When creating a VLAN sub-interface on a Fortville i40e DPDK VF, the data plane does not work properly. For Niantic (ixgbe) and Fortville (i40e) VFs, the code in dpdk/device.c configures the VF with VLAN filter offload through the rte_eth API.

For the i40e NIC this doesn't work as expected (we didn't test the ixgbe case). Apparently, enabling vlan filter offload overrides the VLAN strip offload setting to on. But the VLAN strip offload must be disabled for VPP VLAN sub-interfaces to work.

The i40e driver works correctly if the code is changed to not configure VLAN filtering for VLAN sub-interfaces.