Network Working Group                                           F. Baker
Request for Comments: 1232        Advanced Computer Communications, Inc.
                                                                 C. Kolb
                                 Performance Systems International, Inc.
                                                                 Editors
                                                                May 1991


                     Definitions of Managed Objects
                       for the DS1 Interface Type

Status of this Memo

   This memo defines objects for managing DS1 Interface objects for use
   with the SNMP protocol.  This memo is a product of the Transmission
   MIB Working Group of the Internet Engineering Task Force (IETF).
   This RFC specifies an IAB standards track protocol for the Internet
   community, and requests discussion and suggestions for improvements.
   Please refer to the current edition of the "IAB Official Protocol
   Standards" for the standardization state and status of this protocol.
   Distribution of this memo is unlimited.

Table of Contents

   1. Abstract ..............................................    1
   2. The Network Management Framework.......................    2
   3. Objects ...............................................    2
   3.1 Format of Definitions ...............................     3
   4. Overview ..............................................    3
   4.1 Binding between Interfaces and CSUs .................     3
   4.2 Objectives of this MIB Module .......................     4
   4.3 DS1 Terminology .....................................     4
   5. Definitions ...........................................    6
   5.1 The DS1 Configuration Group .........................     6
   5.2 The DS1 Interval Group ..............................    13
   5.3 The DS1 Current Group ...............................    16
   5.4 The DS1 Total Group .................................    19
   5.5 The DS1 Fractional Group ............................    22
   6. Acknowledgements ......................................   25
   7. References ............................................   26
   8. Security Considerations................................   27
   9. Authors' Addresses.....................................   28

1.  Abstract

   This memo defines an experimental portion of the Management
   Information Base (MIB) for use with network management protocols in
   TCP/IP-based internets.  In particular, this memo defines MIB objects



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   for representing DS1 physical interfaces.  Implementors should
   consult in addition to this memo the companion document that
   describes that DS3 managed objects.

2.  The Network Management Framework

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

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

      RFC 1156 which defines MIB-I, the core set of managed objects for
      the Internet suite of protocols.  RFC 1213, defines MIB-II, an
      evolution of MIB-I based on implementation experience and new
      operational requirements.

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

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

3.  Objects

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the subset of Abstract Syntax Notation One (ASN.1) [7]
   defined in the SMI.  In particular, each object has a name, a syntax,
   and an encoding.  The name is an object identifier, an
   administratively assigned name, which specifies an object type.  The
   object type together with an object instance serves to uniquely
   identify a specific instantiation of the object.  For human
   convenience, we often use a textual string, termed the OBJECT
   DESCRIPTOR, to also refer to the object type.

   The syntax of an object type defines the abstract data structure
   corresponding to that object type.  The ASN.1 language is used for
   this purpose.  However, the SMI [3] purposely restricts the ASN.1
   constructs which may be used.  These restrictions are explicitly made
   for simplicity.

   The encoding of an object type is simply how that object type is
   represented using the object type's syntax.  Implicitly tied to the
   notion of an object type's syntax and encoding is how the object type
   is represented when being transmitted on the network.



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   The SMI specifies the use of the basic encoding rules of ASN.1 [8],
   subject to the additional requirements imposed by the SNMP.

3.1.  Format of Definitions

   Section 5 contains 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 [13].

4.  Overview

   These objects are used when the particular media being used to
   realize an interface is a DS1 physical interface.  At present, this
   applies to these values of the ifType variable in the Internet-
   standard MIB:

               ds1 (18)
               e1  (19)

   The definitions contained herein are based on the AT&T T-1
   specifications and Extended Superframe (ESF) format [9, 10], the
   latter of which conforms to proposed ANSI specifications [14, 15].
   The various T1 and E1 line disciplines are similar enough that
   separate MIBs are unwarranted, although there are some differences.
   For example, Loss of Frame is defined more rigorously in the ESF
   specification than in the D4 specification, but it is defined in
   both.

4.1.  Binding between Interfaces and CSUs

   It should be noted that it is possible to multiplex multiple bit
   streams onto a single DS1 physical interface (CSU), realizing
   multiple interfaces from the perspective of the Internet-standard
   MIB.  It is also possible to concatenate physical interfaces to
   provide a single logical interface.  As such, it is important to be
   able to distinguish between the indices used to identify the CSUs
   attached to a node and the indices used to identify an interface (in
   the MIB sense) attached to a node.

   Each agent which resides on a host which uses DS1 physical interfaces
   is required to assign a small, positive integer uniquely to each CSU.
   This is known as the "CSUIndex", and is used to distinguish between
   different CSUs attached to a node.  The CSUIndex is also used as the
   "key" when accessing tabular information about DS1 physical
   interfaces.

