Route table growth and hardware to the filter

Sam Stickland sam_mailinglists at
Tue Sep 11 14:54:39 UTC 2007

Forrest wrote:
> Maybe this is a dumb question, but why isn't there a BGP option to just
> filter more specific routes that have the same AS path as the larger
> aggregate?  This would allow the networks that announce more specifics for
> traffic engineering to still accomplish that, while throwing away the
> garbage from someone else that decides to announce their /19 as 33 routes
> for no apparent reason.  Sure, this would fail if a network decided to 
> only announce /24's for example without a larger aggregate, but how many 
> networks are really doing that?
> Forrest
There's a couple of feature requests open at Cisco that would do this. 
Rodney Dunn (at Cisco) pushed quite hard for these but couldn't get any 
traction. As he's previously pointed out it would have if people would 
vote for them (attach a case to).


Rodney Dunn wrote:

Take your pick.  :) 

CSCsa45474 Ability to block overlapping BGP prefixes from being installed in RIB

or better:

CSCsa46049 IOS RIB should not install overlapping routes with same next hop


On Tue, Oct 03, 2006 at 05:26:51PM +0200, Gert Doering wrote:

> > Hi,
> > 
> > On Tue, Oct 03, 2006 at 11:09:16AM -0400, Rodney Dunn wrote:
>> > > I could never get them to agree to do it before and I have no reason
>> > > to believe anything has changed.
> > 
> > Is there a CSC number that one could attach cases to?
> > 
> > gert
> > -- 
> > USENET is *not* the non-clickable part of WWW!
> >                                                            //
> > Gert Doering - Munich, Germany                             gert at
> > fax: +49-89-35655025                        gert at
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