From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-x232.google.com (mail-io0-x232.google.com [IPv6:2607:f8b0:4001:c06::232]) (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 E4DF63BA8E for ; Wed, 29 Aug 2018 04:20:20 -0400 (EDT) Received: by mail-io0-x232.google.com with SMTP id y10-v6so3741755ioa.10 for ; Wed, 29 Aug 2018 01:20:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=OA497rcgDC5gbO/76e9mEDCJA7b6koRUxxUD8MU69dI=; b=fPu+sz+hggUJvDimCAcG9ooRLNkE5PF8unqzCh0ajqkrf7UbvcIIEDxqs5WMXAb9/h x+RZwige8n3LUHwkgFDPCBUVtfaEYCOExHYdywjNMK0+fjwEtGMXZiuUIjbx0rLSlDga Ah2P/Mo0ZM40FHEfALXRr8kEj9jXArTE07m7Fp3FJ8zOATILGggujIZ5YZJQEK4/xWwV YdG/7Aokn9kcCjKAUQzt1lGjezttMlbd5i0IL4LtR0tjim2KAW++dnVZlzyxUYfYUVY2 6hI/f11vk1XYODNFizqFXUu49eoWoHvWjy4xw5oy/QT4ZqFj3vRIxu5HXcPsqQ2KMmdE MmJw== 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=OA497rcgDC5gbO/76e9mEDCJA7b6koRUxxUD8MU69dI=; b=aFV25+u2JqeQti2nFV6DlumfvCZHPTgO4W3NaxUVSjagya0I0z/ISsYPcuPANgC2P5 ygFKyBmBQrnzDxMT45thg56Oox88Pju0DQcOJ40xGrkSkl0CO9H2q+kAFMVbiOvLN5Xc ov300CtQnkYHFD590919/tM53VgWwStuoDKyigJXCvmapGoagDzrtP1Etv7SU3QUFymK KfCINTo57j+/Pgxqsb2i9BL+wMnP03K7cbBPnJ2ZGd1MIQ92hK65DEe3Y/MRdn1FrK0K KLb9+avPoVxN5n33bc4y8MEGcmL7cW7O1/HGDvrpBkS69NyjGNDMIrJWh8KcR+ZE0xMh XhGw== X-Gm-Message-State: APzg51As94q5Sm2XymqwZmP40nVcSZIjLyJXwseMVg9B6+Ron20IDkia R7NiiLlHEmnd+U4lp7Z/atH4GfRjpwWubFqlejc= X-Google-Smtp-Source: ANB0VdbwhqQuijU8edSgUFOHBVNTlbr+lh3GWc1bcfae3oTf4Oq3/rwbUg+WmLlCUT5S+utyTW3BaF7QFfJTgRZJmk0= X-Received: by 2002:a6b:be46:: with SMTP id o67-v6mr4176195iof.143.1535530820346; Wed, 29 Aug 2018 01:20:20 -0700 (PDT) MIME-Version: 1.0 References: <2385fcbb-d460-ce57-e4e3-e3cbb94ebc3d@rogers.com> In-Reply-To: From: =?UTF-8?Q?Jonas_M=C3=A5rtensson?= Date: Wed, 29 Aug 2018 10:20:09 +0200 Message-ID: To: Jonathan Morton Cc: davecb@spamcop.net, bloat Content-Type: multipart/alternative; boundary="00000000000016a78405748ea16b" Subject: Re: [Bloat] an observation from the field 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: Wed, 29 Aug 2018 08:20:21 -0000 --00000000000016a78405748ea16b Content-Type: text/plain; charset="UTF-8" Hi Jonathan, On Wed, Aug 29, 2018 at 2:16 AM Jonathan Morton wrote: > > On 29 Aug, 2018, at 2:53 am, David Collier-Brown > wrote: > > > > Humans experience delays directly, and so perceive systems with high > latency as "slow". The proverbial "man on the Clapham omnibus" therefor > responds to high-latency systems with disgust. > > > > A trained scientist, however, runs the risk of choosing something that > requires complicated measurement schemes, and might well choose to optimize > for throughput, as that sounds like a desirable measure, one matching their > intuitions of what "fast" means. > > The correct approach, for scientists, is to observe that for many > applications, response time (a form of latency) is the *only* relevant > metric. In some cases, higher bandwidth correlates with reduced response > time, such as for software updates. In other cases, bandwidth is > essentially irrelevant, except as it pertains to serialisation delay of > single packets. > Yes, exactly, thank you for bringing some actual scientific reasoning into the discussion. It would actually be nice to have a tool for measuring "response time" for different applications > > Conversely, there are some applications for which sufficient bandwidth is > not a matter of response time, but a threshold prerequisite for correct > operation. We can refer to these as isochronous applications, or choose > another term if you prefer. Video streaming is an example of this; given > an a-priori chosen video codec setting, if the data it produces cannot be > transferred as fast as it is produced, the receiver will not be able to > play it back in synchrony. > > YouTube can reliably stream Full-HD (1080p60) video down a 10Mbps > debloated pipe. The broadband standard in the US claims that 25Mbps is > necessary for this precise application. No, it doesn't. It claims the opposite, i.e. that 10Mbps is sufficient for streaming one HD video but with 25Mbps you can stream two HD videos or one 4K video, see Table 1 in the FCC report: https://docs.fcc.gov/public/attachments/FCC-15-10A1.pdf /Jonas > Draw your own conclusions. > > - Jonathan Morton > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat > --00000000000016a78405748ea16b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi Jonathan,

On Wed, Aug 29, 2018 at 2:16 AM Jonathan= Morton <chromatix99@gmail.com<= /a>> wrote:
&= gt; On 29 Aug, 2018, at 2:53 am, David Collier-Brown <davec-b@rogers.com> wrote:
>
> Humans experience delays directly, and so perceive systems with high l= atency as "slow". The proverbial "man on the Clapham omnibus= " therefor responds to high-latency systems with disgust.
>
> A trained scientist, however, runs the risk of choosing something that= requires complicated measurement schemes, and might well choose to optimiz= e for throughput, as that sounds like a desirable measure, one matching the= ir intuitions of what "fast" means.

The correct approach, for scientists, is to observe that for many applicati= ons, response time (a form of latency) is the *only* relevant metric.=C2=A0= In some cases, higher bandwidth correlates with reduced response time, suc= h as for software updates.=C2=A0 In other cases, bandwidth is essentially i= rrelevant, except as it pertains to serialisation delay of single packets.<= br>

Yes, exactly, thank you for bringing so= me actual scientific reasoning into the discussion. It would actually be ni= ce to have a tool for measuring "response time" for different app= lications
=C2=A0

Conversely, there are some applications for which sufficient bandwidth is n= ot a matter of response time, but a threshold prerequisite for correct oper= ation.=C2=A0 We can refer to these as isochronous applications, or choose a= nother term if you prefer.=C2=A0 Video streaming is an example of this; giv= en an a-priori chosen video codec setting, if the data it produces cannot b= e transferred as fast as it is produced, the receiver will not be able to p= lay it back in synchrony.

YouTube can reliably stream Full-HD (1080p60) video down a 10Mbps debloated= pipe.=C2=A0 The broadband standard in the US claims that 25Mbps is necessa= ry for this precise application.

No, it do= esn't. It claims the opposite, i.e. that 10Mbps is sufficient for strea= ming one HD video but with 25Mbps you can stream two HD videos or one 4K vi= deo, see Table 1 in the FCC report:


/Jonas<= /div>
=C2=A0
Dra= w your own conclusions.

=C2=A0- Jonathan Morton

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