Forum Discussion

Peterockinit's avatar
Peterockinit
New Contributor III
5 years ago

Dynamic range window violation

I keep getting this on my brand new (2 weeks old) sb8200 modem:

Dynamic Range Window violation

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW

I have had 6 technicians out here. I have replaced my modem, my router, all my wiring (coax from dmark to modem and Ethernet with new cat6), cox put in a new drop from street to my house, have had all sorts of different attenuators for diff power levels. 

I saw several people post the same problem as me but there was never a solution. Can someone please help.

37 Locked QAM256 381000000 Hz 2.2 dBmV 40.0 dB 0 0
1 Locked QAM256 783000000 Hz -1.0 dBmV 39.9 dB 0 0
2 Locked QAM256 789000000 Hz -1.1 dBmV 39.8 dB 0 0
3 Locked QAM256 795000000 Hz -1.3 dBmV 39.8 dB 0 0
4 Locked QAM256 801000000 Hz -1.4 dBmV 39.8 dB 0 0
5 Locked QAM256 807000000 Hz -1.2 dBmV 40.0 dB 0 0
6 Locked QAM256 813000000 Hz -1.6 dBmV 39.8 dB 0 0
7 Locked QAM256 819000000 Hz -1.7 dBmV 39.9 dB 0 0
8 Locked QAM256 825000000 Hz -2.2 dBmV 39.5 dB 0 0
9 Locked QAM256 831000000 Hz -2.4 dBmV 39.5 dB 0 0
10 Locked QAM256 837000000 Hz -2.6 dBmV 39.4 dB 0 0
11 Locked QAM256 843000000 Hz -2.7 dBmV 39.5 dB 0 0
12 Locked QAM256 849000000 Hz -2.8 dBmV 39.5 dB 0 0
13 Locked QAM256 855000000 Hz -3.1 dBmV 39.1 dB 0 0
14 Locked QAM256 861000000 Hz -3.5 dBmV 39.1 dB 0 0
15 Locked QAM256 867000000 Hz -3.4 dBmV 38.9 dB 1 0
16 Locked QAM256 873000000 Hz -3.3 dBmV 39.2 dB 0 0
33 Locked QAM256 357000000 Hz 2.3 dBmV 39.8 dB 0 0
34 Locked QAM256 363000000 Hz 2.2 dBmV 39.8 dB 0 0
35 Locked QAM256 369000000 Hz 2.2 dBmV 39.9 dB 0 0
36 Locked QAM256 375000000 Hz 2.1 dBmV 40.0 dB 0 0
38 Locked QAM256 387000000 Hz 2.1 dBmV 40.1 dB 0 0
39 Locked QAM256 393000000 Hz 2.2 dBmV 40.1 dB 0 0
40 Locked QAM256 399000000 Hz 0.5 dBmV 39.6 dB 0 0
41 Locked QAM256 405000000 Hz 1.1 dBmV 39.9 dB 0 0
42 Locked QAM256 411000000 Hz 1.5 dBmV 39.9 dB 0 0
43 Locked QAM256 417000000 Hz 1.4 dBmV 40.0 dB 0 0
44 Locked QAM256 423000000 Hz 1.5 dBmV 39.9 dB 0 0
45 Locked QAM256 429000000 Hz 1.6 dBmV 39.9 dB 0 0
46 Locked QAM256 435000000 Hz 1.8 dBmV 39.9 dB 0 0
47 Locked QAM256 441000000 Hz 1.8 dBmV 40.1 dB 0 0
48 Locked QAM256 447000000 Hz 2.1 dBmV 40.1 dB 0 0
159 Locked Other 300000000 Hz 5.9 dBmV 41.2 dB 3854710679 0




Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 4 Locked SC-QAM Upstream 16900000 Hz 6400000 Hz 49.0 dBmV
2 1 Locked SC-QAM Upstream 36300000 Hz 6400000 Hz 51.0 dBmV
3 2 Locked SC-QAM Upstream 29900000 Hz 6400000 Hz 51.0 dBmV
4 3 Locked SC-QAM Upstream 23500000 Hz 6400000 Hz 50.0 dBmV
  • Dammitjim's avatar
    Dammitjim
    New Contributor II
    5 years ago

    I'm having this same issue also, almost exactly. I posted about it in these forums and they said they'd need to do some research on my exact situation, and eventually got back to me saying "there's a known escalated issue for your area that we hope to resolve in the coming weeks" and no further information on it; they can't attach my name to the ticket, they can't discount my service because it's barely useable, they can't give me updates as they occur, and of course they have no timeline for resolution.

    At least I haven't had to replace hardware and lines and pay for several technicians to come out. This is f*****g ridiculous.

