Re: The trouble with route announcement updates.

[Christian Nielsen <]

On Tue, 10 Oct 2000, Jacques Caron wrote:

> - for "smaller" peers (up to a few hundred routes), build strict 
> prefix-lists based on IRR registrations. Update nightly.
> - for "larger" peers, build as-path filter-list (in the form "permit _AS$") 
> based on IRR registrations. Update nightly.

But does everyone update the IRR? I dont think so. I know many companies
that dont reg all their routes. 

> At 13:55 10/10/00, Neil J. McRae wrote:
> 
> >We, at COLT, ourselves use max-prefixes to handle inbound announcements
> >to our network - we did this because coping with the number of
> >updates, lack of any notification or process for notification
> >turned this into a full time job. We have atleast 2 or 3 new
> >routes every day.

Exodus also does this. We do filter routes for things we know should not
be announced to us. Some of them might include EP blocks, RFC1918, etc. We
also filter some of the larger blocks from peers. IE, we know that other
providers should not be sending us _701_|_1239_|_3561_|_1_|_etc. But if
you look, providers are usually leaking one or two routes from these
larger providers. It is usually a customer of a peer.

One thing we do is filter all customers. Customers are prefix-list
filtered. This makes sure that no customer can advertise any route to us
that we dont know about. 

So, for peers, we deny larger ASes from the peer and max-prefix the
peer. For customers, we prifix-list filter so they dont leak anything to
us we dont know about.

Christian.
----
Network Architect
BENGI - Exodus
AS3967 - NA  AS8709 - EU  AS4197 - AP	EXDS