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RFC 1471 - The Definitions of Managed Objects for the Link Contr


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Network Working Group                                      F. Kastenholz
Request for Comments: 1471                            FTP Software, Inc.
                                                               June 1993

                 The Definitions of Managed Objects for
                      the Link Control Protocol of
                      the Point-to-Point Protocol

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 describes managed objects used for managing the
   Link Control Protocol and Link Quality Monitoring on subnetwork
   interfaces that use the family of Point-to-Point Protocols [8, 9, 10,
   11, & 12].

Table of Contents

   1. The Network Management Framework ......................    2
   2. Objects ...............................................    2
   2.1 Format of Definitions ................................    2
   3. Overview ..............................................    2
   3.1 Object Selection Criteria ............................    2
   3.2 Structure of the PPP .................................    3
   3.3 MIB Groups ...........................................    4
   3.4 Relationship to Interface and Interface Extensions
       Groups ...............................................    5
   4. Definitions ...........................................    6
   4.1 PPP Link Group .......................................    7
   4.2 PPP LQR Group ........................................   16
   4.3 PPP LQR Extensions Group .............................   21
   4.4 PPP Tests ............................................   22
   4.4.1 PPP Echo Test ......................................   22
   4.4.2 PPP Discard Test ...................................   23
   5. Acknowledgements ......................................   23
   6. Security Considerations ...............................   23
   7. References ............................................   24
   8. Author's Address ......................................   25

1.  The Network Management Framework

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

      STD 16/RFC 1155 which defines the SMI, the mechanisms used for
      describing and naming objects for the purpose of management.  STD
      16/RFC 1212 defines a more concise description mechanism, which is
      wholly consistent with the SMI.

      STD 17/RFC 1213 which defines MIB-II, the core set of managed
      objects for the Internet suite of protocols.

      STD 15/RFC 1157 which defines the SNMP, the protocol used for
      network access to managed objects.

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

2.  Objects

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the subset of Abstract Syntax Notation One (ASN.1) [3]
   defined in the SMI.  In particular, each object type is named by an
   OBJECT IDENTIFIER, an administratively assigned name.  The object
   type together with an object instance serves to uniquely identify a
   specific instantiation of the object.  For human convenience, we
   often use a textual string, termed the descriptor, to refer to the
   object type.

2.1.  Format of Definitions

   Section 4 contains the specification of all object types contained in
   this MIB module.  The object types are defined using the conventions
   defined in the SMI, as amended by the extensions specified in [5,6].

3.  Overview

3.1.  Object Selection Criteria

   To be consistent with IAB directives and good engineering practice,
   an explicit attempt was made to keep this MIB as simple as possible.
   This was accomplished by applying the following criteria to objects
   proposed for inclusion:

      (1)  Require objects be essential for either fault or
           configuration management.  In particular, objects for

           which the sole purpose was to debug implementations were
           explicitly excluded from the MIB.

      (2)  Consider evidence of current use and/or utility.

      (3)  Limit the total number of objects.

      (4)  Exclude objects which are simply derivable from others in
           this or other MIBs.

3.2.  Structure of the PPP

   This section describes the basic model of PPP used in developing the
   PPP MIB. This information should be useful to the implementor in
   understanding some of the basic design decisions of the MIB.

   The PPP is not one single protocol but a large family of protocols.
   Each of these is, in itself, a fairly complex protocol.  The PPP
   protocols may be divided into three rough categories:

   Control Protocols
      The Control Protocols are used to control the operation of the
      PPP. The Control Protocols include the Link Control Protocol
      (LCP), the Password Authentication Protocol (PAP), the Link
      Quality Report (LQR), and the Challenge Handshake Authentication
      Protocol (CHAP).

   Network Protocols
      The Network Protocols are used to move the network traffic over
      the PPP interface.  A Network Protocol encapsulates the datagrams
      of a specific higher-layer protocol that is using the PPP as a
      data link.  Note that within the context of PPP, the term "Network
      Protocol" does not imply an OSI Layer-3 protocol; for instance,
      there is a Bridging network protocol.

   Network Control Protocols (NCPs)
      The NCPs are used to control the operation of the Network
      Protocols. Generally, each Network Protocol has its own Network
      Control Protocol; thus, the IP Network Protocol has its IP Control
      Protocol, the Bridging Network Protocol has its Bridging Network
      Control Protocol and so on.

   This document specifies the objects used in managing one of these
   protocols, namely the Link Control Protocol and Link Quality
   Monitoring Protocol.

3.3.  MIB Groups

   Objects in this MIB are arranged into several MIB groups.  Each group
   is organized as a set of related objects.

   These groups are the basic unit of conformance: if the semantics of a
   group are applicable to an implementation then all objects in the
   group must be implemented.

