QinQ not working

[bluebit]

I am having some issues getting QinQ working on a couple switches. I've read through a lot of the posts on here and from what I could gather this configuration should work. Any ideas?

Bldg A (WS-8) > Tower Switch (WS-12) > Bldg B (WS-8) - using VLAN 200 to move customer traffic across the switches, this is just for L2 connectivity for the customer from Bldg A to B. Customer wants to pass vlans across this link between buildings, so QinQ made sense to be able to accomplish this.

Bldg A: Ports 1 & 2 (siklu and backup link to tower, using STP) tagged VLAN 200, with port 8 (customer demarc) set to Q.
Tower Switch: Port 1 (Siklu to Bldg B), Port 2 and 3 (siklu and backup link to Bldg A) all tagged VLAN 200.
Bldg B: Port 1 (Siklu to tower) tagged VLAN 200, Port 8 (customer demarc) set to Q.

Is there anything I am missing? From what I could gather on the forums a T allows double-tags to flow through, and the Q on the ends should either strip or add the inner tag.

[bluebit]

Photos of VLAN Config attached. Running Version 1.5.0 on all three switches.

[mike99]

Seem right to me.

MTU settings ? QinQ add 4 bytes.

Do you have an IP address on VLAN 200 for building A and building B ? If so, can those ping each other ?

Try with untag (U instead of Q) at each customer demarc to see if VLAN flow through. QinQ should beavior the same with untag frames but also allow tagged frame to also pass through.

[bluebit]

MTU is 1528.
We do not have any IP address on VLAN 200, however, the customer was able to use untagged traffic between the buildings so we know that it works for that, but none of the tagged packets they are trying to send across will work (U or Q)

[mike99]

If untag paquet flow with U, tagged packet should flow with Q. Any drop on ports ?

If so, try higher MTU (1532).