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 BCB3721F243 for ; Thu, 20 Feb 2014 06:38:15 -0800 (PST) Received: from u-089-d005.biologie.uni-tuebingen.de ([134.2.89.5]) by mail.gmx.com (mrgmx103) with ESMTPSA (Nemesis) id 0MgKoE-1Watgw1DsM-00NgRe for ; Thu, 20 Feb 2014 15:38:12 +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: <530609BE.6030508@imap.cc> Date: Thu, 20 Feb 2014 15:38:11 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: <5FCE9372-5DCD-4CDD-885C-706B5A7F19A2@gmx.de> References: <53059269.1000300@imap.cc> <5305E875.9070508@imap.cc> <5305E893.8020604@imap.cc> <5306099C.1090604@xyz.am> <530609BE.6030508@imap.cc> To: Fred Stratton X-Mailer: Apple Mail (2.1510) X-Provags-ID: V03:K0:Trrg+fKSqi1aNS0GCQ4m1bZ4pyPFjqNU+/FZIgkSn0PxHRm1EoU PQjVEwQTlExIDkqHloj/z96hBGa41rTtOuJb+MTolFPYUQlnepPjqK4oS6se04cyES4fZGA VIyfppl88y7V4OSmC/wYvv/lDjfjwRm7qVbEZljgSv6HvNRdNL8arVRQmS5XPpz66FQMjra 9wyRdLbtYcZzm/GhWbuDQ== Cc: cerowrt-devel@lists.bufferbloat.net Subject: Re: [Cerowrt-devel] just when I thought it was safe to do a release 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: Thu, 20 Feb 2014 14:38:16 -0000 Hi Fred, On Feb 20, 2014, at 14:57 , Fred Stratton wrote: >=20 > On 20/02/14 13:56, Fred Stratton wrote: >> The DSLAM at the exchange is an Infineon, Germany's finest. The issue I mentioned did not happen at the DSLAM so sync was = not affected, but at the PPPoE termination point, the BRAS, which = accidentally throttles a number of users below their rated bandwidths, = rather obscure and since restricted to ADSL1 hopefully a legacy issue = that will go away at latest once all ADSL1 line cards are retired... >>=20 >> I am using a 2Wire 2700 as the bridged connection device. The higher = frequency bins, as graphed, as not optimally used. The device uses = ADSL2+. The user cannot change this mode. >>=20 >> The 2Wire is very effective at suppressing impulse noise. >>=20 >> The line is uncapped, with unlimited downloads. Just as I remembered, that means that syncing at good line = moments just does not leave enough slack-bits for worse-case scenarios, = hence your approach to increase the line tolerance by increasing SNRM to = be better equipped for your sync to survive the interference episodes=85 = It is a pity that one can not really request the modem to only sync at a = specific bandwidth directly. =20 >>=20 >> The RF Interference source is unknown. Possible culprits are >>=20 >> analogue to digital set top TV conversion boxes. >> passing vehicles. >> holes in the ionosphere. >>=20 >> http://www.bath.ac.uk/elec-eng/invert/iono/rti.html >>=20 >> I can find no PPPoE errors. Then I think that cerowrt should have no effect on the wan = speed. >>=20 >> The neighbours, based on their SSIDs, are always changing ISPs, and = so are not a constant source of RF interference in that sense. Well, evenif everybody uses BT's infrastructure there still can = be some shared cable segments which can cause cross-talk. So even a = local loop unbundled ISP that runs its own DSLAM-lincards at the central = office will have some of its wire share a bundle with other ISP's wire = along the lines to the Serving area interface, and that is sufficient = for degradation of your line capacity. Only if your neighbors and you = directly connect to two different outdoor slams/msans you would be not = affected by their del usage. And if you suspect that they cause true RF = interference, that can come easily in via the power lines=85 Since we = humans have no good sense for electrical fields locating the source of = RF interferes is a black art=85 Best Regards Sebastian >>=20 >>=20 >> On 20/02/14 13:15, Sebastian Moeller wrote: >>> Hi Fred, >>>=20 >>>=20 >>> On Feb 20, 2014, at 12:35 , Fred Stratton = wrote: >>>=20 >>>> On 20/02/14 11:35, Fred Stratton wrote: >>>>> I am aware of the DSLStats executable produced by Bald_Eagle on = Kitz. >>>>>=20 >>>>> This was designed primarily with the Huawei HG 612 in mind, for = VDSL2 connection monitoring. >>>>>=20 >>>>> I have used an HG 612 with ADSL2plus, but telnet is permanently = available, with the