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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt'>Rebooting the modem is probably a good idea.<br><br>I used to have regular issues with Comcast “slowness” but they always told me they saw no such issue from their end. Rebooting the modem is something I do these days at home and I haven’t seen those issues in a long time. (Of course, they do still go down on rare occasion but that is a problem with most ISPs.) At my former job we’d lose AT&T less often than Comcast Business. Rebooting the cable modem there (which looked suspiciously like the one in my home) sometimes resolved issues. We did NOT do that daily. <br><br><br><o:p></o:p></span></p><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> Ale <ale-bounces@ale.org> <b>On Behalf Of </b>Jason Jessico via Ale<br><b>Sent:</b> Thursday, November 14, 2024 11:53 AM<br><b>To:</b> Atlanta Linux Enthusiasts <ale@ale.org><br><b>Cc:</b> Jason Jessico <jjessico@gmail.com>; Derek Atkins <derek@ihtfp.com><br><b>Subject:</b> Re: [ale] Slightly OT: Reasonable Latency with Comcast Business<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>You may also find it helpful to have something specific to check for DNS resolution. In some systems/cases the failure to resolve an FQDN used as part of the check will show up as a generic "no/lost connection". Provided the system has the capability a set of hosts to test to could be something like localhost, the LAN default gateway, the modem's default gateway, the FQDN the system uses by default for testing, and a well known IPv4 endpoint like Google's 8.8.8.8.<o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Thu, Nov 14, 2024 at 11:25<span style='font-family:"Arial",sans-serif'> </span>AM Derek Atkins via Ale <<a href="mailto:ale@ale.org">ale@ale.org</a>> wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><p class=MsoNormal>What concerns me is the "empty" part of your graph.. At the 45ms peak,<br>there appears to be a section of "no response". Note that depending on<br>the service being used, it's possible that the service is down.<br><br>FWIW, I run mrtg to monitor my network -- I run pings to several different<br>places to test latency across my uplink. Specifically, one place I ping<br>is my 1st-hop upstream router. If that router goes down or doesn't<br>respond, it is 100% correlated to my connection being down for everything.<br><br>Of course, YMMV.<br><br>-derek<br><br>On Thu, November 14, 2024 11:08 am, Neal Rhodes via Ale wrote:<br>> Thanks for the reply.<br>><br>> I just got off the phone with Comcast. To my delight it only took 12<br>> minutes total.<br>><br>> Their criteria is, they don't get concerned until:<br>><br>> * Packets get lost;<br>> * Latency exceeds 100ms.<br>><br>> To which I can only say, wow.<br>><br>> Comcast tech also says I should reboot their router. (uptime over 140<br>> days.)<br>><br>> My bet is the Ubiquiti router has much tighter assumptions. Next I<br>> need to ask them precisely what their criteria is for concluding<br>> disconnection.<br>><br>> regards,<br>><br>> Neal<br>><br>> On 2024-11-14 10:56, Derek Atkins wrote:<br>><br>>> Hi Neal,<br>>><br>>> I ditto what James says (and was going to say the same thing). Take a<br>>> laptop that you KNOW can handle 1Gb, to be sure it's not a laptop<br>>> limitation, and then plug into the router to be sure you can show the<br>>> issue from their CPE. Showing it from the Ubiquiti equipment is not<br>>> sufficient.<br>>><br>>> Also, it helps if you can have a tech on the phone while the problem is<br>>> occurring. I used to have Comcast Biz and would lose network every<br>>> time<br>>> there was a neighborhood power outage. It took a 3hr outage during the<br>>> day and me calling just as the outage stopped for them to find the node<br>>> with the bad battery.<br>>><br>>> So back to your issue. It looks like it could be a network drop, a<br>>> DHCP<br>>> renew that takes too long, or possibly even an upstream issue with<br>>> Comcast.<br>>><br>>> Expect to spend time trying to reproduce it, especially if it's<br>>> something<br>>> that isn't reliably reproducible. You might also want to look at<br>>> potential buffer bloat, and also explore the possibility of NAT Table<br>>> overload.<br>>><br>>> Having said that, the RTT you see (17ms) is reasonable for a cablemodem<br>>> plant.