Re: [PATCH] bridge: flush forwarding table when device carrier off

[Stephen Hemminger <shemminger@osdl.org>]

On Thu, 12 Oct 2006 17:30:33 -0400
jamal <hadi@cyberus.ca> wrote:

> On Thu, 2006-12-10 at 16:10 -0400, Andy Gospodarek wrote:
> > On Thu, Oct 12, 2006 at 11:24:31AM -0700, Stephen Hemminger wrote:
> > > Flush the forwarding table when carrier is lost. This helps for
> > > availability because we don't want to forward to a downed device and
> > > new packets may come in on other links.
> > > 
> > > Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
> > > 
> > 
> > Stephen,
> > 
> > This is an excellent idea 
> 
> I am on the other extreme - this is problematic if you have a large
> table already learnt. Agrevate that with an unstable link and it gets a
> lot worse. Both of which dont sound unrealistic in say a wireless AP.

We don't support bridging wireless, that requires some NDS stuff that
isn't supported, and requires more softmac than the stack has.

> A more sane policy i have seen is a timer that flushes the table after a
> programmed period; this way you counter a flipflop-ing link.

That's already there.

> IOW, the best place is to have this in some user space daemon. If it has
> to be in the kernel, can you add a systcl to disable it?
> 

When RSTP is in userspace, it will do the flushing.

-- 
Stephen Hemminger <shemminger@osdl.org>