20026 Faulty Phase-Locked Loop of the Board Clock

Description

The board clock phase-lock loop is faulty.

Attribute

Alarm ID	Alarm Severity	Alarm Type
20026	Major	Fault

Parameters

ID	Name	Meaning
1	Subrack No.	Subrack No.
2	Slot No.	Slot No.
3	Cpu No.	CPU No.
4	PPL No.	The number of the phase-lock loop
5	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

The voice quality and data transmission are affected.

System Actions

Handling of the active board in the active/standby operation mode: Perform the switchover if the standby is ready for the operation.
Handling of the standby board in the active/standby operation mode: None.
Handling of the board in the Independent operation mode: None.

Possible Causes

As the probable causes vary for different types of boards, please specify the type of the board in advance by the subrack number and slot number where the board is located.

If the GEIUx or GOIUx is faulty:

The active GSCU stops the clock output from the backplane.
The transmission equipment or the transmission link is faulty.
The hardware of the board is faulty.

If the GTNU,GDPUC, or GSCU is faulty:

The hardware of the board is faulty.

Procedure

As the handling procedures vary for different types of boards, please specify the type of the board in advance by the subrack number and slot number where the board is located. If the GEIUx/GOIUx is faulty:
1. Check whether a correlated parent alarm occurs.
  Y=> Clear the parent alarm according to the corresponding handling suggestions. Check whether the alarm is cleared.
  
  N=> Go to b.
  
  Correlated parent alarm
  
  20016 Faulty 32 MHz Clock from the Backplane
  
  The parent alarm and the child alarm have the same Subrack No. and Slot No. in the alarm location information.
2. Check whether the PPL number of the faulty board is 1.
  Y => The PPL number is 1. Go to c.
  
  N => The PPL number is not 1. Go to e.
3. Check whether there is optical port alarm.
  Y => There is optical port alarm. Go to d.
  
  N => There is no optical port alarm. Go to g.
4. Clear the optical port alarm according to its relevant handling suggestions, and then check whether the phase-locked alarm of the board clock is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm persists. Go to g.
5. Check whether there is clock alarm with the active GSCU.
  Y => There is clock alarm. Go to f.
  
  N => There is no clock alarm. Go to g.
6. Clear the GSCU alarm by adhering to the its clock handling procedures, and then check whether the GEIUx/GOIUx alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm persists. Go to g.
7. Replace the board and wait until the board is successfully restarted. 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.
As the handling procedures vary for different types of boards, please specify the type of the board in advance by the subrack number and slot number where the board is located. If the GDPUC, GTNU, or GSCU is faulty:
1. Check whether a correlated parent alarm occurs.
  Y=> Clear the parent alarm according to the corresponding handling suggestions. Check whether the alarm is cleared.
  
  N=> Go to b.
  
  Correlated parent alarm
  
  20016 Faulty 32 MHz Clock from the Backplane
  
  The parent alarm and the child alarm have the same Subrack No. and Slot No. in the alarm location information.
2. Replace the board and wait until the board is successfully restarted. 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.