Same VLAN on Multiiple Fortilink Interfaces

[claydawg]

I have a scenario where there are two different Fortilink interfaces on a FortiGate. I need to extend a particular VLAN from the gate to both Fortilink-managed switches. Unfortunately this requires me to require a VLAN sub-interface on each Fortilink interface. One has an IP address configured and the other is just 0.0.0.0/0. I assumed, maybe incorrectly, that this would just do 802.1q and pass layer-2 between interfaces but I also know this is a firewall and that sort of behavior may not work. Can anyone confirm if this is supported? If not, is the only solution to re-architect this and reconfigure for only a single Fortilink?

[sw2090]

It is common use that a vid is unique per interface. Its the same everywhere. If you need more lines you will need a switch. This can be a physical one next to your FGT or you could create a vswitch out of your fortilink ports on your FGT (which they already are by factory default AFAIR).Then just create a vlan interface on that switch and you can use your vlan on every fortilink port.

[sjoshi]

Creating VLAN sub-interfaces with the same VLAN ID on multiple FortiLink interfaces on a FortiGate is not supported. Each VLAN sub-interface must have a unique VLAN ID to avoid conflicts. To extend a particular VLAN to both FortiLink-managed switches, consider reconfiguring the network architecture to use a single FortiLink interface for the VLAN to ensure proper functionality and avoid potential issues with duplicate VLAN IDs on different interfaces.

[FrancoisBlanchon]

Hi claydawg,

I have the same question, but I cannot find any usefull answer unfortunately. So did you succeed to setup several Fortiswitch loops, each connected through its own fortilink with a same VLANID setup on each FLink (in order to have a same VLAN on several switch loops)? Actually I know that the VLANID tagging will not be the issue, but it is at the layer3 level that the question is. The layer 3 GW handled by FGT, will be only on one Flink only. Then my question is, should it work with policies between Flinks ? to make possible the communication between hosts from on switch loop 1 to VLAN GW, and the same from hosts on switch loop 2 ?
Insane for me to write this, hope I will never have to implement fortiswitches in large campus env.
thx for your feedback.