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Wednesday, August 9th, 2023 10:16 PM

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Modem & Router interruptions: Dynamic Range Window Violation and Modem LED confusion

Hi,

I have a Netgear CM2050V cable modem and an Asus XD6 router (for a mesh network). Recently, there have been interruptions between the modem and router where the router LED indicates no internet connection though the modem LEDs are stable. Powering on/off the router always resolves the issues. More recently I'm getting a "modem offline" in the Xfinity app and the modem LED for both power and downstream are not lit at all even though the modem is operating fine and the router shows no interruption.  The cables between the modem and router are Cat5e. In looking at the modem even log I saw the following Warning message

Dynamic Range Window Violation

RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW (there are mac addresses after this that I didn't include)

I don't know what any of this means and if it is related to the periodic outage. Also, the modem status page when logged into the Netgear CM2050v says everything is fine. I have no idea why the LED lights for both power and downstream are not lit up.

Appreciate any thoughts.

Problem Solver

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1.5K Messages

2 years ago

The power LED should always work, so odd.  Maybe that one isn't long for this lifetime, or some "magic smoke" leaked out of the silicon. Your error log is telling you that you really ought to be looking at your signal table though on the modem.  Click on that status Icon to get to the table.  There's a guide here on what you should be seeing on power levels:    https://forums.xfinity.com/conversations/your-home-network/internet-troubleshooting-tips/602dae4ac5375f08cde52ea0  

A lot of uncorrectable errors?  Maybe it can run OK "wounded" for quite a long time too if you don't mind if it flakes out sometimes.  Lights not working on a netgear is not something I'd call normal.  Might want to keep your eyes open for a sale while you do some connection debugging.

(edited)

3 Messages

@flatlander3​ Thanks. I don't really understand the logs but I think I have some upstream power levels that periodically exceed the band (based on the link you included). Looks like the following:

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 16400000 Hz 44.5 dBmV
2 Locked ATDMA 2 5120 22800000 Hz 45.3 dBmV
3 Locked ATDMA 3 5120 29200000 Hz 45.3 dBmV
4 Locked ATDMA 4 5120 35600000 Hz 51.5 dBmV

Downstream Bonded Channels

Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 32 579000000 Hz 3.6 dBmV 41.8 dB 1639 765
2 Locked QAM256 4 405000000 Hz 5.8 dBmV 42.9 dB 2882 9501
3 Locked QAM256 5 411000000 Hz 5.5 dBmV 42.7 dB 2990 9185
4 Locked QAM256 6 417000000 Hz 5.5 dBmV 42.7 dB 2974 9975

Thanks for the reply!

Visitor

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15 Messages

2 years ago

Hmmm..... I have seen this type of problem on Netgear routers before, and the problem was due to a dying power adapter. The adapter would intermittently output a reduced voltage, such that the device still had SOME level of functionality but was clearly having issues. The LEDs would start blinking rapidly and the device would usually become completely unresponsive some time later. 

Power LEDs being funky are usually problems with just that, the power, either from a problem with the adapter or the actual incoming electrical service. I have seen modems have strange issues in regards to their other LEDs; an old Zoom modem I had would intermittently start flashing its Downstream LED, though the device would still be operating just fine, and Zoom eventually confirmed this as a firmware issue. Power LEDs should generally work or not, though. Good luck!

3 Messages

@user_6ff608​ Yes, this is very weird in that I've not seen a power led be off but everything working. I didn't think about it being an issue with an adapter though I had a power supply unit issue once with an xbox.  the modem is only 6 months old but I guess it could be this. According to the modem status page the firmware is up to date. I'm considering resetting to factory and seeing what happens. It's also clearly sending weird info to Xfinity, in that the Xfinity app will say my modem isn't connected when it is and everything is working fine. The later it says everything is working when nothing has happened on my end (as far as I know). Beginning to wonder if that app report is coincidental with the warning error message in my modem event log.

thanks for the reply!

Problem Solver

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1.5K Messages

@user_78fca8​  6 months, check with Netgear.  They might RMA that one or discount another one for you.

I do like the trying another power supply theory idea though before going through the signal debugging part just to see.  It might be a waste of time if the thing is wounded.

Check the voltage and amp output to make sure you can supply enough amperage with the test supply.

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