password 'admin', a feature I do not like, even on a = bridged device. >>> Ah, that sounds not very safe (would it hurt the manufacturers to = switch to ssh on those devices and allow users to change the password, = or better ship units with unique and secure passwords, especially = irritating since many modems actually run linux inside...) >>>=20 >>>>> Routerstats is not reliant on telnet. >>> Ah, I see it only extracts "Downstream Noise Margin and = Connection Speed", I now see why you recommend the use of SNRM as proxy = for line-quality ;)... >>>=20 >>>=20 >>>>> I appreciate the analysis, which I am sure is correct. >>> I certainly hope it is, but while phrased as statements instead = of questions, I might be completely out for lunch here; then gain I am = always happy to learn from my mistakes... >>>=20 >>>>> I am interested in external RF interference primarily. I have had = two episodes of possible interference recently, leading to transient = disconnections. >>> Well, especially for RF interference a time resolved plot of = CRCs, HECs, and even FECs (which should also increase massively around = noise events) would be even better. Also some modems give ES (errored = seconds) and SES (severely errored seconds) which are also good to plot = along time. >>>=20 >>>>> Continuously monitoring noise margin not only tells you when your = neighbours get up, but also what is happening 40km above. >>>>>=20 >>>>> The thought was that it would be useful for others, to measure = noise margin to track whether the phenomenon I am noticing when this one = new build of ceroWRT was released - transient disconnection - is related = to that build, or not. I am hoping for longer term benefits also. >>> Mmmh, if the modem concurrently looses sync than cerowrt should = be innocent, if sync stays up and you have PPPoE errors (and run PPPoE = from cerowrt) only with a certain cerowrt build you have a strong case = for cero's involvement. >>>=20 >>>>> When David P says his speed has increased, I listen. Here, I = upgraded ceroWRT and had a transient rise in WAN sync speed almost = immediately before the first connection loss. >>> You have an open profile (I mean you are limited by line physics = and not throttled below that by your ISP), right? If all your neighbors = switch of their modems and your intermittent RF noise source also = sleeps, you will get a high sync value where all frequency bins are = maximally used (so only little room for bitswitching). Now either = cross-talk increases due to mode xDSL activity at your DSLAM or the RF = noise comes back. Now your sync is exceeding the new line capacity = caused by the changed line conditions and there goes your sync. Then on = resync with the new conditions the system syncs at lower bandwidth to = honor the specified SNRM under the new conditions, and you have again = only a little leeway for bit switching, but yuo start at a level better = matched to your average line condition, so this works better than = basically the same amount of spare bits after a sync with perfect = conditions. >>> Now this only applied if there was a resync of the modem after = re-installation of cerowrt=85 If you did not re-sync (either you or the = modem by its own) then it gets puzzling, as all cerowrt does, if I = remember your setup correctly, is to do the PPPoE encapsulation, and = that should not affect your speed one iota. >>> (That said, there seems to be a buggy BRAS version by cisco = around, that in germany causes people on old ADSL DSLAMs that hook up to = the ATM concentration net to get throttled by the BRAS by reducing the = PPPoE en- and decapsulation speed. But that is so obscure that I do not = think it affects you, heck it might be a pure duetsche telekom issue). >>>=20 >>>>> Coincidence or not, the only way to know is by someone, somewhere, = monitoring their connection. >>> I fully endorse that! Monitoring the DSL statistics is a good = practice (I would love doing it again, but my current modem-router has = no meaning flu way of doing that=85) >>>=20 >>>=20 >>> Best Regards >>> Sebastian >>>=20 >>>=20 >>>>>=20 >>>>>=20 >>>>>=20 >>>>> On 20/02/14 09:05, Sebastian Moeller wrote: >>>>>> Hi Fred, >>>>>>=20 >>>>>>=20 >>>>>> On Feb 20, 2014, at 06:28 , Fred Stratton = wrote: >>>>>>=20 >>>>>>> http://www.vwlowen.co.uk/internet/files.htm#routerstatslite >>>>>>>=20 >>>>>>> is software that is useful for monitoring an ADSL connection. = When 'speed has increased' is mentioned, I wonder what has happened to = the downstream noise margin. >>>>>> I think, DP reported speed increase of the wireless (swN0) to = wired (se00) subnets on his home network, not necessarily increases in = wan speed... >>>>>>=20 >>>>>> Interesting point though; I think with DSL there is a weak = correlation between link stability/speed with noise margin. But other = variables should have stronger correlation with useable bandwidth than = noise margin. >>>>>> Here is why; as far as I know seamless rate adaptation (SRA) is = not in use, so generally speaking the sync speed of a typical DSL link = will over time degrade (and not increase, ignoring G.inp). So once a DSL = connection has "aged" down to stable conditions, noise margin what ever = the numerical values are will not affect the speed. (Note typically the = noise margin is something that is configured in the DSLAM/modem as = minimums; each frequency bin is only maximally loaded with bits that = this minimum signal to noise margin remains. If the link is throttled = below full sync speeds, say by contract, e.g. having a 6M plan on a = short line that would support 16M, then the noise margin will be large = and the system has lots of freedom how many bits to load on each = frequency bin. If the link is running at full sync, basically close to = the physical limits of the link the noise margin will be close to the = minimum values configured by the ISP. If the physical condition change, = say more cross-talk noise due to more active DSL links in the = DSLAM/trunk line the modem in the second situation will probably loose = sync and resync at lower bandwidth but with noise margin still at the = configured minimum. In other words in that situation noise margin will = not correlate with link speed). >>>>>> However CRC and HEC error counts should correlate well with = perceived speed changes, as both require packet retransmissions (visible = to the ensures network stack, basically those packets are just dropped = reducing good put, but at least the end nodes have a good understanding = what is pushed over the DSL wires) degrading the good put of the link. = Granted, with a low noise margin CRCs are more likely, but it is the = errors and not the noise margin that actually affect the speed. (And lo = and behold with some interference sources even very large noise margins = do not prevent CRCs sufficiently). >>>>>> Note the number of FECs (forward error correction) is = irrelevant to the speed, as the link carries the FEC information anyway, = so no slowdown for FEC (well, actually with G.inp that changes a bit, as = now the physical layer tries to retransmit packets/atm cells garbled = beyond recognition by noise; effectively reducing the link throughput in = an opaque way for the endnotes. Which will cause issues with using a = shaper not intimately linked to the actual xDSL modem. But I have only = glanced over = https://www.itu.int/rec/dologin_pub.asp?lang=3De&id=3DT-REC-G.998.4-201006= -I!!PDF-E&type=3Ditems so I might be too pessimistic). >>>>>>=20 >>>>>>=20 >>>>>>=20 >>>>>>> Runs prettily under Wine, and is maintained, unlike DMT. >>>>>> A great, just to complete the list for some broadcom models: = http://www.s446074245.websitehome.co.uk under active development... >>>>>>=20 >>>>>>=20 >>>>>> Best Regards >>>>>> Sebastian >>>>>>=20 >>>>>>>=20 >>>>>>> On 19/02/14 16:38, David Personette wrote: >>>>>>>> I check for updates to certain projects each morning... I can = quit anytime I want... =3D) >>>>>>>>=20 >>>>>>>> I hadn't enabled ipv6 again since the hurricane tunnels have = been fixed, I'll do so tonight. Thanks again. >>>>>>>>=20 >>>>>>>> --=20 >>>>>>>> David P. >>>>>>>>=20 >>>>>>>>=20 >>>>>>>> On Wed, Feb 19, 2014 