This might be a short one tonight, but I will try to include as much information as I can. Consider this an open support ticket for myself in the future.
I’ve had intermittent internet connection issues at home for the past couple of months. About once or twice a week, my cable modem (an Arris Surfboard G36 that I own, not one I rent from Xfinity) will lose connection. The logs on the cable modem are essentially useless; there’s never anything in them, let alone anything that might point to a problem. Since the problem is at the modem, it affects everything else downstream on my network, wired or wireless.
I’ve seen this issue before and it led to me replacing the previous cable modem with this one, a relatively expensive piece of small-business kit. (Edited to add: this Arris Surfboard G36 was purchased on 19 April 2022 – Brian) I’ve kept a log of the dropouts in case I have to contact Xfinity support, but I’m trying to collect more information before beating my head against the wall with their support. The few times I’ve contacted them, I get a chatbot that tells me to reboot the modem. Because the dropouts clear themselves up if I just wait it out for 10-15 minutes, I can’t tell if rebooting just occupies the time necessary for the problem to resolve on its own. I need more information.
The cable modem does have some diagnostic tools: basic shit like ping and traceroute, and a DOCSIS spectrum analyzer. My problem is, I don’t know how to read the results of the spectrum analyzer. I don’t know what’s within spec. The cable modem also reports a lot of information about the different up- and downstream channels: frequency, power level (in dB), signal-to-noise ratio, lock status. Again, despite my trying to find out what all this means and what the numbers should be, I haven’t been able to self-tutor enough to sort it out. Of course, Xfinity’s support articles are incredibly basic, aimed at non-tech consumers, so they don’t publish or bury the information I’m looking for.
I did find, during today’s troubleshooting, that a coax cable signal tester is incredibly cheap; $20. That might help me figure out if there’s something wrong with the wiring in my building (I rent so I inherited whatever is already in the walls.) Maybe there’s a slightly-more-expensive one that will give more information than just yes-signal/no-signal.
Edited to add: My problems did settle down a bit after the last factory reset I did on the modem, which by my records was on 6 March 2024, which feels relatively recent enough that I’m loathe to try it again.
Today’s outage, though, turned out not to be anything to do with my cable modem or Xfinity. In doing science, a flaw, a human flaw, is only reporting positive results. Gotta report all results in order to figure out what’s going on. What I’m saying is that today’s outage was my own damned fault. I was confuzzled because only my own desktop computer was showing any connection issues and slowness. Every other device on my network was fine. I’ll jump to the end: I had forgotten that my desktop computer was using a Proton VPN connection and it was eating up my bandwidth, disconnecting from time to time, and causing a whole lotta latency, which did not affect any other network device. Mea culpa!
I have a small audience here; if anyone has any suggestions for troubleshooting a cable modem connection issue, I am all ears. Reply or send me a note, I’d love to hear from you!