Re: Route-maps and clearing BGP table.

Unanswered Question
Jul 19th, 2009
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Hi,

I just want to check if I have a connection like this


R1 -- R2

and it is running eBGP between them. R1 has a route-map outbound to R2 that gives different MED values

for a bunch of routes. I shutdown the link on R1 going to R2. The bgp table would still show the routes to R2

until I do a 'clear ip bgp * soft' right ?

Pls advice,


Cheers,

InternetB.

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Giuseppe Larosa Sun, 07/19/2009 - 22:59
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Hello InternetB,


there are additional mechanisms like ebgp fast-external fallover that tears down the eBGP session as soon as the link to the eBGP peer is detected down.

Even without this when BGP holdtime expires the session is torned down and learned routes are removed.

You don't need to use clear ip bgp * to get this.

link failure Detection time is link dependent and it can take up to 3 keepalives (30 seconds).

ebgp fast external fall-over is enabled by default in modern IOS images.



Hope to help

Giuseppe

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