Objections to TCP BBR by default in 24.04?

[Daniel J Blueman]

On Sat, 27 Jan 2024 at 23:47, Andrea Righi <andrea.righi at canonical.com> wrote:
>
> On Sat, Jan 20, 2024 at 06:39:20PM +0800, Daniel J Blueman wrote:
> > Ubuntu has a distro-leadership opportunity to improve the end-user
> > experience for much of the world on higher-latency connections. With
> > TCP BBRv2 being materially unchanged for some time, it is widely
> > considered mature.
> >
> > If there isn't good rationale against this, I propose we enable TCP
> > BBRv2 by default for the 24.04 development phase, moving back to Cubic
> > if any issues are identified.
> >
> > Comments/objections?
>
> Hi Daniel, sorry for the late response, I had to investigate a bit about
> BBRv2 (I was not very familiar with it).
>
> Overall, it definitely looks interesting, but as far as I can see it has
> not been merged upstream yet (I assume you are requesting to include
> BBRv2, not just enable BBR by default, right?).

Indeed, after deeper investigation, fairness (eg vs CUBIC) fixes
haven't been backported to mainline BBRv1.

There is an on-going effort by Neal Cardwell et al to mainline BBRv3
which will be of greater benefit and stands to address the fairness
issues, therefore we should revisit the decision in later release
cycles.

Thanks!
  Dan
-- 
Daniel J Blueman