400G forwarding - how does it work?

Mon Aug 8 09:59:47 UTC 2022

Saku Ytti wrote:

>> When many TCPs are running, burst is averaged and traffic
>> is poisson.
> 
> If you grow a window, and the sender sends the delta at 100G, and
> receiver is 10G, eventually you'll hit that 10G port at 100G rate.

Wrong. If it's local communicaiton where RTT is small, the
window is not so large smaller than unbloated router buffer.
If RTT is large, your 100G runs over several 100/400G
backbone links with many other traffic, which makes the
burst much slower than 10G.

					Masataka Ohta