802.1q bridged trunk with STP

[Andrew Thompson]

On Wed, Mar 07, 2007 at 03:06:10PM -0500, Corey Smith wrote:
> Please CC: me as I am off list.
> 
> I want to be able to create an 802.1q bridged trunk.  This is nice if
> you want layer 1 and 2 redundancy on an arbitrary number of logical
> networks with only two physical network interfaces.
> 
> ifconfig bridge18 inet 192.168.1.50/24 addm vlan18 stp vlan18 addm vlan118 \
>  stp vlan118 up
> ifconfig: unable to set bridge flags: Invalid argument
> 
> This works if you don't enable stp but gives the error above
> otherwise.  Without using spanning tree you can't actually plug it
> into your switch.
 
I believe that MST support is needed in order to use spanning tree with
vlans but do be honest I havnt looked too far into it. The stp code in
6.2-RELEASE explicitly does not allow stp to be enabled on a vlan and
people who have removed this check have reported that it does indeed not
work.

HEAD and 6-STABLE both now have RSTP support in it and MST is an
extension of RSTP so could be added with some work. I plan to do this
sometime this year but you are welcome to kick it off.


cheers,
Andrew