From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ej1-x634.google.com (mail-ej1-x634.google.com [IPv6:2a00:1450:4864:20::634]) (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 28E4C3B29E for ; Wed, 7 Jul 2021 15:10:13 -0400 (EDT) Received: by mail-ej1-x634.google.com with SMTP id gb6so5012145ejc.5 for ; Wed, 07 Jul 2021 12:10:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=+Bn6aMWldNRcJHqPEOorN4AVoDpMDHOOisrAkjsiVXc=; b=OoIlHbetj26xU3ByMuVOvehHwAsChQtx5N4EloVbejqVJOuqZMFPo4OUSlzQTje+yD dWz4NYaUgO8QxSuM/7u6fW6rHGEPPfr/61P7KW8SLlWXs8oXwfM5CiPCCDz32UzCrffs vYDf92jl0cEZKKl1OWOtHNhJ9qR/r3J0KMKAs= 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=+Bn6aMWldNRcJHqPEOorN4AVoDpMDHOOisrAkjsiVXc=; b=EWr8PXh8FF5WpjBhSv3GkhZVoOeJT3xfV0bjl3LKANiB4UONGXfKUrBq/rAy+C/Oce 01U2TvnZgdIDgTeWe/12oPoW7ib7cfzVrwsbFB2kQ87mjM4n/9urvHVZ3guIukzOAjaP 1caritZVWjXgY5zbLyjo0tlWSxNG5PLE8sWJ84QgffXgCJWBafEm40DJKONKK29eOh+J p0xvxeA9PU38KvW59Poz3NqQ/nnB5wxL+wSORvqfs3Nv/dyVVTTDJoeow5r7U2VvQVe1 YCqTcPWRyA7XPDhE7cDiksNAeVMs1U+YYrHUJwx52FhivEC6JK1ddZVGKAKPSDdJMOiI Y0Sw== X-Gm-Message-State: AOAM532nEfj7A5OdAAbq9n6HZseDfp8sW5tafALVzg4EjSp/hQk4bjpY ao0JqCUvbwZb6gZ0Fg25Ft8s/tquSYxPgU5e1tLOgYuRy+WQCBzL5khm2UBxuTmwYFxgYaqIvVe 4klbLiVT6s/FxQUZs5S+q7RhsJ42HMKVB5KMCnFWeM/zusVPeSw== X-Google-Smtp-Source: ABdhPJy+Ri3mBi7uAMAQ3g+OUvJ9+kulRUnVdEvcK0XC6yMYgco59c93EwfTW/VA9SbRDp4rwOaRh0n0PZkXMoCZtLo= X-Received: by 2002:a17:906:1da1:: with SMTP id u1mr25521830ejh.307.1625685011648; Wed, 07 Jul 2021 12:10:11 -0700 (PDT) MIME-Version: 1.0 References: <303da319-87dd-46c0-928f-cad7f93835f8n@googlegroups.com> <39791d24-1b6b-98bf-c870-4c52d7952cd2@wizmail.org> In-Reply-To: <39791d24-1b6b-98bf-c870-4c52d7952cd2@wizmail.org> From: Bob McMahon Date: Wed, 7 Jul 2021 12:10:00 -0700 Message-ID: To: Jeremy Harris Cc: Make-Wifi-fast Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="000000000000a9944005c68d494e" Subject: Re: [Make-wifi-fast] Fwd: [bbr-dev] BBR performance and optimization in cellular wireless network with high delay jitter X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 Jul 2021 19:10:13 -0000 --000000000000a9944005c68d494e Content-Type: multipart/alternative; boundary="000000000000a338c105c68d4922" --000000000000a338c105c68d4922 Content-Type: text/plain; charset="UTF-8" I'm wondering if the whole idea that throughput as the exclusive vector for optimization is a bit off. Even low latency high throughput designs has throughput as a driving vector. We now have high occupancy low latency (HULL) data center switches. We have to oversubscribe everything (and TCP is more than happy to oblige.) As a group, we all do this because of exactly why? It reminds me of "weight" in the space program. Weight drove most every decision due the energy cost required to get mass out of the influence of earth's gravity. Structural integrity be damned - just make sure it has less mass. An app setting TCP_NODELAY on a socket could signal the end to end path that the thing to optimize for this flow is latency, i.e. that the app writing this socket isn't going to be sending lots of data. In this case, the TCP feedback loop could adjust its vectors as an example. And TCP has little clue of what the app is going to do, though it can guess at it (and can guess wrong.) I think WiFi/wireless (or no cables to act as wave guides) makes the problem quite challenging for lots of reasons. I also think the silo'ing of engineering both within companies and between companies adds to these engineering limitations. What is the OSI layer but a human abstraction? Why can't TCP be informed about PHY related things, and MACs be aware about TCP related things? I here the call of blasphemy, "It must be end knowledge only!!" Even the TCP assumption that a dropped packet is due to congestion is flawed. It might be due to walking past a microwave that is irradiating a bag of popcorn. Or the device orientation may change just enough that a new spatial stream is now available, instantly doubling capacity. Or more radios can be used as CMOS radios are trending to abundance. Just thinking out loud a bit. Sorry for the meandering in thoughts, Bob On Wed, Jul 7, 2021 at 1:27 AM Jeremy Harris wrote: > On 07/07/2021 00:49, Bob McMahon via Make-wifi-fast wrote: > > ABC (love the acronym) > > Conflict with Approrriate Byte Counting, though. > > > Does ABC try to > > optimize throughput, latency or some combination, e.g. network power > > (throughput/delay)? > > I read it as trying to optimize throughput of one specific link > (the one next to the detecting location). They didn't discuss > what happens when there are two such on the path, and most of the > presentation assumed that this link was the limiting one. > -- > Cheers, > Jeremy > _______________________________________________ > Make-wifi-fast mailing list > Make-wifi-fast@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/make-wifi-fast -- This electronic communication and the information and any files transmitted with it, or attached to it, are confidential and are intended solely for the use of the individual or entity to whom it is addressed and may contain information that is confidential, legally privileged, protected by privacy laws, or otherwise restricted from disclosure to anyone else. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, you are hereby notified that any use, copying, distributing, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited. If you received this e-mail in error, please return the e-mail to the sender, delete it from your computer, and destroy any printed copy of it. --000000000000a338c105c68d4922 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I'm wondering if the whole idea that throughput as the= exclusive vector for optimization is a bit off. Even low latency high thro= ughput designs has throughput as a driving vector. We now have high occupan= cy low latency (HULL) data center switches. We have to oversubscribe everyt= hing (and TCP is more than happy to oblige.) As a group, we all do this bec= ause=C2=A0of exactly why?=C2=A0

