From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from uplift.swm.pp.se (swm.pp.se [212.247.200.143]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id C29903B2A0 for ; Wed, 21 Sep 2016 07:28:40 -0400 (EDT) Received: by uplift.swm.pp.se (Postfix, from userid 501) id 6268FA3; Wed, 21 Sep 2016 13:28:39 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=swm.pp.se; s=mail; t=1474457319; bh=H2IzrCSpUB9++/8w50AsXo1w3hqCc85R+W7u+rxsKgg=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=p7NEovnIs8L5WDkPY7TmZjUR2EwSMDL0XXko7zth7p7Vn26e1cv/z3rzT3DoJk+T/ MedVLeHJZEChk/TdcIQrLw3em4Vg3bjMaGLviUDburGRZEyljUtrz75nXk3L+sBPW6 MAYoERJ3k+7llOGsgU8waAldzbtReyRtPw1WTpJM= Received: from localhost (localhost [127.0.0.1]) by uplift.swm.pp.se (Postfix) with ESMTP id 5DF4EA2; Wed, 21 Sep 2016 13:28:39 +0200 (CEST) Date: Wed, 21 Sep 2016 13:28:39 +0200 (CEST) From: Mikael Abrahamsson To: Alan Jenkins cc: "cerowrt-devel@lists.bufferbloat.net" In-Reply-To: Message-ID: References: <92a6ae25-530f-1837-addd-8a9ef07dd022@gmail.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) Organization: People's Front Against WWW MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Subject: Re: [Cerowrt-devel] BBR congestion control algorithm for TCP in net-next X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Sep 2016 11:28:40 -0000 On Wed, 21 Sep 2016, Alan Jenkins wrote: > That assumes the measured maximum bandwidth (over an interval of 10*rtt) > remains constant. (Say there were 100 BBR flows, then you added one > CUBIC flow to bloat the buffer). I don't have a good intuition for how > the bandwidth estimation behaves in general. My example was single CUBIC flow already existing, steady state, full speed, filling pipe and buffer with 100ms of packets, and it's not filling buffer to 110ms of packets because its window is full. There is no packet loss currently. Now you add single BBR flow. What happens, what's the ratio between BBR and CUBIC after 20 seconds of letting things settle down to new equilibrium? Consider the FIFO buffer practically infinite, or at least able to buffer 5 seconds of packets without drop. It's an interface with a single, stupid, huge FIFO buffer. -- Mikael Abrahamsson email: swmike@swm.pp.se