nanog mailing list archives

Re: weird BGP cisco-ism?


From: Ravi Chandra <rchandra () cisco com>
Date: Fri, 11 Jul 1997 00:58:51 -0700

add a default-metric under router bgp.. I think the source of the
route in the routing table is changing for some reason and the box is
conveying the metric as MED...

--ravi

Did that. It went from advertising it with an MED of 0 to an MED of 20 and
back, to just readvertising it over and over with the fixed default MED
I'd set (1).


This indicates that your flap is fixed.. the neighboring AS will look
at these advertisments as duplicate and discard it (and hence no
dampening). 

To avoid readvertising the same prefix, you might want to check if
there is any other dynamic protocol that is installing that prefix in
the routing table and removing it (could be a OSPF subnet...)



The sad thing is that until flap damping code was added, this sort of
bug was masked... but now I have a few dozen customers totally offline.



As soon as the reuse interval kicks in they should be fine..

--ravi


-matthew




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