge
            was 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 {





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      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 which represent
            physical ports (i.e. associated entPhysicalClass value is
            'port(10)') are permitted to exist in this table."





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    INDEX { entPhysicalIndex, entAliasLogicalIndexOrZero }
    ::= { entAliasMappingTable 1 }

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

entAliasLogicalIndexOrZero OBJECT-TYPE
    SYNTAX      INTEGER (0..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "The value of this object uniquely identifies the logical
            entity which 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 which 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





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            index values have precedence over any zero-indexed entry. 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.

            Since only physical ports are modeled in this table, only
            entries which 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 which exposes the container/containee relationships





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            between physical entities. This table provides equivalent
            information found by constructing the virtual containment
            tree for a given entPhysicalTable but in a more direct
            format."
    ::= { 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 }






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

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

            An agent must not generate more than one entConfigChange
            'trap-event' in a five second period, where a 'trap-event'
            is the transmission of a single trap PDU to a list of trap
            destinations.  If additional configuration changes occur
            within the five second 'throttling' period, then these
            trap-events should be suppressed by the agent. An NMS should
            periodically check the value of entLastChangeTime to detect
            any missed entConfigChange trap-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  current
    DESCRIPTION
            "The compliance statement for SNMP entities which implement
            the Entity MIB."
    MODULE  -- this module
        MANDATORY-GROUPS { entityPhysicalGroup,
                           entityLogicalGroup,
                           entityMappingGroup,
                           entityGeneralGroup,
                           entityNotificationsGroup }
    ::= { entityCompliances 1 }

entity2Compliance MODULE-COMPLIANCE
    STATUS  current





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    DESCRIPTION
            "The compliance statement for SNMP entities which implement
            version 2 of the Entity MIB."
    MODULE  -- this module
        MANDATORY-GROUPS { entityPhysicalGroup,
                           entityPhysical2Group,
                           entityLogicalGroup,
                           entityLogical2Group,
                           entityMappingGroup,
                           entityGeneralGroup,
                           entityNotificationsGroup }

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

            Write access is not required for agents which 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 which are
            permanently contained within another physical entity."

        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 which
            cannot provide non-volatile storage for NMS-assigned asset
            identifiers.

            Write access is not required for physical entities which are
            permanently contained within another physical entity."
    ::= { entityCompliances 2 }






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-- MIB groupings

entityPhysicalGroup    OBJECT-GROUP
    OBJECTS {
              entPhysicalDescr,
              entPhysicalVendorType,
              entPhysicalContainedIn,
              entPhysicalClass,
              entPhysicalParentRelPos,
              entPhysicalName
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects which are 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,
              entLogicalContextEngineID,
              entLogicalContextName
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects which are 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 which are used to represent the
            associations between multiple logical entities, physical





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            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 which are 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
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects which are used to represent
            physical system components, for which a single agent
            provides management information.  These objects are
            mandatory for agents conforming to version 2 of the Entity
            MIB."
    ::= { entityGroups 6 }

entityLogical2Group    OBJECT-GROUP
    OBJECTS {





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              entLogicalContextEngineID,
              entLogicalContextName
            }
    STATUS  current
    DESCRIPTION
            "The collection of objects which are used to represent the
            list of logical entities for which a single agent provides
            management information.  These objects are mandatory for
            agents conforming to version 2 of the Entity MIB."
    ::= { entityGroups 7 }

END






































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6.  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.


6.1.  Router/Bridge

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'

    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'

      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'

    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)





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      entPhysicalParentRelPos.4 ==      1
      entPhysicalName.4 ==              'M1'

      entPhysicalDescr.5 ==             "Acme Ethernet-100 Port Rev G"
      entPhysicalVendorType.5  ==       acmeProducts.portTypes.2
      entPhysicalContainedIn.5 ==       4
      entPhysicalClass.5 ==             port(10)
      entPhysicalParentRelPos.5 ==      1
      entPhysicalName.5 ==              'P1'

      entPhysicalDescr.6 ==             "Acme Ethernet-100 Port Rev G"
      entPhysicalVendorType.6  ==       acmeProducts.portTypes.2
      entPhysicalContainedIn.6 ==       4
      entPhysicalClass.6 ==             port(10)
      entPhysicalParentRelPos.6 ==      2
      entPhysicalName.6 ==              'P2'

      entPhysicalDescr.7 ==             "Acme Router-100 F-Port: Rev B"
      entPhysicalVendorType.7  ==       acmeProducts.portTypes.3
      entPhysicalContainedIn.7 ==       4
      entPhysicalClass.7 ==             port(10)
      entPhysicalParentRelPos.7 ==      3
      entPhysicalName.7 ==              'P3'

