nanog mailing list archives

Re: Route optimization using GPUs?


From: William Herrin <bill () herrin us>
Date: Fri, 6 Dec 2024 09:01:13 -0800

On Fri, Dec 6, 2024 at 8:34 AM Nick Hilliard <nick () foobar org> wrote:
BGP ensures loop-free interdomain path computation by inspecting the AS
path of each NLRI.  If a routing optimiser rewrites all the AS paths for
all the NLRIs it receives, then it's just pooped all over the primary
component of BGP that's designed to ensure that interdomain BGP actually
works in the way that it's supposed to do in the first place, which also
acts as an intrinsic safety guard against dfz hijacking.

As an industry, we should be well beyond the point of having to tell
people that this is a poor idea,

Hi Nick,

Have you ever filtered routes from the BGP table and replaced them
with a default route? Perhaps the TCAM was too full and you weren't
ready to upgrade yet?

There's nothing inherently wrong with filtering BGP routes and
replacing them in local routes of your own selection. Nor is there
anything wrong with using a complicated and detailed local selection
process. The error lies in allowing those local routes to accidentally
escape your AS.

Since people being people, they make mistakes, I thought a little
standards work in the area might head off some of those escapes.

Regards,
Bill Herrin

-- 
William Herrin
bill () herrin us
https://bill.herrin.us/


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