ConnectX-4 Double-tagging and QinQ

per instruction from

It shows ConnectX-4 support double-tagging, that makes me think it is QinQ. For the instruction, it shows example that, host OS VF has vlan 100, and guest OS has a vlan 40 interface. That makes me think it is QinQ. The packet from the VF should have two tags, 100 and 40. However, if I configure it like this, no packet sent out. but if i send packet from non-vlan link of the guest os, i can see the packet sent out from host with vlan100 tagged.

Is this a problem ? Does ConnectX-4 support QinQ ? or my firmware needs to be upgraded ?

driver: mlx5_core

version: 5.0-0

firmware-version: 14.24.1000 (MT_2470111034)


bus-info: 0000:3b:00.1

supports-statistics: yes

supports-test: yes

supports-eeprom-access: no

supports-register-dump: no

supports-priv-flags: yes

Hi Mike ,

Can you review the below and check if it works ?

ConnectX-4 and ConnectX-4 Lx adapter cards support 802.1Q double-tagging (C-tag stack- ing on C-tag)



Hi Samer,

Thanks for your information.

Yes, I did see the two articles. So that’s why i asked the question here.

The first page is for ConnectX-3 Pro and ConnectX-5, that is what i want to do for ConnectX-4.

The 2nd page is for ConnectX-4 , which mentions Double-Tagging , and similar as QiniQ for ConnectX-3 pro, however, i cannot get the expected result by following the instruction of this page. The expected result is that, we can see a packet with two tags 100(from Host VF) and 40 (from guest OS link). However, i cannot see the packet is sent out from the host.



Hi Mike,

For deep debug could you please open a support case at

as i see you have a valid support contract.



Hi Samer,

Sure, Thanks for your comment.