[Ecn-sane] IETF 110 quick summary

[Pete Heist <pete@heistp.net>]

Just responding to Dave's ask for a quick IETF 110 summary on ecn-sane,
after one day. We presented the data on ECN at MAPRG
(https://datatracker.ietf.org/doc/draft-heist-tsvwg-ecn-deployment-observations/
). It basically just showed that ECN is in use by endpoints (more as a
proportion across paths than a proportion of flows), that RFC3168 AQMs
do exist out there and are signaling, and that the ECN field can be
misused. There weren't any questions, maybe because we were the last to
present and were already short on time.

We also applied that to L4S by first explaining that risk is the
product of severity and prevalence, and tried to increase the awareness
about the flow domination problem when L4S flows meet non-L4S flows
(ECN or not) in a 3168 queue. Spreading this information seems to go
slowly, as we're still hearing "oh really?", which leads me to believe
1) that people are tuning this debate out, and 2) it just takes a long
time to comprehend, and to believe. It's still our stance that L4S
can't be deployed due to its signalling design, or if it is, the end
result is likely to be more bleaching and confusion with the DS field.

There was a question I'd already heard before about why fq_codel is
being deployed at an ISP, so I tried to cover that over in tsvwg.
Basically, fq_codel is not ideal for this purpose, lacking host and
subscriber fairness, but it's available and effective, so it's a good
start.

Wednesday's TSVWG session will be entirely devoted to L4S drafts.