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Re: [Astlinux-devel] Comcast/Xfinity DOCSIS 3.1
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From: Lonnie A. <li...@lo...> - 2018-09-06 13:05:25
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DOCSIS 3.1 was enabled overnight at my location, the simple "mtr" is better than before... For my COX DOCSIS 3.1 (to the default gateway address) -- gw-lan ~ # mtr -wn z.y.x.w Start: 2018-09-06T07:31:30-0500 HOST: gw-lan Loss% Snt Last Avg Best Wrst StDev 1.|-- z.y.x.w 0.0% 10 6.0 6.5 6.0 7.1 0.5 -- Hardly a definitive test, but jitter is measurably lower than before. Using iperf3 to my Linode instance, 9-hops, 31.5 ms away... gw-lan ~ # iperf3 -c host.tld -u Connecting to host host.tld, port 5201 ... - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Jitter Lost/Total Datagrams [ 5] 0.00-10.00 sec 1.25 MBytes 1.05 Mbits/sec 0.000 ms 0/906 (0%) sender [ 5] 0.00-10.03 sec 1.25 MBytes 1.05 Mbits/sec 1.324 ms 0/905 (0%) receiver gw-lan ~ # iperf3 -c host.tld -u -R Connecting to host host.tld, port 5201 Reverse mode, remote host host.tld is sending ... - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Jitter Lost/Total Datagrams [ 5] 0.00-10.03 sec 1.26 MBytes 1.05 Mbits/sec 0.000 ms 0/909 (0%) sender [ 5] 0.00-10.00 sec 1.25 MBytes 1.05 Mbits/sec 0.085 ms 0/907 (0%) receiver Using "mtr" to host.tld (my Linode instance) has a noticeably lower "StDev" than before, of course other factors can effect this, but the first hop has a noticeably lower ICMP standard deviation with DOCSIS 3.1 than before with DOCSIS 3.0. For what it is worth. Lonnie > On Aug 6, 2018, at 9:20 AM, Lonnie Abelbeck <li...@lo...> wrote: > > Should anyone make the D3.0 to D3.1 modem upgrade it would be interesting to measure any latency change. > > On the edge AstLinux box ... > > Use "ip r" to find the default "via" gateway address > > use "mtr -wn z.y.x.w" to the gateway address z.y.x.w for both D3.0 and D3.1 and compare. > > For my COX DOCSIS 3.0 > -- > gw-lan ~ # mtr -wn z.y.x.w > Start: 2018-08-06T09:14:52-0500 > HOST: gw-lan Loss% Snt Last Avg Best Wrst StDev > 1.|-- z.y.x.w 0.0% 10 8.2 9.1 6.8 19.0 3.7 > -- > > Lonnie > > > >> On Aug 6, 2018, at 8:38 AM, David Kerr <Da...@Ke...> wrote: >> >> Thanks Lonnie. I think I will wait-and-see. The modems are quite expensive right now. I am on Xfinity Blast tier which is supposed to be 250Mbps down / 10Mbps up and my speedtest shows I get ~210 down and ~12 up. I suspect that the 210 down is probably close to practical limit on my modem, although it is supposed to go faster that is probably in perfect lab-bench conditions and not real world. So it is possible a DOCSIS 3.1 modem might do me some good. >> >> On Sun, Aug 5, 2018 at 9:01 AM, Lonnie Abelbeck <li...@lo...> wrote: >> Doing some research and reaching out to "dslreports" forums, it does appear that a DOCSIS 3.1 modem (with 3.1 infrastructure) does offer more robust IP transport ... somewhat less latency and jitter. DOCSIS 3.1 uses a better error correction method, Low Density Parity Check (LDPC), which is implemented in DOCSIS 3.1 modem hardware. >> >> The question is whether it is worth upgrading now, or wait for your ISP to give you an incentive to upgrade to a DOCSIS 3.1 modem. >> >> I'll probably look at getting a DOCSIS 3.1 modem shortly after 3.1 is available in my area, keeping the same download speed plan. >> >> Lonnie >> >> >> >>> On Aug 4, 2018, at 10:04 AM, David Kerr <Da...@Ke...> wrote: >>> >>> That is exactly the question I am asking myself. Is it worth it. I can understand why the ISP would want me to upgrade (spread customer load across many more channels) but it is not at all clear why I would want to upgrade. I agree latency and jitter is more important than raw bandwidth, I have plenty of that (download at least). >>> >>> David. >>> >>> On Sat, Aug 4, 2018 at 10:56 AM, Lonnie Abelbeck <li...@lo...> wrote: >>> >>>> On Aug 4, 2018, at 9:08 AM, David Kerr <Da...@Ke...> wrote: >>>> >>>> Comcast/Xfinity have been bugging me to upgrade my cable modem for the past few months. Started with emails, now getting telephone calls, stating that my current modem cannot take advantage of their latest technology upgrades. I'm assuming they have rolled out DOCSIS 3.1 into my area. I'm not sure I am going to do it yet but looking at the options there are basically three to chose from, Netgear, Arris and Motorola. >>>> >>>> Ok, so the point of this post... the Motorola claims to support up to 2Gbps download by channel bonding two 1Gbps ethernet ports. Of course Comcast doesn't have anything like that speed support but it does prompt the question as to whether Astlinux could channel bond two ports into EXTIF. And of course it would need to also bond two ports for INTIF that would need to connect to a switch that supported bonding. >>>> >>>> Clearly not something needed anytime soon, but I am curious. >>>> >>>> Thoughts? >>>> David >>> >>> My ISP (COX) will be turning on DOCSIS 3.1 any day now in my area, I'm not interested in DOCSIS 3.1's 1 Gbps down (only 30-ish Mbps up). Currently I have a 50/10 Mbps business connection and other than running speed tests I can't think of a time I noticed where the complete data path was limited by 50 Mbps. Over time this will slowly change and then 100 Mbps may be useful. >>> >>> Personally, the quality of the connection ... low latency, low jitter, low downtime is far more important to me than down speed greater then 100 Mbps. >>> >>> So, how does a DOCSIS 3.1 modem perform (latency and jitter) on DOCSIS 3.1 infrastructure compare to a 3.0 modem on the same 3.1 infrastructure ? I have yet to find an answer to that question. >>> >>> Also beware that some DOCSIS 3.1 modems use an Intel Puma 6 chipset with a lot of problems. >>> >>> Also beware COX residential (and Comcast I think) currently have a default 1 TB data tier, so at 1 Gbps 1 TB of traffic occurs in 133 minutes. >>> >>> So David, I don't think ethernet bonding is worth worrying about. :-) 10 Gbps NIC's will probably be ubiquitous when we need such a thing. >>> >>> But, since a DOCSIS 3.1 modem will aggregate a lot more channels than a DOCSIS 3.0 modem (on 3.1 infrastructure) would a DOCSIS 3.1 modem be a useful upgrade for a plan speed of 50-300 Mbps ? >>> >>> Lonnie > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Astlinux-devel mailing list > Ast...@li... > https://lists.sourceforge.net/lists/listinfo/astlinux-devel > > |