   The PPP MIB is organized into several MIB Groups, including, but not
   limited to, the following groups:

          o The PPP Link Group
          o The PPP LQR Group
          o The PPP LQR Extensions Group
          o The PPP IP Group
          o The PPP Bridge Group
          o The PPP Security Group

   This document specifies the following groups:

   The PPP Link Group
      This group represents the lowest "level" of the PPP protocol.

      This group contains two tables, one containing status information
      and the other configuration information.  The configuration table
      is split off of the status so that it may be placed in a separate
      MIB View for security purposes.

      Implementation of this group is mandatory for all PPP
      implementations.

   The PPP LQR Group
      This group provides the basic MIB variables that apply to the PPP
      LQR Protocol.  This group provides MIB access to the information
      required for LQR processing. This group contains two tables, one
      containing status information and the other configuration
      information.  The configuration table is split off of the status
      so that it may be placed in a separate MIB View for security
      purposes.

      Implementation of the PPP LQR Group is mandatory for all PPP
      implementations that implement LQR.

   The PPP LQR Extensions Group
      The PPP LQR Extensions group contains the most recently received
      LQR packet, as well as the "save" fields that are "logically
      appended" [12] to received LQR packets.  This is done in order to

      facilitate external implementations of the Link Quality Monitoring
      policies.

      It is not practical to examine the relevant MIB objects which are
      used to generate LQR packets since LQR policies may require
      synchronization of the values of all data used to determine Link
      Quality; i.e., the values of the relevant counters must all be
      taken at the same instant in time.  Thus, by recording the last
      received LQR packet, a synchronized record of the relevant data is
      available.

      As this information may not be efficiently maintained on all PPP
      implementations, implementation of this group is optional.

3.4.  Relationship to Interface and Interface Extensions
      Groups

   The PPP Mib is a medium-specific extension to the standard MIB-2
   interface group [2] and to the Interface Extensions MIB [7].  This
   section discusses certain components of these groups when the
   interface is a PPP interface.

   The PPP interface represents a single interface in the sense used in
   [2] and thus has a single entry in the ifTable.

   Furthermore, the PPP interface may be operating over a lower layer
   hardware interface (such as an RS-232 port).  It is important to
   capture the relationship between the PPP interface and the lower-
   layer interface over which it operates.  This MIB presumes that the
   lower-layer interface has an ifEntry associated with it.  The lower-
   layer ifEntry is identified via the pppLinkStatusPhysicalIndex
   object, which contains the value of ifIndex for the lower-layer
   ifEntry.

   For example, suppose that you run PPP over a RS-232 port.  This would
   use two entries in the ifTable.  Let's suppose that entry number 123
   is for the PPP "interface" and entry number 987 is for the RS-232
   port.  So, ifSpecific.123 would contain the ppp OBJECT IDENTIFIER,
   pppLinkStatusPhysicalIndex.123 would contain 987, and ifSpecific.987
   would contain the rs_232 OBJECT IDENTIFIER (or whatever it is).

   All PPP packets are defined in [8] as being broadcast packets.  Thus,
   the packets are counted as non-unicast packets in the ifTable
   (ifInNUcastPkts and ifOutNUCastPkts) and as broadcasts in the
   ifExtnsTable (ifExtnsBroadcastsReceivedOks and
   ifExtnsBroadcastsTransmittedOks).

   ifSpecific
      Contains the OBJECT IDENTIFIER ppp.

   ifAdminStatus
      Setting this object to up will inject an administrative open event
      into the LCP's finite state machine.  Setting this object to down
      will inject an administrative close event into the LCP's finite
      state machine.

      The use of the testing value is beyond the scope of this document.

   ifOperStatus
      Represents the state of the LCP Finite State Machine.  If the
      Finite State Machine is in the Opened state then the value of
      ifOperStatus is up, otherwise the value of ifOperStatus is down.

      The meaning of the testing value is beyond the scope of this
      document.

   Per the SNMP Protocol Specification [13], the linkUp and linkDown
   traps apply to the PPP Protocol entity.  When the LCP's Finite State
   Machine attains the Opened state, a linkUp trap should be sent. When
   the Finite State Machine leaves the Opened state, a linkDown trap
   should be sent.

   Some tests for the link are defined in this document.  Execution of
   these tests does not place the link's ifOperStatus in the testing
   state as these tests do not prevent normal data transmission from
   occuring over the link.

