Re: [tcpm] Proceeding CUBIC draft - thoughts and late follow-up

[Yoshifumi Nishida <[e-mail]>]

Hi Markku,

Thanks for the comments. I think we're mostly on the same page for RFC9002.
I put some comments on the issue 1 part.

On Mon, Jul 11, 2022 at 7:54 PM Markku Kojo <[e-mail]> wrote:

>
> > BTW, my intention is not saying RFC9002 is overly aggressive. I just
> meant comparing with reno precisely might
> > not be a very good idea for modern networks.
>
> Agreed, it is not overly aggressive.
>
> I am not saying that CUBIC should be precisely as aggressive as Reno even
> though its design goal has been to be equally aggressive in the
> Reno-friendly region.
>
> Instead, with the issue 1, for example, a CUBIC flow competing with a
> Reno flow will incorrectly and against its design goal opt out
> roughly every second cwnd decrease that the Reno flow executes. Doesn't
> that result in systematic and significant difference in peformance like
> the measuement results that I've pointed to also confirm?
>
> I think we'll need more analysis on this point.
Let's say a CUBIC connection has 50 packets cwnd and a Reno connection has
51 packets cwnd, the available buffer is only 100 packets.
In this case, I'm not very sure which connection of packets will be dropped
hence not sure about the consequences.
I still believe we cannot be sure until we see some deep analysis for this.
This may take time, but I think it's necessary to get the conclusion on
this point.
--
Yoshi