<pre>Network Working Group                                          D. Throop
Request for Comments: 1381                      Data General Corporation
                                                                F. Baker
                                        Advanced Computer Communications
                                                           November 1992


                    <span class="h1">SNMP MIB Extension for X.25 LAPB</span>

Status of this Memo

   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.

Abstract

   This memo defines a portion of the Management Information Base (MIB)
   for use with network management protocols in TCP/IP-based internets.
   In particular, it defines objects for managing the Link Layer of
   X.25, LAPB.  The objects defined here, along with the objects in the
   "SNMP MIB Extension for the Packet Layer of X.25" [<a href="#ref-9" title="&quot;SNMP MIB extension for the Packet Layer of X.25&quot;">9</a>] and the
   "Definitions of Managed Objects for RS-232-like Hardware Devices"
   [<a href="#ref-8" title="&quot;Definitions of Managed Objects for RS-232- like Hardware Devices&quot;">8</a>], combine to allow management of an X.25 protocol stack.

Table of Contents

   <a href="#section-1">1</a>. The Network Management Framework .......................    <a href="#page-2">2</a>
   <a href="#section-2">2</a>. Objects ................................................    <a href="#page-2">2</a>
   <a href="#section-2.1">2.1</a> Format of Definitions .................................    <a href="#page-3">3</a>
   <a href="#section-3">3</a>. Overview ...............................................    <a href="#page-3">3</a>
   <a href="#section-3.1">3.1</a> Informal overview .....................................    <a href="#page-3">3</a>
   <a href="#section-3.2">3.2</a> Textual Conventions ...................................    <a href="#page-4">4</a>
   <a href="#section-3.3">3.3</a> Formal overview .......................................    <a href="#page-4">4</a>
   <a href="#section-3.4">3.4</a> Tables ................................................    <a href="#page-5">5</a>
   <a href="#section-3.5">3.5</a> Traps .................................................    <a href="#page-6">6</a>
   <a href="#section-4">4</a>. Object Definitions .....................................    <a href="#page-6">6</a>
   <a href="#section-5">5</a>. Appendix: Revision History .............................   <a href="#page-27">27</a>
      July 30, 1992 ..........................................   <a href="#page-27">27</a>
      June 12, 1992 ..........................................   <a href="#page-27">27</a>
      May 18, 1992 ...........................................   <a href="#page-28">28</a>
      April 8, 1992 ..........................................   <a href="#page-28">28</a>
      February 1992 ..........................................   <a href="#page-28">28</a>
      October 1991 ...........................................   <a href="#page-29">29</a>
      June 1991 ..............................................   <a href="#page-30">30</a>
      April 1991 .............................................   <a href="#page-30">30</a>



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   <a href="#section-6">6</a>. Acknowledgements .......................................   <a href="#page-30">30</a>
   <a href="#section-7">7</a>. References .............................................   <a href="#page-31">31</a>
   <a href="#section-8">8</a>. Security Considerations ................................   <a href="#page-33">33</a>
   <a href="#section-9">9</a>. Authors' Addresses .....................................   <a href="#page-33">33</a>

<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>.  The Network Management Framework</span>

   The Internet-standard Network Management Framework consists of three
   components.  These components give the rules for defining objects,
   the definitions of objects, and the protocol for manipulating
   objects.

   The network management framework structures objects in an abstract
   information tree. The branches of the tree name objects and the
   leaves of the tree contain the values manipulated to effect
   management. This tree is called the Management Information Base or
   MIB. The concepts of this tree are given in STD 16/RFC 1155 "The
   Structure of Management Information" or SMI [<a href="#ref-1" title="&quot;Structure and Identification of Management Information for TCP/IP-based internets&quot;">1</a>]. The SMI defines the
   trunk of the tree and the types of objects used when defining the
   leaves. STD 16/RFC 1212, "Towards Concise MIB Definitions" [<a href="#ref-4" title="&quot;Concise MIB Definitions&quot;">4</a>],
   defines a more concise description mechanism that preserves all the
   principals of the SMI.

   The core MIB definitions for the Internet suite of protocols can be
   found in <a href="./rfc1156">RFC 1156</a> [<a href="#ref-2" title="&quot;Management Information Base for Network Management of TCP/IP-based internets&quot;">2</a>] "Management Information Base for Network
   Management of TCP/IP-based internets". STD 17/RFC 1213 [<a href="#ref-5" title="&quot;Management Information Base for Network Management of TCP/IP-based internets: MIB-II&quot;">5</a>] defines
   MIB-II, an evolution of MIB-I with changes to incorporate
   implementation experience and new operational requirements.

   STD 15/RFC 1157 [<a href="#ref-3" title="and J. Davin">3</a>] defines the SNMP protocol itself. The protocol
   defines how to manipulate the objects in a remote MIB.

   The tree structure of the MIB allows new objects to be defined for
   the purpose of experimentation and evaluation.

<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>.  Objects</span>

   The definition of an object in the MIB requires an object name and
   type.  Object names and types are defined using the subset of the
   Abstract Syntax Notation One (ASN.1) [<a href="#ref-6" title=" International Organization for Standardization">6</a>] defined in the SMI [<a href="#ref-1" title="&quot;Structure and Identification of Management Information for TCP/IP-based internets&quot;">1</a>].
   Objects are named using ASN.1 object identifiers, administratively
   assigned names, to specify object types. The object name, together
   with an optional object instance, uniquely identifies a specific
   instance of an object. For human convenience, we often use a textual
   string, termed the OBJECT DESCRIPTOR, to also refer to objects.

   Objects also have a syntax that defines the abstract data structure
   corresponding to that object type.  The ASN.1 language [<a href="#ref-6" title=" International Organization for Standardization">6</a>] provides



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   the primitives used for this purpose.  The SMI [<a href="#ref-1" title="&quot;Structure and Identification of Management Information for TCP/IP-based internets&quot;">1</a>] purposely
   restricts the ASN.1 constructs which may be used for simplicity and
   ease of implementation.  The encoding of an object type simply
   describes how to represent an object using ASN.1 encoding rules [<a href="#ref-7" title=" International Standard 8825">7</a>],
   for purposes of dealing with the SNMP protocol.

<span class="h3"><a class="selflink" id="section-2.1" href="#section-2.1">2.1</a>.  Format of Definitions</span>

   <a href="#section-4">Section 4</a> contains the specification of all object types defined in
   this MIB module. The object definitions use the conventions given in
   the SMI [<a href="#ref-1" title="&quot;Structure and Identification of Management Information for TCP/IP-based internets&quot;">1</a>] as amended by the concise MIB definitions [<a href="#ref-4" title="&quot;Concise MIB Definitions&quot;">4</a>].

<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>.  Overview</span>

<span class="h3"><a class="selflink" id="section-3.1" href="#section-3.1">3.1</a>.  Informal overview</span>

   This section describes how the objects defined below relate with
   other MIBs.  This section is only informational to help understand
   how the pieces fit together.

