I have a bit of a mind bender here... If you bridge 2 VLANs together over ATM 1483 (with say a WS-X5161 card), does 1483 pass the Spanning Tree PDUs? Assuming it does, if I am bridging VLAN 100 on the local switch to VLAN 500 on the other end, how does spanning tree handle that? Thanks, Dan.