   Slot 2 contains another 3-port module:
      entPhysicalDescr.8 ==             "Acme Router-100 Comm Module: Rev C"
      entPhysicalVendorType.8  ==       acmeProducts.moduleTypes.15
      entPhysicalContainedIn.8 ==       3
      entPhysicalClass.8 ==             module(9)
      entPhysicalParentRelPos.8 ==      1
      entPhysicalName.8 ==              'M2'

      entPhysicalDescr.9 ==             "Acme Fddi-100 Port Rev CC"
      entPhysicalVendorType.9 ==        acmeProducts.portTypes.5
      entPhysicalContainedIn.9 ==       8
      entPhysicalClass.9 ==             port(10)
      entPhysicalParentRelPos.9 ==      1
      entPhysicalName.9 ==              'FDDI Primary'

      entPhysicalDescr.10 ==            "Acme Ethernet-100 Port Rev G"
      entPhysicalVendorType.10 ==       acmeProducts.portTypes.2
      entPhysicalContainedIn.10 ==      8
      entPhysicalClass.10 ==            port(10)
      entPhysicalParentRelPos.10 ==     2
      entPhysicalName.10 ==             'Ethernet A'





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      entPhysicalDescr.11 ==            "Acme Ethernet-100 Port Rev G"
      entPhysicalVendorType.11 ==       acmeProducts.portTypes.2
      entPhysicalContainedIn.11 ==      8
      entPhysicalClass.11 ==            port(10)
      entPhysicalParentRelPos.11 ==     3
      entPhysicalName.11 ==             'Ethernet B'

   Logical entities -- entLogicalTable
    2 OSPF instances:
      entLogicalDescr.1 ==            "Acme OSPF v1.1"
      entLogicalType.1 ==             ospf
      entLogicalCommunity.1 ==        "public-ospf1"
      entLogicalTAddress.1 ==         124.125.126.127:161
      entLogicalTDomain.1 ==          snmpUDPDomain

      entLogicalDescr.2 ==            "Acme OSPF v1.1"
      entLogicalType.2 ==             ospf
      entLogicalCommunity.2 ==        "public-ospf2"
      entLogicalTAddress.2 ==         124.125.126.127:161
      entLogicalTDomain.2 ==          snmpUDPDomain

    2 logical bridges:
      entLogicalDescr.3 ==            "Acme Bridge v2.1.1"
      entLogicalType.3  ==            dod1dBridge
      entLogicalCommunity.3 ==        "public-bridge1"
      entLogicalTAddress.3 ==         124.125.126.127:161
      entLogicalTDomain.3 ==          snmpUDPDomain

      entLogicalDescr.4 ==            "Acme Bridge v2.1.1"
      entLogicalType.4 ==             dod1dBridge
      entLogicalCommunity.4 ==        "public-bridge2"
      entLogicalTAddress.4 ==         124.125.126.127:161
      entLogicalTDomain.4 ==          snmpUDPDomain

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

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

  1st bridge group: uses module 1, all ports

  [ed. -- Note that these mappings are included in the table since
  another logical entity (1st OSPF) utilizes one of the





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  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
      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.9.3   ==        ifIndex.204
      entAliasMappingIdentifier.10.0  ==        ifIndex.5
      entAliasMappingIdentifier.10.3  ==        ifIndex.205
      entAliasMappingIdentifier.11.0  ==        ifIndex.6
      entAliasMappingIdentifier.11.3  ==        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





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  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.1.11 = 11


6.2.  Repeaters

A 3-slot Hub with 2 backplane ethernet segments.  Slot three is empty,
and the remaining slots contain ethernet repeater modules. [ed. -- Note
that a replacement for the current Repeater MIB (RFC 1516) is likely to
emerge soon, and it will no longer be necessary to access repeater MIB
data in different naming scopes.]

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'

   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'

      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'

   3 slots within the chassis:
      entPhysicalDescr.4 ==          "Acme Hub Slot Type RB"





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      entPhysicalVendorType.4  ==    acmeProducts.slotTypes.5
      entPhysicalContainedIn.4 ==    1
      entPhysicalClass.4 ==          container(5)
      entPhysicalParentRelPos.4 ==   1
      entPhysicalName.4 ==           'Slot 1'

      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'

      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'

