Re: [RRG] Opportunistic Topological Aggregation in the RIB->FIB Calculation?

["William Herrin" <bill@herrin.us>]

On Wed, Jul 23, 2008 at 7:46 AM,  <ksriram@nist.gov> wrote:
> Quoting William Herrin <bill@herrin.us>:
>
>> On Tue, Jul 22, 2008 at 5:35 PM, K. Sriram <ksriram@nist.gov> wrote:
>> > At 02:32 PM 7/22/2008, William Herrin wrote:
>>
>> > X can be quite large for core BGP routers -- 100s of peers or BGP
>> > interfaces.
>
> Please see slides 33-36 from this presentation:
> http://www.antd.nist.gov/~ksriram/BGP_Security_Analysis_NIST_Study.pdf


Very interesting. To summarize: about 10% of the ASes have at least 10
neighbors and a little over 1% have more than 100. One AS appears to
have had 3,622 neighbors!

Can we extrapolate from this to guess at the configuration of
individual routers? I would expect that even with MPLS in play, a
particular router would have a handful of external exits plus a bunch
of MPLS labels functioning as virtual exits, each leading to a router
that then has another handful of external exits.

I would imagine, for example, that the gentleman with 3,622 neighbors
doesn't have 3,622 unique best-next-hops in any one of his routers'
FIBs. So what -does- he have? And how many routers does he have that
on?

Regards,
Bill


-- 
William D. Herrin ................ herrin@dirtside.com bill@herrin.us
3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004

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