From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <toke@toke.dk>
Received: from mail.toke.dk (mail.toke.dk [52.28.52.200])
 (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits))
 (No client certificate requested)
 by lists.bufferbloat.net (Postfix) with ESMTPS id 697803B29E;
 Fri,  1 Dec 2017 08:40:46 -0500 (EST)
From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023;
 t=1512135643; bh=YwN+o6GKHUkx9Kj/gwfUM/Q02oAYN1Y1sdEzzyNTmXk=;
 h=From:To:Cc:Subject:In-Reply-To:References:Date:From;
 b=IL8A0lOXVAm34SHbAMtGBbtUcJAoGgHfohtjQczOciPUbf2aadMHvWylZkGjVGx39
 dUbVPG7xcsM1eQCSa3ei8Xy7sf9mhcEWpyDL/RzRn21nYgZ49svnB3TmLY+BdiuBPV
 XAhFQ1HFsx2QjRfJ8NjpH9XmnTjwfXBZdkG0L+53LIbBv+i5ov53YXsfhVKbFJx6/d
 vjLRRYqqqBti+WNVBKxnpeXz4vfF68eZAY8Ih9M/Nvr00jukKQcoSNLVHp6hO3lsdE
 f/jPueELsMlKS0ejiIJqhE+Ds1FJvhkFr/FT/Qhz/RqNJSIgWdvkreSX0W/xAQvpGj
 2sfGjBZkq4WVQ==
To: Luca Muscariello <luca.muscariello@gmail.com>
Cc: Jan Ceuleers <jan.ceuleers@gmail.com>, bloat <bloat@lists.bufferbloat.net>,
 make-wifi-fast@lists.bufferbloat.net
In-Reply-To: <CAHx=1M4SXef8KSqQ1YaduKYFG5A4eJJxSUKGjNArGKZSwLG7Hw@mail.gmail.com>
References: <CAA93jw47ZAXAJmiOVCb2NR3JRcCfmX0TLr+55O0G+J6HCW5bVQ@mail.gmail.com>
 <alpine.DEB.2.20.1711290655590.32099@uplift.swm.pp.se>
 <4D0E907C-E15D-437C-B6F7-FF348346D615@gmx.de>
 <alpine.DEB.2.20.1711291347050.32099@uplift.swm.pp.se>
 <CAHx=1M7=ig-S-iQ_Fj2f-KMoa-QUVu1DZ4HyfWybvQiGeBb1GQ@mail.gmail.com>
 <alpine.DEB.2.20.1711291528260.32099@uplift.swm.pp.se>
 <CAHx=1M77XYX9t6J_zG1oArOze1-nTRPB9bNQLRfwFRZjH3mQjQ@mail.gmail.com>
 <7B92DF4D-B6B5-4A64-9E10-119DCA2D4A6F@ifi.uio.no>
 <CAJq5cE36bErJGDQQutpFgbENmiN9SvSc+bVXJ-BmZ9S_Jv3joA@mail.gmail.com>
 <1512037480.19682.10.camel@gmail.com>
 <alpine.DEB.2.20.1711301343320.32099@uplift.swm.pp.se>
 <alpine.DEB.2.02.1711301623270.2950@nftneq.ynat.uz>
 <6b494910-1373-afb0-5b93-99b725391fb3@gmail.com> <87wp2638yo.fsf@toke.dk>
 <CAHx=1M4SXef8KSqQ1YaduKYFG5A4eJJxSUKGjNArGKZSwLG7Hw@mail.gmail.com>
Date: Fri, 01 Dec 2017 14:40:40 +0100
X-Clacks-Overhead: GNU Terry Pratchett
Message-ID: <87tvxa36sn.fsf@toke.dk>
MIME-Version: 1.0
Content-Type: text/plain
Subject: Re: [Make-wifi-fast] [Bloat] benefits of ack filtering
X-BeenThere: make-wifi-fast@lists.bufferbloat.net
X-Mailman-Version: 2.1.20
Precedence: list
List-Id: <make-wifi-fast.lists.bufferbloat.net>
List-Unsubscribe: <https://lists.bufferbloat.net/options/make-wifi-fast>,
 <mailto:make-wifi-fast-request@lists.bufferbloat.net?subject=unsubscribe>
List-Archive: <https://lists.bufferbloat.net/pipermail/make-wifi-fast>
List-Post: <mailto:make-wifi-fast@lists.bufferbloat.net>
List-Help: <mailto:make-wifi-fast-request@lists.bufferbloat.net?subject=help>
List-Subscribe: <https://lists.bufferbloat.net/listinfo/make-wifi-fast>,
 <mailto:make-wifi-fast-request@lists.bufferbloat.net?subject=subscribe>
X-List-Received-Date: Fri, 01 Dec 2017 13:40:46 -0000

Luca Muscariello <luca.muscariello@gmail.com> writes:

> If I understand the text right, FastACK runs in the AP and generates an ACK
> on behalf (or despite) of the TCP client end.
> Then, it decimates dupACKs.
>
> This means that there is a stateful connection tracker in the AP. Not so
> simple.
> It's almost, not entirely though, a TCP proxy doing Split TCP.

Yeah, it's very much stateful, and tied closely to both TCP and the MAC
layer. So it has all the usual middlebox issues as far as that is
concerned... Also, APs need to transfer state between each other when
the client roams.

It does increase single-flow TCP throughput by up to a factor of two,
though... Which everyone knows is the most important benchmark number ;)

-Toke