From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out4-smtp.messagingengine.com (out4-smtp.messagingengine.com [66.111.4.28]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id 9886B21F1A4 for ; Sun, 25 Aug 2013 12:08:05 -0700 (PDT) Received: from compute4.internal (compute4.nyi.mail.srv.osa [10.202.2.44]) by gateway1.nyi.mail.srv.osa (Postfix) with ESMTP id 17C0920FE3; Sun, 25 Aug 2013 15:08:04 -0400 (EDT) Received: from frontend2 ([10.202.2.161]) by compute4.internal (MEProxy); Sun, 25 Aug 2013 15:08:04 -0400 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=imap.cc; h=from :content-type:message-id:mime-version:subject:date:references:to :in-reply-to; s=mesmtp; bh=5NGbAicXgjL2Q9auy2lD/nUaC2Q=; b=sflM6 hHEH9QMYmwOJeRqIaYq2awBOjCe/u8UtohNpFlrlibEAjC7QitHPfHvzoK8N/L92 cFwRT6PjMfHHg0SKS0BGQFKSNp2+p67562pblvRLlSCgMyymwD0ySNOTKjCnmQZd 8CAHLP3dO2UE3Uj0fHDqcYwr3IaqJRWvQ0LV1I= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d= messagingengine.com; h=from:content-type:message-id:mime-version :subject:date:references:to:in-reply-to; s=smtpout; bh=5NGbAicXg jL2Q9auy2lD/nUaC2Q=; b=uDAtGK+sL/QBrfL1e6ts1fU1VU7+C/jWslGvugBKh xw0ZdzeDFcGFdkP7oLS249qLQOsYut2NtdbU849IeaINhQhPbmmxjo9TzeQxwms5 sT+cFBvZG6AwIh0uQwH9H6YlIiyxb8PODD3DPs+clS/AjD0wCggXgaw7eiXCannS JI= X-Sasl-enc: TcuNg7pnnpmhIAhdl/Fbun18MT0+hF+Mg+1um7exCDh8 1377457682 Received: from [172.30.42.15] (unknown [188.221.232.223]) by mail.messagingengine.com (Postfix) with ESMTPA id D9B046801B4 for ; Sun, 25 Aug 2013 15:08:02 -0400 (EDT) From: Fred Stratton Content-Type: multipart/alternative; boundary="Apple-Mail=_5AA4C2A1-7645-4048-B01F-F08BFA5035C2" Message-Id: Mime-Version: 1.0 (Mac OS X Mail 6.5 \(1508\)) Date: Sun, 25 Aug 2013 20:08:01 +0100 References: <56B261F1-2277-457C-9A38-FAB89818288F@gmx.de> <2148E2EF-A119-4499-BAC1-7E647C53F077@gmx.de> <03951E31-8F11-4FB8-9558-29EAAE3DAE4D@gmx.de> <9A9B094D-CA07-48B0-85FE-FA7C759FEDE3@gmx.de> <5BEF0C7C-C2F4-45A9-9FF2-E32A05B8D67B@gmx.de> <8CD72282-88CB-43FD-84EF-574DDB23F0AB@gmx.de> <0886582B-E46C-4F93-A9E5-C45A81C32AEA@imap.cc> <8AFDEBD8-54C9-46B6-8CBE-5CD4242A2765@imap.cc> To: "cerowrt-devel@lists.bufferbloat.net" In-Reply-To: X-Mailer: Apple Mail (2.1508) Subject: Re: [Cerowrt-devel] some kernel updates 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: Sun, 25 Aug 2013 19:08:05 -0000 --Apple-Mail=_5AA4C2A1-7645-4048-B01F-F08BFA5035C2 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 That is very helpful. With a sync rate of about 12000 kbits/s, and a download rate of about = 10900 kbits/s. I have set the download rate to 5000 kbits/s. For upload = similarly 1200/970/500, all kbits/s. I can now mostly watch video in iPlayer and download at circa 300 - 400 = kbits/s simultaneously, using htb, with tc-stab disabled. QED On 25 Aug 2013, at 19:41, Dave Taht wrote: > So it sounds like you need a lower setting for the download than what = you are using? It's not the upload that is your problem.=20 >=20 > Netanalyzer sends one packet stream and thus measures 1 queue only. = fq_codel will happily give it one big queue for a while, while still = interleaving other flows's packets into the stream at every opportunity.=20= >=20 > as for parsing rrul I generally draw a line with my hand and multiply = by 4, then fudge in the numbers for the reverse ack and measurement = streams.=20 You are saying that you judge the result solely by eye. presumably. >=20 > As written it was targetted at 4Mbit and up which is why the samples = are discontinuous in your much lower bandwidth situation.