4.  Definitions

          PPP-LCP-MIB DEFINITIONS ::= BEGIN

          IMPORTS
               Counter
                    FROM RFC1155-SMI
               ifIndex, transmission
                    FROM RFC1213-MIB
               OBJECT-TYPE
                    FROM RFC-1212;

               --  PPP MIB

               ppp  OBJECT IDENTIFIER ::= { transmission 23 }

               pppLcp OBJECT IDENTIFIER ::= { ppp 1 }

               -- The individual groups within the PPP-LCP-MIB

               pppLink      OBJECT IDENTIFIER ::= { pppLcp 1 }
               pppLqr       OBJECT IDENTIFIER ::= { pppLcp 2 }
               pppTests     OBJECT IDENTIFIER ::= { pppLcp 3 }

          -- 4.1.  PPP Link Group

          --
          -- The PPP Link Group. Implementation of this
          -- group is mandatory for all PPP entities.
          --

          -- The following object reflect the values of the option
          -- parameters used in the PPP Link Control Protocol
          --   pppLinkStatusLocalMRU
          --   pppLinkStatusRemoteMRU
          --   pppLinkStatusLocalToPeerACCMap
          --   pppLinkStatusPeerToLocalACCMap
          --   pppLinkStatusLocalToRemoteProtocolCompression
          --   pppLinkStatusRemoteToLocalProtocolCompression
          --   pppLinkStatusLocalToRemoteACCompression
          --   pppLinkStatusRemoteToLocalACCompression
          --   pppLinkStatusTransmitFcsSize
          --   pppLinkStatusReceiveFcsSize
          --
          -- These values are not available until after the PPP Option
          -- negotiation has completed, which is indicated by the link
          -- reaching the open state (i.e., ifOperStatus is set to
          -- up).
          --
          -- Therefore, when ifOperStatus is not up
          -- the contents of these objects is undefined. The value
          -- returned when accessing the objects is an implementation
          -- dependent issue.

          pppLinkStatusTable   OBJECT-TYPE
               SYNTAX    SEQUENCE OF PppLinkStatusEntry
               ACCESS    not-accessible
               STATUS    mandatory
               DESCRIPTION
                         "A table containing PPP-link specific variables
                         for this PPP implementation."
               ::= { pppLink 1 }

          pppLinkStatusEntry   OBJECT-TYPE
               SYNTAX    PppLinkStatusEntry
               ACCESS    not-accessible
               STATUS    mandatory
               DESCRIPTION
                         "Management information about a particular PPP
                         Link."
               INDEX     { ifIndex }
               ::= { pppLinkStatusTable 1 }

          PppLinkStatusEntry ::= SEQUENCE {
               pppLinkStatusPhysicalIndex
                    INTEGER,
               pppLinkStatusBadAddresses
                    Counter,
               pppLinkStatusBadControls
                    Counter,
               pppLinkStatusPacketTooLongs
                    Counter,
               pppLinkStatusBadFCSs
                    Counter,
               pppLinkStatusLocalMRU
                    INTEGER,
               pppLinkStatusRemoteMRU
                    INTEGER,
               pppLinkStatusLocalToPeerACCMap
                    OCTET STRING,
               pppLinkStatusPeerToLocalACCMap
                    OCTET STRING,
               pppLinkStatusLocalToRemoteProtocolCompression
                    INTEGER,
               pppLinkStatusRemoteToLocalProtocolCompression
                    INTEGER,
               pppLinkStatusLocalToRemoteACCompression
                    INTEGER,
               pppLinkStatusRemoteToLocalACCompression
                    INTEGER,
               pppLinkStatusTransmitFcsSize
                    INTEGER,
               pppLinkStatusReceiveFcsSize
                    INTEGER
               }
          pppLinkStatusPhysicalIndex   OBJECT-TYPE
               SYNTAX    INTEGER(0..2147483647)
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION

                         "The value of ifIndex that identifies the
                         lower-level interface over which this PPP Link
                         is operating. This interface would usually be
                         an HDLC or RS-232 type of interface. If there
                         is no lower-layer interface element, or there
                         is no ifEntry for the element, or the element
                         can not be identified, then the value of this
                         object is 0.  For example, suppose that PPP is
                         operating over a serial port. This would use
                         two entries in the ifTable. The PPP could be
                         running over `interface' number 123 and the
                         serial port could be running over `interface'
                         number 987.  Therefore, ifSpecific.123 would
                         contain the OBJECT IDENTIFIER ppp
                         pppLinkStatusPhysicalIndex.123 would contain
                         987, and ifSpecific.987 would contain the
                         OBJECT IDENTIFIER for the serial-port's media-
                         specific MIB."
               ::= { pppLinkStatusEntry 1 }

          pppLinkStatusBadAddresses   OBJECT-TYPE
               SYNTAX    Counter
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The number of packets received with an
                         incorrect Address Field. This counter is a
                         component of the ifInErrors variable that is
                         associated with the interface that represents
                         this PPP Link."
               REFERENCE
                         "Section 3.1, Address Field, of RFC1331."
               ::= { pppLinkStatusEntry 2 }

          pppLinkStatusBadControls   OBJECT-TYPE
               SYNTAX    Counter
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The number of packets received on this link
                         with an incorrect Control Field. This counter
                         is a component of the ifInErrors variable that
                         is associated with the interface that
                         represents this PPP Link."
               REFERENCE
                         "Section 3.1, Control Field, of RFC1331."

