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RFC 1229 - Extensions to the generic-interface MIB


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Network Working Group                              K. McCloghrie, Editor
Request for Comments: 1229                      Hughes LAN Systems, Inc.
                                                                May 1991

                Extensions to the Generic-Interface MIB

Status of this Memo

   This RFC contains definitions of managed objects used as experimental
   extensions to the generic interfaces structure of MIB-II.  This memo
   is a product of the SNMP Working Group of the Internet Engineering
   Task Force (IETF).  This RFC specifies an IAB standards track
   protocol for the Internet community, and requests discussion and
   suggestions for improvements.  Please refer to the current edition of
   the "IAB Official Protocol Standards" for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Table of Contents

   1. Abstract ..............................................    1
   2. The Network Management Framework.......................    1
   3. Objects ...............................................    2
   4. Overview ..............................................    3
   4.1 Generic Interface Extension Table ....................    3
   4.2 Generic Interface Test Table .........................    3
   4.3 Generic Receive Address Table ........................    4
   5. Definitions ...........................................    5
   6. Acknowledgements ......................................   14
   7. References ............................................   15
   8. Security Considerations................................   15
   9. Author's Address.......................................   16

1.  Abstract

   This memo defines an experimental portion of the Management
   Information Base (MIB) for use with network management protocols in
   TCP/IP-based internets.  In particular, it defines managed object
   types as experimental extensions to the generic interfaces structure
   of MIB-II.

2.  The Network Management Framework

   The Internet-standard Network Management Framework consists of three
   components.  They are:

      RFC 1155 which defines the SMI, the mechanisms used for describing
      and naming objects for the purpose of management.  RFC 1212

      defines a more concise description mechanism, which is wholly
      consistent with the SMI.

      RFC 1156 which defines MIB-I, the core set of managed objects for
      the Internet suite of protocols.  RFC 1213, defines MIB-II, an
      evolution of MIB-I based on implementation experience and new
      operational requirements.

      RFC 1157 which defines the SNMP, the protocol used for network
      access to managed objects.

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

3.  Objects

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the subset of Abstract Syntax Notation One (ASN.1) [7]
   defined in the SMI.  In particular, each object has a name, a syntax,
   and an encoding.  The name is an object identifier, an
   administratively assigned name, which specifies an object type.  The
   object type together with an object instance serves to uniquely
   identify a specific instantiation of the object.  For human
   convenience, we often use a textual string, termed the OBJECT
   DESCRIPTOR, to also refer to the object type.

   The syntax of an object type defines the abstract data structure
   corresponding to that object type.  The ASN.1 language is used for
   this purpose.  However, the SMI [3] purposely restricts the ASN.1
   constructs which may be used.  These restrictions are explicitly made
   for simplicity.

   The encoding of an object type is simply how that object type is
   represented using the object type's syntax.  Implicitly tied to the
   notion of an object type's syntax and encoding is how the object type
   is represented when being transmitted on the network.

   The SMI specifies the use of the basic encoding rules of ASN.1 [8],
   subject to the additional requirements imposed by the SNMP.

   Section 5 contains the specification of all object types in this
   section of the MIB.  The object types are defined using the
   conventions specified in the SMI, as amended by the extensions
   specified in [9].

4.  Overview

   The Internet Standard MIB [4,6] contains a group of management
   objects pertaining to a network device's generic network
   interface(s).  These objects are generic in the sense that they apply
   to all network interfaces, irrespective of the type of communication
   media and protocols used on such interfaces.  This has proved to be
   necessary but not sufficient; there are efforts underway to define
   additional MIB objects which are specific to particular media and
   lower-level (subnetwork-layer and below) protocol stacks.

   However, some of these efforts have identified objects which are
   required (or at least useful), but are not specific to the
   interface-type on which the effort is focusing.  In order to avoid
   redundancy, it is better that such objects be defined as extensions
   to the generic interface group, rather than defined in multiple
   specific-interface-type MIBs.

