From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x232.google.com (mail-qt0-x232.google.com [IPv6:2607:f8b0:400d:c0d::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 347253CB35 for ; Tue, 28 Aug 2018 00:44:24 -0400 (EDT) Received: by mail-qt0-x232.google.com with SMTP id t39-v6so295619qtc.8 for ; Mon, 27 Aug 2018 21:44:24 -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:content-transfer-encoding; bh=HPmu9OVZOtIURcJHYC2lofZjxB++/F3EtVC0UBRqr04=; b=jsW1ZBace6QqwtwQXhDTsP2kJR+3SVDyEno1HT1rShNz43JoS8BILI9pzKYlQnVxiI lxQZkF1mHBPHur8GioocDtGeY4soNWKw32vrhg9JCjCM3mtJstYH7F1z86QO8J6Ed+Vx q+B5JADsh5FS90aYnLf1H6okpRNs+Fa2dzYZsPQvyGTbElz8dLVAlgIAGgF49o4iAu+E jcenvWMnZ/zYCbYFIzoNFEXBzNoUQF8CMATGoDPFFYf78nrO1ryXXeh+Gd4uUEY+U2pT jco3wkgVb6zC2l7eR4He5HNpUli7Qod0fdM61NGjB0ze/nzgidHBmgjDiu/SDK4IfCOe pwJA== 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:content-transfer-encoding; bh=HPmu9OVZOtIURcJHYC2lofZjxB++/F3EtVC0UBRqr04=; b=jl2Ilk/yLUbnJiWL+lFfo9eqHd9S+C5UG6poEXc1PgPzlXOLChFofk+kUz+FkcaXU0 XlZ2rHPiPsvmsqInQUDSaBp/h1YBKdWHmOuLWI22bmuhuEmzDluz8gSa7wYbSaUp5AI7 PDeEuntXG2sNQLcFFaAtL9SvwxMRkix76rj+fR64AIUOPCQLXWoIxh271ftIv6gL2ZU3 y2rVr4OWA860ZvqgSDkVOm42HT7zSAd2qrhh2d/XhxzrkgmYbHg4M5XbY1eJFRAGyWhV P+ER7/8XSzAMmh8G7L9i1Clmn1SFeXRmvDG5tvlO6HZGEpc8GtCyo6u2gF3/xio2Mnjv /GtA== X-Gm-Message-State: APzg51DQ3MUH7xl0BpeL8dhsgZnwLvh5CmP3oJFOGJMtYsyYW4UwmHbs fgId7P9tbnKKdeP7U/cpn3c9JvyS88oMoGEu57k= X-Google-Smtp-Source: ANB0VdaQVeF4ubNEogD4WYAZgUlkjOX6YuDbwAH8nqU21umm3vIjvlnDUerKBmu3iW/QB7rNP9ZpCrXSqLsmq7gY+lY= X-Received: by 2002:ac8:3388:: with SMTP id c8-v6mr17476745qtb.238.1535431463680; Mon, 27 Aug 2018 21:44:23 -0700 (PDT) MIME-Version: 1.0 References: <1535286372.35121837@apps.rackspace.com> <2282D31E-CBEF-4B42-A6A6-4D6394EE0DF7@gmail.com> In-Reply-To: From: Dave Taht Date: Mon, 27 Aug 2018 21:44:11 -0700 Message-ID: To: David Lang Cc: Bob McMahon , Make-Wifi-fast Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Make-wifi-fast] deep wifi 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: Tue, 28 Aug 2018 04:44:24 -0000 On Mon, Aug 27, 2018 at 8:32 PM David Lang wrote: > > Think of the DoS possibilities if you can tell other networks to not tran= smit. Actually, that's a thing. google for "ap suppression". > David Lang > > > > On Mon, Aug 27, 2018 at 6:56 PM Bob McMahon = wrote: > >> > >> Hmm, not sure I understand the distinction. CTS per the AP informs t= hose other transmitters to stay quiet per the CTS NAV. I may be misunderst= anding things. Thanks for the continued discussions. It helps to better t= horoughly understand the issues. > >> > >> Bob > >> > >> On Mon, Aug 27, 2018, 6:52 PM David Lang wrote: > >>> > >>> On Mon, 27 Aug 2018, Bob McMahon wrote: > >>> > >>>> I thought that RTS/CTS would handle the case of hidden nodes, i.e. a= device > >>>> that fails to successfully transmit can resort to RTS/CTS to get the > >>>> receiver to reserve time for it. Also, lack of a RX ack seems ok to > >>>> trigger MAC level retransmits. > >>> > >>> the problem isn't getting the receiver to reserve time for it, it's g= etting the > >>> other transmitter(s) to not step on it when it transmits. Those other > >>> transmitters may belong to different people, sharing a channel with y= our system > >>> and nothing else. > >>> > >>> David Lang > >>> > >>>> It seems the LBT bug is the collision avoidance overheads when it is= n't > >>>> needed, i.e. no other energy would cause the RX PHY to fail its deco= de and > >>>> the EDCA backoffs had no benefit, stochastic or otherwise. Optimiz= ing > >>>> that out is said to be not possible from local information only and = per > >>>> "shared" spectrum. > >>>> > >>>> Bob > >>>> > >>>> > >>>> On Mon, Aug 27, 2018 at 3:33 PM David Lang wrote: > >>>> > >>>>> On Mon, 27 Aug 2018, Jonathan Morton wrote: > >>>>> > >>>>>> So in practice, it's easier to measure SNR at the receiver, or > >>>>> indirectly by > >>>>>> observing packet loss by dint of missing acknowledgements returned= to > >>>>> the > >>>>>> transmitter. > >>>>> > >>>>> Also, there may be other transmitters that the recipient of the pac= kets > >>>>> can hear > >>>>> that you cannot hear, so it's not possible to detect colliding > >>>>> transmissions > >>>>> directly in all cases. > >>>>> > >>>>> This is another trap that digital/wired people fall into that doesn= 't > >>>>> really > >>>>> apply in the analog/radio world. > >>>>> > >>>>> David Lang > >>>>> > >>>> > >> > >> _______________________________________________ > >> Make-wifi-fast mailing list > >> Make-wifi-fast@lists.bufferbloat.net > >> https://lists.bufferbloat.net/listinfo/make-wifi-fast > > > > > > > > --=20 Dave T=C3=A4ht CEO, TekLibre, LLC http://www.teklibre.com Tel: 1-669-226-2619