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<p class="MsoPlainText">Hi Bob,<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Thanks for your response, I think it helped clarify some important things<o:p></o:p></p>
<p class="MsoPlainText">for me.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">The point about starvation especially was a good one I hadn't fully<o:p></o:p></p>
<p class="MsoPlainText">considered, and I agree if SCE-based implementations can’t demonstrate a<o:p></o:p></p>
<p class="MsoPlainText">solution, that would be a major problem with the SCE approach for signaling.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">And sorry for my slow response, I ended up restarting a few times to try to<o:p></o:p></p>
<p class="MsoPlainText">dodge ratholes. (Plus some day-job duties, apologies...)<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">I found it a bit challenging to avoid the ratholes effectively, so I'm<o:p></o:p></p>
<p class="MsoPlainText">thinking maybe the right move is to set up a testbed. Maybe playing with<o:p></o:p></p>
<p class="MsoPlainText">that (very cool-looking!) L4SDemo tool can either ease my concerns, or<o:p></o:p></p>
<p class="MsoPlainText">provide some more specific and detailed scenarios to address.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">I see that the source code is published now at<o:p></o:p></p>
<p class="MsoPlainText">https://github.com/L4STeam/l4sdemo (thanks Olivier!). So I’ll try to<o:p></o:p></p>
<p class="MsoPlainText">bring that up at some point, time permitting, in hopes it makes the<o:p></o:p></p>
<p class="MsoPlainText">comments and questions more productive.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">One meta-point I wanted to make:<o:p></o:p></p>
<p class="MsoPlainText"> "In trying to find a compromise, you've taken the fire that is really<o:p></o:p></p>
<p class="MsoPlainText"> aimed at the inadequacy of underlying SCE protocol - for anything<o:p></o:p></p>
<p class="MsoPlainText"> other than FQ. If the primary SCE proponents had attempted to<o:p></o:p></p>
<p class="MsoPlainText"> articulate a way to use SCE in a single queue or a dual queue, as you<o:p></o:p></p>
<p class="MsoPlainText"> have, that would have taken my fire."<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">I think "fire" here is a potentially harmful metaphor--I don't take your<o:p></o:p></p>
<p class="MsoPlainText">comments as an attack or this discussion as a battle, but rather a<o:p></o:p></p>
<p class="MsoPlainText">collaborative attempt to reach a common goal of a better internet.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">I hope my comments on this are received the same way, even where we don't<o:p></o:p></p>
<p class="MsoPlainText">see eye to eye yet. While both ideas can't be the best use of ECT(1) at<o:p></o:p></p>
<p class="MsoPlainText">the same time, I take this discussion as an effort to reach a common and<o:p></o:p></p>
<p class="MsoPlainText">complete understanding of the issues at hand, so that we can hopefully<o:p></o:p></p>
<p class="MsoPlainText">agree on the best approach in the end (or if we can't get there, maybe we<o:p></o:p></p>
<p class="MsoPlainText">can at least agree on the underlying reasons we don't agree).<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">With that said, a few brief points I think really should be raised:<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">1. "non-problem" is an unreasonably strong conclusion to reach from a<o:p></o:p></p>
<p class="MsoPlainText">snapshot failure to detect any single-queue marking AQMs.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">We know that tc-pie exists in widely deployed systems, supports ECN, and<o:p></o:p></p>
<p class="MsoPlainText">could be turned on at any moment by anybody, and we also know there's an<o:p></o:p></p>
<p class="MsoPlainText">increased interest in ECN since Apple and Linux got it turned on on<o:p></o:p></p>
<p class="MsoPlainText">endpoints. Even if we measure everything today, it’s hard to be sure this<o:p></o:p></p>
<p class="MsoPlainText">wouldn’t impact an in-progress rollout that someone has been working toward<o:p></o:p></p>
<p class="MsoPlainText">for their network with proper due diligence, and following IETF advice<o:p></o:p></p>
<p class="MsoPlainText">faithfully.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">I think if the intent is really to deploy this experiment under the claim<o:p></o:p></p>
<p class="MsoPlainText">that's a non-problem, it should be called out in the docs as a risk factor,<o:p></o:p></p>
<p class="MsoPlainText">and consensus should probably be explicitly checked on that point. It also<o:p></o:p></p>
<p class="MsoPlainText">probably would be polite to update RFC 7567's advice in section 4, since it<o:p></o:p></p>
<p class="MsoPlainText">seems like this position would invalidate (or at least add nuance) to<o:p></o:p></p>
<p class="MsoPlainText">several of the SHOULDs given there, recommending the use of ECN.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">2. “does not starve a classic flow, but can be highly unequal” is also<o:p></o:p></p>
<p class="MsoPlainText">perhaps too low a bar to consider a non-problem, and also seems like maybe<o:p></o:p></p>
<p class="MsoPlainText">it deserves to be called out as a risk factor.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">3. One more meta-point: the sales-y language makes the drafts hard to<o:p></o:p></p>
<p class="MsoPlainText">read for me, so please forgive some of my confusion. I'm having a hard<o:p></o:p></p>
<p class="MsoPlainText">time distinguishing the claims that are well-supported by test results in a<o:p></o:p></p>
<p class="MsoPlainText">realistic experimental design from some of the claims that are more forward-<o:p></o:p></p>
<p class="MsoPlainText">looking or speculative.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">(4. There’s one other point I’ll mention in response to Ingemar’s comment,<o:p></o:p></p>
<p class="MsoPlainText">about performance being sufficient to drive adoption, and the difference<o:p></o:p></p>
<p class="MsoPlainText">between what’s achievable with classic ECN and what’s achievable with L4S,<o:p></o:p></p>
<p class="MsoPlainText">but that thread is perhaps a better venue for discussing it.)<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Best regards,<o:p></o:p></p>
<p class="MsoPlainText">Jake<o:p></o:p></p>
<pre><o:p> </o:p></pre>
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