[182602] in North American Network Operators' Group
Re: FIB Sizing
daemon@ATHENA.MIT.EDU (Pablo Lucena)
Sat Jul 25 16:20:12 2015
X-Original-To: nanog@nanog.org
In-Reply-To: <CAP-guGUivrrRijvqKG+pwtLA6gcNOJP9AvZo4FrM07ftzk897w@mail.gmail.com>
From: Pablo Lucena <plucena@coopergeneral.com>
Date: Sat, 25 Jul 2015 16:19:49 -0400
To: William Herrin <bill@herrin.us>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
>
>
> > When will router vendors learn to do even simple aggregation before
> loading
> > routes into FIB? It appears that most hardware will have plenty of FIB
> > space if this was done. Also that aggregated routes are increasing at a
> > slower pace.
>
> Howdy,
>
> You can get a good reduction with FIB aggregation, but only upwards of
> 50% or so, and that only with the some pretty costly algorithms. Also,
> you tend to get better gains at the cheaper edge nodes rather than the
> more expensive core nodes. For now it's more cost effective to leave
> the code alone and just double the size of the TCAM.
>
> Regards,
> Bill Herrin
>
>
=E2=80=8BThere are also features such as Selective RIB Download (or its equ=
ivalent
in other vendors) which help out in different portions of the network.=E2=
=80=8B
Definitely not applicable to all router types though.
