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RFC 2115

Management Information Base for Frame Relay DTEs Using SMIv2

Pages: 32
Draft Standard
Obsoletes:  1315

Top   ToC   RFC2115 - Page 1
Network Working Group                                       C. Brown
Request for Comments: 2115                      Cadia Networks, Inc.
Obsoletes: 1315                                             F. Baker
Category: Standards Track                              Cisco Systems
                                                      September 1997



            Management Information Base for Frame Relay DTEs
                              Using SMIv2

1.  Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.


2.  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 Frame Relay interfaces
   on DTEs.

Table of Contents

   1 Status of this Memo ...................................    1
   2 Abstract ..............................................    1
   3 The SNMPv2 Network Management Framework ...............    2
   4 Overview ..............................................    2
   4.1 Frame Relay Operational Model .......................    2
   4.2 Textual Conventions .................................    6
   4.3 Structure of MIB ....................................    6
   5 Changes from RFC 1315 .................................    6
   6 Definitions ...........................................    8
   6.1 Data Link Connection Management Interface ...........    9
   6.2 Circuit Table .......................................   14
   6.3 Error Table .........................................   22
   6.4 Trap Management .....................................   25
   7 Security Issues .......................................   30
   8 Acknowledgments .......................................   30
   9 Authors' Addresses ....................................   31
   10 References ...........................................   31
Top   ToC   RFC2115 - Page 2
3.  The SNMPv2 Network Management Framework

   The major components of the SNMPv2 Network Management framework are
   described in the documents listed below.

   o    RFC 1902 [1] defines the Structure of Management
        Information (SMI), the mechanisms used for describing and
        naming objects for the purpose of management.

   o    STD 17, RFC 1213 [2] defines MIB-II, the core set of
        managed objects (MO) for the Internet suite of protocols.

   o    RFC 1905 [3] defines the protocol used for network access
        to managed objects.

   The framework is adaptable/extensible by defining new MIBs to suit
   the requirements of specific applications/protocols/situations.

   Managed objects are accessed via a virtual information store, the
   MIB.  Objects in the MIB are defined using the subset of Abstract
   Syntax Notation One (ASN.1) defined in the SMI. In particular, each
   object type is named by an OBJECT IDENTIFIER, which is 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, often a textual string, termed
   the descriptor, is used to refer to the object type.

4.  Overview

4.1.  Frame Relay Operational Model

   For the purposes of understanding this document, Frame Relay is
   viewed as a multi-access media, not as a group of point- to-point
   connections. This model proposes that Frame Relay is a single
   interface to the network (physical connection) with many destinations
   or neighbors (virtual connections). This view enables a network
   manager the ability to group all virtual connections with their
   corresponding physical connection thereby allowing simpler
   diagnostics and trouble shooting.

   With the extension of the interfaces MIB, it is possible to configure
   frame relay DLCs as individual interfaces and create ifTable entries
   for each. This is not recommended and is not directly supported by
   this MIB. Additionally, in the presence of demand circuits creation
   of individual ifEntries for each is not possible.
Top   ToC   RFC2115 - Page 3
   Should the user wish to group DLCs together to associate them with a
   higher layer, or to associate a DLC with an unnumbered point-to-point
   service, the frame relay DTE MIB provides an entry in the
   frCircuitEntry record. For example, suppose one were to configure a
   company proprietary protocol to run above several of the frame relay
   VCs. The basic layering would look something like the following:

      IP (ipaddrEntry 1 )  IP (ipaddrEntry 2)  IP (ipaddrEntry 3)
         |                    |                     |
         |                    |                     |
         |                    |              proprietary protocol
         |                    |              layer   (ifIndex 3)
         |                    |                     |
         |                    |                     |
      DLCI 20            DLCI 30            DLCI 40/41/42
      (ifIndex 2)        (ifIndex 2)         (ifIndex 2,
                                              logical ifIndex 3)
         |                    |                     |
         |                    |                     |
         |____________________|_____________________|
                              |
                              |
                      FR  DLMCI (ifIndex.2)
                              |
                              |
                   Physical Interface (ifIndex.1)



A configuration which specified that DLCI 40, 41,and 42 were associated
with a proprietary protocol layer, while DLCI 20 and 30 were to run IP
directly can now be expressed using a combination of frCircuitIfIndex
and frCircuitLogicalIfIndex.  In this particular case DLCIs 40, 41 and
42 would use frCircuitIfIndex equal to the frame relay interface level
(2) while their frCircuitLogicalIfIndex would indicate the proprietary
protocol (3). DLCIs 20 and 30 would have both instances set to the frame
relay interface (2).

      Object           Meaning for Frame Relay Interface
      ______           _____________________________________

      ifDescr          As per DESCRIPTION in RFC 1573.
      ifType           The value allocated for Frame Relay
                       Interfaces - frameRelay (32).

      ifMtu            Set to maximum frame size in octets for
                       this frame relay interface.
Top   ToC   RFC2115 - Page 4
      ifSpeed          The access rate for the frame relay
                       interface.  This could be different from
                       the speed of the underlying physical
                       interface, e.g. in a fractional T1 case
                       the access rate could be 384 kbits/s (the
                       value reported in this object) whereas the
                       speed of the underlying interface would be
                       1.544 Mbits/s (the value reported in the
                       instance of ifSpeed for the ifEntry with
                       type ds1).

      ifPhysAddress    The primary address for this interface
                       assigned by the Frame Relay interface
                       provider.  An octet string of zero length
                       if no address is used for this interface.

      ifAdminStatus    As per DESCRIPTION in RFC 1573.

      ifOperStatus     As per DESCRIPTION in RFC 1573.

      ifLastChange     As per DESCRIPTION in RFC 1573.

      ifInOctets       The number of received octets.  This
                       includes not only the information field
                       (user data) but also the frame relay header
                       and CRC.