   The objects defined below are to be used in conjunction with MIB-II
   and other MIBs such as the X.25 packet level MIB [<a href="#ref-9" title="&quot;SNMP MIB extension for the Packet Layer of X.25&quot;">9</a>].  A system with
   a complete X.25 stack running over a synchronous line will have at
   least two interfaces in the ifTable defined in MIB-II.  There will be
   an interface for LAPB and another interface for the packet layer of
   X.25. There will also be objects defined in the RS-232-like MIB for
   the physical sync line.

   Each software interface identifies the layer below it used to send
   and receive packets. The X.25 MIB object, x25InfoDataLinkId,
   specifies an instance of lapbAdmnIndex for the LAPB interface under
   that X.25. The LAPB object, lapbOperPortId, defined below, identifies
   an instance of the rs232PortIndex for the the Sync line used by LAPB.

   For X.25 running over LAPB over Ethernet, the lapbAdmnPortId would
   identify the instance of ifIndex for the Ethernet interface.

   Each X.25 subnetwork will have separate entries in the ifTable.  Thus
   a system with two X.25 lines would have two ifTable entries for the
   two X.25 packet layers and two other entries for the two LAPB
   interfaces. Each X.25 Packet Layer MIB would identify the instance of
   the LAPB MIB below it. Each LAPB MIB would identify the Sync line
   below it. The system would also have two entries for rs232PortTable
   and rs232SyncPortTable for the two physical lines.

   Since the ifTable as defined in MIB-II is device independent, it
   doesn't have anything specific for any type of interface.  The
   objects below define the LAPB specific information for an interface



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   of type LAPB. Different LAPB interfaces can also be differentiated by
   matching the values of ifIndex with lapbAdmnIndex.

<span class="h3"><a class="selflink" id="section-3.2" href="#section-3.2">3.2</a>.  Textual Conventions</span>

   Two new data types are introduced as a textual conventions in this
   MIB document.  These textual conventions enhance the readability of
   the specification and can ease comparison with other specifications
   if appropriate.  It should be noted that the introduction of these
   textual conventions has no effect on either the syntax nor the
   semantics of any managed objects.  The use of these is merely an
   artifact of the explanatory method used.  Objects defined in terms of
   one of these methods are always encoded by means of the rules that
   define the primitive type.  Hence, no changes to the SMI or the SNMP
   are necessary to accommodate these textual conventions which are
   adopted merely for the convenience of readers and writers in pursuit
   of the elusive goal of clear, concise, and unambiguous MIB documents.

   This MIB introduces the data types of:

                    PositiveInteger
                    ifIndexType

<span class="h3"><a class="selflink" id="section-3.3" href="#section-3.3">3.3</a>.  Formal overview</span>

   Instances of the objects defined below represent attributes of a LAPB
   interface.  LAPB interfaces are identified by an ifType object in the
   Internet-standard MIB [<a href="#ref-5" title="&quot;Management Information Base for Network Management of TCP/IP-based internets: MIB-II&quot;">5</a>] of

                lapb(16).

   For these interfaces, the value of the ifSpecific variable in the
   MIB-II [<a href="#ref-5" title="&quot;Management Information Base for Network Management of TCP/IP-based internets: MIB-II&quot;">5</a>] has the OBJECT IDENTIFIER value:

                lapb    OBJECT IDENTIFIER ::= { transmission 16 }

   The relationship between a LAPB interface and an interface in the
   context of the Internet-standard MIB [<a href="#ref-5" title="&quot;Management Information Base for Network Management of TCP/IP-based internets: MIB-II&quot;">5</a>] is one-to-one.  As such, the
   value of an ifIndex object instance can be directly used to identify
   corresponding instances of the objects defined below.

   The objects defined below are defined in the context of ISO 7776 [<a href="#ref-10" title="&quot;Information processing systems - Data communication - High-level data link control procedure - Description of the X.25 LAPB- compatible DTE data link procedures&quot;">10</a>]
   and ISO 8885 [<a href="#ref-11" title="&quot;Information technology - Telecommunications and information exchange between systems - High-level data link control (HDLC) procedures - General purpose XID frame information field contents and format&quot;">11</a>]. Access to those documents maybe useful (but isn't
   essential) to understand the names and semantics of some objects.
   Where possible the object descriptions use the terminology of ISO
   7776; for example, one commonly used term refers to the peer LAPB as
   the DCE/remote DTE.  This terminology does not restrict the
   instrumented LAPB to function only as a DTE.  This MIB maybe applied



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   to a LAPB configured as either a DCE or a DTE.

   To the extent that some attributes defined in the Internet standard
   MIB [<a href="#ref-5" title="&quot;Management Information Base for Network Management of TCP/IP-based internets: MIB-II&quot;">5</a>] are applicable to LAPB, those objects have not been
   duplicated here.  In some instances some clarification of how to
   apply those objects to LAPB has been given.

   Some objects defined below include a DEFVAL clause. This clause
   provides reasonable (but not mandatory) default values to use when
   creating these objects.  This does not imply this MIB defines any
   mechanism for creating or deleting LAPB interfaces.  The creation and
   deletion of the objects of this MIB depend on the implementation
   method for creating and deleting LAPB interfaces.  The DEFVAL clause
   provides reasonable defaults to allow further extension of the MIB to
   define methods for creating and deleting LAPB interfaces without
   having to deprecate these objects for the lack of a DEFVAL clause.

<span class="h3"><a class="selflink" id="section-3.4" href="#section-3.4">3.4</a>.  Tables</span>

   This extension adds four tables to the MIB.  These tables are:

                       lapbAdmnTable,
                       lapbOperTable,
                       lapbFlowTable, and
                       lapbXidTable.

   The lapbAdmnTable provides objects for common parameters used by LAPB
   such as the T1 retransmission timer or the N2 retransmission counter.
   Changes to objects in this table need not affect a running interface
   but provides access to the values used to initialize an interface.
   These values are read-write.

   The lapbOperTable provides objects to determine the parameters
   actually in use by an interface.  These objects are read only.  The
   values currently in use maybe different from the lapbAdmnTable values
   if the lapbAdmnTable was changed after interface initialization or if
   XID negotiation selected different values.

   The lapbFlowTable provides objects that report how the LAPB interface
   performs.  These are read-only objects used to monitor operation.

   The lapbXidTable is not required for systems that do not transmit XID
   frames. For systems that do transmit XID frames, this table provides
   the values for the fields of the XID frame that are not already
   present in the lapbAdmnTable.  The objects in this table are read-
   write.





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<span class="h3"><a class="selflink" id="section-3.5" href="#section-3.5">3.5</a>.  Traps</span>

   Since all LAPB interfaces have entries in the ifTable, significant
   changes in the state of the interface should send a linkUp or
   linkDown trap. Thus an interface that receives or sends a Frame
   Reject frame should send a linkDown trap.  If the interface later
   comes back up, it should then send a linkUP trap.

