North American Network Operators Group

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Re: The Cidr Report

  • From: Alexander Koch
  • Date: Sat Feb 12 14:39:54 2005

On Sat, 12 February 2005 14:58:42 +0000, Stephen J. Wilcox wrote:
> From: "Stephen J. Wilcox" <[email protected]>
> [...]   - 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.

Also I think a further problem is (from experience) some
content hosters wanting to bleed (right word?) /24's to
their providers, even though their ratio is 10:1 or more and
inbound traffic is not exactly relevant.  Too often it makes
no sense, and I am speaking of the '32* /24 is a /19'
version, mind you, sometimes not even announcing the

Seeing the larger DSL prefixes in Europe then in Europe
what do we conclude? See for 3352 or 3269 (sorry)... But
when we try to measure (de-) aggregation by continent it
gets tricky... (and I believe I know winner and loser)

I am not sure doing it the Swisscom way (they filter a lot)
is the way to go, yet I would be curious how many routes
they currently carry for a full route set. Ah, here it is:

->>sh ip bg su | incl 3303   4  3303 3351176  140593 74037481    0    0 2w2d        69713

I have a hard time argueing this topic with customers, and I
have the feeling I am not the only one. We are past that
already, I feel.

> so to repeat my earlier suggestion - if transit providers, particularly the 
> larger ones setup scripts to notify their customers daily/weeks of routing 
> deaggregation do you think we might gain some traction in educating and fixing 
> this?

That may be a way to go actually. Like the mail for what
prefixes are lacking a route: object that one might just send
to customers, not to peers... (5430 peers surely remember)