altq unfortunately queuing vlan traffic.

[Bruce M. Simpson]

I can't speak for ALTQ at the moment however I believe dummynet may work 
on vlan devices.

I was careful not to break this when rewriting ether_input() in 
-CURRENT, as ip_dn_check_rule() is always called any time ether_demux() 
is entered (regardless if ether_input() has been re-entered due to the 
presence of M_PROMISC on a given mbuf chain).

Regards,
BMS