Re: [aqm] the cisco pie patent and IETF IPR filing

Vishal Misra <> Wed, 04 March 2015 08:17 UTC

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From: Vishal Misra <>
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Date: Wed, 04 Mar 2015 03:17:11 -0500
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To: Dave Taht <>
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Subject: Re: [aqm] the cisco pie patent and IETF IPR filing
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Hi Dave,

Thanks for your email. A few quick points:

- I have actually sent a note already to someone on the Cisco PIE team
about the error in the IETF IPR filing and am sure they will get it
corrected. You have helpfully dug out the actual patent application
and it appears that one digit got inadvertently changed in the Cisco
IETF IPR declaration of the patent application.

- I wish I had a "marketing department" that would do stories for me
:-). I work at Columbia University and that story that you point out
was done by a writer at the UMass-Amherst engineering school as an
example of academic research having practical impact. There is an
urgent need to support more academic research and I think stories like
this one support the cause.

- Indeed neither me nor any of the other PI authors had any idea of
the PIE work. I discovered it accidentally when I was at MIT giving a
talk on Network Neutrality and Dave Clark mentioned Cisco's PIE and
DOCSIS 3.1 to me. I later read up on PIE and was pleasantly surprised
that our PI work from more than a decade back evolved into it.

- I had contributed the PI code to Sally Floyd back in 2001 and it has
been part of ns2 for the longest time ( It shouldn't be
difficult to adapt that for a Linux implementation and I am happy to
help anyone who wishes to try it. Maybe that might affect your loyalty
to fq_codel.


> On Mar 4, 2015, at 1:07 AM, Dave Taht <> wrote:
> Two items:
> A) The IETF IPR filing points
> to the wrong patent: 13/874,500. A google search for that patent
> number brings up"
> It is ironically relevant to the discussions at hand, as that one concerns:
> Abstract:
> "Provided are methods of increasing the tolerance of a plant to
> abiotic stresses and/or increasing the biomass and/or increasing the
> yield of a plant by expressing within the plant an exogenous
> polynucleotide homologous to SEQ ID NO:13."
> ... As I consider myself a near-vegetable, and am 40 pounds heavier,
> and not responding particularly well to antibiotics, after
> participating for the past several years on all the ietf mailing lists
> I just got off of. I am sure that upon acceptance of pie in the ietf,
> that making that particular patent more generally available for all to
> use would probably have similar effects on others.
> The correct patent number for PIE, 13/874,600, is here:
> I would appreciate that the IPR filing be corrected.
> In the meantime, here's some more great NSFW george carlin routines!
> B) Vishal Misra (author of PI) gave me pointers to his PI papers
> recently (and he had NO idea at all his work was used for pie! - he
> got his marketing department to issue a press release about it:
> )
> I usually have a pretty strict policy about never reading patents, but
> I read all those papers [1], and both! patents above. I had not fully
> realized that the PI-AQM work went as far back as 2001. The PI update
> equation and the PIE update equation, look pretty darn similar, just
> the meanings of two variables, changed.
> C) I am kind of curious if any working code for the original PI
> algorithm exists for linux?
> D) oh, never mind, I will blog about the rest one day.
> [1] still prefer fq_codel.
> --
> Dave Täht
> Let's make wifi fast, less jittery and reliable again!