<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>.  Object Definitions</span>


          <a href="./rfc1381">RFC1381</a>-MIB DEFINITIONS ::= BEGIN

          IMPORTS
                  Counter
                          FROM <a href="./rfc1155">RFC1155</a>-SMI
                  transmission
                          FROM <a href="./rfc1213">RFC1213</a>-MIB
                  OBJECT-TYPE
                          FROM <a href="./rfc1212">RFC-1212</a>;


                          --  LAPB MIB

          lapb    OBJECT IDENTIFIER ::= { transmission 16 }

          PositiveInteger ::= INTEGER (0..2147483647)

          IfIndexType     ::= INTEGER (1..2147483647)
          -- IfIndexType specifies an index object for a table
          -- with entries that match entries in the MIB-II ifTable.
          -- The value of the index for the table will match the
          -- ifIndex entry for same interface in the ifTable.
          -- The values of this object range from 1 to ifNumber
          -- inclusive.


          -- ###########################################################
          --                      LAPB Admn Table
          -- ###########################################################

          -- Support of the lapbAdmnTable is mandatory for all
          -- agents of systems that implement LAPB.

          lapbAdmnTable   OBJECT-TYPE
                  SYNTAX  SEQUENCE OF LapbAdmnEntry
                  ACCESS  not-accessible
                  STATUS  mandatory



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                  DESCRIPTION
                          "This table contains objects that can be
                          changed to manage a LAPB interface.
                          Changing one of these parameters may take
                          effect in the operating LAPB immediately or
                          may wait until the interface is restarted
                          depending on the details of the
                          implementation.

                          Most of the objects in this read-write table
                          have corresponding read-only objects in the
                          lapbOperTable that return the current
                          operating value.

                          The operating values may be different from
                          these configured values if changed by XID
                          negotiation or if a configured parameter was
                          changed after the interface was started."
                  ::= { lapb 1 }

          lapbAdmnEntry   OBJECT-TYPE
                  SYNTAX  LapbAdmnEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "Configured parameter values for a specific
                          LAPB."
                  INDEX { lapbAdmnIndex }
                  ::= { lapbAdmnTable 1 }

          LapbAdmnEntry ::= SEQUENCE {
                  lapbAdmnIndex
                          IfIndexType,
                  lapbAdmnStationType
                          INTEGER,
                  lapbAdmnControlField
                          INTEGER,
                  lapbAdmnTransmitN1FrameSize
                          PositiveInteger,
                  lapbAdmnReceiveN1FrameSize
                          PositiveInteger,
                  lapbAdmnTransmitKWindowSize
                          INTEGER,
                  lapbAdmnReceiveKWindowSize
                          INTEGER,
                  lapbAdmnN2RxmitCount
                  INTEGER,
                  lapbAdmnT1AckTimer



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                          PositiveInteger,
                  lapbAdmnT2AckDelayTimer
                          PositiveInteger,
                  lapbAdmnT3DisconnectTimer
                          PositiveInteger,
                  lapbAdmnT4IdleTimer
                          PositiveInteger,
                  lapbAdmnActionInitiate
                          INTEGER,
                  lapbAdmnActionRecvDM
                          INTEGER
                  }

          lapbAdmnIndex   OBJECT-TYPE
                  SYNTAX  IfIndexType
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The ifIndex value for the LAPB interface."
                  ::= { lapbAdmnEntry 1 }

          lapbAdmnStationType     OBJECT-TYPE
                  SYNTAX  INTEGER {
                          dte (1),
                          dce (2),
                          dxe (3)
                          }
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "Identifies the desired station type of this
                          interface."
                  REFERENCE "ISO 7776 <a href="#section-3.1">section 3.1</a>"
                  DEFVAL { dte }
                  ::= { lapbAdmnEntry 2 }

          lapbAdmnControlField OBJECT-TYPE
                  SYNTAX  INTEGER {
                          modulo8 (1),
                          modulo128 (2)
                          }
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The desired size of the sequence numbers
                          used to number frames."
                  REFERENCE "ISO 8885 Table 3, Name: HDLC Option - 10"
                  DEFVAL { modulo8 }



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                  ::= { lapbAdmnEntry 3 }

          lapbAdmnTransmitN1FrameSize OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The default maximum N1 frame size desired
                          in number of bits for a frame transmitted by
                          this DTE.  This excludes flags and 0 bits
                          inserted for transparency."
                  REFERENCE "ISO 8885 Table 3,
                          Name: Information Field length"
                  DEFVAL { 36000 } -- 4500 * 8; 802.5 Frame size
                  ::= { lapbAdmnEntry 4 }

          lapbAdmnReceiveN1FrameSize OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The default maximum N1 frame size desired
                          in number of bits for a frame the DCE/remote
                          DTE transmits to this DTE.  This excludes
                          flags and 0 bits inserted for transparency."
                  DEFVAL { 36000  } -- 4500 * 8; 802.5 Frame size
                  ::= { lapbAdmnEntry 5 }

          lapbAdmnTransmitKWindowSize OBJECT-TYPE
                  SYNTAX  INTEGER (1..127)
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The default transmit window size for this
                          Interface.  This is the maximum number of
                          unacknowledged sequenced PDUs that may be
                          outstanding from this DTE at any one time."
                  REFERENCE "ISO 8885 Table 3, Name: Window size"
                  DEFVAL { 7 }
                  ::= { lapbAdmnEntry 6 }

          lapbAdmnReceiveKWindowSize OBJECT-TYPE
                  SYNTAX  INTEGER (1..127)
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The default receive window size for this
                          Interface.  This is the maximum number of



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                          unacknowledged sequenced PDUs that may be
                          outstanding from the DCE/remote DTE at any
                          one time."
                  REFERENCE "ISO 8885 Table 3, Name: Window size"
                  DEFVAL { 7 }
                  ::= { lapbAdmnEntry 7 }

          lapbAdmnN2RxmitCount    OBJECT-TYPE
                  SYNTAX  INTEGER (0..65535)
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The default N2 retry counter for this
                          interface.  This specifies the number of
                          times a PDU will be resent after the T1
                          timer expires without an acknowledgement for
                          the PDU."
                  REFERENCE "ISO 8885 Table 3,
                          Name: Retransmission Attempts"
                  DEFVAL { 20 }
                  ::= { lapbAdmnEntry 8 }

          lapbAdmnT1AckTimer      OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The default T1 timer for this interface.
                          This specifies the maximum time in
                          Milliseconds to wait for acknowledgment of a
                          PDU."
                  REFERENCE "ISO 8885 Table 3, Name:
                          Acknowledgement timer"
                  DEFVAL { 3000 }
                  ::= { lapbAdmnEntry 9 }

          lapbAdmnT2AckDelayTimer         OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The default T2 timer for this interface.
                          This specifies the maximum time in
                          Milliseconds to wait before sending an
                          acknowledgment for a sequenced PDU.  A value
                          of zero means there will be no delay in
                          acknowledgement generation."
                  REFERENCE "ISO 8885 Table 3,



