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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">This is my guess.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">DSL reports uses many streams from different servers to achieve these speeds.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">I’m assuming flent is a single stream, so you’re at the mercy of TCP receive windows and latency limiting how fast you can go on that single stream.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Bloat [mailto:bloat-bounces@lists.bufferbloat.net]
<b>On Behalf Of </b>Aaron Wood<br>
<b>Sent:</b> Tuesday, August 29, 2017 11:16 PM<br>
<b>To:</b> bloat <bloat@lists.bufferbloat.net><br>
<b>Subject:</b> [Bloat] different speeds on different ports? (benchmarking fun)<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I don't have a full writeup yet, but wanted to ask if people on here have run into this. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I'm seeing a disparity between flent and the dslreports speed tests. On my connection at home (Comcast 150/12), I figured it was something related to the test implementations, but minor. But on a connect at a friend with business-class
Comcast (300/12), we're seeing a huge difference. Flent can't seem to achieve more than 120Mbps, often with an early, couple-second hump at a much higher speed. But dslreports' speed tests gets the full 300Mbps.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">In looking closer at my connection, with sqm (cake) turned off, I'm seeing ~180Mbps download with 500ms of bufferbloat when I use the dslreports test (<a href="http://www.dslreports.com/speedtest/20805152">http://www.dslreports.com/speedtest/20805152</a>).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Yet flent can't come close to that, even with the tcp_12down test:<o:p></o:p></p>
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<p class="MsoNormal"><img border="0" width="545" height="209" style="width:5.677in;height:2.177in" id="_x0000_i1025" src="cid:image002.png@01D332B6.95FED960"><br>
<o:p></o:p></p>
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<p class="MsoNormal">The current hypothesis that we have is that this is due to either traffic class, or the ports that traffic are running on. I've ruled out the ping streams, as a parallel set of netperf tcp_maerts downloads has the same 120Mbps roof.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">It would be interesting if we could run some netperf tests using port 80/443 for the listening socket for the data connection (although if doing deep-packet inspection, we might need to use an actual HTTP transfer).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-Aaron<o:p></o:p></p>
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