[c-nsp] 802.1Q double tag on catalyst 3500 ?

[Chris Cappuccio]

Hey does anyone know how to pass double tagged packets on cisco 3548s ?

I have an Adtran TA 3000/SM2 that will generate double tagged packets for
ADSL2+ customers.  The double tagged packets generated by the TA 3000 are
received by the 3548 just fine and it will even pass them along other
vlan trunk ports.

I wanted to connect a router into a port on the 3548 that would talk with
only single level vlan tags.  It would send and receive packets with
just the inner tag and then the 3548 would add/remove the outer tag.  The
router port config on the catalyst would look like this:

int f0/27
 switch access vlan 67
 mtu 1504

The trunk ports are mtu 1508 (we also pass some mpls traffic over them)

I want to allow the device on f0/27 to send tagged packets which the
3548 would then add a vlan 67 tag to.  (67 is the outer tag and then i want
each dsl customer to have their own inner tag)

Unfortunately it looks like the 3548 simply drops tagged packets on an
access port.  They never seem to make it back to the adtran.  Any ideas?

Does anyone else do this sort of thing through this level of catalyst
switch?

Chris