   The potentially many-to-one binding between CSU indices and the



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   ifIndex value assigned to each MIB interface are defined in the
   ds1ConfigTable table defined in the next section.

4.2.  Objectives of this MIB Module

   There are numerous things that could be included in a MIB for DS1
   Interfaces: the management of multiplexors, CSUs, DSUs, and the like.
   The intent of this document is to facilitate the common management of
   CSUs, both in-chassis and external via proxy.  As such, a design
   decision was made up front to very closely align the MIB with the set
   of objects that can generally be read from CSUs that are currently
   deployed, which is to say ESF CSUs conforming to AT&T specifications.
   However, by simple generalization of these objects, the MIB is also
   made applicable to D4 and G.704 devices.

   To meet a requirement not easily satisfied in other places, there is
   one additional group present, the Fractional DS1 group.  This is
   intended to facilitate the use of fractional DS1 devices (i.e.,
   devices which utilize a subset of the 8 bit channels available in the
   frame) over the managed CSUs.

4.3.  DS1 Terminology

   The terminology used in this document to describe error conditions on
   a T1 or E1 circuit monitored by a CSU are from references [10], [11],
   [14], and [15].

          Out of Frame event
               An Out of Frame event is declared when the receiver
               detects two or more framing-bit errors within a 3
               millisecond period, or two or more errors out of five or
               less consecutive framing-bits.  At this time, the framer
               enters the Out of Frame State, and starts searching for a
               correct framing pattern.  The Out of Frame state ends
               when reframe occurs.

          Loss of Signal
               This event is declared upon observing 175 +/- 75
               contiguous pulse positions with no pulses of either
               positive or negative polarity (also called keep alive).

          Code Violation Error Event
               A Code Violation Error Event is the occurrence of a
               received Cyclic Redundancy Check code that is not
               identical to the corresponding locally-calculated code.

          Bipolar Violation
               A Bipolar Violation, for B8ZS-coded signals, is the



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               occurrence of a received bipolar violation that is not
               part of a zero-substitution code.  It also includes other
               error patterns such as: eight or more consecutive zeros
               and incorrect parity.

          Errored Seconds
               An Errored Second is a second with one or more Code
               Violation Error Events OR one or more Out of Frame
               events.  In D4 and G.704 section 2.1.3.2 (eg, G.704 which
               does not implement the CRC), the presence of Bipolar
               Violations also triggers an Errored Second.

          Severely Errored Seconds
               A Severely Errored Second is a second with 320 or more
               Code Violation Error Events OR one or more Out of Frame
               events.

          Severely Errored Framing Second
               An Severely Errored Framing Second is a second with one
               or more Out of Frame events.

          Unavailable Signal State
               This state is declared at the onset of 10 consecutive
               Severely Errored Seconds.  It is cleared at the onset of
               10 consecutive seconds with no Severely Errored Second.

          Unavailable Seconds
               Unavailable Seconds are calculated by counting the number
               of seconds that the CSU is in the Unavailable Signal
               State, including the initial 10 seconds to enter the
               state but not including the 10 seconds to exit the state.

               Note that any second that may be counted as an
               Unavailable Second may not be counted as an Errored
               Second, a Severely Errored Second.  Since the 10 Severely
               Errored Seconds that comprise the transition from the
               available to Unavailable Signal State may also be counted
               as Errored Seconds, and Severely Errored Seconds previous
               to entering the state, these three counters are adjusted
               so that any second counted during this transition is then
               subtracted.  The 10 seconds in the transition from
               unavailable to available may be counted as Errored
               Seconds.

               A special case exists when the 10 or more second period
               crosses the 900 second statistics window boundary, as the
               foregoing description implies that the Severely Errored
               Second and Unavailable Second counters must be adjusted



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               when the Unavailable Signal State is entered.  Clearly,
               successive GETs of the affected ds1IntervalSES and
               ds1IntervalUAS objects will return differing values if
               the first GET occurs during the first few seconds of the
               window.  This is viewed as an unavoidable side-effect of
               selecting the presently deployed AT&T objects as a basis
               for this memo.

          Yellow Alarm
               A Yellow Alarm is declared because of an incoming Yellow
               Signal from the far-end.  In effect, the circuit is
               declared to be a one way link.

          Red Alarm
               A Red Alarm is declared because of an incoming Loss of
               Signal, Loss of Framing, Alarm Indication Signal.  After
               a Red Alarm is declared, the device sends a Yellow Signal
               to the far-end.  The far-end, when receives the Yellow
               Signal, declares a Yellow Alarm.

          Circuit Identifier
               This is a character string specified by the circuit
               vendor, and is useful when communicating with the vendor
               during the troubleshooting process.

