Since the new firmware update of V3.01.02 that was pushed out to Comcast I have been receiving "RNG-RSP CCAP Commanded Power in Excess of 6db Below the Value Correstponding to the Top of the DRW" errors constantly. After so many, it will start throwing T3 and T4 timeouts and go into a reboot cycle until it is happy again. Sometimes it will come back and be fine for an hour or 2, sometimes it comes back and only has one upload channel, other times I have to go, manually shut it off, and turn it on again. I have called comcast and been dealing with them for 2 weeks now. They sent someone out, he said the signal couldnt be any more perfect which I believe because this issue didnt happen until AFTER the new firmware. In talking to the person from comcast I have been talking to, she stated there has been only one other person with the same issues as me that has talked to her. She doesnt know if anyone else has called in and talked to other people. She has also been talking to co-workers to try and figure out things to try. As of right now, the last thing we thought of would be to post here. This issue has made it to the point I cant use my home network for internet and I have been using my cellphone's 4G to get things done.

Whooooa! All 3 upstream channels are at 50db. THAT my friend is your issue. CM is your Cable Modem. CMTS is the Cable Modem Termination System at the Cable Company. Your modem is SCREAMING to be heard by the CMTS. The normal range is 30db to 45db. You must have wiggle room. When your modem cannot be heard, it reboots.

Final Update: I wanted to provide a fair and acurate picture of what turned out to be causing my constant T3/T4 timeouts & the out of range errors in the CM1000 log. Whether the recent firmware update did or didn't increase the power level for some users, I do not know. But I didn't want to leave my contribution to this thread hanging with the impression that my issues were caused by a CM1000 firmware update. In fact, the unit was just reporting the true state of the signal it was receiving, and correctly timing out when that signal degraded so low that it could not hold sync. A while back, I had suspected that my splitters and/or the original house cabling (circa 1998) might be the cultprit. So I replaced my splitters with properly rated (supposedly) higher quality ones. Saw little if any change. I even removed extra splitter down to just one and used termination caps on unused ends. So I called out a Comcast tech who checked and replaced the cable line coming from the street to my house. While his external signal levels were much improved, I still had intermittent issues getting a good quality signal inside. Even after purchasing all new networking gear (Netgear CM1000 and Orbi RBK53 Router & 2 Sats), I was still having issues. So I knew something was still very wrong after continuing to see frequent T3/4 timeouts and out of range warnings, which a reset would only remedy for a short time. So I decided to connect the cable line from the street directly into my CM1000 router and observe the status and signal levels myself. Sure enough, it immediately went from reporting terrible Power and so-so SNR levels to showing much improved numbers across all 24 bonded channels: Reported ranges using home cabling & splitters:Power : -13.2 to -10.4 dBmV <-- BAD! SNR : 37.5 to 39.6 dBReported ranges after direct cable connection:Power : + 7.9 to +10.2 dBmV SNR : 40.4 to 41.5 dB So then I began testing all the various splitters I had on hand, by directly adding each, one-by-one, between the cable line from the street and my CM1000 modem: Rating Brand Comments1/5 IDEAL 4 way splitter Junk. Noticeable quality drop off above 700000000 Hz2/5 Comscope (red) splitter Poor, recommended and provided by last Comcast tech3/5 TVC 3.5db / 7db splitter Good, but not great; original equip, installed new in 19984/5 Using GE (square) splitter Quite good, surprising since I see posts bashing these5/5 Extreme (square) splitter Very good, numbers were nearly the same as direct connect So in the end, I discovered that my poor signal quality issues were primarily due to the splitters I was using (and by mistakenly trusting a Comcast tech to provide a good quality splitter which was crap). Even worse, I had been using two splitters in series--one at the main manifold in the attic, then another in the family room splitting a line between the cable TV box and the CM1000 modem--which further degrading the signal. My "semi-scientific" testing also showed that just the original house cabling itself was dropping the signal a noticeable amount as well. I'm not sure if it was the run-length causing it or the quality of the cable used from 1998. Regardless, I now have the info I need to change out the inside components to effect a much better signal. So the CM1000 modem and its recent firmware were not a contributing factor in my particular case.

I'm having the exact same issue. My new CM1000 modem is logging dozens of the following message triplets per day and a simple ping shows that I'm dropping lots of packets because of it, which obviously is messing up my throughput and general internet usability (MAC value intentionally masked): RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;RNG-RSP CCAP Commanded Power Exceeds Value for Pmax;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;Dynamic Range Window violation I also have Comcast/Xfinity (West Palm Beach, FL area) and have been frustrated with this. The closest info I've been able to find is some other forum where someone posted a similar problem and stated that that after some advanced troubleshooting, they eventually determined it was an issue with the software running on the box on the pole, and had nothing to do with his wiring to or within the home.So I'm not sure if that issue is related, or if there is a mismatch between the software installed on the external hardware vs the software being pushed to these new consumer modems, but I can tell you its frustrating. I pay for 150MB and I just ran a speed test and it returned a fraction of 1MB download speed. So once again I am rebooting everything to see if that will temporarily "heal" the issue -- until another hour or two where it happens again.