      ifInUcastPkts    The number of frames received on non-
                       multicast DLCIs

      ifInDiscards     The number of frames that were successfully
                       received but were discarded because of
                       format errors or because the VC was not
                       known.  Format errors, in this case, are
                       any errors which would prevent the system
                       from recognizing the DLCI and placing the
                       error in the frCircuitDiscard category.

      ifInErrors       The number of received frames that are
                       discarded, because of an error.
                       Possible errors can be the following: the
                       frame relay frames were too long or were
                       too short, the frames had an invalid or
                       unrecognized DLCI values, or incorrect
                       header values.
Top   ToC   RFC2115 - Page 5
      ifInUnknownProtos  Number of unknown or unsupported
                       upper layer protocol frames received
                       and discarded.

      ifOutOctets      The number of received octets.  This
                       includes not only the information field
                       (user data) but also the frame relay header
                       and CRC.

      ifOutUcastpkts   The number of frames sent.

      ifOutDiscards    The number of frames discarded in the
                       transmit direction.

      ifOutErrors      The number of frames discarded in the
                       egress direction, because of errors.

      ifName           As per DESCRIPTION in RFC 1573.

      ifInMulticastPkts   The number of unerrored frames received
                          on a multicast DLCI.

      ifInBroadcastPkts   Always zero (0) as there are no broadcast
                          frames.

      ifOutMulticastPkts  The number of frames transmitted over a
                          multicast DLCI.

      ifOutBroadcastPkts  Always zero (0) as there are no broadcast
                          frames.

      ifHCInOctets     Only required when ifSpeed >= 155 Mbits/s.
     See
                       details for ifInOctets.

      ifHCOutOctets    Only required when ifSpeed >= 155 Mbits/s.
     See
                       details for ifInOctets.

      ifLinkUpDownTrapEnble  As per DESCRIPTION in RFC 1573.

      ifHighSpeed      The access rate of the frame relay interface
                       measured in Mbits/s.  If the access rate is
                       less than 1 Mbits/s, this object returns 0.

      ifPromiscuousMode   Set to false(2).

      ifConnectorPresent  Set to false(2).
Top   ToC   RFC2115 - Page 6
4.2.  Textual Conventions

   One new data type is introduced as a textual convention in this MIB
   document.  This textual convention enhances the readability of the
   specification and can ease comparison with other specifications if
   appropriate.  It should be noted that the introduction of this
   textual conventions has no effect on either the syntax nor the
   semantics of any managed objects.  The use of this 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 this textual conventions which is
   adopted merely for the convenience of readers and writers in pursuit
   of the elusive goal of clear, concise, and unambiguous MIB documents.

   The new data type is DLCI.  DLCI refers to the range 0..DLCINumber,
   and is used to refer to the valid Data Link Connection Indices.
   DLCINumber is, by definition, the largest possible DLCI value
   possible under the configured Q.922 Address Format.

4.3.  Structure of MIB

   The MIB is composed of three groups, one defining the Data Link
   Connection Management Interface (DLCMI), one describing the Circuits,
   and a third describing errors.

   During normal operation, Frame Relay virtual circuits will be added,
   deleted and change availability. The occurrence of such changes is of
   interest to the network manager and therefore, one trap is defined,
   intended to be corollary to the SNMP "Link Up" and "Link Down" traps.

5.  Changes from RFC 1315

   Below are listed the changes from the previously published version
   this document, which was RFC 1315:

   o    The MIB module was converted from SMIv1 to SMIv2 format.
        Note: due to this, the table indices have access of
        "read-only" instead of "not-accessible", which is the
        typical value for index objects in SMIv2.

   o    The module name was changed from RFC1315-MIB to FRAME-
        RELAY-DTE-MIB.

   o    The textual convention "Index" was dropped from the MIB
        module and "InterfaceIndex" from the interfaces MIB
        module, IF-MIB, was used in its place.
Top   ToC   RFC2115 - Page 7
   o    Objects frDlcmiStatus and frDlcmiRowStatus were added to
        table frDlcmiTable.

   o    Added values "itut933A(5)" (from CCITT Q933 Annex A) and
        "ansiT1617D1994(6)" (from ANSI T1.617a-1994 Annex D) to
        the enumerations for object frDlcmiState.

   o    The labels for the enumerated values for object
        frDlcmiAddressLen were renamed to remove their hyphens as
        required by SMIv2.

   o    Added clarification that the "management virtual circuit"
        (i.e. DLCI 0) is a member of the circuit table.

   o    Added the following objects to table frCircuitTable:
        frCircuitMulticast, frCircuitType, frCircuitDiscards,
        frCircuitReceivedDEs, frCircuitSentDEs,
        frCircuitLogicalIfIndex, and  frCircuitRowStatus.

   o    The definition of object frCircuitReceivedOctets was
        clarified as to which octets were counted.

   o    Added the objects frErrFaults and frErrFaultTime to table
        frErrTable.

   o    Added clarification to the values of object frErrType.

   o    Added size on definition of object frErrData and
        clarified what data to capture.

   o    Changed identififier for OID value { frameDelayDTE 4 }
        from frame-relay-globals to frameRelayTrapControl.

   o    Added object frTrapMaxRate.


   o    Created object groups frPortGroup, frCircuitGroup,
        frTrapGroup, frErrGroup, frPortGroup0, frCircuitGroup0,
        frTrapGroup0, and frErrGroup0.

   o    Created notification group frNotificationGroup.

   o    Created module compliances frCompliance and
        frCompliance0.

   o    Added ranges to objects frCircuitCommittedBurst,
        frCircuitExcessBurst, and frCircuitThroughput.
Top   ToC   RFC2115 - Page 8
6.  Definitions

