One day there was SNCP switching in customer network, then there appeared many V5_VCAIS alarms in somePQ1 and PQM channels, but no TU_AIS alarm,
customer want to know the reason.
There are some conditions for V5_VCAIS alarm
1. There must be error code while SNCP, and the error code must be in V5 byte
2. The platform alarm queue has overflowed
3.There is V5_VCAIS alarm while SNCP switching and it is before TU_AIS
4.there is 2.5s filtrate for GSCC board alarm.
This problem can be explain as following:
While SNCP switching there was V5 error code, then the tributary board detect the V5_VCAIS and report it to main control board platform, because there was
problem of platform alarm queue has overflowed , so the alarms overflowed after reporting V5_VCAIS, then TU_AIS can't be reported, at the meantime because the
end time of V5_VCAIS has overflowed too, so the main frame can't receive the alarm end time for V5_VCAIS, so the TU_AIS detected by tributary board was by 2.5s
1.There is V5 error code while switching
2.The TU_AIS has been filtrated