Re: [tcpm] initcwnd updates?

One interesting draft on this topic since RFC 6928 is  Mark Allman's draft
from 2015:

  Removing TCP's Initial Congestion Window
  https://datatracker.ietf.org/doc/html/draft-allman-tcpm-no-initwin-00

Another related draft that is in progress is about reusing congestion
control parameters from previous connections over the same path:

  Convergence of Congestion Control from Retained State
  https://datatracker.ietf.org/doc/draft-ietf-tsvwg-careful-resume/

neal

On Fri, Mar 15, 2024 at 11:31 AM Kampanakis, Panos <kpanos=
40amazon.com@dmarc.ietf.org> wrote:

> Hi all,
>
> Sorry if this has been asked recently, but looking in the list archive, I
> can’t seem to find any discussions about it.
>
> I was wondering if initcwnd updates have come up in TCPM recently.
>
> It has been 14 years since draft-hkchu-tcpm-initcwnd started and 11 since
> RFC6928 got ratified.
>
> Many CDNs use initicwnds=30 or more to increase performance.
>
> Also, new post-quantum signatures, if they ever got deployed, could lead
> to >15KB of authentication data (certificate chain and CertificateVerify
> signature) which means they would add an unnecessary RTT when initcwnd=10.
> This has been in shown in various publications *[1]*
> <https://www.ndss-symposium.org/ndss-paper/post-quantum-authentication-in-tls-1-3-a-performance-study/>,
> *[2]* <https://dl.acm.org/doi/10.1145/3386367.3431305>, *[3]*
> <https://blog.cloudflare.com/sizing-up-post-quantum-signatures/>
>
> So, I was wondering, should investigating the increase of the default TCP
> initcwnd be a topic for discussion over a decade after the last increase?
> Has technology evolved enough for a new default initcwnd=15 or 20?
>
> Rgs,
> Panos
>
> [1]
> *https://www.ndss-symposium.org/ndss-paper/post-quantum-authentication-in-tls-1-3-a-performance-study/*
> <https://www.ndss-symposium.org/ndss-paper/post-quantum-authentication-in-tls-1-3-a-performance-study/>
> [2] *https://dl.acm.org/doi/10.1145/3386367.3431305*
> <https://dl.acm.org/doi/10.1145/3386367.3431305>
> [3] *https://blog.cloudflare.com/sizing-up-post-quantum-signatures/*
> <https://blog.cloudflare.com/sizing-up-post-quantum-signatures/>
>
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