Thank you. I too was puzzled but didn't take the time to delve deeper. On Fri, Jun 14, 2024 at 4:05 AM Jonathan Morton wrote: > > On 14 Jun, 2024, at 2:40 am, Dave Taht via Cake < > cake@lists.bufferbloat.net> wrote: > > > > > https://www.tu-ilmenau.de/fileadmin/Bereiche/IA/vsbs/Publikationen/2024/SSK_NOMS24_AdaptiveAQM_Authors-version.pdf > > I don't understand their test methodology. I mean that literally. > > Their results indicate queue delays in the region of one whole second. > This is wildly different from the target delays of any of the AQMs tested. > In fact, their results for COBALT are above the trigger for BLUE activity > (which they also helpfully listed in their configuration table). One > obvious conclusion is that COBALT's lower queue delays and higher loss > rates in their results are precisely due to relying on the BLUE component. > But that is most certainly not the intended operating regime for COBALT - > BLUE is provided as a failsafe, not as a primary congestion signalling > mechanism. > > They state a link rate of 2Gbps, and a variety of flow rates, the highest > of which is 10Mbps. Even if we multiply the latter by the number of > clients (100), the 2Gbps link is not saturated. If there's a separate flow > between each client-server Cartesian product, and the clients are each > limited to a 10Mbps link with its own AQM instance, then we should expect > AQM activity to be capable of keeping the queue delay down to about 20ms > (5x a small number of MTUs), which is 50x better than their typical > reported results. > > I can only conclude that, for whatever reason, they have constructed a > traffic scenario (the details of which are not adequately reported in the > paper) which induces an extreme level of congestion, which of course the > conventional AQMs have some trouble with handling (but COBALT does better > on, due to BLUE activity). They then introduce their own AQMs to this > scenario, and report that they do better on a couple of metrics (but are > still very bad on the others). > > Overall, this paper does not provide any information of interest. > > - Jonathan Morton -- Artists/Musician Campout Aug 9-11 https://www.eventbrite.com/e/healing-arts-event-tickets-928910826287 Dave Täht CSO, LibreQos