5.  Definitions


          RFC1232-MIB DEFINITIONS ::= BEGIN

          IMPORTS
                  experimental, Counter
                          FROM RFC1155-SMI
                  DisplayString
                          FROM RFC1158-MIB
                  OBJECT-TYPE
                          FROM RFC-1212;

          --  This MIB module uses the extended OBJECT-TYPE macro as
          --  defined in [13].


          --  this is the MIB module for ds1 objects

          ds1 OBJECT IDENTIFIER ::= { experimental 2 }

          -- the DS1 Configuration group




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          -- Although the objects in this group are read-only, at the
          -- agent's discretion they may be made read-write so that the
          -- management station, when appropriately authorized, may
          -- change the behavior of the CSU, e.g., to place the device
          -- into a loopback state or emit a QRSS BER test.

          -- Implementation of this group is mandatory for all systems
          -- that attach to a ds1.

          ds1ConfigTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF DS1ConfigEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "The DS1 Configuration table."
              ::= { ds1 1 }

          ds1ConfigEntry OBJECT-TYPE
              SYNTAX  DS1ConfigEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "An entry in the DS1 Configuration table."
              INDEX   { ds1CSUIndex }
              ::= { ds1ConfigTable 1 }

          DS1ConfigEntry ::=
              SEQUENCE {
                  ds1CSUIndex
                      INTEGER,
                  ds1Index
                      INTEGER,
                  ds1TimeElapsed
                      INTEGER (1..900),
                  ds1ValidIntervals
                      INTEGER (0..96),
                  ds1LineType
                      INTEGER,
                  ds1ZeroCoding
                      INTEGER,
                  ds1Loopback
                      INTEGER,
                  ds1SendCode
                      INTEGER,
                  ds1YellowAlarm
                      INTEGER,
                  ds1RedAlarm
                      INTEGER,



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                  ds1CircuitIdentifier
                      DisplayString (SIZE (0..255))
          }

          ds1CSUIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The index value which uniquely identifies the CSU
                      to which this entry is applicable."
              ::= { ds1ConfigEntry 1 }

          ds1Index OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "An index value that uniquely identifies an
                      interface to a ds1.  The interface identified by a
                      particular value of this index is the same
                      interface as identified by the same value an
                      ifIndex object instance."
              ::= { ds1ConfigEntry 2 }

          ds1TimeElapsed OBJECT-TYPE
              SYNTAX  INTEGER (1..900)
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of seconds that have elapsed since the
                      beginning of the current error-measurement period.
                      Any fraction is rounded up."
              ::= { ds1ConfigEntry 3 }

          ds1ValidIntervals OBJECT-TYPE
              SYNTAX  INTEGER (0..96)
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of previous intervals for which valid
                      data was collected.  The value will be 96 unless
                      the CSU device was brought online within the last
                      24 hours, in which case the value will be the
                      number of complete 15 minute intervals the CSU has
                      been online."
              ::= { ds1ConfigEntry 4 }




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          ds1LineType OBJECT-TYPE
              SYNTAX  INTEGER {
                          other(1),
                          ds1ESF(2),
                          ds1D4(3),
                          ds1ANSI-ESF(4),
                          ds1G704(5),
                          ds1G704-CRC(6)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This variable indicates the variety of DS1 Line
                      implementing this circuit.  The type of circuit
                      affects the number of bits per second that the
                      circuit can reasonably carry, as well as the
                      interpretation of the usage and error statistics.

                      The values, in sequence, describe:
                      TITLE:       SPECIFICATION:
                      ds1ESF        AT&T Extended SuperFrame DS1 [10]
                      ds1D4         AT&T D4 format DS1 [16], [17]
                      ds1ANSI-ESF   ANSI Extended SuperFrame format [14]
                      ds1G704       CCITT Recommendation G.704 [12]
                                      (section 2.1.3.2)
                      ds1G704-CRC   CCITT Recommendation G.704 [12]
                                      (section 2.1.3.1)
                      "
              ::= { ds1ConfigEntry 5 }

          ds1ZeroCoding OBJECT-TYPE
              SYNTAX  INTEGER {
                          ds1JammedBit(1),
                          ds1B8ZS(2),
                          ds1InvertedHDLC(3),
                          ds1HDB3(4),
                          ds1ZBTSI(5)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This variable describes the variety of Zero Code
                      Suppression used on the link, which in turn
                      affects a number of its characteristics.

                      ds1JammedBit refers the Jammed bit Zero Encoding,
                      in which the AT&T specification of at least one
                      pulse every 8 bit periods is literally implemented



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                      by forcing a pulse in bit 8 of each channel.
                      Thus, only seven bits per channel, or 1.344 Mbps,
                      is available for data.

