[77877] in North American Network Operators' Group
Re: The Cidr Report
daemon@ATHENA.MIT.EDU (Christopher L. Morrow)
Sun Feb 13 02:34:02 2005
Date: Sun, 13 Feb 2005 07:31:16 +0000 (GMT)
From: "Christopher L. Morrow" <christopher.morrow@mci.com>
In-reply-to: <20050212193845.GA32152@shekinah.ip.tiscali.net>
To: Alexander Koch <koch@tiscali.net>
Cc: "Stephen J. Wilcox" <steve@telecomplete.co.uk>, nanog@merit.edu
Errors-To: owner-nanog-outgoing@merit.edu
On Sat, 12 Feb 2005, Alexander Koch wrote:
>
> On Sat, 12 February 2005 14:58:42 +0000, Stephen J. Wilcox wrote:
> > From: "Stephen J. Wilcox" <steve@telecomplete.co.uk>
> > [...] - would you agree that most of the poor deaggregating is not intentional
> > ie that they're announcing their '16 class Cs' or historically had 2 /21s and
>
> Think about someone putting in a Null0 route and re-
> exporting stuff unconditionally, now after he originates
> his /19 he is then adding a /24 here, and a /25 there.
> Lack of experience, when you suggest to them they should
> remove these announcements they are afraid to change it,
> not understanding the implications, etc.
>
> Not to mention ppl using cisco and prefix lists, it is
> way too easy with cisco to say '/19 le 24', and then they
> use outbound prefix lists to their transit supplier
> (different, but related as I see it). Some transit ISPs
> use that a lot, and encourage the table growth.
There are some business reasons to de-aggregate. Look at some outages
caused by 'routing problems' (someone leaked my /24's to their peers,
peers, peer and my traffic got blackholed, because the public net only
knows me as a /20)
There are multiple reasons for deaggregation aside from 'dumb operator',
some are even 'valid' if you look at them from the protection standpoint.
-Chris
