Network Working Group                                         A. Bierman
Request for Comments: 2922                           Cisco Systems, Inc.
Category: Informational                                         K. Jones
                                                        Nortel Networks
                                                         September 2000


                        Physical Topology MIB

Status of this Memo

  This memo provides information for the Internet community.  It does
  not specify an Internet standard of any kind.  Distribution of this
  memo is unlimited.

Copyright Notice

  Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

  This memo defines a portion of the Management Information Base (MIB)
  for use with network management protocols in the Internet community.
  In particular, it describes managed objects used for managing
  physical topology identification and discovery.

Table of Contents

  1 The SNMP Network Management Framework ............................2
  2 Overview .........................................................3
  2.1 Terms ..........................................................3
  2.2 Design Goals ...................................................5
  3 Topology Framework ...............................................6
  3.1 Devices and Topology Agents ....................................6
  3.2 Topology Mechanisms ............................................7
  3.3 Future Considerations ..........................................7
  4 Physical Topology MIB ............................................7
  4.1 Persistent Identifiers .........................................8
  4.2 Relationship to Entity MIB .....................................8
  4.3 Relationship to Interfaces MIB .................................9
  4.4 Relationship to RMON-2 MIB .....................................9
  4.5 Relationship to Bridge MIB .....................................9
  4.6 Relationship to Repeater MIB ...................................9
  4.7 MIB Structure .................................................10
  4.7.1 ptopoData Group .............................................10
  4.7.2 ptopoGeneral Group ..........................................10
  4.7.3 ptopoConfig Group ...........................................10
  4.8 Physical Topology MIB Definitions .............................10



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  5 Intellectual Property ...........................................27
  6 Acknowledgements ................................................28
  7 References ......................................................28
  8 Security Considerations .........................................30
  9 Authors' Addresses ..............................................31
  10 Full Copyright Statement .......................................32

1.  The SNMP Network Management Framework

  The SNMP Management Framework presently consists of five major
  components:

       o   An overall architecture, described in RFC 2571 [RFC2571].

       o   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 STD 16, RFC 1155 [RFC1155], STD 16, RFC
           1212 [RFC1212] and RFC 1215 [RFC1215].  The second version,
           called SMIv2, is described in STD 58, RFC 2578 [RFC2578],
           STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580 [RFC2580].

       o   Message protocols for transferring management information.
           The first version of the SNMP message protocol is called
           SNMPv1 and described in STD 15, RFC 1157 [RFC1157].  A
           second version of the SNMP message protocol, which is not an
           Internet standards track protocol, is called SNMPv2c and
           described in RFC 1901 [RFC1901] and RFC 1906 [RFC1906].  The
           third version of the message protocol is called SNMPv3 and
           described in RFC 1906 [RFC1906], RFC 2572 [RFC2572] and RFC
           2574 [RFC2574].

       o   Protocol operations for accessing management information.
           The first set of protocol operations and associated PDU
           formats is described in STD 15, RFC 1157 [RFC1157].  A
           second set of protocol operations and associated PDU formats
           is described in RFC 1905 [RFC1905].

       o   A set of fundamental applications described in RFC 2573
           [RFC2573] and the view-based access control mechanism
           described in RFC 2575 [RFC2575].

  A more detailed introduction to the current SNMP Management Framework
  can be found in RFC 2570 [RFC2570].

  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.



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  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
  equivalent, except where objects or events are omitted because no
  translation is possible (use of Counter64).  Some machine readable
  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.

2.  Overview

  There is a need for a standardized means of representing the physical
  network connections pertaining to a given management domain.  The
  Physical Topology MIB (PTOPO-MIB) provides a standard way to identify
  connections between network ports and to discover network addresses
  of SNMP agents containing management information associated with each
  port.

  A topology mechanism is used to discover the information required by
  the PTOPO-MIB.  There is a need for a standardized topology mechanism
  to increase the likelihood of multi-vendor interoperability of such
  physical topology management information.  The PTOPO-MIB does not,
  however, specify or restrict the discovery mechanism(s) used for an
  implementation of the PTOPO-MIB.  Topology mechanisms exist for
  certain media types (such as FDDI) and proprietary mechanisms exist
  for other media such as shared media Ethernet, switched Ethernet, and
  Token Ring.  Rather than specifying mechanisms for each type of
  technology, the PTOPO-MIB allows co-existence of multiple topology
  mechanisms.  The required objects of the PTOPO-MIB define the core
  requirements for any topology mechanism.

  The scope of the physical topology (PTOPO) mechanism is the
  identification of connections between two network ports.  Network
  addresses of SNMP agents containing management information associated
  with each port can also be identified.

2.1.  Terms

  Some terms are used throughout this document:

  Physical Topology
        Physical topology represents the topology model for layer 1 of
        the OSI stack - the physical layer.  Physical topology consists
        of identifying the devices on the network and how they are
        physically interconnected.  By definition of this document,
        physical topology does not imply a physical relationship
        between ports on the same device.  Other means exist for



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        determining these relationships (e.g., Entity MIB [RFC2737])
        exist for determining these relationships.  Note that physical
        topology is independent of logical topology, which associates
        ports based on higher layer attributes, such as network layer
        address.

  Chassis
        A chassis is a physical component which contains other physical
        components.  It is identified by an entPhysicalEntry with an
        entPhysicalClass value of 'chassis(3)' and an
        entPhysicalContainedIn value of zero.  A chassis identifier
        consists of a globally unique SnmpAdminString.

  Local Chassis
        The particular chassis containing the SNMP agent implementing
        the PTOPO MIB.

  Port
        A port is a physical component which can be connected to
        another port through some medium.  It is identified by an
        entPhysicalEntry with an entPhysicalClass value of 'port(10)'.
        A port identifier consists of an SnmpAdminString which must be
        unique within the context of the chassis which contains the
        port.

  Connection Endpoint
        A connection endpoint consists of a physical port, which is
        contained within a single physical chassis.

  Connection Endpoint Identifier
        A connection endpoint is identified by a globally unique
        chassis identifier and a port identifier unique within the
        associated chassis.

  Connection
        A connection consists of two physical ports, and the attached
        physical medium, configured for the purpose of transferring
        network traffic between the ports.  A connection is identified
        by its endpoint identifiers.

