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Good morning folks. I have been having an issue with my Cox service for quite sometime. The internet will just "vanish", but the Eth0 & WiFi will continue to work fine. At first, thought it was our router, so purchased a TP-Link AX6000. Still doing the same thing. So, upgraded the router. Cox had mentioned that we would need to upgrade to a DOCSIS v3.1 anyways, so why not. Purchased the CM1000v2 and still having the same results. All the lights stay on and functioning, which is why I originally thought it was the router. Only way to fix it is to power cycle the modem and works fine for a couple days, then same issues all over again.
I had Cox Contractor out last month, and he replaced the line from the Ped (only about 10 yards from our house) to the house. Changed the RG-6 fittings on the line that goes in to the house for approx. 5 feet to the modem, straight from the box outside that wall.
I had to reboot the modem about an hour ago because the internet vanished again. Here are the details of what the modem connection currently looks like while running.
We are on the Cox Gigablast Plan just FYI. Below is the Firmware Info, Connection & Event Logs.
Cable Modem Serial Number
CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2.;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
Dynamic Range Window violation
RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
TLV-11 - unrecognized OID;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
DHCP WARNING - Non-critical field invalid in response ;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
Time Not Established
Honoring MDD; IP provisioning mode = IPv4
UCD invalid or channel unusable;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
No Ranging Response received - T3 time-out;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
Resetting the cable modem due to docsDevResetNow
Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=94:a6:7e:0c:xx:xx;CMTS-MAC=00:c1:b1:60:f7:94;CM-QOS=1.1;CM-VER=3.1;
Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Acquire Downstream Channel
IP Provisioning Mode
<tabindex=-1>Downstream Bonded Channels</tabindex=-1>
SNR / MER
<tabindex=-1>Upstream Bonded Channels</tabindex=-1>
<tabindex=-1>Downstream OFDM Channels</tabindex=-1>
Modulation / Profile ID
Active Subcarrier Number Range
0, 1, 2, 3
1108 ~ 2987
0 ~ 4095
<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>
Current System Time: Sat Apr 23 08:41:12 2022
System Up Time: 1:06:13
The SNR is low for the OFDM channel which is the 300Mhz range. I also see error in the logs about the OFDM channel. Finally I see a T4 error, which is a full reset. I would try to bypass all splitters for a day and see if a direct connection from the street to the room the modem is in helps. If not, schedule a technician.
Sorry, I thought I put it in the 2nd paragraph that there are no splitters or anything at all. The line goes from the Underground Ped about 5 yards outside the house, to the J-Box, which was replaced last month where there was a Cox Contractor out here. From there, only thing is a barrel connection to the 6' line that goes from the J-Box, in to the house where the modem is at.
So all in all total, the single line which has no splitters, amps, or anything else is approx. 6 1/2 yards total in length (approx. 100').
This modem worked perfectly fine at my old house which was also on Cox in a different city, different head end, etc., but here, it constantly continues to lock up the internet service and have to manually power cycle. The app itself that Cox has can't even communicate with the modem to reset it when it is hung.
Sorry I missed the part about a direct connection in OP. I think the problem is the OFDM channel and noise on that frequency. Getting the right tech. out there that has a DOCSIS 3.1 meter is tough. It also needs to be properly escalated to maintenance usually and I don't think a contractor can do that. So I would try to get a in-house tech. out there. Good luck.
No problem.. :-)
I made sure to specifically ask for an In-House tech. Now whether the CS Rep put a note in there so dispatch won't send it to the Contractor queues, and keep it in-house, who knows.
So my question is this.. They throw an attenuator on the line, and it brings numbers to normal (-7 / +7), do they just stop there and call it a day? I mean if there's THAT much power output on the Tap, it's got to be causing issues elsewhere as well. Guess just replacing the tap in the Ped won't fix anything, since it seems almost like it's further down the line causing all the problems, unless there's an Amp right in this pedal outside.
Am I wrong?
A attenuator may help but it won't fix the low SNR on the OFDM channel. Replacing or at least repairing the ped. would be a better first step IMO. I think it all depends what the tech. finds with his meter. There is no saying where the noise is leaking in. The only thing that has been isolated is it's not inside your house.
PS. You may want to edit out your modem's MAC address from OP. That is personal.
WiderMouthOpen, done with the edit. TY. I removed it in one spot, but not the others originally...
So on the OFDM channel, that 32.8db is low? Should it be up like the others at 42+?
Also, the other OFDM channel shows not locked or anything, but does show a signal being there. Is that normal to have some of those channels not locked or working at all when provisioned for GigaBlast service?
CWaters75 said:So on the OFDM channel, that 32.8db is low? Should it be up like the others at 42+?
From what I have observed in other people signal levels, yes. Technically 256 QAM has a minimal SNR of 30, but I don't know what QAM(modulation?) the OFDM channel is. Lower modulation has lower SNR. What makes me think it has something to do with the SNR are the errors:
"CM-STATUS message sent. Event Type Code: 16; Chan ID: 159"
See post here that goes over what event type 16 means. Please note this is all rudimental troubleshooting based on the limited data the modem gives. A meter will be able to tell a lot more.
WiderMouthOpen - So waiting for the Cox Tech to get here this morning, and just logged in to the modem to see what the values are at this morning, as this is the 3rd day with internet, and usually the 4th is when I have to reboot because I have no access.
That OFDM channel is now at 11.7dBmV and 43.0dB with 4 Uncorrectable Codewords.
All the QAM256 locked channels are now anywhere from 14.3 dBmV - 15.6 dBmV and 44.6-50 dB on the SNR/MER channels.
CWaters75 said:That OFDM channel is now at 11.7dBmV and 43.0dB with 4 Uncorrectable Codewords.
Do you know anything that changed? Or did it change on it's own? Either way, as long as it stays that way, it is good. I assume your not getting type 16 errors in your log anymore right?
No, I did not change anything at all, and they haven't been here yet to T-Shoot and/or throw an attenuator in line or see what the hell is going on.
And I have THREE PAGES of Type 16 Error notices this morning. That's all that is in my event log over the last 24 hours are Type 16's.