                      ds1B8ZS refers to the use of a specified pattern
                      of normal bits and bipolar violations which are
                      used to replace a sequence of eight zero bits (see
                      [14]).  In this context, all eight bits in a
                      channel are technically available for data, but
                      care must be taken with D4 encoded data to avoid
                      having HDLC Flag streams imitate spurious Yellow
                      Alarm conditions.  Typically, one bit per frame is
                      ignored to force flag streams to rotate, thereby
                      avoiding this error type.  CCITT Recommendation
                      G.703 [11] may be referred to for further
                      definition of these.

                      ds1InvertedHDLC refers to the practice, common on
                      HDLC encoded DS1 data links, of inverting the data
                      between the serial interface chip and the CSU.
                      Since HDLC guarantees one zero every 6 bits in the
                      worst case, while the standards call for (in
                      effect) at least one pulse every eight, inverted
                      HDLC enjoys 4/24 one's density on the line, which
                      may improve the effective clock stability of a DS1
                      line.  As with B8ZS, all eight bits in a channel
                      are technically available for data, but care must
                      be taken with D4 encoded data to avoid having HDLC
                      Flag streams imitate spurious Yellow Alarm
                      conditions.  Typically, one bit per frame is
                      ignored to force flag streams to rotate, thereby
                      avoiding this error type.

                      ANSI Clear Channels may use ds1ZBTSI, or Zero Byte
                      Time Slot Interchange (see [14]).

                      G.704 links, with or without CRC, use ds1HDB3 (see
                      [11]).  "
              ::= { ds1ConfigEntry 6 }

          ds1Loopback OBJECT-TYPE
              SYNTAX  INTEGER {
                          ds1NoLoop(1),
                          ds1LocalLoopbackLocalSide(2),
                          ds1LocalLoopbackRemoteSide(3),
                          ds1RemoteLoopbackLocalSide(4),
                          ds1RemoteLoopbackRemoteSide(5)
                      }



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              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This variable represents the loopback state of
                      the CSU.  Devices supporting read/write access
                      should return badValue in response to a requested
                      loopback state that the CSU does not support.  The
                      values mean:

                      ds1NoLoop

                         Not in the loopback state.  A device that is
                         not capable of performing a loopback on either
                         interface shall always return this as it's
                         value.

                      ds1LocalLoopbackLocalSide

                         Signal received from the local side of the
                         device is looped back at the local connector
                         (eg, without involving the CSU).

                      ds1LocalLoopbackRemoteSide

                         Signal received from the local side of the
                         device is looped back at the remote connector
                         (eg, through the CSU).

                      ds1RemoteLoopbackLocalSide

                         Signal received from the remote side of the
                         device is looped back at the local connector
                         (eg, through the CSU).

                      ds1RemoteLoopbackRemoteSide

                         Signal received from the remote side of the
                         device is looped back at the remote connector
                         (eg, without involving the CSU)."
              ::= { ds1ConfigEntry 7 }

          ds1SendCode OBJECT-TYPE
              SYNTAX  INTEGER {
                          ds1OtherTest(1),
                          ds1SendNoCode(2),
                          ds1SendSetCode(3),
                          ds1SendResetCode(4),
                          ds1SendQRSS(5)



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                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                 "This variable indicates what type of code is
                 being sent across the DS1 circuit by the CSU.  The
                 values mean:

                 ds1SendNoCode    sending looped or normal data
                 ds1SendSetCode   sending a loopback request
                 ds1SendResetCode sending a loopback termination request
                 ds1SendQRSS      sending the BERT pattern described in
                                  ANSI T1.403-1989 section 5.6
                 ds1OtherTest     sending a different BERT/BLERT pattern,
                                  such as all zeroes, all ones, etc."
              ::= { ds1ConfigEntry 8 }

          ds1YellowAlarm OBJECT-TYPE
              SYNTAX  INTEGER {
                          ds1NoYellowAlarm (1),
                          ds1YellowAlarm (2)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This variable indicates if a Yellow Alarm
                      condition exists.

                      Note that G.704 interfaces do not support Yellow
                      Alarms.  Accordingly, such agents should return
                      the value ds1NoYellowAlarm."
              ::= { ds1ConfigEntry 9 }

          ds1RedAlarm OBJECT-TYPE
              SYNTAX  INTEGER {
                          ds1NoRedAlarm (1),
                          ds1RedAlarm (2)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This variable indicates if a Red Alarm condition
                      exists.