  Non-local Connection
        A connection for which neither endpoint is located on the local
        chassis.








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  Cloud
        A cloud identifies a portion of the topology for which
        insufficient information is known to completely infer the
        interconnection of devices that make up that portion of the
        topology.


2.2.  Design Goals

  Several factors influenced the design of this physical topology
  function:

      - Simplicity
        The physical topology discovery function should be as simple as
        possible, exposing only the information needed to identify
        connection endpoints and the SNMP agent(s) associated with each
        connection endpoint.

      - Completeness
        At least one standard discovery protocol capable of supporting
        the standard physical topology MIB must be defined.  Multi-
        vendor interoperability will not be achievable unless a simple
        and extensible discovery protocol is available.  However, the
        PTOPO MIB should not specify or restrict the topology discovery
        mechanisms an agent can use.

      - No Functional Overlap
        Existing standard MIBs should be utilized whenever possible.
        Physical topology information is tightly coupled to
        functionality found in the Interfaces MIB [RFC2233] and Entity
        MIB [RFC2737].  New physical topology MIB objects should not
        duplicate these MIBs.

      - Identifier Stability
        Connection endpoint identifiers must be persistent (i.e. stable
        across device reboots).  Dynamic primary key objects like
        ifIndex and entPhysicalIndex are not suitable for table indices
        in a physical topology MIB that is replicated and distributed
        throughout a managed system.

      - Identifier Flexibility
        Persistent string-based component identifiers should be
        supported from many sources.  Chassis identifiers may be found
        in the Entity MIB [RFC2737], and port identifiers may be found
        in the Interfaces MIB [RFC2233] or Entity MIB [RFC2737].






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      - Partial Topology Support
        Physical topology data for remote components may only be
        partially available to an agent.  An enumerated INTEGER
        hierarchy of component identifier types allows for incomplete
        physical connection identifier information to be substituted
        with secondary information such as unicast source MAC address
        or network address associated with a particular port.  A PTOPO
        Agent maintains information derived from the 'best' source of
        information for each connection.  If a 'better' identifier
        source is detected, the PTOPO entries are updated accordingly.
        It is an implementation specific matter whether a PTOPO agent
        replaces 'old' entries or retains them, however an agent must
        remove information known to be incorrect.

      - Low Polling Impact
        Physical topology polling should be minimized through
        techniques such as TimeFiltered data tables (from RMON-2
        [RFC2021]), and last-change notifications.

3.  Topology Framework

  This section describes the physical topology framework in detail.

3.1.  Devices and Topology Agents

  The network devices, along with their physical connectivity, make up
  the physical topology.  Some of these devices (but maybe not all)
  provide management agents that report their local physical topology
  information to a manager via the physical topology MIB.

  These devices include communication infrastructure devices, such as
  hubs, switches, and routers, as well as 'leaf' devices such as
  workstations, printers, and servers.  Generally, user data passes
  through infrastructure devices while leaf devices are sources and
  sinks of data.  Both types of devices may implement the physical
  topology MIB, although implementation within leaf devices is much
  less critical.

  Each managed device collects physical topology information from the
  network, based on the topology mechanism(s) it is configured to use.
  The data represents this agent's local view of the physical network.
  Part of the topology data collected must include the identification
  of other local agents which may contain additional topology
  information.  The definition of 'local' varies based on the topology
  mechanism or mechanisms being used.






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3.2.  Topology Mechanisms

  A topology mechanism is a means, possibly requiring some sort of
  protocol, by which devices determine topology information.  The
  topology mechanism must provide sufficient information to populate
  the MIB described later in this document.

  Topology mechanisms can be active or passive.  Active mechanisms
  require a device to send and receive topology protocol packets.
  These packets provide the device ID of the source of the packet and
  may also indicate out which port the packet was transmitted.  When
  receiving these packets, devices typically are required to identify
  on which port that packet was received.

  Passive mechanisms take advantage of data on the network to populate
  the topology MIB.  By maintaining a list of device identifiers seen
  on each port of all devices in a network, it is possible to populate
  the PTOPO-MIB.

  Many instances of a particular topology mechanism may be in use on a
  given network, and many different mechanisms may be employed.  In
  some cases, multiple mechanisms may overlap across part of the
  physical topology with individual ports supporting more than one
  topology mechanism.  In general, this simply allows the port to
  collect more robust topology information.  Agents may need to be
  configured so that they know which mechanism(s) are in use on any
  given portion of the network.

  Most topology mechanisms need to be bounded to a subset of the
  network to contain their impact on the network and limit the size of
  topology tables maintained by the agent.  Topology mechanisms are
  often naturally bounded by the media on which they run (e.g. FDDI
  topology mechanism) or by routers in the network that intentionally
  block the mechanism from crossing into other parts of the network.

3.3.  Future Considerations

  While the framework presented here is focused on physical topology,
  it may well be that the topology mechanisms and MIB described could
  be extended to include logical topology information as well.  That is
  not a focus of this memo.

4.  Physical Topology MIB

  This section describes and defines the Physical Topology MIB.






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4.1.  Persistent Identifiers

  The PTOPO MIB utilizes non-volatile identifiers to distinguish
  individual chassis and port components.  These identifiers are
  associated with external objects in order to relate topology
  information to the existing managed objects.

  In particular, an object from the Entity MIB [RFC2737] or Interfaces
  MIB [RFC2233] can be used as the 'reference-point' for a connection
  component identifier.

  The Physical Topology MIB uses two identifier types pertaining to the
  PTOPO MIB:

      - globally unique chassis identifiers.

      - port identifiers; unique only within the chassis which contains
        the port.

  Identifiers are stored as OCTET STRINGs, which are limited to 32
  bytes in length, This supports flexible naming conventions and
  constrains the non-volatile storage requirements for an agent.

4.2.  Relationship to Entity MIB

  The first version of the Entity MIB [RFC2037] allows the physical
  component inventory and hierarchy to be identified.  However, this
  MIB does not provide persistent component identifiers, which are
  required for the PTOPO MIB.  Therefore, version 2 of the Entity MIB
  [RFC2737] is required to support that feature.  Specifically, the
  entPhysicalAlias object is utilized as a persistent chassis
  identifier.

  For agents implementing the PTOPO MIB, this new object must be used
  to represent the chassis identifier.  Port identifiers can be based
  on the entPhysicalAlias object associated with the port, but only if
  the port is not represented as an interface in the ifXTable.

