From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x233.google.com (mail-wm0-x233.google.com [IPv6:2a00:1450:400c:c09::233]) (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 D7FA03B29E for ; Sun, 26 Nov 2017 05:53:07 -0500 (EST) Received: by mail-wm0-x233.google.com with SMTP id v186so29504002wma.2 for ; Sun, 26 Nov 2017 02:53:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=8b1B+7w7BIG33ejFl7iNECeEBSw2EdV5MROHrhM8+54=; b=E6UArhlkyjuy4YazJ8Y7D2lpJ53zsRJTp8m9ai4PcyR+xZxM3hj6R+B1DPz1d9UTg8 KhuZbiy6N2M1NSGESyrDMJrUelx+WcWXbCHfzu5zE3GTGUjCA4osS8CD2Kq5kM6lxdG7 cl2Fzo6VM17ZaCMYhC9zSWq82iVhT1Eu1H1tX4w9bm9heFAvb2C/HZxgXtsEvOAe9R7p 1nLhCNrxzRcoiwGc+DBQcCOQ1ocdC/RGT9E+6jn5fPWSVXSqSV+rQ4vomOZ1C5AycAXt MNn0pgDpU7wV+JAlos2/wqx39r+m6GS8M1Vhg0QDOcKTGC9hYtHxtBDFb7QThRjd4YZ1 gDWQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=8b1B+7w7BIG33ejFl7iNECeEBSw2EdV5MROHrhM8+54=; b=RqjArsuDj9TeJWF+wECtEbAIAlJv7MiyG5nVOHz9hOFtXtAtWX+yODSgcW6vcKkHeG EPCROOYB1Dp//6zjqeIe9Rd3BnBlEUcuNoIxDvkyr5yK1OW17U0YKsBAilXGLFKB+Z0+ wqyl0P9ZTDsjBQg1HCi5QChBmFkAw4d2ImQDSH26YZTWlVwZqZayKJKYLzbAvE+T6oD/ iJ/P7V5MLLDLbc6g16guNfgS4P/QjE3N+aMV5nAfuAuXr1KQdfungXRr2Oj3li0OpBSA XYdrBXEcqA6S9KzNwkCmPbZYrrFUbZ32e1eSBrVKTv7H84v8rLSZ8umZZ01JckyHhQCZ WN8Q== X-Gm-Message-State: AJaThX6PAF6v7BbSq0HoH3Sd9F2cj0/QQgGSWA3dh6fzj4Wd6ThzzaDy DumgjCVXA7RO7jHNv4aBNuU= X-Google-Smtp-Source: AGs4zMaDwK+ZkBwhGF/V8y2gPhxHzEfLsQpi+few7pVCmyr6HG616X/GlTrZijtpehndORJTBAfmPg== X-Received: by 10.80.172.29 with SMTP id v29mr47748468edc.143.1511693586712; Sun, 26 Nov 2017 02:53:06 -0800 (PST) Received: from zotac.xperim.be (22.49-200-80.adsl-dyn.isp.belgacom.be. [80.200.49.22]) by smtp.gmail.com with ESMTPSA id 26sm6379585eds.67.2017.11.26.02.53.06 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 26 Nov 2017 02:53:06 -0800 (PST) Received: from [192.168.8.172] (unknown [192.168.8.172]) by zotac.xperim.be (Postfix) with ESMTPSA id 02D0A4813D4; Sun, 26 Nov 2017 11:53:05 +0100 (CET) To: Jonathan Morton Cc: bloat References: <20171124092021.DC01D40605C@ip-64-139-1-69.sjc.megapath.net> <4a37c330-cb03-23eb-f705-743c6cb30c15@gmail.com> From: Jan Ceuleers Message-ID: Date: Sun, 26 Nov 2017 11:53:04 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Subject: Re: [Bloat] Steam In Home Streaming on ath9k wifi X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 26 Nov 2017 10:53:08 -0000 On 26/11/17 11:05, Jonathan Morton wrote: > Another explanation for latency spikes on the order of 100ms is that a > periodic (and wholly unnecessary) scan for other APs is run, which > requires the wifi radio to be temporarily tuned away from the currently > associated AP's frequency. My understanding is that APs that operate on channels that are wider than 20MHz must back off to 20MHz in case they detect other SSIDs that are competing for the wider channel. So this is clearly "unnecessary" from the point of view of the AP itself, but it does make the AP a better citizen to be aware of who else is trying to access the medium.