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                          Name: Reply delay timer"
                  DEFVAL { 0 }
                  ::= { lapbAdmnEntry 10 }

          lapbAdmnT3DisconnectTimer OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The T3 timer for this interface.  This
                          specifies the time in Milliseconds to wait
                          before considering the link disconnected.  A
                          value of zero indicates the link will be
                          considered disconnected upon completion of
                          the frame exchange to disconnect the link."
                  REFERENCE "ISO 7776 <a href="#section-5.7.1.3">section 5.7.1.3</a>"
                  DEFVAL { 60000 }
                  ::= { lapbAdmnEntry 11 }

          lapbAdmnT4IdleTimer OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The T4 timer for this interface.  This
                          specifies the maximum time in Milliseconds
                          to allow without frames being exchanged on
                          the data link.  A value of 2147483647
                          indicates no idle timer is being kept."
                  REFERENCE "ISO 7776 <a href="#section-5.7.1.4">section 5.7.1.4</a>"
                  DEFVAL { 2147483647 }
                  ::= { lapbAdmnEntry 12 }

          lapbAdmnActionInitiate OBJECT-TYPE
                  SYNTAX  INTEGER {
                  sendSABM (1),
                          sendDISC (2),
                          sendDM (3),
                          none (4),
                          other (5)
                          }
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "This identifies the action LAPB will take
                          to initiate link set-up."
                  DEFVAL { sendSABM }
                  ::= { lapbAdmnEntry 13 }



<span class="grey">Throop &amp; Baker                                                 [Page 11]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-12" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


          lapbAdmnActionRecvDM OBJECT-TYPE
                  SYNTAX  INTEGER {
                          sendSABM (1),
                          sendDISC (2),
                          other (3)
                          }
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "This identifies the action LAPB will take
                          when it receives a DM response."
                  DEFVAL { sendSABM }
                  ::= { lapbAdmnEntry 14 }


          -- ###########################################################
          --                      LAPB operating parameters.
          -- ###########################################################

          -- Support of the lapbOperTable is mandatory for all
          -- agents of systems that implement LAPB.

          lapbOperTable   OBJECT-TYPE
                  SYNTAX  SEQUENCE OF LapbOperEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "This table contains configuration
                          information about interface parameters
                          currently set in the interface.  Many of
                          these objects have corresponding objects in
                  the lapbAdmnTable."
                  ::= { lapb 2 }

          lapbOperEntry   OBJECT-TYPE
                  SYNTAX  LapbOperEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "Currently set parameter values for a
                          specific LAPB."
                  INDEX { lapbOperIndex }
                  ::= { lapbOperTable 1 }

          LapbOperEntry ::= SEQUENCE {
                  lapbOperIndex
                          IfIndexType,
                  lapbOperStationType



<span class="grey">Throop &amp; Baker                                                 [Page 12]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-13" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                          INTEGER,
                  lapbOperControlField
                          INTEGER,
                  lapbOperTransmitN1FrameSize
                          PositiveInteger,
                  lapbOperReceiveN1FrameSize
                          PositiveInteger,
                  lapbOperTransmitKWindowSize
                          INTEGER,
                  lapbOperReceiveKWindowSize
                          INTEGER,
                  lapbOperN2RxmitCount
                          INTEGER,
                  lapbOperT1AckTimer
                          PositiveInteger,
                  lapbOperT2AckDelayTimer
                          PositiveInteger,
                  lapbOperT3DisconnectTimer
                          PositiveInteger,
                  lapbOperT4IdleTimer
                          PositiveInteger,
                  lapbOperPortId
                          OBJECT IDENTIFIER,
                  lapbOperProtocolVersionId
                          OBJECT IDENTIFIER
                  }

          lapbOperIndex   OBJECT-TYPE
             SYNTAX       IfIndexType
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The ifIndex value for the LAPB interface."
                  ::= { lapbOperEntry 1 }

          lapbOperStationType     OBJECT-TYPE
                  SYNTAX  INTEGER {
                          dte (1),
                          dce (2),
                          dxe (3)
                          }
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "Identifies the current operating station
                          type of this interface.  A value of dxe (3)
                          indicates XID negotiation has not yet taken
                          place."



<span class="grey">Throop &amp; Baker                                                 [Page 13]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-14" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                  REFERENCE "ISO 7776 <a href="#section-3.1">section 3.1</a>"
                  ::= { lapbOperEntry 2 }

          lapbOperControlField OBJECT-TYPE
                  SYNTAX  INTEGER {
                          modulo8 (1),
                          modulo128 (2)
                          }
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The current operating size of the sequence
                          numbers used to number frames."
                  REFERENCE "ISO 7776 <a href="#section-3.3">section 3.3</a>"
                  ::= { lapbOperEntry 3 }

          lapbOperTransmitN1FrameSize OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The current operating N1 frame size used
                          for the maximum number of bits in a frame
                          this DTE can transmit.  This excludes flags
                          and 0 bits inserted for transparency."
                  REFERENCE "ISO 7776 <a href="#section-5.7.3">section 5.7.3</a>"
                  ::= { lapbOperEntry 4 }

          lapbOperReceiveN1FrameSize OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-only
                  STATUS  mandatory
                  -- See lapbOperTransmitN1FrameSize above
                  DESCRIPTION
                          "The current operating N1 frame size used
                          for the maximum number of bits in a frame
                          the DCE/remote DTE can transmit.  This
                          excludes flags and 0 bits inserted for
                          transparency."
                  ::= { lapbOperEntry 5 }

          lapbOperTransmitKWindowSize OBJECT-TYPE
                  SYNTAX  INTEGER (1..127)
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The current PDU window size this Interface
                          uses to transmit.  This is the maximum



<span class="grey">Throop &amp; Baker                                                 [Page 14]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-15" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                          number of unacknowledged sequenced PDUs that
                          may be outstanding from this DTE at any one
                          time."
                  REFERENCE "ISO 7776 <a href="#section-5.7.4">section 5.7.4</a>"
                  ::= { lapbOperEntry 6 }

          lapbOperReceiveKWindowSize OBJECT-TYPE
                  SYNTAX  INTEGER (1..127)
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The current receive PDU window size for
                          this Interface.  This is the maximum number
                          of unacknowledged sequenced PDUs that may be
                          outstanding from the DCE/remote DTE at any
                          one time."
                  REFERENCE "ISO 7776 <a href="#section-5.7.4">section 5.7.4</a>"
                  ::= { lapbOperEntry 7 }

          lapbOperN2RxmitCount    OBJECT-TYPE
                  SYNTAX  INTEGER (0..65535)
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The current N2 retry counter used for this
                          interface.  This specifies the number of
                          times a PDU will be resent after the T1
                          timer expires without an acknowledgement for
                          the PDU."
                  REFERENCE "ISO 7776 <a href="#section-5.7.2">section 5.7.2</a>"
                  ::= { lapbOperEntry 8 }

          lapbOperT1AckTimer      OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The current T1 timer for this interface.
                          This specifies the maximum time in
                          Milliseconds to wait for acknowledgment of a
                          PDU."
                  REFERENCE "ISO 7776 <a href="#section-5.7.1.1">section 5.7.1.1</a>"
                  ::= { lapbOperEntry 9 }

          lapbOperT2AckDelayTimer         OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-only
                  STATUS  mandatory



