From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x22e.google.com (mail-qt0-x22e.google.com [IPv6:2607:f8b0:400d:c0d::22e]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id C144D3B2A4 for ; Tue, 12 Jun 2018 08:00:31 -0400 (EDT) Received: by mail-qt0-x22e.google.com with SMTP id d3-v6so23363806qto.1 for ; Tue, 12 Jun 2018 05:00:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=9vJDhbkgNUsTTQolp9efMBzPV8pPM+64J9MN3/XAbyk=; b=JLgBE5LG866nXNv99JN5wyWqGSyfhyWj/09gG4LQHBR8fFl4PXLNOzYqWATHN0WlF3 ETUDJM/QmgITLXL/KkXDr4Ugo59QmM0fUe4Qhxkq547vVkfCStJKrNtw8N2XIqfyFg+6 OnJd5YeVozY2l34FczVxHDbWgEbnWCnZyS5B5yZTUbdfZMf0V6Qc/nt++splR0U9HNsc ScbOSOKkffx9QQLLf7uAwewJHIggEHsMqkpkVzLUYMt9GKs/9b5r4FpzdLoC7edMsxq9 xA8GdLk+pPZnHXOq78ArnLOTnoeqNaPAud2mkMqUxY6sQZN/6QrhdqvzTGR7+o95EdLb 7oVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=9vJDhbkgNUsTTQolp9efMBzPV8pPM+64J9MN3/XAbyk=; b=uPphwVOD63jT9XWpEyubhfxXzOIkmAiPnic4sMEsfupLn6CIrvFLxxcLAYLDH55OxH P43/n/2+a2m+fXmu2fCKVd1t/WZZXLx5QKPehjQC1frFSsqzD69P3hwdh73IOq1lMt4W lYXEmHjdMsZJu4RJxsTo9a+384ytdoeGEWpVLnbbqpz+NPYkJJY1PtuQFS7F1PaB2HG5 CGkacd6L6UF02s84Wu7071oyX22AEJ0CZZiGetsWIU1gufW2Er8bxZcBurQZu05JgNqb +CM6bSYoZGjrroBs4R1tJYIkJD56y6K/xcahaPBSl6sjS4NUWx8l6oNMZ/XD6E9WvWly dZvg== X-Gm-Message-State: APt69E1Xpw3fXTVH7aL3ANbaU6JxXapO7+ettIEr1sDvOUhvXDKA5EWm NCpffcVvsht4q1NFmBqQPobbEx9T0wHZGTpPhdc= X-Google-Smtp-Source: ADUXVKKf9hVAQq3SM/b+3mtF80X6PXDUnAvb4/iT6Toa7CgBB0rWROCMsXS19ZoEqSBfQR3ivRCZBPXGFg8a5NkWbus= X-Received: by 2002:aed:24fb:: with SMTP id u56-v6mr51187qtc.203.1528804831218; Tue, 12 Jun 2018 05:00:31 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:aed:24f0:0:0:0:0:0 with HTTP; Tue, 12 Jun 2018 05:00:30 -0700 (PDT) In-Reply-To: References: <87in6ohm30.fsf@toke.dk> <7adae673-d701-6fe0-1d47-524320d38583@gmx.net> <1b46d724-6568-c4ee-9860-86ae504434a3@kit.edu> From: Dave Taht Date: Tue, 12 Jun 2018 05:00:30 -0700 Message-ID: To: "Bless, Roland (TM)" Cc: Matthias Tafelmeier , bloat , =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Bloat] geoff huston's take on BBR X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Jun 2018 12:00:31 -0000 On Tue, Jun 12, 2018 at 4:40 AM, Dave Taht wrote: > On Tue, Jun 12, 2018 at 12:36 AM, Bless, Roland (TM) > wrote: >> Hi, >> >> Am 12.06.2018 um 07:09 schrieb Matthias Tafelmeier: >>> On 06/12/2018 02:42 AM, Toke H=C3=B8iland-J=C3=B8rgensen wrote: >>>>> https://ripe76.ripe.net/presentations/10-2018-05-15-bbr.pdf >>>> "More research needed". Naturally ;) >>>> >>>> (But yeah, good points overall) >>> >>> Interesting. Potentially, all affectuated. After having applied the BBR >>> 2.0, we might are back to Cubic? :D >> >> I don't understand what you're saying. I think Geoff tested BBR v1.0. >> Explanations for the experienced behavior can be found in our paper >> http://doc.tm.kit.edu/2017-kit-icnp-bbr-authors-copy.pdf, esp. section >> 3. Geoff's findings in the wild nicely confirm our results that were >> performed in more controlled lab settings. Important is though, that >> you always test with multiple concurrent BBR flows... > > we always do that, 'round here, with flent. Glad more folk are doing it. = :) OK, I read your paper. (It's 4am, can't sleep) My principal observation remains the same: e2e fairness is nearly hopeless on short timescales. FQ solves most of it, and even if if the rfc8290 aqm component is targetted at cubics response curve (and bbr treats it as noise), the resulting delay curve in the fq'd environment seemed to get BBR on the right track on it's first probe (except when many flows were started concurrently), but I didn't delve deep into it at the time. I would love it if you could redo your tests with cake managing the bottleneck link. (we've got a bug in the thing right now at 40+gige, but...) https://arxiv.org/abs/1804.07617 >>> Moreover, if it tends to be unstable on larger scale - what is Google >>> doing then? Thought they've got a more or less homogeneous BBR driven >>> TCP flow ecosystem - at least internally!? Was all propaganda? When >>> speculating, might working for them since of centrally handled flow >>> steering approaches - "imposing inter-flow fairness". >> >> There are certain situations where BBR might work well: >> 1) you only have a single flow at the bottleneck, might be the case in >> their B4 scenario >> 2) The senders a application limited (e.g., YouTube) > > I think the application limited scenario is the primary one. once > typical links are fully capable of video streaming > 4k video a lot of the demand for better congestion control will drop. > >> 3) The bottleneck buffer is much larger than a BDP >> (then BDP will limit the queue size between 1 and 1.5 BDP) > > Sadly we still see 2sec queues on cmtses, in particular. > >> However, BBR has no explicit fairness mechanism, so sometimes >> one will see quite unfair shares for longer periods, >> even if there are only BBR flows present at then bottleneck. > > except with fq at the bottleneck. > >> >> Regards >> Roland >> _______________________________________________ >> Bloat mailing list >> Bloat@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/bloat > > > > -- > > Dave T=C3=A4ht > CEO, TekLibre, LLC > http://www.teklibre.com > Tel: 1-669-226-2619 --=20 Dave T=C3=A4ht CEO, TekLibre, LLC http://www.teklibre.com Tel: 1-669-226-2619