Troubleshooting Tip: AFBR-89BDDZ-FN1(QSFP 100G) module interface down in FortiSwitches without the correct forwarding Error Correction configuration

[mrudhramurthi]

Description	This article describes the case when the QSFP(100G module) - AFBR-89BDDZ-FN1 module interface is down in FortiSwitches without the correct Forwarding Error Correction configuration.
Scope	FortiGate and FortiSwitches.
Solution	AFBR-89BDDZ-FN1 modules used by FortiSwitches, the port will be down if the FEC status is incorrect. FS1E24########## # get switch modules summary port25 Portname State Type DMI Transceiver RX Vendor Part Number Serial Number __________ _______ _______ ___ ____________ ___ ________________ ________________ ______________ port25 ALARM QSFP-28 Y 100G-PM4-BiDi N/A +Fortinet AFBR-89BDDZ-FN1 AF2303N00UJ Scenario 1 - Standalone FortiSwitches: FortiSwitch1 (AFBR-89BDDZ-FN1) <--> (AFBR-89BDDZ-FN1) FortiSwitch2. On both FortiSwitches, configure the FEC status to detect by module. Configuration: On both FortiSwitches: config switch physical-port     edit port# ---> Port where the module is connected.         set fec-state detect-by-module end Scenario 2 - FortiSwitch managed by FortiGate: FortiGate( AFBR-89BDDZ-FN1) <--> (AFBR-89BDDZ-FN1) FortiSwitch. Disable the FEC on both sides if the firmware is below 7.4.2 on FortiGate. Starting in 7.4.2, the detect-by-module command will be available for managed FortiSwitches. Configuration: From FortiGate: config system interface     edit <interface> --> Interface where the module is connected.         set forward-error-correction disable end From Managed FortiSwitch: config switch-controller managed-switch     edit <switch S/N>         config port             edit port# ---> Port where the module is connected.                 set fec-state disable end If the issue still persists, reach out to the Fortinet TAC team. Related document: FortiSwitch - Compatible Transceivers matrix