From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-x231.google.com (mail-ob0-x231.google.com [IPv6:2607:f8b0:4003:c01::231]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id E076121F32B for ; Sat, 28 Feb 2015 09:58:54 -0800 (PST) Received: by mail-ob0-f177.google.com with SMTP id wp18so23513419obc.8 for ; Sat, 28 Feb 2015 09:58:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=HmiSEc6Zx51R17hpHu5wwhkzNuMFW1TfxV5UKB6gM30=; b=cmWumI3yZ5SUsKuxPocooHIFvvm0ltri7HwTHx/2WTtWrsGDi01lxNAzf+cd+tyTFk CiQS7cNPAomEd07T6pMOM7zVzCYSgTRlvJwQkY2ZG4bqHcyspjUDVQaxmXP/Zqa8Dtmw RPsUUP6zd0gzQYaIngfE5KpoXsFOZQl74885vlNI+niqyaCstw3bINajE3G7ylVNuxVg Vb4EESVUJYRuNe2hvspmWJnWTmzwF0HRL7aGJ4XXI1jY8PPb1PYYbmJglY1ICsQq5xu2 aiRucMQH2o5gaW39E9kYEYsQ/oj1IE+33FAK1Y/nPso12JM4Nctf4oa+A7xzcLGL0T1/ JQ2g== MIME-Version: 1.0 X-Received: by 10.182.98.164 with SMTP id ej4mr14258714obb.0.1425146333898; Sat, 28 Feb 2015 09:58:53 -0800 (PST) Received: by 10.202.51.66 with HTTP; Sat, 28 Feb 2015 09:58:53 -0800 (PST) In-Reply-To: References: Date: Sat, 28 Feb 2015 09:58:53 -0800 Message-ID: From: Dave Taht To: divya singla , Tom Henderson Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: "codel@lists.bufferbloat.net" Subject: Re: [Codel] fq_Codel vs Sfq_Codel X-BeenThere: codel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: CoDel AQM discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 28 Feb 2015 17:59:23 -0000 sfq_codel in ns2 is derived more from SFQ than DRR, and there are several substantial differences, although sfq_codel can be almost, but not quite, configured to act the same as the dual DRR version that is in the actual, shipping, fq_codel. The version of DRR fq_codel uses is more similar to "DRR+" and "DRR++", but is uniquely it's own. You have to use sfq_codel VERY carefully in the ns2 version, as the ability to correctly generate a five tuple hash is not there. Correctly generating a 5 tuple is almost, but not quite, in the ns3 version, last I looked, and that ns3 version is MUCH closer to the actual fq_codel version deployed in the field, but still not quite the same thing. I have kind of lost track as to the right ns2 and ns3 versions to start from, also. Tom? in terms of setting up realistic scenarios: A common (actually, nearly universal) change to fq_codel in the field at low bandwidths (below 50mbit) is to use a reduced quantum (300 bytes). I don't remember how to do that right in the ns2 version. It has, after all, been 3 years of no interest from the academic community. Also the codel target and interval need to be tuned slightly, at below 2.5mbits to account for a single full length packet at those speeds. I am delighted by the sudden upsurge in interest in the *fq_codel versions but I would certainly appreciate more efforts on making the underlying simulations actually match the deployment, before everyone goes off writing papers again. See sch_fq_codel.c in the linux distributions since 3.6, see also codel.h there, and compare against what you have for ns2 and ns3. I completely lack time or funding to make sims match the (much better reality) at this point. Worst case, I would encourage you to test the sims verses the deployed code with the same exact tests, so you can see what differences exist. On Sat, Feb 28, 2015 at 9:34 AM, divya singla w= rote: > can anybody tell me is there any difference between fq_Codel and Sfq_Code= l? > > > > _______________________________________________ > Codel mailing list > Codel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/codel > --=20 Dave T=C3=A4ht Let's make wifi fast, less jittery and reliable again! https://plus.google.com/u/0/107942175615993706558/posts/TVX3o84jjmb