From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-xd35.google.com (mail-io1-xd35.google.com [IPv6:2607:f8b0:4864:20::d35]) (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 BF6D03CB61 for ; Sun, 5 Jul 2020 19:06:55 -0400 (EDT) Received: by mail-io1-xd35.google.com with SMTP id c16so37476640ioi.9 for ; Sun, 05 Jul 2020 16:06:55 -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=7GvMtFH7fr50CKDRMO+fx3aH/aaoZqiETLlGrBxjOjU=; b=v/VIhUkTiTvg+4AUIQVqDkK3HdBOaFSbnMeb3YyJgdfkX+AC2TrO5VMOLwZmemh8Lk 6JHq3W5WtZIIKk3iIwbofPGzvy/3nX7Fsk1+C1Q4iBkGwRy+dHXRMfokjx6AzW1CdFPw hNwNYqmSgryu+sGy0itCufr00EgwPvx/hPfeq262S0pOMfEmbxTVQ/kljvhPX6px/oVT wrBqM6UhXhbKsfQW9d0woGXWUzZB4QSGC18OM1+d2EX9rWFgE8N0Kez6LUSH0dTnC2SG DnOJIGkRyZMXJ2UsvnLzm9qyKGu+l7dgzayY61iha8s593IwhD+a4omdK7HqA8VbGoz2 nx7Q== 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=7GvMtFH7fr50CKDRMO+fx3aH/aaoZqiETLlGrBxjOjU=; b=SOeSUCr2vkhylDBoHEVT+Dm+v6AVg7ozZrACt4NWr6fbmeh3BKCEUsmwHyi1Z6t1je uhk2cxg+0jYQthRUTnNvhHvQLrL4KS+m12BU3Yw7tKqt5jSLIT8SZZkYj1HuU4vH9wSY EfTxP5mmrB7fCSr0rOF8O1H/OZwibXv7OTfwV05OUWIQVn494vd2beNDq8EmeVpEeF+a p5bu9PZiQ/GJiQyot8OEV4AmBV1WKgYKZU6tnZqeLCucfbJIuetyOm16OBZOvJXBpvZh xtFO3uuTUxP0SNbbPRMJXMXD5iUmNl1vKscgr1tWSUXNZzo5SOuX1+pbcF/tf5SiIwSn pkWg== X-Gm-Message-State: AOAM530eyaMSIFugrpDKPNbvbfNQmswLIClIdPCaJeTVgSIREKguT7Cy HCUnAwS8ztj0uzxDlWgxjgE17BhvOFB8kEh0qub63Q== X-Google-Smtp-Source: ABdhPJw0w2MMverC9jFaSsMHgYEWAsxCf4OJUi2wd5YZ1s72xxFRZdCia+9sqIrt11eUrCbM6cvaDNgHDi/Fg+o00aM= X-Received: by 2002:a02:5d49:: with SMTP id w70mr51411535jaa.16.1593990415080; Sun, 05 Jul 2020 16:06:55 -0700 (PDT) MIME-Version: 1.0 References: <5405F10B-F446-4B74-8894-33232145EB2E@gmx.de> <9A7FBFF1-7F10-41DD-B5C3-5A45254CEB54@gmx.de> <14692.1593971007@localhost> <20200705110934.55bcfb43@hermes.lan> In-Reply-To: From: Matt Mathis Date: Sun, 5 Jul 2020 16:06:42 -0700 Message-ID: Subject: Re: [Bloat] the future belongs to pacing To: Jonathan Morton Cc: Stephen Hemminger , Make-Wifi-fast , Carlo Augusto Grazia , bloat , Jamshid Mahdavi Content-Type: multipart/alternative; boundary="00000000000077d9cf05a9b9d0b3" X-Mailman-Approved-At: Mon, 06 Jul 2020 06:38:11 -0400 X-List-Received-Date: Sun, 05 Jul 2020 23:06:55 -0000 --00000000000077d9cf05a9b9d0b3 Content-Type: text/plain; charset="UTF-8" What the complexity buys you is that BBRs metrics max_BW, min_RTT, and the ACK aggregation/batching metrics are actual parameters of the network, and observable with passive instrumentation of the packet streams. Traditional CC is a collection of heuristics to estimate cwnd, which has a clear interpretation in terms of action (when to send), but the optimal cwnd can't easily be observed from the packet stream. I think this alone will have impact, in terms of being able to reason about CC behaviors. Thanks, --MM-- The best way to predict the future is to create it. - Alan Kay We must not tolerate intolerance; however our response must be carefully measured: too strong would be hypocritical and risks spiraling out of control; too weak risks being mistaken for tacit approval. On Sun, Jul 5, 2020 at 11:13 AM Jonathan Morton wrote: > > On 5 Jul, 2020, at 9:09 pm, Stephen Hemminger < > stephen@networkplumber.org> wrote: > > > > I keep wondering how BBR will respond to intermediaries that aggregate > packets. > > At higher speeds, won't packet trains happen and would it not get > confused > > by this? Or is its measurement interval long enough that it doesn't > matter. > > Up-thread, there was mention of patches related to wifi. Aggregation is > precisely one of the things that would address. I should note that the > brief description I gave glossed over a lot of fine details of BBR's > implementation, which include careful filtering and conditioning of the > data it gathers about the network path. > > I'm not altogether a fan of such complexity. > > - Jonathan Morton > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat > --00000000000077d9cf05a9b9d0b3 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
What the complexity buys you is that BBRs metrics max_BW, = min_RTT, and the ACK aggregation/batching metrics are actual parameters of = the network, and observable with passive=C2=A0instrumentation of the packet= streams.=C2=A0 Traditional CC is a collection of heuristics to estimate cw= nd, which=C2=A0has a clear interpretation=C2=A0in terms of action (when to = send), but the optimal cwnd can't easily be observed from the packet st= ream.

I think this alone will have impact, in terms of b= eing=C2=A0able to reason about CC behaviors.

Thank= s,
--MM--
The best way to predict the future is to create it. =C2= =A0- Alan Kay

We must not tolerate intolerance;
=C2=A0 =C2=A0 =C2=A0 =C2=A0however our response must be carefully measure= d:=C2=A0
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 too strong wou= ld be hypocritical and risks spiraling out of control;
=C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 too weak risks being mistaken for tacit app= roval.


<= div class=3D"gmail_quote">
On Sun, Jul= 5, 2020 at 11:13 AM Jonathan Morton <chromatix99@gmail.com> wrote:
> On 5 Jul, 2020, at 9:09 pm, Stephen Hemmin= ger <ste= phen@networkplumber.org> wrote:
>
> I keep wondering how BBR will respond to intermediaries that aggregate= packets.
> At higher speeds, won't packet trains happen and would it not get = confused
> by this? Or is its measurement interval long enough that it doesn'= t matter.

Up-thread, there was mention of patches related to wifi.=C2=A0 Aggregation = is precisely one of the things that would address.=C2=A0 I should note that= the brief description I gave glossed over a lot of fine details of BBR'= ;s implementation, which include careful filtering and conditioning of the = data it gathers about the network path.

I'm not altogether a fan of such complexity.

=C2=A0- Jonathan Morton

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