rfc1407.txt

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RFC 1407                       DS3/E3 MIB                   January 1993


            ifIndex (= dsx3IfIndex)                      dsx3LineIndex

                    1      Line#A     Network Side            1
                    2      Line#A     RouterSide              2
                    3      Line#B     Network Side            3
                    4      Line#B     RouterSide              4
                    5      Line#C     Network Side            5
                    6      Line#C     Router Side             6
                    7      Line#D     Network Side            7
                    8      Line#D     Router Side             8

3.2.  Objectives of this MIB Module

   There are numerous things that could be included in a MIB for DS3/E3
   signals: the management of multiplexors, CSUs, DSUs, and the like.
   The intent of this document is to facilitate the common management of
   all devices with DS3/E3 interfaces.  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 DS3/E3 devices that are currently
   deployed.

3.3.  DS3/E3 Terminology

   The terminology used in this document to describe error conditions on
   a DS3 interface as monitored by a DS3 device are based on the
   definitions from the ANSI T1M1.3/92-005R1 draft standard [12].  If
   the definition in this document does not match the definition in the
   ANSI T1M1.3/92-005R1 draft document, the implementer should follow
   the definition described in this document.

3.3.1.  Error Events

          Bipolar Violation (BPV) Error Event
            A bipolar violation error event, for B3ZS(HDB3)-coded
            signals, is the occurrence of a pulse of the same polarity
            as the previous pulse without being part of the zero
            substitution code, B3ZS(HDB3).  For B3ZS(HDB3)-coded
            signals, a bipolar violation error event may also include
            other error patterns such as:  three(four) or more
            consecutive zeros and incorrect polarity.

          Excessive Zeros (EXZ) Error Event
            An EXZ is the occurrence of any zero string length equal
            to or greater than 3 for B3ZS, or greater than 4 for HDB3.

          Line Coding Violation (LCV) Error Event
            This parameter is a count of both BPVs and EXZs
            occurring over the accumulation period.  An EXZ



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RFC 1407                       DS3/E3 MIB                   January 1993


            increments the LCV by one regardless of the length
            of the zero string.

          P-bit Coding Violation (PCV) Error Event
            For all DS3 applications, a coding violation error
            event is a P-bit
            Parity Error event.  A P-bit Parity Error event is the
            occurrence of a received P-bit code on the DS3 M-frame
            that is not identical to the corresponding locally-
            calculated code.

          C-bit Coding Violation (CCV) Error Event
            For C-bit Parity and SYNTRAN DS3 applications, this is
            the count of coding violations reported via the C-bits.
            For C-bit Parity, it is a count of CP-bit parity errors
            occurring in the accumulation interval.  For SYNTRAN, it
            is a count of CRC-9 errors occurring in the accumulation
            interval.

3.3.2.  Performance Parameters

   All performance parameters are accumulated in fifteen minute
   intervals and up to 96 intervals (24 hours worth) are kept by an
   agent.  Fewer than 96 intervals of data will be available if the
   agent has been restarted within the last 24 hours.  In addition,
   there is a rolling 24-hour total of each performance parameter.

   There is no requirement for an agent to ensure fixed relationship
   between the start of a fifteen minute interval and any wall clock;
   however some agents may align the fifteen minute intervals with
   quarter hours.

          Line Errored Seconds (LES)
            A Line Errored Second is a second in
            which one or more CVs occurred OR one or more LOS defects.

          P-bit Errored Seconds (PES)
            An PES is a second with one or more PCVs OR
            one or more Out of Frame defects OR a detected incoming AIS.
            This gauge is not incremented when UASs are counted.

          P-bit Severely Errored Seconds (PSES)
            A PSES is a second with 44 or more PCVs OR
            one or more Out of Frame defects OR a detected incoming AIS.
            This gauge is not incremented when UASs are counted.

          C-bit Errored Seconds (CES)
            An CES is a second with one or more CCVs OR



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RFC 1407                       DS3/E3 MIB                   January 1993


            one or more Out of Frame defects OR a detected incoming AIS.
            This count is only for the SYNTRAN and C-bit Parity DS3
            applications.  This gauge is not incremented when UASs are
            counted.

          C-bit Severely Errored Seconds (CSES)
            A CSES is a second with 44 or more CCVs OR
            one or more Out of Frame defects OR a detected incoming AIS.
            This count is only for the SYNTRAN and C-bit Parity DS3
            applications.  This gauge is not incremented when UASs
            are counted.

          Severely Errored Framing Seconds (SEFS)
            A SEFS is a second with one or more Out of Frame defects
            OR a detected incoming AIS.

          Unavailable Seconds (UAS)
            UAS are calculated by counting the number of seconds that
            the interface is unavailable.  The DS3 interface is said
            to be unavailable from the onset of 10 contiguous PSESs, or
            the onset of the condition leading to a failure (see Failure
            States).  If the condition leading to the failure was
            immediately preceded by one or more contiguous PSESs, then
            the DS3 interface unavailability starts from the onset of
            these PSESs.  Once unavailable, and if no failure is
            present, the DS3 interface becomes available at the onset
            of 10 contiguous seconds with no PSESs.  Once unavailable,
            and if a failure is present, the DS3 interface becomes
            available at the onset of 10 contiguous seconds with no
            PSESs, if the failure clearing time is less than
            or equal to 10 seconds.  If the failure clearing time is
            more than 10 seconds, the DS3 interface becomes available
            at the onset of 10 contiguous seconds with no PSESs, or
            the onset period leading to the successful clearing
            condition, whichever occurs later.  With respect to the
            DS3 error counts, all counters are incremented
            while the DS3 interface is deemed available.  While the
            interface is deemed unavailable, the only count that is
            incremented is UASs.

