So you can configure eth0 with vlan100:
VLAN=yes
VLAN_NAME_TYPE=VLAN_PLUS_VID_NO_PAD
DEVICE=vlan100
PHYSDEV=eth0
BOOTPROTO=static
ONBOOT=yes
TYPE=Ethernet
IPADDR=10.10.10.1
NETMASK=255.255.255.0
Now the interface will see traffic tagged with vlan 100.
I can configure Centos to forward vlan100 packets to where ever.
Now suppose I have multiple private vlans inside of vlan 100?
Vlan 103, vlan 104.
How would I get the interface to see the private vlans?