   This memo defines the resultant extensions to the generic interface
   group.  These extensions are spread over three tables: the generic
   Interface Extension table, the generic Interface Test table, and the
   generic Receive Address table.

4.1.  Generic Interface Extension Table

   This table consists of new objects applicable to all types of
   subnetwork interface.

4.2.  Generic Interface Test Table

   This section defines objects which allow a network manager to
   instruct an agent to test an interface for various faults.  A few
   common types of tests are defined in this document but most will be
   defined elsewhere, dependent on the particular type of interface.
   After testing, the object ifExtnsTestResult can be read to determine
   the outcome.  If an agent cannot perform the test, ifExtnsTestResult
   is set to so indicate.  The object ifExtnsTestCode can be used to
   provide further test-specific or interface-specific (or even
   enterprise-specific) information concerning the outcome of the test.
   Only one test can be in progress on each interface at any one time.
   If one test is in progress when another test is invoked, the second
   test is rejected.  Some agents may reject a test when a prior test is
   active on another interface.

   When a test is invoked, the identity of the originator of the request
   and the request-id are saved by the agent in the objects
   ifExtnsTestRequestId and ifExtnsTestCommunity.  These values remain
   set until the next test is invoked.  In the (rare) event that the

   invocation of tests by two network managers were to overlap, then
   there would be a possibility that the first test's results might be
   overwritten by the second test's results prior to the first results
   being read.  This unlikely circumstance can be detected by a network
   manager retrieving ifExtnsTestCommunity, and ifExtnsTestRequestId at
   the same time as the test results are retrieved, and ensuring that
   the results are for the desired request.

   In general, a Management station must not retransmit a request to
   invoke a test for which it does not receive a response; instead, it
   properly inspects an agent's MIB to determine if the invocation was
   successful.  The invocation request is retransmitted only if the
   invocation was unsuccessful.

   Some tests may require the interface to be taken off-line or may even
   require the agent to be rebooted after completion of the test.  In
   these circumstances, communication with the management station
   invoking the test may be lost until after completion of the test.
   The agent should make every effort to transmit a response to the
   request that invoked the test prior to losing communication.  When
   the agent is restored to normal service, the results of the test are
   properly made available in the appropriate objects.  Note that this
   requires that the ifIndex value assigned to an interface must be
   unchanged even if the test causes a reboot.  An agent must reject any
   test for which it cannot, perhaps due to resource constraints, make
   available at least the minimum amount of information after that test
   completes.

4.3.  Generic Receive Address Table

   This table contains objects relating to an interface's support for
   receiving packets/frames at more than one address on the same
   interface.

5.  Definitions

          RFC1229-MIB DEFINITIONS ::= BEGIN

          --        Extensions to MIB-II's Generic Interface Table

          IMPORTS
                  experimental, Counter         FROM RFC1155-SMI
                  DisplayString, PhysAddress    FROM RFC1213-MIB
                  OBJECT-TYPE                   FROM RFC-1212;

          ifExtensions  OBJECT IDENTIFIER ::= { experimental 6 }

          --   Generic Interface Extension Table
          --
          --  This group of objects is mandatory for all types of
          --  subnetwork interface.

          ifExtnsTable  OBJECT-TYPE
                  SYNTAX SEQUENCE OF IfExtnsEntry
                  ACCESS not-accessible
                  STATUS mandatory
                  DESCRIPTION
                         "A list of interfaces extension entries.
                          The number of entries is given by the value
                          of ifNumber, defined in [4,6]."
                  ::= { ifExtensions 1 }

          ifExtnsEntry  OBJECT-TYPE
                  SYNTAX IfExtnsEntry
                  ACCESS not-accessible
                  STATUS mandatory
                  DESCRIPTION
                         "An extension to the interfaces entry,
                          defined in [4,6], containing additional
                          objects at the subnetwork layer and below
                          for a particular interface."
                  INDEX  { ifExtnsIfIndex }
                  ::= { ifExtnsTable 1 }

