From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua1-x932.google.com (mail-ua1-x932.google.com [IPv6:2607:f8b0:4864:20::932]) (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 D1E333B29E for ; Sat, 25 Apr 2020 23:10:31 -0400 (EDT) Received: by mail-ua1-x932.google.com with SMTP id y10so13725787uao.8 for ; Sat, 25 Apr 2020 20:10:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=q38BUMYx1ypyQyYU9gKDUqfywmxZ7q1IG/zUc/d4kxQ=; b=u0HXJDxCVSYWTmDlOdgIX/GeeBZ5mDxLXPYeBIDQMpRWL4RgDs6OqD/1GgVas781hj AzvQmC6v9nXZcQ2AWq37v/UO40yjCbVF3HJEL2fSGUOwrAbzvko8+xeRTwLCwifGGvVv 6TCM0ln/edB7heBc8q1f9ENMsl1+IDgnUM7P2rlfMzRUHu7x/08kuBRLIEUrg8X3wVAk TvOKKIG55z59Kgw0F+W4ZIz1nTLVyx+fXYol2lc5WtYI2u/Xrg8hnu4yX4rUfsRBERji YxQl5fYnr5h7ez0k5UoeRdYWgnGZep7r8sTGWmnGbek0Pb7Kjm/rRPgCFalctdExQS5/ cgWQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=q38BUMYx1ypyQyYU9gKDUqfywmxZ7q1IG/zUc/d4kxQ=; b=pBzdL7JfvClGgxhXXjpNEC0w6QDReQcisztCFNHrmgzwRN30Gd1TpOwMVCcDGdXuG7 OfbZZl3tIqYGbQURXqKYPtEiYWBs1/M4K5oU/29To+ANz/54roLIL82e68vMAuqTtPgp 8VMBkW2gOwBQdYwXL00xoX13N+WLqA6b3jSN6jdo+m7GvetccSQQjK2LYlKEhxBtkHun IZbUAUcKyzc2/HQa+ikEPkotPngvxRjWfI4ZLFzA4ETM3ZTQS/gpLdqgBzQzG5XzzelG HGFoUjFCbuNkKSKbz4vRl1ACK8XmemyVIlzJ5in1En/JLdXGO1qvpFZZMONgJbp+rVtN VILw== X-Gm-Message-State: AGi0PubKZZTuUheXLBV/YFAvC/hzfOXc7ZKv3FNo2Zk/yqWNjhsTJsS2 zmNrPmL7nQfGzr6uyYwhvwigjGEc8pdPSu6iYP/8tA== X-Google-Smtp-Source: APiQypIeistg14v/Hbm2jtsz4sIzwUI9nZxuTbSmF1BA/i2SbQ3PWAUuZ4gpPlW6ylE5pOAsC2adXI7c5Et6Dc3F2EE= X-Received: by 2002:a67:4242:: with SMTP id p63mr11388169vsa.159.1587870627987; Sat, 25 Apr 2020 20:10:27 -0700 (PDT) MIME-Version: 1.0 References: <85F248E2-E1B5-45A6-8E45-EBCA43B82A09@gmail.com> In-Reply-To: <85F248E2-E1B5-45A6-8E45-EBCA43B82A09@gmail.com> From: Neal Cardwell Date: Sat, 25 Apr 2020 23:10:11 -0400 Message-ID: Subject: Re: [Bloat] dropbox, bbr and ecn packet capture To: Jonathan Morton Cc: Dave Taht , ECN-Sane , bloat Content-Type: multipart/alternative; boundary="000000000000bb859705a428f0f0" X-List-Received-Date: Sun, 26 Apr 2020 03:10:31 -0000 --000000000000bb859705a428f0f0 Content-Type: text/plain; charset="UTF-8" On Sat, Apr 25, 2020 at 8:52 PM Jonathan Morton wrote: > > On 26 Apr, 2020, at 3:36 am, Dave Taht wrote: > > > > I just did a rather large dropbox download. They are well known to be > > using bbr and experimenting with bbrv2. So I fired off a capture > > during a big dropbox download... > > > > It negotiated ecn, my fq_codel shaper and/or my newly ath10k > > fq_codel's wifi exerted CE, osx sent back ecn-echo, and the rtt > > results were lovely. However, there is possibly not a causal > > relationship here, and if anyone is bored and wants to scetrace, > > tcptrace or otherwise tear this cap apart, go for it. > > Well, the CE response at their end is definitely not Multiplicative > Decrease. I haven't dug into it more deeply than that. But they're also > not running AccECN, nor are they "proactively" sending CWR to get a "more > accurate" CE feedback. I suspect they're running BBRv1 in this one. Agreed, that looks like BBRv1. I see a few BBRv1 PROBE_RTT phases in there. Thanks for the trace! best, neal --000000000000bb859705a428f0f0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


=
On Sat, Apr 25, 2020 at 8:52 PM Jonat= han Morton <chromatix99@gmail.c= om> wrote:
dave.taht@gmail.com> wrote:
>
> I just did a rather large dropbox download. They are well known to be<= br> > using bbr and experimenting with bbrv2. So I fired off a capture
> during a big dropbox download...
>
> It negotiated ecn, my fq_codel shaper and/or my newly ath10k
> fq_codel's wifi exerted CE, osx sent back ecn-echo, and the rtt > results were lovely. However, there is possibly not a causal
> relationship here, and if anyone is bored and wants to scetrace,
> tcptrace or otherwise tear this cap apart, go for it.

Well, the CE response at their end is definitely not Multiplicative Decreas= e.=C2=A0 I haven't dug into it more deeply than that.=C2=A0 But they= 9;re also not running AccECN, nor are they "proactively" sending = CWR to get a "more accurate" CE feedback.=C2=A0 I suspect they= 9;re running BBRv1 in this one.

Agreed, tha= t looks like BBRv1. I see a few BBRv1 PROBE_RTT phases in there.
=
Thanks for the trace!

best,
neal

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