There is EFT8 installed OSN3500 and Port1, Port2 carry Ethernet traffic.
One day, due to a particular problem, customer reset EFT8, then all service carried by this board went down.
There is no any abnormal alarm on EFT8 board, even whole OSN3500.
1, Check the configuartion by T2000, the MTU of Port1 and Port2 is 1535, the others are disabled.
2, Set the MTU to be radom value, then set it to be 1535 again, the service restored.
3, To prevent such problem happens again, set the MTU of Port8 to be 1535.
This problem is caused by that all the ports of the SSN1EFT8 share the same MTU. Once set the MTU of any port of the SSN1EFT8, the MTU of all the ports will
changed accordingly. When the SSN1EFT8 board reset, the GSCC will set the MTU of PORT8 at last, so the MTU of all the ports of SSN1EFT8 will changed to the
same value as PORT8.
The default MTU is 1522 even the Port is disabled.
This defect conforms EFT8 and EFTA.
To evade such problem, you can set the MTU of Port8 to be 1535.