               ::= { pppLinkStatusEntry 3 }

          pppLinkStatusPacketTooLongs   OBJECT-TYPE
               SYNTAX    Counter
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The number of received packets that have been
                         discarded because their length exceeded the
                         MRU. This counter is a component of the
                         ifInErrors variable that is associated with the
                         interface that represents this PPP Link. NOTE,
                         packets which are longer than the MRU but which
                         are successfully received and processed are NOT
                         included in this count."
               ::= { pppLinkStatusEntry 4 }

          pppLinkStatusBadFCSs   OBJECT-TYPE
               SYNTAX    Counter
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The number of received packets that have been
                         discarded due to having an incorrect FCS. This
                         counter is a component of the ifInErrors
                         variable that is associated with the interface
                         that represents this PPP Link."
               ::= { pppLinkStatusEntry 5 }

          pppLinkStatusLocalMRU   OBJECT-TYPE
               SYNTAX    INTEGER(1..2147483648)
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The current value of the MRU for the local PPP
                         Entity. This value is the MRU that the remote
                         entity is using when sending packets to the
                         local PPP entity. The value of this object is
                         meaningful only when the link has reached the
                         open state (ifOperStatus is up)."
               ::= { pppLinkStatusEntry 6 }

          pppLinkStatusRemoteMRU   OBJECT-TYPE
               SYNTAX    INTEGER(1..2147483648)

               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The current value of the MRU for the remote
                         PPP Entity. This value is the MRU that the
                         local entity is using when sending packets to
                         the remote PPP entity. The value of this object
                         is meaningful only when the link has reached
                         the open state (ifOperStatus is up)."
               ::= { pppLinkStatusEntry 7 }

          pppLinkStatusLocalToPeerACCMap   OBJECT-TYPE
               SYNTAX    OCTET STRING (SIZE (4))
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The current value of the ACC Map used for
                         sending packets from the local PPP entity to
                         the remote PPP entity. The value of this object
                         is meaningful only when the link has reached
                         the open state (ifOperStatus is up)."
               ::= { pppLinkStatusEntry 8 }

          pppLinkStatusPeerToLocalACCMap   OBJECT-TYPE
               SYNTAX    OCTET STRING (SIZE (4))
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The ACC Map used by the remote PPP entity when
                         transmitting packets to the local PPP entity.
                         The value of this object is meaningful only
                         when the link has reached the open state
                         (ifOperStatus is up)."
               ::= { pppLinkStatusEntry 9 }

          pppLinkStatusLocalToRemoteProtocolCompression
               OBJECT-TYPE
               SYNTAX    INTEGER {
                         enabled(1),
                         disabled(2)
                    }
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "Indicates whether the local PPP entity will

                         use Protocol Compression when transmitting
                         packets to the remote PPP entity. The value of
                         this object is meaningful only when the link
                         has reached the open state (ifOperStatus is
                         up)."
               ::= { pppLinkStatusEntry 10 }

          pppLinkStatusRemoteToLocalProtocolCompression
               OBJECT-TYPE
               SYNTAX    INTEGER {
                         enabled(1),
                         disabled(2)
                    }
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "Indicates whether the remote PPP entity will
                         use Protocol Compression when transmitting
                         packets to the local PPP entity. The value of
                         this object is meaningful only when the link
                         has reached the open state (ifOperStatus is
                         up)."
               ::= { pppLinkStatusEntry 11 }

          pppLinkStatusLocalToRemoteACCompression   OBJECT-TYPE
               SYNTAX    INTEGER {
                         enabled(1),
                         disabled(2)
                    }
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "Indicates whether the local PPP entity will
                         use Address and Control Compression when
                         transmitting packets to the remote PPP entity.
                         The value of this object is meaningful only
                         when the link has reached the open state
                         (ifOperStatus is up)."
               ::= { pppLinkStatusEntry 12 }

          pppLinkStatusRemoteToLocalACCompression   OBJECT-TYPE
               SYNTAX    INTEGER {
                         enabled(1),
                         disabled(2)
                    }