  Implementation of the entPhysicalGroup [RFC2737] and the
  entPhysicalAlias object [RFC2737] are mandatory for SNMP agents which
  implement the PTOPO MIB.  No other objects must be implemented from
  these MIBs to support the physical topology function.









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4.3.  Relationship to Interfaces MIB

  The PTOPO MIB requires a persistent identifier for each port.  The
  Interfaces MIB [RFC2233] provides a standard mechanism for managing
  network interfaces.  Unfortunately, not all ports which may be
  represented in the PTOPO MIB are also represented in the Interfaces
  MIB (e.g., repeater ports).

  For agents which implement the PTOPO MIB, for each port also
  represented in the Interfaces MIB, the agent must use the associated
  ifAlias value for the port identifier.  For each port not represented
  in the Interfaces MIB, the associated entPhysicalAlias value must be
  used for the port identifier.  Note that the PTOPO MIB requires only
  minimal support from the Interfaces MIB.  Specifically, the '
  ifGeneralInformationGroup' level of conformance must be provided for
  each port also identified in the PTOPO MIB.  The agent may choose to
  support these objects with read-only access, as specified in the
  conformance section of the Interfaces MIB.

4.4.  Relationship to RMON-2 MIB

  The RMON-2 MIB [RFC2021] contains address mapping information which
  can be integrated with physical topology information.  The physical
  ports identified in a physical topology MIB can be related to the MAC
  and network layer addresses found in the addressMapTable.

4.5.  Relationship to Bridge MIB

  The Bridge MIB [RFC1493] contains information which may relate to
  physical ports represented in the ptopoConnTable.  Entries in the
  dot1dBasePortTable and dot1dStpPortTable can by related to physical
  ports represented in the PTOPO MIB.  Also, bridge port MAC addresses
  may be used as chassis and port identifiers in some situations.

4.6.  Relationship to Repeater MIB

  The Repeater MIB [RFC2108] contains information which may relate to
  physical ports represented in the PTOPO MIB.  Entries in the
  rptrPortTable and rptrMonitorPortTable can by related to physical
  ports represented in the ptopoConnTable.  Entries in the
  rptrInfoTable and rptrMonTable can be related to repeater backplanes
  possibly represented in the ptopoConnTable.









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4.7.  MIB Structure

  The PTOPO MIB contains three MIB object groups:

      - ptopoData
        Exposes physical topology data learned from discovery protocols
        and/or manual configuration.

      - ptopoGeneral
        Contains general information regarding PTOPO MIB status.

      - ptopoConfig
        Contains configuration variables for the PTOPO MIB agent
        function.

4.7.1.  ptopoData Group

  This group contains a single table to identity physical topology
  data.

  The ptopoConnTable contains information about the connections learned
  or configured on behalf of the PTOPO MIB SNMP Agent.

4.7.2.  ptopoGeneral Group

  This group contains some scalar objects to report the status of the
  PTOPO MIB information currently known to the SNMP Agent.  The global
  last change time, and table add and delete counters allow an NMS to
  set threshold alarms to trigger PTOPO polling.

4.7.3.  ptopoConfig Group

  This group contains tables to configure the behavior of the physical
  topology function.  The transmission of ptopoLastChange notifications
  can be configured using the ptopoConfigTrapInterval scalar MIB
  object.

4.8.  Physical Topology MIB Definitions

PTOPO-MIB DEFINITIONS ::= BEGIN

IMPORTS
   MODULE-IDENTITY, OBJECT-TYPE, NOTIFICATION-TYPE,
   Integer32, Counter32, mib-2
       FROM SNMPv2-SMI
   TEXTUAL-CONVENTION, AutonomousType, RowStatus, TimeStamp, TruthValue
       FROM SNMPv2-TC
   MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP



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       FROM SNMPv2-CONF
   TimeFilter
       FROM RMON2-MIB
   PhysicalIndex
       FROM ENTITY-MIB
   AddressFamilyNumbers
       FROM IANA-ADDRESS-FAMILY-NUMBERS-MIB;

ptopoMIB MODULE-IDENTITY
   LAST-UPDATED "200009210000Z"
   ORGANIZATION "IETF; PTOPOMIB Working Group"
   CONTACT-INFO
      "PTOPOMIB WG Discussion:
       [email protected]
       Subscription:
       [email protected]
         msg body: [un]subscribe ptopomib

       Andy Bierman
       Cisco Systems Inc.
       170 West Tasman Drive
       San Jose, CA 95134
       408-527-3711
       [email protected]

       Kendall S. Jones
       Nortel Networks
       4401 Great America Parkway
       Santa Clara, CA 95054
       408-495-7356
       [email protected]"
   DESCRIPTION
           "The MIB module for physical topology information."
   REVISION        "200009210000Z"
   DESCRIPTION
           "Initial Version of the Physical Topology MIB.  This version
           published as RFC 2922."
   ::= { mib-2 79 }

ptopoMIBObjects   OBJECT IDENTIFIER ::= { ptopoMIB 1 }


-- MIB groups
ptopoData         OBJECT IDENTIFIER ::= { ptopoMIBObjects 1 }
ptopoGeneral      OBJECT IDENTIFIER ::= { ptopoMIBObjects 2 }
ptopoConfig       OBJECT IDENTIFIER ::= { ptopoMIBObjects 3 }

-- textual conventions



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PtopoGenAddr ::= TEXTUAL-CONVENTION
   STATUS      current
   DESCRIPTION
           "The value of an address."
   SYNTAX      OCTET STRING (SIZE (0..20))

PtopoChassisIdType ::= TEXTUAL-CONVENTION
   STATUS      current
   DESCRIPTION
           "This TC describes the source of a chassis identifier.

           The enumeration 'chasIdEntPhysicalAlias(1)' represents a
           chassis identifier based on the value of entPhysicalAlias
           for a chassis component (i.e., an entPhysicalClass value of
           'chassis(3)').

           The enumeration 'chasIdIfAlias(2)' represents a chassis
           identifier based on the value of ifAlias for an interface
           on the containing chassis.

           The enumeration 'chasIdPortEntPhysicalAlias(3)' represents
           a chassis identifier based on the value of entPhysicalAlias
           for a port or backplane component (i.e., entPhysicalClass
           value of 'port(10)' or 'backplane(4)'), within the
           containing chassis.

