Comment 9 for bug 1912844

I am not sure I have any definitivie answers but here are my thoughts.

Compare a VLAN device created with `ip link add`

ip link add link enp6s0 name enp6s0.100 type vlan id 100

cat /sys/class/net/enp6s0.100/uevent
DEVTYPE=vlan
INTERFACE=enp6s0.100
IFINDEX=3

To an OVS VLAN interface created with ovs-vsctl:

ovs-vsctl add-port br-ex vlan100 tag=200 -- set Interface vlan100 type=internal

cat /sys/class/net/br-ex.100/uevent
INTERFACE=br-ex.100
IFINDEX=7

I suspect this is down to the tooling. OVS is creating virtual devices so it may not be what `ip link` would create.

Could the `is_vlan` function check for the '.' followed by an integer which is the indication of a VLAN in all cases?