From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f47.google.com (mail-wg0-f47.google.com [74.125.82.47]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 597662004D7 for ; Mon, 4 Jun 2012 02:01:36 -0700 (PDT) Received: by wgbfa7 with SMTP id fa7so3098552wgb.28 for ; Mon, 04 Jun 2012 02:01:33 -0700 (PDT) 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=J1Xz16T2entx4F4pzLMFyuIbqCLdu88wv5n5PAqff6I=; b=AvLqltqMmxfPKnzQuKw2alNtY2A+uLJJ+3Q0JivU4sJ2jMM+aRZUCfgfaB9ZONFfs8 NFOQeGbcSDTbdAHfV7tDTJ54SKfSu5vZOsl0fQiVhpMcJ0JWxfksrCyCsSg8gnuKbaum g/cidv2YuIpek1DRNBowkst+pm5zYTz1GpKeis61v12G3SFrcPmnlkrGnTLH1OrTxQLv PmS5wHy+20rR7Pj/aQyxBURWs7o5qvcepA+QwFX0SNaKUyEJF1TGcYo6fCyOqAzLlJHl Ukyt8bhDbG2reESVGbmQVQwb8B4KyIj/Pflh4XoCq/eF1sxn23VIrloaxpxR6aPryGrC mUSQ== MIME-Version: 1.0 Received: by 10.216.208.80 with SMTP id p58mr9820169weo.139.1338800493127; Mon, 04 Jun 2012 02:01:33 -0700 (PDT) Received: by 10.223.103.199 with HTTP; Mon, 4 Jun 2012 02:01:33 -0700 (PDT) In-Reply-To: <970EA2AB-A3C0-4B7F-837C-F4723A1388F7@gmail.com> References: <970EA2AB-A3C0-4B7F-837C-F4723A1388F7@gmail.com> Date: Mon, 4 Jun 2012 05:01:33 -0400 Message-ID: From: Dave Taht To: Jonathan Morton Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: bloat@lists.bufferbloat.net, Eric Dumazet Subject: Re: [Bloat] Tackling bufferbloat in 3G/4G networks: A receiver-based TCP solution. X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Jun 2012 09:01:38 -0000 Encouraging. High on my list has been taking a hard look at the gsm and wifi stacks in light of fq_codel, I was planning on picking a android phone or two to hack on in the fairly near future. Any suggestions? The paper shows that vegas is still not really an improvement on cubic, and why is it nobody plays with westwood? On Sun, Jun 3, 2012 at 11:06 PM, Jonathan Morton wr= ote: > > On 4 Jun, 2012, at 4:32 am, Haiqing Jiang wrote: > >> It's really excited to find the new direction to tackle bufferbloat, on = TCP layer instead of routers (like AQM). The bufferbloat problem actually s= eems to be the most prominent, comparing with other networks. >> Therefore, we suggest the more efforts to tackling bufferbloat problem i= n cellular networks and seeking a good solution in TCP layer space. > > I read the paper quickly, and this seems to be a good use of TCP timestam= ps. =A0It thus represents an additional way to solve (or at least mitigate)= the problem in cases where the managers of bottleneck links are unwilling = or unable to implement AQM. > > If you look far enough back in the list archives - search for "Blackpool"= , for example - you'll see that I implemented a somewhat cruder solution us= ing the same basic mechanism - limiting the receive window to prevent a sin= gle TCP stream from attempting to occupy the entire buffer. =A0It was crude= r because it simply chose a window size based on the bandwidth of the flow = and an empirical relationship between bandwidth and last-mile-hop latency, = and didn't attempt to use timestamps. =A0It made a big difference for traff= ic from my local cell tower to a desktop Linux machine. > > May I ask what happens if TCP timestamps are not available for a particul= ar flow, particularly one that competes with a timestamped flow? =A0Such cr= ude stacks are probably getting less common now, but they undoubtedly still= exist. > > It would also be interesting to investigate what happens when your scheme= competes with a number of LEDBAT based flows (eg. uTP), both with and with= out AQM in place. > > =A0- Jonathan Morton > --=20 Dave T=E4ht SKYPE: davetaht http://ronsravings.blogspot.com/