                      Note that G.704 interfaces do not support Red
                      Alarms.  Accordingly, such agents should return
                      the value ds1NoRedAlarm."
              ::= { ds1ConfigEntry 10 }



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          ds1CircuitIdentifier OBJECT-TYPE
              SYNTAX  DisplayString (SIZE (0..255))
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This variable contains the transmission vendor's
                      circuit identifier, for the purpose of
                      facilitating troubleshooting."
              ::= { ds1ConfigEntry 11 }


          -- the DS1 Interval group

          -- Implementation of this group is mandatory for all systems
          -- that attach to a ds1.

          -- It is recognized that some currently deployed CSUs do not
          -- record the entire set of statistics specified in this
          -- group.  Accordingly, some agents queried for these objects
          -- may treat these objects as having an ACCESS clause value
          -- of not-accessible.

          -- The DS1 Interval Table contains various statistics
          -- collected by each CSU over the previous 24 hours of
          -- operation.  The past 24 hours are broken into 96 completed
          -- 15 minute intervals.

          ds1IntervalTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF DS1IntervalEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "The DS1 Interval table."
              ::= { ds1 2 }

          ds1IntervalEntry OBJECT-TYPE
              SYNTAX  DS1IntervalEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "An entry in the DS1 Interval table."
              INDEX   { ds1IntervalIndex, ds1IntervalNumber }
              ::= { ds1IntervalTable 1 }

          DS1IntervalEntry ::=
              SEQUENCE {
                  ds1IntervalIndex
                      INTEGER,



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                  ds1IntervalNumber
                      INTEGER (1..96),
                  ds1IntervalESs
                      Counter,
                  ds1IntervalSESs
                      Counter,
                  ds1IntervalSEFSs
                      Counter,
                  ds1IntervalUASs
                      Counter,
                  ds1IntervalCSSs
                      Counter,
                  ds1IntervalBPVs
                      Counter,
                  ds1IntervalCVs
                      Counter
              }

          ds1IntervalIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The index value which uniquely identifies the CSU
                      to which this entry is applicable.  The interface
                      identified by a particular value of this index is
                      the same interface as identified by the same value
                      an ds1CSUIndex object instance."
              ::= { ds1IntervalEntry 1 }

          ds1IntervalNumber OBJECT-TYPE
              SYNTAX  INTEGER (1..96)
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "A number between 1 and 96, where 1 is the most
                      recently completed 15 minute interval and 96 is
                      the least recently completed 15 minute interval
                      (assuming that all 96 intervals are valid)."
              ::= { ds1IntervalEntry 2 }

          ds1IntervalESs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of Errored
                      Seconds, as defined by ANSI Draft Standard



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                      T1M1.3/90 - 027R2[15], encountered by a DS1 CSU
                      during one of the previous 96 fifteen minute
                      intervals."
              ::= { ds1IntervalEntry 3 }

          ds1IntervalSESs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Severely Errored Seconds, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU during one of the previous 96 fifteen
                      minute intervals."
              ::= { ds1IntervalEntry 4 }

          ds1IntervalSEFSs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Severely Errored Framing Seconds, as defined by
                      ANSI Draft Standard T1M1.3/90 - 027R2[15],
                      encountered by a DS1 CSU during one of the
                      previous 96 fifteen minute intervals."
              ::= { ds1IntervalEntry 5 }

          ds1IntervalUASs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Unavailable Seconds, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU during one of the previous 96 fifteen
                      minute intervals."
              ::= { ds1IntervalEntry 6 }

          ds1IntervalCSSs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Controlled Slip Seconds, as defined by ANSI Draft



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                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU during one of the previous 96 fifteen
                      minute intervals."
              ::= { ds1IntervalEntry 7 }

          ds1IntervalBPVs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of Bipolar
                      Violations, as defined by ANSI Draft Standard
                      T1M1.3/90 - 027R2[15], encountered by a DS1 CSU
                      during one of the previous 96 fifteen minute
                      intervals."
              ::= { ds1IntervalEntry 8 }

          ds1IntervalCVs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of Code
                      Violation Error Events, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU during one of the previous 96 fifteen
                      minute intervals.

                      Note that D4 and G.704 (section 2.1.3.2)
                      interfaces do not support Code Violation Error
                      Events.  Accordingly, such agents may treat this
                      object as having an ACCESS clause value of not-
                      accessible."
              ::= { ds1IntervalEntry 9 }


          -- the DS1 Current group

          -- Implementation of this group is mandatory for all systems
          -- that attach to a ds1.

          -- It is recognized that some currently deployed CSUs do not
          -- record the entire set of statistics specified in this
          -- group.  Accordingly, some agents queried for these objects
          -- may treat these objects as having an ACCESS clause value
          -- of not-accessible.

