CAPWAP mode do not perform well as desired on low-end FortiGate devices. VLAN mode has been introduced to improve performance. FortiExtender in VALN mode is also managed by FortiGate in the same way as CAPWAP mode, but it uses VLAN to forward traffic between FortiGate and FortiExtender.
The VLAN interface is created automatically on FortiExtender. You cannot edit it or remove it.
config system interface
set type vlan
set vid 100
set ingress-intf lan
Just like CAPWAP mode, Virtual Wire Pair Configurations of the virtual wire pair are created automatically. You cannot edit it or remove it. These configurations specify the mapping of the LTE interfaces and the VLAN interfaces.
config system virtual-wire-pair
set lte1-mapping vlan1