Re: [tcpPrague] [tsvwg] L4S and BBR (was: [iccrg] ecn-l4s-id: Proposed Changed to Normative Classic ECN detection Text)

Sebastian Moeller <> Sun, 01 November 2020 20:54 UTC

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From: Sebastian Moeller <>
To: Christian Huitema <>
Cc: Bob Briscoe <>, tsvwg IETF list <>, iccrg IRTF list <>, TCP Prague List <>, "De Schepper, Koen (Koen)" <>
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Subject: Re: [tcpPrague] [tsvwg] L4S and BBR (was: [iccrg] ecn-l4s-id: Proposed Changed to Normative Classic ECN detection Text)
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Dear Christian,

more below in-line, prefixed with [SM]

> Gesendet: Sonntag, 01. November 2020 um 21:02 Uhr
> Von: "Christian Huitema" <>
> An: "Bob Briscoe" <>, "tsvwg IETF list" <>
> Cc: "iccrg IRTF list" <>, "TCP Prague List" <>, "De Schepper, Koen (Koen)" <>
> Betreff: Re: [tsvwg] [tcpPrague] L4S and BBR (was: [iccrg] ecn-l4s-id: Proposed Changed to Normative Classic ECN detection Text)
> On 11/1/2020 5:30 AM, Bob Briscoe wrote:
> >
> > Quentin De Coninck wrote an initial implementation of a "QUIC Prague"
> > congestion control based on your picoQUIC code. It can be accessed via
> > the L4S landing page here:
> >
> > He started it at an IETF hackathon. I don't think it's been maintained
> > since it was first written, but it might be a start.
> Care doing a PR so this could be added to the Picoquic distribution?

       [SM] A cursory look at prague.c at the repository indicates, that this code might not fulfil the "eliminate RTT bias requirement" yet (I might have missed the implementation, hence "might not fulfil"). Odd since the repository is linked from the L4S site at rite, obviously just an oversight that will be fixed in due time?
Or a sign, that requiring individual protocols to fix up deficiencies in core AQMs is simply an unsustainable approach, if even a team L4S endorsed implementation is allowed to fall out of requirements.

Best Regards

> -- Christian Huitema