<span class="grey">Throop &amp; Baker                                                 [Page 15]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-16" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                  DESCRIPTION
                          "The current T2 timer for this interface.
                          This specifies the maximum time in
                          Milliseconds to wait before sending an
                          acknowledgment for a sequenced PDU.  A value
                          of zero means there will be no delay in
                          acknowledgement generation."
                  REFERENCE "ISO 7776 <a href="#section-5.7.1.2">section 5.7.1.2</a>"
                  ::= { lapbOperEntry 10 }

          lapbOperT3DisconnectTimer OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The current T3 timer for this interface.
                          This specifies the time in Milliseconds to
                          wait before considering the link
                          disconnected.  A value of zero indicates the
                          link will be considered disconnected upon
                          completion of the frame exchange to
                          disconnect the link."
                  REFERENCE "ISO 7776 <a href="#section-5.7.1.3">section 5.7.1.3</a>"
                  ::= { lapbOperEntry 11 }

          lapbOperT4IdleTimer OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The current T4 timer for this interface.
                          This specifies the maximum time in
                          Milliseconds to allow without frames being
                          exchanged on the data link.  A value of
                          2147483647 indicates no idle timer is being
                          kept."
                  REFERENCE "ISO 7776 <a href="#section-5.7.1.4">section 5.7.1.4</a>"
                  ::= { lapbOperEntry 12 }

          lapbOperPortId OBJECT-TYPE
                  SYNTAX  OBJECT IDENTIFIER
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "This object identifies an instance of the
                          index object in the first group of objects
                          in the MIB specific to the physical device
                          or interface used to send and receive



<span class="grey">Throop &amp; Baker                                                 [Page 16]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-17" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                          frames.  If an agent does not support any
                          such objects, it should return nullSpec
                          OBJECT IDENTIFIER {0 0}."
                  ::= { lapbOperEntry 13 }

          lapbOperProtocolVersionId       OBJECT-TYPE
                  SYNTAX  OBJECT IDENTIFIER
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "This object identifies the version of the
                          lapb protocol implemented by this
                          interface."
                  ::= { lapbOperEntry 14 }


          -- ###########################################################
          --                      LAPB    Flow Table
          -- ###########################################################

          -- Support of the lapbFlowTable is mandatory for all
          -- agents of systems that implement LAPB.

          lapbFlowTable OBJECT-TYPE
                  SYNTAX  SEQUENCE OF LapbFlowEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "This table defines the objects recorded by
                          LAPB to provide information about the
                          traffic flow through the interface."
                  ::= { lapb 3 }

          lapbFlowEntry OBJECT-TYPE
                  SYNTAX  LapbFlowEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "The information regarding the effects of
                          flow controls in LAPB."
                   INDEX { lapbFlowIfIndex }
                  ::= { lapbFlowTable 1 }

          LapbFlowEntry ::= SEQUENCE {
                  lapbFlowIfIndex
                          IfIndexType,
                  lapbFlowStateChanges
                          Counter,



<span class="grey">Throop &amp; Baker                                                 [Page 17]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-18" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                  lapbFlowChangeReason
                          INTEGER,
                  lapbFlowCurrentMode
                          INTEGER,
                  lapbFlowBusyDefers
                          Counter,
                  lapbFlowRejOutPkts
                          Counter,
                  lapbFlowRejInPkts
                          Counter,
                  lapbFlowT1Timeouts
                          Counter,
                  lapbFlowFrmrSent
                  OCTET STRING,
                  lapbFlowFrmrReceived
                          OCTET STRING,
                  lapbFlowXidReceived
                          OCTET STRING
                  }

          lapbFlowIfIndex OBJECT-TYPE
                  SYNTAX  IfIndexType
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The ifIndex value for the LAPB Interface."
                  ::= { lapbFlowEntry 1 }

          lapbFlowStateChanges OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of LAPB State Changes, including
                          resets."
                  ::= { lapbFlowEntry 2 }

          lapbFlowChangeReason OBJECT-TYPE
                  SYNTAX  INTEGER {
                          notStarted (1),    -- Initial state
                          abmEntered (2),    -- SABM or UA
                          abmeEntered (3),   -- SABME or UA
                          abmReset (4),      -- SABM in ABM
                          abmeReset (5),     -- SABME in ABME
                          dmReceived (6),    -- DM Response
                          dmSent (7),        -- DM sent
                          discReceived (8),  -- DISC Response
                          discSent (9),      -- DISC Sent



<span class="grey">Throop &amp; Baker                                                 [Page 18]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-19" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                          frmrReceived (10), -- FRMR Received
                          frmrSent (11),     -- FRMR Sent
                          n2Timeout (12),    -- N2 Timer Expired
                          other (13)
                            }
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The reason for the most recent incrementing
                          of lapbFlowStateChanges.  A DM or DISC frame
                          generated to initiate link set-up does not
                          alter this object.  When the MIB-II object
                          ifOperStatus does not have a value of
                          testing, there exists a correlation between
                          this object and ifOperStatus.  IfOperStatus
                          will have a value of up when this object
                          contains:  abmEntered, abmeEntered,
                          abmReset, or abmeReset.  IfOperStatus will
                          have a value of down when this object has a
                          value of notStarted, or dmReceived through
                          n2Timeout.  There is no correlation when
                          this object has the value other."
                  ::= { lapbFlowEntry 3 }

          lapbFlowCurrentMode OBJECT-TYPE
                  SYNTAX  INTEGER {
                          disconnected (1),
                                  -- initial state or DISC received

                          linkSetup (2),
                                  -- SABM sent

                          frameReject (3),
                                  -- Invalid frame received and
                                  -- FRMR sent

                          disconnectRequest (4),
                                  -- DISC sent

                          informationTransfer (5),
                                  -- normal information transfer state
                                  -- SABM(E) sent and UA received, or
                                  -- SABM(E) received and UA sent

                          rejFrameSent (6),
                                  -- invalid NS received and REJ sent

                          waitingAcknowledgement (7),



<span class="grey">Throop &amp; Baker                                                 [Page 19]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-20" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                                  -- T1 expired and RR sent

                          stationBusy (8),
                                  -- RNR sent

                          remoteStationBusy (9),
                                  -- RNR received

                          bothStationsBusy (10),
                                  -- RNR received and RNR sent

                          waitingAckStationBusy (11),
                                  -- T1 expired, RNR sent

                          waitingAckRemoteBusy (12),
                                  -- T1 expired, RNR received