  • Allan's avatar
    Allan
    Moderator
    5 years ago
    Hello. Do you have any signal amps or splitters on the line going to the modem? -Allan, Cox Support Forums Moderator.
    • Peterockinit's avatar
      Peterockinit
      New Contributor III
      5 years ago

      Hi thanks for the reply.

      Just one splitter at the demarc on the attenuator is on the line, which all were installed recently by different technicians over the last two weeks. The rest of my coax is a home run from my demarc to my modem.

      After yesterday's technician visit and the addition of new attenuators, I am still receiving the dynamic range window violations, but in addition now I'm getting t3 timeouts... 😵

      • SharonL's avatar
        SharonL
        Former Moderator
        5 years ago
        Hello,

        Thank you for reaching out to the Social Media Team. This appears as if you may need someone to investigate your account personally. We would be able to assist you with this. Please reach us on Twitter at @CoxHelp, visit us on Facebook, or email us at cox.help@cox.com. Provide us the name on the account with the complete service address with a link to this thread so we can get started.

        Thank you.

        Sharon
        Cox Support Forum Moderator

  • Peterockinit's avatar
    Peterockinit
    New Contributor III
    5 years ago

    Replaced my modem again. Still don't know why I am getting these dynamic range window violation errors.

    So far:

    3 new modems

    New router

    New coax from demarc to modem

    New splitter from cox

    New drop from street to demarc

    After 8 tech visits, everything looks "fine". My internet is have intermittent disconnects and am still getting dynamic range window violations which cause thousands of uncorrectables on my channels

  • Peterockinit's avatar
    Peterockinit
    New Contributor III
    5 years ago

    Replaced my modem again. Still don't know why I am getting these dynamic range window violation errors.

    So far:

    3 new modems

    New router

    New coax from demarc to modem

    New splitter from cox

    New drop from street to demarc

    After 8 tech visits, everything looks "fine". My internet is have intermittent disconnects and am still getting dynamic range window violations which cause thousands of uncorrectables on my channels

    • Dave9's avatar
      Dave9
      Contributor III
      5 years ago

      Dynamic Range Window violations won't directly cause uncorrectable errors on your channels, but an overall problem might cause both DRW violations and uncorrectable errors. Uncorrectable errors are a downstream data transmission issue.

      A dynamic range window violation is an upstream problem that happens when your modem sends a ranging request and then gets back a power level request for a channel is more than 12 dBmV above the lowest power level in the upstream channel set.

      Basically, at least 2 times per minute, your modem asks the Cox system "how loudly should I transmit on each channel?" If Cox comes back with numbers like 45, 44, 43, 41 then that's all good. But if it comes back and asks for numbers like 38, 36, 52, 39 that would be a dynamic range window violation because the highest value (52) is more than 12 above the lowest value (36).

      I've tried to get someone to give me more information but so far I've had to learn all of this on my own while trying to troubleshoot my own problems. I don't know how bad a DRW violation is overall but it does seem like upstream data like video calls will glitch momentarily when a DRW violation happens. I think the DRW violation itself is probably caused by a momentary spike of noise on one of the upstream channels. Like I said I don't know this for sure but this makes sense based on what I've been learning.

      When my connection was working well I would get two or three DRW violations per week at most. Then when my connection started to go bad, I was getting up to 40 DRW violations per hour. Now I'm getting T3 timeouts which is a more serious type of upstream issue that causes a complete interruption of data for a short time.

      No one has been able to provide any real information about how serious DRW violations are, but I think of them as an early warning of problems that are going to get worse later.

      I'll also say that two of your channels are at the highest recommended power level for 4 bonded channels (51 dBmv). Even though that's technically within spec, it leaves no room for error. Any little thing is going to send the power level above the recommended range. It's hard to get techs to understand that because they only look at the raw number, but that high of an upstream power seems like a developing problem. Some techs will also quote the highest power for a single channel which is 61 dBmV but if you're only using one channel you aren't getting your full upload speed so for the real modern world 51 dBmV is the maximum.

      • Peterockinit's avatar
        Peterockinit
        New Contributor III
        5 years ago

        Thank you for the reply and info. The upstream channel power levels were 38 before, I called Arris and they recommended 47-51 so the tech added attenuators to reach. It didn't matter, I got the DRW still. 

        I just assumed that the drw was causing the uncorrectables because everytime I checked my modem (hourly), I would see a new DRW error and more uncorrectables stacked up also.

        A new issue has developed now. My modem login (192.168.100.1) keeps locking me out, site says location can't be reached. It happens daily. The only way I know how to bring it back is to power cycle my modem BUT this clears my logs and I can't see if I am getting DRW errors now. What the hell????