          IfExtnsEntry ::=
                  SEQUENCE {
                      ifExtnsIfIndex

                          INTEGER,
                      ifExtnsChipSet
                          OBJECT IDENTIFIER,
                      ifExtnsRevWare
                          DisplayString,
                      ifExtnsMulticastsTransmittedOks
                          Counter,
                      ifExtnsBroadcastsTransmittedOks
                          Counter,
                      ifExtnsMulticastsReceivedOks
                          Counter,
                      ifExtnsBroadcastsReceivedOks
                          Counter,
                      ifExtnsPromiscuous
                          INTEGER
                  }

          ifExtnsIfIndex  OBJECT-TYPE
                  SYNTAX INTEGER
                  ACCESS read-only
                  STATUS mandatory
                  DESCRIPTION
                         "The value of this object identifies the
                          interface for which this entry contains
                          extended management information.  The value
                          of this object for a particular interface
                          has the same value as the ifIndex object,
                          defined in [4,6], for the same interface."
                  ::= { ifExtnsEntry 1 }

          ifExtnsChipSet  OBJECT-TYPE
                  SYNTAX OBJECT IDENTIFIER
                  ACCESS read-only
                  STATUS mandatory
                  DESCRIPTION
                         "This object identifies the hardware chip
                          set being used in the interface.  The
                          assignment of OBJECT IDENTIFIERs to various
                          types of hardware chip sets is managed
                          by the IANA.  If the hardware chip set is
                          unknown, the object identifier

                          unknownChipSet OBJECT IDENTIFIER ::= { 0 0 }

                          is returned.  Note that unknownChipSet is a
                          syntactically valid object identifier, and
                          any conformant implementation of ASN.1 and
                          the BER must be able to generate and

                          recognize this value."
                  ::= { ifExtnsEntry 2 }

          ifExtnsRevWare  OBJECT-TYPE
                  SYNTAX DisplayString (SIZE (0..255))
                  ACCESS read-only
                  STATUS mandatory
                  DESCRIPTION
                         "An arbitrary octet string that describes
                          the firmware version of this interface.
                          It is intended that this should be human
                          readable.  It must only contain ASCII
                          printable characters.  Typically this
                          will be the firmware version of the main
                          interface software."
                  ::= { ifExtnsEntry 3 }

          ifExtnsMulticastsTransmittedOks OBJECT-TYPE
                  SYNTAX Counter
                  ACCESS read-only
                  STATUS mandatory
                  DESCRIPTION
                         "The count of frames successfully
                          transmitted to a subnetwork or link-layer
                          multicast destination address other than a
                          broadcast address.  For a MAC layer protocol,
                          this includes both Group and Functional
                          addresses."
                  ::= { ifExtnsEntry 4 }

          ifExtnsBroadcastsTransmittedOks OBJECT-TYPE
                  SYNTAX Counter
                  ACCESS read-only
                  STATUS mandatory
                  DESCRIPTION
                         "The count of frames successfully
                          transmitted to a subnetwork or link-layer
                          broadcast addresses.  It does not include
                          frames sent to a multicast address."
                  ::= { ifExtnsEntry 5 }

          ifExtnsMulticastsReceivedOks OBJECT-TYPE
                  SYNTAX Counter
                  ACCESS read-only
                  STATUS mandatory
                  DESCRIPTION
                         "The count of frames successfully received
                          that are directed to an active subnetwork

