Explicit Congestion Notification (ECN) allows ECN enabled endpoints to notify each other when they are experiencing congestion. It is supported on the following FortiSwitch models: FS-3032E, FS-3032D, FS-1048E, FS-1048D, FS-5xxD series, and FS-4xxE series.
On the FortiGate unit that is managing the compatible FortiSwitch unit, ECN can be enabled for each class of service (CoS) queue to enable packet marking to drop eligible packets. The command is only available when the dropping policy is weighted random early detection. It is disabled by default.
config switch-controller qos queue-policy
set schedule round-robin
set rate-by kbps
set drop-policy weighted-random-early-detection
set ecn enable