Creating vlan(4) pseudo-interface In QNX

I have one ethernet port and want to configure it as VLAN interface.

For this purpose, I need to create vlan(4) pseudo-interface so that I can associte that with my ethernet interface using following ifconfig command.

ifconfig en0 vlan 21 vlanif en0.21

Kindly help me I am urgently needing help on this front.

Additionally, Can we create it suing ifconfig en0.21 create command? although heklp says it can create pseudo-device and not pseudo-interface.