Setting VLAN priority Bits

Hi All,

I am trying to set VLAN Tag as 16 bit value which has 12 bit VLAN ID and 3 bits priority using following command.

But the command returns following error:

ifconfig vlan0 vlan 4200 vlanif en0

ifconfig: SIOCSETVLAN: Invalid argument

If I give 12 bit value then it works i.e. any value less than 4096 is acceptable.

Can someone tell me, how can i set priority bits for vlan interface?

Regards

Ashish Mittal