Console port of NE20 and Ethernet0/0/1 port must plug and connect the terminal, and then they can be used. Remove Console port cable and Ethernet0/0/1 port is automatically down. Plug it and Ethernet0/0/1 port recovers. Test other ports and the same problem occurs. Console port must be used, otherwise the port cannot be up.
1. Check installment environment of NE20 and the device is not normally grounded.
2. Re-install grounding cable of NE20 and the fault disappears.
The device is not grounded normally.
The grounding of the device is necessary.