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 TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 8114A3B25E for ; Fri, 10 Jun 2016 01:20:19 -0400 (EDT) Received: from [10.137.13.46] ([95.91.197.216]) by mail.gmx.com (mrgmx003) with ESMTPSA (Nemesis) id 0MQQzk-1b1ICb2u2W-00TpHD; Fri, 10 Jun 2016 07:20:17 +0200 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) From: moeller0 In-Reply-To: <3d4cdbf4-42dd-a371-2d44-f1bad6505684@gmail.com> Date: Fri, 10 Jun 2016 07:20:17 +0200 Cc: cake@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: References: <7409a52d-8c81-25f0-e070-c7638fdf9d83@gmail.com> <0B4652E3-F061-479D-8BB3-EA0193333A51@gmx.de> <3d4cdbf4-42dd-a371-2d44-f1bad6505684@gmail.com> To: Dennis Fedtke X-Mailer: Apple Mail (2.2104) X-Provags-ID: V03:K0:39REg/A9wQ8e2YJqNNtf3KYI4n97rscq1xf6TVmRtmb1TL6aatC hiwU4mjwLSFYItxBsznaLqRmin1HAv1wEscvPKPSrs9x4dYGzeQzjDHCiZnHHW4MtWVPpE/ ABWDaShCQfiYnSfddqMlJJMf5CXpW4x7nMVb86F1ajevf5vE6HV+mr2I6uberDgNPwYNjjv 4H4D/CAPOxTsDdOrKU2xg== X-UI-Out-Filterresults: notjunk:1;V01:K0:zsDbaNEKzMA=:y8cf5S8YxyrLn9VV/teWom VNHzFEBMCwZZ1NItcdLhWZyRS6+LTI3IKfGMD589ViOZmFYCCZMZ1g5neYKqk8UHshI43ESma KmMfSomCYpF2xiSTpUCPDI1ZDhM9MKVTpIFeh+49/4brfCfpLsCqF9ioTs+thX1FvcqGm1Ave 3AgxwF4rHvfKYkUazFvO8VfWe9747dSgJOHqRp6kKClSMNnCobCPRt7ujF0rgy+uUiYJreyHn WMWuG40v+TtIaXH5D8NLxud3VwP3a4bXHtIYEODSeur6yJOB0lN5BvHZvhh0MQhQvqFMd2J1J 6nAtoTFQ/kTEaSHXtBgai8x/PlEK89xgXmwbsUJSer3y2Li2PRYUpoRWAHMYPacXg6boWA9vg IJIhoMNsOZLBifvBSqsEO9BmMrtyRvgts5T1KBzUnE4CmpzONxbXmMr90lF3vCUFwPkGWpXp4 qSWxEBpW7fYbEIxceb7LOWr77WloAOU5wET8Et/HYEF60n+dkfKQyRzqfQA/3l08D/8ZPzgyZ Rn7zx80f0liWFa2GmIzii6XhMhoh0GRzweCHHeRDewH4oUXPuqrGrB1VVkMBO7gl6x1rgKq0p 9L0byTUVhpcHUiuHSguaocfn8/4SJhw7YDPnB7i0jfVNUuA3RfXG3OoN/b3Cc7HBnfF2RXF+s xTQ82h2SydbT74hvQt3oxGs7fMQWDut+bfGui6AMrmRnie4I2ZclNU54NPX4YrF74im4gMPVT X+HqxXvqcX630erlV+zZCpcEFRgTXu1lyP1IN0NETu560xyTRMHfsLKGL+HtVzcpbeGEGjY9j vgTiLR+/EyEIfYlT8gvtRXymlhAYA== Subject: Re: [Cake] New to cake. Some questions X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 Jun 2016 05:20:19 -0000 Hi Dennis, > On Jun 10, 2016, at 02:49 , Dennis Fedtke = wrote: >=20 > Hi Sebastian, >=20 > Sorry this is positive or? I would say that is unclear=E2=80=A6 > But i need more samples ? I would try with more samples, after checking that the ping = times in the recorded data file actually are larger for larger probes = than for smaller, some hosts will reply with a fixed maximum ICMP packet = instead of returning the received packet, thereby reducing the signal = range (as only the upload leg of the link is meaning fully contributing = useful differential signal. BTW I am in central europe so at times of the day my responses = can be very sporadic, as I either am at work or sleeping ;) Best Regards Sebastian >=20 > Thanks :) >=20 >=20 > Am 10.06.2016 um 01:11 schrieb moeller0: >> Hi Dennis, >>=20 >>> On Jun 10, 2016, at 00:45 , Dennis Fedtke = wrote: >>>=20 >>> Hi Sebastian, >>>=20 >>> thank you for your answers :) >>>=20 >>> The ATM overhead detector script is currently running. >>> I read the wiki about it but im not quite sure how to interpret the = plot. >>> I mean what info should i read from it? maximum packet size? >> The relevant number is reported as =E2=80=9CEstimated overhead = preceding the IP header=E2=80=9D in the top part of the second figure = created by the script. But that is only relevant.useful if you see a = nice step like plot in figure 2 as well ( the second figure in = https://github.com/moeller0/ATM_overhead_detector/wiki as positive and = the fourth figure as negative example. >>=20 >>> If yes do i set the overhead in cake? Or do i set iptables to clamp = to new mtu/mss? >> If you use plain cake and you know the numerical overhead (NN) = the easiest is to add the following to your cake invocation: =E2=80=9Catm = overhead NN=E2=80=9D >>=20 >> Please note that if you use cake on an ethernet interface the kernel = will already account for 14 byte of ethernet overhead, so if the script = told you 44 as actual overhead, you use =E2=80=9Doverhead 30=E2=80=9D to = address that. If you use a pppoe interface the kernel will most likely = not add the 14 bytes