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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
+
+
+
+SNMP Working Group                                              [Page 1]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+      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].
+
+
+
+
+
+
+SNMP Working Group                                              [Page 2]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+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
+
+
+
+SNMP Working Group                                              [Page 3]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+   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.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+SNMP Working Group                                              [Page 4]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+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
+
+
+
+SNMP Working Group                                              [Page 5]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+                          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
+
+
+
+SNMP Working Group                                              [Page 6]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+                          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
+
+
+
+SNMP Working Group                                              [Page 7]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+                          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.
+
+
+
+
+
+SNMP Working Group                                              [Page 8]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+          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 }
+
+
+
+
+SNMP Working Group                                              [Page 9]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+          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
+
+
+
+SNMP Working Group                                             [Page 10]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+                          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
+
+
+
+SNMP Working Group                                             [Page 11]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+                         "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/
+
+
+
+SNMP Working Group                                             [Page 12]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+                          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
+
+
+
+SNMP Working Group                                             [Page 13]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+                          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
+
+
+
+SNMP Working Group                                             [Page 14]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+               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.
+
+
+
+SNMP Working Group                                             [Page 15]
+
+RFC 1229                Interface MIB Extensions                May 1991
+
+
+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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+SNMP Working Group                                             [Page 16]
+
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