Troubleshooting Tip: ULL Interfaces down after the update of FortiGate

To troubleshoot the issue of ULL interfaces being down after updating FortiGate to version 7.4.9, follow these steps:

Make sure to set FEC to ON in order to match the correct and accurate FEC value for Huawei switches.

This can be done by running the following command:

config system interface
    edit "x6"
        set vdom "Test"
        set type physical set mediatype sr
        set snmp-index 32
        set forward-error-correction cl91-rs-fec
        set speed 25000full
    next
end

Confirm whether the actually effective FEC is enabled or disabled by running the command:

diagnose hardware deviceinfo nic x6 | grep -i fec

Verify the configuration of the 25G interface and FEC on the other end's switch.

Supported FEC Modes (ULL Ports): 

Notes:

• Interfaces at both ends of a link must work in the same FEC mode; otherwise, the interfaces do not go up.
• If their FEC modes are different, configure the same FEC mode on the interfaces when they work in non-auto-negotiation mode.