at 11:29 AM, Dave Taht = wrote: >>>>>>>> On Wed, Feb 19, 2014 at 11:11 AM, David Personette = wrote: >>>>>>>>> I installed 3.10.28-12, and other than some missing packages = (bash and curl >>>>>>>> Heh. What do you guys do, have a cron job polling for changes = to the build dir? >>>>>>>> :) >>>>>>>>=20 >>>>>>>> I was going to sit on that and put out a more polished version = sometime in >>>>>>>> the next couple days. >>>>>>>>=20 >>>>>>>>> were what I noticed, and pulled from the previous version >>>>>>>> I killed some big packages while trying to get a new build done = faster. >>>>>>>>=20 >>>>>>>> I'll sort through the missing ones and add them back in. (I = also just >>>>>>>> added in squid, per request). Got a big build box donated to = use >>>>>>>> again, post disaster. >>>>>>>>=20 >>>>>>>> Does anyone care about cups? (printing?) It was one of those = things that >>>>>>>> just barely works in the first place due to memory constraints = and a PITA >>>>>>>> and I haven't shipped it in a while. Most printers are network = capable >>>>>>>> these days, and what I tend to use the usb port for is odd = devices >>>>>>>> and gps and the like. I'd like to have support for a 3g modem = or two... >>>>>>>>=20 >>>>>>>> Two concerns of mine are that I killed off udev, which used to = manage >>>>>>>> hotplugging. I'd like to know what, if anything, people are = using the usb >>>>>>>> for, so as to be able to make sure losing udev doesn't break = that... >>>>>>>>=20 >>>>>>>>> comcast/3.10.28-4). It's working great for me. Throughput on = WiFi from my >>>>>>>>> laptap to wired server is up, from 7-9MB to 10-12MB. Thank = you. >>>>>>>> I still think there is some tuning to be done on a rrul load, = but we had >>>>>>>> to get the last of the instruction traps out of the way first. = As of >>>>>>>> this morning >>>>>>>> so far as I know, the "last" ones are gone, but I don't want to = jinx it... >>>>>>>>=20 >>>>>>>> Did you try ipv6? Default routes are not quite working for me = in >>>>>>>> a couple scenarios. >>>>>>>>=20 >>>>>>>>> --=20 >>>>>>>>> David P. >>>>>>>>>=20 >>>>>>>>>=20 >>>>>>>>> On Tue, Feb 18, 2014 at 5:49 PM, Dave Taht = wrote: >>>>>>>>>> ok, so all the bits flying in loose formation have been = rebased on top of >>>>>>>>>> openwrt head, and I've submitted the last remaining = differences (besides >>>>>>>>>> SQM) up to openwrt-devel. They immediately took one... >>>>>>>>>>=20 >>>>>>>>>> I also went poking through current 3.14rc kernels to find = bugs fixed there >>>>>>>>>> but >>>>>>>>>> not in stable 3.10. Found two more I think. (one elsewhere in = the flow >>>>>>>>>> hash that I had >>>>>>>>>> just submitted upstream, sigh). Tried to backport sch_fq and = sch_hhf, >>>>>>>>>> failed, >>>>>>>>>> gave up on tracking pie further. >>>>>>>>>>=20 >>>>>>>>>> So I got a new build going, including dnsmasq with dnssec, = tested the >>>>>>>>>> components, >>>>>>>>>> and was ready to release... >>>>>>>>>>=20 >>>>>>>>>> ... when a whole boatload of other stuff landed. Doing a new = build now... >>>>>>>>>>=20 >>>>>>>>>> and taking the rest of the day off. >>>>>>>>>>=20 >>>>>>>>>>=20 >>>>>>>>>> --=20 >>>>>>>>>> Dave T=E4ht >>>>>>>>>>=20 >>>>>>>>>> Fixing bufferbloat with cerowrt: >>>>>>>>>> http://www.teklibre.com/cerowrt/subscribe.html >>>>>>>>>> _______________________________________________ >>>>>>>>>> Cerowrt-devel mailing list >>>>>>>>>> Cerowrt-devel@lists.bufferbloat.net >>>>>>>>>> https://lists.bufferbloat.net/listinfo/cerowrt-devel >>>>>>>>=20 >>>>>>>> --=20 >>>>>>>> Dave T=E4ht >>>>>>>>=20 >>>>>>>> Fixing bufferbloat with cerowrt: = http://www.teklibre.com/cerowrt/subscribe.html >>>>>>>>=20 >>>>>>>>=20 >>>>>>>>=20 >>>>>>>> _______________________________________________ >>>>>>>> Cerowrt-devel mailing list >>>>>>>>=20 >>>>>>>> Cerowrt-devel@lists.bufferbloat.net >>>>>>>> https://lists.bufferbloat.net/listinfo/cerowrt-devel >>>>>>> _______________________________________________ >>>>>>> Cerowrt-devel mailing list >>>>>>> Cerowrt-devel@lists.bufferbloat.net >>>>>>> https://lists.bufferbloat.net/listinfo/cerowrt-devel >>>>>=20 >>=20 >>=20 >=20