     FRAME-RELAY-DTE-MIB DEFINITIONS ::= BEGIN

     IMPORTS
                 MODULE-IDENTITY, OBJECT-TYPE, Counter32,
                 Integer32, NOTIFICATION-TYPE            FROM SNMPv2-SMI
                 TEXTUAL-CONVENTION, RowStatus, TimeStamp FROM SNMPv2-TC
                 MODULE-COMPLIANCE, OBJECT-GROUP,
                 NOTIFICATION-GROUP                     FROM SNMPv2-CONF
                 transmission                           FROM RFC1213-MIB
                 InterfaceIndex                           FROM IF-MIB;

     --  Frame Relay DTE MIB

     frameRelayDTE MODULE-IDENTITY
         LAST-UPDATED "9705010229Z" -- Thu May  1 02:29:46 PDT 1997
         ORGANIZATION "IETF IPLPDN Working Group"
         CONTACT-INFO
            "       Caralyn Brown
            Postal: Cadia Networks, Inc.
                    1 Corporate Drive
                    Andover, Massachusetts  01810
            Tel:    +1 508 689 2400 x133
            E-Mail: cbrown@cadia.com

                    Fred Baker
            Postal: Cisco Systems
                    519 Lado Drive
                    Santa Barbara, California 93111
            Tel:    +1 408 526 425
            E-Mail: fred@cisco.com"
         DESCRIPTION
            "The MIB module to describe the use of a Frame Relay
            interface by a DTE."
         REVISION "9705010229Z" -- Thu May  1 02:29:46 PDT 1997
         DESCRIPTION
            "Converted from SMIv1 to SMIv2. (Thus, indices are
            read-only rather than being not-accessible.) Added
            objects and made clarifications based on implementation
            experience."

         REVISION "9204010000Z"
         DESCRIPTION
            "Published as RFC 1315, the initial version of this MIB
            module."
         ::= { transmission 32 }
Top   ToC   RFC2115 - Page 9
     --
     --      the range of a Data Link Connection Identifier
     --
     DLCI ::= TEXTUAL-CONVENTION
         STATUS      current
         DESCRIPTION
            "The range of DLCI values.  Note that this varies by
            interface configuration; normally, interfaces may use
            0..1023, but may be configured to use ranges as large
            as 0..2^23."
         SYNTAX      Integer32(0..8388607)



     --

     --  Data Link Connection Management Interface

     --      The variables that configure the DLC Management Interface.

     frDlcmiTable OBJECT-TYPE
         SYNTAX   SEQUENCE OF FrDlcmiEntry
         MAX-ACCESS   not-accessible
         STATUS   current
         DESCRIPTION
            "The Parameters for the Data Link Connection Management
            Interface for the frame relay service on this
            interface."
         REFERENCE
            "American National Standard T1.617-1991, Annex D"
         ::= { frameRelayDTE 1 }

     frDlcmiEntry OBJECT-TYPE
         SYNTAX   FrDlcmiEntry
         MAX-ACCESS   not-accessible
         STATUS   current
         DESCRIPTION
            "The Parameters for a particular Data Link Connection
            Management Interface."
         INDEX { frDlcmiIfIndex }
         ::= { frDlcmiTable 1 }
Top   ToC   RFC2115 - Page 10
     FrDlcmiEntry ::=
         SEQUENCE {
             frDlcmiIfIndex                  InterfaceIndex,
             frDlcmiState                    INTEGER,
             frDlcmiAddress                  INTEGER,
             frDlcmiAddressLen               INTEGER,
             frDlcmiPollingInterval          Integer32,
             frDlcmiFullEnquiryInterval      Integer32,
             frDlcmiErrorThreshold           Integer32,
             frDlcmiMonitoredEvents          Integer32,
             frDlcmiMaxSupportedVCs          DLCI,
             frDlcmiMulticast                INTEGER,
             frDlcmiStatus                   INTEGER,
             frDlcmiRowStatus                RowStatus
     }


     frDlcmiIfIndex OBJECT-TYPE

         SYNTAX   InterfaceIndex
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The ifIndex value of the corresponding ifEntry."
         ::= { frDlcmiEntry 1 }


     frDlcmiState OBJECT-TYPE
         SYNTAX INTEGER      {
             noLmiConfigured (1),
             lmiRev1         (2),
             ansiT1617D      (3),  -- ANSI T1.617 Annex D
             ansiT1617B      (4),  -- ANSI T1.617 Annex B
             itut933A        (5),  -- CCITT Q933 Annex A
             ansiT1617D1994  (6)   -- ANSI T1.617a-1994 Annex D
         }
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "This variable states which Data Link Connection
            Management scheme is active (and by implication, what
            DLCI it uses) on the Frame Relay interface."
         REFERENCE
            "American National Standard T1.617-1991, American
            National Standard T1.617a-1994, ITU-T Recommendation
            Q.933 (03/93)."

         ::= { frDlcmiEntry 2 }
Top   ToC   RFC2115 - Page 11
     frDlcmiAddress OBJECT-TYPE
         SYNTAX      INTEGER {
                     q921           (1),  -- 13 bit DLCI
                     q922March90    (2),  -- 11 bit DLCI
                     q922November90 (3),  -- 10 bit DLCI
                     q922           (4)   -- Final Standard
         }
         MAX-ACCESS  read-create
         STATUS  current
         DESCRIPTION
            "This variable states which address format is in use on
            the Frame Relay interface."
         ::= { frDlcmiEntry 3 }


     frDlcmiAddressLen OBJECT-TYPE
         SYNTAX  INTEGER     {
                 twoOctets (2),
                 threeOctets (3),
                 fourOctets (4)
         }
         MAX-ACCESS  read-create
         STATUS  current
         DESCRIPTION
            "This variable states the address length in octets.  In
            the case of Q922 format, the length indicates the
            entire length of the address including the control
            portion."
         ::= { frDlcmiEntry 4 }


