From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.15]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id F195521F100 for ; Sat, 28 Dec 2013 02:01:34 -0800 (PST) Received: from [192.168.2.43] ([79.202.23.202]) by mail.gmx.com (mrgmx001) with ESMTPSA (Nemesis) id 0MBExR-1VnC3i2wDd-00AEtw for ; Sat, 28 Dec 2013 11:01:32 +0100 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 6.6 \(1510\)) From: Sebastian Moeller In-Reply-To: <75A7B6AE-8ECA-4FAC-B4D3-08FD14078DA2@gmail.com> Date: Sat, 28 Dec 2013 11:01:29 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: References: <75A7B6AE-8ECA-4FAC-B4D3-08FD14078DA2@gmail.com> To: Rich Brown X-Mailer: Apple Mail (2.1510) X-Provags-ID: V03:K0:9wPvuRFDnEGIbWsPPx5leApelLdOawFByH5sx+JdXYCqvK1wMMw sWH0oYnBa5IvbHOWiWYhyu/EDAuvaq92P+NUTbs8yDX8IAcQ71XPUe+5JuFwBYP0SG9LqAe E9xt3brK4rYMvYsqTY7eAADXCShuS4MFgxDGTUneSCPVY6iFwFdpx2KELnlR73WY+sZ0IZS zc9nLdfX5c1A5j6b1msZg== Cc: cerowrt-devel Subject: Re: [Cerowrt-devel] Update to "Setting up SQM for CeroWrt 3.10" web page. Comments needed. X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 28 Dec 2013 10:01:35 -0000 Hi Rich, great! A few comments: Basic Settings: [Is 95% the right fudge factor?] I think that ideally, if we get can = precisely measure the useable link rate even 99% of that should work out = well, to keep the queue in our device. I assume that due to the = difficulties in measuring and accounting for the link properties as link = layer and overhead people typically rely on setting the shaped rate a = bit lower than required to stochastically/empirically account for the = link properties. I predict that if we get a correct description of the = link properties to the shaper we should be fine with 95% shaping. Note = though, it is not trivial on an adel link to get the actually useable = bit rate from the modem so 95% of what can be deduced from the modem or = the ISP's invoice might be a decent proxy=85 [Do we have a recommendation for an easy way to tell if it's working? = Perhaps a link to a new Quick Test for Bufferbloat page. ] The linked = page looks like a decent probe for buffer bloat. > Basic Settings - the details... >=20 > CeroWrt is designed to manage the queues of packets waiting to be sent = across the slowest (bottleneck) link, which is usually your connection = to the Internet. I think we can only actually control the first link to the ISP, = which often happens to be the bottleneck. At a typical DSLAM (xDSL head = end station) the cumulative sold bandwidth to the customers is larger = than the back bone connection (which is called over-subscription and is = almost guaranteed to be the case in every DSLAM) which typically is not = a problem, as typically people do not use their internet that much. My = point being we can not really control congestion in the DSLAM's uplink = (as we have no idea what the reserved rate per customer is in the worst = case, if there is any). > CeroWrt can automatically adapt to network conditions to improve the = delay/latency of data without any settings. Does this describe the default fq_codels on each interface = (except fib?)? > However, it can do a better job if it knows more about the actual link = speeds available. You can adjust this setting by entering link speeds = that are a few percent below the actual speeds.=20 >=20 > Note: it can be difficult to get an accurate measurement of the link = speeds. The speed advertised by your provider is a starting point, but = your experience often won't meet their published specs. You can also use = a speed test program or web site like http://speedtest.net to estimate = actual operating speeds. While this approach is commonly recommended on the internet, I = do not believe that it is that useful. Between a user and the speediest = site there are a number of potential congestion points that can affect = (reduce) the throughput, like bad peering. Now that said the sppedtets = will report something <=3D the actual link speed and hence be = conservative (interactivity stays great at 90% of link rate as well as = 80% so underestimating the bandwidth within reason does not affect the = latency gains from traffic shaping it just sacrifices a bit more = bandwidth; and given the difficulty to actually measure the actually = attainable bandwidth might have been effectively a decent recommendation = even though the theory of it seems flawed) > Be sure to make your measurement when network is quiet, and others in = your home aren=92t generating traffic. This is great advise. I would love to comment further, but after reloading = http://www.bufferbloat.net/projects/cerowrt/wiki/Setting_up_AQM_for_CeroWr= t_310 just returns a blank page and I can not get back to the page as of = yesterday evening=85 I will have a look later to see whether the page = resurfaces=85 Best Sebastian On Dec 27, 2013, at 23:09 , Rich Brown wrote: >> You are a very good writer and I am on a tablet. >>=20 > Thanks! >> Ill take a pass at the wiki tomorrow. >>=20 >> The shaper does up and down was my first thought... >>=20 > Everyone else=85 Don=92t let Dave hog all the fun! Read the tech note = and give feedback! >=20 > Rich >=20 >> On Dec 27, 2013 10:48 AM, "Rich Brown" = wrote: >> I updated the page to reflect the 3.10.24-8 build, and its new GUI = pages. >>=20 >> = http://www.bufferbloat.net/projects/cerowrt/wiki/Setting_up_AQM_for_CeroWr= t_310 >>=20 >> There are still lots of open questions. Comments, please. >>=20 >> Rich >> _______________________________________________ >> Cerowrt-devel mailing list >> Cerowrt-devel@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/cerowrt-devel >=20 > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel