20223 Loss of Received Signal Frames on the Optical Port (RLOF)

Description

The Loss of Received Signal Frames on the Optical Port (RLOF) alarm is generated when the optical port of the BSC interface board fails to detect the information on the frame head over a certain period of time.

Attribute

Alarm ID	Alarm Severity	Alarm Type
20223	Major	Fault

Parameters

ID	Name	Meaning
1	Subrack No.	Subrack No.
2	Slot No.	Slot No.
3	Cpu No.	CPU No.
4	Optical Interface No.	Optical interface No.
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 services carried on the optical port are disrupted.

System Actions

When the active interface board is faulty, an active/standby switchover is performed if the standby board allows a switchover. Otherwise, no handling is performed.
When the standby interface board is faulty, no handling is performed.
When the faulty interface board works in independent mode, no handling is performed.

Possible Causes

The clock is faulty.
The transmission line or transmission equipment is faulty.
The local BSC is faulty.
The peer NE is faulty.

Procedure

Check the clock parent alarms.
1. Log in to the LMT and then choose Alarm Maintenance > Browse Alarm. Check whether the following clock alarms are reported:
  20016 Faulty 32 MHz Clock from the Backplane
  
  20026 Faulty Phase-Locked Loop of the Board Clock
  
  20044 Unavailable Clock Source
  
  20322 Unavailable Current Clock Reference for GGCU
  
  Y => One of these alarms is reported. Go to b.
  
  N => None of these alarms is reported. Go to 2.
2. Rectify the fault and clear the alarm found in (a) 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. Go to 2.
Check the trunk parent alarms.
1. Log in to the LMT and then choose Alarm Maintenance > Browse Alarm. Check whether the following trunk alarm is reported:
  20222 Loss of Signals on the Optical Port (RLOS)
  
  Y => The alarm alarm is reported. Go to b.
  
  N => The alarm is not reported. Go to 3.
2. Rectify the fault and clear the alarm found in (a) 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. Go to 3.
Check the BSC interface board.
1. Perform a loopback on the optical port of the BSC interface board. Then, check whether the alarm is cleared.
  N => The alarm is cleared. The BSC interface board is normal. Go to 4.
  
  N => The alarm is not cleared. The BSC interface board is faulty. Go to b.
2. Reset the BSC interface board. Wait five to ten minutes. 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. Remove and then reinstall the BSC interface board. 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. Replace the BSC interface board. 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 the transmission alarms of the peer NE.
1. Check the type of the peer NE.
  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 GOIUT at the peer end reports the following alarms:
  20222 Loss of Signals on the Optical Port (RLOS)
  
  20223 Loss of Received Signal Frames on the Optical Port (RLOF)
  
  20249 Tributary Alarm Indication Signal (AIS)
  
  Y => One of these alarms is reported. Go to c.
  
  N => None of these alarms is reported. Contact Huawei Customer Service Center.
3. Rectify the fault and clear the alarm found in (b) 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.
4. Check whether the BTS reports the following alarms:
  4714 E1/T1 Local Alarm or other associated 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 and clear the alarm 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 and check whether the peer NE reports the alarms related to the transmission.
  Y => The peer NE reports an alarm related to the transmission. 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.