=20 Aha. Problem solved. >=20 > I do agree that rrul could use a simpler implementation, perhaps one = that tested two download streams only, and provided an estimate as to = the actual bandwidth usage, and scale below 4Mbit better. >=20 >=20 > On Sun, Aug 25, 2013 at 11:30 AM, Fred Stratton = wrote: >=20 > On 25 Aug 2013, at 18:53, Sebastian Moeller wrote: >=20 > > Hi Fred, > > > > > > On Aug 25, 2013, at 16:26 , Fred Stratton = wrote: > > > >> Thank you. > >> > >> This is an initial response. > >> > >> Am using 3.10.2-1 currently, with the standard AQM interface. This = does not have the pull down menu of your interface, which is why I ask = if both are active. > > > > I have seen your follow-up mail that you actually used = 3.10.9-2. I think that has the first cut of the script modifications = that still allow to select both. Since I have not tested it any other = way I would recommend to enable just one of them at the same time. Since = the implementation of both is somewhat orthogonal and htb_private = actually works in 3.10.9, best case you might actually get the link = layer adjustments (LLA) and the overhead applied twice, wasting = bandwidth. So please either use the last set of modified files I send = around or wait for Dave to include them in ceropackages=85 >=20 > I have retained the unmodified script. I shall return to that. >=20 >=20 > > > >> On 25 Aug 2013, at 14:59, Sebastian Moeller = wrote: > >> > >>> Hi Fred, > >>> > >>> > >>> On Aug 25, 2013, at 12:17 , Fred Stratton = wrote: > >>> > >>>> > >>>> On 25 Aug 2013, at 10:21, Fred Stratton = wrote: > >>>> > >>>>> As the person with the most flaky ADSL link, I point out that = None of these recent, welcome, changes, are having any effect here, with = an uplink sped of circa 950 kbits/s. > >>> > >>> Okay, how flaky is you link? What rate of Errors do you have = while testing? I am especially interested in CRC errors and ES SES and = HEC, just to get an idea how flaky the line is... > >>> > >>>>> > >>>>> The reason I mention this is that it is still impossible to = watch iPlayer Flash streaming video and download at the same time, The = iPlayer stream fails. The point of the exercise was to achieve this. > >>>>> > >>>>> The uplink delay is consistently around 650ms, which appears to = be too high for effective streaming. In addition, the uplink stream has = multiple breaks, presumably outages, if the uplink rate is capped at, = say, 700 kbits/s. > >>> > >>> Well, watching video is going to stress your downlink so the = uplink should not saturate by the ACKs and the concurrent downloads also = do not stress your uplink except for the ACKs, so this points to = downlink errors as far as I can tell from the data you have given. If = the up link has repeated outages however, your problems might be = unfixable because these, if long enough, will cause lost ACKs and will = probably trigger retransmission, independent of whether the link layer = adjustments work or not. (You could test this by shaping you up and = downlink to <=3D 50% of the link rates and disable all link layer = adjustments, 50% is larger than the ATM worst case so should have you = covered. Well unless you del link has an excessive number of tones = reserved for forward error correction (FEC)). > >> > >> Uptime 100655 > >> downstream 12162 kbits/s > >> CRC errors 10154 > >> FEC Errors 464 > >> hEC Errors 758 > >> > >> upstream 1122 kbits/s > >> no errors in period. > > > > Ah, I think you told me in the past that "Target snr upped to = 12 deciBel. Line can sustain 10 megabits/s with repeated loss of = sync.at lower snr. " so sync at 12162 might be too aggressive, no? But = the point is that as I understand iPlayer works fine without competing = download traffic? To my eye the error numbers look small enough to not = be concerned about. Do you know how long the error correction period is? >=20 > The correction period is probably circa 28 hours. Have moved to using = the HG612. This is uses the Broadcom 6368 SoC. Like most of the devices = I use, it fell out of a BT van and on to ebay. It is the standard device = used for connecting FTTC installations in the UK. With a simple = modification, it will work stably with ADSL2+. >=20 > Ihe sync rate has gone up considerably, not because I have changed the = Target SNR from 12 Decibel, but because I am now using a Broadcom = chipset and software blob with a DSLAM which returns BDCM when = interrogated. > > > > > >> > >>> Could you perform the following test by any chance: state = iPlayer and yor typical downloads and then have a look