20090 Excessive E1/T1 Synchronization Failures in an Hour

Description

If the LOF which is not over the raising threshold of ALARM "Loss of E1/T1 Frames (LOF)" exceeds 40 times within one hour, this alarm is generated. If no LOF is detected within ten minutes, this alarm is cleared.

Attribute

Alarm ID	Alarm Severity	Alarm Type
20090	Major	Fault

Parameters

ID	Name	Meaning
1	Subrack No.	Subrack No.
2	Slot No.	Slot No.
3	Cpu No.	CPU No.
4	Port No.	The number of the port
5	Intermittence number	Frame out-of-sync intermittent times
6	Site No.	The IDs of all sites whose OMLs are on the faulty E1/T1. If BTS are cascade connected,a maximum of 4 sites are shown.Only Abis E1/T1 alarm has this parameter.
7	Site Name	The Names of all sites whose OMLs are on the faulty E1/T1. If BTS are cascade connected,a maximum of 4 sites are shown.Only Abis E1/T1 alarm has this parameter.
8	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 quality of associated services degrades.

System Actions

None.

Possible Causes

The subrack fails to be securely grounded.
The shielding layer of the cable connecting the BSC to the transmission equipment is damaged.
The transmission network is faulty.

Procedure

Check whether the subrack fails to be securely grounded.
Y => It fails to be securely grounded. Go to 2.

N => It is securely grounded. Go to 3.
Connect securely the grounding cable and check whether the alarm is cleared.
Y => The alarm is cleared. The alarm handling is complete.

N => The alarm persists. Go to 3.
Check whether the shielding layer of the cable connecting the BSC to the transmission equipment is damaged.
Y => The shielding layer is damaged. Go to 4.

N => The shielding layer is not damaged. Go to 5.
Replace the damaged cable and check whether the alarm is cleared.
Y => The alarm is cleared. The alarm handling is complete.

N => The alarm persists. Go to 5.
Ask maintenance engineers to check whether the transmission network fails.
Y => The transmission network fails. Ask maintenance engineers to rectify the fault. The alarm handling is complete.

N => The transmission network is functional. Please contact Huawei Customer Service Center.