Bob, Thanks, this is interesting. As you probably know this patent has come to the attention of the Linux community and caused some concern: https://lwn.net/Articles/784125/ so it's useful to know of a potential workaround.
Alex On Mon, Mar 25, 2019 at 1:34 AM Bob Briscoe <i...@bobbriscoe.net> wrote: > Alex, inline... > > On 24/03/2019 21:15, alex.b...@ealdwulf.org.uk wrote: > > > > Hi Bob, > > > > > > I note that all the non-dependent claims of US20170019343A1 (claims > 1,14,22) seem to assume use of the proportional-integral controller (Note, > I am not a lawyer, and especially not a patent lawyer). > Yes, as I understand it, Nokia's intention with this filing was to cover > use of the PI controller in particular, in combination with various > other ideas. > > > In Appendix B of draft-briscoe-tsvwg-aqm-dualq-coupled, an alternate > algorithm 'Curvy RED' seems to replace PI, but it is noted that 'the Curvy > RED algorithm has not been maintained to the same degree as the DualPI2 > algorithm '. > > > > Can you comment on whether the Curvy RED algorithm could form a > non-patent-encumbered dualq? In particular: > > - Why wasn't curvy red further developed? Was it found to contain some > deficiency? Are you intending to present it as an alternative? > We just didn't develop it further, cos we were getting better results > with PI2. However, I am aware of a hardware implementation based on > Curvy RED going on at the moment, and you will see there have recently > been review comments on that Curvy RED appendix on the list. > > So, even tho PI might be better, Curvy RED (or another AQM) might be > preferable for other reasons that performance (e.g. ease of > implementation, or similarity to an existing hardware implementation). > > And indeed, there's nothing to stop anyone using other AQMs, either to > work round the IPR, or because they're preferable in their own right - > the DualQ Coupled AQM is intentionally a framework into which you drop 2 > AQMs. > > > - Does Curvy RED actually completely replace PI? > Yes. > > - Can we have reasonable assurance that no patents will surface > covering Curvy RED? > Well, I developed the idea of Curvy RED and I / my employer (BT) did not > file any IPR at the time. I got approval to publish a tech report > jointly with Al-Lu. http://bobbriscoe.net/pubs.html#CRED-insights > > That was May 2015, so given nothing has surfaced by now, there can't be > anything from that time from us (where us = Al-Lu & BT). > > Of course, I cannot guarantee that there is not another patent in the > system from some other random company that my searches haven't found. > There are large numbers of AQM patents. Also, I cannot guarantee that an > implementer working now isn't filing patents around their > implementation. All we can do is publish as much as possible as early as > possible to try to keep some areas of the field open. > > > Bob > > > > Thanks, > > Alex > > > > > > On Wednesday, March 20, 2019, 11:29:38 PM GMT, Bob Briscoe < > i...@bobbriscoe.net> wrote: > > > > > > > > > > > > > > 1/ In 2016, I arranged for the hire of a patent attorney to undertake > the unusual step of filing a third party observation with the European > Patent Office. This went through Al-Lu's patent application claim by claim > pointing to prior art and giving the patent examiner all the arguments to > reject each claim. However, the examiner chose to take very little note of > it, which was disappointing and costly for us. The main prior art is: > > Gibbens, R.J. & Kelly, F.P., "On Packet Marking at Priority > Queues," IEEE Transactions on Automatic Control 47(6):1016--1020 (June 2002) > > The guys named as inventors in AL-Lu's filing published a paper on PI2 > with me, in which we included a citation of this Gibbens paper as > inspiration for the coupling. The Gibbens paper was already cited as > background by other patents, so the EPO has it in their citation index. > > > > The coupling was also based on my prior research with Mirja before I > started working with the guys from Al-Lu in the RITE European Collaborative > project. we had to go through a few rejections, but Mirja and I finally got > this work published in 2014 - still before the priority date of the Al-Lu > patent application: > > Kühlewind, M., Wagner, D.P., Espinosa, J.M.R. & Briscoe, B., "Using > Data Center TCP (DCTCP) in the Internet," In: Proc. Third IEEE Globecom > Workshop on Telecommunications Standards: From Research to Standards > pp.583-588 (December 2014) > > > > 2/ The only claim that I could not find prior art for (in the original > EU filing) was a very specific claim about using a square root for the > coupling. The Linux implementation runs this the other way round so that it > only has to do a squaring. So I figured we were safe from that. > > > > However, until just now, I had not noticed that Al-Lu has > retrospectively re-written the claims in the US patent and in the EU patent > application to claim this the other way round - as a squaring. And to claim > the two random number trick. Both restructuring to use a squaring and the > two random number trick were definitely my ideas (while working for BT in a > collaboration with Al-Lu). I have emails to prove this (from memory they > were actually both in the same email). This is important, because a patent > has to be about mechanism, not algorithm. > > > > 3/ This is a positive development. It means this patent is on very shaky > legal ground. I have been trying to put pressure on Nokia to license this > royalty free. But now I see what they have done, I am going to have to get > a different type of legal advice. > > > > > > -- > ________________________________________________________________ > Bob Briscoe http://bobbriscoe.net/ > >
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