                          or link-layer multicast address (for a MAC
                          layer protocol, this includes both Group and
                          Functional addresses). This does not include
                          frames directed to a broadcast address, nor
                          frames received with errors."
                  ::= { ifExtnsEntry 6 }

          ifExtnsBroadcastsReceivedOks OBJECT-TYPE
                  SYNTAX Counter
                  ACCESS read-only
                  STATUS mandatory
                  DESCRIPTION
                         "The count of frames successfully received
                          that are directed to a subnetwork or
                          link-layer broadcast address.  This does not
                          include frames received with errors."
                  ::= { ifExtnsEntry 7 }

          ifExtnsPromiscuous  OBJECT-TYPE
                  SYNTAX INTEGER {
                              true(1),
                              false(2)
                         }
                  ACCESS read-only  -- Note: agent implementors are
                                    -- encouraged to extend this
                                    -- access to read-write if that
                                    -- makes sense in their agent.
                  STATUS mandatory
                  DESCRIPTION
                         "This object has a value of false(2) if
                          this interface only accepts packets/frames
                          that are addressed to this station. This
                          object has a value of true(1) when the
                          station accepts all packets/frames
                          transmitted on the media.  The value
                          true(1) is only legal on certain types of
                          media.  If legal, setting this object to a
                          value of true(1) may require the interface
                          to be reset before becoming effective."
                  ::= { ifExtnsEntry 8 }

          --
          --    Generic Interface Test Table
          --
          -- This group of objects is optional, but if the table is
          -- implemented, all objects in the table must be implemented.

          ifExtnsTestTable   OBJECT-TYPE

                  SYNTAX  SEQUENCE OF IfExtnsTestEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "This table contains one entry per interface."
                  ::= { ifExtensions 2 }

          ifExtnsTestEntry OBJECT-TYPE
                  SYNTAX  IfExtnsTestEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "An entry containing objects for invoking
                           tests on an interface."
                  INDEX   { ifExtnsTestIfIndex }
                  ::= { ifExtnsTestTable 1 }

          IfExtnsTestEntry ::=
                  SEQUENCE {
                      ifExtnsTestIfIndex
                          INTEGER,
                      ifExtnsTestCommunity
                          OCTET STRING,
                      ifExtnsTestRequestId
                          INTEGER,
                      ifExtnsTestType
                          OBJECT IDENTIFIER,
                      ifExtnsTestResult
                          INTEGER,
                      ifExtnsTestCode
                          OBJECT IDENTIFIER
                  }

          ifExtnsTestIfIndex  OBJECT-TYPE
                  SYNTAX  INTEGER
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                         "The value of this object identifies the
                          interface for which this entry contains
                          information on interface tests.  The value
                          of this object for a particular interface
                          has the same value as the ifIndex object,
                          defined in [4,6], for the same interface."
                  ::= { ifExtnsTestEntry 1 }

          ifExtnsTestCommunity  OBJECT-TYPE
                  SYNTAX  OCTET STRING
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                         "This object contains the name of the SNMP
                          authentication community [5] which was used
                          to authenticate the SNMP Message which invoked
                          the current or most recent test on this
                          interface.  If the authentication community
                          is unknown or undefined, this value contains
                          the zero-length string."
                  ::= { ifExtnsTestEntry 2 }

          ifExtnsTestRequestId  OBJECT-TYPE
                  SYNTAX  INTEGER
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                         "This object contains the value of the
                          request-id field in the SNMP PDU [5] which
                          invoked the current or most recent test on
                          this interface.  If the request-id is
                          unknown or undefined, this value contains
                          the value zero."
                  ::= { ifExtnsTestEntry 3 }

          ifExtnsTestType  OBJECT-TYPE
                  SYNTAX  OBJECT IDENTIFIER
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                         "A control variable used to start and stop
                          operator-initiated interface tests.
                              Most OBJECT IDENTIFIER values assigned
                          to tests are defined elsewhere, in associ-
                          ation with specific types of interface.
                          However, this document assigns a value for
                          a full-duplex loopback test, and defines the
                          special meanings of the subject identifier:

                            noTest  OBJECT IDENTIFIER ::= { 0 0 }

                          When the value noTest is written to this
                          object, no action is taken unless a test is
                          in progress, in which case the test is
                          aborted.  Writing any other value to this
                          object is only valid when no test is

