lagg(4) and failover

Marian Hettwer mh at
Tue Aug 12 11:43:31 UTC 2008

Hi Pete,

On Tue, 12 Aug 2008 12:30:12 +0100, Pete French
<petefrench at> wrote:
>> However, IMO lacp doesn't solve that problem. lacp is used for link
>> aggregation, not failover.
> It does both - if one of the links becomes unavailable then it will
> stop using it. We use this for failover and it works fine, the only
> caveat being that your LACP device at the far end needs to look like
> a single phsyical device (the nicer Cisco switches do this quite happily)
thanks for that info.

>> The manpage states "In the event of changes in physical
> connectivity...".
>> Again, does that mean, the link needs to be physically unavailable? If
> so,
>> it'll be the same behaviour as in failover mode and doesn't solve my
>> problem of a misconfigured switch...
> lagg is to handle failover at the physical layer for when one of your
> ether ports fails, or someone unplugs a cable. If I understand you
> correctly you are looking for something at the next layer up, to handle
> a problem where the ports work fine, but are not going to their expected
> destinations. lagg won't do this.
Thats unfortunate...
bonding in Linux is capable of doing this and solaris too.
Well then. At least everythings clear now. And in the end, clarifing things
was the reason for that mail thread :)


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