<div dir="ltr">Hi Bob,<div><br></div><div>Good question. I can imagine a number of different techniques to generate and measure the traffic flows for this kind of study, and don't have any particular suggestions.</div><div><br></div><div>neal</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Aug 26, 2022 at 4:54 PM Bob McMahon <<a href="mailto:bob.mcmahon@broadcom.com">bob.mcmahon@broadcom.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi Neal,<br><br>Any thoughts on tooling to generate and measure the traffic flows BBR is designed to optimize? I've been adding some low duty cycle support in <a href="https://sourceforge.net/projects/iperf2/" target="_blank">iperf 2</a> with things like <a href="https://iperf2.sourceforge.io/iperf-manpage.html" target="_blank">--bounceback and --burst-period and --burst-period</a>. We could pull the size and period from a known distribution or distributions though not sure what to pick.<br><br>Thanks,<br>Bob<br><br>Bob</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Aug 26, 2022 at 6:36 AM 'Neal Cardwell' via BBR Development <<a href="mailto:bbr-dev@googlegroups.com" target="_blank">bbr-dev@googlegroups.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Yes, I agree the assumptions are key here. One key aspect of this paper is that it focuses on the steady-state behavior of bulk flows.<div><br></div><div>Once you allow for short flows (like web pages, RPCs, etc) to dynamically enter and leave a bottleneck, the considerations become different. As is well-known, Reno/CUBIC will starve themselves if new flows enter and cause loss too frequently. For CUBIC, for a somewhat typical 30ms broadband path with a flow fair share of 25 Mbit/sec, if new flows enter and cause loss more frequently than roughly every 2 seconds then CUBIC will not be able to utilize its fair share. For a high-speed WAN path, with 100ms RTT and fair share of 10 Gbit/sec, if new flows enter and cause loss more frequently than roughly every 40 seconds then CUBIC will not be able to utilize its fair share. Basically, loss-based CC can starve itself in some very typical kinds of dynamic scenarios that happen in the real world.</div><div><br></div><div>BBR is not trying to maintain a higher throughput than CUBIC in these kinds of scenarios with steady-state bulk flows. BBR is trying to be robust to the kinds of random packet loss that happen in the real world when there are flows dynamically entering/leaving a bottleneck.</div><div><br></div><div>cheers,</div><div>neal</div><div><br></div><div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Aug 25, 2022 at 8:01 PM Dave Taht via Bloat <<a href="mailto:bloat@lists.bufferbloat.net" target="_blank">bloat@lists.bufferbloat.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">I rather enjoyed this one. I can't help but wonder what would happen<br>
if we plugged some different assumptions into their model.<br>
<br>
<a href="https://www.comp.nus.edu.sg/~bleong/publications/imc2022-nash.pdf" rel="noreferrer" target="_blank">https://www.comp.nus.edu.sg/~bleong/publications/imc2022-nash.pdf</a><br>
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