FIB Sizing

Sat Jul 25 20:19:49 UTC 2015

>
>
> > 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
>
>
There are also features such as Selective RIB Download (or its equivalent
in other vendors) which help out in different portions of the network.
Definitely not applicable to all router types though.