lagg(4) and failover

Pete French petefrench at
Tue Aug 12 11:30:14 UTC 2008

> 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)

> 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.


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