     frDlcmiPollingInterval OBJECT-TYPE
         SYNTAX   Integer32 (5..30)
         UNITS    "seconds"
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "This is the number of seconds between successive
            status enquiry messages."
         REFERENCE
            "American National Standard T1.617-1991, Section D.7
            Timer T391."
         DEFVAL { 10 }
         ::= { frDlcmiEntry 5 }
Top   ToC   RFC2115 - Page 12
     frDlcmiFullEnquiryInterval OBJECT-TYPE
         SYNTAX   Integer32 (1..255)
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "Number of status enquiry intervals that pass before
            issuance of a full status enquiry message."
         REFERENCE
            "American National Standard T1.617-1991, Section D.7
            Counter N391."
         DEFVAL { 6 }
         ::= { frDlcmiEntry 6 }


     frDlcmiErrorThreshold OBJECT-TYPE
         SYNTAX   Integer32 (1..10)
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "This is the maximum number of unanswered Status
            Enquiries the equipment shall accept before declaring
            the interface down."
         REFERENCE
            "American National Standard T1.617-1991, Section D.5.1
            Counter N392."
         DEFVAL { 3 }
         ::= { frDlcmiEntry 7 }


     frDlcmiMonitoredEvents OBJECT-TYPE
         SYNTAX   Integer32 (1..10)
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "This is the number of status polling intervals over
            which the error threshold is counted.  For example, if
            within 'MonitoredEvents' number of events the station
            receives 'ErrorThreshold' number of errors, the
            interface is marked as down."
         REFERENCE
            "American National Standard T1.617-1991, Section D.5.2
            Counter N393."
         DEFVAL { 4 }
         ::= { frDlcmiEntry 8 }
Top   ToC   RFC2115 - Page 13
     frDlcmiMaxSupportedVCs OBJECT-TYPE
         SYNTAX   DLCI
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "The maximum number of Virtual Circuits allowed for
            this interface.  Usually dictated by the Frame Relay
            network.

            In response to a SET, if a value less than zero or
            higher than the agent's maximal capability is
            configured, the agent should respond badValue"
         ::= { frDlcmiEntry 9 }


     frDlcmiMulticast OBJECT-TYPE
         SYNTAX   INTEGER    {
                     nonBroadcast (1),
                     broadcast (2)
                     }
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "This indicates whether the Frame Relay interface is
            using a multicast service."
         ::= { frDlcmiEntry 10 }



     frDlcmiStatus OBJECT-TYPE
         SYNTAX   INTEGER    {
                     running      (1),    -- init complete, system running
                     fault        (2),    -- error threshold exceeded
                     initializing (3)     -- system start up
                     }
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "This indicates the status of the Frame Relay interface
            as determined by the performance of the dlcmi.  If no
            dlcmi is running, the Frame Relay interface will stay
            in the running state indefinitely."
         ::= { frDlcmiEntry 11 }
Top   ToC   RFC2115 - Page 14
     frDlcmiRowStatus OBJECT-TYPE
         SYNTAX   RowStatus
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "SNMP Version 2 Row Status Variable.  Writable objects
            in the table may be written in any RowStatus state."
         ::= { frDlcmiEntry 12 }


     --
     -- A Frame Relay service is a multiplexing service.  Data
     -- Link Connection Identifiers enumerate virtual circuits
     -- (permanent or dynamic) which are layered onto the underlying
     -- circuit, represented by ifEntry.  Therefore, each of the entries
     -- in the Standard MIB's Interface Table with an IfType of
     -- Frame Relay represents a Q.922 interface.  Zero or more
     -- virtual circuits are layered onto this interface and provide
     -- interconnection with various remote destinations.
     -- Each such virtual circuit is represented by an entry in the
     -- circuit table.  The management virtual circuit (i.e. DLCI 0)
     -- is a virtual circuit by this definition and will be represented
     -- with an entry in the circuit table.

     --   Circuit Table

     -- The table describing the use of the DLCIs attached to
     -- each Frame Relay Interface.

     frCircuitTable OBJECT-TYPE
         SYNTAX   SEQUENCE OF FrCircuitEntry
         MAX-ACCESS   not-accessible
         STATUS   current
         DESCRIPTION
            "A table containing information about specific Data
            Link Connections (DLC) or virtual circuits."
         ::= { frameRelayDTE 2 }
Top   ToC   RFC2115 - Page 15
     frCircuitEntry OBJECT-TYPE
         SYNTAX   FrCircuitEntry
         MAX-ACCESS   not-accessible
         STATUS   current
         DESCRIPTION
            "The information regarding a single Data Link
            Connection.  Discontinuities in the counters contained
            in this table are indicated by the value in
            frCircuitCreationTime."
         INDEX { frCircuitIfIndex, frCircuitDlci }
         ::= { frCircuitTable 1 }


     FrCircuitEntry ::=
         SEQUENCE {
             frCircuitIfIndex                InterfaceIndex,
             frCircuitDlci                   DLCI,
             frCircuitState                  INTEGER,
             frCircuitReceivedFECNs          Counter32,
             frCircuitReceivedBECNs          Counter32,
             frCircuitSentFrames             Counter32,
             frCircuitSentOctets             Counter32,
             frCircuitReceivedFrames         Counter32,
             frCircuitReceivedOctets         Counter32,
             frCircuitCreationTime           TimeStamp,
             frCircuitLastTimeChange         TimeStamp,
             frCircuitCommittedBurst         Integer32,
             frCircuitExcessBurst            Integer32,
             frCircuitThroughput             Integer32,
             frCircuitMulticast              INTEGER,
             frCircuitType                   INTEGER,
             frCircuitDiscards               Counter32,
             frCircuitReceivedDEs            Counter32,
             frCircuitSentDEs                Counter32,
             frCircuitLogicalIfIndex         InterfaceIndex,
             frCircuitRowStatus              RowStatus
     }


     frCircuitIfIndex OBJECT-TYPE
         SYNTAX   InterfaceIndex
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The ifIndex Value of the ifEntry this virtual circuit
            is layered onto."
         ::= { frCircuitEntry 1 }
Top   ToC   RFC2115 - Page 16
     frCircuitDlci OBJECT-TYPE
         SYNTAX   DLCI
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The Data Link Connection Identifier for this virtual
            circuit."
         REFERENCE
            "American National Standard T1.618-1991, Section 3.3.6"
         ::= { frCircuitEntry 2 }


     frCircuitState OBJECT-TYPE
         SYNTAX   INTEGER    {

                     invalid (1),
                     active (2),
                     inactive (3)
                  }
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "Indicates whether the particular virtual circuit is
            operational.  In the absence of a Data Link Connection
            Management Interface, virtual circuit entries (rows)
            may be created by setting virtual circuit state to
            'active', or deleted by changing Circuit state to
            'invalid'.