at = http://gw.home.lan:81und the following tab chain Status -> Realtime = Graphs -> Traffic -> Realtime Traffic. If during your test the Outbound = rate stays well below you shaped limit and you still encounter the = stream failure I would say it is save to ignore the link layer = adjustments as cause of your issues. > >> > >> Am happy reducing rate to fifty per cent, but the uplink appears to = have difficulty operating below circa 500 kbits/s. This should not be = so. I shall try a fourth time. > > > > That sounds weird, if you shape to below 500 upload stops = working or just gets choppier? Looking at your sync data 561 would fit = the ~50% and above 500 requirements. >=20 > I was basing the judgment on Netalyzr data. DT and you now say this is = suspect. However, netsurf-wrapper traces are discontinuous. The actual = real time trace looks perfectly normal. >=20 > iPlayer is a Flash based player which is web page embedded. The ipv4 = user address is parsed to see if it is in the UK. It plays BBC TV = programs. It most likely is badly designed and written. It is the way I = watch TV. Like all UK residents, I pay the bloated bureaucracy of the = BBC a yearly fee of about 200 euro. If I do not pay, I will be fined. = You will be surprised that I am not a fan of the BBC. iPlayer starts and = runs fine, but if a download is commenced whilst it is running, so I can = watch the propaganda put out as national news, the video will stall and = the continue, but most commonly will stop. > > > > > >>> > >>> > >>>>> > >>>>> YouTube has no problems. > >>>>> > >>>>> I remain unclear whether the use of tc-stab and htb are mutually = exclusive options, using the present stock interface. > >>> > >>> Well, depending on the version of the cerowrt you use, = <3.10.9-1 I believe lacks a functional HTB link layer adjustment = mechanism, so you should select tc_stab. My most recent modifications to = Toke and Dave's AQM package does only allow you to select one or the = other. In any case selecting BOTH is not a reasonable thing to do, = because best case it will only apply overhead twice, worst case it would = also do the (link layer adjustments) LLA twice > >> > >> > >>> See initial comments. > >>> > >>>>> > >>>>> The current ISP connection is IPoA LLC. > >>>> > >>>> Correction - Bridged LLC. > >>> > >>> Well, I think you should try to figure out your overhead = empirically and check the encapsulation. I would recommend you run the = following script on you r link over night and send me the log file it = produces: > >>> > >>> #! /bin/bash > >>> # TODO use seq or bash to generate a list of the requested sizes = (to alow for non-equdistantly spaced sizes) > >>> > >>> # Telekom Tuebingen Moltkestrasse 6 > >>> TECH=3DADSL2 > >>> # finding a proper target IP is somewhat of an art, just = traceroute a remote site > >>> # and find the nearest host reliably responding to pings showing = the smallet variation of pingtimes > >>> TARGET=3D87.186.197.70 # T > >>> DATESTR=3D`date +%Y%m%d_%H%M%S` # to allow multiple = sequential records > >>> LOG=3Dping_sweep_${TECH}_${DATESTR}.txt > >>> > >>> > >>> # by default non-root ping will only end one packet per second, so = work around that by calling ping independently for each package > >>> # empirically figure out the shortest period still giving the = standard ping time (to avoid being slow-pathed by our host) > >>> PINGPERIOD=3D0.01 # in seconds > >>> PINGSPERSIZE=3D10000 > >>> > >>> # Start, needed to find the per packet overhead dependent on the = ATM encapsulation > >>> # to reliably show ATM quantization one would like to see at least = two steps, so cover a range > 2 ATM cells (so > 96 bytes) > >>> SWEEPMINSIZE=3D16 # 64bit systems seem to require 16 = bytes of payload to include a timestamp... > >>> SWEEPMAXSIZE=3D116 > >>> > >>> > >>> n_SWEEPS=3D`expr ${SWEEPMAXSIZE} - ${SWEEPMINSIZE}` > >>> > >>> > >>> i_sweep=3D0 > >>> i_size=3D0 > >>> > >>> while [ ${i_sweep} -lt ${PINGSPERSIZE} ] > >>> do > >>> (( i_sweep++ )) > >>> echo "Current iteration: ${i_sweep}" > >>> # now