for you, so then you would use =E2=80=9Coverhead = 44=E2=80=9D (I excluded the atm option in the last examples for = clarity=E2=80=A6) >>=20 >>> Regarding UDP paket dropping problem: >>> I just read some forums and users stated that under heavy load cake = starts to drop udp packets which causes lag ingame. >>> My idea was to set ingress/egress to diffserv4 and apply the EF dscp = mark on those packets. >> Ell, not a bad idea, but often the problem are in the incoming = traffic, and unfortunately with the ifb we use we can not use iptables, = but only tc, and remarking with tc is unpleasant. >>=20 >>> Will this even work? if yes how to do this? iptables? >> No, you wuld need tp use tc. >>=20 >>> ipt -t mangle -A PREROUTING -p udp -m multiport --ports 5000:5500 -j = DSCP --set-dscp-class EF >>>=20 >>> Like thia? Is prerouting correct here? (Taken from layer cake = script) >> This will affect outgoing packets and might be a good idea in = your specific case. >>=20 >> BUT why don=E2=80=99t you try the default behaviour with specific = rules and tricks and report success or failure back to us, after all the = fastest/easiest classification is one one does not need to perform at = all. >>=20 >>>=20 >>> For the squash and wash feature. >>> Im asking because if i choose to squash in the advanced options of = sqm scripts. >>> The dscp fields/marks will be overwritten by iptables to 0 = (besteffort). (layer cake script) >>> So then it makes no sense to manually set dscp fields/marks or? (Or = even setting diffserv) >> No unfortunately on ingress cake sees the packets before = iptables, so the effective behavioral emulation of wash/squash by cake = is to set ingress cake to besteffort (basically cake ignores the dscp = field which functionally is identical to all packets having the same = value). The squashing by iptables just clears the dscp marls so that = internal networking elements like potentially wifi liknks are not = confuzed by the dscp information. >>=20 >>> Did i understand this correctly. Per rfc isps should not provide = dscp fields/marks? >> Not exactly, per RFC DSCPs are only ever valid/defined inside a = DSCP domain and your ISPs domain ends before it reaches your CPE. Since = you have no control over your ISPs markings, they can be very much not = like you want them to be (Dave That reported that his ISP re-mapped = almost 1/3 or so of packets into the CS1 background class). So it is = recomended that each DSCP domain re-mapps the code points at its entry = point, which in your case is your router=E2=80=A6 >>=20 >> Best Regards >> Sebastian >>=20 >>>=20 >>> Thank you. >>>=20 >>>=20 >>>=20 >>> Am 09.06.2016 um 23:30 schrieb moeller0: >>>> Hi Dennis, >>>>=20 >>>> let me start with a disclaimer, I am not the best information = source for cake on this mailing list, but I assume the others will chime = in if I say something questionable=E2=80=A6 >>>>=20 >>>>> On Jun 9, 2016, at 22:58 , Dennis Fedtke = wrote: >>>>>=20 >>>>> Hi >>>>>=20 >>>>> Currently im running lede + cake + sqm_scripts and i have some = questions: >>>>>=20 >>>>> 1. What is considered the =E2=80=9Coptimal" setup atm for cake? >>>> The same as without cake; really, proper per-packet-overhead = accounting is important for bandwidth shaping, especially for ATM -based = links. I would recommend to follow the method on = https://github.com/moeller0/ATM_overhead_detector to m\empirically = measure whether your link uses ATM encapsulation and what exact overhead = is in use. >>>>=20 >>>>> e.g. which cake script should i use piece or layer cake? >>>> piece_of_cake has only one tier of priority, while layer_cake = currently offers 4. Packets are put into the different priority bands = based on the content of their TOS/DSCP filed in the IP header; if this = is greek to you, I guess piece_of_cake most likely is what you are = looking for.. >>>>=20 >>>>> 2. Recently squash and wash was removed. >>>>> But the sqm scripts were not updated. In the advanced options = should i set that the dcsp marks are kept? >>>> This really is an implementation detail that has no immediate = effect if you choose piece_of_cake as typically only the