                          waitingAckBothBusy (13),
                                  -- T1 expired, RNR sent,
                                  -- and RNR received

                          rejFrameSentRemoteBusy (14),
                                  -- REJ sent and RNR received

                          xidFrameSent (15),
                                  -- XID frame sent

                          error (16),
                                  -- An error state other than
                                  -- a one defined above

                          other (17)
                                  --  A state not listed above
                            }
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The current condition of the conversation."
                  ::= { lapbFlowEntry 4 }

          lapbFlowBusyDefers OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of times this device was unable
                          to transmit a frame due to a perceived
                          remote busy condition.  Busy conditions can



<span class="grey">Throop &amp; Baker                                                 [Page 20]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-21" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                          result from the receipt of an RNR from the
                          remote device, the lack of valid sequence
                          number space (window saturation), or other
                          conditions."
                  ::= { lapbFlowEntry 5 }

          lapbFlowRejOutPkts OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of REJ or SREJ frames sent by
                          this station."
                  ::= { lapbFlowEntry 6 }

          lapbFlowRejInPkts OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of REJ or SREJ frames received
                          by this station."
                  ::= { lapbFlowEntry 7 }

          lapbFlowT1Timeouts OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of times a re-transmission was
                          effected by the T1 Timer expiring."
                  ::= { lapbFlowEntry 8 }

          lapbFlowFrmrSent OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..7))
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The Information Field of the FRMR most
                          recently sent.  If no FRMR has been sent
                          (the normal case) or the information isn't
                          available, this will be an OCTET STRING of
                          zero length."
                  REFERENCE "ISO 7776 <a href="#section-4.3.9">Section 4.3.9</a>, tables 7 and 8"
                  ::= { lapbFlowEntry 9 }

          lapbFlowFrmrReceived OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..7))



<span class="grey">Throop &amp; Baker                                                 [Page 21]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-22" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The Information Field of the FRMR most
                          recently received.  If no FRMR has been
                          received (the normal case) or the
                          information isn't available, this will be an
                          OCTET STRING of zero length."
                  REFERENCE "ISO 7776 <a href="#section-4.3.9">Section 4.3.9</a>, tables 7 and 8"
                  ::= { lapbFlowEntry 10 }

          lapbFlowXidReceived OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..8206))
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The Information Field of the XID frame most
                          recently received.  If no XID frame has been
                          received, this will be an OCTET STRING of
                          zero length."
                  REFERENCE "ISO 8885"
                  ::= { lapbFlowEntry 11 }


          -- ###########################################################
          --                      LAPB    XID Table
          -- ###########################################################

          -- Support for the lapbXidTable is mandatory for all agents
          -- of systems that have a LAPB implementation using XID
          -- negotiation.  Agents of systems without XID negotiation
          -- support should not implement this table.

          lapbXidTable    OBJECT-TYPE
                  SYNTAX  SEQUENCE OF LapbXidEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "This table defines values to use for XID
                          negotiation that are not found in the
                          lapbAdmnTable.  This table is optional for
                          implementations that don't support XID and
                          mandatory for implementations that do
                          initiate XID negotiation."
                  ::= { lapb 4 }

          lapbXidEntry    OBJECT-TYPE
                  SYNTAX  LapbXidEntry



<span class="grey">Throop &amp; Baker                                                 [Page 22]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-23" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


             ACCESS       not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "XId negotiation parameter values for a
                          specific LAPB."
                  INDEX { lapbXidIndex }
                  ::= { lapbXidTable 1 }


          LapbXidEntry ::= SEQUENCE {
                  lapbXidIndex
                          IfIndexType,
                  lapbXidAdRIdentifier
                          OCTET STRING,
                  lapbXidAdRAddress
                          OCTET STRING,
                  lapbXidParameterUniqueIdentifier
                          OCTET STRING,
                  lapbXidGroupAddress
                          OCTET STRING,
                  lapbXidPortNumber
                          OCTET STRING,
                  lapbXidUserDataSubfield
                          OCTET STRING
                  }

          lapbXidIndex    OBJECT-TYPE
                  SYNTAX  IfIndexType
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The ifIndex value for the LAPB interface."
                  ::= { lapbXidEntry 1 }

          lapbXidAdRIdentifier OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..255))
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The value of the Address Resolution
                          Identifier.  A zero length string indicates
                          no Identifier value has been assigned."
                  REFERENCE "ISO 8885 Table 2, Name: Identifier"
                  DEFVAL { ''h }
                  ::= { lapbXidEntry 2 }

          lapbXidAdRAddress OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..255))



<span class="grey">Throop &amp; Baker                                                 [Page 23]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-24" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The value of the Address Resolution
                          Address.  A zero length string indicates no
                          Address value has been assigned."
                  REFERENCE "ISO 8885 Table 2, Name: Address"
                  DEFVAL { ''h }
                  ::= { lapbXidEntry 3 }

          lapbXidParameterUniqueIdentifier OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..255))
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The value of the parameter unique
                          Identifier.  A zero length string indicates
                          no Unique identifier value has been
                          assigned."
                  REFERENCE "ISO 8885 Table 3, Name: Identifier"
                  DEFVAL { ''h }
                  ::= { lapbXidEntry 4 }

          lapbXidGroupAddress OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..255))
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The value of the parameter Group address.
                          A zero length string indicates no Group
                          address value has been assigned."
                  REFERENCE "ISO 8885 Table 3, Name: Group address"
                  DEFVAL { ''h }
                  ::= { lapbXidEntry 5 }

          lapbXidPortNumber OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..255))
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The port number assigned for this link.  A
                          zero length string indicates no local port
                          number identifier has been assigned."
                  REFERENCE "ISO 8885 Table 3, Name: Port number"
                  DEFVAL { ''h }
                  ::= { lapbXidEntry 6 }

          lapbXidUserDataSubfield OBJECT-TYPE



<span class="grey">Throop &amp; Baker                                                 [Page 24]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-25" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                  SYNTAX  OCTET STRING (SIZE (0..8206))
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "A user data subfield, if any, to be
                          transmitted in an XID frame.  A zero length
                          frame indicates no user data subfield has
                          been assigned.  The octet string should
                          include both the User data identifier and
                          User data field as shown in Figures 1 and
                          4."
                  REFERENCE "ISO 8885 <a href="#section-4.3">section 4.3</a>"
                  DEFVAL { ''h }
                  ::= { lapbXidEntry 7 }


          -- ###########################################################
          --                      LAPB protocol versions
          -- ###########################################################

          lapbProtocolVersion OBJECT IDENTIFIER
                  ::= { lapb 5 }

          lapbProtocolIso7776v1986 OBJECT IDENTIFIER
                  ::= { lapbProtocolVersion 1 }

          lapbProtocolCcittV1980 OBJECT IDENTIFIER
                  ::= { lapbProtocolVersion 2 }

          lapbProtocolCcittV1984 OBJECT IDENTIFIER
                  ::= { lapbProtocolVersion 3 }



          -- The following describes some of the MIB-II interface
          -- objects and their relationship with the objects in this
          -- MIB extension.