   Slot 1 contains a plug-in module with 4 10-BaseT ports:
      entPhysicalDescr.7  ==         "Acme 10Base-T Module 114 Rev A"
      entPhysicalVendorType.7   ==   acmeProducts.moduleTypes.32
      entPhysicalContainedIn.7  ==   4
      entPhysicalClass.7 ==          module(9)
      entPhysicalParentRelPos.7 ==   1
      entPhysicalName.7 ==           'M1'

      entPhysicalDescr.8  ==         "Acme 10Base-T Port RB Rev A"
      entPhysicalVendorType.8   ==   acmeProducts.portTypes.10
      entPhysicalContainedIn.8  ==   7
      entPhysicalClass.8 ==          port(10)
      entPhysicalParentRelPos.8 ==   1
      entPhysicalName.8 ==           'Ethernet-A'

      entPhysicalDescr.9  ==         "Acme 10Base-T Port RB Rev A"
      entPhysicalVendorType.9   ==   acmeProducts.portTypes.10
      entPhysicalContainedIn.9  ==   7
      entPhysicalClass.9 ==          port(10)
      entPhysicalParentRelPos.9 ==   2
      entPhysicalName.9 ==           'Ethernet-B'

      entPhysicalDescr.10 ==         "Acme 10Base-T Port RB Rev B"
      entPhysicalVendorType.10  ==   acmeProducts.portTypes.10
      entPhysicalContainedIn.10 ==   7





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      entPhysicalClass.10 ==         port(10)
      entPhysicalParentRelPos.10 ==  3
      entPhysicalName.10 ==          'Ethernet-C'

      entPhysicalDescr.11 ==         "Acme 10Base-T Port RB Rev B"
      entPhysicalVendorType.11  ==   acmeProducts.portTypes.10
      entPhysicalContainedIn.11 ==   7
      entPhysicalClass.11 ==         port(10)
      entPhysicalParentRelPos.11 ==  4
      entPhysicalName.11 ==          'Ethernet-D'

   Slot 2 contains another ethernet module with 2 ports.
      entPhysicalDescr.12 ==         "Acme 10Base-T Module Model 4 Rev A"
      entPhysicalVendorType.12 ==    acmeProducts.moduleTypes.30
      entPhysicalContainedIn.12 =    5
      entPhysicalClass.12 ==         module(9)
      entPhysicalParentRelPos.12 ==  1
      entPhysicalName.12 ==          'M2'

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

      entPhysicalDescr.14 ==         "Acme 10Base-T Port RD Rev B"
      entPhysicalVendorType.14  ==   acmeProducts.portTypes.14
      entPhysicalContainedIn.14 ==   12
      entPhysicalClass.14 ==         port(10)
      entPhysicalParentRelPos.14 ==  2
      entPhysicalName.14 ==          'E2'

Logical entities -- entLogicalTable
   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 ==      124.125.126.127:161
      entLogicalTDomain.1 ==       snmpUDPDomain

   Repeater 2--comprised of any ports attached to backplane 2:
      entLogicalDescr.2 ==         "Acme repeater v3.1"
      entLogicalType.2  ==         snmpDot3RptrMgt
      entLogicalCommunity.2 ==     "public-repeater2"





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      entLogicalTAddress.2 ==      124.125.126.127:161
      entLogicalTDomain.2 ==       snmpUDPDomain

Logical to Physical Mappings -- entLPMappingTable:

  repeater1 uses backplane 1, slot 1-ports 1 & 2, slot 2-port 1
  [ed. -- Note that a mapping to the module is not included,
   since in 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





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  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





































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7.  Acknowledgements

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



8.  References

[1]  Harrington, D., Presuhn, R., and B. Wijnen, "An Architecture for
     Describing SNMP Management Frameworks", RFC 2271, Cabletron
     Systems, Inc., BMC Software, Inc., IBM T. J. Watson Research,
     January 1998

[2]  Rose, M., and K. McCloghrie, "Structure and Identification of
     Management Information for TCP/IP-based Internets", RFC 1155,
     Performance Systems International, Hughes LAN Systems, May 1990

[3]  Rose, M., and K. McCloghrie, "Concise MIB Definitions", RFC 1212,
     Performance Systems International, Hughes LAN Systems, March 1991

[4]  M. Rose, "A Convention for Defining Traps for use with the SNMP",
     RFC 1215, Performance Systems International, March 1991

[5]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S.
     Waldbusser, "Structure of Management Information for Version 2 of
     the Simple Network Management Protocol (SNMPv2)", RFC 1902, SNMP
     Research,Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc.,
     International Network Services, January 1996.

[6]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S.
     Waldbusser, "Textual Conventions for Version 2 of the Simple
     Network Management Protocol (SNMPv2)", RFC 1903, SNMP Research,
     Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc.,
     International Network Services, January 1996.

[7]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S.
     Waldbusser, "Conformance Statements for Version 2 of the Simple
     Network Management Protocol (SNMPv2)", RFC 1904, SNMP Research,
     Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc.,
     International Network Services, January 1996.

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





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[9]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S.
     Waldbusser, "Introduction to Community-based SNMPv2", RFC 1901,
     SNMP Research, Inc., Cisco Systems, Inc., Dover Beach Consulting,
     Inc., International Network Services, January 1996.