bottleneck is = sensitive to DSCP based priority banding. (Typically in that if you are = unlucky your WLAN will use the DSCP marks to move packets into 4 = different priority classes, which is fine if you want that, but bad for = not sanity checked packets coming in from the wider internet (one is not = supposed to assume incoming packets have sensible dscp markings as per = RFC) that is why the wash/squash option is missed by some of us, = independent of the fact that it was a layering violation). >>>>=20 >>>>> 3. Should i use advanced options in sqm scripts and set = triple-isolate + diffserv8 ? >>>> If you understand what these options do and believe that this is = the best for your network go ahead, otherwise=E2=80=A6 The = triple-isolate option will try to be fair to host_IP addresses first and = then for each hostIP fair to each flow, but for that to do something you = will most likely want this requires that cake sees internal IP addresses = of your end-hosts. In the typical configuration with SQM on the WAN = interface of a NAT router all internal addresses are replaced with the = external IP address of the router it self and triple-isolates per host = fairness will pretty much be equal to per flow fairness (not exactly, = but in essence). So if you want to try tiple-isolate or its better = defined brothers dual-srchost and dual-dsthost you would need to = instantiate SQM on an internal interface like LAN. But then the = direction of ingress and egress from the routers perspective changes = with regards to the internet download and upload direction and you will = need to put the internet upload bandwidth into the download field of the = sqm GUI and vice versa. Also SQM on an internal interface will also = shape internal traffic over the same interface, and that often affects = traffic to and from the wifi/wlan radios to the lan switch=E2=80=A6 (I = guess you would have preferred a shorter less vague response, but such = are the constraints=E2=80=A6) >>>>=20 >>>>> 4. Is it recommend to enable diffserv on ingress? >>>> If you trust/konw/have confirmed that your upstream (ISP?) sends = you sensible and reasonable DSCP markings by all means enable diffserv = on ingress. But the default assumption should be that your upstream used = a dscp mapping that only makes sense for them and not for you. >>>>=20 >>>>> 5. Is there still the udp packet dropping problem? e.g. games that = are using udp. >>>>> If yes does it make sense to apply diffserv classes manually? How = to do this? >>>> I am not sure what you mean, but if you test this and have some = findings please report here=E2=80=A6 >>>>=20 >>>>> 6. is the autorate_ingress still under development? >>>>> This very interesting feature. especially for docsis networks. = Will it be possible to set target ping time? >>>> The last tests did indicate that this feature is not ready for = primetime at least not on typically fixed bandwidth links and I assume = docsis links are fixed enough. >>>>=20 >>>>> 6. What difference does it make to set a different rtt? >>>>> Setting lower rtt will reduce download speed i guess but will it = allow better ping times (because of lower downloadrate uh)? >>>>> What happens if rtt is set way higher? >>>> With the RTT parameter you in essence specify how much time you = give the endpoints of a flow to respond to a congestion signal (ECN = marking or packet drop) if you select this way to small you will = sacrifice bandwidth, if you set this too high you will accumulate more = latency under load. The good thing seems to be that this does not need = to be terribly precise, order of magnitude correctness seems to be = sufficient (at least in base2) >>>>=20 >>>>=20 >>>>> Thank you! >>>> I am sure the real experts will also chime in=E2=80=A6 >>>>=20 >>>> Best Regards >>>> Sebastian >>>>=20 >>>>> _______________________________________________ >>>>> Cake mailing list >>>>> Cake@lists.bufferbloat.net >>>>> https://lists.bufferbloat.net/listinfo/cake >>>=20 >>> _______________________________________________ >>> Cake mailing list >>> Cake@lists.bufferbloat.net >>> https://lists.bufferbloat.net/listinfo/cake >=20 >=20