21525 SCCP DSP Unreachable

Description

This alarm is generated if the handshake between the BSC and the MSC at the SCCP layer fails.

Attribute

Alarm ID	Alarm Severity	Alarm Type
21525	Critical	Fault

Parameters

ID	Name	Meaning
1	Dest Signaling Point Index	Record of a SCCP Sub System, which is automatically generated during the configuration
2	Net Indication	0=International,1=International Standby,2=National,3=National Standby
3	SCCP Dest Signaling Point Code	Code of the signaling point in the signaling network, which is specified when configuring data of the signaling point
4	Local Signaling Point Code	the signaling point in the signaling network, which is specified when configuring data of the signaling point
5	SubrackNo.	Logical subrack number of the GXPUM CPU where the alarm is reported
6	Slot No.	Logical slot number of the GXPUM CPU where the alarm is reported
7	CPU No.	Logical CPU number of the GXPUM CPU where the alarm is reported
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 signaling interaction and the services between the BSC and the MSC are disrupted.

System Actions

When detecting that the DSP is unreachable, the MTP3 layer repeatedly attempts to establish the MTP3 links to recover the MTP3 DSP. If the MTP3 DSP is restored to the reachable state, the MTP3 layer sends the SCCP layer a message, indicating that the MTP3 DSP is reachable. When the SCCP layer receives this message, the alarm is cleared.

Possible Causes

The data configurations of the BSC and of the MSC are incorrect.
The SCCP DSP is inhibited manually.
All the MTP3 links corresponding to the SCCP DSP are deactivated.
The BSC or MSC is reset.
The SCCP management subsystem of the MSC is faulty.
The transmission equipment or transmission link between the BSC and the MSC is faulty.
The signaling link between the BSC and the MSC is faulty.
The BSC board is faulty.

Procedure

Check the data configurations.
1. Check whether the data configurations of the SS7 signaling points of the BSC are the same as those of the MSC.
  Y => The data configurations of the SS7 signaling points are the same. Go to c.
  
  N => The data configurations of the SS7 signaling points are different. Go to b.
2. Ensure that the data configurations of the SS7 signaling points of the BSC are the same as those of the MSC. 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 data configurations of the SS7 signaling links of the BSC are the same as those of the MSC.
  Y => The data configurations of the SS7 signaling links are the same. Go to e.
  
  N => The data configurations of the SS7 signaling links are different. Go to d.
4. Ensure that the data configurations of the SS7 signaling links of the BSC are the same as those of the MSC. 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. Check whether the data configurations of the SS7 signaling links are consistent with the physical connections.
  Y => The data configurations of the SS7 signaling links are consistent with the physical connections. Go to 2.
  
  N => The data configurations of the SS7 signaling links are inconsistent with the physical connections. Go to f.
6. Ensure that the data configurations of the SS7 signaling links are consistent with the physical connections. 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 status of the SCCP DSP and of the MTP3 link.
1. Check whether the SCCP DSP is manually inhibited.
  Y => The SCCP DSP is manually inhibited. Go to b.
  
  N => The SCCP DSP is not manually inhibited. Go to c.
2. Uninhibit the SCCP DSP. 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 MTP3 link is deactivated.
  Y => The MTP3 link is deactivated. Go to d.
  
  N => The MTP3 link is not deactivated. Go to 3.
4. Activate the MTP3 link. 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 whether the BSC is reset.Inquire the maintenance engineers about whether the BSC is reset.
Y => The BSC is reset. The alarm handling is complete.

N => The BSC is not reset. Go to 4.
Log in to the LMT and then choose Alarm Maintenance > Browse Alarm. Check whether the alarm 21528 Remote SCCP Fault is reported.
Y => The alarm is reported. The SCCP management subsystem of the MSC is faulty. Contact the maintenance engineers of the MSC. The alarm handling is complete.

N => The alarm is not reported. Go to 5.
Check for the parent alarms.
NOTE:
The parent alarms have the DPC, OPC, Subrack No., and Slot No. as the child alarms.
1. Log in to the LMT and then choose Alarm Maintenance > Browse Alarm. Check whether the following parent alarms related to the communication at the MTP3 layer are reported.
  21501 MTP3 DSP Unreachable
  
  21503 MTP3 Link Unavailable
  
  21516 Route Transmission on the MTP3 Prohibited
  
  Y => Any of the previous alarms is reported. Go to b.
  