<br>>><br>>> -derek<br>>><br>>> On Thu, November 14, 2024 10:41 am, James Taylor via Ale wrote: My<br>>> experience with Comcast Business says that the you need to spend time<br>>> in the furnace room.<br>>> They are going to test from their router and if you don't show the<br>>> problem<br>>> there, they are unlikely (i.e. - never) to look further.<br>>> -jt<br>>><br>>> James Taylor<br>>> 678-697-9420<br>>> <a href="mailto:james.taylor@eastcobbgroup.com" target="_blank">james.taylor@eastcobbgroup.com</a><br>>><br>>> Neal Rhodes via Ale <<a href="mailto:ale@ale.org" target="_blank">ale@ale.org</a>> 11/14/2024, 10:36 AM >>><br>> This feels like a classic three party finger pointing exercise, and I'm<br>> doing a bit of research before we jump in.<br>><br>> A couple of years ago, our church put in a sophisticated (at least by MY<br>> Measure) Ubiquity Unifi Mesh network, mostly to support security camera<br>> for the community pre-school.<br>><br>> The core is a UDM Pro router, feeding all Ubiquiti stuff.<br>><br>> And it has run totally steady.<br>><br>> Here's the rub: Now that the "Last Guy That Touched it" moved to<br>> Florida, I'm getting multiple alerts per day to the effect of:<br>><br>> * Your primary internet Comcast Business was disconnected and has been<br>> restored multiple times in last 24h. If this persists, please try<br>> restarting your ISP Modem.<br>> * Primary internet is experiencing high latency. Please restart the<br>> modem or contact the ISP if this persists.<br>><br>> Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaand, nobody complains. Occasionally,<br>> I will see Zoom meetings from home where the church participants go<br>> really fuzzy and blocky, like Zoom has downshifted their resolution.<br>><br>> Apparently it measures ping time to <a href="http://Ping.UI.Com" target="_blank">Ping.UI.Com</a> to decide this.<br>><br>> The Unifi Console reports the Comcast Business router as providing<br>> typical 14ms latency. With the occasional spike to 45ms.<br>><br>> When I ping that address from my Uverse internet from home, I'm seeing<br>> consistently results from 7ms to 10ms.<br>><br>> I don't know whether to ask Ubiquiti about raising their thresholds, or<br>> Nag Comcast about their performance. I guess I could ask Ubiquiti<br>> precisely what does "Internet Disconnected" mean?<br>><br>> My personal experience with Business Comcast in the past has been.......<br>> not impressive. Usually, a service call just makes it worse. Is<br>> Comcast going to take my report from Ubiquiti seriously? Or tell me to<br>> pound sand? What additional evidence need I present?<br>><br>> Yes, I could spend a quality hour in the furnace room, with a notebook<br>> connected to the LAN side of the Comcast router, (the only way I can<br>> talk to it) and see what I can see.<br>><br>> I suppose I could just call Comcast, and give up another hour of my life<br>> to try and talk to someone with a clue.<br>><br>> regards,<br>><br>> Neal<br>> _______________________________________________<br>> Ale mailing list<br>> <a href="mailto:Ale@ale.org" target="_blank">Ale@ale.org</a><br>> <a href="https://mail.ale.org/mailman/listinfo/ale" target="_blank">https://mail.ale.org/mailman/listinfo/ale</a><br>> See JOBS, ANNOUNCE and SCHOOLS lists at<br>> <a href="http://mail.ale.org/mailman/listinfo_______________________________________________" target="_blank">http://mail.ale.org/mailman/listinfo_______________________________________________</a><br>> Ale mailing list<br>> <a href="mailto:Ale@ale.org" target="_blank">Ale@ale.org</a><br>> <a href="https://mail.ale.org/mailman/listinfo/ale" target="_blank">https://mail.ale.org/mailman/listinfo/ale</a><br>> See JOBS, ANNOUNCE and SCHOOLS lists at<br>> <a href="http://mail.ale.org/mailman/listinfo" target="_blank">http://mail.ale.org/mailman/listinfo</a><br>><br><br><br>-- <br> Derek Atkins 617-623-3745<br> <a href="mailto:derek@ihtfp.com" target="_blank">derek@ihtfp.com</a> <a href="http://www.ihtfp.com" target="_blank">www.ihtfp.com</a><br> Computer and Internet Security Consultant<br><br>_______________________________________________<br>Ale mailing list<br><a href="mailto:Ale@ale.org" target="_blank">Ale@ale.org</a><br><a href="https://mail.ale.org/mailman/listinfo/ale" target="_blank">https://mail.ale.org/mailman/listinfo/ale</a><br>See JOBS, ANNOUNCE and SCHOOLS lists at<br><a href="http://mail.ale.org/mailman/listinfo" target="_blank">http://mail.ale.org/mailman/listinfo</a><o:p></o:p></p></blockquote></div></div></body></html>