Description of the problem

A Huawei OSN3500 (version 5.21.18.50) device with an expansion subrack reports an RTC_FAIL alarm, and the main control board is replaced to handle the problem. After plugging in the new main control during the replacement process, the service on the expansion subrack is found to be partially interrupted, and the service is resumed after modifying the ID and sending the network management data to the new main control.

Alarm information

The corresponding services of the access-side network elements landed on this OSN3500 service report TU_AIS, and the interrupted services are all the services landed on the OSN3500 expansion subrack, and there is no alarm on the OSN3500 side.

Single board type	Function Block Type	Location Information2	Alarm Name	Alarm Recovery Type	Alarm Acknowledgement Type	Alarm Description
EOW	TEMP_OVER		TEMP_OVER	Automatic recovery	Manual Confirmation	Operating Temperature Over Limit
UXCSB	OTHER		TEMP_OVER	Auto Recovery	Manual Confirmation	Operating Temperature Over Limit
GSCC	OTHER		RTC_FAIL	Check Recovery	Manual Confirmation	Master RTC (Real Time Clock)Timing Failure Alarm
PD1	PPI		BIP_EXC	Auto recovery	Manual Confirmation	BIP Error Code Excess
R1SLQ1	RS		R_LOF	Auto Recovery	Manual Acknowledgement	Receive line side frame loss
PD1	PPI		BIP_EXC	Automatic recovery	Manual Confirmation	BIP Error Code Excess
N1SLQ1	RS		R_LOF	Auto Recovery	Manual Acknowledgement	Receive line side frame loss
PD1	PPI		BIP_EXC	Automatic recovery	Manual Confirmation	BIP Error Code Excess
N4EFS0	VCTRUNK		ALM_GFP_dLFD	Auto Recovery	Manual Confirmation	GFP out of step
N4EFS0	VC12		LP_UNEQ_VC12	Auto Recovery	Manual Confirmation	VC12 level low order channel signal not loaded
R1SLQ1	VC4		AU_AIS	Auto Recovery	Manual Acknowledgement	AU Alarm Indication

Processing

1, the customer sent back the operation log and business interruption when the dump alarms are analyzed, it can be determined that the master control replacement on the network management data download has been interrupted before.

2、Send the data to R&D for analysis.

3. The results of the analysis are as follows:

When OSN3500 replaces the main control board for a single master, if there is configuration information of the expansion subrack on the newly replaced main control board (that is, there is a logical configuration of XCE), the data about the expansion subrack of the new master will be actively sent down to the network element, which will lead to interruption of the service to the expansion subrack.

This feature is available for OSN3500 R6 version and later devices.

When replacing a master control board with this type of configuration, first synchronize the master and backup data of the master control board by inserting the new master in the spare master slot, then reverse the master and backup masters, and finally replace them.

Attached is the alarm and operation log of the service interruption: the ID of the replaced master control network element is 700, and the service interruption starts from Thu Feb 04 22:55:10 2010. You can combine the operation logs to determine the time point of business interruption, that is, before the completion of sending network management data after replacing the master control.

Root Cause

Huawei OSN3500 device features

Recommendations & Summary

When replacing OSN3500 devices with expansion subracks, if the version is R6 or R6 or above and the configuration is single-master, you should first synchronize the master and backup data of the master board by inserting the new master in the spare master slot, and then reverse the master and backup masters before replacing them.

The related technical information in this chapter and the SDH equipment troubleshooting process are collected and organized by Shenzhen Optical Transmission Network Technology Company Limited (www.opticaltrans.com), please retain! Our company specializes in the sale of Huawei SDH optical transmission equipment,SDH transmission equipment.