How to identify the cause of network flooding using wireshark?

Hi wireshark experts, I am a new wireshark user. I find intermittent link down from 3:00am ~ 3:02am sometimes. I use Windows perfmon and I found the network flooding. Could you tell me how to identify the root cause using wireshark?

As you can see bytes total/sec on four 10GbE(screenshot 1) below, it went from 10MB/s to 140MB/s on four links at 3:00am and caused no buffers errors.(screenshot 2)

I check the output.zip and I know the packets/sec is increased at 3:02am but there is no suspicious IP address, please help. Check out the file in the wireshark directory. ftp://ftp01.quantatw.com/ user: sapftp password: wju123

Thanks for your help. Any ideas will be really appreciated.