[CentOS] Redundant LAN routing possible?

Sun Jul 11 02:59:16 UTC 2010
Jerry Franz <jfranz at freerun.com>

On 7/10/2010 2:21 PM, Emmanuel Noobadmin wrote:
> I've been reading that it's possible to set up a system with multiple
> NIC to provide redundant internet connectivity such that it will
> switch to a secondary connection if the primary ISP fails.
> Is it possible in a similar way to setup redundant LAN routing? I read
> that it is possible to aggregate/bond multiple NIC to stackable
> switches that support link aggregation and redundancy. But if only
> simple switches are available, is something like this possible?
> e.g.
> System A
> eth0 ->  lan switch/router 1
> eth1 ->  lan switch/router 2
> System B
> eth0 ->  lan switch 1
> eth1 ->  lan switch 2
> Then somehow specify that, if lan switch 1 fails, the two systems will
> switch to using switch 2 so that in case of a switch failure, the
> network continues to remain operational.

Yes. You can do it. I've done it before. All you need is the right 
choice of bonding mode . You set up bond0 for eth0 and eth1 and it 'just 
works'. To make it more robust, cross-connect the two switches as well.

Benjamin Franz