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From: David Schwartz on 25 Mar 2010 18:36
On Mar 25, 8:57 am, Bruce Richardson <itsbr...(a)uklinux.net> wrote:

> It's the simplest way to configure it, in the desired solution, but
> there can be problems.  Active-backup over two switches is fine *as long
> as you never see a cable failure*.  As soon as the active link fails,
> any device which was connected to the same switch is going to fail to
> connect to anything until the switch decides it no longer has a
> connection to the relevant mac address, because the switch will not try
> forwarding any ethernet frames to other switches until then.  This is
> something you should test.

The switch the dead link is connected to will decide it has no
connection to the relevant MAC address instantly -- the port it had a
connection to just went down. The switch the newly-live link is
connected to should update its table as soon as it sees the first
packet that originates from that link.

DS
From: Rick Jones on 25 Mar 2010 20:26
Bruce Richardson <itsbruce(a)uklinux.net> wrote:
> Rick Jones <rick.jones2(a)hp.com> wrote:
> >
> > The switches need to be in the same broadcast domain right? If there
> > is a gratuitous ARP on the failover, won't that propagate around and
> > cause the switch in question to relearn where that destination MAC
> > resides (assuming the failover preserves the MAC rather than causes a
> > new IP-MAC translation)

> OP didn't say anything about gratuitous ARP, which isn't something that
> automatically comes with bonding.

Sorry about that - I was projecting what I'm told HP-UX APA (Auto Port
Aggregation) does in LAN Monitor mode (what it calls active-standby)
onto Linux bonding.

rick jones
--
denial, anger, bargaining, depression, acceptance, rebirth...
where do you want to be today?
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
From: Andreas Moroder on 26 Mar 2010 04:10
> The problem with bridging is that failover time is in the order of 30
> seconds or so since linux bridging does not support anything else than plain
> old STP (ie, no RSTP etc.). Of course the STP parameters can be tuned, but
> you must know what you're doing, and you still can't get less than a few
> seconds failover time.
>
Hello,

according to

http://kerneltrap.org/mailarchive/linux-netdev/2008/7/9/2403834

RSTP should already be available for linux as userspace daemon.

Someone has tested this ?

Bye
Andreas
From: David Schwartz on 26 Mar 2010 05:17
On Mar 25, 10:13 am, Rick Jones <rick.jon...(a)hp.com> wrote:

> The switches need to be in the same broadcast domain right?  If there
> is a gratuitous ARP on the failover, won't that propagate around and
> cause the switch in question to relearn where that destination MAC
> resides (assuming the failover preserves the MAC rather than causes a
> new IP-MAC translation)

I don't think you need a gratuitous ARP. Most switches treat ARPs the
same way as they treat any other packet, so any outbound non-special
packet would do.

DS
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