From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.22]) (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 A2FA821F18F for ; Thu, 20 Feb 2014 12:08:32 -0800 (PST) Received: from hms-beagle.home.lan ([217.86.112.208]) by mail.gmx.com (mrgmx103) with ESMTPSA (Nemesis) id 0LzbXq-1XK4rP0NVK-014gdp for ; Thu, 20 Feb 2014 21:08:29 +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: <53063A54.9050102@imap.cc> Date: Thu, 20 Feb 2014 21:08:29 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: References: <53059269.1000300@imap.cc> <5305E875.9070508@imap.cc> <5305E893.8020604@imap.cc> <5306099C.1090604@xyz.am> <530609BE.6030508@imap.cc> <5FCE9372-5DCD-4CDD-885C-706B5A7F19A2@gmx.de> <53063A54.9050102@imap.cc> To: Fred Stratton X-Mailer: Apple Mail (2.1510) X-Provags-ID: V03:K0:C7JZnc5y/53s9UWHy7Y91tc9norItfJtb/zP1KWl/7aqI9loZSJ XLlIpo8XxjF3+ekGb1e0Em0AfXxAzln5yAMMxjDeuzdTZQ9BgeiyvEDuPK3S72TJk8sPyvC IOXjLMCemULwiKJQEgSVPDCCwLm4Sp3kxjVyvpC6ggK+3xFrvd1x0bTzDUEFroHBM08vJZY zGE4tOhDCRurA1lJYwW0w== 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 20:08:33 -0000 Hi Fred, On Feb 20, 2014, at 18:24 , Fred Stratton wrote: > Aha.. beyond the DSLAM... >=20 > I was unaware of that BRAS PPPoE issue. And there is no good reason to be aware of that particular = screw-up :) >=20 > Before using the 2Wire, I was using aTD-W9870, with a Lantiq chipset. = The manufacturers firmware allows you to choose ADSL2+, or ADSL2, or = ADSL, specifically. My observation in the past was that the DSLAM has to play along; = if you try ADSL2 on a ADSL1 line card it will just not sync. Now the = ISPs are free to expose several modes on the same line card if they want = to. At least in Germany the trend seems to be combined VDSL2/ADSL2+ line = cards (with ADSL2+ as fall back for long distances and customers with = old modems) >=20 > As you would expect ADSL had the least problems, and gave a full 8 = megabits/s. I could easily be off, but from looking at the standards I would = have guessed that ADSL2+ would be more resilient against interference = (at the same bandwidth as ADSL1 it should be more robust, but I assume = most modems will trade this additional robustness for higher sync) >=20 > The 2Wire has far fewer problems with the frequent lease renewals the = ISP imposes. The TD-W8970 has odd problems. Did you use openwrt on the TD-W8970 rot stock firmware? >=20 > You are correct. Most of the telephone cable is shared to the = exchange. Most properties have a 10-pair cable, where only one pair is = used. Bit-swapping is supposed to mitigate against crosstalk. Yes, but I can only do so much, vectoring will help a lot in = that regard (by measuring the cross-talk and shaping all signals so that = the look great after experiencing cross-talk; pretty cool technology, = but also a computational expensive way to push the inevitable = fiber-to-the-home further into the future). >=20 > Even when FTTC appears, all cables will be adjacent up to the local = MSAN. This is why vectoring, with its promise to eradicate DSLAM NEXT = and line FEXT almost completely, is going to help a lot. Since fiber is = not an option, I am looking forward to switching to that, 100Mbit in 40 = Mbit out also is a much saner asymmetry than my current 16in 2.5 out = (which is actually quite reasonable for ADSL2+ ;) ) > I doubt I shall go that route. I have cable outside the front door = already, which nobody uses, as they are still trying to recoup their = infrastructure costs - approx 1.5 milliard euro. All the pit covers say = 'NYNEX' on them. Well, in germany cable download looks quite nice but the upload = with 5M max (2-4 typical) is not quite as good as current VDSL offers = (10up) and definitely way off the promised 40up; also a cable node in = germany shares ~400MBit among its users while VDSL typical shares 1Gbit. best regards Sebastian >=20 > To get back on-topic, I accept that it is unlikely that cero has = affected the situation. >=20 >=20 >=20 > On 20/02/14 14:38, Sebastian Moeller wrote: >> Hi Fred, >>=20 >> 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 >>>> 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 >>=20 >> 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 >>>>>>> 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 >>>>>>>>> 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 >>>>>>>>>> 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