Freebsd qinq

kldload ng_eiface
kldload ng_ether
kldload ng_vlan
kldload ng_socket
ifconfig vlan2101 create
ifconfig vlan2101 vlan 2101 vlandev igb1

ngctl mkpeer vlan2101: vlan lower downstream
ngctl name vlan2101:lower cvlan1
ngctl connect vlan2101: cvlan1: upper nomatch
ngctl mkpeer cvlan1: eiface vlan102 ether 
ngctl msg cvlan1: addfilter '{ vlan=102 hook="vlan102" }'
# the same mac address as for parent interface vlan2101
ifconfig ngeth0 link 00:0d:88:6e:05:9c
ifconfig ngeth0 1.1.1.1 netmask 255.255.255.0
ifconfig vlan2101 1.1.1.1 netmask 255.255.255.0
ifconfig ngeth0 name vlan102
ifconfig igb1 promisc