From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) (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 AE9E621F1EC for ; Thu, 20 Feb 2014 14:18:18 -0800 (PST) Received: from hms-beagle.home.lan ([217.86.112.208]) by mail.gmx.com (mrgmx002) with ESMTPSA (Nemesis) id 0LmKOI-1WpOWy26lO-00ZxNp for ; Thu, 20 Feb 2014 23:18:14 +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: <530668A4.4040604@imap.cc> Date: Thu, 20 Feb 2014 23:18:13 +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> <530668A4.4040604@imap.cc> To: Fred Stratton X-Mailer: Apple Mail (2.1510) X-Provags-ID: V03:K0:tUpiySyY3LTlDDeVRNQsRCPpqouyfiKnLR7Ub6evtR7WrSV17zu 7ab2l31NlkxNAHNnP/0hBoU0+2GYOtecieBKKQAPTGfs1qThcQGKIFJt5NFIEwSYvmzeWP1 6qxtuCkvgTtYCy0pFNGFHdxpZwkd8MHrjbcrbxI9LDYrIwK9eDfhiWbh//ZZOhhuvI5Kkju VoeOyhhyPBsj8wFBgeX8g== 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 22:18:19 -0000 Hi Fred, On Feb 20, 2014, at 21:42 , Fred Stratton wrote: > ADSL2+ is better than ADSL in this context, as you point out. I = thought it was worth trying for a week or two, rather than relying = solely on the literature. So in your tests ADSL came up as the most stable solution, = interesting, real data always beats theory. Could well be the actual = modem hardware, ADSL only uses half the frequencies or the modem driver. = Or maybe your RF interferer affects the higher frequencies more. Would = be interesting to see a time resolved series of SNRM per bin plots = during on of your REINs... >=20 > The combined VDSL2/ADSL2+ approach is interesting. It is unlikely to = happen here, I think this is the future; ATM equipment is dying and telcos = try to get away from it consolidating on an ethernet based concentration = network. I am not sure whether there are any more new ADSL1 line cards = for non-ATM DSLAMs. But I could be off here as always. > as BT has an effective monopoly of fibre since its publicly-owned = competitor went bankrupt. Yeah, but even BT probably wants to retire its ATM gear and that = means replacing all DSLAMs (well the guts of the zDSLAMs). Their = backbone most likely is already pure IP and if they can get rid of the = ATM gear it will dave money, so thee is something in it for them ;) >=20 > You must be using Annex M, which here is now mainly for business use, = at extra cost. Well its Annex J (see: = http://en.wikipedia.org/wiki/G.992.3_Annex_J) which deutsche telekom = pushes as it allows coexistence with its old Annex B band plan that = allowed DSL to coexist with ISDN. Both POTS and ISDN will be retired in = Germany and replaced with carrier voice over IP. So everybody using ISDN = (and everyone using DSL and POTS) will need to be switched to all-ip; to = sweeten the change people are also getting annex J which gives a much = better upload than typical for ADSL variants. That is sort of the = publics dividend of the switch to all-ip ;) >=20 > OpenWRT test builds require an older version of uboot than the one = TP-Link uses. There is no easy regression path,and the builds are = immature. They will never allow a choice between ADSL,ADSL2, AND ADSL2+. For most users the DSLAMs are fixed to the type sold in the = plan, so switching will most likely not work anyways. >=20 > Although blogic is principal developer in Berlin, the majority of work = has been done in Polen. >=20 > Ich kann Deutsch verstehen, (the British Royal Family is more German = than a BMW) but I find Polish far more difficult. Oh, gut, ich kann Deutsch ganz passabel schreiben ;) Best Regards Sebastian >=20 >=20 > On 20/02/14 20:08, Sebastian Moeller wrote: >> Hi Fred, >>=20 >> On Feb 20, 2014, at 18:24 , Fred Stratton = wrote: >>=20 >>> 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+ ;) ) >>=20 >>> 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. >>=20 >> 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 >>>>>> 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 >>>>>>>>> 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