From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-il1-x131.google.com (mail-il1-x131.google.com [IPv6:2607:f8b0:4864:20::131]) (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 D63793B29D for ; Thu, 23 Jul 2020 08:56:00 -0400 (EDT) Received: by mail-il1-x131.google.com with SMTP id p15so4165797ilh.13 for ; Thu, 23 Jul 2020 05:56:00 -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 :content-transfer-encoding; bh=DSIeaxlMB1OOd7gpu8BhZ3YDwxIQ1/Hj+h+s+iWV9Ho=; b=FtTqAAi61XJLlNpCYX2O/3/sK7t6Jm/ColHVHOH6Jn5OpPmze4HKJEVwrH5nlLbdYl WgvSR2cK6FRPmfKSjujgXiQVpm57YR2Xfeiplmnq+/TC9VgQR2R9Xyl1UrGozRUZCzvd RECzWlvJ84p7iu0nrwm0ZYLD5OX5ZJ30zlidC8/Fwdt6WVkDqqt3vAPPms94IFfi66Hi yfPWAv7S7PmauUkVJqQ0naZ/Ydx6d76zhN+Eg4HoOVLNaCSamojg8ovWs3ohiPbL++Iz My5p8HBVlrN5oqNufwbJynzGJiHCY7lo+szCwkgGyxQvjEXJlduYfiNpc9D03jRqUg6N bBxA== 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:content-transfer-encoding; bh=DSIeaxlMB1OOd7gpu8BhZ3YDwxIQ1/Hj+h+s+iWV9Ho=; b=BVX64uqjO3Jz5NHEUpqTPB2oU2H4m9phuI1tvxwPMW6y2Ai1j9SopHgE6qxQSaAOMu n7KXIys65W1Sbkc5vIOhZZpkvLo7lIN2v3+dpMlt44PnGj7/AfmB/l4kOwo9lyGDAt3Y d7O3s7pUnakHY5wGtC7wyCOhgHBS/a0ifxnCDk0p5ZrO4CEMovpNVinpP+stTHDQx+2T u4MOb5IbWY/32Wowu8Ko0XQIPDuLfzn0cbyKijxBSTsYuHW+PnlUNjF4ixGC6Is/CyHS 0lVZ+nFWuxf86VfoyYTJWsh1yyXBxnkxi4oC/dXph91f0qxikrS+kqeGbuWmWVYSHopN 4Vbg== X-Gm-Message-State: AOAM532ibJKyScs4aeEzOj6yVX36HEI3CkuT6F3W9hmcKgkmzOBhpT7x j83lYIC8coEekKLSC33yFTnPI7dv1fnPX/uQHyiBgg== X-Google-Smtp-Source: ABdhPJwa7P0p8YztpoRiGZnQJBJSuhMACpoBHYnWoULQ0HVY7fyM5wg46hDpEUijc4OkBUXcSdRbs7SvC3nYsJMUlGo= X-Received: by 2002:a92:d64d:: with SMTP id x13mr4823198ilp.287.1595508959985; Thu, 23 Jul 2020 05:55:59 -0700 (PDT) MIME-Version: 1.0 References: <8641.1595508570@hop.toad.com> In-Reply-To: <8641.1595508570@hop.toad.com> From: Dave Taht Date: Thu, 23 Jul 2020 05:55:48 -0700 Message-ID: To: Make-Wifi-fast Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: [Make-wifi-fast] Fwd: "Why Wi-Fi Stinks -- and How to Fix It" (DFS support) 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: Thu, 23 Jul 2020 12:56:00 -0000 ---------- Forwarded message --------- From: John Gilmore Date: Thu, Jul 23, 2020 at 5:49 AM Subject: "Why Wi-Fi Stinks -- and How to Fix It" (DFS support) To: Dave Taht , [fixed for easy forwarding.] https://spectrum.ieee.org/telecom/wireless/why-wifi-stinksand-how-to-fix-it https://portalwifi.com/technology This guy, Terry Ngo, founder of Ignition Design Labs, was trying to do Dynamic Frequency Selection (DFS) for WiFi, to triple the amount of 5 GHz WiFi bandwidth available in places that aren't using those frequencies for fixed radars. Early access points that used these frequencies caused a lot of interference, so governments revised the rules and now access points have to scan the band for radars for a significant period of time before transmitting on them (and scoot away if they hear a radar later). But if they see no radar, they get access to a much less congested set of frequencies, adding TWICE the total bandwidth of all the unrestricted WiFi frequencies. Seems like you and Mr. Ngo have complementary efforts to Make WiFi Fast. Are you in touch? You should ideally coordinate. You both are engaged in trying to get vendors to adopt new tech that makes wifi better; you can probably trade contacts and find some interesting opportunities. As one example, he was building (and trying to license out designs for) access points that rapidly and constantly monitor spectrum so they can immediately switch to a channel that's free of radars (without waiting 30 seconds to scan it for radar interference). Part of their design reports usage & interference to a "cloud" server, which is then shared with other access points (and gets fed back into their engineering effort). Perhaps free Linux code could do similar things but just do it locally, avoiding the cloud. Possibly share it locally, if there's any reason to do so, either over Ethernet multicasts, or through WiFi spectrum. Then you could get the benefits in any wifi LAN, whether or not it foolishly allows random infrastructural equipment to phone home to server farms. I recently bought one of the "Portal Wifi" access points that they shipped for a while (it looks like their company is out of business, there's no support website any more, there's one guy answering support tickets on Twitter as of last month, but the hardware is still available from a sales channel and is down to $50 on Amazon). Scrounging around on the Wayback Machine for their "open source" legal page, it is based on openwrt-release-15.05. When I plug it in, it does succeed in finding a channel in the DFS frequencies, that's free of local radars at my location, which is what they claimed as their main innovation. The access point lives on that channel, and user nodes are legally able to use those frequencies when they are connected to an access point there. I didn't find good web resources about how widespread the hardware support for using the DFS frequencies is, in current commercially available hardware (and in free software that drives it). Does somebody on the list know? Is it standard in every AP now? Or only in specialized ones like the Portal? Here are more resources on DFS. Here's a great conference presentation with a history of DFS and the problem it solves: https://mum.mikrotik.com//presentations/UK16/presentation_3845_1479299009= .pdf The bandplan, at least for the US: https://apps.fcc.gov/kdb/GetAttachment.html?id=3D1K3EcgPRatUcWMwkA%2BuROw= %3D%3D&desc=3D905462%20D06%20802%2011%20Channel%20Plans%20%20New%20Rules%20= v02&tracking_number=3D27155 (the whole portion between 5250 MHz and 5725 MHz requires DFS) There's a Wikipedia page that works hard to summarize the global regulatory structure around these frequencies: https://en.wikipedia.org/wiki/List_of_WLAN_channels Here's some early Linux WiFi work on DFS: https://wireless.wiki.kernel.org/en/developers/dfs (this looks like it's 10 years old -- anybody want to update it?) John --=20 "For a successful technology, reality must take precedence over public relations, for Mother Nature cannot be fooled" - Richard Feynman dave@taht.net CTO, TekLibre, LLC Tel: 1-831-435-0729