Technical Note: Tracking physical interface status of an aggregate link

[fgilloteau_FTNT]

Description

This article presents a new feature that has been introduced in FortiOS 5.2 to allow the tracking of the number of physical interfaces UP in an aggregate link.

Solution

Configuration example:

FG1K5D-3 (AGGREGATE_LAN) # show
config system interface
    edit "AGGREGATE_LAN"
        set vdom "root"
        set ip 10.57.0.1 255.255.252.0
        set type aggregate
        set member "port5" "port6" "port7" "port8"
        set snmp-index 49
        set min-links 2
        set min-links-down administrative
    next
end

min-links: Minimum number of aggregated ports that must be UP for the LAG to stay UP.
min-links-down: Action to take when there are less than min-links active members.

* min-links-down action can be to set the port down operationally or administratively.
* By default the port will be taken down operationally

With the above configuration, if 3 physical ports of the LAG are down, the LAG will be set administratively DOWN.