802.1q – C-VID – Customer VLAN
802.1ad – S-VID – QinQ Service VLAN
Stacking Manually
ip link add link enp1s0 enp1s0.203 type vlan proto 802.1ad id 203
ip link add link enp1s0.203 enp1s0.303 type vlan proto 802.1q id 303
ip link add link enp1s0.203 enp1s0.303 type vlan proto 80
ip link set enp1s0.293 up
Debian Interfaces file
allow-hotplug enp1s0
iface enp1s0 inet dhcp
post-up ip link add link enp1s0 enp1s0.203 type vlan proto 802.1ad id 203
auto enp1s0.203
iface enp1s0.203 inet dhcp
post-up ip link add link enp1s0.203 enp1s0.303 type vlan proto 802.1q id 303
auto enp1s0.203.303
iface enp1s0.203.303 inet dhcp