Re: [tsvwg] L4S vs SCE

Ingemar Johansson S <> Wed, 20 November 2019 10:49 UTC

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From: Ingemar Johansson S <>
To: Kyle Rose <>, Ingemar Johansson S <>
CC: Sebastian Moeller <>, G Fairhurst <>, "" <>, "" <>, "De Schepper, Koen (Koen)" <>, "" <>, Ingemar Johansson S <>
Thread-Topic: [tsvwg] L4S vs SCE
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Date: Wed, 20 Nov 2019 10:49:30 +0000
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Subject: Re: [tsvwg] L4S vs SCE
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So given the imagined outcome that L4S fails.. two scenarios


If other SDOs or developers don’t pick up L4S then things are quite simple I guess, just declare the L4S drafts as deprecated, or is there more to do ?


But, if e.g. 3GPP somehow thinks that this is a good idea and adopts it.. Will the IETF send a message (LS?) to 3GPP with the message “please stop using L4S”, is this even a reasonable scenario?. After all, the fact that it is picked up by other SDOs, speaks against a failure ?




From: Kyle Rose <> 
Sent: den 20 november 2019 11:14
To: Ingemar Johansson S <>
Cc: Sebastian Moeller <>de>; G Fairhurst <>uk>;; Ingemar Johansson S <>om>;; De Schepper, Koen (Koen) <>om>;
Subject: Re: [tsvwg] L4S vs SCE


On Wed, Nov 20, 2019 at 6:04 PM Ingemar Johansson S < <> > wrote:

>       How do you expect an industry/commercial roll-out of L4S
> technology to behave, if the L4S experiment should terminated without
> adoption as a standard track RFC? Are they supposed to phase-out using
> ECT(1) as well, or is it understood that deployed L4S instances continue using
> L4S methods?

[IJ] The premise would be that L4S is declared a failure. I doubt that anybody has a good enough crystal ball to predict what happens. First it is necessary to come to the conclusion that L4S is a failure and I would argue that we are not yet there and I don't currently see that coming. Before that possible event I don't see it meaningful to speculate.


I'm going to have to go ahead and disagree with you strongly here. Given the potential consequences of cleaning up after a failed experiment without a plan worked out beforehand, this blithe approach is simply not acceptable.


In lots of cases, experiments are easy to terminate in an obvious way: for example, in one typical case, a code point can simply be abandoned, or (even better) a pollutable experimental code point returned to the available pool after some time. If that were the case here, it would not be difficult to enumerate a sequence of steps required to do so. It doesn't appear that's the case, however, so all the more reason to make sure we address this as part of the experiment setup.


A launch escape system of the necessary complexity should be a requirement of any experimental deployment. In this case, that might circumscribe the scope of the experiment itself.