RFC1232

From RFC-Wiki

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.

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

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

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.

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.

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

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].

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.

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

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

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.

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
           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
           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.

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
      -- 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,
              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 }
      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
                  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)
                  }
          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)
                  }
          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 }
      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,
              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
                  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
                  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
      -- 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
                  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 }
      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
      -- 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
          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
                  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
      -- 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 {
              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

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)
           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

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.

[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.

Security Considerations

Security issues are not discussed in this memo.

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]