               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "Indicates whether the remote PPP entity will
                         use Address and Control Compression when
                         transmitting packets to the local PPP entity.
                         The value of this object is meaningful only
                         when the link has reached the open state
                         (ifOperStatus is up)."
               ::= { pppLinkStatusEntry 13 }

          pppLinkStatusTransmitFcsSize   OBJECT-TYPE
               SYNTAX    INTEGER (0..128)
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The size of the Frame Check Sequence (FCS) in
                         bits that the local node will generate when
                         sending packets to the remote node. The value
                         of this object is meaningful only when the link
                         has reached the open state (ifOperStatus is
                         up)."
               ::= { pppLinkStatusEntry 14 }

          pppLinkStatusReceiveFcsSize   OBJECT-TYPE
               SYNTAX    INTEGER (0..128)
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The size of the Frame Check Sequence (FCS) in
                         bits that the remote node will generate when
                         sending packets to the local node. The value of
                         this object is meaningful only when the link
                         has reached the open state (ifOperStatus is
                         up)."
               ::= { pppLinkStatusEntry 15 }

          pppLinkConfigTable   OBJECT-TYPE
               SYNTAX    SEQUENCE OF PppLinkConfigEntry
               ACCESS    not-accessible
               STATUS    mandatory
               DESCRIPTION
                         "A table containing the LCP configuration
                         parameters for this PPP Link. These variables
                         represent the initial configuration of the PPP

                         Link. The actual values of the parameters may
                         be changed when the link is brought up via the
                         LCP options negotiation mechanism."
               ::= { pppLink 2 }

          pppLinkConfigEntry   OBJECT-TYPE
               SYNTAX    PppLinkConfigEntry
               ACCESS    not-accessible
               STATUS    mandatory
               DESCRIPTION
                         "Configuration information about a particular
                         PPP Link."
               INDEX     { ifIndex }
               ::= { pppLinkConfigTable 1 }

          PppLinkConfigEntry ::= SEQUENCE {
               pppLinkConfigInitialMRU
                    INTEGER,
               pppLinkConfigReceiveACCMap
                    OCTET STRING,
               pppLinkConfigTransmitACCMap
                    OCTET STRING,
               pppLinkConfigMagicNumber
                    INTEGER,
               pppLinkConfigFcsSize
                    INTEGER
               }

          pppLinkConfigInitialMRU   OBJECT-TYPE
               SYNTAX    INTEGER(0..2147483647)
               ACCESS    read-write
               STATUS    mandatory
               DESCRIPTION
                         "The initial Maximum Receive Unit (MRU) that
                         the local PPP entity will advertise to the
                         remote entity. If the value of this variable is
                         0 then the local PPP entity will not advertise
                         any MRU to the remote entity and the default
                         MRU will be assumed. Changing this object will
                         have effect when the link is next restarted."
               REFERENCE
                         "Section 7.2, Maximum Receive Unit of RFC1331."
               DEFVAL    { 1500 }
               ::= { pppLinkConfigEntry 1 }

          pppLinkConfigReceiveACCMap   OBJECT-TYPE
               SYNTAX    OCTET STRING (SIZE (4))
               ACCESS    read-write
               STATUS    mandatory
               DESCRIPTION
                         "The Asynchronous-Control-Character-Map (ACC)
                         that the local PPP entity requires for use on
                         its receive side. In effect, this is the ACC
                         Map that is required in order to ensure that
                         the local modem will successfully receive all
                         characters. The actual ACC map used on the
                         receive side of the link will be a combination
                         of the local node's pppLinkConfigReceiveACCMap
                         and the remote node's
                         pppLinkConfigTransmitACCMap. Changing this
                         object will have effect when the link is next
                         restarted."
               REFERENCE
                         "Section 7.3, page 4, Async-Control-Character-
                         Map of RFC1331."
               DEFVAL    { 'ffffffff'h }
               ::= { pppLinkConfigEntry 2 }

          pppLinkConfigTransmitACCMap   OBJECT-TYPE
               SYNTAX    OCTET STRING (SIZE (4))
               ACCESS    read-write
               STATUS    mandatory
               DESCRIPTION
                         "The Asynchronous-Control-Character-Map (ACC)
                         that the local PPP entity requires for use on
                         its transmit side. In effect, this is the ACC
                         Map that is required in order to ensure that
                         all characters can be successfully transmitted
                         through the local modem.  The actual ACC map
                         used on the transmit side of the link will be a
                         combination of the local node's
                         pppLinkConfigTransmitACCMap and the remote
                         node's pppLinkConfigReceiveACCMap. Changing
                         this object will have effect when the link is
                         next restarted."
               REFERENCE
                         "Section 7.3, page 4, Async-Control-Character-
                         Map of RFC1331."
               DEFVAL    { 'ffffffff'h }
               ::= { pppLinkConfigEntry 3 }

