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[CCWG] Re: ABE and CUBIC parameters beyond beta

Michael Welzl <michawe@ifi.uio.no> Thu, 20 August 2026 10:37 UTC

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From: Michael Welzl <michawe@ifi.uio.no>
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Date: Thu, 20 Aug 2026 12:37:26 +0200
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To: Yoshifumi Nishida <nsd.ietf@gmail.com>
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CC: Kazuho Oku <kazuhooku@gmail.com>, ccwg@ietf.org
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Subject: [CCWG] Re: ABE and CUBIC parameters beyond beta
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> On 20 Aug 2026, at 11:07, Yoshifumi Nishida <nsd.ietf@gmail.com> wrote:
> 
> 
> 
> On Wed, Aug 19, 2026 at 4:21 AM Michael Welzl <michawe@ifi.uio.no <mailto:michawe@ifi.uio.no>> wrote:
>> 
>> 
>>> On 18 Aug 2026, at 20:18, Yoshifumi Nishida <nsd.ietf@gmail.com <mailto:nsd.ietf@gmail.com>> wrote:
>>> 
>>> Hi Michael,
>>> 
>>> On Tue, Aug 18, 2026 at 5:46 AM Michael Welzl <michawe@ifi.uio.no <mailto:michawe@ifi.uio.no>> wrote:
>>>>>  
>>>>>> In any case, Yes. If we want to make Reno with decrease factor 0.8 (which is AIMD(1, 0.8)) and AIMD (alpha, 0.85) be the same, alpha will be 0.729.
>>>> 
>>>> Yoshi, Kazuho: I must admit I’m lost with the maths here. What did you do with which equations in RFC 9438 to arrive at this?
>>> 
>>> This actually came back from time to time during the discussions in the past. 
>>> That's one motivation for me to write https://datatracker.ietf.org/doc/draft-nishida-ccwg-standard-cc-analysis/  I put a simple explanation for this in Appendix of the doc.
>>> I am thinking it might be good to publish this part of the explanations (could be an independent stream?) as a tip for discussions.
>>> --
>>> Yoshi
>> 
>> Many thanks!  I get it now. Yes I agree that this would be useful to publish!   but why only this part - have you dropped the ball on the draft-nishida-ccwg-standard-cc-analysis draft, seeing that it hasn’t been updated since 2024?  That’s a shame, I think the whole draft is a useful document, in general.
>> 
>> (sorry, perhaps the group’s discussion went negative?  I missed it, or forgot)
> 
> Thank you so much! That encourages me. :) Yes, I showed it before. 
> My general impression at that time was people are more interested in non-loss based CC and less motivated to improve loss based CC.

I see….


> However, while I can agree with this trend, I still personally think IETF needs to work on loss based CC as it's still used. 

I agree.

Cheers,
Michael

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