From: Darby Weaver (darbyweaver@yahoo.com)
Date: Sun Jun 04 2006 - 05:06:52 ART
Simple just change the AD of the links.
Preferred Link has a lower AD.
Non-preferred link has a higher metric.
When the Preferred link is available it will be used.
When it is down it will automatically (dynamically)
choose the non-preferred higher AD link.
Remember Floating Static Routes?
Also, I'd have to look deeper but IP SLA can be used
to report the status of a farside link and the results
can be used in a fashion to perform the feat you are
looking for.
Now if you have several links between the MAN, and you
are asking for a solution for something other than the
two immediate links, I'd be hard-pressed to recommend
a static solution, since taking something other than
point-to-point interfaces and trying to create a
preference when there may be an untold number of
variables involved would be tricky at best.
Do you have more details on the exact nature of the
infrastructure between your two sites and exactly what
lies in between?
I keep thinking to use IP SLA to track the far-side
link. And use Floating Static Routes in case a local
interface fails.
Anyone think of anythng better?
--- Donny mateo Tandase <donnymateo@yahoo.com> wrote:
> NOrmally it would be VRRP/HSRP with interface
> tracking, but since you said that it's Ethernet than
> this is not possible unless you have a method to
> track end to end link condition (something like
> frame-relay end to end keepalive.
> Perhaps a tunnel might do the job.. Not sure never
> tried this.. basically, create a point to point
> tunnel (GRE will do) with static route pointing to
> the other end specific IP address.
> After that you create another static route
> pointing to the tunnel interface for the routing
> between the two site (the first static route is only
> to get the tunnel up and running since there is no
> routing protocol). Never tried this, so you have to
> try it.
>
> THe best solution of course is the one that is
> currently not possible... which is routing
> protocol.. :)
>
> Cheers,
> Donny
>
> Bola Adegbonmire <bolaccie@yahoo.com> wrote:
> Hi All,
>
> I have got a client who has a branch office with two
> different physical links back to HQ. Both links are
> over a shared service provider metropolitan area
> network. Both links are delivered via Ethernet
> interfaces to the branch router (ISR 2811).
>
>
> The client does not use a dynamic routing protocol
> Static routes are in use
> Client requires a solution that will provide dynamic
> failover between the primary and secondary links
> when the primary is not available. The above caveats
> cannot be changed for now.
>
> Please can anyone help with a solution, considering
> the peculiarities of Ethernet interfaces not
> detecting the remote end been down as long as the
> local interface is seen as up/up when plugged into a
> switch port.
>
> Regards,
> Bola
>
>
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