          pppLinkConfigMagicNumber   OBJECT-TYPE
               SYNTAX    INTEGER {false (1), true (2)}
               ACCESS    read-write
               STATUS    mandatory
               DESCRIPTION
                         "If true(2) then the local node will attempt to
                         perform Magic Number negotiation with the
                         remote node. If false(1) then this negotiation
                         is not performed. In any event, the local node
                         will comply with any magic number negotiations
                         attempted by the remote node, per the PPP
                         specification. Changing this object will have
                         effect when the link is next restarted."
               REFERENCE
                         "Section 7.6, Magic Number, of RFC1331."
               DEFVAL    { false }
               ::= { pppLinkConfigEntry 4 }

          pppLinkConfigFcsSize   OBJECT-TYPE
               SYNTAX    INTEGER (0..128)
               ACCESS    read-write
               STATUS    mandatory
               DESCRIPTION
                         "The size of the FCS, in bits, the local node
                         will attempt to negotiate for use with the
                         remote node. Regardless of the value of this
                         object, the local node will comply with any FCS
                         size negotiations initiated by the remote node,
                         per the PPP specification. Changing this object
                         will have effect when the link is next
                         restarted."
               DEFVAL    { 16 }
               ::= { pppLinkConfigEntry 5 }

          -- 4.2.  PPP LQR Group

               --
               -- The PPP LQR Group.
               -- Implementation of this group is mandatory for all
               -- PPP implementations that implement LQR.
               --

          pppLqrTable   OBJECT-TYPE
               SYNTAX    SEQUENCE OF PppLqrEntry
               ACCESS    not-accessible

               STATUS    mandatory
               DESCRIPTION
                         "Table containing the LQR parameters and
                         statistics for the local PPP entity."
               ::= { pppLqr 1 }

          pppLqrEntry   OBJECT-TYPE
               SYNTAX    PppLqrEntry
               ACCESS    not-accessible
               STATUS    mandatory
               DESCRIPTION
                         "LQR information for a particular PPP link. A
                         PPP link will have an entry in this table if
                         and only if LQR Quality Monitoring has been
                         successfully negotiated for said link."
               INDEX     { ifIndex }
               ::= { pppLqrTable 1 }

          PppLqrEntry ::= SEQUENCE {
               pppLqrQuality
                    INTEGER,
               pppLqrInGoodOctets
                    Counter,
               pppLqrLocalPeriod
                    INTEGER,
               pppLqrRemotePeriod
                    INTEGER,
               pppLqrOutLQRs
                    Counter,
               pppLqrInLQRs
                    Counter
          }

          pppLqrQuality   OBJECT-TYPE
               SYNTAX    INTEGER {
                         good(1),
                         bad(2),
                         not-determined(3)
                    }
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The current quality of the link as declared by
                         the local PPP entity's Link-Quality Management
                         modules. No effort is made to define good or
                         bad, nor the policy used to determine it. The

                         not-determined value indicates that the entity
                         does not actually evaluate the link's quality.
                         This value is used to disambiguate the
                         `determined to be good' case from the `no
                         determination made and presumed to be good'
                         case."
               ::= { pppLqrEntry 1 }

          pppLqrInGoodOctets   OBJECT-TYPE
               SYNTAX    Counter
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The LQR InGoodOctets counter for this link."
               REFERENCE
                         "Section 2.2, Counters, of RFC1333."
               ::= { pppLqrEntry 2 }

          pppLqrLocalPeriod   OBJECT-TYPE
               SYNTAX    INTEGER(1..2147483648)
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The LQR reporting period, in hundredths of a
                         second that is in effect for the local PPP
                         entity."
               REFERENCE
                         "Section 2.5, Configuration Option Format, of
                         RFC1333."
               ::= { pppLqrEntry 3 }

          pppLqrRemotePeriod   OBJECT-TYPE
               SYNTAX    INTEGER(1..2147483648)
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The LQR reporting period, in hundredths of a
                         second, that is in effect for the remote PPP
                         entity."
               REFERENCE
                         "Section 2.5, Configuration Option Format, of
                         RFC1333."
               ::= { pppLqrEntry 4 }

          pppLqrOutLQRs   OBJECT-TYPE
               SYNTAX    Counter
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The value of the OutLQRs counter on the local
                         node for the link identified by ifIndex."
               REFERENCE
                         "Section 2.2, Counters, of RFC1333."
               ::= { pppLqrEntry 5 }

          pppLqrInLQRs   OBJECT-TYPE
               SYNTAX    Counter
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "The value of the InLQRs counter on the local
                         node for the link identified by ifIndex."
               REFERENCE
                         "Section 2.2, Counters, of RFC1333."
               ::= { pppLqrEntry 6 }