            Whether or not the row actually disappears is left to
            the implementation, so this object may actually read as
            'invalid' for some arbitrary length of time.  It is
            also legal to set the state of a virtual circuit to
            'inactive' to temporarily disable a given circuit.

            The use of 'invalid' is deprecated in this SNMP Version
            2 MIB, in favor of frCircuitRowStatus."
         DEFVAL { active }
         ::= { frCircuitEntry 3 }
Top   ToC   RFC2115 - Page 17
     frCircuitReceivedFECNs OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "Number of frames received from the network indicating
            forward congestion since the virtual circuit was
            created.  This occurs when the remote DTE sets the FECN
            flag, or when a switch in the network enqueues the
            frame to a trunk whose transmission queue is
            congested."
         REFERENCE
            "American National Standard T1.618-1991, Section 3.3.3"
         ::= { frCircuitEntry 4 }


     frCircuitReceivedBECNs OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only


         STATUS   current
         DESCRIPTION
            "Number of frames received from the network indicating
            backward congestion since the virtual circuit was
            created.  This occurs when the remote DTE sets the BECN
            flag, or when a switch in the network receives the
            frame from a trunk whose transmission queue is
            congested."
         REFERENCE
            "American National Standard T1.618-1991, Section 3.3.4"
         ::= { frCircuitEntry 5 }


     frCircuitSentFrames OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The number of frames sent from this virtual circuit
            since it was created."
         ::= { frCircuitEntry 6 }


     frCircuitSentOctets OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only
         STATUS   current
Top   ToC   RFC2115 - Page 18
         DESCRIPTION
            "The number of octets sent from this virtual circuit
            since it was created.  Octets counted are the full
            frame relay header and the payload, but do not include
            the flag characters or CRC."
         ::= { frCircuitEntry 7 }


     frCircuitReceivedFrames OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "Number of frames received over this virtual circuit
            since it was created."
         ::= { frCircuitEntry 8 }


     frCircuitReceivedOctets OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "Number of octets received over this virtual circuit
            since it was created.  Octets counted include the full
            frame relay header, but do not include the flag
            characters or the CRC."
         ::= { frCircuitEntry 9 }


     frCircuitCreationTime OBJECT-TYPE
         SYNTAX   TimeStamp
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The value of sysUpTime when the virtual circuit was
            created, whether by the Data Link Connection Management
            Interface or by a SetRequest."
         ::= { frCircuitEntry 10 }
Top   ToC   RFC2115 - Page 19
     frCircuitLastTimeChange OBJECT-TYPE
         SYNTAX   TimeStamp
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The value of sysUpTime when last there was a change in
            the virtual circuit state"
         ::= { frCircuitEntry 11 }


     frCircuitCommittedBurst OBJECT-TYPE
         SYNTAX   Integer32(0..2147483647)
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "This variable indicates the maximum amount of data, in
            bits, that the network agrees to transfer under normal
            conditions, during the measurement interval."
         REFERENCE
            "American National Standard T1.617-1991, Section
            6.5.19"
         DEFVAL   { 0 }  -- the default indicates no commitment
         ::= { frCircuitEntry 12 }


     frCircuitExcessBurst OBJECT-TYPE
         SYNTAX   Integer32(0..2147483647)
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "This variable indicates the maximum amount of
            uncommitted data bits that the network will attempt to
            deliver over the measurement interval.

            By default, if not configured when creating the entry,
            the Excess Information Burst Size is set to the value
            of ifSpeed."
         REFERENCE
            "American National Standard T1.617-1991, Section
            6.5.19"
         ::= { frCircuitEntry 13 }


     frCircuitThroughput OBJECT-TYPE
         SYNTAX   Integer32(0..2147483647)
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
Top   ToC   RFC2115 - Page 20
            "Throughput is the average number of 'Frame Relay
            Information Field' bits transferred per second across a
            user network interface in one direction, measured over
            the measurement interval.

            If the configured committed burst rate and throughput
            are both non-zero, the measurement interval, T, is
                T=frCircuitCommittedBurst/frCircuitThroughput.

            If the configured committed burst rate and throughput
            are both zero, the measurement interval, T, is
                       T=frCircuitExcessBurst/ifSpeed."
         REFERENCE
            "American National Standard T1.617-1991, Section
            6.5.19"
         DEFVAL {0}  -- the default value of Throughput is
                     -- "no commitment".
         ::= { frCircuitEntry 14 }


     frCircuitMulticast OBJECT-TYPE
         SYNTAX   INTEGER    {
                     unicast   (1),
                     oneWay    (2),
                     twoWay    (3),
                     nWay      (4)
                     }
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "This indicates whether this VC is used as a unicast VC
            (i.e. not multicast) or the type of multicast service
            subscribed to"
         REFERENCE
            "Frame Relay PVC Multicast Service and Protocol
            Description Implementation: FRF.7 Frame Relay Forum
            Technical Committe October 21, 1994"
              DEFVAL {unicast}
                          -- the default value of frCircuitMulticast is
                          -- "unicast" (not a multicast VC).
              ::= { frCircuitEntry 15 }


     frCircuitType OBJECT-TYPE
         SYNTAX   INTEGER    {
                     static  (1),
                     dynamic (2)
                  }
Top   ToC   RFC2115 - Page 21
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "Indication of whether the VC was manually created
            (static), or dynamically created (dynamic) via the data
            link control management interface."
         ::= { frCircuitEntry 16 }


