Re: Link-state EGP

[Saku Ytti via NANOG <nanog () lists nanog org>]

On Sun, 24 Aug 2025 at 05:52, Jeffrey Haas <jhaas () pfrc org> wrote:

> The easy way to picture some of the impacts of that is consider what
> it'd take to distribute "at the boundary of AS X->Y, don't distribute
> prefix P".

If we imagine that we would have day1 had concern of people abusing
BGP and that we need to distribute >1M prefixes. We likely would have
considered we need out-of-band for validation reasons alone. So we
would have evolved a very different looking system.

And what limitations that system would have and how to work with them
would now look like requirements to us, when they were just the best
solution we could come up, with the tools we had in front of us.

I suspect all these disjoint advertisement problems that are
legitimate would be addressed by registering more ASN and moving the
ASNs between sites as needed. We do try to avoid disjoint today
already, and many companies have a peering policy which forbids it or
recommends against it. But it absolutely still happens, and in my
experience it happens more today, because CDNs use disjoint
advertisements to enforce their policies when customers override their
policies with local-prefs.

I'm very confident this system would just work, and Internet end users
wouldn't be none the wiser. But I have no confidence that it would be
worthwhile.

-- 
  ++ytti
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