[c-nsp] BGP order of operation

[Gert Doering]

Hi,

On Sun, Apr 09, 2006 at 09:16:46PM +0300, Hank Nussbacher wrote:
> Can someone point me at a Cisco doc that describes what BGP neighbor
> statement takes preference or overrides another?
> 
> There is advertise-map, default-originate, distribute-list, filter-list to
> name a few. Who overrides whom?  Example: if I have default-originate to a
> neighbor but at the same time I have a distribute-list of "deny any", will
> the 0.0.0.0 that default-originate wants to announce be blocked by the
> distribute-list?  I can list many other examples but prefer not to lab
> each of them to determine which bgp neighbor command is "stronger".  I am
> just looking for a doc page that indicates the rules.

For output policies, as far as I understand (and have always used), all
policies need to "permit" to permit a given prefix out (like an "AND"
conjunction).

For input policies, I think it's the same - the moment a term drops 
a prefix (filter-list, distribute-list, route-map) it's gone, so no other
term has a chance to "re-vive" it.

No "overrides".

gert

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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de