     frCircuitDiscards OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The number of inbound frames dropped because of format
            errors, or because the VC is inactive."
         ::= { frCircuitEntry 17 }


     frCircuitReceivedDEs OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "Number of frames received from the network indicating
            that they were eligible for discard since the virtual
            circuit was created.  This occurs when the remote DTE
            sets the DE flag, or when in remote DTE's switch
            detects that the frame was received as Excess Burst
            data."
         REFERENCE
            "American National Standard T1.618-1991, Section 3.3.4"
         ::= { frCircuitEntry 18 }


     frCircuitSentDEs OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "Number of frames sent to the network indicating that
            they were eligible for discard since the virtual
            circuit was created.   This occurs when the local DTE
            sets the DE flag, indicating that during Network
            congestion situations those frames should be discarded
            in preference of other frames sent without the DE bit
            set."
         REFERENCE
Top   ToC   RFC2115 - Page 22
            "American National  Standard  T1.618-1991, Section
            3.3.4"
        ::= { frCircuitEntry 19 }

     frCircuitLogicalIfIndex OBJECT-TYPE
         SYNTAX  InterfaceIndex
         MAX-ACCESS read-create
         STATUS  current
         DESCRIPTION
            "Normally the same value as frDlcmiIfIndex, but
            different when an implementation associates a virtual
            ifEntry with a DLC or set of DLCs in order to associate
            higher layer objects such as the ipAddrEntry with a
            subset of the virtual circuits on a Frame Relay
            interface. The type of such ifEntries is defined by the
            higher layer object; for example, if PPP/Frame Relay is
            implemented, the ifType of this ifEntry would be PPP.
            If it is not so defined, as would be the case with an
            ipAddrEntry, it should be of type Other."
        ::= { frCircuitEntry 20 }

     frCircuitRowStatus OBJECT-TYPE
         SYNTAX   RowStatus
         MAX-ACCESS   read-create
         STATUS   current
         DESCRIPTION
            "This object is used to create a new row or modify or
            destroy an existing row in the manner described in the
            definition of the RowStatus textual convention.
            Writable objects in the table may be written in any
            RowStatus state."
         ::= { frCircuitEntry 21 }


     --
     --  Error Table

     -- The table describing errors encountered on each Frame
     -- Relay Interface.

     frErrTable OBJECT-TYPE
         SYNTAX   SEQUENCE OF FrErrEntry
         MAX-ACCESS   not-accessible
         STATUS   current
         DESCRIPTION
            "A table containing information about Errors on the
            Frame Relay interface.  Discontinuities in the counters
            contained in this table are the same as apply to the
Top   ToC   RFC2115 - Page 23
            ifEntry associated with the Interface."
         ::= { frameRelayDTE 3 }

     frErrEntry OBJECT-TYPE
         SYNTAX   FrErrEntry
         MAX-ACCESS   not-accessible
         STATUS   current
         DESCRIPTION
            "The error information for a single frame relay
            interface."
         INDEX { frErrIfIndex }
         ::= { frErrTable 1 }


     FrErrEntry ::=
         SEQUENCE {
             frErrIfIndex            InterfaceIndex,
             frErrType               INTEGER,
             frErrData               OCTET STRING,
             frErrTime               TimeStamp,
             frErrFaults             Counter32,
             frErrFaultTime          TimeStamp
     }


     frErrIfIndex OBJECT-TYPE
         SYNTAX   InterfaceIndex
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The ifIndex Value of the corresponding ifEntry."
         ::= { frErrEntry 1 }


         frErrType OBJECT-TYPE
             SYNTAX   INTEGER    {
                         unknownError(1),
                         receiveShort(2),
                         receiveLong(3),
                         illegalAddress(4),
                         unknownAddress(5),
                         dlcmiProtoErr(6),
                         dlcmiUnknownIE(7),
                         dlcmiSequenceErr(8),
                         dlcmiUnknownRpt(9),
                         noErrorSinceReset(10)
                      }
Top   ToC   RFC2115 - Page 24
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
     "The type of error that was last seen  on  this interface:

     receiveShort: frame was not long enough to allow
             demultiplexing - the address field was incomplete,
             or for virtual circuits using Multiprotocol over
             Frame Relay, the protocol identifier was missing
             or incomplete.

     receiveLong: frame exceeded maximum length configured for this
                  interface.

     illegalAddress: address field did not match configured format.

     unknownAddress: frame received on a virtual circuit which was not
                     active or administratively disabled.

     dlcmiProtoErr: unspecified error occurred when attempting to
                    interpret link maintenance frame.

     dlcmiUnknownIE: link maintenance frame contained an Information
                     Element type which is not valid for the
                     configured link maintenance protocol.

     dlcmiSequenceErr: link maintenance frame contained a sequence
                       number other than the expected value.

     dlcmiUnknownRpt: link maintenance frame contained a Report Type
                      Information Element whose value was not valid
                      for the configured link maintenance protocol.

     noErrorSinceReset: no errors have been detected since the last
                        cold start or warm start."
         ::= { frErrEntry 2 }


     frErrData OBJECT-TYPE
         SYNTAX   OCTET STRING (SIZE(1..1600))
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "An octet string containing as much of the error packet
            as possible.  As a minimum, it must contain the Q.922
            Address or as much as was delivered.  It is desirable
            to include all header and demultiplexing information."
         ::= { frErrEntry 3 }
Top   ToC   RFC2115 - Page 25
     frErrTime OBJECT-TYPE
         SYNTAX   TimeStamp
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The value of sysUpTime at which the error was
            detected."
         ::= { frErrEntry 4 }


     frErrFaults OBJECT-TYPE
         SYNTAX   Counter32
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The number of times the interface has gone down since
            it was initialized."
         ::= { frErrEntry 5 }


     frErrFaultTime OBJECT-TYPE
         SYNTAX   TimeStamp
         MAX-ACCESS   read-only
         STATUS   current
         DESCRIPTION
            "The value of sysUpTime at the time when the interface
            was taken down due to excessive errors.  Excessive
            errors is defined as the time when a DLCMI exceeds the
            frDlcmiErrorThreshold number of errors within
            frDlcmiMonitoredEvents. See FrDlcmiEntry for further
            details."
         ::= { frErrEntry 6 }


