From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x533.google.com (mail-ed1-x533.google.com [IPv6:2a00:1450:4864:20::533]) (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 75C493B29E for ; Thu, 2 Dec 2021 03:11:38 -0500 (EST) Received: by mail-ed1-x533.google.com with SMTP id r25so46627951edq.7 for ; Thu, 02 Dec 2021 00:11:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=2noV03mEG2xilINOY7bIYeJq2mnGIWLLyr24P0XEP9A=; b=JKGO1xtpTfotECHs9E6ybbcFwtUFKSq3StweMtuY6kSdaYnlpcknORLaNJM3BHNYrM eGv6oawO/n00WdC2OI2H6/Sh7n/c4dIbUB2rZjDPaZmCZCUaEQ07w26InARFrxBBSazq C8UxrEVyFAs9FO+GYK2qbB+Ngi5s4k/uawYcGf7k0xpwVHbPx1JzMw5UY05sYM/r+MmQ GuLlnozBLpR1VNYap5VqDU2FNWqoYEC/k0uw1k1sqzYIuxfbhe2vpSLREFsOLTamgsXQ Jlu2zbz1v5nTsfZBG3oMo76oFYwOMF6DIbiqbLT2IRfZKQW9e/Jq/UsMr8HmpdG+2k2z V27A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=2noV03mEG2xilINOY7bIYeJq2mnGIWLLyr24P0XEP9A=; b=MqQjLXlyzZE5IdooSqlC8Vf0MukecVYYoBdR1XB3tNnAcozKb+FmlW6ymk2JShZhvr 6pDKYXNboYRd9L8f3Do/Rk6q9bIV7d2W1pH/t8h+GYtTsdpfJCix+2UT5LflinDDWzg+ Kp4CtpUctjEnEW0BaZoFtlK6OV+qzr9nh8DNVbruN1m44clLKNTjI8duqWlK9YG/Oyaa B2MJNSTiJT3nbQlKHptvuPDEiuCVT/3sfk9YT8mPLIpvbQXmYx8mUCCeYUapHdLMHomn +IhBwwNKjzatRowV0arZUOEk4F76Tpb3gWX5LpgxqZFucCWXeE6bzETM7pqW9XxCE5Uy IfHA== X-Gm-Message-State: AOAM530aCZhdgXIIdDBbQ6EYDPeUGk2Lq2cbPMs9Zq52KUd7nCZDKu4H aAMZk905I8En1H3xuVGcIma/1ECUkmg= X-Google-Smtp-Source: ABdhPJxM5bDG4h4yYQAqQji21BTx/cQcAEYFDCCORnJcZV6VK0T4YUkch1WvKJY1Bb6C7EqamwuI0g== X-Received: by 2002:a17:906:d92f:: with SMTP id rn15mr13210221ejb.557.1638432696985; Thu, 02 Dec 2021 00:11:36 -0800 (PST) Received: from dracor.xperim.be (82.228-200-80.adsl-dyn.isp.belgacom.be. [80.200.228.82]) by smtp.gmail.com with ESMTPSA id ht7sm1368569ejc.27.2021.12.02.00.11.36 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Dec 2021 00:11:36 -0800 (PST) Received: from [192.168.1.184] (bajor.xperim.be [192.168.1.184]) by dracor.xperim.be (Postfix) with ESMTPSA id D6AC2380051; Thu, 2 Dec 2021 09:11:35 +0100 (CET) To: bloat@lists.bufferbloat.net References: <1638390391.091227727@apps.rackspace.com> From: Jan Ceuleers Message-ID: <22dce828-cfd1-3092-ac28-7d0b0c0913c0@gmail.com> Date: Thu, 2 Dec 2021 09:11:35 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <1638390391.091227727@apps.rackspace.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Bloat] [Cerowrt-devel] uplink bufferbloat and scheduling problems 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: Thu, 02 Dec 2021 08:11:38 -0000 On 01/12/2021 21:26, David P. Reed wrote: > In any CSMA link (WiFi), there is no "up" or "down". There is only > sender and receiver, and each station and the AP are always doing both. Generally though the silicon used in WiFi APs is much more capable than that used in STAs. The capabilities of (particularly STA-side) silicon are different as they relate to uplink and downlink. Of course for a given AP-STA link a common subset of capabilities needs to be used, but that subset might be different in either direction. The antennas (number and gain), receiver sensitivity and transmit power are also different. A simple example of a reason why uplink and downlink might be different: the achievable bitrate on the AP-to-STA downlink might be higher than the uplink because the AP's transmit power is higher. In order to be able to achieve the same bitrate if the STA's transmit power is lower the AP's receiver sensitivity would have to be that much better. Generalising to other shared-media technologies: whenever the UL/DL link budgets are different the link is going to by asymmetric. Jan