Re: [tsvwg] SCReAM (RFC8298) with CoDel-ECN and L4S

Jonathan Morton <chromatix99@gmail.com> Tue, 10 March 2020 09:43 UTC

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From: Jonathan Morton <chromatix99@gmail.com>
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Date: Tue, 10 Mar 2020 11:43:23 +0200
Cc: "tsvwg@ietf.org" <tsvwg@ietf.org>, Ingemar Johansson S <ingemar.s.johansson@ericsson.com>, "iccrg@irtf.org" <iccrg@irtf.org>
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To: Ingemar Johansson S <ingemar.s.johansson=40ericsson.com@dmarc.ietf.org>
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Subject: Re: [tsvwg] SCReAM (RFC8298) with CoDel-ECN and L4S
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> On 10 Mar, 2020, at 10:02 am, Ingemar Johansson S <ingemar.s.johansson=40ericsson.com@dmarc.ietf.org> wrote:
> 
> I recently updated the readme on the SCReAM github with a comparison with SCReAM in three different settings
> 	• No ECN
> 	• CoDel ECN
> 	• L4S
> https://github.com/EricssonResearch/scream#ecn-explicit-congestion-notification
>  
> Even though it is more than a magnitude difference in queue delay between CoDel-ECN and L4S, it is fair to say that these simple simulations should of course be seen as just a snapshot. 
> We hope to present some more simulations with 5G access, and not just simple bottlenecks with one flow, after the summer. 

Looking at the throughput numbers, I also notice the L4S case has less than half the throughput of the Codel ECN case.  That seems like a significant tradeoff for the lower delay numbers.  In fact, even though the throughput *before* the capacity reduction is less than the capacity *after* it, the throughput is still halved when the capacity reduces.

This seems like something you might still want to look into.

 - Jonathan Morton