From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-x231.google.com (mail-lj1-x231.google.com [IPv6:2a00:1450:4864:20::231]) (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 204C73B2A4 for ; Thu, 27 May 2021 08:15:22 -0400 (EDT) Received: by mail-lj1-x231.google.com with SMTP id p20so486245ljj.8 for ; Thu, 27 May 2021 05:15:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=HlShwkf2McmYGri/6anJCR8ZRucI/P1+WW4iWdiiKEQ=; b=MrERBUlTwXXccK4M0ETkcbUGAwiTI4mKYet/Wm3h6Quy9vp9bYwyUG7OdNXu/tGvfo M4xNh+eAxxIbw8Zc3/GMvSL+wEX3NuUON7RkwX5yLftY7pUULa9FxF4m8fH+Ym9Gk1sc WiUPsvOmS+CvBYcipPe/ha9Jdy+DNXd07nRCrQBTnMSk/O8fHSfdAUdVRyzdDGoeWKnh bqR7Za3tc5Fy0WF0FoeoNHhu1pQMQlj0qbiv3e0fYnDBT42pBri8urjXm0ZBOEY9AfqY 5Tfwn8RmVDuYoISbfy53sLvav9DIb2GZLWks/AUBxvY8++0m3xG2HL9TEz9j6omBqlTn AoDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=HlShwkf2McmYGri/6anJCR8ZRucI/P1+WW4iWdiiKEQ=; b=I4Ez6MRw8B6BCfAMKV9xeW3CA4IEEXU8m0gfMDL57tn5KRAjvG2Et5L9mzKPiNmRV0 T9Uvy2yD0jD/EWuJfQyen+RZejQTFQPc0dIhqQ/51N/WqZBBRIBM0PseYjeLQA34y/yN VIgc+sL7WgkfvzU65N4J7e1XvwuA0vMFop+A2e2WqG7mPMtm+0gJ5pnzuCKYTOTcmz8i lpuKJP9o1VZT0LYLIvN0m/arp5mdQ8hrbRbwLR/r5KoGJReX4X8J6dexVvhWMpJhNezh DcBwic+wSPkeZDGvNMC+5GgKj0X3YXYSv1LAVI8/rUsowvwaK3ElaG0CNRUVgsaa0H+x 6WfQ== X-Gm-Message-State: AOAM531Z3RyDJlvNU1H21bND3ZOf4zTvqME70YTIl59yTqMr63hZQSUV Hg2YOnB/oDMqHs5qiRFdDqE= X-Google-Smtp-Source: ABdhPJw/3id9EGeRvWlBRiSLemCAzhK5l5csiblf6vZyf8Dc0dJ8WnLkGevmmjddr0ZPBz64C1kn0w== X-Received: by 2002:a2e:8107:: with SMTP id d7mr2307624ljg.350.1622117720950; Thu, 27 May 2021 05:15:20 -0700 (PDT) Received: from jonathartonsmbp.lan (37-136-237-77.rev.dnainternet.fi. [37.136.237.77]) by smtp.gmail.com with ESMTPSA id d3sm218192ljo.48.2021.05.27.05.15.19 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 May 2021 05:15:20 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.7\)) From: Jonathan Morton In-Reply-To: <20210527074250.E8D8740605C@ip-64-139-1-69.sjc.megapath.net> Date: Thu, 27 May 2021 15:15:18 +0300 Cc: bloat@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: <3398D6C6-9813-494E-BFC4-04FE28A56696@gmail.com> References: <20210527074250.E8D8740605C@ip-64-139-1-69.sjc.megapath.net> To: Hal Murray X-Mailer: Apple Mail (2.3445.9.7) Subject: Re: [Bloat] Educate colleges on tcp vs udp 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, 27 May 2021 12:15:22 -0000 > On 27 May, 2021, at 10:42 am, Hal Murray = wrote: >=20 > I would back up. You need to understand how networks work before = discussing=20 > TCP or UDP. >=20 > The internet is not like a phone system. There are no connections = within the=20 > network and hence no reserved bandwidth and nothing like a busy signal = to tell=20 > you that the network is full. (There are host-host connections, but = the=20 > network doesn't know anything about them.) Packets are delivered on a=20= > best-efforts basis. They may be dropped, delayed, mangled, or = duplicated. You're right - the distinction between Bell and ARPA networking is a = crucial foundation topic. A discussion of the basic 10base Ethernet PHY (and how that = fundamentally differs from the 8kHz multiplex of a traditional telephone = network) might be helpful, since the intended audience already = understands things like modulation. Once that is established, you can = talk about how reliable stream transports are implemented on top of an = ARPA-style network, using Ethernet as a concrete example. There are a lot of gritty details about how IP and TCP work that can be = glossed over for a fundamental understanding, and maybe filled in later. = Things like Diffserv, the URG pointer, option fields, and socket = timeouts are not relevant topics. There's no need to actually hide them = from a header diagram, but just highlight the fields that are = fundamental to getting a payload from A to B. - Jonathan Morton=