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Re: [tsvwg] Neal Cardwell's rationale for supporting ECT(1) as an input/L4S signal

Jonathan Morton <chromatix99@gmail.com> Tue, 12 May 2020 20:39 UTC

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From: Jonathan Morton <chromatix99@gmail.com>
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Date: Tue, 12 May 2020 23:38:59 +0300
Cc: Jeremy Harris <jgh@wizmail.org>, tsvwg IETF list <tsvwg@ietf.org>
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To: Neal Cardwell <ncardwell@google.com>
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Subject: Re: [tsvwg] Neal Cardwell's rationale for supporting ECT(1) as an input/L4S signal
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> On 12 May, 2020, at 11:29 pm, Neal Cardwell <ncardwell@google.com> wrote:
> 
>> The shallow queues referred to are intended for deployment in tightly
>> controlled datacentre environments, where the typical path RTT is measured in
>> microseconds rather than milliseconds. It would not be surprising if a
>> transport passing through such a queue as part of a typical Internet path of
>> many milliseconds experienced poor utilisation.
> 
> I think the issue is that such paths do not currently suffer from
> throughput problems, but could if they attempt to participate in an
> SCE conversation.

Except that they *do* already suffer from throughput problems if they attempt to participate in an RFC-3168 ECN conversation, to precisely the same extent, and for precisely the same reasons.

 - Jonathan Morton

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