maximum ipv4 bgp prefix length of /24 ?

Sun Oct 1 08:00:29 UTC 2023

On Sun, 1 Oct 2023 at 06:07, Owen DeLong via NANOG <nanog at nanog.org> wrote:

> Not sure why you think FIB compression is a risk or will be a mess. It’s a pretty straightforward task.

Also people falsely assume that the parts they don't know about, are
risk free and simple.

While in reality there are tons of proprietary engineering choices to
make devices perform in expected environments, not arbitrary
environments. So already today you could in many cases construct
specific FIB, which exposes these compromises and makes devices not
perform. There are dragons everywhere, but we can remain largely
ignorant of them, as these engineering choices tend to be reasonable.
Sometimes they are abused by shops like EANTC and Miercom for
marketing reasons for ostensibly 'independent' tests.

I think this compression is part of this continuum, magic inside the
box I hope works because I can't begin to have a comprehensive
understanding exactly how much risk I am carrying.

Pretty much all performant boxes no longer have bandwidth to store all
packets in memory (partial buffering), many of them have 'hot' and
'cold' prefixes. You just gotta hope, you're not gonna be able to
prove anything, and by trying to do so, you're more likely to increase
your costs due to false positives than you are to find an actionable
problem. Most problems don't matter, figuring out which problem needs
to be fixed is hard.

-- 
  ++ytti