[63586] in North American Network Operators' Group
Re: kooky BGP tricks
daemon@ATHENA.MIT.EDU (E.B. Dreger)
Wed Oct 8 04:22:08 2003
Date: Wed, 8 Oct 2003 08:21:30 +0000 (GMT)
From: "E.B. Dreger" <eddy+public+spam@noc.everquick.net>
To: nanog@merit.edu
In-Reply-To: <BBA98A01.399%dgolding@burtongroup.com>
Errors-To: owner-nanog-outgoing@merit.edu
DG> Date: Wed, 08 Oct 2003 09:31:45 +0200
DG> From: Daniel Golding
DG> 1) In a way, its fraudulent
If not mutually agreed in advance between 65000 and 65100, yes.
This is analogous to announcing more specifics from another
provider's space.
DG> 2) Some folks do BGP traffic engineering tricks using AS path. Other fo=
lks
DG> do measurement stuff using AS-Path. Therefore, wrong AS paths are bad.
True. Seeing "1239 $smallprovider 701" would be a bit bizarre,
pretending for a moment that 1239 accepted "$smallprovider 701".
DG> 3) Hacks are unscalable. This is a hack.
In a sense. In another sense, it's like 65000 sending 65100
partial routes... except it's actually a subset of 65000 doing
the talking.
I should have been more clear in my post. I originally was
addressing the issue of $smallprovider peering with a transit AS
when $smallprovider's upstream wouldn't. Ghetto multihoming was
a poorly-added afterthought, and probably muddled the question.
:-/
DG> Why doesn=B9t AS65100 just advertise the routes as "65100 65100 i" or "=
65100
DG> i"? What is gained by doing "65100 65000 I" other than ensuring that if=
the
DG> link between $downstream and AS65000 goes down, then $downstream become=
s
DG> unreachable from AS65000 due to BGP loop detection?
I've always seen inconsistent origin ASNs as "evil". They work,
but are generally frowned upon... perhaps it is the lesser of
evils, though.
DG> If I were AS65000, I might be disposed to complain to AS65100's upstrea=
m or
DG> to the large community about 65100 stealing my AS. I would suspect some=
evil
Again, I meant to indicate 65000 and 65100 agreed in advance.
DG> intent. Also, if $downstream cant afford $500 for an AS, what makes any=
one
DG> think they can afford to pay either upstream?
Very true.
And ASNs are still plentiful; running out is far enough down the
road not to worry...
Eddy
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