2 weeks later and no change. Still getting the errors.

I would contact the ISP could be a issue with the power levels or the lines causing these errors. DarrenM

CM1000 RNG-RSP Issues | NETGEAR Communities

15 Replies

OrbiWANKenobi
Star
Oct 21, 2017
I'm having the exact same issue. My new CM1000 modem is logging dozens of the following message triplets per day and a simple ping shows that I'm dropping lots of packets because of it, which obviously is messing up my throughput and general internet usability (MAC value intentionally masked):

RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
RNG-RSP CCAP Commanded Power Exceeds Value for Pmax;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Dynamic Range Window violation

I also have Comcast/Xfinity (West Palm Beach, FL area) and have been frustrated with this. The closest info I've been able to find is some other forum where someone posted a similar problem and stated that that after some advanced troubleshooting, they eventually determined it was an issue with the software running on the box on the pole, and had nothing to do with his wiring to or within the home.
So I'm not sure if that issue is related, or if there is a mismatch between the software installed on the external hardware vs the software being pushed to these new consumer modems, but I can tell you its frustrating. I pay for 150MB and I just ran a speed test and it returned a fraction of 1MB download speed. So once again I am rebooting everything to see if that will temporarily "heal" the issue -- until another hour or two where it happens again.
- DarrenM
  Sr. NETGEAR Moderator
  Oct 24, 2017
  I would contact the ISP could be a issue with the power levels or the lines causing these errors.
  
  DarrenM
  - Frizzel
    Initiate
    Oct 25, 2017
    I did contact Comcast and they said the levels in my area look fine. Had a tech come out and he checked the line going into the house and his words were "it couldnt be any more perfect than this, if it started after the new firmware, thats all I can think of" which, he is right, it started after the new firmware was pushed. So either this firmware is telling me theres something wrong with the modem and its not happy with the levels for whatever reason, or theres another issue, its related to this firmware. I am still talking with comcast to see if they have any other ideas on what to try. As it stands the modem either reboots on its own or I have to do it by hand to get a connection again.
- OrbiWANKenobi
  Star
  Dec 06, 2017
  Just an update from my earlier post: Same issue, same firmware version with no update. I'm only typing this now because I've been having to reset my modem several times a day (at least) to have any decent throughput (I pay for 150MB) until it craps out again and takes my internet speed down to a drip-drip rate.
  
  I would really like to see someone in an official capacity comment on this from Netgear, instead of this "community" just standing around scratching our heads and talking into a void. There is someone somewhere over in Netgear engineering who knows exactly what types of things might trigger this issue. That information, in turn, could then be used to inform Comcast techs on how to fix it. Or Netgear themselves could issues a patch that would bring back some reasonable stability to these units until further research can be done to correct it. Perhaps they could add a software option to enable/disable something that would make the modem operate more like my older Netgear modems did.
  - n4cho
    Apprentice
    Dec 09, 2017
    I need to say that my modem has started acting up also. Its not giving out an address to my router, my speed it cut in half, when it is working the speed is so slow I cant pull email. I have had to reboot my router 5 times and reset it once since I have been home just to get an IP address to type this. My speed is significantly reducted (300/30 at 100/5). I just started having issues today and my firmware is the same as what is listed here.
    
    Feeds an Orbi for what its worth.....
    
    -Jack
- AidMeNow
  Aspirant
  Mar 20, 2018
  I have the same issue. ISP= Mediacom
  It seems that the DocSys 3.1 technology cannot be properly implemented by the ISP advertising that 1GB down stream service. The line runs too hot the Node pops an error then you and a few neighbors lose signal for a few minutes to an hour and the cycle begins again.
  It seems to have something to do witht he SYNC time Syncronization error. Aka the Timing that the ISP uses kind of like your PC clock.
  3-17-2018, 9:37:27 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:10:10:11:51:41;CM-QOS=1.1;CM-VER=3.1;"
  Event Log Issues week of 3202018.pdf338 KB
vitocorleone
Tutor
Nov 11, 2017
My CM1000 also suffers the same thing, except the auto-reboots, ever since the firmware update - it's been fine with few error messages for months until this firmware. I'm on Comcast in Seattle. I'd have to say that this is one of the most fussy, problematic modems I've ever owned.
- vitocorleone
  Tutor
  Nov 22, 2017
  2 weeks later and no change. Still getting the errors.

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CM1000 RNG-RSP Issues