Automatic Dampening Based Only On Interface Errors?

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Aug 7th, 2009
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Scenario: Point-to-point WAN connection between two EIGRP routers. Wan link is taking excessive errors to the point where EIGRP neighbor flaps but link itself does not i.e. line protocol remains up.

Dampening does not help in this case as link itself doesn't flap. Connectivity, however, is intermittent because of EIGRP neighbor flaps. UDP traffic is hardest hit.

Question: Is there a way to take an interface out of action for a period of time (like dampening) based solely on that interface exceeding some predefined error threshold versus it actually flapping? Alternatively, is there a dampening-type feature in EIGRP (beyond the hold timer) that removes routes for a period of time for a neighbor that is flapping?

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Overall Rating: 5 (2 ratings)
John Blakley Sat, 08/08/2009 - 07:43
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Not that I'm aware of. Generally to help with flapping, you'd use summary routes. Of course, this would only keep the routes that are in the remote routing tables from dropping out of the table and wouldn't do anything for your neighbor relationships. Is this what you're looking for?



6aganguly Mon, 08/10/2009 - 12:31
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Thanks, John. As you said, summary routes don't help with the intermittent connectivity on the router with the serial interface taking the errors. Looking for a way to take that specific interface out of action until the circuit errors/EIGRP neighbor flaps have stabilized much like IP event dampening would do if the interface itself was flapping.

6aganguly Mon, 08/10/2009 - 14:38
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Thanks, Edison. At first glance, that does look very promising! Will investigate further. Appreciate the pointer...

Joe Clarke Tue, 08/11/2009 - 08:55
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If you have any questions, or require help designing your EEM policy, post your question to the Network Management forum. There is also a good repository for sample EEM policies at .

6aganguly Fri, 08/28/2009 - 06:46
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EEM did the trick! We created a policy that automatically makes an interface EIGRP passive (and sends an SNMP trap) when certain interface error counters exceed thresholds. Thanks again!


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