            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 PSES and UAS
            counters must be adjusted when the Unavailable Signal
            State is entered. Clearly, successive GETs of the
            affected dsx3IntervalPSESs and dsx3IntervalUASs objects
            will return differing values if the first GET occurs
            during the first few seconds of the window.  This is



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RFC 1407                       DS3/E3 MIB                   January 1993


            viewed as an unavoidable side-effect of selecting the
            presently defined managed objects as a basis for this
            memo.

3.3.3.  Performance Defects

          Failure States:
            The Remote Alarm Indication (RAI) failure, in SYNTRAN
            applications, is declared after detecting
            the Yellow Alarm Signal on the alarm channel.  See ANSI
            T1.107a-1990 [10].  The Remote Alarm Indication failure,
            in C-bit Parity DS3 applications, is declared
            as soon as the preqsence of either one or two alarm signals
            are detected on then Far End Alarm Channel.  See [10].
            The Remote Alarm Indication failure may also be declared
            after detecting the far-end SEF/AIS defect (aka yellow).
            The Remote Alarm Indication failure is cleared as soon as
            the presence of the any of the above alarms are removed.

            Also, the incoming failure state is declared when a defect
            persists for at least 2-10 seconds.  The defects are
            the following:  Loss of Signal (LOS), an Out of Frame (OOF)
            or an incoming Alarm Indication Signal (AIS).
            The Failure State is cleared when the defect is absent
            for less than or equal to 20 seconds.

          Far End SEF/AIS defect (aka yellow)
            A Far End SEF/AIS defect is the occurrence of the two X-bits
            in a M-frame set to zero.  The Far End SEF/AIS defect is
            terminated when the two X-bits in a M-frame are set to
            one.

          Out of Frame (OOF) defect
            A DS3 OOF defect is detected when any three or more errors
            in sixteen or fewer consecutive F-bits occur within a DS3
            M-frame.  An OOF defect may also be called a Severely
            Errored Frame (SEF) defect.  An OOF defect is cleared when
            reframe occurs.  A DS3 Loss of Frame (LOF) failure is
            declared when the DS3 OOF defect is consistent for 2 to 10
            seconds.  The DS3 OOF defect ends when reframe occurs.
            The DS3 LOF failure is cleared when the DS3 OOF
            defect is absent for 10 to 20 seconds.

            An E3 OOF defect is detected when four consecutive frame
            alignment signals have been incorrectly received in there
            predicted positions in an E3 signal. E3 frame alignment
            occurs when the presence of three consecutive frame
            alignment signals have been detected.



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RFC 1407                       DS3/E3 MIB                   January 1993


          Loss of Signal (LOS) defect
            The DS3 LOS defect is declared upon observing 175 +/- 75
            contiguous pulse positions with no pulses of either
            positive or negative polarity.
            The DS3 LOS defect is terminated upon observing an average
            pulse density of at least 33% over a period of 175 +/- 75
            contiguous pulse positions starting with the receipt of a
            pulse.

          Alarm Indication Signal (AIS) defect
            The DS3 AIS is framed with "stuck stuffing."  This implies
            that it has a valid M-subframe alignments bits, M-frame
            alignment bits, and P bits.  The information bits are set
            to a 1010... sequence, starting with a one (1) after each
            M-subframe alignment bit, M-frame alignment bit, X bit, P
            bit, and C bit.  The C bits are all set to zero giving
            what is called "stuck stuffing."  The X bits are set to
            one.  The DS3 AIS defect is declared after DS3 AIS is
            present in contiguous M-frames for a time equal to or
            greater than T, where 0.2 ms <= T <= 100 ms.
            The DS3 AIS defect is terminated after AIS is absent in
            contiguous M-frames for a time equal to or greater than T.

            The E3 binary content of the AIS is nominally a continuous
            stream of ones.  AIS detection and the application of
            consequent actions, should be completed within a time
            limit of 1 ms.

3.3.4.  Other Terms

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

















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RFC 1407                       DS3/E3 MIB                   January 1993


4.  Object Definitions

               RFC1407-MIB DEFINITIONS ::= BEGIN

               IMPORTS
                       Gauge
                               FROM RFC1155-SMI
                       DisplayString, transmission
                               FROM RFC1213-MIB
                       OBJECT-TYPE
                               FROM RFC-1212;

               -- This MIB module uses the extended OBJECT-TYPE macro
               -- as defined in RFC 1212.

                       ds3  OBJECT IDENTIFIER ::= { transmission 30 }


               -- The DS3/E3 Near End Group

               -- Implementation of this group is mandatory for all
               -- systems that attach to a DS3/E3 Interface.

               -- The DS3/E3 Near End Group consists of four tables:
               --    DS3/E3 Configuration
               --    DS3/E3 Current
               --    DS3/E3 Interval
               --    DS3/E3 Total

               -- the DS3/E3 Configuration

               dsx3ConfigTable OBJECT-TYPE
                   SYNTAX  SEQUENCE OF Dsx3ConfigEntry
                   ACCESS  not-accessible
                   STATUS  mandatory
                   DESCRIPTION
                           "The DS3/E3 Configuration table."
                  ::= { ds3 5 }

              dsx3ConfigEntry OBJECT-TYPE
                  SYNTAX  Dsx3ConfigEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "An entry in the DS3/E3 Configuration table."
                 INDEX   { dsx3LineIndex }
                 ::= { dsx3ConfigTable 1 }




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RFC 1407                       DS3/E3 MIB                   January 1993