           The enumeration 'chasIdMacAddress(4)' represents a chassis
           identifier based on the value of a unicast source MAC
           address (encoded in network byte order and IEEE 802.3
           canonical bit order), of a port on the containing chassis.

           The enumeration 'chasIdPtopoGenAddr(5)' represents a
           chassis identifier based on a network address, associated
           with a particular chassis.  The encoded address is actually
           composed of two fields.  The first field is a single octet,
           representing the IANA AddressFamilyNumbers value for the
           specific address type, and the second field is the
           PtopoGenAddr address value."
   SYNTAX      INTEGER {
           chasIdEntPhysicalAlias(1),
           chasIdIfAlias(2),
           chasIdPortEntPhysicalAlias(3),
           chasIdMacAddress(4),
           chasIdPtopoGenAddr(5)
   }

PtopoChassisId ::= TEXTUAL-CONVENTION
   STATUS      current



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   DESCRIPTION
           "This TC describes the format of a chassis identifier
           string.  Objects of this type are always used with an
           associated PtopoChassisIdType object, which identifies the
           format of the particular PtopoChassisId object instance.

           If the associated PtopoChassisIdType object has a value of
           'chasIdEntPhysicalAlias(1)', then the octet string
           identifies a particular instance of the entPhysicalAlias
           object for a chassis component (i.e., an entPhysicalClass
           value of 'chassis(3)').

           If the associated PtopoChassisIdType object has a value of
           'chasIdIfAlias(2)', then the octet string identifies a
           particular instance of the ifAlias object for an interface
           on the containing chassis.

           If the associated PtopoChassisIdType object has a value of
           'chasIdPortEntPhysicalAlias(3)', then the octet string
           identifies a particular instance of the entPhysicalAlias
           object for a port or backplane component within the
           containing chassis.

           If the associated PtopoChassisIdType object has a value of
           'chasIdMacAddress(4)', then this string identifies a
           particular unicast source MAC address (encoded in network
           byte order and IEEE 802.3 canonical bit order), of a port on
           the containing chassis.

           If the associated PtopoChassisIdType object has a value of
           'chasIdPtopoGenAddr(5)', then this string identifies a
           particular network address, encoded in network byte order,
           associated with one or more ports on the containing chassis.
           The first octet contains the IANA Address Family Numbers
           enumeration value for the specific address type, and octets
           2 through N contain the PtopoGenAddr address value in
           network byte order."
   SYNTAX      OCTET STRING (SIZE (1..32))

PtopoPortIdType ::= TEXTUAL-CONVENTION
   STATUS      current
   DESCRIPTION
           "This TC describes the source of a particular type of port
           identifier used in the PTOPO MIB.

           The enumeration 'portIdIfAlias(1)' represents a port
           identifier based on the ifAlias MIB object.




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RFC 2922                 Physical Topology MIB            September 2000


           The enumeration 'portIdPortEntPhysicalAlias(2)' represents a
           port identifier based on the value of entPhysicalAlias for a
           port or backplane component (i.e., entPhysicalClass value of
           'port(10)' or 'backplane(4)'), within the containing
           chassis.

           The enumeration 'portIdMacAddr(3)' represents a port
           identifier based on a unicast source MAC address, which has
           been detected by the agent and associated with a particular
           port.

           The enumeration 'portIdPtopoGenAddr(4)' represents a port
           identifier based on a network address, detected by the agent
           and associated with a particular port."
   SYNTAX      INTEGER {
           portIdIfAlias(1),
           portIdEntPhysicalAlias(2),
           portIdMacAddr(3),
           portIdPtopoGenAddr(4)
   }

PtopoPortId ::= TEXTUAL-CONVENTION
   STATUS      current
   DESCRIPTION
           "This TC describes the format of a port identifier string.
           Objects of this type are always used with an associated
           PtopoPortIdType object, which identifies the format of the
           particular PtopoPortId object instance.

           If the associated PtopoPortIdType object has a value of
           'portIdIfAlias(1)', then the octet string identifies a
           particular instance of the ifAlias object.

           If the associated PtopoPortIdType object has a value of
           'portIdEntPhysicalAlias(2)', then the octet string
           identifies a particular instance of the entPhysicalAlias
           object for a port component (i.e., entPhysicalClass value of
           'port(10)').

           If the associated PtopoPortIdType object has a value of
           'portIdMacAddr(3)', then this string identifies a particular
           unicast source MAC address associated with the port.

           If the associated PtopoPortIdType object has a value of
           'portIdPtopoGenAddr(4)', then this string identifies a
           network address associated with the port.  The first octet
           contains the IANA AddressFamilyNumbers enumeration value for
           the specific address type, and octets 2 through N contain



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RFC 2922                 Physical Topology MIB            September 2000


           the PtopoGenAddr address value in network byte order."
   SYNTAX      OCTET STRING (SIZE (1..32))


PtopoAddrSeenState ::= TEXTUAL-CONVENTION
   STATUS      current
   DESCRIPTION
           "This TC describes the state of address detection for a
           particular type of port identifier used in the PTOPO MIB.

           The enumeration 'notUsed(1)' represents an entry for which
           the particular MIB object is not applicable to the remote
           connection endpoint,

           The enumeration 'unknown(2)' represents an entry for which
           the particular address collection state is not known.

           The enumeration 'oneAddr(3)'  represents an entry for which
           exactly one source address (of the type indicated by the
           particular MIB object), has been detected.

           The enumeration 'multiAddr(4)'  represents an entry for
           which more than one source address (of the type indicated by
           the particular MIB object), has been detected.

           An agent is expected to set the initial state of the
           PtopoAddrSeenState to 'notUsed(1)' or 'unknown(2)'.

           Note that the PTOPO MIB does not restrict or specify the
           means in which the PtopoAddrSeenState is known to an agent.
           In particular, an agent may detect this information through
           configuration data, or some means other than directly
           monitoring all port traffic."
   SYNTAX      INTEGER {
           notUsed(1),
           unknown(2),
           oneAddr(3),
           multiAddr(4)
   }

--  ***********************************************************
--
--           P T O P O    D A T A     G R O U P
--
--  ***********************************************************

-- Connection Table




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ptopoConnTable OBJECT-TYPE
   SYNTAX      SEQUENCE OF PtopoConnEntry
   MAX-ACCESS  not-accessible
   STATUS      current
   DESCRIPTION
           "This table contains one or more rows per physical network
           connection known to this agent.  The agent may wish to
           ensure that only one ptopoConnEntry is present for each
           local port, or it may choose to maintain multiple
           ptopoConnEntries for the same local port.

