<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I have not been following Bufferbloat but a colleague forwarded to me the latest post from Dave Täht about FQ_Codel. It is good to see the virtues of fair queuing are being rediscovered. <br><br>I think the work by Suter and co-authors on FQ in high capacity routers is particularly relevant:<br><br>B. Suter, T. Lakshman, D. Stiliadis, A. Choudhury, Buffer Management Schemes<br>for Supporting TCP in Gigabit Routers with Per-Flow Queuing, IEEE Journal in<br>Selected Areas un Communications, August 1999. (<a href="http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=772451">http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=772451</a>)<br><br>They may have been the first to introduce "head drop". Actually they advocated dropping from the front of the flow queue with longest backlog (FQ_LQD). I am not sure why a more sophisticated AQM, like RED, ARED or Codel, is better than longest queue drop.<br><br>Another advantage of FQ_Codel highlighted in the report by Toke Høiland-Jørgensen (notified on the list) is to give priority to packets of newly active flows. This idea was already proposed in our papers:<br><br>A. Kortebi, S. Oueslati and J. Roberts. Cross-protect: implicit service differentiation and admission control, IEEE HPSR 2004, Phoenix, USA, April 2004. <br>A. Kortebi, S. Oueslati, J. Roberts. Implicit service differentiation using Deficit Round Robin, Proceedings of ITC 19, Beijing, August 2005. <br><br>I have long been advocating per flow fairness as the basis of effective traffic control so I hope you won't mind me recalling this prior work.<br><br>Jim Roberts<br><br></body></html>