nanog mailing list archives

Re: 400G forwarding - how does it work?


From: Ca By <cb.list6 () gmail com>
Date: Mon, 8 Aug 2022 06:02:36 -0700

On Mon, Aug 8, 2022 at 5:39 AM <sronan () ronan-online com> wrote:

You keep using the term “imaginary” when presented with evidence that does
not match your view of things.

There are many REAL scenarios where single flow high throughout TCP is a
real requirements as well as high throughput extremely small packet size.
In the case of the later, the market is extremely large, but it’s not
Internet traffic.


I believe this all started with asic experts saying trade-offs need to be
made to operate at crazy speeds in a single package.

Ohta-san is simply saying your usecase did not make the cut, which is
clear.  That said, asic makers have gotten things wrong (for me), and some
things they can adjust in code, others not so much. The LPM / LEM lookup
table distribution is certainly one that has burned me in ipv6 and mpls
label scale, but thankfully SiliconOne can make some adjustments… but
watch-out if your network is anything other than /48s

The only thing that will change that is $$$.



Shane

On Aug 8, 2022, at 7:34 AM, Masataka Ohta <
mohta () necom830 hpcl titech ac jp> wrote:

Saku Ytti wrote:

which is, unlike Yttinet, the reality.
Yttinet has pesky customers who care about single TCP performance over
long fat links, and observe poor performance with shallow buffers at
the provider end.

With such an imaginary assumption, according to the end to end
principle, the customers (the ends) should use paced TCP instead
of paying unnecessarily bloated amount of money to intelligent
intermediate entities of ISPs using expensive routers with
bloated buffers.

Yttinet is cost sensitive and does not want to do
work, unless sufficiently motivated by paying customers.

I understand that if customers follow the end to end principle,
revenue of "intelligent" ISPs will be reduced.

                       Masataka Ohta





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