Re: [tsvwg] Todays Meeting material for RTT-independence in TCP Prague

"Rodney W. Grimes" <> Sat, 29 February 2020 16:56 UTC

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From: "Rodney W. Grimes" <>
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To: Sebastian Moeller <>
Date: Sat, 29 Feb 2020 08:56:51 -0800 (PST)
CC: "De Schepper, Koen (Nokia - BE/Antwerp)" <>, tsvwg IETF list <>
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Subject: Re: [tsvwg] Todays Meeting material for RTT-independence in TCP Prague
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Koen, Sabastian,
	I have been following this thread and find a statement made that I have first hand information about that contridicts a statement made here and I wish to inject that into the thread.


> Dear Koen,
> thanks for the information. More below in-line...
> > On Feb 27, 2020, at 17:30, De Schepper, Koen (Nokia - BE/Antwerp) <> wrote:
> > 
> > Hi Sebastian,
> > 
... much good text removed ...

> > Similarly a lot of people don't even care at all about RTT unfairness.
> 	[SM] Yes, but quite a lot of people will start caring once you roll-out L4S; if it will noticeably affect their achievable goodput in the non-LL queue with competing LL-queue traffic. That is my point, the issue is the observed unequitable sharing behavior over short paths (think home network to data center, pretty much one of the main use-cases for L4S), not RTT-dependence per se. In a sense you just made my point for me.

In my un official but informative survey of "why ECN is not turned on at X" one of the answers I received was "because of the RTT unfairness it causes",
this was a very large content provider of the internet.  So though it might be true that "a lot of people" don't care about RTT unfairness it only takes a few large people to care and this becomse an issue.  I can state that at least one "large entity" cares.

So we (ietfers), IMHO, must not dismiss things based on this criteria that people do not care about RTT unfairness.

> Best Regards
> 	Sebastian
... much more good text removed ...

Rod Grimes