[Bridge] jumpstart stp port to forwarding state

[richardvoigt at gmail.com]

On 7/5/07, Leigh Sharpe <lsharpe at pacificwireless.com.au> wrote:
>
>  brctl setfd br0 0
>
> Sets the forwarding delay on the bridge to 0, making it forward
> immediately, instead of going into 'learning' mode. This affects the enti=
re
> bridge, not just a single port.
>


Thanks for the suggestions.  I already reduced it to 1, but was wary of
trying 0.

Would that make spanning tree flap?  Or is there still some hysteresis loop
allowing it to stabilize?

We have a transparent traffic shaper which sometimes locks up.  The port to
the bandwidth shaper I know will always need to be in forwarding mode.  When
spanning tree detects that the traffic shaper is no longer passing traffic,
the other port will need to start forwarding in order to bypass it and reach
the routers beyond.


Regards,
>              Leigh
>
> Leigh Sharpe
> Network Systems Engineer
> Pacific Wireless
> Ph +61 3 9584 8966
> Mob 0408 009 502
> Helpdesk 1300 300 616
> email lsharpe at pacificwireless.com.au
> web www.pacificwireless.com.au
>
>
>  ------------------------------
>    *From:* richardvoigt at gmail.com [mailto:richardvoigt at gmail.com]
> *Sent:* Friday, July 06, 2007 10:03 AM
> *To:* bridge at lists.linux-foundation.org
> *Subject:* [Bridge] jumpstart stp port to forwarding state
>
>  Sorry if this is a dupe, but the mailing list join email got delayed by
> 10 or 12 hours and so I think this message wasn't accepted:
>
> ----------------
>
> I've googled for this, but since there are so many pages talking about
> linux boxes connected to CIsco equipment, I can't find anything relevant.
>
> Does linux bridging support anything like cisco's portfast (port starts in
> forwarding state)?  Is there a way (sysfs, ioctl) to at least change a po=
rt
> to forwarding immediately?  Even bridges with stp disabled take some time
> bringing ports up after a topology change.  If the delay can't be
> eliminated, can I wait for it somehow in my startup scripts to avoid init=
ial
> connection failures?
>
> My preference would be to have something like:
>
> brctl portfast br0 bond0.10 on
>
> or
>
> brctl initialstate br0 bond0.10 forwarding
>
>
>
> Also, can stp disable all ports in the same bridge?  I would assume not, a
> minimum spanning tree needs at least one port forwarding (could that port
> somehow be a different interface on the same box, not a member of the
> bridge?).  If at least one port is always forwarding, could the minimum c=
ost
> port be set to forwarding by default when the bridge is brought up (ip li=
nk
> set br0 up) irrespective of any portfast-alike setting?
>
> I'm trying to minimize startup time on a firewall.
>
> Thanks for any information you can provide.
>
> Ben Voigt
>
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