  N => None of the previous alarms is reported. Go to c.
2. Rectify the fault according to the 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 c.
3. Log in to the LMT and then choose Alarm Maintenance > Browse Alarm. Check whether the following alarms related to the communication at the MTP2 layer are reported.
  21514 MTP2 Link Service Disrupted
  
  Y => Any of the previous alarms is reported. Go to d.
  
  N => Neither of the previous alarms is reported. Go to e.
4. Rectify the fault according to the 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 e.
5. Check whether the parent alarms related to the trunk cables are reported by the A interface board.
  If the A interface board is the GEIUA/GFGUA, check whether the following parent alarms related to the trunk cables are reported.
  
  20081 Loss of E1/T1 Signals (LOS)
  
  20082 Loss of E1/T1 Frames (LOF)
  
  20083 Remote E1/T1 Alarm (RAI)
  
  20084 E1/T1 Alarm Indication Signal (AIS)
  
  20085 Loss of E1/T1 Multiframes (LOM)
  
  20086 E1/T1 Link Loopback
  
  20087 High BER over the E1/T1 Link
  
  If the A interface board is the GOIUA/GOGUA, check whether the following parent alarms related to the trunk cables are reported.
  
  20221 Loss of Clock on the Optical Port (RLOC)
  
  20222 Loss of Signals on the Optical Port (RLOS)
  
  20223 Loss of Received Signal Frames on the Optical Port (RLOF)
  
  20224 Out-of-Synchronization of Received Signal Frames on the Optical Port (ROOF)
  
  20226 Regenerator Section Signal Failure (RSF)
  
  20227 Regenerator Section Signal Deteriorated (RSD)
  
  20228 Multiplex Section Alarm Indication Signal (MAIS)
  
  20229 Multiplex Section Remote Defect Indication (MRDI)
  
  20230 Loopback on the Optical Port
  
  20231 Administration Unit Alarm Indication Signal (AUAIS)
  
  20232 Loss of Administration Unit Pointer (AULOP)
  
  20233 Service Unequipped on the High-Order Path of the Optical Port (HPUNEQ)
  
  20235 High-Order Path Signal Label Byte Mismatch (HPSLM)
  
  20236 High-Order Path Signal Failure (HPSF)
  
  20237 High-Order Path Signal Deteriorated (HPSD)
  
  20238 Remote Defect Indication on the High-Order Path of the Optical Port (HPRDI)
  
  20239 Loss of Tributary Unit Multi-frames (TULOM)
  
  20240 Tributary Unit Alarm Indication Signal (TUAIS)
  
  20241 Loss of Tributary Unit Pointer (TULOP)
  
  20242 Service Unequipped on the Lower-Order Path of the Optical Port (LPUNEQ)
  
  20244 Signal Flag Mismatch on the Low-Order Path of the Optical Port (LPSLM)
  
  20245 Low-Order Path Remote Failure Indicaton (LPRFI)
  
  20246 Low-Order Path Remote Defect Indication (LPRDI)
  
  20247 Tributary Unit Type Mismatch (TUSIZEERR)
  
  20248 Loss of Tributary Signals (LOS)
  
  20249 Tributary Alarm Indication Signal (AIS)
  
  20250 Loss of Tributary Frames (LOF)
  
  20251 Remote Alarm Indication over the Tributary (RAI)
  
  20254 Tributary Loopback Alarm
  
  20255 Optical Module Fault
  
  Y => Any of the previous alarms is reported. Go to f.
  
  N => None of the previous alarms is not reported. Go to 6.
6. Rectify the fault according to the 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 6.
Check the GXPUM, A interface board, and Ater interface board.
1. Check whether the GXPUM, A interface board, and Ater interface board report the alarm 21205 Board Fault.
  Y => The alarm is reported. Go to b.
  
  N => The alarm is not reported. Contact Huawei Customer Service Center.
2. Rectify the fault according to the 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.