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



Transmission MIB Working Group                                  [Page 1]

RFC 1232                 DS1 Interface Objects                  May 1991


  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.



Transmission MIB Working Group                                  [Page 2]

RFC 1232                 DS1 Interface Objects                  May 1991


  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



Transmission MIB Working Group                                  [Page 3]

RFC 1232                 DS1 Interface Objects                  May 1991


  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



Transmission MIB Working Group                                  [Page 4]

RFC 1232                 DS1 Interface Objects                  May 1991


              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



Transmission MIB Working Group                                  [Page 5]

RFC 1232                 DS1 Interface Objects                  May 1991


              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




Transmission MIB Working Group                                  [Page 6]

RFC 1232                 DS1 Interface Objects                  May 1991


         -- 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,



Transmission MIB Working Group                                  [Page 7]

RFC 1232                 DS1 Interface Objects                  May 1991


                 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 }




Transmission MIB Working Group                                  [Page 8]

RFC 1232                 DS1 Interface Objects                  May 1991


         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



Transmission MIB Working Group                                  [Page 9]

RFC 1232                 DS1 Interface Objects                  May 1991


                     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)
                     }



Transmission MIB Working Group                                 [Page 10]

RFC 1232                 DS1 Interface Objects                  May 1991


             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)



Transmission MIB Working Group                                 [Page 11]

RFC 1232                 DS1 Interface Objects                  May 1991


                     }
             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 }



Transmission MIB Working Group                                 [Page 12]

RFC 1232                 DS1 Interface Objects                  May 1991


         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,



Transmission MIB Working Group                                 [Page 13]

RFC 1232                 DS1 Interface Objects                  May 1991


                 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



Transmission MIB Working Group                                 [Page 14]

RFC 1232                 DS1 Interface Objects                  May 1991


                     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



Transmission MIB Working Group                                 [Page 15]

RFC 1232                 DS1 Interface Objects                  May 1991


                     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



Transmission MIB Working Group                                 [Page 16]

RFC 1232                 DS1 Interface Objects                  May 1991


         -- 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



Transmission MIB Working Group                                 [Page 17]

RFC 1232                 DS1 Interface Objects                  May 1991


                     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 }




Transmission MIB Working Group                                 [Page 18]

RFC 1232                 DS1 Interface Objects                  May 1991


         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



Transmission MIB Working Group                                 [Page 19]

RFC 1232                 DS1 Interface Objects                  May 1991


         -- 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



Transmission MIB Working Group                                 [Page 20]

RFC 1232                 DS1 Interface Objects                  May 1991


             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



Transmission MIB Working Group                                 [Page 21]

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



Transmission MIB Working Group                                 [Page 22]

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 {



Transmission MIB Working Group                                 [Page 23]

RFC 1232                 DS1 Interface Objects                  May 1991


                 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










Transmission MIB Working Group                                 [Page 24]

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)



Transmission MIB Working Group                                 [Page 25]

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.




Transmission MIB Working Group                                 [Page 26]

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.





Transmission MIB Working Group                                 [Page 27]

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: [email protected]


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

  Phone: (703) 620-6651

  EMail: [email protected]





























Transmission MIB Working Group                                 [Page 28]