           Entries based on lower numbered identifier types are
           preferred over higher numbered identifier types, i.e., lower
           values of the ptopoConnRemoteChassisType and
           ptopoConnRemotePortType objects."
   ::= { ptopoData 1 }

ptopoConnEntry       OBJECT-TYPE
   SYNTAX      PtopoConnEntry
   MAX-ACCESS  not-accessible
   STATUS      current
   DESCRIPTION
           "Information about a particular physical network connection.
           Entries may be created and deleted in this table, either
           manually or by the agent, if a physical topology discovery
           process is active."
   INDEX   {
          ptopoConnTimeMark,
          ptopoConnLocalChassis,
          ptopoConnLocalPort,
          ptopoConnIndex
   }
   ::= { ptopoConnTable 1 }

PtopoConnEntry ::= SEQUENCE {
     ptopoConnTimeMark            TimeFilter,
     ptopoConnLocalChassis        PhysicalIndex,
     ptopoConnLocalPort           PhysicalIndex,
     ptopoConnIndex               Integer32,
     ptopoConnRemoteChassisType   PtopoChassisIdType,
     ptopoConnRemoteChassis       PtopoChassisId,
     ptopoConnRemotePortType      PtopoPortIdType,
     ptopoConnRemotePort          PtopoPortId,
     ptopoConnDiscAlgorithm       AutonomousType,
     ptopoConnAgentNetAddrType    AddressFamilyNumbers,
     ptopoConnAgentNetAddr        PtopoGenAddr,
     ptopoConnMultiMacSASeen      PtopoAddrSeenState,
     ptopoConnMultiNetSASeen      PtopoAddrSeenState,



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     ptopoConnIsStatic            TruthValue,
     ptopoConnLastVerifyTime      TimeStamp,
     ptopoConnRowStatus           RowStatus
}

ptopoConnTimeMark  OBJECT-TYPE
   SYNTAX      TimeFilter
   MAX-ACCESS  not-accessible
   STATUS      current
   DESCRIPTION
           "A TimeFilter for this entry.  See the TimeFilter textual
           convention in RFC 2021 to see how this works."
   ::= { ptopoConnEntry 1 }

ptopoConnLocalChassis  OBJECT-TYPE
   SYNTAX      PhysicalIndex
   MAX-ACCESS  not-accessible
   STATUS      current
   DESCRIPTION
           "The entPhysicalIndex value used to identify the chassis
           component associated with the local connection endpoint."
   ::= { ptopoConnEntry 2 }

ptopoConnLocalPort     OBJECT-TYPE
   SYNTAX      PhysicalIndex
   MAX-ACCESS  not-accessible
   STATUS      current
   DESCRIPTION
           "The entPhysicalIndex value used to identify the port
           component associated with the local connection endpoint."
   ::= { ptopoConnEntry 3 }

ptopoConnIndex    OBJECT-TYPE
   SYNTAX      Integer32  (1..2147483647)
   MAX-ACCESS  not-accessible
   STATUS      current
   DESCRIPTION
           "This object represents an arbitrary local integer value
           used by this agent to identify a particular connection
           instance, unique only for the indicated local connection
           endpoint.

           A particular ptopoConnIndex value may be reused in the event
           an entry is aged out and later re-learned with the same (or
           different) remote chassis and port identifiers.

           An agent is encouraged to assign monotonically increasing
           index values to new entries, starting with one, after each



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RFC 2922                 Physical Topology MIB            September 2000


           reboot.  It is considered unlikely that the ptopoConnIndex
           will wrap between reboots."
   ::= { ptopoConnEntry 4 }

ptopoConnRemoteChassisType  OBJECT-TYPE
   SYNTAX      PtopoChassisIdType
   MAX-ACCESS  read-create
   STATUS      current
   DESCRIPTION
           "The type of encoding used to identify the chassis
           associated with the remote connection endpoint.

           This object may not be modified if the associated
           ptopoConnRowStatus object has a value of active(1)."
   ::= { ptopoConnEntry 5 }

ptopoConnRemoteChassis  OBJECT-TYPE
   SYNTAX      PtopoChassisId
   MAX-ACCESS  read-create
   STATUS      current
   DESCRIPTION
           "The string value used to identify the chassis component
           associated with the remote connection endpoint.

           This object may not be modified if the associated
           ptopoConnRowStatus object has a value of active(1)."
   ::= { ptopoConnEntry 6 }

ptopoConnRemotePortType  OBJECT-TYPE
   SYNTAX      PtopoPortIdType
   MAX-ACCESS  read-create
   STATUS      current
   DESCRIPTION
           "The type of port identifier encoding used in the associated
           'ptopoConnRemotePort' object.

           This object may not be modified if the associated
           ptopoConnRowStatus object has a value of active(1)."
   ::= { ptopoConnEntry 7 }

ptopoConnRemotePort  OBJECT-TYPE
   SYNTAX      PtopoPortId
   MAX-ACCESS  read-create
   STATUS      current
   DESCRIPTION
           "The string value used to identify the port component
           associated with the remote connection endpoint.




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           This object may not be modified if the associated
           ptopoConnRowStatus object has a value of active(1)."
   ::= { ptopoConnEntry 8 }

ptopoConnDiscAlgorithm OBJECT-TYPE
   SYNTAX      AutonomousType
   MAX-ACCESS  read-only
   STATUS      current
   DESCRIPTION
           "An indication of the algorithm used to discover the
           information contained in this conceptual row.

           A value of ptopoDiscoveryLocal indicates this entry was
           configured by the local agent, without use of a discovery
           protocol.

           A value of { 0 0 } indicates this entry was created manually
           by an NMS via the associated RowStatus object. "
   ::= { ptopoConnEntry 9 }

ptopoConnAgentNetAddrType  OBJECT-TYPE
   SYNTAX      AddressFamilyNumbers
   MAX-ACCESS  read-create
   STATUS      current
   DESCRIPTION
           "This network address type of the associated
           ptopoConnNetAddr object, unless that object contains a zero
           length string.  In such a case, an NMS application should
           ignore any returned value for this object.