          -- The DS1 current table contains various statistics being



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          -- collected for the current 15 minute interval.

          ds1CurrentTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF DS1CurrentEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "The DS1 Current table."
              ::= { ds1 3 }

          ds1CurrentEntry OBJECT-TYPE
              SYNTAX  DS1CurrentEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "An entry in the DS1 Current table."
              INDEX   { ds1CurrentIndex }
              ::= { ds1CurrentTable 1 }

          DS1CurrentEntry ::=
              SEQUENCE {
                  ds1CurrentIndex
                      INTEGER,
                  ds1CurrentESs
                      Counter,
                  ds1CurrentSESs
                      Counter,
                  ds1CurrentSEFSs
                      Counter,
                  ds1CurrentUASs
                      Counter,
                  ds1CurrentCSSs
                      Counter,
                  ds1CurrentBPVs
                      Counter,
                  ds1CurrentCVs
                      Counter
              }

          ds1CurrentIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The index value which uniquely identifies the CSU
                      to which this entry is applicable.  The interface
                      identified by a particular value of this index is
                      the same interface as identified by the same value



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                      an ds1CSUIndex object instance."
              ::= { ds1CurrentEntry 1 }

          ds1CurrentESs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of Errored
                      Seconds, as defined by ANSI Draft Standard
                      T1M1.3/90 - 027R2[15], encountered by a DS1 CSU in
                      the current 15 minute interval."
              ::= { ds1CurrentEntry 2 }

          ds1CurrentSESs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Severely Errored Seconds, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU in the current 15 minute interval."
              ::= { ds1CurrentEntry 3 }

          ds1CurrentSEFSs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Severely Errored Framing Seconds, as defined by
                      ANSI Draft Standard T1M1.3/90 - 027R2[15],
                      encountered by a DS1 CSU in the current 15 minute
                      interval."
              ::= { ds1CurrentEntry 4 }

          ds1CurrentUASs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Unavailable Seconds, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU in the current 15 minute interval."
              ::= { ds1CurrentEntry 5 }




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          ds1CurrentCSSs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Controlled Slip Seconds, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU in the current 15 minute interval."
              ::= { ds1CurrentEntry 6 }

          ds1CurrentBPVs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of Bipolar
                      Violations, as defined by ANSI Draft Standard
                      T1M1.3/90 - 027R2[15], encountered by a DS1 CSU in
                      the current 15 minute interval."
              ::= { ds1CurrentEntry 7 }

          ds1CurrentCVs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of Code
                      Violation Error Events, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU in the current 15 minute interval.

                      Note that D4 and G.704 (section 2.1.3.2)
                      interfaces do not support Code Violation Error
                      Events.  Accordingly, such agents may treat this
                      object as having an ACCESS clause value of not-
                      accessible."
              ::= { ds1CurrentEntry 8 }


          -- the DS1 Total group

          -- Implementation of this group is mandatory for all systems
          -- that attach to a ds1.

          -- It is recognized that some currently deployed CSUs do not
          -- record the entire set of statistics specified in this
          -- group.  Accordingly, some agents queried for these objects



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          -- may treat these objects as having an ACCESS clause value
          -- of not-accessible.

          -- The DS1 Total Table contains the cumulative sum of the
          -- various statistics for the 24 hour interval preceding the
          -- first valid interval in the ds1CurrentTable.

          ds1TotalTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF DS1TotalEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "The DS1 Total table.  24 hour interval."
              ::= { ds1 4 }

          ds1TotalEntry OBJECT-TYPE
              SYNTAX  DS1TotalEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "An entry in the DS1 Total table."
              INDEX   { ds1TotalIndex }
              ::= { ds1TotalTable 1 }

          DS1TotalEntry ::=
              SEQUENCE {
                  ds1TotalIndex
                      INTEGER,
                  ds1TotalESs
                      Counter,
                  ds1TotalSESs
                      Counter,
                  ds1TotalSEFSs
                      Counter,
                  ds1TotalUASs
                      Counter,
                  ds1TotalCSSs
                      Counter,
                  ds1TotalBPVs
                      Counter,
                  ds1TotalCVs
                      Counter
              }

          ds1TotalIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory



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              DESCRIPTION
                      "The index value which uniquely identifies the CSU
                      to which this entry is applicable.  The interface
                      identified by a particular value of this index is
                      the same interface as identified by the same value
                      an ds1CSUIndex object instance."
              ::= { ds1TotalEntry 1 }

          ds1TotalESs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of Errored
                      Seconds, as defined by ANSI Draft Standard
                      T1M1.3/90 - 027R2[15], encountered by a DS1 CSU in
                      the previous 24 hour interval"
              ::= { ds1TotalEntry 2 }

          ds1TotalSESs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Severely Errored Seconds, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU in the previous 24 hour interval."
              ::= { ds1TotalEntry 3 }

          ds1TotalSEFSs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Severely Errored Framing Seconds, as defined by
                      ANSI Draft Standard T1M1.3/90 - 027R2[15],
                      encountered by a DS1 CSU in the previous 24 hour
                      interval."
              ::= { ds1TotalEntry 4 }

          ds1TotalUASs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of



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RFC 1232                 DS1 Interface Objects                  May 1991


