Virtualization mode versus Aggregation mode — VLAN tags in packet_in messages

There is a difference in the packet_in messages that are sent to the OpenFlow controller by the switch based on the mode that the OpenFlow instance is operating in. In Virtualization mode, no VLAN tags are sent in packet_in messages sent to the OpenFlow controller. Even if the packets that came into the switch on the OpenFlow instance had VLAN tags, the switch in packet_in messages sent to the controller removes the tags. Flows that match on VLAN PCP or modify VLAN PCP are not supported in Virtualization mode. Any tagged packets that are received in Virtualization mode may have their PCP modified to default. VLAN PCP is not matched because tag is always stripped in Virtualization mode.

In Aggregate mode, the switch always sends VLAN tags in packet_in messages sent to the OpenFlow controller. Even if the packets that came in to the switch on the OpenFlow instance did not have VLAN tags, the switch adds them in packet_in messages sent to the controller. The switch adds a VLAN tag either based on the tag that the packet already carried when it came in to the switch or based on the membership of the port that the packet came in to the switch.