Re: Route table growth and hardware limits...talk to the filter

[Leo Bicknell <bicknell () ufp org>]

In a message written on Fri, Sep 07, 2007 at 07:14:01PM -0400, Jon Lewis wrote:
> For some reason, today I started out with fewer routes (228289...yesterday, 
> I started with 230686) with no filtering.
>
> RIR filter section    Reduction in routes
> APNIC                 16690
> ARIN                  41070
> RIPE                  16981
> LANIC                  4468
> AFRINIC                        1516
> -----------------------------
> TOTAL                 80725
>
> The end result of applying all the RIR minimum allocation filters was 
> 147564 BGP routes.  I haven't checked to make sure there was no loss in 
> reachability...this is just an idle 7206/NPE225 with nothing but its 
> ethernet uplink.

The CIDR report states that we have 235647 routes that could be
aggregated to 154503 routes.  While not the same metric, I'd be
surprised at 147,564 routes if you did not have reachability issues.

> The prefix-list I'm using for this experiment is:

One idea I've seen tossed around is to allow for a small amount of
deaggregation.  For instance, if in a /8, the RIR allocates down
to a /20, you might allow a /21 (break it into two blocks) or a /22
(break it into four blocks).  Yes, that allows people with bigger
allocations to break into more blocks, but it also allows everyone
to do some TE without letting them do an unlimited amount.

I fear some filtering is in our future.  I'm not really opposed to it,
either.  However I'm afraid your results show the currently available
filters to be too aggressive.


-- 
       Leo Bicknell - bicknell () ufp org - CCIE 3440
        PGP keys at http://www.ufp.org/~bicknell/
Read TMBG List - tmbg-list-request () tmbg org, www.tmbg.org

Attachment: _bin
Description: