Re: OT - BGP Problem

You may want to look into using PfR as it has features that can deal with
your exact problem. In particular with PfR you are looking to monitor
passive reachability* which is done in PfR by looking for repeated SYNs
without a SYN/ACK for TCP sessions. Of course this will only work if TCP
traffic is flowing through the border routers which shouldn't be a problem.

The reason this solution is better than manually configuring IP SLA is
that it will reroute traffic even when Carrier A just has a partial outage
by rerouting the traffic Carrier A can't reach to Carrier B and not just a
full outage with Carrier A. Manually configuring IP SLA needs a
predefined destination where PfR using passive reachability will detect
the destinations automatically that are unreachable. You can even mix
passive reachability with active reachability (predefined destinations
using IP SLA) if you like.

* There is a short and long term passive reachability stat that is
collected if you want to reroute when the 5 minute average (short term)
breaks above a predefined percentage of the 60 minute average (long term).
 

-- 
Brian Dennis, CCIEx5 #2210 (R&S/ISP-Dial/Security/SP/Voice)
bdennis_at_ine.com
INE, Inc.
http://www.INE.com 
On 6/27/13 9:05 AM, "gaston brait" <gbrait_at_hotmail.com> wrote:
>I work for a company with 2 datacenter connected via a dark fiber and they
>have an IBGP peership between them.Both datacenter have EBGP peers to 2
>different carriers. Carrier A is the preferred one.The problem is that we
>have
>had several incidents where carrier A has problems on their cloud, but
>the BGP
>peer with us never goes down and we continue to recieve prefix from
>them.When
>this happens we lose all internet connectivity and we need to manually
>switch
>to carrier B.Is there any way to automate this process? Maybe track an
>internet route and if it is unreachable bring the peer down?
>Thanks,
>Regards,
>Gaston
>
>
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