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0 pointsdtaht2y ago0 comments

I have tried to point out MANY times that the DEFAULT behavior of the TCP slow start algorithm is to saturate the link - however briefly - get a drop, and then back off. I try to do it with some humor using jugglers here - and get so far as slow start, I think, about 10 minutes in: https://www.youtube.com/watch?v=TWViGcBlnm0&t=510s

ALL NETWORKS have perceptible jitter due to this, unless you rigorously apply FQ and AQM techniques to each slower hop on the path

Fatter tests like waveform show the common bufferbloat scenario in ways humans can see, better. But slow start overshoot is always there, on any connection that lasts long enough, which only takes a couple RTTs. You can clearly see netflix doing you in here, for example...

https://www.youtube.com/@trendaltoews7143

(except that in this case, the link has libreqos and FQ on it, so all that buffering is just local to the netflix flow, invisible to everything else)

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acje2y ago· 1 in thread

Nice videos Dave. I guess I have personally given up on effective buffer management. Perhaps if ipv6 and infiniband becomes the underlying infrastructure? There is just so many layers of abstraction hiding no longer useful decisions in the stack that I have just decided to leave infra and networking behind for a while to see if one can make a difference elsewhere.

dtahtOP2y ago

Don´t give up. Ask for RFC7567 everywhere.

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