loop from sweepmin to sweepmax > >>> i_size=3D${SWEEPMINSIZE} > >>> while [ ${i_size} -le ${SWEEPMAXSIZE} ] > >>> do > >>> echo "${i_sweep}. repetition of ping size ${i_size}" > >>> ping -c 1 -s ${i_size} ${TARGET} >> ${LOG} & > >>> (( i_size++ )) > >>> # we need a sleep binary that allows non integer times (GNU = sleep is fine as is sleep of macosx 10.8.4) > >>> sleep ${PINGPERIOD} > >>> done > >>> done > >>> > >>> #tail -f ${LOG} > >>> > >>> echo "Done... ($0)" > >>> > >>> > >>> Please set TARGET to the closest IP host on the ISP side of your = link that gives reliable ping RTTs (using "ping -c 100 -s 16 = your.best.host.ip"). Also test whether the RTTs are in the same ballpark = when you reduce the ping period to 0.01 (you might have to increase the = period until the RTTs are close to the standard 1 ping per second case). = I can then run this through my matlab code to detect the actual = overhead. (I am happy to share the code as well, if you have matlab = available; it might even run under octave but I have not tested that = since the last major changes). > >> > >> To follow at some point. > > > > Oh, I failed to mention at the given parameters the script = takes almost 3 hours, during which the link should be otherwise idle... > > > >>> > >>> > >>>> > >>>>> Whatever byte value is used for tc-stab makes no change. > >>> > >>> I assume you talk about the overhead? Missing link layer = adjustment will eat between 50% and 10% of your link bandwidth, while = missing overhead values will be more benign. The only advise I can give = is to pick the overhead that actually describes your link. I am willing = to help you figure this out. > >> > >> The link is bridged LLC. Have been using 18 and 32 for test = purposes. I shall move to PPPoA VC-MUX in 4 months. > > > > I guess figuring out you exact overhead empirically is going = to be fun. > > > >>> > >>>>> > >>>>> I have applied the ingress modification to simple.qos, keeping = the original version., and tested both. > >>> > >>> For which cerowrt version? It is only expected to do something = for 3.10.9-1 and upwards, before that the HTB lionklayer adjustment did = NOT work. > >> > >> Using 3.10.9-2 > > > > Yeah as stated above, I would recommend to use either or, not = both. If you took RRUL data you might be able to compare the three = conditions. I would estimate the most interesting part would be in the = sustained ravager up and download rates here. >=20 > How do you obtain an average i.e. mean rate from the RRUL graph? > > > > > >> > >>> > >>>>> > >>>>> I have changed the Powerline adaptors I use to ones with known = smaller buffers, though this is unlikely to be a ate-limiting step. > >>>>> > >>>>> I have changed the 2Wire gateway, known to be heavily buffered, = with a bridged Huawei HG612, with a Broadcom 6368 SoC. > >>>>> > >>>>> This device has a permanently on telnet interface, with a simple = password, which cannot be changed other than by firmware recompilation=85 > >>>>> > >>>>> Telnet, however, allows txqueuelen to be reduced from 1000 to 0. > >>>>> > >>>>> None of these changes affect the problematic uplink delay. > >>> > >>> So how did you measure the uplink delay? The RRUL plots you = sent me show an increase in ping RTT from around 50ms to 80ms with = tc_stab and fq_codel on simplest.qos, how does that reconcile with 650ms = uplink delay, netalyzr? > >> > >> Max Planck and Netalyzr produce the same figure. I use both, but = Max Planck gives you circa 3 tries per IP address per 24 hours. > > > > Well, both use the same method which is not to meaningful if = you use fq_codel on a shaped link (unless you want to optimize your = system for UDP floods :) ) > > > > [snipp] > > > > > > Best Regards > > Sebastian >=20 > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel >=20 >=20 >=20 > --=20 > Dave T=E4ht >=20 > Fixing bufferbloat with cerowrt: = http://www.teklibre.com/cerowrt/subscribe.html --Apple-Mail=_5AA4C2A1-7645-4048-B01F-F08BFA5035C2 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 That = is very helpful.

