/24s run amuck again

Richard A. Steenbergen ras at e-gerbil.net
Sat Jun 9 21:34:16 UTC 2001


On Sat, 9 Jun 2001, Randy Bush wrote:

> >>> There are lots of reasons to have some diverse /22 announcements in your
> >>> network for example.
> >> but if you are not paying me, what reasons are there for me to spend
> >> my resources (route bloat) so you can engineer your traffic?
> > The fact that your other customers are paying you to reach everyone on the
> > internet?
> 
> red herring alert!  the point is not reachability.  the aggregate is
> still available.  see bellovin's phoenix presentation.

Assuming there is an aggregate. Unless you know for certain that there is
one, you run the risk of making some addresses unreachable.

As an extension of something I mentioned in a previous message, perhaps
someone will be so kind as to play devils advocate and tell me why this
wouldn't work. Automatically aggregate more specifics with attributes
matching a shorter prefix at your network borders, and only pass the
aggregates to the rest of your network via IBGP. The EBGP speaking router
which receives the more specifics would keep a low memory record of them,
and in the event that the aggregate route was withdrawn the more specifics
would be advertised to the IBGP peers. In the event that an aggregate
route is announced, any already announced more specifics would be
withdrawn.

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
PGP Key ID: 0x138EA177  (67 29 D7 BC E8 18 3E DA  B2 46 B3 D8 14 36 FE B6)




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