          -- ifDescr:  describes the interface.   It should include
          -- identification information for the physical line and a
          -- description of the network.  For connections to PDNs,
          -- it should name the PDN.

          -- ifMtu: the maximum number of octets an upper layer can
          -- pass to this interface as a single frame.

          -- ifSpeed:




<span class="grey">Throop &amp; Baker                                                 [Page 25]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-26" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


          -- ifAdminStatus:

          -- ifOperStatus:

          -- ifLastChange: the last time the state of the interface
          -- changed.  A reset is considered an instantaneous change to
          -- the ndm state and back to abm or abme.  This will be the
          -- last time that lapbFlowChangeReason and lapbFlowChanges
          -- changed.

          -- ifInOctets: contains the number of octets
          -- received from the peer LAPB including FCS.

          -- ifInUcastPkts: contains the number of I-frames delivered
          -- by this interface to a higher layer interface.

          -- ifInDiscards: contains the number of received
          -- frames discarded because of internal conditions
          -- (such as lack of buffering).

          -- ifInErrors: contains the number of Invalid frames received.
          -- This does not have any relationship with the number REJ,
          -- or RNR frames sent or received.

          -- ifInUnknownProtos: contains the number of frames
          -- that were correct but were dropped because they
          -- were inappropriate for the current state.  This
          -- includes an invalid Poll bit, an unknown address,
          -- or other condition such as an RNR when connection
          -- not established.  This also includes the number of
          -- DISC or other frames that were ignored because the
          -- link was not established and this interface was not
          -- configured to perform link setup on that type frame.

          -- ifOutOctets: number of octets sent to peer including
          -- FCS octets.

          -- ifOutUcastPkts: number of I-frames received from
          -- a higher layer for transmission to peer.

          -- ifOutDiscards: number of frames to be sent that were
          -- dropped due to internal conditions such as buffering etc.

          -- ifOutErrors: number of transmissions that failed
          -- due to errors or were considered invalid by the receiver.
          -- This does not have any relationship with the number REJ,
          -- or RNR frames sent or received.




<span class="grey">Throop &amp; Baker                                                 [Page 26]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-27" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


          -- ifOutQLen: number of frames waiting to be transmitted.


          -- This MIB does not provide any support for:
          --      Multilink procedure (MLP) in ISO 7776 <a href="#section-6">section 6</a>
          --      LLC Pbit timer
          --      LLC REJ timer
          --      LLC Busy State Timer 7.8.1.4

          -- ###########################################################

          END

<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>.  Appendix: Revision History</span>

July 30, 1992

The July revision of this document (Editor's Internal Reference 2.10)
incorporated the comments of the SNMP directorate.

      The ifIndexType textual convention was added and used as the type
      for all index objects.

      The enumeration xidDetection of the lapbAdmnStationType was
      changed to dxe to be consistent with other similar enumerations.

      Conformance statements were added at before every table as ASN.1
      comments.

June 12, 1992

   The June 12, 1992 revision of this document (Editor's Internal
   Reference 2.9) incorporated some clarifications and updated the
   status.

      The range on PositiveInteger was changed to start at 0 rather than
      1.

      The syntax of lapbXidIndex was changed to PositiveInteger.

      A value of dxe was added to lapbOperStationType.

      The range of lapbAdmnN2RxmitCount was change to (0..65535).

      The definition of ifInOctets, ifInUcastPkts, ifInErrors,
      ifInUnknownProtos, ifOutOctets, and ifoutUcastPkts was clarified.





<span class="grey">Throop &amp; Baker                                                 [Page 27]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-28" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


May 18, 1992

   The May 18, 1992 revision of this document (Editor's Internal
   Reference  2.8) incorporated the following changes:

      The states of lapbFlowCurrentMode were redefined.

      The default value for lapbAdmnControlField was changed from
      module8 to modulo8.

April 8, 1992

   The April 8, 1992 revision of this document (Editor's Internal
   Reference 2.4) incorporated the following changes:

      All reference comments in the MIB were moved to the REFERENCE
      field of the OBJECT-TYPE macro.

      A type of PositiveInteger was introduced and used for common
      integer values including all timers.  This effectively made the
      maximum value for timers 2147483646 milliseconds.  The type of the
      frame size was changed to positiveInteger.

      The reference to ISO 7776 has been broadened to say the MIB
      descriptions use the terminology of ISO 7776.

      A comment was added to the overview section discussing creation
      and deletion of tables.

      The objects in the lapbParmTable and lapbDefTable were
      redistributed to create a lapbOperTable, a lapbAdmnTable, and a
      lapbXidTable.  The lapbParmTable and lapbDefTable were deleted.
      Objects were included in the Admn table for t3 and t4.

      An object identifier was added to identify the protocol version.

      A DEFVAL clause was added for all writable objects.

      Some more overview text was included.

February 1992

   The February 1992 revision of this document (Editor's Internal
   Reference 1.17) incorporated the following changes:

      The name was changed from HDLC to LAPB. This change was made
      because other flavors of HDLC such as LAPD, SDLC, and raw HDLC
      framing, are different enough that this MIB will not adequately



<span class="grey">Throop &amp; Baker                                                 [Page 28]</span></pre>
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<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


      manage them.

      The Historical Perspective section at the beginning of the
      document has been replaced with a more concise Network Management
      Framework section.

      The name lapbParmKWindowSize was changed to
      lapbParmTransmitKWindowSize and the object
      lapbParmReceiveKWindowSize was added. This change was made because
      <a href="#section-5.7.4">section 5.7.4</a> of ISO 7776 and Table 3 of ISO 8885 have provisions
      for different values for the transmit and receive window size.

      The name lapbParmN1FrameSize was changed to
      lapbParmTransmitN1FrameSize and the object
      lapbParmReceiveN1FrameSize was added. This change was made because
      <a href="#section-5.7.3">section 5.7.3</a> of ISO 7776 and Table 3 of ISO 8886 have provisions
      for different values for the transmit and receive maximum frame
      size.

      The object lapbParmPortIndex was deleted and the description of
      lapbParmPortId was changed.  The object lapbParmPortId now
      identifies an instance of the index object for the MIB of the
      physical device or interface below LAPB.

      The units for the timers were changed to Milliseconds to be
      consistent with ISO 8885; see table 3.

      The objects lapbParamT2AckDelayTimer and
      lapbParamT3DisconnectTimer both allow values of 0 to indicate the
      timer is not being used.

      The object lapbParamT4IdleTimer has a value to indicate timer not
      in use.

      The object lapbFlowXidReceived was added to the flow table.

      The lapbDefTable was added.

      Ranges and sizes were added for all INTEGERs and OCTET STRINGs
      that didn't have them.

October 1991

   The October 1991 revision of this document basically changed the name
   from LAPB to HDLC to make the objects more appropriate for a broader
   range of uses.  A number of minor changes were made to bring the
   objects in line with established conventions.  These changes are as
   follows.



