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T3/T4 Timeouts during Typical Work Hours

MorrisDMorrisD Posts: 8 ✭✭✭
in Connectivity Sep 09, 2020

Hello all,

I've recently set up a Netgear CAX80 router/modem combo in my home. It's great when it works but over the last few days I've been getting a ton of T3/T4 timeouts between the hours of 9:30am to as late as 6:30pm (EST), as well as the occasional hiccup during the night or so. It's been fine this morning (so far) but it's still concerning as someone who works from home.

I've had about three techs come out. One removed a splitter, the other replaced the line from my house to the nearby pole, and the most recent confirmed that the router was configured with the correct code on their end (?) and that the cable line was direct, albeit lengthy.

I'd like to avoid another tech visit, or at least have some sort of understanding about what's going on in the event they inevitably have to return, so if anyone could take a look at these connection numbers/error logs and narrow down the problem, that would be greatly appreciated!

(Example of the error logs):


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Comments

  • misterjmisterj Posts: 80 ✭✭✭✭
    Sep 09, 2020

    MorrisD, I would like to see the same screenshots immediately after a power cycle. Where are you located? It looks like to me you have a DOCSIS 3.0 and 3.1 connection simultaneously. I have seen this before and suspect it is the problem. Thanks and enjoy, John.

  • MorrisDMorrisD Posts: 8 ✭✭✭
    Sep 09, 2020

    misterj,

    I'm located in Columbia, South Carolina, if that's what you were referring to by location.

    In the event that it is a DOCSIS 3.0 and 3.1 simultaneous connection, how could I remedy that?

    Here are the screenshots after the reboot:

    Not sure if you need the error logs but here are some that displayed as the device came back online, caught a few hiccups:


  • misterjmisterj Posts: 80 ✭✭✭✭
    Sep 09, 2020

    Thanks, MorrisD. Looks identical to your first one. I assume it is as bad as before? I am new to DOCSIS 3.1, OFDM and OFDMA, so some guessing going on. I have thought of nothing you can do about this - Spectrum will need to correct it. I do know that when running in OFDM and there are lots of errors that the modem will switch to QAM only - essentially DOSIS 3.1 to 3.0. It looks like to me that your modem has switched but kept OFDM. This will use up twice as much bandwidth 384 MHz vs 192 MHz for the downstream. According to your screenshots you have 384MHz of DS bandwidth locked. I suspect Spectrum is not provisioning your modem correctly leaving 3.0 and 3.1 running at the same time. I talked to an Arris (also make DOCSIS 3.1 Modem-SB8200) tech about this and was told that there should not be two connections (3.0 and 3.1) at once. The only remedy I can suggest is for you to present your screenshots to a higher level Spectrum support tech. When IPv6 first came out I could not figure out how to configure my Router, so I call Support and immediately asked for Level 2 and was switched right then. When that person could not answer my question, I was switched to even higher and I finally found a person who said they would get the answer and get back to me. In a couple of days I had IPv6 working. Please keep us informed and I hope you are able to get a good response. Thanks and enjoy, John.

  • MorrisDMorrisD Posts: 8 ✭✭✭
    Sep 09, 2020

    misterj,

    Thanks for your responses. I will see if I can talk to a support technician and see if they can figure out the issue. Will update whenever I make some progress.

  • RAIST5150RAIST5150 Posts: 794 ✭✭✭✭
    edited September 9 Sep 09, 2020

    @MorrisD

    There appears to be issues with the upstream channels?

    "RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW", ranging 37-41 in the same capture, etc.

    As low as they are in your captures (a rise across all 4 to 43-48 mid day is more the norm in many of Spectrum's markets), they may be getting overdriven upstream from the modem, and something like noise or some sort of intermittent connection is triggering spikes outside of the modem's or CMTS limits.

    They need to conduct a closer inspection both locally and upstream to get the quality of upstream signal back in check again. Then they can look into what is up with the downstream interference on the 3.1 downstream channel. The modem and head end appear to be following the "mixed mode" 3.0/3.1 specifications and are electing to use the 3.0 channels though, so that may be fine for the time being--resolving upstream is likely the bigger issue atm, as you seem to have specific error messages pointing to them.

  • MorrisDMorrisD Posts: 8 ✭✭✭
    Sep 09, 2020

    RAIST5150,

    Thanks for your feedback - I got off the phone with a Support rep not too long ago - didn't know anything about the error log messages beyond T3/T4 timeouts and I didn't press the issue - they'll be sending another technician to inspect the premises. Fingers crossed.

