Re: [tsvwg] Fwd: New Version Notification for draft-heist-tsvwg-ecn-deployment-observations-00.txt

[Pete Heist <[e-mail]>]

New revision posted and some comments below...

On Sat, 2021-02-20 at 09:36 +0000, Bob Briscoe wrote:
> Pete,
> 
> If you plan to post a revision, in the TCP table (Sec.5.3) would you
> pls 
> consider including the counts of ECT packets, as in the non-TCP table
> in 
> Sec.5.3? Otherwise we don't know what percentage of the total ECN 
> traffic each count represent.

That's a useful addition. An ECT(0) column is now added, and the TCP
table's column order is now similar to the non-TCP table. ECE for the
opposite direction is still next to CE as that seems most readable. I
left out ECT(1) for TCP as there's so little of that, and then it gets
harder with the line length limit.

> I'm trying to separate out the IPs known to be behind the FQ-CoDel
> nodes 
> in the backhaul. I.e. separating known from unknown causes.

That's mentioned in Section 3.2.

> Separately, a count of total packets, or equivalently a count of 
> not-ECT, would be v useful too.

I didn't capture Not-ECT by IP address, mainly because some testing
made me question how at least one ipset lookup per-packet would affect
performance on their production gateway. I added that to the
Limitations section as it could be useful if available.

Pete

> If you can do this without losing the ECE counts, even better. Having
> CE 
> and ECE together enables a rough estimate of the average window.{Note
> 1}
> 
> Specifically,
>      avgWindow = ECE * delAckRatio / CE
> 
> Thank you (again)
> 
> 
> Bob
> 
> {Note 1} And lots of other assumptions, such as:
> - delayed Ack Ratio including stretch ACKs has to be guessed (e.g.
> 2???)
> - minimal additional ack coalescing in the network
> - minimal reordering
> - traffic volume dominated by elephants
> - the TCP protocol is working as it should
> - and so on.
> 
> 
> On 19/02/2021 13:06, Pete Heist wrote:
> > Yes, that was somewhat unexpected to us at first too, but misuse of
> > the
> > ECN field esp. on non-TCP packets seems to explain it in cases
> > where
> > there ratios don't look like AQM signaling. The data for TCP is
> > overall
> > easier to attribute to ECN when you can see feedback via ECE.
> > 
> > I didn't editorialize much on the results, but I'll use this as a
> > chance to add what struck me:
> > 
> > * While ECN negotiations were relatively small at around 1.44%,
> > they
> > were spread across 45% of the IPs, so the proportion of paths using
> > it
> > seems significant.
> > 
> > * The data seem to show significant 3168 marking AQM deployment,
> > when
> > 24% of LAN IPs that negotiated ECN saw CE or ECE. The draft
> > mentions
> > how some of it is from known AQM instances and some not. Congestion
> > overall doesn't seem excessive, but that could be quantified
> > better.
> > 
> > * A wider survey might help on the non-TCP data.
> > 
> > Anyway thanks for taking a look...
> > 
> > Pete
> > 
> > On Fri, 2021-02-19 at 11:44 +0000, Mirja Kuehlewind wrote:
> > > Hi Pete,
> > > 
> > > thanks for putting this together and sharing!
> > > 
> > > I have one question on the data. Maybe I'm not readying this
> > > correctly but if I look at the big table at the end, then I see a
> > > lot
> > > of cases where there are much more CE marks than ECT(0) marks.
> > > That's
> > > a bit unexpected as usually an AQM should only mark a small
> > > portion
> > > of the packets. Or do I interpret the data there incorrectly?
> > > 
> > > Mirja
> > > 
> > > 
> > > 
> > > On 18.02.21, 17:38, "tsvwg on behalf of Pete Heist"
> > > <[e-mail] on behalf of [e-mail]> wrote:
> > > 
> > > 
> > >      > A new version of I-D, draft-heist-tsvwg-ecn-deployment-
> > > observations-00.txt
> > >      > has been successfully submitted by Peter G. Heist and
> > > posted to
> > > the
> > >      > IETF repository.
> > >      >
> > >      > Name:             draft-heist-tsvwg-ecn-deployment-
> > > observations
> > >      > Revision: 00
> > >      > Title:            Explicit Congestion Notification (ECN)
> > > Deployment Observations
> > >      > Document date:    2021-02-18
> > >      > Group:            Individual Submission
> > >      > Pages:            27
> > >      > URL:
> > >    
> > > https://www.ietf.org/archive/id/draft-heist-tsvwg-ecn-deployment-observations-00.txt
> > >      > Status:
> > >    
> > > https://datatracker.ietf.org/doc/draft-heist-tsvwg-ecn-deployment-observations/
> > >      > Html:
> > >    
> > > https://www.ietf.org/archive/id/draft-heist-tsvwg-ecn-deployment-observations-00.html
> > >      > Htmlized:
> > >    
> > > https://tools.ietf.org/html/draft-heist-tsvwg-ecn-deployment-observations-00
> > >      >
> > >      > Abstract:
> > >      >   This note presents data gathered at an Internet Service
> > > Provider's
> > >      >   gateway on the observed deployment and usage of ECN.
> > > Relevant IP
> > >      >   counter and flow tracking data was collected and
> > > analyzed for
> > > TCP and
> > >      >   other protocols.
> > > 
> > >      This draft adds some data on the current usage of ECN. It
> > > was
> > > gathered over several weeks at a cooperative ISP with around 660
> > > members, and looks at ECN endpoint activity, AQM deployment and
> > > ECN
> > > usage on non-TCP protocols. While this study is still relatively
> > > small, it’s hopefully at least a little more useful than the
> > > stateless counter data I posted late last year, which should set
> > > the
> > > bar suitably low… :)
> > > 
> > >      Pete
> > > 
> > > 
> > 
>