    • Allan's avatar
      Allan
      Moderator
      5 years ago
      @Peterrockinit, The modem was recently reset about 5 hours ago and I am not seeing any errors now. Are you currently experiencing any issues with the internet service? -Allan, Cox Support Forums Moderator
  • Tradev's avatar
    Tradev
    New Contributor
    5 years ago

    I have been experiencing the same issue, went and both two new modems and routers all doing the same thing so issue isn’t on my end. Did anyone find a solution? 

    • Dave9's avatar
      Dave9
      Contributor III
      5 years ago

      How often are you seeing this message? If you're seeing it a few times a week it's harmless. Every cable network is going to get a momentary glitch every now and then. If you're seeing it several times per hour you probably need Cox to check for intermittent noise on the line.

      • Tradev's avatar
        Tradev
        New Contributor
        5 years ago

        As it as often as every 30 mins and experience packet loss at all times or lag spikes. At this point it’s pretty much unusable especially at night time. 

  • Peterockinit's avatar
    Peterockinit
    New Contributor III
    5 years ago

    Is there ANYONE at Cox that understands this? What is causing this dynamic range window violation?

    • Dave9's avatar
      Dave9
      Contributor III
      5 years ago

      I also wish that we could get some details from Cox, but it seems like they prefer not to go into technical details on the forum. That leaves us to figure things out on our own. I wonder if these DRW violations are even important in DOCSIS 3.1. Take a look at this information:

      8.3.3 Dynamic Range Window
      The Dynamic Range Window defines a 12dB range of Transmit Power Levels for the CM to use for each of the channels in its Transmit Channel Set. The DRW is controlled by the CMTS and communicated to the CM in the RNG-RSP or in the TCC encodings of the REG-RSP-MP or the DBC-REQ message.

      8.3.3.1 Dynamic Range Window When Operating with a DOCSIS 3.1 CMTS
      The top of the DRW is defined as P1.6hi – P1.6load_min_set [DOCSIS PHYv3.1]. The CMTS manages the Dynamic Range Window for the modem, ensuring that the CM is not ranged at a value that would result in a violation of the Dynamic Range Window. If the CMTS commands the modem to use a transmit power level P1.6r_n, that would result in a violation of the Dynamic Range Window, the CM performs the commanded adjustment and indicates an error in the Bit 15 or 14 of the SID field of the RNG-REQ Messages.

      8.3.3.2 Dynamic Range Window When Operating With a DOCSIS 3.0 CMTS
      The top of the DRW is defined as Phi - Pload_min_set [DOCSIS PHYv3.0]. The CMTS manages the Dynamic Range Window for the modem. If the CMTS commands the modem to do something which would result in a violation of the Dynamic Range Window, the CM will reject or ignore the command.

      In other words, under DOCSIS 3.0, a DRW violation would actually cause the cable modem to reject the ranging response and who knows what kind of problem that might cause. But with DOCSIS 3.1 the modem makes the adjustment anyway and then sends an information message back to the CMTS. But since it made the adjustment maybe there's no harm done.

      In terms of what causes this message in the first place, my guess is a spike of upstream noise. But maybe it's not even that. Maybe it's completely harmless. In any case the DRW violation doesn't prevent the modem from doing what it's been requested to do. So maybe it doesn't matter at all.

      • Peterockinit's avatar
        Peterockinit
        New Contributor III
        5 years ago

        That's interesting! And I agree. We are ignored because it can't be fixed with a simple reboot. 

        I don't even know if the dynamic range window is what is causing my issues. But either way my issues are not being fixed. I have thousands of uncorrectables within a day of a fresh reboot and I get intermittent disconnects and gaming is impossible because of the lag and freezing which I assume is from packet loss.

        $170 per month for internet and this is what we get. No idea how this monopoly is allowed. It's either crappy"hi speed internet" from cox or 3mbps DSL from CenturyLink

  • Sheepdog_Mama's avatar
    Sheepdog_Mama
    New Contributor
    5 years ago

    I have had zero Internet issues for years and have been a Cox Customer since forever!  I too have the Arris 8200 cable modem, and it's been installed, reliable, and trouble free for several years.   However, this past week, the Internet has been going up and down like a yo-yo, losing Internet service multiple times per day causing havoc for us working at home.  I have Arris event logs that have "Dynamic Range Window Violation" errors all down the page.  I have just one channel that is listed below the recommended upstream power (44 instead of 45).   Cox has sent signals to reset everything at least twice, and we are still having the problem.  They are coming out on Friday.  If the problem gets fixed on Friday, I will let you know what they discovered.

    Someone else with a similar problem suggested that I request a "data technician"--he had the same problem for months until a "data tech" looked at the problem....I'm tired of being a tech support rep.