[Ecn-sane] ect(1) queue selector question

[Sebastian Moeller]

Hi Dave,


> On Feb 20, 2021, at 20:27, Dave Taht <dave.taht at gmail.com> wrote:
> 
> I note that I have done my best to stay out of this for a while, so
> long that I (thankfully) mis-remember various aspects of the debate.
> Today I have a question about l4s vs SCE as it's come up again.
> 
> l4s uses both a dscp codepoint AND ect(1) to indicate dctcp style
> congestion control
> is in use, and also can dump other protocols into that queue lacking
> any ecn markings.

	Mmmh, according to the L4S internet drafts, L4S does not want to use a DSCP at all. Interestingly enough, Greg White is proposing a related internet draft about the NQB PHB and DSCP that sounds awfully like the missing DSCP in the L4S drafts. IMHO if the whole thing would be guarded behind a DSCP I would be less annoyed by the design and process of L4S....

> 
> SCE proposes to use ect(1) as an indicator of some congestion and does
> not explictly
> require a dscp codepoint in a FQ'd implementation.

	Pretty much. I do think that a demonstration using an additional DSCP to create a similar HOV lane for SCE would have gone miles in convincing people in the WG that L4S might really not be as swell as its proponents argue, IMHO it won the day more with its attractive promise of low latency for all instead of what it delivers.

> 
> Do I have that right? Now, my question was, simply, in MPLS or X-G are
> they out of bits, and
> that's why they want to use up this one in L4S?

	I do not think that MPLS folks are a driver in all of this, no? No idea what X-G is. 

> 
> -- 
> "For a successful technology, reality must take precedence over public
> relations, for Mother Nature cannot be fooled" - Richard Feynman
> 
> dave at taht.net <Dave Täht> CTO, TekLibre, LLC Tel: 1-831-435-0729
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