                          currently in progress, in which case the
                          indicated test is initiated.
                              Note that noTest is a syntactically valid
                          object identifier, and any conformant
                          implementation of ASN.1 and BER must be able
                          to generate and recognize this value.
                              When read, this object always returns
                          the most recent value that ifExtnsTestType
                          was set to.  If it has not been set since
                          the last initialization of the network
                          management subsystem on the agent, a value
                          of noTest is returned."
                  ::= { ifExtnsTestEntry 4 }

          wellKnownTests OBJECT IDENTIFIER ::= { ifExtensions 4 }

          --  full-duplex loopback test
          testFullDuplexLoopBack OBJECT IDENTIFIER ::=
                                                  { wellKnownTests 1 }

          ifExtnsTestResult  OBJECT-TYPE
                  SYNTAX  INTEGER {
                              none(1),        -- no test yet requested
                              success(2),
                              inProgress(3),
                              notSupported(4),
                              unAbleToRun(5), -- due to state of system
                              aborted(6),
                              failed(7)
                          }
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                         "This object contains the result of the most
                          recently requested test, or the value
                          none(1) if no tests have been requested since
                          the last reset.  Note that this facility
                          provides no provision for saving the results
                          of one test when starting another, as could
                          be required if used by multiple managers
                          concurrently."
                  ::= { ifExtnsTestEntry 5 }

          ifExtnsTestCode  OBJECT-TYPE
                  SYNTAX  OBJECT IDENTIFIER
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION

                         "This object contains a code which contains
                          more specific information on the test result,
                          for example an error-code after a failed
                          test.  Error codes and other values this
                          object may take are specific to the type of
                          interface and/or test.  However, one subject
                          identifier:

                          testCodeUnknown  OBJECT IDENTIFIER ::= { 0 0 }

                          for use if no additional result code is
                          available.
                              Note that testCodeUnknown is a
                          syntactically valid object identifier, and
                          any conformant implementation of ASN.1 and
                          the BER must be able to generate and
                          recognize this value."
                  ::= { ifExtnsTestEntry 6 }

          --   Generic Receive Address Table
          --
          -- This group of objects is mandatory for all types of
          -- interfaces which can receive packets/frames addressed to
          -- more than one address.

          ifExtnsRcvAddrTable  OBJECT-TYPE
                  SYNTAX SEQUENCE OF IfExtnsRcvAddrEntry
                  ACCESS not-accessible
                  STATUS mandatory
                  DESCRIPTION
                         "This table contains an entry for each
                          address (broadcast, multicast, or uni-cast)
                          for which the system will receive packets/
                          frames on a particular interface.  When an
                          interface is operating in promiscuous mode,
                          entries are only required for those addresses
                          for which the system would receive frames
                          were it not operating in promiscuous mode."
                  ::= { ifExtensions 3 }

          ifExtnsRcvAddrEntry  OBJECT-TYPE
                  SYNTAX IfExtnsRcvAddrEntry
                  ACCESS not-accessible
                  STATUS mandatory
                  DESCRIPTION
                         "A list of objects identifying an address
                          for which the system will accept packets/

                          frames on a particular interface."
                  INDEX  { ifExtnsRcvAddrIfIndex, ifExtnsRcvAddress }
                  ::= { ifExtnsRcvAddrTable 1 }

          IfExtnsRcvAddrEntry ::=
                  SEQUENCE {
                      ifExtnsRcvAddrIfIndex
                          INTEGER,
                      ifExtnsRcvAddress
                          PhysAddress,
                      ifExtnsRcvAddrStatus
                          INTEGER
                  }

          ifExtnsRcvAddrIfIndex  OBJECT-TYPE
                  SYNTAX INTEGER
                  ACCESS read-only
                  STATUS mandatory
                  DESCRIPTION
                         "The value of ifIndex, defined in [4,6], of an
                          interface which recognizes this entry's
                          address."
                  ::= { ifExtnsRcvAddrEntry 1 }

