[Bridge] IP address on physcial interface instead of bridge interface?

[Joakim Tjernlund]

Nicolas de Pesloüan <nicolas.2p.debian at free.fr> wrote on 2010/03/25 22:03:06:
>
> Joakim Tjernlund wrote:
> [...]
> >
> > Sorry but I could not find that discussion but it doesn't sound as
> > what I was after. Basically I want the eth0 I/F keeping its IP address
> > and take over the roll of the br0 I/F when it has an IP address.
>
> Can you please try to explain the reason why you would like the bridge members
> to have an IP,
> instead of the br0 interface ?

Sure, our app sometimes just uses eth0 as an normal eth I/F and in some
configs eth0 needs to be bridged with other I/Fs. Moving the IP address from eth0 to
the br0 I/F is painful once the system has booted. There are services already running
on eth0 then once a user decides he needs bridged system all services needs to be restarted.

>
> What is the expected result ? Until now, you described a solution (having an
> IP address on the
> bridge members), but not the real problem you are trying to solve.
>
> Basically, a bridge is a level 2 link between the bridge members. An IP
> address is not required for
> the bridge to provide L2 connectivity between the members. But, if the host
> hosting the bridge need
> to be able to send/receive packets to/from bridge members, then it use the br0
> interface. Using br0
> to send packets let the bridge decide on which members to forward each
> packets. Using br0 to receive
> packets allow you not to listen on every members at the same time. For this
> reason, it is normal to
> give an IP address to th br0 interface and to leave the bridge members without
> any IP address.

All true, but adding an interface that is already in use to a bridge and then moving your IP address
to the br0 I/F without loosing connectivity is hard, probably impossible, with the current
bridge impl.

       Jocke