Read the forum guidelines
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.
WiderMouthOpen - So this contractor dude was cool and he said did what the last one should have, instead of just replacing the line from the PED to the OPB and calling it a day.
He confirmed that the line levels were quite high. He said for Cox, their limits are -12/+12, and when he got here, we were at +17.9 average. So he threw a small attenuator right behind the modem to start, and I can already see a significant drop in power on the locked channels, and Upstream Bonded channels have raised signal along with the ODFM channel.
Since rebooting the modem, I now see zero correctable/uncorrectable codewords, and the OFDM has a bunch of correctable codewords, but no uncorrectable codewords. Here's the new results:
<tabindex=-1>Downstream Bonded Channels
<tabindex=-1>Upstream Bonded Channels
<tabindex=-1>Downstream OFDM Channels
<tabindex=-1>Upstream OFDMA Channels
Current System Time: Tue Apr 26 10:26:54 2022
System Up Time: 0:06:06
And as far as the Event Log:
Fingers crossed at this point...
I am now seeing a bunch of T3/T4 errors. I am hoping that was just caused by his work or testing. If not it points to noise on the upstream. Now it's just a waiting game to see if the problem repeats.
WiderMouthOpen - Just to keep an easier eye on things, right after I took the screenshots and made that last post, I cleared the Event Log. As of this post, there's ZERO entries in the Event Log, so hopefully it keeps this up and won't have any further drops.
I'll give it three or four days and try the Modem Reset feature from the app again. It worked right after the guy was done, but just like before, it works for four or five days when I started having problems and needed to reboot the modem, then it worked fine until the next time the modem froze up.
So thanks for all the help. I'll make sure to post an update here around the end of the week to see if that did the trick or not.
CWaters75 said:As of this post, there's ZERO entries in the Event Log
I will keep a eye open for a update in 3-4 days. It was nice working with you.
WiderMouthOpen - So it has been 360:57:21 that the modem has been online without having to do a power cycle on it. Seems that the "Small" Attenuator that the tech put on the line did the trick.
I see NO uncorrectable Codewords on any line for any connections now.
Thanks again for the assistance, and it was nice working with you and pointing me in the correct direction, sir!
CWaters75 said: it was nice working with you and pointing me in the correct direction, sir!
Sorry I was a little off track with the OFDM channel. Guess that was unimportant or cleared up somehow. Cheers!