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

[Gorry Fairhurst <[e-mail]>]

So injecting a little more history here.

Some previous discussions are:

The earliest discussion of L4S in the IETF that I recall was in 2015. 
When discussing, it was known that RFC4774 would allow experimentation 
with a diffserv domain (e.g., as in RFC 6660), but the practicalities of 
deploying an end-to-end Internet transport required an RFC to use a 
method that was not protected by a DSCP. The discussion on whether the 
ECN Plus a Diffserv Codepoint (DSCP) was also noted in the appendix of 
draft-briscoe-tsvwg-ecn-l4s-id-00 in 2015.  R

Tradeoffs that lead to using ECT(1) were described in the proposal to 
the AQM working group in draft-briscoe-aqm-dualq-coupled-00 in 2015.

The interaction with DSCPs was revisited in 2018 
(draft-briscoe-tsvwg-l4s-diffserv-00), after RFC8311 enabled such a 
deployment experiment using ECT(1).  That which explains how the two 
approaches interact, how they can be arranged to complement each other 
and in which cases one can stand alone without needing the other.

Gorry

On 24/03/2021 11:01, Pete Heist wrote:
> I'll just add to the sentiment that I think the use of DSCP is still
> worthy of consideration. Beyond the use of a single DSCP on all
> traffic, there may be other alternatives that address at least some of
> the concerns in B.4.
>
> Pete