On Mon, Oct 30, 2006 at 07:28:37AM -0800, Stephen Hemminger wrote:

quoted

Could somebody explain, why bridge uses minimal MAC of the attached devices?
It makes this address instable, variable during bridge life-cycle, which is 
not good for DHCP. For example, I want to attach multiple virtual devices to 
one physical. Then, I need to make sure that after each virtual device 
addition, bridge addr is not changed and still addr of the physical device.  
Why not to use MAC of the first attached device?

The bridge physical address is the minimum of all the attached devices.
This is done because the STP standard requires it.  You can reset it
to be the same as any of the attached devices. This will not cause a
problem unless using STP.

You can in fact use any MAC address.  The STP standard recommends using
the minimum address, as that is deterministic, and so it doesn't depend
on the order in which you enslave subdevices.