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

KK <> Wed, 04 March 2015 09:01 UTC

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Date: Wed, 04 Mar 2015 01:01:19 -0800
From: KK <>
To: Vishal Misra <>, Dave Taht <>
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Thread-Topic: [aqm] the cisco pie patent and IETF IPR filing
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Subject: Re: [aqm] the cisco pie patent and IETF IPR filing
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I think a combination of PI/PIE/fq_codel with ECN would enable us
a) be less dependent of the physical amount of buffering that is
implemented on the intermediate devices
b) allow us to use buffering for what it is meant to do - ride out
transient variations in traffic, at points where there is a mismatch in
available capacity
c) allow us to support different types of links, including wireless lossy
d) as we wrote in the ECN RFC, allow even short-lived transfers to not
K. K. Ramakrishnan
Dept. of Computer Science and Engineering
University of California, Riverside
Rm. 332, Winston Chung Hall
Tel: (951) 827-2480
Web Page:

On 3/4/15, 12:17 AM, "Vishal Misra" <> wrote:

>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
>> 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!
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