it's efficient to set rules in order of increasing specificity, with the
more specific rules (by definition for a smaller address range) taking
priority. 

e.g. in this case you could say "route the 256-address-space to a black
hole" + "route the 64-address-subset to the real youtube", with the
latter rule taking precedence. doing the same thing without precedence
would require at least three rules, "route the X addresses before the
64-address-subset to a black hole", "route the X addresses after the
64-address-subset to a black hole", "route the 64-address-space to the
real youtube".

-rishab

On Tue, 2008-02-26 at 22:36 +0530, Suresh Ramasubramanian wrote:
> Lawnun wrote:
> 
> > Why does shrinking the number of addresses create 'priority' as far as
> > the  BGP is concerned?  Is there some merit to fewer addresses, as opposed
> > to more?
> 
> Something about specific routes being preferred. That's stuff you learn in
> cisco router classes. Oh, it didn't work - not for all the cases.



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