Re: [tsvwg] L4S DSCP (was: L4S drafts: Next Steps)

[Steven Blake <[e-mail]>]

On Mon, 2021-03-22 at 19:30 +0000, Black, David wrote:
> Following up on Pete's comment:
> 
> > Along these lines, there is nothing stopping anyone from using DSCP
> > (as
> > an appropriate risk control within participating ASs), to perform
> > experiments to reproduce issues that can be demonstrated in the
> > lab.
> 
> That is a commendable approach, particularly as it is effectively
> recommended by RFC 4774 (Specifying Alternate Semantics for the
> Explicit Congestion Notification (ECN) Field) - see Section 3 [1],
> and take note that RFC 4774 is a BCP (Best Current Practice) whose
> author was the late Sally Floyd.  It may be time for the WG to
> reconsider the L4S approach of using alternate ECN semantics without
> qualification by DSCP, at least to run experiments on actual
> networks.
> 
> My 0.02 is that an Experimental RFC that used a DSCP to signal the
> L4S ECN semantics (in participating networks) could have been
> published at least 2 years ago.

I agree wholeheartedly (as I have said multiple times in the past).

As it stands, the -l4ops draft puts a burden on operators who are
minding their own business to evaluate and potentially make operational
changes to their network to avoid potential disruptions to their
network performance, for the benefit of someone else's experiment. That
is not appropriate IMHO nor is it necessary when an alternative (DSCP
isolation) is available.


Regards,

// Steve