          ifExtnsRcvAddress OBJECT-TYPE
                  SYNTAX PhysAddress
                  ACCESS read-only
                  STATUS mandatory
                  DESCRIPTION
                         "An address for which the system will accept
                          packets/frames on this entry's interface."
                  ::= { ifExtnsRcvAddrEntry 2 }

          ifExtnsRcvAddrStatus OBJECT-TYPE
                  SYNTAX INTEGER {
                             other(1),
                             invalid(2),
                             volatile(3),
                             nonVolatile(4)
                         }
                  ACCESS read-write
                  STATUS mandatory
                  DESCRIPTION
                         "This object has the value nonVolatile(4)
                          for those entries in the table which are
                          valid and will not be deleted by the next
                          restart of the managed system.  Entries
                          having the value volatile(3) are valid

                          and exist, but have not been saved, so
                          that will not exist after the next
                          restart of the managed system.  Entries
                          having the value other(1) are valid and
                          exist but are not classified as to whether
                          they will continue to exist after the next
                          restart.  Entries having the value invalid(2)
                          are invalid and do not represent an address
                          for which an interface accepts frames.
                              Setting an object instance to one of
                          the values other(1), volatile(3), or
                          nonVolatile(4) causes the corresponding
                          entry to exist or continue to exist, and
                          to take on the respective status as regards
                          the next restart of the managed system.
                              Setting an object instance to the value
                          invalid(2) causes the corresponding entry
                          to become invalid or cease to exist.
                              It is an implementation-specific matter
                          as to whether the agent removes an
                          invalidated entry from the table.
                          Accordingly, management stations must be
                          prepared to receive tabular information
                          from agents that corresponds to entries not
                          currently in use.  Proper interpretation of
                          such entries requires examination of the
                          relevant ifExtnsRcvAddrStatus object
                          instance."
                  DEFVAL  { volatile }
                  ::= { ifExtnsRcvAddrEntry 3 }

          END

6.  Acknowledgements

   Most of the MIB objects defined in this document were originally
   proposed as a part of a MIB for management of IEEE 802.5 Token Ring
   networks, as prepared by:

               Eric B. Decker, cisco Systems, Inc., and
               Richard Fox, Synoptics Inc.

   In addition, the comments of the following individuals are
   acknowledged:

               James R. Davin, MIT-LCS
               Stan Froyd, ACC
               Frank Kastenholz, Racal Interlan

               Dave Perkins, 3Com
               Marshall T. Rose, PSI
               Bob Stewart, Xyplex
               David Waitzman, BBN
               Wengyik Yeong, PSI

7.  References

   [1] Cerf, V., "IAB Recommendations for the Development of Internet
       Network Management Standards", RFC 1052, NRI, April 1988.

   [2] Cerf, V., "Report of the Second Ad Hoc Network Management Review
       Group", RFC 1109, NRI, August 1989.

   [3] 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.

   [4] McCloghrie K., and M. Rose, "Management Information Base for
       Network Management of TCP/IP-based internets", RFC 1156, Hughes
       LAN Systems, Performance Systems International, May 1990.

   [5] 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.

   [6] Rose M., Editor, "Management Information Base for Network
       Management of TCP/IP-based internets: MIB-II", RFC 1213,
       Performance Systems International, March 1991.

   [7] Information processing systems - Open Systems Interconnection -
       Specification of Abstract Syntax Notation One (ASN.1),
       International Organization for Standardization, International
       Standard 8824, December 1987.

   [8] Information processing systems - Open Systems Interconnection -
       Specification of Basic Encoding Rules for Abstract Notation One
       (ASN.1), International Organization for Standardization,
       International Standard 8825, December 1987.

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

8.  Security Considerations

   Security issues are not discussed in this memo.

9.   Author's Address

   Keith McCloghrie
   Hughes LAN Systems, Inc.
   1225 Charleston Road
   Mountain View, CA 94043

   Phone:    (415) 966-7934

   EMail: kzm@hls.com

 

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