           This object may not be modified if the associated
           ptopoConnRowStatus object has a value of active(1)."
   ::= { ptopoConnEntry 10 }

ptopoConnAgentNetAddr  OBJECT-TYPE
   SYNTAX      PtopoGenAddr
   MAX-ACCESS  read-create
   STATUS      current
   DESCRIPTION
           "This object identifies a network address which may be used
           to reach an SNMP agent entity containing information for the
           chassis and port components represented by the associated
           'ptopoConnRemoteChassis' and 'ptopoConnRemotePort' objects.
           If no such address is known, then this object shall contain
           an empty string.

           This object may not be modified if the associated
           ptopoConnRowStatus object has a value of active(1)."



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RFC 2922                 Physical Topology MIB            September 2000


   ::= { ptopoConnEntry 11 }

ptopoConnMultiMacSASeen  OBJECT-TYPE
   SYNTAX      PtopoAddrSeenState
   MAX-ACCESS  read-only
   STATUS      current
   DESCRIPTION
           "This object indicates if multiple unicast source MAC
           addresses have been detected by the agent from the remote
           connection endpoint, since the creation of this entry.

           If this entry has an associated ptopoConnRemoteChassisType
           and/or ptopoConnRemotePortType value other than
           'portIdMacAddr(3)', then the value 'notUsed(1)' is returned.

           Otherwise, one of the following conditions must be true:

           If the agent has not yet detected any unicast source MAC
           addresses from the remote port, then the value 'unknown(2)'
           is returned.

           If the agent has detected exactly one unicast source MAC
           address from the remote port, then the value 'oneAddr(3)' is
           returned.

           If the agent has detected more than one unicast source MAC
           address from the remote port, then the value 'multiAddr(4)'
           is returned."
   ::= { ptopoConnEntry 12 }

ptopoConnMultiNetSASeen  OBJECT-TYPE
   SYNTAX      PtopoAddrSeenState
   MAX-ACCESS  read-only
   STATUS      current
   DESCRIPTION
           "This object indicates if multiple network layer source
           addresses have been detected by the agent from the remote
           connection endpoint, since the creation of this entry.

           If this entry has an associated ptopoConnRemoteChassisType
           or ptopoConnRemotePortType value other than
           'portIdGenAddr(4)' then the value 'notUsed(1)' is returned.

           Otherwise, one of the following conditions must be true:

           If the agent has not yet detected any network source
           addresses of the appropriate type from the remote port, then
           the value 'unknown(2)' is returned.



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RFC 2922                 Physical Topology MIB            September 2000


           If the agent has detected exactly one network source address
           of the appropriate type from the remote port, then the value
           'oneAddr(3)' is returned.

           If the agent has detected more than one network source
           address (of the same appropriate type) from the remote port,
           this the value 'multiAddr(4)' is returned."
   ::= { ptopoConnEntry 13 }

ptopoConnIsStatic  OBJECT-TYPE
   SYNTAX      TruthValue
   MAX-ACCESS  read-create
   STATUS      current
   DESCRIPTION
           "This object identifies static ptopoConnEntries.  If this
           object has the value 'true(1)', then this entry is not
           subject to any age-out mechanisms implemented by the agent.

           If this object has the value 'false(2)', then this entry is
           subject to all age-out mechanisms implemented by the agent.

           This object may not be modified if the associated
           ptopoConnRowStatus object has a value of active(1)."
   DEFVAL { false }
   ::= { ptopoConnEntry 14 }

ptopoConnLastVerifyTime  OBJECT-TYPE
   SYNTAX      TimeStamp
   MAX-ACCESS  read-only
   STATUS      current
   DESCRIPTION
           "If the associated value of ptopoConnIsStatic is equal to
           'false(2)', then this object contains the value of sysUpTime
           at the time the conceptual row was last verified by the
           agent, e.g., via reception of a topology protocol message,
           pertaining to the associated remote chassis and port.

           If the associated value of ptopoConnIsStatic is equal to
           'true(1)', then this object shall contain the value of
           sysUpTime at the time this entry was last activated (i.e.,
           ptopoConnRowStatus set to 'active(1)')."
   ::= { ptopoConnEntry 15 }

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



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RFC 2922                 Physical Topology MIB            September 2000


           "The status of this conceptual row."
   ::= { ptopoConnEntry 16 }

--  ***********************************************************
--
--           P T O P O    G E N E R A L     G R O U P
--
--  ***********************************************************

-- last change time stamp for the whole MIB

ptopoLastChangeTime 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 the ptopoConnTable.

           An NMS can use this object to reduce polling of the
           ptopoData group objects."
   ::= { ptopoGeneral 1 }

ptopoConnTabInserts OBJECT-TYPE
   SYNTAX      Counter32
   UNITS       "table entries"
   MAX-ACCESS  read-only
   STATUS      current
   DESCRIPTION
           "The number of times an entry has been inserted into the
           ptopoConnTable."
   ::= { ptopoGeneral 2 }

ptopoConnTabDeletes OBJECT-TYPE
   SYNTAX      Counter32
   UNITS       "table entries"
   MAX-ACCESS  read-only
   STATUS      current

   DESCRIPTION
           "The number of times an entry has been deleted from the
           ptopoConnTable."
   ::= { ptopoGeneral 3 }

ptopoConnTabDrops OBJECT-TYPE
   SYNTAX      Counter32
   UNITS       "table entries"
   MAX-ACCESS  read-only



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   STATUS      current
   DESCRIPTION
           "The number of times an entry would have been added to the
           ptopoConnTable, (e.g., via information learned from a
           topology protocol), but was not because of insufficient
           resources."
   ::= { ptopoGeneral 4 }

ptopoConnTabAgeouts OBJECT-TYPE
   SYNTAX      Counter32
   MAX-ACCESS  read-only
   STATUS      current
   DESCRIPTION
           "The number of times an entry has been deleted from the
           ptopoConnTable because the information timeliness interval
           for that entry has expired."
   ::= { ptopoGeneral 5 }

--  ***********************************************************
--
--           P T O P O    C O N F I G     G R O U P
--
--  ***********************************************************

ptopoConfigTrapInterval OBJECT-TYPE
   SYNTAX      Integer32 (0 | 5..3600)
   UNITS       "seconds"
   MAX-ACCESS  read-write
   STATUS      current
   DESCRIPTION
           "This object controls the transmission of PTOPO
           notifications.

