[CentOS] Redundant LAN routing possible?

Sun Jul 11 04:48:26 UTC 2010
Emmanuel Noobadmin <centos.admin at gmail.com>

Thanks for the suggestion, I'll read up more about them. The
bond0 and just works sounds simple which is a Good Thing!  The problem
was the last time I tried to cross connect multiple switches,
everything just died so there must be something a bit more involved?

In the mean time since my post, I came across STP (spanning tree
protocol) that seems to be designed to handle this sort of thing, i.e.
figure out the shortest path and prevent network shortcircuit like
what I had experienced with cross connecting multiple switches.

But it apparently takes 50 seconds to reconfigure anytime sometime in
the circuit fails. There is supposedly a Rapid STP that only takes 3
seconds. Several couple-of-years old search results indicate that it
was tested in 2.4 kernel and will be in 2.6 kernel. However, I cannot
seem to find anything newer that confirms if such functionality is
really in the current kernel. Anybody has any idea?

On 7/11/10, Jerry Franz <jfranz at freerun.com> wrote:
> 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
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