rfc2496.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

          adjustments to the counters.  A way to do this is sketched in
          Appendix B.

          In any case, a linkDown trap shall be sent only after the
          agent has determined for certain that the unavailable state
          has been entered, but the time on the trap will be that of the
          first UAS (i.e., 10 seconds earlier).  A linkUp trap shall be
          handled similarly.

          According to ANSI T1.231 unavailable time begins at the
          _onset_ of 10 contiguous severely errored seconds -- that is,
          unavailable time starts with the _first_ of the 10 contiguous
          SESs.  Also, while an interface is deemed unavailable all
          counters for that interface are frozen except for the UAS
          count.  It follows that an implementation which strictly
          complies with this standard must _not_ increment any counters
          other than the UAS count -- even temporarily -- as a result of
          anything that happens during those 10 seconds.  Since changes
          in the signal state lag the data to which they apply by 10
          seconds, an ANSI-compliant implementation must pass the the
          one-second statistics through a 10-second delay line prior to
          updating any counters.  That can be done by performing the
          following steps at the end of each one second interval.

   i)   Read near/far end CV counter and alarm status flags from the
        hardware.

   ii)  Accumulate the CV counts for the preceding second and compare
        them to the ES and SES threshold for the layer in question.
        Update the signal state and shift the one-second CV counts and
        ES/SES flags into the 10-element delay line.  Note that far-end
        one-second statistics are to be flagged as "absent" during any
        second in which there is an incoming defect at the layer in
        question or at any lower layer.

   iii) Update the current interval statistics using the signal state
        from the _previous_ update cycle and the one-second CV counts
        and ES/SES flags shifted out of the 10-element delay line.

   This approach is further described in Appendix B.

2.4.3.  Performance Defects

     Failure States:
          The Remote Alarm Indication (RAI) failure, in SYNTRAN
          applications, is declared after detecting the Yellow Alarm



Fowler, Ed.                 Standards Track                    [Page 13]

RFC 2496                      DS3/E3 MIB                    January 1999


          Signal on the alarm channel.  See ANSI T1.107a-1990 [9a]. The
          Remote Alarm Indication failure, in C-bit Parity DS3
          applications, is declared as soon as the presence of either
          one or two alarm signals are detected on the Far End Alarm
          Channel.  See [9].  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.
          (Also known as SASCP-PFE. See T1.231 section 7.4.4.2.6)

     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. (See T1.231 section 7.1.2.2.1)

          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.

     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. (See T1.231 section 7.1.2.1.1)




Fowler, Ed.                 Standards Track                    [Page 14]

RFC 2496                      DS3/E3 MIB                    January 1999


     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.  (See T1.231 section 7.1.2.2.3)

          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.

2.4.4.  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.

     Proxy
          In this document, the word proxy is meant to indicate an
          application which receives SNMP messages and replies to them
          on behalf of the devices which implement the actual DS3/E3
          interfaces.  The proxy may have already collected the
          information about the DS3/E3 interfaces into its local
          database and may not necessarily forward the requests to the
          actual DS3/E3 interface.  It is expected in such an
          application that there are periods of time where the proxy is
          not communicating with the DS3/E3 interfaces.  In these
          instances the proxy will not necessarily have up-to-date
          configuration information and will most likely have missed the
          collection of some statistics data.  Missed statistics data
          collection will result in invalid data in the interval table.

3.  Object Definitions

     DS3-MIB DEFINITIONS ::= BEGIN

     IMPORTS
          MODULE-IDENTITY, OBJECT-TYPE,
          NOTIFICATION-TYPE, transmission         FROM SNMPv2-SMI



Fowler, Ed.                 Standards Track                    [Page 15]

RFC 2496                      DS3/E3 MIB                    January 1999


          DisplayString, TimeStamp, TruthValue    FROM SNMPv2-TC
          MODULE-COMPLIANCE, OBJECT-GROUP,
          NOTIFICATION-GROUP                      FROM SNMPv2-CONF
          InterfaceIndex                          FROM IF-MIB
          PerfCurrentCount, PerfIntervalCount,
          PerfTotalCount                          FROM PerfHist-TC-MIB;


     ds3 MODULE-IDENTITY
         LAST-UPDATED "9808012130Z"
         ORGANIZATION "IETF Trunk MIB Working Group"
         CONTACT-INFO
           "        David Fowler

            Postal: Newbridge Networks Corporation
                    600 March Road
                    Kanata, Ontario, Canada K2K 2E6

                    Tel: [phone]
                    Fax: [phone]

            E-mail: [e-mail]"
         DESCRIPTION
              "The is the MIB module that describes
               DS3 and E3 interfaces objects."

