20521 Back Board Trunk's L2 Entry Failure

Description

Back board trunk group's L2 entry is fault

Attribute

Alarm ID Alarm Severity Alarm Type
20521 Major Fault

Parameters

ID Name Meaning
1 Subrack No.

Subrack No.
2 Slot No.

Slot No.
3 CPU No.

CPU No.
4 Trunk No.

Back board trunk group No.
5 Corresponding Slot No.

Corresponding Slot No.
6 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".

Impact on the System

Communications between L2 entry fault board and other boards will lose packets,or interrupt.

System Actions

  • Reset the board with L2 entry fault.
  • If the fault still can't be solved after reseting the board for serveral times,then the board will be isolated.

Possible Causes

  • Packets sended by the board are error.
  • Packets are changed during transfer.
  • Switch chip is fault.

Procedure

  1. The system automatically resets the board. Wait until the board is successfully loaded and restarted, and check whether the alarm is cleared.

    Y => The alarm is cleared. The alarm handling is complete.

    N => The alarm persists. Go to 2.

  2. Change the board, and check whether the alarm is cleared.

    Y =>The alarm is cleared. The alarm handling is complete.

    N =>The alarm persists. Please contact Huawei Customer Service Center.

Parent topic: BSC Alarm Reference
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