Technical Tip: Static ISL command on auto ISL trunks

Description

This article describes the importance of static ISL commands on auto ISL trunks.

Scope

FortiSwitch.

Solution

When using FortiSwitches managed by FortiLink, the equipment management uses VLAN 4094 and MSTP instance 15.

This change will avoid that. If there is any problem with instance 0, there will be intermittencies in the administration of the equipment.

To avoid these disconnections, it is advisable to enable static ISL on the self-negotiated trunks.

config switch trunk
    edit "S224EPTF18-----8"
        set static-isl enable 
    next
end

If there are any problems on instance 0 of STP, doing this will prevent the possibility of intermittencies in the administration of the equipment.

This can be done with the next FortiGate command, too.

diagnose switch-controller switch-recommendation fabric-lockdown-enable