  • misterjmisterj Posts: 80 ✭✭✭✭
    Sep 09, 2020

    MorrisD, I would suggest you print out your screenshots and show them to the tech and let them read my rant. Enjoy, John.

  • MorrisDMorrisD Posts: 8 ✭✭✭
    Sep 09, 2020

    misterj,

    I'll definitely refer to this post in my initial explanation when the tech arrives!

  • misterjmisterj Posts: 80 ✭✭✭✭
    Sep 09, 2020

    Thanks, MorrisD. I see you have the 'Enable Extended Upstream Transmit Power' checked. Please uncheck this and post the results. Thanks and enjoy, John.

  • MorrisDMorrisD Posts: 8 ✭✭✭
    Sep 09, 2020

    misterj,

    Huh. I thought that feature was more helpful than not. Granted, this is around the time everything would mellow out with my connection, but I will monitor for any error messages as the night continues.

    Here are the logs after the reboot:

    I only got a few messages in the error log after reboot, probably not necessary:


  • RAIST5150RAIST5150 Posts: 794 ✭✭✭✭
    edited September 9 Sep 09, 2020

    @MorrisD

    Extended Upstream Power option should be set by the system admins... it can actually be toggled by the modem config file even.

    It is hard to say yea or nay on the setting without knowing how they are establishing the limits of the range. If they are still going with the Arris standard that has been a general guideline for years (51 phi, 12 db range, 6db across a channel group), then it would appear you may need the ~3db boost it allows.

    It all depends on whether they are still rolling with previous standards from the 3.0 era for these particular channels, or adopting new guidelines for those channels as they pull in the 3.1 channels. Here in Florence (your "sister" market), they seem to still be running with that Arris 3.0 guideline.

    This is something best left for them to assign according to their policies. If you see it come back on after a reset--leave it alone unless SPECTRUM tells you or does otherwise.

  • misterjmisterj Posts: 80 ✭✭✭✭
    Sep 09, 2020

    Thanks, MorrisD. Certainly looks better right now! Enjoy, John.

  • MorrisDMorrisD Posts: 8 ✭✭✭
    edited September 10 Sep 10, 2020

    ***Update:***

    Once the tech came out for the visit, they decided to replace the cable running under my home. Apparently, the cable was badly damaged, as if chewed through by a rat or something. I am not sure why it required 4 tech visits to notice something so obvious (the tech showed me a picture - it wasn't pretty), but it did. I suppose I could've taken a look myself, but the crawl space was small and with various other cables strewn around from previous work and electrical units blocking my path I couldn't make heads or tails of where to go.

    All in all, the levels seem good now and no timeouts - will update if another issue arises.

  • misterjmisterj Posts: 80 ✭✭✭✭
    Sep 11, 2020

    Thanks, MorrisD. In a couple of days please post a levels screenshot. Thanks and enjoy, John.

  • MorrisDMorrisD Posts: 8 ✭✭✭
    Sep 22, 2020

    ***Update #2:***

    The cable wasn't the issue (at least not completely). It took a little bit to get another tech, but today I had one (along with the field supervisor, to my surprise) to come out during the drop window. Forgive me for my lack of knowledge on the subject, but I believe what they said was that out of the four ports connecting my various neighbors on the nearby pole, mine specifically was the only one experiencing intermittent issues. They swapped me to a different port and voila - no drops (at least in the 5-10ish minutes it took me to type this post.)

    I guess eventually someone will come out with a bucket truck and make the fix but hopefully this solves everything.


    Here are the current levels. To my understanding the downstream might be a tad high, but I have a few attenuators I bought during the troubleshooting process that could tweak the levels if need be.


  • RAIST5150RAIST5150 Posts: 794 ✭✭✭✭
    edited September 22 Sep 22, 2020

    @MorrisD

    Sounds like an old unit in the pedestal. Have a similar problem here... only 4 good ports left on it.

    Likely won't get it replaced until either another port craps out, or we finally get the bump to 200mbps in our neighborhood, since our building is actually serviceable by two distribution points.

    Don't attenuate the line anytime soon. Downstream values in general are in ranges they strive for, and will shift a bit when the winter weather comes in. Gains will adjust at that point to compensate a bit. If you pad things yourself before those tweaks take place, it may mask underlying issues.

    Now they are aware their equipment is at fault, so let them come out and adjust/replace accordingly.

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