[10] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S.
     Waldbusser, "Transport Mappings for Version 2 of the Simple Network
     Management Protocol (SNMPv2)", RFC 1906, SNMP Research, Inc., Cisco
     Systems, Inc., Dover Beach Consulting, Inc., International Network
     Services, January 1996.

[11] Case, J., Harrington D., Presuhn R., and B. Wijnen, "Message
     Processing and Dispatching for the Simple Network Management
     Protocol (SNMP)", RFC 2272, SNMP Research, Inc., Cabletron Systems,
     Inc., BMC Software, Inc., IBM T. J. Watson Research, January 1998.

[12] Blumenthal, U., and B. Wijnen, "User-based Security Model (USM) for
     version 3 of the Simple Network Management Protocol (SNMPv3)", RFC
     2274, IBM T. J. Watson Research, January 1998.

[13] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S.
     Waldbusser, "Protocol Operations for Version 2 of the Simple
     Network Management Protocol (SNMPv2)", RFC 1905, SNMP Research,
     Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc.,
     International Network Services, January 1996.

[14] Levi, D., Meyer, P., and B. Stewart, MPv3 Applications", RFC 2273,
     SNMP Research, Inc., Secure Computing Corporation, Cisco Systems,
     January 1998.

[15] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based Access
     Control Model (VACM) for the Simple Network Management Protocol
     (SNMP)", RFC 2275, IBM T. J. Watson Research, BMC Software, Inc.,
     Cisco Systems, Inc., January 1998.

[16] McCloghrie, K., Bierman, A., "Entity MIB using SMIv2", RFC 2037,
     Cisco Systems, October 1996.

[17] McCloghrie, K., Kastenholz, F., "The Interfaces Group MIB Using
     SMIv2", RFC 2233, Cisco Systems, FTP Software, November, 1997.










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9.  Security Considerations

In order to implement this MIB, an agent must make certain management
information available about various logical and physical entities within
a managed system, which may be considered sensitive in some network
environments.

Therefore, a network administrator may wish to employ instance-level
access control, and configure the Entity MIB access (e.g., community
strings in SNMPv1 and SNMPv2C), such that certain instances within this
MIB (e.g., entLogicalCommunity, or entire entLogicalEntries,
entPhysicalEntries, and associated mapping table entries), are excluded
from particular MIB views. SNMPv3 agents may also wish to employ
instance-level access control, in order to exclude certain instances
within this MIB (e.g., entLogicalContextEngineID and
entLogicalContextName) from particular MIB views.


10.  Authors' Addresses

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

     Andy Bierman
     Cisco Systems, Inc.
     170 West Tasman Drive
     San Jose, CA 95134
     Phone: 408-527-3711
     Email: abierman@cisco.com

















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11.  Full Copyright Statement

Copyright (C) The Internet Society (1998).  All Rights Reserved.

This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it or
assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are included
on all such copies and derivative works.  However, this document itself
may not be modified in any way, such as by removing the copyright notice
or references to the Internet Society or other Internet organizations,
except as needed for the purpose of developing Internet standards in
which case the procedures for copyrights defined in the Internet
Standards process must be followed, or as required to translate it into
languages other than English.

The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on an "AS
IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK
FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE."
























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Table of Contents


1 Copyright Notice ................................................    1
2 Abstract ........................................................    2
3 The SNMP Network Management Framework ...........................    2
4 Overview ........................................................    3
4.1 Terms .........................................................    4
4.2 Relationship to Community Strings .............................    5
4.3 Relationship to SNMP Contexts .................................    5
4.4 Relationship to Proxy Mechanisms ..............................    6
4.5 Relationship to a Chassis MIB .................................    6
4.6 Relationship to the Interfaces MIB ............................    6
4.7 Relationship to the Other MIBs ................................    7
4.8 Relationship to Naming Scopes .................................    7
4.9 Multiple Instances of the Entity MIB ..........................    7
4.10 Re-Configuration of Entities .................................    8
4.11 MIB Structure ................................................    8
4.11.1 entityPhysical Group .......................................    9
4.11.2 entityLogical Group ........................................   10
4.11.3 entityMapping Group ........................................   10
4.11.4 entityGeneral Group ........................................   10
4.11.5 entityNotifications Group ..................................   11
4.12 Multiple Agents ..............................................   11
4.13 Change Log ...................................................   11
4.13.1 Version 00 .................................................   11
5 Definitions .....................................................   12
6 Usage Examples ..................................................   40
6.1 Router/Bridge .................................................   40
6.2 Repeaters .....................................................   44
7 Acknowledgements ................................................   49
8 References ......................................................   49
9 Security Considerations .........................................   51
10 Authors' Addresses .............................................   51
11 Full Copyright Statement .......................................   52















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