20956 Clock reference source from BackPlane fault alarm

Description

Abnormality in BackPlane 19M SDH Signal

Attribute

Alarm ID Alarm Severity Alarm Type
20956 Major Fault

Parameters

ID Name Meaning
1 Subrack No.

The number of the subrack

2 Slot No.

The number of the slot

3 CPU No.

The number of the CPU

4 Alarm Attribute

0=Normal, Alarms period are longer than the Transient Threshold.

1=Transient Count, The times and the period of the alarms whose periods are shorter than the Transient Threshold are summed up. If the sum result is longer than the Alarm Occurrence Period Threshold or Alarm Occurrence Times Threshold, an alarm so called Transient Count Alarm is triggered. Because Transient Count Alarm is based on accumulative result, the recovery of the alarm may occur at least one Summing Cycle later. The Summing Cycle can be query by MML "LST STATSLDWIN".

5 Cause Code

1=19M SDH Clock reference source from BackPlane,2=8k SDH Clock reference source from BackPlane,3=32M TDM Clock reference source from BackPlane,4=8k TDM Clock reference source from BackPlane

Impact on the System

This will interrupt services.

System Actions

None.

Possible Causes

  • (1) The input signal for clock reference is lost.
  • (2) The frequency offset of input signal for clock reference goes beyond the pull-in range.

Procedure

  1. (1) Check whether this alarm is generated by all the service boards in the subrack.

    Y => Go to Step (2).

    N => Go to Step (3).

    (2) The SCU is not inserted tightly.

    1)Insert the SCU tightly.

    2)Check whether the alarm is cleared.

    Y => The alarm handling is complete.

    N => Go to Step (3).

    (3) The service board is not inserted tightly.

    1)Insert the service board tightly.

    2)Check whether the alarm is cleared.

    Y => The alarm handling is complete.

    N => Go to Step (4).

    (4) The service board may be damaged.

    1)Replace the service board.

    2)Check whether the alarm is cleared.

    Y => The alarm handling is complete.

    N => Go to Step (5).

    (5) The mux board may be damaged.

    1)Replace the mux board.

    2)Check whether the alarm is cleared.

    Y => The alarm handling is complete.

    N => Go to Step (6).

    (6) The backplane may be damaged physically. Contact Huawei technical support.


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