          --
          -- The PPP LQR Configuration table.
          --

          pppLqrConfigTable   OBJECT-TYPE
               SYNTAX    SEQUENCE OF PppLqrConfigEntry
               ACCESS    not-accessible
               STATUS    mandatory
               DESCRIPTION
                         "Table containing the LQR Configuration
                         parameters for the local PPP entity."
               ::= { pppLqr 2 }

          pppLqrConfigEntry   OBJECT-TYPE
               SYNTAX    PppLqrConfigEntry
               ACCESS    not-accessible
               STATUS    mandatory
               DESCRIPTION
                         "LQR configuration information for a particular
                         PPP link."
               INDEX     { ifIndex }
               ::= { pppLqrConfigTable 1 }

          PppLqrConfigEntry ::= SEQUENCE {
               pppLqrConfigPeriod
                    INTEGER,
               pppLqrConfigStatus
                    INTEGER
          }

          pppLqrConfigPeriod   OBJECT-TYPE
               SYNTAX    INTEGER(0..2147483647)
               ACCESS    read-write
               STATUS    mandatory
               DESCRIPTION
                         "The LQR Reporting Period that the local PPP
                         entity will attempt to negotiate with the
                         remote entity, in units of hundredths of a
                         second. Changing this object will have effect
                         when the link is next restarted."
               REFERENCE
                         "Section 2.5, Configuration Option Format, of
                         RFC1333."
               DEFVAL    { 0 }
               ::= { pppLqrConfigEntry 1 }

          pppLqrConfigStatus   OBJECT-TYPE
               SYNTAX    INTEGER {disabled (1), enabled (2)}
               ACCESS    read-write
               STATUS    mandatory
               DESCRIPTION
                         "If enabled(2) then the local node will attempt
                         to perform LQR negotiation with the remote
                         node. If disabled(1) then this negotiation is
                         not performed. In any event, the local node
                         will comply with any magic number negotiations
                         attempted by the remote node, per the PPP
                         specification. Changing this object will have
                         effect when the link is next restarted.
                         Setting this object to the value disabled(1)
                         has the effect of invalidating the
                         corresponding entry in the pppLqrConfigTable
                         object. It is an implementation-specific matter
                         as to whether the agent removes an invalidated
                         entry from the table. Accordingly, management
                         stations must be prepared to receive tabular
                         information from agents that corresponds to
                         entries not currently in use."
               REFERENCE
                         "Section 7.6, Magic Number, of RFC1331."

               DEFVAL    { enabled }
               ::= { pppLqrConfigEntry 2 }

          -- 4.3.  PPP LQR Extensions Group

          --
          -- The PPP LQR Extensions Group.
          -- Implementation of this group is optional.
          --
          -- The intent of this group is to allow external
          -- implementation of the policy mechanisms that
          -- are used to declare a link to be "bad" or not.
          --
          -- It is not practical to examine the MIB objects
          -- which are used to generate LQR packets since
          -- LQR policies tend to require synchronization of
          -- the values of all data used to determine Link
          -- Quality; i.e. the values of the relevant counters
          -- must all be taken at the same instant in time.
          --

          pppLqrExtnsTable   OBJECT-TYPE
               SYNTAX    SEQUENCE OF PppLqrExtnsEntry
               ACCESS    not-accessible
               STATUS    mandatory
               DESCRIPTION
                         "Table containing additional LQR information
                         for the local PPP entity."
               ::= { pppLqr 3 }

          pppLqrExtnsEntry   OBJECT-TYPE
               SYNTAX    PppLqrExtnsEntry
               ACCESS    not-accessible
               STATUS    mandatory
               DESCRIPTION
                         "Extended LQR information for a particular PPP
                         link. Assuming that this group has been
                         implemented, a PPP link will have an entry in
                         this table if and only if LQR Quality
                         Monitoring has been successfully negotiated for
                         said link."
               INDEX     { ifIndex }
               ::= { pppLqrExtnsTable 1 }

          PppLqrExtnsEntry ::= SEQUENCE {

               pppLqrExtnsLastReceivedLqrPacket
                    OCTET STRING(SIZE(68))
          }

          pppLqrExtnsLastReceivedLqrPacket   OBJECT-TYPE
               SYNTAX    OCTET STRING(SIZE(68))
               ACCESS    read-only
               STATUS    mandatory
               DESCRIPTION
                         "This object contains the most recently
                         received LQR packet.  The format of the packet
                         is as described in the LQM Protocol
                         specificiation. All fields of the packet,
                         including the `save' fields, are stored in this
                         object.