                      Unavailable Seconds, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU in the previous 24 hour interval."
              ::= { ds1TotalEntry 5 }

          ds1TotalCSSs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of
                      Controlled Slip Seconds, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU in the previous 24 hour interval."
              ::= { ds1TotalEntry 6 }

          ds1TotalBPVs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of Bipolar
                      Violations, as defined by ANSI Draft Standard
                      T1M1.3/90 - 027R2[15], encountered by a DS1 CSU in
                      the previous 24 hour interval."
              ::= { ds1TotalEntry 7 }

          ds1TotalCVs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The counter associated with the number of Code
                      Violation Error Events, as defined by ANSI Draft
                      Standard T1M1.3/90 - 027R2[15], encountered by a
                      DS1 CSU in the previous 24 hour interval.

                      Note that D4 and G.704 (section 2.1.3.2)
                      interfaces do not support Code Violation Error
                      Events.  Accordingly, such agents may treat this
                      object as having an ACCESS clause value of not-
                      accessible."
              ::= { ds1TotalEntry 8 }


          -- the DS1 Fractional group

          -- Implementation of this group is mandatory for those



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RFC 1232                 DS1 Interface Objects                  May 1991


          -- systems utilizing a fractional DS1 capability


          -- The DS1 fractional table contains identifies which DS1
          -- channels associated with a CSU are being used to support a
          -- logical interface, i.e., an entry in the interfaces table
          -- from the Internet-standard MIB.  For Clear Channel
          -- implementations, exactly one ifTable entry corresponds to
          -- the CSU being managed.  In this very typical case, the
          -- variable ds1Index indicates the value of ifIndex which
          -- corresponds to the interface being supported by a
          -- particular CSU.

          -- However, for fractional DS1 implementations, the
          -- correspondent value of ds1Index is 0, and for each DS1
          -- channel supporting a logical interface, there is an entry
          -- in the DS1 fractional table which names a value for
          -- ifIndex.
          --
          --      For ds1ESF, ds1D4, and ds1ANSI-ESF, there are 24 legal
          --      channels, numbered 1 through 24.
          --
          --      For G.704, there are 32 legal channels, numbered 1
          --      through 32.  ds1G704 can carry user data in channels 2
          --      through 32, channel 1 being an overhead channel.
          --      ds1G704-CRC can carry user data in channels 2 through
          --      16 and 18 through 32, channels 1 and 17 being overhead
          --      channels.

          ds1FracTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF DS1FracEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "The DS1 Fractional table."
              ::= { ds1 5 }

          ds1FracEntry OBJECT-TYPE
              SYNTAX  DS1FracEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "An entry in the DS1 Fractional table."
              INDEX   { ds1FracIndex, ds1FracNumber }
              ::= { ds1FracTable 1 }

          DS1FracEntry ::=
              SEQUENCE {



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                  ds1FracIndex
                      INTEGER,
                  ds1FracNumber
                      INTEGER (1..32),
                  ds1FracIfIndex
                      INTEGER
              }

          ds1FracIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The index value which uniquely identifies the CSU
                      to which this entry is applicable.  The interface
                      identified by a particular value of this index is
                      the same interface as identified by the same value
                      an ds1CSUIndex object instance."
              ::= { ds1FracEntry 1 }

          ds1FracNumber OBJECT-TYPE
              SYNTAX  INTEGER (1..32)
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The channel number for this entry."
              ::= { ds1FracEntry 2 }

          ds1FracIfIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "An index value that uniquely identifies an
                      interface to a ds1.  The interface identified by a
                      particular value of this index is the same
                      interface as identified by the same value an
                      ifIndex object instance."
              ::= { ds1FracEntry 3 }

          END










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RFC 1232                 DS1 Interface Objects                  May 1991


6.  Acknowledgements

   This document was produced by the SNMP and the Transmission MIB
   Working Groups:

