[c-nsp] loss of advertised bgp route

Seth Mattinen sethm at rollernet.us
Tue Jul 10 16:08:21 EDT 2007


bill buhlman wrote:
> Hi All,
>   We've installed a new 7609 recently (up 3 weeks) and run BGP to connect to our upstream provider. We are announcing two prefixes, a /16 and /24. Since the install I've noticed connectivity to the ISP has gone down for a few minutes about 10 times, never during business hours. A couple of days ago this happened during business hours and we found out that our /16 was being dampend by the ISP due to our router not consistently advertising the prefix. 
>    
>   In BGP config we have both routes in with network statements and a neighbor prefix-list out with both prefixes. Also in ip routes we have "ip route x.x.0.0 255.255.0.0 Null0" which should keep the prefix advertised at all times as well. I'am running IOS 12.2(33)SRA3 and Cisco cant find any issues at the moment...can anyone shed some light on this? 
>    

If you're losing connectivity, there's your problem. You can try adding 
"no bgp fast-external-fallover" so it won't reset so quickly, but you 
should really troubleshoot your connectivity problems.

~Seth


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