Technical Tip: Managed FortiSwitch default configuration of inter switch link fortilink trunk, mclag-icl fortilink trunk and FortiGate Fortilink trunk

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Description	This article describes the default interface configuration of the inter-switch link trunk, mclag-icl fortilink trunk and the FortiGate Fortilink trunk that the FortiSwitch forms automatically in a Managed FortiSwitch Network.
Scope	Managed FortiSwitch, FortiGate v7.2.x and above.
Solution	When FortiGate manages FortiSwitch(es), the FortiSwitches automatically create a trunk interface. Refer to the below example: Let's focus on the FortiSwitch that is directly connected to the FortiGate. Port1 is directly connected to FortiGate. FortiSwitch FortiGate fortilink trunk default configuration:: FortiSwitch# config switch trunk     edit "906CACDECE68-0"         set mode lacp-active <----- Depends if the FortiLinkinterface on FortiGate is configured LACP mode active.         set auto-isl 1         set isl-fortilink 1 <----- Depends on the neighbor-detect config on the FortiGate interface (LLDP or FortiLink).         set mclag enable   <----- Depends if the FortiSwitch is configured for MCLAG-ICL.         set members "port1"     next Note that this trunk name, lacp-mode and 'isl-fortilink' configuration depend on the FortiLink interface configuration on the Fortiate: FortiGate#config system interface     set fortilink-neighbor-detect lldp     set lacp-mode active end FortiSwitch-FortiGate fortilink trunk interface default configuration: native VLAN 4094, allowed VLANS all, stp disabled, edge port disabled, dhcp snooping trusted FortiSwitch# config switch interface     edit "906CACDECE68-0"         set native-vlan 4094         set allowed-vlans 1-4094         set dhcp-snooping trusted         set stp-state disabled         set edge-port disabled     end port37 is the inter-switch link to another FortiSwitch. FortiSwitch inter-switch link fortilink trunk default configuration: FortiSwitch# config switch trunk     edit "8EFTF18000726-0"         set mode lacp-active         set auto-isl 1         set mclag enable         set static-isl enable         set members "port37"     end FortiSwitch inter-switch link fortilink trunk interface default configuration:  native vlan 4094, allowed vlans all, stp enabled, edge port disabled, dhcp snooping trusted. FortiSwitch# config switch interface     edit "8EFTF18000726-0"         set native-vlan 4094         set allowed-vlans 1-4094         set dhcp-snooping trusted         set edge-port disabled         set stp-state enabled     end ports23 and 24 are part of MCLAG-ICL fortilink trunk. FortiSwitch MCLAG-ICL fortilink trunk default configuration: FortiSwitch# config switch trunk     edit "_FlInK1_ICL0_"         set mode lacp-active         set auto-isl 1         set mclag-icl enable         set members "port23" "port24"     end FortiSwitch MCLAG-ICL fortilink trunk interface default configuration:  native vlan 4094, allowed vlans all, stp enabled, edge port disabled, dhcp snooping trusted, igmp-snooping-flood-reports enable and mcast-snooping-flood-traffic enable. FortiSwitch# config switch interface     edit "_FlInK1_ICL0_"         set native-vlan 4094         set allowed-vlans 1-4094         set dhcp-snooping trusted         set edge-port disabled         set stp-state enabled         set igmp-snooping-flood-reports enable         set mcast-snooping-flood-traffic enable     end