[VLAN] Bridging and 802.1q - no fly?

[Mike Ireton]

Hello,

    So it seems to me that using 802.1q as an end station or router 
connected to 802.1q trunk ports is totally fine and I've used it for 
years and years now that way. Recently however I have begun to 
experament with bridging 802.1q ports together and I've had a lot less 
sucess than I thought I would.

    The specfic issues were when trying to run linux bridge code across 
linux 802.1q interfaces. In the first scenario, if I bridged two eth 
ports together and then added them to a bridge group, the STP 
announcements appeared to be misaligned in the frame by 4 bytes (the mac 
addresses of captured packets had unrecognisable garbage in the first 
four, then the begining of the correct address in the remainder). In the 
second scenario, if I create a vlan device (say vlan10) on two linux 
boxes and then add these interfaces to a bridge group, again, stp seems 
to malfunction - because it's not apparently getting tagged by 1q.

    Yes I have some patches in place like ebtables and bridge-nf and I'm 
aware there can be unfortunate interactions here. What I'd like to know 
however, is bridging the 1q interfaces considered legit and has another 
ever done this sucessfully? If so, what was your configuration?

Mike-