With a sync rate of about 12000 = kbits/s, and a download rate of about 10900 kbits/s. I have set the = download rate to 5000 kbits/s. For upload similarly 1200/970/500, all = kbits/s.

I can now mostly watch video in = iPlayer and download at circa 300 - 400 kbits/s simultaneously, using = htb, with tc-stab = disabled.

QED


<= div>On 25 Aug 2013, at 19:41, Dave Taht <dave.taht@gmail.com> = wrote:

So it sounds like you need = a lower setting for the download than what you are using? It's not the = upload that is your problem.

Netanalyzer sends one packet = stream and thus measures 1 queue only. fq_codel will happily give it one = big queue for a while, while still interleaving other flows's packets = into the stream at every opportunity.

as for parsing rrul I generally draw a line with my hand and = multiply by 4, then fudge in the numbers for the reverse ack and = measurement streams.

You are = saying that you judge the result solely by eye. = presumably.

As = written it was targetted at 4Mbit and up which is why the samples are = discontinuous in your much lower bandwidth situation. =

Aha. Problem = solved.

I do agree that rrul could use a simpler implementation, = perhaps one that tested two download streams only, and provided an = estimate as to the actual bandwidth usage, and scale below 4Mbit = better.


On Sun, Aug 25, 2013 at 11:30 AM, = Fred Stratton <fredstratton@imap.cc> = wrote:

On 25 Aug 2013, at 18:53, Sebastian Moeller <moeller0@gmx.de> wrote:

> Hi Fred,
>
>
> On Aug 25, 2013, at 16:26 , Fred Stratton = <fredstratton@imap.cc> = wrote:
>
>> Thank you.
>>
>> This is an initial response.
>>
>> Am using 3.10.2-1 currently, with the standard AQM interface. = This does not have the pull down menu of your interface, which is why I = ask if both are active.
>
>       I have seen your follow-up mail that you = actually used 3.10.9-2. I think that has the first cut of the script = modifications that still allow to select both. Since I have not tested = it any other way I would recommend to enable just one of them at the = same time. Since the implementation of both is somewhat orthogonal and = htb_private actually works in 3.10.9, best case you might actually get = the link layer adjustments (LLA) and the overhead applied twice, wasting = bandwidth. So please either use the last set of modified files I send = around or wait for Dave to include them in ceropackages=85

I have retained the unmodified script. I shall return to that.


>
>> On 25 Aug 2013, at 14:59, Sebastian Moeller <moeller0@gmx.de> wrote:
>>
>>> Hi Fred,
>>>
>>>
>>> On Aug 25, 2013, at 12:17 , Fred Stratton <fredstratton@imap.cc> = wrote:
>>>
>>>>
>>>> On 25 Aug 2013, at 10:21, Fred Stratton <fredstratton@imap.cc> = wrote:
>>>>
>>>>> As the person with the most flaky ADSL link, I = point out that None of these recent, welcome, changes, are having any = effect here, with an uplink sped of circa 950 kbits/s.
>>>
>>>     Okay, how flaky is you link? What rate of = Errors do you have while testing? I am especially interested in CRC = errors and ES SES and HEC, just to get an idea how flaky the line = is...
>>>
>>>>>
>>>>> The reason I mention this is that it is still = impossible to watch iPlayer Flash streaming video and download at the = same time, The iPlayer stream fails. The point of the exercise was to = achieve this.
>>>>>
>>>>> The uplink delay is consistently around 650ms, = which appears to be too high for effective streaming. In addition, the = uplink stream has multiple breaks, presumably outages, if the uplink = rate is capped at, say, 700 kbits/s.
>>>
>>>     Well, watching video is going to stress your = downlink so the uplink should not saturate by the ACKs and the = concurrent downloads also do not stress your uplink except for the ACKs, = so this points to downlink errors as far as I can tell from the data you = have given. If the up link has repeated outages however, your problems = might be unfixable because these, if long enough, will cause lost ACKs = and will probably trigger retransmission, independent of whether the = link layer adjustments work or not. (You could test this by shaping you = up and downlink to <=3D 50% of the link rates and disable all link = layer adjustments, 50% is larger than the ATM worst case so should have = you covered. Well unless you del link has an excessive number of tones = reserved for forward error correction (FEC)).
>>
>> Uptime 100655
>> downstream 12162 kbits/s
>> CRC errors 10154
>> FEC Errors 464
>> hEC Errors 758
>>
>> upstream 1122 kbits/s
>> no errors in period.
>
>       Ah, I think you told me in the past that = "Target snr upped to 12 deciBel.  Line can sustain 10 megabits/s = with repeated loss of sync.at lower snr. " so sync at 12162 might be too = aggressive, no? But the point is that as I understand iPlayer works fine = without competing download traffic? To my eye the error numbers look = small enough to not be concerned about. Do you know how long the error = correction period is?

