ip link add name ${BRIDGE} type bridge vlan_default_pvid 420 vlan_protocol 802.1ad

I have been doing this, but what I’ve also been setting vlan_filtering to 1, so I think that’s what’s keeping this from working. Clarifying the terminology (s tags and c tags) should also help in future troubleshooting. Thanks.

The topology looks like this:

       VIRTUAL           |        PHYSICAL
-------------------------|------------------------- 
      1        2         3         4        5
[VN] --- [LB] --- [VS] --|-- [P1] --- [P2] --- [PN] 

Nodes: VN = virtual lab node LB = linux bridge (external connector) VS = VMWare vSwitch P1 = 1st physical switch P2 = 2nd physical switch PN = physical lab node

Links:

1: link between virtual lab node and linux bridge. Created and destroyed dynamically. I can’t control the settings of this link and connected interfaces. Virtual lab nodes are nested VMs running in QEMU.

2: Link between the linux bridge and vSwitch. The linux bridge resides on the CML controller node, which is a VM in ESXi. This link must be a trunk.

3 and 4: both trunks, one from vSwitch to 1st physical switch, the second between 1st physical switch and 2nd physical switch.

5: End of the dot1q tunnel. Outer tag is stripped and inner traffic (tagged or not) is passed to the second lab node