> On 5 Apr, 2019, at 6:10 pm, 'Neal Cardwell' via BBR Development <bbr-dev@googlegroups.com> wrote:
>
> Right. I didn't mean setting the codel target to 242us. Where the slide says "Linux codel with ECN ce_threshold at 242us sojourn time" I literally mean a Linux machine with a codel qdisc configured as:
>
> codel ce_threshold 242us
I infer from this that BBR's new ECN support won't work properly with standard CE marking behaviour, only with the sort of signal that DCTCP requires. Is that accurate?
Yes, that's correct. Thus far BBR v2 is targeting only DCTCP/L4S-style ECN.
SCE allows providing that sort of high-fidelity congestion signal without losing interoperability with RFC-3168 compliant flows.
Noted, thanks.
neal