From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.20]) (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 9148D3B29E for ; Wed, 13 Dec 2017 07:36:12 -0500 (EST) Received: from [192.168.250.101] ([134.76.241.253]) by mail.gmx.com (mrgmx101 [212.227.17.168]) with ESMTPSA (Nemesis) id 0MeLKt-1efuar1T3v-00QDgr; Wed, 13 Dec 2017 13:36:10 +0100 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 10.3 \(3273\)) From: Sebastian Moeller In-Reply-To: Date: Wed, 13 Dec 2017 13:36:09 +0100 Cc: Jonathan Morton , bloat Content-Transfer-Encoding: quoted-printable Message-Id: <9E518E4F-0DCA-4B28-B01D-612201FEE493@gmx.de> References: <4D0E907C-E15D-437C-B6F7-FF348346D615@gmx.de> <019064B3-835C-4D59-BE52-9E86EE08CD02@gmx.de> To: Mikael Abrahamsson X-Mailer: Apple Mail (2.3273) X-Provags-ID: V03:K0:He9/3Jb78BuIHTdBGzMZANtyDs+Pb6qKMNaCP3Xe2qFjMdtbLc2 vNCkaWcrEdciaDDP0LCss1Gt2B4PcX4k3ohBzjmInt/p4Kz7/icJrOep2fLxKLj2i4V2qZV w0McdE1TVpUIdrQX8WnDBQMzU6uQEgFZOvYUf4sYycAAiMlsDdsWjW/TnU4M25QatWVUuwr 0GRuQ6GfA4Ly6M/PyH9hA== X-UI-Out-Filterresults: notjunk:1;V01:K0:HCYhaY+6lik=:t+Sti50rEEQ+9bzpGo5gPY qBigjVY83OUyaTzGNdC6TQevI5PQZMuYEjGD7/XU/rdlloSH+dnvzj8N8rOtFeoduypy/wvAY Az2AI3bjHdextOyXuxZJIGYJPLBg2knLQmuf9Lk3lnF5mZ/og1NdIPpwhekDJLFj53S1E2XuO 6nIJ1JXGcxxadmXXr2GbhhzyDmy88s/FY4TmwaWiqwd/Sh3il5jlYfnicLJaxOcNznYFA6LYZ PqnhfMMm3O+BmkJSWbqXtDA9tP7DxUf1SYIe4oBppUpnDwVCG7J2WQ/IYETXnKTMZ8GbA8uO+ U9FrB+UzfB5bOklLj/CTQuaRJ1/oQ8nV+wgv2RAMXnIhPnaIaod8v0BBZpXzXWJGeWmu/beJ6 Um3voYFgBnrYLlv2BVq8sNV1UySRLvus18YUx6osTUjJGBCg2QutmB5c6OwwgIvio3jRP6d4n Gd9SyrgreaCJxozUB6H4xjcKnLoDj3jhqAeCPjZLb9JkD6/cRDJwf1xsh44cwI+GCvqmfT7I+ BrGXNlP/Spv0sltILoszl3vu2YdI/KXXkP2lJ+qy016onzDWnqLLiwypWMTKytEQ0hGmBY13F zK6kltH22NAISL0TMdOuS5r424TmRyfS0U7fHb3TPcMFlV8crYHf8b+jFyb6BEIzl42kLrw71 TDR6ok0bJUQ3nHqwUq/skjpod51TMeY4r6FutuzktZYH8TLFz/0CWj+nInaowREZZ7UTCg4I8 qR+wqn4P8rVPnaIua63nPbkSI5wmzdtaiyMzOsgyzgqC0fFn+RGUV45DdTBTOA6nkOSbKGanv 1lR+dF6rFCNa9iJP4SfASviui407VU/2E1kUe4opwU8Kvg0paw= Subject: Re: [Bloat] benefits of ack filtering 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: Wed, 13 Dec 2017 12:36:12 -0000 Hi Mikael, > On Dec 13, 2017, at 10:46, Mikael Abrahamsson = wrote: >=20 > On Wed, 13 Dec 2017, Jonathan Morton wrote: >=20 >> the uplink shaper is set to about a fiftieth of that. I seriously = doubt that DOCSIS is ever inherently that asymmetric. >=20 > Well, the products are, because that's what the operators seems to = want, probably also because that's what the customers demand. Not 100% about the demand; I believe this also has a component = of market segmentation: a) everybody that actually wants to offer content is going to be not to = well-served with the asymmetric links and hence might need to upgrade to = the typical business-grade contracts that AFAIKT often have smaller = download/upload ratios. b) I seem to recall (but can find no evidence, so I might fantasizing) = that having assymmetric traffic can have advantages for an ISP with = peering/transit costs. >=20 > So my modem has 16x4 (16 downstream channels and 4 upstream channels), = meaning built into the hardware, I have 1/4 split. In addition to the differences in available modulations for = down- and upstream channels. >=20 > Then providers typically (this is my understanding, I haven't worked = professionally with DOCSIS networks) do is they have 24 downstream = channels and 4 upstream channels. Older modems can have 8 downstream and = 4 upstream for instance, so they'll "tune" to the amount of channels = they can, and then there is an on-demand scheduler that handles upstream = and downstream traffic. >=20 > So I guess theoretically the operator could (if large enough) make a = hw vendor create a 16x16 modem and have 32 channels total. > But nobody does that, because that doesn't sell as well as having more = downstream (because people don't seem to care about upstream). Or because more symmetric offers can be sold for more money to = businesses (sure the "business" contract class probably offers more than = that, but I think this is one thing it does offer). > It just makes more market sense to sell these asymmetric services, = because typically people are eyeballs and they don't need a lot of = upstream bw (or think they need it). Let's put it that way, people simply do not know as in the = advertisements one typically only sees the downstream numbers with the = upstream relegated to the footnotes (or hidden behind a link). If = customers truly would not care ISPs could afford to be more open with = the upstream numbers (something regulators would certainly prefer to = hiding the information in the fine print). >=20 > On the ADSL side, I have seen 28/3 (28 down, 3 up) for annex-M with = proprietary extensions. The fastest symmetric I have seen is 4.6/4.6. So = if you as an operator can choose between selling a 28/3 or 4.6/4.6 = service, what will you do? To consumers, it's 28/3 all day. I agree that most users would see it that way (especially since = 4.6 to 3 is not that much loss); also I b;eive it will be hard to offer = simultaneous 23/3 and 4.6/4.6 over the same trunk line (not sure whether = that is the correct word, I mean the thick copper cable "tree" that = starts from the CO/gf-attached DSLAM). For ADSL the challenge is that the up-/downstrewam bands need to = be equal for all users on a trunk cable other wise interference/cross = talk will be bad; and the most remote customer will still need some = downstream effectively limiting the high end for the single upstream = band in ADSL. VDSL2 sidesteps this issue somewhat by using multiple = upstream bands and more remote lines will simply miss out on the higher = frequency upstream bands but will still get a better symmetry... >=20 > So people can blame the ISPs all day long, but there is still (as you = stated) physical limitations on capacity on RF spectrum in air/copper, These limitations might or might not be close: = https://www.assia-inc.com/wp-content/uploads/2017/05/TDSL-presentation.pdf= > and you need to handle this reality somehow. If a lot of power is used = upstream then you'll get worse SNR for the downstream, meaning less = capacity overall. Symmetric access capacity costs real money and results = in less overall capacity unless it's on point to point fiber. Best Regards Sebastian >=20 > --=20 > Mikael Abrahamsson email: swmike@swm.pp.se > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat