[c-nsp] Filtering BGP routes with route-map vs. not getting them in

[Michael K. Smith - Adhost]

For customer only routes wouldn't this be better to account for
prepending?

Ip as-path access-list 5 permit ^(providerAS_)+([0-9_])+$

Regards,

Mike

> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> bounces at puck.nether.net] On Behalf Of OCOSA ListAcct
> Sent: Friday, July 06, 2007 12:03 PM
> To: Kristian Kielhofner
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Filtering BGP routes with route-map vs. not
> getting them in
> 
> True if really want to use option b...
> 
> use this string to get routes directly connected to your upstream or
> originated.
> 
> ip as-path access-list 5 permit ^upstream as goes here_[0-9]*$
> 
> or
> 
> 
> to deny any networks originated form your upstream...and allows
> everything else which could be bad if your router does not have at
> least
> 512MB
> 
> ip as-path access-list 6 deny _upstream as goes here$
> ip as-path access-list 6 permit .*
> 
> 
> If I remember correctly you can also limited the amount of prefixes a
> neighbor can send you...
> 
> router bgp as number
> nei x.x.x.x maximum-prefixes and the rest....
> 
> I think the command is
> 
> 
> Otis
> 
> Kristian Kielhofner wrote:
> > Hello everyone,
> >
> >   I'm back with another stupid "BGP on a 3750" question.  I need
> > "customer only routes" to the few providers that I have.  From what
I
> > can tell, I'd end up with far less than the 8,000 max routes this
> > platform can handle.  I have two options when configuring this:
> >
> > a)  When bringing up the BGP session, I can request aggregated
> > customer-only routes (what I want).
> >
> > or...
> >
> > b)  I can request a full table and filter them myself with route-map
> > statements (I think).
> >
> >   With "a" I will have a much simpler configuration (not that it
> > matters much).  Will the 3750 have problems even receiving these
> > routes, even if I am filtering them?  I can imagine all sorts of
> > potential nastiness with that configuration.
> >
> >   If not, I'd much rather go with option "b".  I would have more
> > control over my routing and it would be easier to upgrade to a more
> > capable router in the future (less co-ordination with ISPs, just
> > remove route-map statements).  I like this idea more.  Can the 3750
> do
> > it?  What would happen?
> >
> > Thanks!
> >
> >
> 
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