The correction period is probably circa 28 hours. Have moved to = using the HG612. This is uses the Broadcom 6368 SoC. Like most of the = devices I use, it fell out of a BT van and on to ebay. It is the = standard device used for connecting FTTC installations in the UK. With a = simple modification, it will work stably with ADSL2+.

Ihe sync rate has gone up considerably, not because I have changed the = Target SNR from 12 Decibel, but because I am now using a Broadcom = chipset and software blob with a DSLAM which returns BDCM when = interrogated.
>
>
>>
>>>     Could you perform the following test by any = chance: state iPlayer and yor typical downloads and then have a look at = http://gw.home.lan:81und the = following tab chain Status -> Realtime Graphs -> Traffic -> = Realtime Traffic. If during your test the Outbound rate stays well below = you shaped limit and you still encounter the stream failure I would say = it is save to ignore the link layer adjustments as cause of your = issues.
>>
>> Am happy reducing rate to fifty per cent, but the uplink = appears to have difficulty operating below circa 500 kbits/s. This = should not be so. I shall try a fourth time.
>
>       That sounds weird, if you shape to below 500 = upload stops working or just gets choppier? Looking at your sync data = 561 would fit the ~50% and above 500 requirements.

I was basing the judgment on Netalyzr data. DT and you now say = this is suspect. However, netsurf-wrapper traces are discontinuous. The = actual real time trace looks perfectly normal.

