20251 Remote Alarm Indication over the Tributary (RAI)

Description

The alarm is generated when the tributary of the optical port of the BSC interface board receives the Remote Alarm Indication over the Tributary (RAI) signals from the peer equipment.

Attribute

Alarm ID	Alarm Severity	Alarm Type
20251	Major	Fault

Parameters

ID	Name	Meaning
1	Subrack No.	Subrack No.
2	Slot No.	Slot No.
3	Cpu No.	CPU No.
4	Tributary Unit No.	0 - 62(for E1 mode), 0 - 83(for T1 mode).
5	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.
6	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.
7	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 tributary of the optical port are disrupted.

System Actions

If the APS function is enabled on the interface board, no handling is performed.

If the APS function is disabled on the interface board, the handling varies with the operation modes of the board.

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 data configurations of the local optical port on the BSC side and the peer port are inconsistent.
The optical cable is improperly connected to the BSC.
The transmission line or transmission equipment is faulty.
The local interface board on the BSC side is faulty.
The peer NE is faulty.

Procedure

Check the data configuration of the optical port of the BSC interface board.
1. Check whether the frame formats of the optical port of the BSC interface board and that of the peer NE are consistent.
  Y => The frame formats are consistent. Go to 2.
  N => The frame formats are inconsistent. Go to b.
2. Modify the data configuration. 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 optical cable between the BSC interface board and the peer equipment.
1. Check whether the optical cable between the BSC and the peer equipment is correctly connected.
  Y => The optical cable between the BSC and the peer equipment is correctly connected. Go to c.
  
  N => The optical cable between the BSC and the peer equipment is incorrectly connected. Go to b.
2. Connect the TX and RX ends of the optical cable correctly. 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. Check whether the optical connector is loosened, detached, or dirty, and check whether the optical cable is damaged.
  Y => If the optical connector is loosened or detached, Go to d. If the optical connector is dirty, Go to e. If the optical cable is damaged, Go to f.
  N => If the optical connector is correctly connected, Go to 3.
4. Secure the optical connectors at the TX and RX ends. 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 e.
5. Remove the optical connectors and use the absorbent cotton saturated with the absolute alcohol to clean the connectors. Reinsert the connectors, and 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 f.
6. Replace the optical cable connected to 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 3.
Check the BSC interface board.
1. Identify the first connection point (such as the ODF) connected to the BSC and perform a loopback on the TX and RX of the BSC. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. Both the BSC interface board and the optical cable connected to the BSC interface board are normal. Reconnect the optical port, and Go to 4.
  N => The alarm is not cleared. The BSC interface board or the optical cable connected to the BSC interface board is faulty. Go to b.
2. Perform a loopback on the optical port of the BSC interface board. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The optical cable connected to the BSC interface board is faulty. Go to c.
  N => The alarm is not cleared. The BSC interface board is faulty. Go to d.
3. Replace the optical cable connected to 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.
4. Remove and then install 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 e.
5. 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 whether the peer NE reports the alarms related to the transmission.
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 d.
  N => The peer NE is not the GMPS/GEPS/GTCS or the BTS. Go to f.
2. Check whether the GOUIT of the peer NE reports the following alarms:
  20222 Loss of Signals on the Optical Port (RLOS)
  20223 Loss of Received Signal Frames on the Optical Port (RLOF)
  20228 Multiplex Section Alarm Indication Signal (MAIS)
  20248 Loss of Tributary Signals (LOS)
  20249 Tributary Alarm Indication Signal (AIS)
  20250 Loss of Tributary Frames (LOF)
  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 founding 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. Query the BTS information according to the alarm location information.
5. 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 f.
  N => None of these alarms is reported. Contact Huawei Customer Service Center.
6. Rectify the fault and clear the alarm founding in (e) 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.
7. 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 the alarms related to the transmission. Rectify the fault according to the relevant alarm help. The alarm handling is complete.
  N => The peer NE does not report the alarms related to the transmission.Contact Huawei Customer Service Center.