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+Network Working Group                                          D. Throop
+Request for Comments: 1381                      Data General Corporation
+                                                                F. Baker
+                                        Advanced Computer Communications
+                                                           November 1992
+
+
+                    SNMP MIB Extension for X.25 LAPB
+
+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" [9] and the
+   "Definitions of Managed Objects for RS-232-like Hardware Devices"
+   [8], combine to allow management of an X.25 protocol stack.
+
+Table of Contents
+
+   1. The Network Management Framework .......................    2
+   2. Objects ................................................    2
+   2.1 Format of Definitions .................................    3
+   3. Overview ...............................................    3
+   3.1 Informal overview .....................................    3
+   3.2 Textual Conventions ...................................    4
+   3.3 Formal overview .......................................    4
+   3.4 Tables ................................................    5
+   3.5 Traps .................................................    6
+   4. Object Definitions .....................................    6
+   5. Appendix: Revision History .............................   27
+      July 30, 1992 ..........................................   27
+      June 12, 1992 ..........................................   27
+      May 18, 1992 ...........................................   28
+      April 8, 1992 ..........................................   28
+      February 1992 ..........................................   28
+      October 1991 ...........................................   29
+      June 1991 ..............................................   30
+      April 1991 .............................................   30
+
+
+
+Throop & Baker                                                  [Page 1]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+   6. Acknowledgements .......................................   30
+   7. References .............................................   31
+   8. Security Considerations ................................   33
+   9. Authors' Addresses .....................................   33
+
+1.  The Network Management Framework
+
+   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 [1]. 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" [4],
+   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 RFC 1156 [2] "Management Information Base for Network
+   Management of TCP/IP-based internets". STD 17/RFC 1213 [5] defines
+   MIB-II, an evolution of MIB-I with changes to incorporate
+   implementation experience and new operational requirements.
+
+   STD 15/RFC 1157 [3] 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.
+
+2.  Objects
+
+   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) [6] defined in the SMI [1].
+   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 [6] provides
+
+
+
+Throop & Baker                                                  [Page 2]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+   the primitives used for this purpose.  The SMI [1] 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 [7],
+   for purposes of dealing with the SNMP protocol.
+
+2.1.  Format of Definitions
+
+   Section 4 contains the specification of all object types defined in
+   this MIB module. The object definitions use the conventions given in
+   the SMI [1] as amended by the concise MIB definitions [4].
+
+3.  Overview
+
+3.1.  Informal overview
+
+   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 [9].  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
+
+
+
+Throop & Baker                                                  [Page 3]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+   of type LAPB. Different LAPB interfaces can also be differentiated by
+   matching the values of ifIndex with lapbAdmnIndex.
+
+3.2.  Textual Conventions
+
+   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
+
+3.3.  Formal overview
+
+   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 [5] of
+
+                lapb(16).
+
+   For these interfaces, the value of the ifSpecific variable in the
+   MIB-II [5] 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 [5] 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 [10]
+   and ISO 8885 [11]. 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
+
+
+
+Throop & Baker                                                  [Page 4]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+   to a LAPB configured as either a DCE or a DTE.
+
+   To the extent that some attributes defined in the Internet standard
+   MIB [5] 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.
+
+3.4.  Tables
+
+   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.
+
+
+
+
+
+Throop & Baker                                                  [Page 5]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+3.5.  Traps
+
+   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.
+
+4.  Object Definitions
+
+
+          RFC1381-MIB DEFINITIONS ::= BEGIN
+
+          IMPORTS
+                  Counter
+                          FROM RFC1155-SMI
+                  transmission
+                          FROM RFC1213-MIB
+                  OBJECT-TYPE
+                          FROM RFC-1212;
+
+
+                          --  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
+
+
+
+Throop & Baker                                                  [Page 6]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                  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
+
+
+
+Throop & Baker                                                  [Page 7]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                          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 section 3.1"
+                  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 }
+
+
+
+Throop & Baker                                                  [Page 8]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                  ::= { 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
+
+
+
+Throop & Baker                                                  [Page 9]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                          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,
+
+
+
+Throop & Baker                                                 [Page 10]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                          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 section 5.7.1.3"
+                  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 section 5.7.1.4"
+                  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 }
+
+
+
+Throop & Baker                                                 [Page 11]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+          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
+
+
+
+Throop & Baker                                                 [Page 12]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                          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."
+
+
+
+Throop & Baker                                                 [Page 13]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                  REFERENCE "ISO 7776 section 3.1"
+                  ::= { 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 section 3.3"
+                  ::= { 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 section 5.7.3"
+                  ::= { 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
+
+
+
+Throop & Baker                                                 [Page 14]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                          number of unacknowledged sequenced PDUs that
+                          may be outstanding from this DTE at any one
+                          time."