                         The LQR packet is stored in network byte order.
                         The LAP-B and PPP headers are not stored in
                         this object; the first four octets of this
                         variable contain the Magic-Number field, the
                         second four octets contain the LastOutLQRs
                         field and so on. The last four octets of this
                         object contain the SaveInOctets field of the
                         LQR packet."
               REFERENCE
                         "Section 2.6, Packet Format, of RFC1333"
               ::= { pppLqrExtnsEntry 1 }

          -- 4.4.  PPP Tests

          -- The extensions to the interface table in RFC1229 define a
          -- table through which the network manager can instruct the
          -- managed object to perform various tests of the interface. This
          -- is the ifExtnsTestTable.

          -- The PPP MIB defines two such tests.

          -- 4.4.1.  PPP Echo Test

          -- The PPP Echo Test is defined as

               pppEchoTest    OBJECT IDENTIFIER ::= { pppTests 1 }

          -- Invoking this test causes a PPP Echo Packet to be sent on the
          -- line. ifExtnsTestResult returns success(2) if the echo
          -- response came back properly. It returns failed(7) if the
          -- response did not properly return. The definition of "proper"

          -- in this context is left to the discretion of the implementor.

          -- 4.4.2.  PPP Discard Test

          -- The PPP Discard Test is defined as

               pppDiscardTest OBJECT IDENTIFIER ::= { pppTests 2 }

          -- Invoking this test causes a PPP Discard Packet to be sent on
          -- the line. ifExtnsTestResult returns success(2) if the discard
          -- packet was successfully transmitted and failed(7) if an error
          -- was detected on transmission. The definition of "transmission
          -- error" in this context is left to the discretion of the
          -- implementor.

          END

5.  Acknowledgements

   This document was produced by the PPP working group.  In addition to
   the working group, the author wishes to thank the following
   individuals for their comments and contributions:

          Bill Simpson -- Daydreamer
          Glenn McGregor -- Merit
          Jesse Walker -- DEC
          Chris Gunner -- DEC

6.  Security Considerations

   The PPP MIB affords the network operator the ability to configure and
   control the PPP links of a particular system.  This represents a
   security risk.

   These risks are addressed in the following manners:

      (1)  All variables which represent a significant security risk
           are placed in separate, optional, MIB Groups. As the MIB
           Group is the quantum of implementation within a MIB, the
           implementor of the MIB may elect not to implement these
           groups.

      (2)  The implementor may choose to implement the variables
           which present a security risk so that they may not be
           written, i.e., the variables are READ-ONLY. This method
           still presents a security risk, and is not recommended,
           in that the variables, specifically the PPP
           Authentication Protocols' variables, may be easily read.

      (3)  Using SNMPv2, the operator can place the variables into
           MIB views which are protected in that the parties which
           have access to those MIB views use authentication and
           privacy protocols, or the operator may elect to make
           these views not accessible to any party.  In order to
           facilitate this placement, all security-related variables
           are placed in separate MIB Tables. This eases the
           identification of the necessary MIB View Subtree.

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, Editors, "Management Information Base
       for Network Management of TCP/IP-based internets", STD 17, RFC
       1213, Performance Systems International, March 1991.

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

   [4]  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.

   [5] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
       STD 16, RFC 1212, Performance Systems International, Hughes LAN
       Systems, March 1991.

   [6] Rose, M., Editor, "A Convention for Defining Traps for use with
       the SNMP", RFC 1215, Performance Systems International, March
       1991.

   [7] McCloghrie, K., "Extensions to the Generic-Interface MIB", RFC
       1229, Hughes LAN Systems, Inc., May 1991.

   [8] Simpson, W., "The Point-to-Point Protocol for the Transmission of
       Multi-protocol Datagrams over Point-to-Point Links, RFC 1331,
       Daydreamer, May 1992.

   [9] McGregor, G., "The PPP Internet Protocol Control Protocol", RFC
       1332, Merit, May 1992.

  [10] Baker, F., "Point-to-Point Protocol Extensions for Bridging", RFC
       1220, ACC, April 1991.

  [11] Lloyd, B., and W. Simpson, "PPP Authentication Protocols", RFC
       1334, L&A, Daydreamer, October 1992.

  [12] Simpson, W., "PPP Link Quality Monitoring", RFC 1333, Daydreamer,
       May 1992.

  [13] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
       Network Management Protocol", STD 15, RFC 1157, SNMP Research,
       Performance Systems International, Performance Systems
       International, MIT Laboratory for Computer Science, May 1990.

8.  Author's Address

   Frank Kastenholz
   FTP Software, Inc.
   2 High Street
   North Andover, Mass 01845 USA

   Phone: (508) 685-4000
   EMail: kasten@ftp.com

 

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