           If this object has a value of zero, then no
           ptopoConfigChange notifications will be transmitted by the
           agent.

           If this object has a non-zero value, then the agent must not
           generate more than one ptopoConfigChange trap-event in the
           indicated period, where a 'trap-event' is the transmission
           of a single notification PDU type to a list of notification
           destinations.  If additional configuration changes occur
           within the indicated throttling period, then these trap-
           events must be suppressed by the agent. An NMS should
           periodically check the value of ptopoLastChangeTime to
           detect any missed ptopoConfigChange trap-events, e.g. due to
           throttling or transmission loss.




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RFC 2922                 Physical Topology MIB            September 2000


           If notification transmission is enabled, the suggested
           default throttling period is 60 seconds, but transmission
           should be disabled by default.

           If the agent is capable of storing non-volatile
           configuration, then the value of this object must be
           restored after a re-initialization of the management
           system."
   DEFVAL { 0 }
   ::= { ptopoConfig 1 }

ptopoConfigMaxHoldTime OBJECT-TYPE
   SYNTAX      Integer32 (1..2147483647)
   UNITS       "seconds"
   MAX-ACCESS  read-write
   STATUS      current
   DESCRIPTION
           "This object specifies the desired time interval for which
           an agent will maintain dynamic ptopoConnEntries.

           After the specified number of seconds since the last time an
           entry was verified, in the absence of new verification
           (e.g., receipt of a topology protocol message), the agent
           shall remove the entry.  Note that entries may not always be
           removed immediately, but may possibly be removed at periodic
           garbage collection intervals.
           This object only affects dynamic ptopoConnEntries, i.e.  for
           which ptopoConnIsStatic equals 'false(2)'. Static entries
           are not aged out.

           Note that dynamic ptopoConnEntries may also be removed by
           the agent due to the expired timeliness of learned topology
           information (e.g., timeliness interval for a remote port
           expires).  The actual age-out interval for a given entry is
           defined by the following formula:

             age-out-time =
               min(ptopoConfigMaxHoldTime, <entry-specific hold-time>)

           where <entry-specific hold-time> is determined by the
           discovery algorithm, and may be different for each entry."
   DEFVAL { 300 }
   ::= { ptopoConfig 2 }


-- PTOPO MIB Notification Definitions
ptopoMIBNotifications  OBJECT IDENTIFIER ::= { ptopoMIB 2 }
ptopoMIBTrapPrefix     OBJECT IDENTIFIER ::=



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     { ptopoMIBNotifications 0 }

ptopoConfigChange NOTIFICATION-TYPE
   OBJECTS       {
            ptopoConnTabInserts,
            ptopoConnTabDeletes,
            ptopoConnTabDrops,
            ptopoConnTabAgeouts
   }
   STATUS        current
   DESCRIPTION
           "A ptopoConfigChange notification is sent when the value of
           ptopoLastChangeTime changes. It can be utilized by an NMS to
           trigger physical topology table maintenance polls.

           Note that transmission of ptopoConfigChange notifications
           are throttled by the agent, as specified by the
           'ptopoConfigTrapInterval' object."
  ::= { ptopoMIBTrapPrefix 1 }


-- PTOPO Registration Points
ptopoRegistrationPoints  OBJECT IDENTIFIER ::= { ptopoMIB 3 }

-- values used with ptopoConnDiscAlgorithm object
ptopoDiscoveryMechanisms OBJECT IDENTIFIER ::=
     { ptopoRegistrationPoints 1 }

ptopoDiscoveryLocal      OBJECT IDENTIFIER ::=
     { ptopoDiscoveryMechanisms 1 }


-- conformance information
ptopoConformance OBJECT IDENTIFIER ::= { ptopoMIB 4 }

ptopoCompliances OBJECT IDENTIFIER ::= { ptopoConformance 1 }
ptopoGroups      OBJECT IDENTIFIER ::= { ptopoConformance 2 }


-- compliance statements
ptopoCompliance MODULE-COMPLIANCE
  STATUS  current
   DESCRIPTION
           "The compliance statement for SNMP entities which implement
           the PTOPO MIB."
   MODULE  -- this module
       MANDATORY-GROUPS {
             ptopoDataGroup,



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             ptopoGeneralGroup,
             ptopoConfigGroup,
             ptopoNotificationsGroup
       }
   ::= { ptopoCompliances 1 }

-- MIB groupings
ptopoDataGroup   OBJECT-GROUP
   OBJECTS {
        ptopoConnRemoteChassisType,
        ptopoConnRemoteChassis,
        ptopoConnRemotePortType,
        ptopoConnRemotePort,
        ptopoConnDiscAlgorithm,
        ptopoConnAgentNetAddrType,
        ptopoConnAgentNetAddr,
        ptopoConnMultiMacSASeen,
        ptopoConnMultiNetSASeen,
        ptopoConnIsStatic,
        ptopoConnLastVerifyTime,
        ptopoConnRowStatus
   }
   STATUS  current
   DESCRIPTION
           "The collection of objects which are used to represent
           physical topology information for which a single agent
           provides management information.

           This group is mandatory for all implementations of the PTOPO
           MIB."
   ::= { ptopoGroups 1 }

ptopoGeneralGroup    OBJECT-GROUP
   OBJECTS {
        ptopoLastChangeTime,
        ptopoConnTabInserts,
        ptopoConnTabDeletes,
        ptopoConnTabDrops,
        ptopoConnTabAgeouts
   }
   STATUS  current
   DESCRIPTION
           "The collection of objects which are used to report the
           general status of the PTOPO MIB implementation.

           This group is mandatory for all agents which implement the
           PTOPO MIB."
   ::= { ptopoGroups 2 }



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ptopoConfigGroup    OBJECT-GROUP
   OBJECTS {
        ptopoConfigTrapInterval,
        ptopoConfigMaxHoldTime
   }
   STATUS  current
   DESCRIPTION
           "The collection of objects which are used to configure the
           PTOPO MIB implementation behavior.