         ::= { transmission 30 }

     -- The DS3/E3 Near End Group

     -- 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 Table

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

     dsx3ConfigEntry OBJECT-TYPE
          SYNTAX  Dsx3ConfigEntry



Fowler, Ed.                 Standards Track                    [Page 16]

RFC 2496                      DS3/E3 MIB                    January 1999


          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "An entry in the DS3/E3 Configuration table."
          INDEX   { dsx3LineIndex }
          ::= { dsx3ConfigTable 1 }

     Dsx3ConfigEntry ::=
          SEQUENCE {
              dsx3LineIndex                        InterfaceIndex,
              dsx3IfIndex                          InterfaceIndex,
              dsx3TimeElapsed                      INTEGER,
              dsx3ValidIntervals                   INTEGER,
              dsx3LineType                         INTEGER,
              dsx3LineCoding                       INTEGER,
              dsx3SendCode                         INTEGER,
              dsx3CircuitIdentifier                DisplayString,
              dsx3LoopbackConfig                   INTEGER,
              dsx3LineStatus                       INTEGER,
              dsx3TransmitClockSource              INTEGER,
              dsx3InvalidIntervals                 INTEGER,
              dsx3LineLength                       INTEGER,
              dsx3LineStatusLastChange             TimeStamp,
              dsx3LineStatusChangeTrapEnable       INTEGER,
              dsx3LoopbackStatus                   INTEGER,
              dsx3Channelization                   INTEGER,
              dsx3Ds1ForRemoteLoop                 INTEGER
     }

     dsx3LineIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "This object should be made equal to ifIndex.  The
                 next paragraph describes its previous usage.
                 Making the object equal to ifIndex allows propoer
                 use of ifStackTable.

                 Previously, this object was the identifier of a
                 DS3/E3 Interface on a managed device.  If there is
                 an ifEntry that is directly associated with this
                 and only this DS3/E3 interface, it should have the
                 same value as ifIndex.  Otherwise, number the
                 dsx3LineIndices with an unique identifier
                 following the rules of choosing a number that is
                 greater than ifNumber and numbering the inside
                 interfaces (e.g., equipment side) with even



Fowler, Ed.                 Standards Track                    [Page 17]

RFC 2496                      DS3/E3 MIB                    January 1999


                 numbers and outside interfaces (e.g, network side)
                 with odd numbers."
          ::= { dsx3ConfigEntry 1 }

     dsx3IfIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  deprecated
          DESCRIPTION
                 "This value for this object is equal to the value
                 of ifIndex from the Interfaces table of MIB II
                 (RFC 1213)."
          ::= { dsx3ConfigEntry 2 }

     dsx3TimeElapsed OBJECT-TYPE
          SYNTAX  INTEGER (0..899)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of seconds that have elapsed since the
                 beginning of the near end current error-
                 measurement period.  If, for some reason, such as
                 an adjustment in the system's time-of-day clock,
                 the current interval exceeds the maximum value,
                 the agent will return the maximum value."

          ::= { dsx3ConfigEntry 3 }

     dsx3ValidIntervals OBJECT-TYPE
          SYNTAX  INTEGER (0..96)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of previous near end intervals for
                 which data was collected.  The value will be
                 96 unless the interface was brought online within
                 the last 24 hours, in which case the value will be
                 the number of complete 15 minute near end
                 intervals since the interface has been online.  In
                 the case where the agent is a proxy, it is
                 possible that some intervals are unavailable.  In
                 this case, this interval is the maximum interval
                 number for which data is available."
          ::= { dsx3ConfigEntry 4 }

     dsx3LineType OBJECT-TYPE
          SYNTAX  INTEGER {
                     dsx3other(1),



Fowler, Ed.                 Standards Track                    [Page 18]

RFC 2496                      DS3/E3 MIB                    January 1999


                     dsx3M23(2),
                     dsx3SYNTRAN(3),
                     dsx3CbitParity(4),
                     dsx3ClearChannel(5),
                     e3other(6),
                     e3Framed(7),