From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from eu1sys200aog107.obsmtp.com (eu1sys200aog107.obsmtp.com [207.126.144.123]) by huchra.bufferbloat.net (Postfix) with SMTP id 89F1E2021A8 for ; Tue, 9 Jul 2013 10:39:04 -0700 (PDT) Received: from mail-lb0-f169.google.com ([209.85.217.169]) (using TLSv1) by eu1sys200aob107.postini.com ([207.126.147.11]) with SMTP ID DSNKUdxKtdHkkwOQmWKuYhzEeUUqIaeTjdFy@postini.com; Tue, 09 Jul 2013 17:39:04 UTC Received: by mail-lb0-f169.google.com with SMTP id d10so4933405lbj.14 for ; Tue, 09 Jul 2013 10:39:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:from:date:message-id:subject:to:content-type :x-gm-message-state; bh=zfaUBKNavj8IAInOtjioE/o1CKZD14wRVnwC77NlcPY=; b=J64umRSYqAzyP9nxAUz2WcqlEf8UOKDIHJhVRE767MywFTtejmSYwWxmFL5g9wMPFd KIO+sewUQj6jPJceV0+b+TzPqlN6rIAEYxaUsgMxzWKh9CDjC3/5Vtp4vSqSWNaBtjUu Bmmv/J7M/erDAx04LbulUywteYwBytrPQ3WcZ0yHw1ULiv1wKrTScXwVsoswmW8cg4Ey cGKpuQDg+WlvZ/kN4i9Fd+xNi5TTInVik88wU+35PIKM3Ew8ly2l8LNKyUQzTJ5C9Zgv SmqoyGGK6Oq0KSbkKVB8+FA1JObHb5VCS2rrMclR31aNqCgT8imi1uW/yTZX43iB3WS3 s1RQ== X-Received: by 10.112.76.106 with SMTP id j10mr13155603lbw.19.1373391540887; Tue, 09 Jul 2013 10:39:00 -0700 (PDT) X-Received: by 10.112.76.106 with SMTP id j10mr13155595lbw.19.1373391540580; Tue, 09 Jul 2013 10:39:00 -0700 (PDT) MIME-Version: 1.0 Received: by 10.114.9.33 with HTTP; Tue, 9 Jul 2013 10:38:40 -0700 (PDT) From: Jaume Barcelo Date: Tue, 9 Jul 2013 19:38:40 +0200 Message-ID: To: bloat@lists.bufferbloat.net Content-Type: text/plain; charset=ISO-8859-1 X-Gm-Message-State: ALoCoQn4d9jBA5Wxa3iD81viKsPJXCI9YX+TeGAGpXrQ0RW7fu65fPd+BBpvDkYL0Y0jc4PZx3f6DFAj1vNsq5eMSo7kQn90xLtY2B5Fdl0kwQzfu61zVr4CRtFfkG8wU1iJOhaNqrfQPebCDIln6JqJJbXXAALqVpZy7Tbi9vAWOoKJMGBAZJg= Subject: [Bloat] sweet tcp 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: Tue, 09 Jul 2013 17:39:05 -0000 Hi, I was explaining the bufferbloat problem to some undergrad students showing them the "Bufferbloat: Dark Buffers in the Internet" paper. I asked them to find a solution for the problem and someone pointed at Fig. 1 and said "That's easy. All you have to do is to operate in the sweet point where the throughput is maximum and the delay is minimum". It seemed to me that it was a good idea and I tried to think a way to force TCP to operate close to the optimal point. The goal is to increase the congestion window until it is larger than the optimal one. At that point, start decreasing the congestion window until is lower than the optimal point. To be more specific, TCP would be at any time increasing or decreasing the congestion window. In other words, it will be moving in one direction (right or left) along the x axis of Fig. 1 of Getty's paper. Each RTT, the performance is measured in terms of delay and throughput. If there is a performance improvement, we keep moving in the same direction. If there is a performance loss, we change the direction. I tried to explain the algorithm here: https://github.com/jbarcelo/sweet-tcp-paper/blob/master/document.pdf?raw=true I am not an expert on TCP, so I decided to share it with this list to get some expert opinions. Thanks, Jaume