           This group is mandatory for agents which implement the PTOPO
           MIB."
   ::= { ptopoGroups 3 }

ptopoNotificationsGroup NOTIFICATION-GROUP
   NOTIFICATIONS {
        ptopoConfigChange
   }
   STATUS        current
   DESCRIPTION
           "The collection of notifications used to indicate PTOPO MIB
           data consistency and general status information.

           This group is mandatory for agents which implement the PTOPO
           MIB."
   ::= { ptopoGroups 4 }

END

5.  Intellectual Property

  The IETF takes no position regarding the validity or scope of any
  intellectual property or other rights that might be claimed to
  pertain to the implementation or use of the technology described in
  this document or the extent to which any license under such rights
  might or might not be available; neither does it represent that it
  has made any effort to identify any such rights.  Information on the
  IETF's procedures with respect to rights in standards-track and
  standards-related documentation can be found in BCP-11.  Copies of
  claims of rights made available for publication and any assurances of
  licenses to be made available, or the result of an attempt made to
  obtain a general license or permission for the use of such
  proprietary rights by implementors or users of this specification can
  be obtained from the IETF Secretariat.

  The IETF invites any interested party to bring to its attention any
  copyrights, patents or patent applications, or other proprietary
  rights which may cover technology that may be required to practice



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  this standard.  Please address the information to the IETF Executive
  Director.

  The IETF has been notified of intellectual property rights claimed in
  regard to some or all of the specification contained in this
  document.  For more information consult the online list of claimed
  rights.

6.  Acknowledgements

  The PTOPO Discovery Protocol is a product of the IETF PTOPOMIB
  Working Group.

7.  References

  [RFC1155]   Rose, M. and K. McCloghrie, "Structure and Identification
              of Management Information for TCP/IP-based Internets",
              STD 16, RFC 1155, May 1990.

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

  [RFC1212]   Rose, M. and K. McCloghrie, "Concise MIB Definitions",
              STD 16, RFC 1212, March 1991.

  [RFC1215]   Rose, M., "A Convention for Defining Traps for use with
              the SNMP", RFC 1215, March 1991.

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

  [RFC1700]   Reynolds, J. and J. Postel, "Assigned Numbers", STD 2,
              RFC 1700, October 1994.

  [RFC1901]   Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
              "Introduction to Community-based SNMPv2", January 1996.

  [RFC1902]   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,
              January 1996.

  [RFC1903]   Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
              "Textual Conventions for version 2 of the Simple Network
              Management Protocol (SNMPv2)", RFC 1903, January 1996.




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RFC 2922                 Physical Topology MIB            September 2000


  [RFC1904]   Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
              "Conformance Statements for version 2 of the Simple
              Network Management Protocol (SNMPv2)", RFC 1904, January
              1996.

  [RFC1905]   Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
              "Protocol Operations for Version 2 of the Simple Network
              Management Protocol (SNMPv2)", RFC 1905, January 1996.

  [RFC1906]   Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
              "Transport Mappings for Version 2 of the  Simple Network
              Management Protocol (SNMPv2)", RFC 1906, January 1996.

  [RFC2021]   Waldbusser, S., "Remote Network Monitoring MIB (RMON-2)",
              RFC 2021, January 1997.

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

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

  [RFC2233]   McCloghrie, K. and F. Kastenholtz, "The Interfaces Group
              MIB using SMIv2", RFC 2233, November 1997.

  [RFC2570]   Case, J., Mundy, R., Partain, D. and B. Stewart,
              "Introduction to Version 3 of the Internet-standard
              Network Management Framework", RFC 2570, April 1999.

  [RFC2571]   Harrington, D., Presuhn, R. and B. Wijnen, "An
              Architecture for Describing SNMP Management Frameworks",
              RFC 2571, April 1999.

  [RFC2572]   Case, J., Harrington D., Presuhn R. and B. Wijnen,
              "Message Processing and Dispatching for the Simple
              Network Management Protocol (SNMP)", RFC 2572, April
              1999.

  [RFC2573]   Levi, D., Meyer, P. and B. Stewart, "SNMPv3
              Applications", RFC 2573, April 1999.

  [RFC2574]   Blumenthal, U. and B. Wijnen, "User-based Security Model
              (USM) for version 3 of the Simple Network Management
              Protocol (SNMPv3)", RFC 2574, April 1999.





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RFC 2922                 Physical Topology MIB            September 2000


  [RFC2575]   Wijnen, B., Presuhn, R. and K. McCloghrie, "View-based
              Access Control Model (VACM) for the Simple Network
              Management Protocol (SNMP)", RFC 2575, April 1999.

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

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

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

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

8.  Security Considerations

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

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

      read-create objects:  ptopoConnRemoteChassisType
         ptopoConnRemoteChassis ptopoConnRemotePortType
         ptopoConnRemotePort ptopoConnAgentNetAddrType
         ptopoConnAgentNetAddr ptopoConnIsStatic
         ptopoConfigTrapInterval ptopoConfigMaxHoldTime

      read-only objects:  ptopoConnDiscAlgorithm
         ptopoConnMultiMacSASeen ptopoConnMultiNetSASeen
         ptopoConnLastVerifyTime ptopoLastChangeTime

      notifications:  ptopoConfigChange

  These MIB objects expose information about the physical connectivity
  for a particular portion of a network.





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  A network administrator may also wish to inhibit transmission of any
  ptopoConfigChange notification by setting the ptopoConfigTrapInterval
  object to zero.

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

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

  It is recommended that the implementers consider the security
  features as provided by the SNMPv3 framework.  Specifically, the use
  of the User-based Security Model RFC 2574 [RFC2574] and the View-
  based Access Control Model RFC 2575 [RFC2575] is recommended.

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

9.  Authors' Addresses

  Andy Bierman
  Cisco Systems
  170 West Tasman Drive
  San Jose, CA USA 95134

  Phone: +1 408-527-3711
  EMail: [email protected]


  Kendall S. Jones
  Nortel Networks
  4401 Great America Parkway
  Santa Clara, CA USA 95054

  Phone: +1 408-495-7356
  EMail: [email protected]








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10.  Full Copyright Statement

  Copyright (C) The Internet Society (2000).  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.

Acknowledgement

  Funding for the RFC Editor function is currently provided by the
  Internet Society.



















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