<span class="grey">Throop &amp; Baker                                                 [Page 29]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-30" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


      The enumerated values of hdlcParmStationType were renumbered from
      0 and 1 to 1 and 2.

      The object hdlcFlowBusyDefer was renamed hdlcFlowBusyDefers.

      The object hdlcFlowRejSent was rename hdlcFlowRejOutPkts.

      The object hdlcFlowRejReceived was renamed hdlcFlowRejInPkts.

June 1991

   The June revision of this document incorporated much of the E-mail
   discussion of the first draft. In particular it replaced the
   lapbStatTable (and all contents) with the lapbFlowTable.

April 1991

   The April 24 version of this document was the first release.  At that
   time this document was basically a bunch of objects synthesized from
   various vendor MIBs and a quick reading of ISO 7776 [<a href="#ref-10" title="&quot;Information processing systems - Data communication - High-level data link control procedure - Description of the X.25 LAPB- compatible DTE data link procedures&quot;">10</a>].  On first
   reading it appeared to instrument too many LAPB normal functions and
   too few exceptional conditions.  The lapbStatTable was too long and
   needed to be redone.

<span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>.  Acknowledgements</span>

   This document was produced by the x25mib working group:

                  Fred Baker, ACC
                  Art Berggreen, ACC
                  Frank Bieser
                  Gary Bjerke, Tandem
                  Bill Bowman, HP
                  Christopher Bucci, Datability
                  Charles Carvalho, ACC
                  Jeff Case, Snmp Research
                  Angela Chen, HP
                  Carson Cheung, BNR
                  Tom Daniel, Spider Systems
                  Chuck Davin, MIT
                  Billy Durham, Honeywell
                  Richard Fox, Synoptics
                  Doug Geller, Data General
                  Herve Goguely, LIR Corp
                  Andy Goldthorpe, british-telecom
                  Walter D. Guilarte
                  David Gurevich
                  Steve Huston, Process Software Corporation



<span class="grey">Throop &amp; Baker                                                 [Page 30]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-31" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


                  Jon Infante, ICL
                  Frank Kastenholz, Clearpoint
                  Zbigniew Kielczewski, Eicon
                  Cheryl Krupezak, Georgia Tech
                  Mats Lindstrom, Diab Data AB
                  Andrew Malis, BBN
                  Evan McGinnis, 3Com
                  Gary (G.P.)Mussar, BNR
                  Chandy Nilakantan, 3Com
                  Randy Pafford, Data General
                  Ragnar Paulson, The Software Group Limited
                  Dave Perkins, Synoptics
                  Walter Pinkarschewsky, DEC
                  Karen Quidley, Data General
                  Chris Ranch, Novell
                  Paul S. Rarey, DHL Systems Inc.
                  Jim Roche, Newbridge Research
                  Philippe Roger, LIR Corp.
                  Timon Sloane
                  Mike Shand, DEC
                  Brad Steina, Microcom
                  Bob Stewart, Xyplex
                  Tom Sullivan, Data General
                  Rodney Thayer, Sable Technology Corporation
                  Mark Therieau, Microcom
                  Jane Thorn, Data General
                  Dean Throop, Data General
                  Maurice Turcotte, Racal Datacom
                  Mike Zendels, Data General

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

                  Keith McCloghrie


<span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>.  References</span>

   [<a id="ref-1">1</a>] Rose M., and K. McCloghrie, "Structure and Identification of
       Management Information for TCP/IP-based internets", STD 16, <a href="./rfc1155">RFC</a>
       <a href="./rfc1155">1155</a>, Performance Systems International, Hughes LAN Systems, May
       1990.

   [<a id="ref-2">2</a>] McCloghrie K., and M. Rose, "Management Information Base for
       Network Management of TCP/IP-based internets", <a href="./rfc1156">RFC 1156</a>, Hughes
       LAN Systems, Performance Systems International, May 1990.

   [<a id="ref-3">3</a>] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple



<span class="grey">Throop &amp; Baker                                                 [Page 31]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-32" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


       Network Management Protocol", STD 15, <a href="./rfc1157">RFC 1157</a>, SNMP Research,
       Performance Systems International, Performance Systems
       International, MIT Laboratory for Computer Science, May 1990.

   [<a id="ref-4">4</a>] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
       STD 16, <a href="./rfc1212">RFC 1212</a>, Performance Systems International, Hughes LAN
       Systems, March 1991.

   [<a id="ref-5">5</a>] Rose M., Editor, "Management Information Base for Network
       Management of TCP/IP-based internets: MIB-II", STD 17, <a href="./rfc1213">RFC 1213</a>,
       Performance Systems International, March 1991.

   [<a id="ref-6">6</a>] Information processing systems - Open Systems Interconnection -
       Specification of Abstract Syntax Notation One (ASN.1),
       International Organization for Standardization, International
       Standard 8824, December 1987.

   [<a id="ref-7">7</a>] 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.

   [<a id="ref-8">8</a>] Stewart, B., Editor, "Definitions of Managed Objects for RS-232-
       like Hardware Devices", <a href="./rfc1317">RFC 1317</a>, Xyplex, Inc., April 1992.

   [<a id="ref-9">9</a>] Throop, D., Editor, "SNMP MIB extension for the Packet Layer of
       X.25", <a href="./rfc1382">RFC 1382</a>, Data General Corporation, November 1992.

  [<a id="ref-10">10</a>] "Information processing systems - Data communication - High-level
       data link control procedure - Description of the X.25 LAPB-
       compatible DTE data link procedures", International Organization
       for Standardization, International Standard 7776, December 1986.

  [<a id="ref-11">11</a>] "Information technology - Telecommunications and information
       exchange between systems - High-level data link control (HDLC)
       procedures - General purpose XID frame information field contents
       and format", International Organization for Standardization,
       International Standard 8885.













<span class="grey">Throop &amp; Baker                                                 [Page 32]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-33" ></span>
<span class="grey"><a href="./rfc1381">RFC 1381</a>                     X.25 LAPB MIB                 November 1992</span>


<span class="h2"><a class="selflink" id="section-8" href="#section-8">8</a>.  Security Considerations</span>

   Security issues are not discussed in this memo.

<span class="h2"><a class="selflink" id="section-9" href="#section-9">9</a>.  Authors' Addresses</span>

   Dean D. Throop
   Data General Corporation
   62 Alexander Dr.
   Research Triangle Park, NC 27709

   Phone: (919)248-8421
   EMail: throop@dg-rtp.dg.com


   Fred Baker
   Advanced Computer Communications
   315 Bollay Drive
   Santa Barbara, CA 93101

   Phone: (805) 685-4455
   EMail: fbaker@acc.com

   While the working group has completed discussion of this document,
   comments are still welcome.  Please send comments to the x25mib
   working group at: x25mib@dg-rtp.dg.com

























Throop &amp; Baker                                                 [Page 33]
</pre>