RE: The Cidr Report

> Stephen J. Wilcox writes on 11/14/2003 7:16 AM:
> > So anyway, was discussing the cidr report at the last
nanog.. I was pointing out
> > that deaggregation is discouraged by the naming and
shaming and then someone
> > else pointed out that this list has scarcely altered in months.
> >
> > So, what can we do as the operator community if this
report isnt having the
> > desired effect?
> Stop accepting /24 type routes?

Please no... That will drop me off the map..

Yeah maybe but what about where the RIRs have assigned
independent /24 space..
or ISPs have subdelegated the IPs to a multihomed customer,
was more thinking
about where a bunch of routes originating from a single ASN
can be aggregated
rather than routing bloat in general. There are numerous such
examples of people
with eg a /19 announcing 32x /24 etc


I don't have the stats handy at the moment, but we decided to Multi-home
I researched several issues with /24 blocks. One thing that seemed to stick
out was that some providers were using /20 and /21 as "multi-home" blocks.
They were reserving that block just for /24 multi-homing.. and I also remember
that of the /24 being annouced independently, a majority of them were not

just how bad is the auto-summarization at the upstream for the route propagation
via BGP in the large routers anyway?


What auto-summarisation?

If you're talking about the cisco "auto-summary" command, then the answer is "so bad that it's universally disabled" (but then "auto-summary" is concerned with aggregation on pre-CIDR, classful boundaries which I don't think is what you were talking about).

Absent a precise understanding of all the routing policies concerned, proxy aggregation is dangerous and is hence generally not done.