[Problem Description]
Trigger Condition:
The data in the memory of the SSN1GSCC board is modified abnormally sometimes due to time sequence shortage of the memory.
Problem Phenomena:
The SCC board of the R6 or earlier versions resets continuously. Consequently, certain problems may occur sometimes. For example, the service fails to be configured or is interrupted in certain cases.
The SCC board earlier than the R7C02B017SP01 changes to the installation status sometimes when the memory becomes abnormal.
If the SCC board is of the R7C02B017SP01 or later versions, the memory becomes abnormal sometimes. When the memory becomes abnormal, the DBMS_ERROR alarm is reported.
The SCC board of a version earlier than the R8C02B01j version becomes abnormal sometimes. When the SCC board becomes abnormal, the OptiX OSN 3500 changes to the installation status, or the SCC board resets continuously.
The SCC board of the R8C02B01j or later versions becomes abnormal sometimes. When the SCC board becomes abnormal, the DBMS_ERROR alarm is reported.
[Cause Analysis]
Hardware:
The SSN1GSCC board is short of time sequence.
In certain cases, the SSN1GSCC boards delivered before October 2006 do not match the memories properly. Hence, the data in the memory is modified abnormally. Consequently, the SSN1GSCC board fails to work in normal state.
In October 2006, the time sequence of the memory on SSN1GSCC the boards is optimized, and the impedance of the resistor connected in series to the SDRAM clock is changed from 33 ohms to 0 ohms. As a result, the time sequence is optimized to a certain extent. The data in the memory, however, is still modified abnormally sometimes.
In August 2008, the SSN1GSCC VER.B version is replaced with the SSN1GSCC VER.E version. The SCC boards are directly mounted with the memories rather than using the memory bars that are purchased separately. In addition, the time sequence of the memory on the SCC boards is further optimized. The data in the memory, however, is still modified abnormally sometimes.
Software:
The software of the V100R007 or later versions is provided with the mechanism of checking database consistency to prevent abnormal database configuration caused by abnormal modification of the data in the memory. In this case, the database checksum can be checked to determine whether the database is abnormal.
The data in the memory is modified abnormally sometimes when the board is working, because the SSN1GSCC board is short of time sequence. Hence, the database is modified abnormally. After the SCC board resets and checks the database, the SCC board finds that the data in the database is incomplete and then changes to the installation status.
In the V100R008 or later versions, the OSP platform provides the function of backing up the database in a real-time and incremental manner to increase the data storing speed of an intelligent module. This function has high requirements for time sequence of the memory. If a board is short of time sequence, the data in the database is modified easily. In this case. The program changes to the infinite loop state. Consequently, the OptiX OSN 3500 resets.
[Impact and Risk]
The SCC board of the R6 or earlier versions resets continuously. Consequently, certain problems may occur sometimes. For example, the service fails to be configured or is interrupted in certain cases.
The SCC board earlier than the R7C02B017SP01 changes to the installation status sometimes when the memory becomes abnormal.
In the case of the R7C02B017SP01 or later versions, the memory of the OptiX OSN 3500 equipment fails sometimes. When the memory fails, the DBMS_ERROR alarm is reported.
The SCC board of a version earlier than the R8C02B01j version becomes abnormal sometimes. When the SCC board becomes abnormal, the OptiX OSN 3500 changes to the installation status, or the SCC board resets continuously.