     --

     -- Frame Relay Trap Control

     frameRelayTrapControl OBJECT IDENTIFIER ::= { frameRelayDTE 4 }

     -- the following highly unusual OID is as it is for compatibility
     -- with RFC 1315, the SNMP V1 predecessor of this document.
     frameRelayTraps OBJECT IDENTIFIER ::= { frameRelayDTE 0 }
Top   ToC   RFC2115 - Page 26
     frTrapState OBJECT-TYPE
         SYNTAX  INTEGER     { enabled(1), disabled(2) }
         MAX-ACCESS   read-write
         STATUS   current
         DESCRIPTION
            "This variable indicates whether the system produces
            the frDLCIStatusChange trap."
         DEFVAL { disabled }
         ::= { frameRelayTrapControl 1 }

     frTrapMaxRate OBJECT-TYPE
         SYNTAX  Integer32 (0..3600000)
         MAX-ACCESS   read-write
         STATUS   current
         DESCRIPTION
            "This variable indicates the number of milliseconds
            that must elapse between trap emissions.  If events
            occur more rapidly, the impementation may simply fail
            to trap, or may queue traps until an appropriate time."
         DEFVAL { 0 }        -- no minimum elapsed period is specified
         ::= { frameRelayTrapControl 2 }



     --  Data Link Connection Management Interface Related Traps

     frDLCIStatusChange NOTIFICATION-TYPE
         OBJECTS  { frCircuitState }
         STATUS      current


         DESCRIPTION
            "This trap indicates that the indicated Virtual Circuit
            has changed state.  It has either been created or
            invalidated, or has toggled between the active and
            inactive states.  If, however, the reason for the state
            change is due to the DLCMI going down, per-DLCI traps
            should not be generated."
     ::= { frameRelayTraps 1 }
     -- conformance information

     frConformance OBJECT IDENTIFIER ::= { frameRelayDTE 6 }

     frGroups      OBJECT IDENTIFIER ::= { frConformance 1 }
     frCompliances OBJECT IDENTIFIER ::= { frConformance 2 }

     -- compliance statements
Top   ToC   RFC2115 - Page 27
     frCompliance MODULE-COMPLIANCE
         STATUS  current
         DESCRIPTION
            "The compliance statement "
         MODULE  -- this module
         MANDATORY-GROUPS { frPortGroup, frCircuitGroup }

         GROUP       frErrGroup
         DESCRIPTION
            "This optional group is used for debugging Frame Relay
            Systems."

         GROUP       frTrapGroup
         DESCRIPTION
            "This optional group is used for the management of
            asynchronous notifications by Frame Relay Systems."

         GROUP       frNotificationGroup
         DESCRIPTION
            "This optional group defines the asynchronous
            notifications generated by Frame Relay Systems."

         OBJECT      frDlcmiRowStatus
         MIN-ACCESS  read-only
         DESCRIPTION
            "Row creation is not required for the frDlcmiTable."

         OBJECT      frCircuitRowStatus

         MIN-ACCESS  read-only
         DESCRIPTION
            "Row creation is not required for the frCircuitTable."

         ::= { frCompliances 1 }

     frCompliance0 MODULE-COMPLIANCE
         STATUS  current
         DESCRIPTION
            "The compliance statement for objects and the trap
            defined in RFC 1315."
         MODULE  -- this module
         MANDATORY-GROUPS { frPortGroup0, frCircuitGroup0 }

         GROUP       frErrGroup0
         DESCRIPTION
            "This optional group is used for debugging Frame Relay
            Systems."
Top   ToC   RFC2115 - Page 28
         GROUP       frTrapGroup0
         DESCRIPTION
            "This optional group is used for the management of
            asynchronous notifications by Frame Relay Systems."

         GROUP       frNotificationGroup
         DESCRIPTION
            "This optional group defines the asynchronous
            notifications generated by Frame Relay Systems."

         ::= { frCompliances 2 }

     -- units of conformance

     frPortGroup    OBJECT-GROUP
         OBJECTS {
                   frDlcmiIfIndex, frDlcmiState, frDlcmiAddress,
                   frDlcmiAddressLen, frDlcmiPollingInterval,
                   frDlcmiFullEnquiryInterval, frDlcmiErrorThreshold,
                   frDlcmiMonitoredEvents, frDlcmiMaxSupportedVCs,
                   frDlcmiMulticast, frDlcmiStatus, frDlcmiRowStatus
                }
         STATUS  current
         DESCRIPTION
            "The objects necessary to control the Link Management
            Interface for a Frame Relay Interface as well as
            maintain the error statistics on this interface."
         ::= { frGroups 1 }

     frCircuitGroup    OBJECT-GROUP
         OBJECTS {
                   frCircuitIfIndex, frCircuitDlci, frCircuitState,
                   frCircuitReceivedFECNs, frCircuitReceivedBECNs,
                   frCircuitSentFrames, frCircuitSentOctets,
                   frCircuitReceivedFrames, frCircuitReceivedOctets,
                   frCircuitCreationTime, frCircuitLastTimeChange,
                   frCircuitCommittedBurst, frCircuitExcessBurst,
                   frCircuitThroughput, frCircuitMulticast,
                   frCircuitType, frCircuitDiscards,
                   frCircuitReceivedDEs, frCircuitSentDEs,
                   frCircuitLogicalIfIndex, frCircuitRowStatus
                 }
         STATUS  current
         DESCRIPTION
            "The objects necessary to control the Virtual Circuits
            layered onto a Frame Relay Interface."
         ::= { frGroups 2 }
Top   ToC   RFC2115 - Page 29
     frTrapGroup    OBJECT-GROUP
         OBJECTS { frTrapState, frTrapMaxRate }
         STATUS  current
         DESCRIPTION
            "The objects necessary to control a Frame Relay
            Interface's notification messages."
         ::= { frGroups 3 }

