[101027] in North American Network Operators' Group

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Re: IPv4 BGP Table Reduction Analysis - Prefixes Filter by RIRs Minimum Allocations Boundaries

daemon@ATHENA.MIT.EDU (Andy Davidson)
Mon Dec 3 13:01:38 2007

In-Reply-To: <20221.1196626754@turing-police.cc.vt.edu>
Cc: Eduardo Ascenco Reis <eduardo@intron.com.br>, nanog@merit.edu
From: Andy Davidson <andy@nosignal.org>
Date: Mon, 3 Dec 2007 18:00:10 +0000
To: Valdis.Kletnieks@vt.edu
Errors-To: owner-nanog@merit.edu



On 2 Dec 2007, at 20:19, Valdis.Kletnieks@vt.edu wrote:

> On Sun, 02 Dec 2007 09:59:19 EST, Andy Davidson said:
>> On 29 Nov 2007, at 22:05, Eduardo Ascenco Reis wrote:
>>> The methodology shows a good efficiency (around 40%) reducing BGP
>>> table size, but the estimated number of affect prefixes are also
>>> high (around 30%).
>> This is an interesting piece of work, and highlights an interesting
>> model (40% table size saving hurts 30% of traffic.)
> No, it hits 30% of the *routes*.

Yes, I completely agree, bad terminology indeed.

> I'll make a truly wild guess and say that those 30% of routes  
> actually only represent 0.3% of the *traffic* for most providers,  
> and the *only* people who really care are the AS that's doing the  
> deaggregate...

As you nearly point out, it's 100% of the traffic for some networks,  
and will still be high for other networks.  The only way to feel  
confident that traffic is unaffected by routing table compression is  
to aggregate sensitively.  This is where my "permit one deagg"  
question came from.

Andy

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