From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oa0-x229.google.com (mail-oa0-x229.google.com [IPv6:2607:f8b0:4003:c02::229]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 63AD021F246; Tue, 29 Apr 2014 10:07:22 -0700 (PDT) Received: by mail-oa0-f41.google.com with SMTP id j17so582292oag.0 for ; Tue, 29 Apr 2014 10:07:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=MJWG9YPI4KE0jWEiRFlvA8qEbbyNpxnFzm/JdfWmay4=; b=RXyTFZRCMuI7YE+2PHLgSJlXnzQQrUaHlynnZVj8YVrLRB7Ukv9LsmwWpOdpePnWDv WfV7ZPKEvpYi9dz2OcSdYIJikPqSsjkgqX3J729W52O1UR8PbZbz7/yy8nG3qHVeWny7 DccU/LlhPevRiIMZgQOnlG8rWMHppRb5ZNsLnB/0YnGCUbd35n9swibxOockpkgt78zr oMUt6kEUKJrwVbI8fLEtwi5OGYTT+JhEGnEbm+HpJ+aAcvH29nx9tA+AqwJ9oUAuuH99 Mj5azPAR3jn+ePj9/BoEUqKERztv8qONX2ONidV+bEJ/MTJnndSNykfuaZI0SqoglKs3 Hz3w== MIME-Version: 1.0 X-Received: by 10.182.38.199 with SMTP id i7mr3013343obk.68.1398791241584; Tue, 29 Apr 2014 10:07:21 -0700 (PDT) Sender: gettysjim@gmail.com Received: by 10.76.73.100 with HTTP; Tue, 29 Apr 2014 10:07:21 -0700 (PDT) In-Reply-To: <87bnvkkr2n.fsf@toke.dk> References: <4130D000-FE28-4A5E-B824-3371C1602472@cisco.com> <87bnvkkr2n.fsf@toke.dk> Date: Tue, 29 Apr 2014 13:07:21 -0400 X-Google-Sender-Auth: LKaC8kagsl7Au9-8GCEVDakmWIY Message-ID: From: Jim Gettys To: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Content-Type: multipart/alternative; boundary=001a11c32ddc11da6c04f83177b6 Cc: bloat , "Fred Baker \(fred\)" , "aqm@ietf.org" , "cerowrt-devel@lists.bufferbloat.net" Subject: Re: [Cerowrt-devel] [aqm] [Bloat] the side effects of 330ms lag in the real world X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 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: Tue, 29 Apr 2014 17:07:22 -0000 --001a11c32ddc11da6c04f83177b6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tue, Apr 29, 2014 at 1:01 PM, Toke H=C3=B8iland-J=C3=B8rgensen wrote: > Jim Gettys writes: > > > Now, if someone gives me real fiber to the home, with a real switch > fabric > > upstream, rather than gpon life might be somewhat better (if the > switches aren't > > themselves overbuffered.... But so far, it isn't. > > As a data point for this, I have fibre to my apartment building and > ethernet into the apartment. I get .5 ms to my upstream gateway and > about 6 ms to Google. Still measured up to ~20 ms of bufferbloat while > running at 100 Mbps... > > http://files.toke.dk/bufferbloat/data/karlstad/cdf_comparison.png > > However, as that graph shows, it is quite possible to completely avoid > bufferbloat by deploying the right shaping=E2=80=8B And in that case fibre > *does* have a significant latency advantage. The best latency I've seen > to the upstream gateway on DSL has been ~12 ms. > =E2=80=8BMedia access is a killer on Cable too, putting the latency floor a= t around 8ms on my Docsis 3.0 Comcast service, though you can sometimes get lucky and piggyback. to somewhat lower latency, IIRC conversations with Greg White about how cable works. - Jim > -Toke > --001a11c32ddc11da6c04f83177b6 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Tue= , Apr 29, 2014 at 1:01 PM, Toke H=C3=B8iland-J=C3=B8rgensen <toke@toke.dk&g= t; wrote:
Jim Gettys <jg@freedesktop.org> writes:

> Now, if someone gives me real fiber to the home, with a real switch fa= bric
> upstream, rather than gpon life might be somewhat better (if the switc= hes aren't
> themselves overbuffered.... But so far, it isn't.

As a data point for this, I have fibre to my apartment building and ethernet into the apartment. I get .5 ms to my upstream gateway and
about 6 ms to Google. Still measured up to ~20 ms of bufferbloat while
running at 100 Mbps...

http://files.toke.dk/bufferbloat/data/karlstad/cdf_com= parison.png

However, as that graph shows, it is quite possible to completely avoid
bufferbloat by deploying the right shaping=E2=80=8B
And in that case fibre
*does* have a significant latency advantage. The best latency I've seen=
to the upstream gateway on DSL has been ~12 ms.

=E2=80=8BMedia a= ccess is a killer on Cable too, putting the latency floor at around 8ms on = my Docsis 3.0 Comcast service, though you can sometimes get lucky and piggy= back. to somewhat lower latency, IIRC conversations with Greg White about h= ow cable works.
=C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0- Jim


-Toke

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