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Services are interrupted upon XCE switching on the extended subrack on the OSN 3500

Publication Date:  2012-07-24 Views:  100 Downloads:  0

Issue Description

The PIU on the extended subrack reports a POWER_ABNORMAL alarm. (The actual import voltage is -60 V.) To remove the fault, the customer needs to re-configure the voltage monitor jumpers (J5 and J8) for the power supply of the XCE on the extended subrack (-48 V monitor by default), that is, to remove the caps from J5 and J8.

The customer first sets the jumpers of the currently standby XCE (in slot 60) and install the XCE board and cables. In this case, no exceptional alarm is reported.

The customer then performs an active/standby switching of the XCE boards. In this case, all services on the extended subrack are interrupted. About one minute later, the cross-connect board on the master subrack switches from 9 to 10. The services on the extended subrack recover.      

Alarm Information

The PIU on the extended subrack reports a POWER_ABNORMAL alarm due to the wrong settings of the jumpers on the XCE:

72636       77    POWER_ABNORMAL        MJ          end

      2007-6-8 8:35:29     2007-6-8 10:21:11    0x0f   0x00   0x01   0x01   0xff                        

72637       78    POWER_ABNORMAL        MJ          end   

 2007-6-8 8:35:29     2007-6-8 10:21:16    0x10   0x00   0x01   0x01   0xff 

The following alarms appear in order when the customer is configuring the jumpers on the standby XCE (in slot 60):

482895      60    BUS_ERR               MJ          end  

       2007-6-28 12:17:44   2007-6-28 12:20:8    0x13   0x01   0x80   0x01   0xff 

482896      60    BUS_ERR               MJ          end  

       2007-6-28 12:17:44   2007-6-28 12:20:8    0x14   0x02   0x80   0x01   0xff 

482897      60    BUS_ERR               MJ          end  

       2007-6-28 12:17:57   2007-6-28 12:20:8    0x11   0x01   0x80   0x01   0xff 

482898      60    BUS_ERR               MJ          end 

        2007-6-28 12:17:57   2007-6-28 12:20:8    0x12   0x02   0x80   0x01   0xff 

//The preceding lists the alarms after the cable is unplugged.

482900      60    BD_STATUS             MJ          end 

        2007-6-28 12:20:8    2007-6-28 12:20:55   0xff   0xff   0xff   0xff   0xff 

//The preceding is the alarm generated after the board is unplugged and plugged.

The following alarms are generated on the service boards upon the active/standby XCE switching:

482992      51    PLL_FAIL              MJ          end    

     2007-6-28 12:27:46   2007-6-28 12:28:33   0x01   0x00   0x01   0xff   0xff

482916      52    TU_AIS                MJ          end   

      2007-6-28 12:27:46   2007-6-28 12:28:28   0x01   0x00   0x03   0xff   0x01

The following alarm is generated on the cross-connect board on the master subrack :

483115      9     BUS_ERR               MJ          end  

       2007-6-28 12:28:31   2007-6-28 12:29:13   0x12   0x02   0x07   0x02   0xff      

Handling Process

The operation results show that the cable between slot 60 and slot 9 is faulty. Replace the cable and check the hardware interfaces.       

Root Cause

The analysis shows that the active board on the master subrack is board before XCE switching on the extended subrack. For this reason, the cable between slot 60 and slot 9 works as the working cable between the master and extended subracks upon the switching. However, the cross-connect board 9 on the master subrack receives a BUS_ERR alarm upon the switching. As a result, automatic switching occurs between the active and standby cross-connect boards on the master subrack. The services run on the cable between slot 60 and slot 10. The following black box shows the switching data (bb9):

bb9.log                               2007-6-28 12:28:28      

     Level:3, XcsXcpModule.cpp, Line:2553, XCP switch because

c BUS_ERR or service board report XCS board

The services recover upon the switching.      


Locate and analyze the fault based on the on-site operation, alarms, and black box.

In the engineering debugging stage, the field engineers should test the active/standby switching and ensure that all cables are operational.