+                  REFERENCE "ISO 7776 section 5.7.4"
+                  ::= { 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 section 5.7.4"
+                  ::= { 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 section 5.7.2"
+                  ::= { 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 section 5.7.1.1"
+                  ::= { lapbOperEntry 9 }
+
+          lapbOperT2AckDelayTimer         OBJECT-TYPE
+                  SYNTAX  PositiveInteger
+                  ACCESS  read-only
+                  STATUS  mandatory
+
+
+
+Throop & Baker                                                 [Page 15]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                  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 section 5.7.1.2"
+                  ::= { 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 section 5.7.1.3"
+                  ::= { 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 section 5.7.1.4"
+                  ::= { 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
+
+
+
+Throop & Baker                                                 [Page 16]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                          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,
+
+
+
+Throop & Baker                                                 [Page 17]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                  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
+
+
+
+Throop & Baker                                                 [Page 18]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                          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),
+
+
+
+Throop & Baker                                                 [Page 19]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                                  -- 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
+
+
+
+Throop & Baker                                                 [Page 20]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                          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 Section 4.3.9, tables 7 and 8"
+                  ::= { lapbFlowEntry 9 }
+
+          lapbFlowFrmrReceived OBJECT-TYPE
+                  SYNTAX  OCTET STRING (SIZE (0..7))
+
+
+
+Throop & Baker                                                 [Page 21]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                  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 Section 4.3.9, 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
+
+
+
+Throop & Baker                                                 [Page 22]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+             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))
+
+
+
+Throop & Baker                                                 [Page 23]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                  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
+
+
+
+Throop & Baker                                                 [Page 24]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                  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 section 4.3"
+                  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:
+
+
+
+
+Throop & Baker                                                 [Page 25]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+          -- 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.
+
+
+
+
+Throop & Baker                                                 [Page 26]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+          -- ifOutQLen: number of frames waiting to be transmitted.
+
+
+          -- This MIB does not provide any support for:
+          --      Multilink procedure (MLP) in ISO 7776 section 6
+          --      LLC Pbit timer
+          --      LLC REJ timer
+          --      LLC Busy State Timer 7.8.1.4
+
+          -- ###########################################################
+
+          END
+
+5.  Appendix: Revision History
+
+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.
+
+
+
+
+
+Throop & Baker                                                 [Page 27]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+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
+
+
+
+Throop & Baker                                                 [Page 28]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+      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
+      section 5.7.4 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
+      section 5.7.3 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.
+
+
+
+Throop & Baker                                                 [Page 29]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+      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 [10].  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.
+
+6.  Acknowledgements
+
+   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
+
+
+
+Throop & Baker                                                 [Page 30]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+                  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
+
+
+7.  References
+
+   [1] Rose M., and K. McCloghrie, "Structure and Identification of
+       Management Information for TCP/IP-based internets", STD 16, RFC
+       1155, Performance Systems International, Hughes LAN Systems, May
+       1990.
+
+   [2] 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.
+
+   [3] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
+
+
+
+Throop & Baker                                                 [Page 31]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+       Network Management Protocol", STD 15, RFC 1157, SNMP Research,
+       Performance Systems International, Performance Systems
+       International, MIT Laboratory for Computer Science, May 1990.
+
+   [4] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
+       STD 16, RFC 1212, Performance Systems International, Hughes LAN
+       Systems, March 1991.
+
+   [5] Rose M., Editor, "Management Information Base for Network
+       Management of TCP/IP-based internets: MIB-II", STD 17, RFC 1213,
+       Performance Systems International, March 1991.
+
+   [6] Information processing systems - Open Systems Interconnection -
+       Specification of Abstract Syntax Notation One (ASN.1),
+       International Organization for Standardization, International
+       Standard 8824, December 1987.
+
+   [7] 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.
+
+   [8] Stewart, B., Editor, "Definitions of Managed Objects for RS-232-
+       like Hardware Devices", RFC 1317, Xyplex, Inc., April 1992.
+
+   [9] Throop, D., Editor, "SNMP MIB extension for the Packet Layer of
+       X.25", RFC 1382, Data General Corporation, November 1992.
+
+  [10] "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.
+
+  [11] "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.
+
+
+
+
+
+
+
+
+
+
+
+
+
+Throop & Baker                                                 [Page 32]
+
+RFC 1381                     X.25 LAPB MIB                 November 1992
+
+
+8.  Security Considerations
+
+   Security issues are not discussed in this memo.
+
+9.  Authors' Addresses
+
+   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 & Baker                                                 [Page 33]
+
\ No newline at end of file