North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: weird BGP cisco-ism?
In cisco.external.nanog you write: >I have a Cisco 7505 which is advertising about 50 routes to about 40 >peers at mae-west, and a few others. One set of customers has been complaining >that their connectivity is going away right at that router, and then coming >back. Narrowed the set of customers down to a single CIDR block, at >204.147.224.0/20. >So, some of our peers are claiming that the route is flapping... that's >weird, we have them all nailed up to static routes... especially the CIDR >blocks. So I wrote a tool which you can peer a router with, and it watches >the BGP traffic and prints anything it gets, formatted, to standard out. >My Cisco is sending fresh advertisements every 10-30 minutes for that route, >and not for any other of the routes it has, and it appeared to be all the same, >but on careful examination, it appears that each advertisement reflects a >change in the MULTI_EXIT_DISC from 0x00000000 to 0x00000014 and then back >again in the next advertisement. 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 >What the heck am I seeing here? Is someone's flap damping code seeing the >repeated advertisements and suppressing me? Is my Cisco going crazy? >-matthew kaufman > [email protected]
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