               Anne Ambler, Spider
               Karl Auerbach, Sun
               Fred Baker, ACC
               Ken Brinkerhoff
               Ron Broersma, NOSC
               Jack Brown, US Army
               Theodore Brunner, Bellcore
               Jeffrey Buffum, HP
               Jeffrey D. Case, UTK
               Chris Chiptasso, Spartacus
               Paul Ciarfella, DEC
               Bob Collet
               Tracy Cox, Bellcore
               James R. Davin, MIT-LCS
               Kurt Dobbins, Cabletron
               Nadya El-Afandi, Network Systems
               Gary Ellis, HP
               Fred Engle
               Mike Erlinger
               Richard Fox, Synoptics
               Karen Frisa, CMU
               Chris Gunner, DEC
               Ken Hibbard, Xylogics
               Ole Jacobsen, Interop
               Ken Jones
               Satish Joshi, Synoptics
               Frank Kastenholz, Racal-Interlan
               Shimshon Kaufman, Spartacus
               Jim Kinder, Fibercom
               Alex Koifman, BBN
               Christopher Kolb, PSI
               Cheryl Krupczak, NCR
               Peter Lin, Vitalink
               John Lunny, TWG
               Carl Malamud
               Keith McCloghrie, HLS
               Donna McMaster, David Systems
               Lynn Monsanto, Sun
               Dave Perkins, 3COM
               Jim Reinstedler, Ungerman Bass
               Anil Rijsinghani, DEC
               Kary Robertson
               Marshall T. Rose, PSI (chair)



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RFC 1232                 DS1 Interface Objects                  May 1991


               L. Michael Sabo, NCSC
               Jon Saperia, DEC
               John Seligson
               Fei Shu, NEC
               Sam Sjogren, TGV
               Mark Sleeper, Sparta
               Lance Sprung
               Mike St.Johns
               Bob Stewart, Xyplex
               Emil Sturniold
               Kaj Tesink, Bellcore
               Dean Throop, Data General
               Bill Townsend, Xylogics
               Maurice Turcotte
               Kannan Varadhou
               Sudhanshu Verma, HP
               Warren Vik, Interactive Systems
               David Waitzman, BBN
               Steve Waldbusser, CMU
               Dan Wintringhan
               David Wood
               Jeff Young, Cray Research

7.  References

   [1] Cerf, V., "IAB Recommendations for the Development of Internet
       Network Management Standards", RFC 1052, NRI, April 1988.

   [2] Cerf, V., "Report of the Second Ad Hoc Network Management Review
       Group", RFC 1109, NRI, August 1989.

   [3] Rose M., and K. McCloghrie, "Structure and Identification of
       Management Information for TCP/IP-based internets", RFC 1155,
       Performance Systems International, Hughes LAN Systems, May 1990.

   [4] McCloghrie K., and M. Rose, "Management Information Base for
       Network Management of TCP/IP-based internets", RFC 1156, Hughes
       LAN Systems, Performance Systems International, May 1990.

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

   [6] McCloghrie K., and M. Rose, Editors, "Management Information Base
       for Network Management of TCP/IP-based internets", RFC 1213,
       Performance Systems International, March 1991.




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RFC 1232                 DS1 Interface Objects                  May 1991


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

   [8] Information processing systems - Open Systems Interconnection -
       Specification of Basic Encoding Rules for Abstract Notation One
       (ASN.1), International Organization for Standardization,
       International Standard 8825, December 1987.

   [9] AT&T Information Systems, AT&T ESF DS1 Channel Service Unit
       User's Manual, 999-100-305, February 1988.

  [10] AT&T Technical Reference, Requirements for Interfacing Digital
       Terminal Equipment to Services Employing the Extended Superframe
       Format, Publication 54016, May 1988.

  [11] CCITT Specifications Volume III, Recommendation G.703,
       Physical/Electrical Characteristics of Hierarchical Digital
       Interfaces, July 1988.

  [12] CCITT Specifications Volume III, Recommendation G.704,
       Synchronous frame structures used at primary and secondary
       hierarchical levels, July 1988.

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

  [14] ANSI T1.403-1989 American National Standard for
       Telecommunications -- Carrier-to-Customer Installation -- DS1
       Metallic Interface.

  [15] ANSI T1M1.3/90 - 027R2 Draft Proposed Standard -- Description of
       Installation and Maintenance Parameters for Digital Circuits,
       Facilities, and Networks.

  [16] Bell System Techical Reference, Publication 62411, High Capacity
       Digital Service Channel Interface Specification, September 1983.

  [17] Bell System Technical Reference, Publication 43801, "Digital
       Channel Bank Requirements and Objectives", November 1982.

8.  Security Considerations

   Security issues are not discussed in this memo.





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RFC 1232                 DS1 Interface Objects                  May 1991


9.  Authors' Addresses

   Fred Baker
   Advanced Computer Communications, Inc.
   720 Santa Barbara Street
   Santa Barbara, California  93101

   Phone: (805) 963 9431

   EMail: fbaker@acc.com


   Christopher P. Kolb
   Performance Systems International, Inc.
   Reston International Center
   11800 Sunrise Valley Drive
   Suite 1100
   Reston, VA 22091

   Phone: (703) 620-6651

   EMail: kolb@psi.com





























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