It reminds me of "weight" = in the space=C2=A0program. Weight drove most every decision due the energy = cost required to get mass out of the influence of earth's gravity. Stru= ctural integrity be damned - just make sure it has less mass.

An app= setting TCP_NODELAY on a socket could signal the end to end path that the = thing to optimize for this flow is latency, i.e. that the app writing this = socket isn't going to be sending lots of data. In this case, the TCP fe= edback loop could adjust its vectors as an example. And TCP has little clue= of what=C2=A0the app is going to do, though it can guess at it (and can gu= ess wrong.)

I think WiFi/wireless (or no cables to act as wave guide= s) makes the problem quite challenging for lots of reasons. I also think th= e silo'ing of engineering both within companies and between companies a= dds to these engineering limitations. What is the OSI layer but a human abs= traction? Why can't TCP be informed about PHY related things, and MACs = be aware about TCP related things?=C2=A0 I here the call of blasphemy, &quo= t;It must be end knowledge only!!"

Even the TCP assumption that= a dropped packet is due to congestion is flawed. It might be due to walkin= g past a microwave that is irradiating a bag of popcorn. Or the device orie= ntation may change just enough that a new spatial stream is now available, = instantly doubling capacity.=C2=A0 Or more radios can be used as CMOS radio= s are trending to abundance.=C2=A0

Just thinking out loud a bit. Sor= ry for the meandering in thoughts,
Bob






=
On Wed, Ju= l 7, 2021 at 1:27 AM Jeremy Harris <j= gh@wizmail.org> wrote:
On 07/07/2021 00:49, Bob McMahon via Make-wifi-fast wrote: >=C2=A0 ABC (love the acronym)

Conflict with Approrriate Byte Counting, though.

> Does ABC try to
> optimize throughput, latency or some combination, e.g. network power > (throughput/delay)?

I read it as trying to optimize throughput of one specific link
(the one next to the detecting location).=C2=A0 They didn't discuss
what happens when there are two such on the path, and most of the
presentation assumed that this link was the limiting one.
--
Cheers,
=C2=A0 =C2=A0Jeremy
_______________________________________________
Make-wifi-fast mailing list
M= ake-wifi-fast@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/make-wif= i-fast

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