     frErrGroup    OBJECT-GROUP
         OBJECTS {
                   frErrIfIndex, frErrType, frErrData, frErrTime,
                   frErrFaults, frErrFaultTime
                }
         STATUS  current
         DESCRIPTION
            "Objects designed to assist in debugging Frame Relay
            Interfaces."
         ::= { frGroups 4 }

     frNotificationGroup NOTIFICATION-GROUP
         NOTIFICATIONS { frDLCIStatusChange }
         STATUS  current
         DESCRIPTION
            "Traps which may be used to enhance event driven
            management of the interface."
         ::= { frGroups 5 }

     frPortGroup0    OBJECT-GROUP
         OBJECTS {
                   frDlcmiIfIndex, frDlcmiState, frDlcmiAddress,
                   frDlcmiAddressLen, frDlcmiPollingInterval,
                   frDlcmiFullEnquiryInterval, frDlcmiErrorThreshold,
                   frDlcmiMonitoredEvents, frDlcmiMaxSupportedVCs,
                   frDlcmiMulticast
                }
         STATUS  current
         DESCRIPTION
            "The objects necessary to control the Link Management
            Interface for a Frame Relay Interface as well as
            maintain the error statistics on this interface from
            RFC 1315."
         ::= { frGroups 6 }

     frCircuitGroup0    OBJECT-GROUP
         OBJECTS {
                   frCircuitIfIndex, frCircuitDlci, frCircuitState,
                   frCircuitReceivedFECNs, frCircuitReceivedBECNs,
                   frCircuitSentFrames, frCircuitSentOctets,
Top   ToC   RFC2115 - Page 30
                   frCircuitReceivedFrames, frCircuitReceivedOctets,
                   frCircuitCreationTime, frCircuitLastTimeChange,
                   frCircuitCommittedBurst, frCircuitExcessBurst,
                   frCircuitThroughput
                 }
         STATUS  current
         DESCRIPTION
            "The objects necessary to control the Virtual Circuits
            layered onto a Frame Relay Interface from RFC 1315."
         ::= { frGroups 7 }

     frErrGroup0    OBJECT-GROUP
         OBJECTS {
                   frErrIfIndex, frErrType, frErrData, frErrTime
                }
         STATUS  current
         DESCRIPTION
            "Objects designed to assist in debugging Frame Relay
            Interfaces from RFC 1315."
         ::= { frGroups 8 }


     frTrapGroup0    OBJECT-GROUP
         OBJECTS { frTrapState }
         STATUS  current
         DESCRIPTION
            "The objects necessary to control a Frame Relay
            Interface's notification messages from RFC 1315."
         ::= { frGroups 9 }

     END


7.  Security Issues

   Security issues for this MIB are entirely covered by the SNMP
   Security Architecture, and have not been expanded within the contents
   of this MIB.

8.  Acknowledgments

   This document was originally produced by the IP Over Large Public
   Data Networks (IPLPDN) Working Group, and has since been carried on
   in the PPP Working Group, sort of. Currently, the Ion Working Group
   is its host.

   Special thanks to James Watt of Newbridge Networks for his fine
   suggestions and pastable text.
Top   ToC   RFC2115 - Page 31
9.  Authors' Addresses

   Caralyn Brown
   Cadia Networks, Inc.
   1 Corporate Dirve
   Andover, Massachusetts  01810
   Telephone:  +1 508 689 2400 x133
   E-Mail: cbrown@cadia.com

   Fred Baker
   Cisco Systems
   519 Lado Drive
   Santa Barbara, California 93111
   Telephone  +1 408 526 4257
   E-Mail: fred@cisco.com

10.  References

   [1]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M.,
        and S. Waldbusser, "Structure of Management Information
        for Version 2 of the Simple Network Management Protocol
        (SNMPv2)", RFC 1902, January 1996.

   [2]  McCloghrie, K., and M. Rose, Editors, "Management
        Information Base for Network Management of TCP/IP-based
        internets: MIB-II", STD 17, RFC 1213, Hughes LAN Systems,
        Performance Systems International, March 1991.

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

   [4]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M.,
        and S. Waldbusser, "Protocol Operations for Version 2 of
        the Simple Network Management Protocol (SNMPv2)", RFC
        1905, January 1996.

   [5]  McCloghrie, K. and F. Kastenholz, "Evolution of the
        Interfaces Group of MIB-II", RFC 1573, Hughes LAN
        Systems, FTP Software, January 1994.

   [6]  T. Bradley, C. Brown, A. Malis, "Multiprotocol
        Interconnect over Frame Relay", RFC 1490, 07/26/1993.

   [7]  International Telegraph and Telephone Consultative
        Committee, "ISDN Data Link Layer Specification for Frame
        Mode Bearer Services", CCITT Recommendation Q.922, 19
Top   ToC   RFC2115 - Page 32
        April 1991.

   [8]  American National Standard For Telecommunications -
        Integrated Services Digital Network - Frame Relay Bearer
        Service - Architectural Framework and Service
        Description, ANSI T1.606-1991, 18 June 1991.

   [9]  American National Standard For Telecommunications -
        Integrated Services Digital Network - Digital Subscriber
        Signalling System No. 1 - Signaling Specification for
        Frame Relay Bearer Service, ANSI T1.617-1991, 18 June
        1991.

   [10] American National Standard For Telecommunications -
        Integrated Services Digital Network - Core Aspects of
        Frame Protocol for Use with Frame Relay Bearer Service,
        ANSI T1.618-1991, 18 June 1991.