20087 High BER over the E1/T1 Link

Description

This alarm is generated if the BSC detects that the bit error rate on the E1/T1 port is always greater than 5E-4 in one minute. This alarm is cleared if the BSC detects that the bit error rate on the E1/T1 port is always smaller than 1E-6 in one minute.

Attribute

Alarm ID	Alarm Severity	Alarm Type
20087	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	Bit Error Type	0=NO ERR,1=CRC,2=FAS,3=CRC and FAS,4=Code Violation,5=Code Violation and CRC,6=Code Violation and FAS,7=Code Violation and CRC and FAS
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

If the active board is faulty, the quality of services carried on the port of the board is degraded.
If the standby board is faulty, the services are not affected.

System Actions

None

Possible Causes

The link code of the port of the BSC interface board is inconsistent with that of the interface board of the peer NE.
The E1/T1 cable of the BSC interface board is connected improperly.
The clock source of the BSC and that of the peer equipment are different.
The BSC subracks are grounded improperly.
The transmission equipment or transmission link between the BSC and the peer equipment is faulty.

Procedure

Check the value of Bit Error Type in Location info.
1. Check whether the value of Bit Error Type in Location info includes Code Violation.
  Y => If the value of Bit Error Type includes Code Violation, Go to b.
  
  N => The value of Bit Error Type doesn't include Code Violation, Go to 2.
2. Check whether the link codes of the ports of both the BSC and the peer equipment are configured consistently.
  Y => The link codes are configured consistently. Go to 2.
  
  N => The link codes are configured inconsistently. Go to c.
3. Change the link code of the port of the peer equipment so that it is consistent with the link code of the port of the BSC. Then, check whether the alarm is cleared.
  NOTE:
  Once being set, the link code of the port of the BSC cannot be changed. Therefore, if the link code of the port of the BSC is different from the link code of the port of the peer NE, you can only change the link code of the port of the peer NE.
  
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm is not cleared. Go to 2.
Check the E1/T1 cable connected to the BSC interface board.
1. Check whether the E1/T1 cable connected to the BSC interface board is loosened or damaged.
  Y => If the E1/T1 cable is loosened, Go to b. If the E1/T1 cable is damaged, Go to c.
  
  N => The E1/T1 cable is properly connected. Go to 3.
2. Secure both ends of the E1/T1 cable. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm is not cleared. Go to c.
3. Replace the E1/T1 cable. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm is not cleared. Go to 3.
Check the clock configuration of the BSC.
1. According to the Subrack No. and Slot No. in the alarm location information, check whether the clock status of the BSC interface board is normal.
  Y => The clock status is normal. Go to 4.
  
  N => The clock status is not normal. Go to b.
2. Check whether the clock status of the GSCU (this GSCU is located in the same subrack as the board that reports the alarm) is normal.
  Y => The clock status is normal. Go to 4.
  
  N => The clock status is not normal. Go to c.
3. Secure the connectors at both ends of the Y-shaped clock signal cable of the GSCU, or remove and then reinstall the GSCU. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm is not cleared. Go to d.
4. Check whether the status of the BSC clock reference source is normal.
  Y => The status is normal. Go to 4.
  
  N => The status is not normal. Go to e.
5. Reconfigure the BSC clock by referring to the Initial Configuration Guide. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm is not cleared. Go to 4.
Check whether the BSC subrack is properly grounded.
1. Check whether the BSC subrack is properly grounded.
  Y => The BSC subrack is properly grounded. Go to 5.
  
  N => The BSC subrack is improperly grounded. Go to b.
2. Ground the BSC subrack properly. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm is not cleared. Contact Huawei Customer Service Center.
Check the transmission between the BSC and the peer NE.
1. Check whether the peer NE is the GMPS/GEPS/GTCS or the BTS.
  Y => If the peer NE is the GMPS/GEPS/GTCS, Go to b. If the peer NE is the BTS, Go to c.
  
  N => The peer NE is not the GMPS/GEPS/GTCS or the BTS. Go to f.
2. Check whether the peer GMPS/GEPS/GTCS reports the following alarms:
  20081 Loss of E1/T1 Signals (LOS)
  
  20082 Loss of E1/T1 Frames (LOF)
  
  20084 E1/T1 Alarm Indication Signal (AIS)
  
  Y => One of these alarms is reported. Rectify the fault according to the relevant alarm help. The alarm handling is complete.
  
  N => None of these alarms is reported. Contact Huawei Customer Service Center.
3. Query the BTS index according to the alarm location information.
4. Check whether the BTS reports the following alarms:
  4714 E1/T1 Local Alarm or other E1 local alarms
  
  4718 AIS Alarm or other AIS alarms
  
  Y => One of these alarms is reported. Go to e.
  
  N => None of these alarms is reported. Contact Huawei Customer Service Center.
5. Rectify the fault found in (d) according to the relevant alarm help. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm is not cleared. Contact Huawei Customer Service Center.
6. Contact the maintenance engineers of the peer NE. On the peer NE side, perform a loopback on the port towards the BSC. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The peer NE is faulty. Contact the maintenance engineers of the peer NE. The alarm handling is complete.
  
  N => The alarm is not cleared. Contact Huawei Customer Service Center.