400G forwarding - how does it work?

Matthew Huff mhuff at ox.com
Mon Aug 8 12:46:23 UTC 2022

Also, for data center traffic, especially real-time market data and other UDP multicast traffic, micro-bursting is one of the biggest issues especially as you scale out your backbone. We have two 100GB switches, and have to distribute the traffic over a LACL link with 4 different 100GB ports on different ASIC even though the traffic < 1% just to account for micro-bursts.

-----Original Message-----
From: NANOG <nanog-bounces+mhuff=ox.com at nanog.org> On Behalf Of sronan at ronan-online.com
Sent: Monday, August 8, 2022 8:39 AM
To: Masataka Ohta <mohta at necom830.hpcl.titech.ac.jp>
Cc: nanog at nanog.org
Subject: Re: 400G forwarding - how does it work?

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.


> On Aug 8, 2022, at 7:34 AM, Masataka Ohta <mohta at 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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