iPlayer is a Flash based player which is web page embedded.  The = ipv4 user address is parsed to see if it is in the UK. It plays BBC TV = programs. It most likely is badly designed and written. It is the way I = watch TV. Like all UK residents, I pay the bloated bureaucracy of the = BBC a yearly fee of about 200 euro. If I do not pay, I will be fined. = You will be surprised that I am not a fan of the BBC. iPlayer starts and = runs fine, but if a download is commenced whilst it is running, so I can = watch the propaganda put out as national news, the video will stall and = the continue, but most commonly will stop.
>
>
>>>
>>>
>>>>>
>>>>> YouTube has no problems.
>>>>>
>>>>> I remain unclear whether the use of tc-stab and htb = are mutually exclusive options, using the present stock interface.
>>>
>>>     Well, depending on the version of the cerowrt = you use, <3.10.9-1 I believe lacks a functional HTB link layer = adjustment mechanism, so you should select tc_stab. My most recent = modifications to Toke and Dave's AQM package does only allow you to = select one or the other. In any case selecting BOTH is not a reasonable = thing to do, because best case it will only apply overhead twice, worst = case it would also do the (link layer adjustments) LLA twice
>>
>>
>>> See initial comments.
>>>
>>>>>
>>>>> The current ISP connection is IPoA LLC.
>>>>
>>>> Correction - Bridged LLC.
>>>
>>>     Well, I think you should try to figure out = your overhead empirically and check the encapsulation. I would recommend = you run the following script on you r link over night and send me the = log file it produces:
>>>
>>> #! /bin/bash
>>> # TODO use seq or bash to generate a list of the requested = sizes (to alow for non-equdistantly spaced sizes)
>>>
>>> # Telekom Tuebingen Moltkestrasse 6
>>> TECH=3DADSL2
>>> # finding a proper target IP is somewhat of an art, just = traceroute a remote site
>>> # and find the nearest host reliably responding to pings = showing the smallet variation of pingtimes
>>> TARGET=3D87.186.197.70           =      # T
>>> DATESTR=3D`date +%Y%m%d_%H%M%S`       # to = allow multiple sequential records
>>> LOG=3Dping_sweep_${TECH}_${DATESTR}.txt
>>>
>>>
>>> # by default non-root ping will only end one packet per = second, so work around that by calling ping independently for each = package
>>> # empirically figure out the shortest period still giving = the standard ping time (to avoid being slow-pathed by our host)
>>> PINGPERIOD=3D0.01             = # in seconds
>>> PINGSPERSIZE=3D10000
>>>
>>> # Start, needed to find the per packet overhead dependent = on the ATM encapsulation
>>> # to reliably show ATM quantization one would like to see = at least two steps, so cover a range > 2 ATM cells (so > 96 = bytes)
>>> SWEEPMINSIZE=3D16             = # 64bit systems seem to require 16 bytes of payload to include a = timestamp...
>>> SWEEPMAXSIZE=3D116
>>>
>>>
>>> n_SWEEPS=3D`expr ${SWEEPMAXSIZE} - ${SWEEPMINSIZE}`
>>>
>>>
>>> i_sweep=3D0
>>> i_size=3D0
>>>
>>> while [ ${i_sweep} -lt ${PINGSPERSIZE} ]
>>> do
>>>   (( i_sweep++ ))
>>>   echo "Current iteration: ${i_sweep}"
>>>   # now loop from sweepmin to sweepmax
>>>   i_size=3D${SWEEPMINSIZE}
>>>   while [ ${i_size} -le ${SWEEPMAXSIZE} ]
>>>   do
>>>     echo "${i_sweep}. repetition of ping size = ${i_size}"
>>>     ping -c 1 -s ${i_size} ${TARGET} >> = ${LOG} &
>>>     (( i_size++ ))
>>>     # we need a sleep binary that allows non = integer times (GNU sleep is fine as is sleep of macosx 10.8.4)
>>>     sleep ${PINGPERIOD}
>>>   done
>>> done
>>>
>>> #tail -f ${LOG}
>>>
>>> echo "Done... ($0)"
>>>
>>>
>>> Please set TARGET to the closest IP host on the ISP side of = your link that gives reliable ping RTTs (using "ping -c 100 -s 16 = your.best.host.ip"). Also test whether the RTTs are in the same ballpark = when you reduce the ping period to 0.01 (you might have to increase the = period until the RTTs are close to the standard 1 ping per second case). = I can then run this through my matlab code to detect the actual = overhead. (I am happy to share the code as well, if you have matlab = available; it might even run under octave but I have not tested that = since the last major changes).
>>
>> To follow at some point.
>
>       Oh, I failed to mention at the given = parameters the script takes almost 3 hours, during which the link should = be otherwise idle...
>
>>>
>>>
>>>>
>>>>> Whatever byte value is used for tc-stab makes no = change.
>>>
>>>     I assume you talk about the overhead? Missing = link layer adjustment will eat between 50% and 10% of your link = bandwidth, while missing overhead values will be more benign. The only = advise I can give is to pick the overhead that actually describes your = link. I am willing to help you figure this out.
>>
>> The link is bridged LLC. Have been using 18 and 32 for test = purposes. I shall move to PPPoA VC-MUX in 4 months.
>
>       I guess figuring out you exact overhead = empirically is going to be fun.
>
>>>
>>>>>
>>>>> I have applied the ingress modification to = simple.qos, keeping the original version., and tested both.
>>>
>>>     For which cerowrt version? It is only = expected to do something for 3.10.9-1 and upwards, before that the HTB = lionklayer adjustment did NOT work.
>>
>> Using 3.10.9-2
>
>       Yeah as stated above, I would recommend to use = either or, not both. If you took RRUL data you might be able to compare = the three conditions. I would estimate the most interesting part would = be in the sustained ravager up and download rates here.

How do you obtain an average i.e. mean rate from the RRUL = graph?
>
>
>>
>>>
>>>>>
>>>>> I have changed the Powerline adaptors I use to ones = with known smaller buffers, though this is unlikely to be a ate-limiting = step.
>>>>>
>>>>> I have changed the 2Wire gateway, known to be = heavily buffered, with a bridged Huawei HG612, with a Broadcom 6368 = SoC.
>>>>>
>>>>> This device has a permanently on telnet interface, = with a simple password, which cannot be changed other than by firmware = recompilation=85
>>>>>
>>>>> Telnet, however, allows txqueuelen to be reduced = from 1000 to 0.
>>>>>
>>>>> None of these changes affect the problematic uplink = delay.
>>>
>>>     So how did you measure the uplink delay? The = RRUL plots you sent me show an increase in ping RTT from around 50ms to = 80ms with tc_stab and fq_codel on simplest.qos, how does that reconcile = with 650ms uplink delay, netalyzr?
>>
>> Max Planck and Netalyzr produce the same figure. I use both, = but Max Planck gives you circa 3 tries per IP address per 24 hours.
>
>       Well, both use the same method which is not to = meaningful if you use fq_codel on a shaped link (unless you want to = optimize your system for UDP floods :) )
>
> [snipp]
>
>
> Best Regards
>       Sebastian

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Dave = T=E4ht

Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html=20

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