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

David Collier-Brown <> Thu, 05 March 2015 13:14 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id 0A4461A88F8 for <>; Thu, 5 Mar 2015 05:14:07 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -0.101
X-Spam-Status: No, score=-0.101 tagged_above=-999 required=5 tests=[BAYES_40=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_NONE=-0.0001] autolearn=ham
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id yK5AL3pSzP_D for <>; Thu, 5 Mar 2015 05:14:05 -0800 (PST)
Received: from ( []) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 393B21A8729 for <>; Thu, 5 Mar 2015 05:14:05 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=s2048; t=1425561244; bh=QtDIBrAH0/AVyoSzOLci8YDsswpnQiyTWGKSD578acc=; h=Date:From:Reply-To:To:Subject:References:In-Reply-To:From:Subject; b=YlGu+pZxmBwxHlJnI24/cugVsHlYyqCF6lKU1jRYBdEm3RgXvo7RoXaVRIxfXqdt3+UVv9YnZJ1TpHdkwu1yvOl9PkF1CvS+ZUBHMe7mWdGkjzkiAwpwuCQK7nawQDNrcAGjFCytaKQ1CI27ZdA3nPDrC0pqowJiFEWojvZeiZm5sA8JsFLkaBtOQ+tuuPE7x/+O1oO3II+5LbBzCEHR4KR44P7C3pBT9LeEKfwmjpCiqT8kV2Ipm0a5sFn4fSfIUhW7TaWrtId8CMqeTSdeaLiYjTiydZpNQKjTl9nemND315HEX5pt4HfMMkMQFuDLGFtGsjdzGMsakWURncHf0g==
Received: from [] by with NNFMP; 05 Mar 2015 13:14:04 -0000
Received: from [] by with NNFMP; 05 Mar 2015 13:14:04 -0000
Received: from [] by with NNFMP; 05 Mar 2015 13:14:04 -0000
X-Yahoo-Newman-Property: ymail-3
X-YMail-OSG: oZ4MxCAVM1mGyslGWOVFPKcgV_MpWlevavPeBGQoduhsouO fua_jK708iEz4WB3iXvbbKsIMLh6xaNeC1pz9F6EgYirEsAu38hKnHoNiVuI 9K3g1nIbjjLjW30yypuFtBV6D0Vqscl9bwnyps1huXe3ob6vpU4CJQoS.4Rn 8nhSBTcO4LL1ygxikco0xYx4f96_aLqPn5ebyJ9Cwm83MYVmSdzwf.LrfKyV j6Yf0P1yW0DX1LFt3Cf0zD.zgiEQ5mXjwfW8uQcIuqYtnuoapXEJSxLJJ026 eV2dvt2oTrLVGSN4_AYsgTsLRNEuDTMkcOC8kIfHdH5Zkwh8y0Le7df0I2J0 ewRvt5ZFqaOLxLQODpcJOjZI1LRkFe1QugKCTNYt6fN5qahzbcCB1XeB6B0S ABGSYefjp19dEib7F3MtoRngC8ArW0SLBmDG61NR93dF5CxHtdqKkUIEIgix jJm635klypsRYrF0jpAN2NupXbORtsj2sQyCSh6Xof70MSpaO1YZQ.pIWDHx gk48sl3PjbPFMwGn6mbU6qqJYHvyFgMQxU0qT
X-Yahoo-SMTP: sltvjZWswBCRD.ElTuB1l9j6s9wRYPpuyTNWOE5oEg--
Message-ID: <>
Date: Thu, 05 Mar 2015 08:14:00 -0500
From: David Collier-Brown <>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0
MIME-Version: 1.0
References: <> <473265656416337848@unknownmsgid> <> <>
In-Reply-To: <>
Content-Type: text/plain; charset="windows-1252"; format="flowed"
Content-Transfer-Encoding: 7bit
Archived-At: <>
Subject: Re: [aqm] [Bulk] Re: the cisco pie patent and IETF IPR filing
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: "Discussion list for active queue management and flow isolation." <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Thu, 05 Mar 2015 13:14:07 -0000

On 03/04/2015 04:42 AM, David Lang wrote:
> The question is how much of a burst should the buffer be able to 
> handle? Right now buffers routinely hold 10+ seconds worth of traffic 
> (and Dave T showed the airline system buffering 10+ MINUTES of traffic)
> The problem is that if you buffer too much, you break the TCP link 
> speed probing, and if you buffer even more you end up with the sender 
> genrating a new packet to deliver while you still are buffering the 
> old one.
> Buffers need to hold less than one second worth of traffic, and 
> emperical testing is showing that much less is desirable (Others can 
> post more exact numbers, but I belive that somewhere between 1/100 of 
> a second and 1/10 of a second is a reasonable range)

I'd suggest that buffers are there to hold unexpected bursts of traffic 
above the steady state maximum.  This can happen for several reason:
1)  due to the sender sending an unexpected wodge, either at startup or 
due to a bug, or
2) after a period of non-transmission, due to something in the pipe 
slowing us down momentarily.

Either case of (1)  should be throttled, so bugs and 
super-fat-start-eats-the-network can be avoided (;-))
Case of (2) need to be buffered, in an amount that handles either the 
average/expected burstyness of the link, or handles the predictable 
burst when one stream on the link slows down and then catches up.

Let's say the link varies by +/- 1 packet/second: we should have 
buffering for 2, probably for 3 and definitely not for any bigger sigma.


David Collier-Brown,         | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest           |                      -- Mark Twain