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Visitor

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3 Messages

Thu, Jul 7, 2022 8:24 PM

CM2000 high ping spikes and speeds dropping under 1Mbps sporadically

I upgraded my CM1200 modem to a CM2000 because the website said the prior modem was not compatible with our Xfinity gig service.  The CM2000 was listed on the approved 3rd party device list, however that site no longer will load and I was told by your technician that came on site this past Tuesday that our modem doesn't support gigabit service. That modem is rated for up to 2.5gb connections and is DOCSIS 3.1 so I don't think that's the issue. He showed me on his phone app where my account had a red notice saying tell the customer their device isn't capable of the provided speeds. 

On top of that, we are seeing random ping spikes and speeds tanking to near dial-up speeds from the 90s that will last up to several minutes and go back to normal or require a device reboot to fix. This happens even when plugged directly into the modem, with no routers or other devices between the PC and the modem. All the ethernet cables are Cat6, brand new, and have been swapped with spares with nothing fixing the issue. I'm pasting the modem log below from the last week and praying someone can assist with this since it's been going on for months now.

Thu Jul 07 13:50:53 2022 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Thu Jul 07 13:50:48 2022 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Time Not Established (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Wed Jul 06 17:31:15 2022 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Wed Jul 06 17:31:10 2022 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Time Not Established (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Wed Jul 06 17:30:10 2022 (Critical (3)) Resetting the cable modem due to docsDevResetNow
Wed Jul 06 13:03:57 2022 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Mon Jul 04 16:48:13 2022 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Mon Jul 04 16:48:13 2022 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Mon Jul 04 16:48:08 2022 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Time Not Established (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Mon Jul 04 16:47:05 2022 (Critical (3)) Resetting the cable modem due to docsDevResetNow
Mon Jul 04 08:34:57 2022 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=6redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 02 07:42:21 2022 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 02 07:42:16 2022 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Time Not Established (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 02 07:03:51 2022 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=redacted;CMTS-MAC=redacted0;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 02 07:03:46 2022 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Time Not Established (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 02 07:02:44 2022 (Critical (3)) Resetting the cable modem due to docsDevResetNow
Fri Jul 01 11:37:45 2022 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Fri Jul 01 11:37:40 2022 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Time Not Established (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Fri Jul 01 11:36:40 2022 (Critical (3)) Resetting the cable modem due to docsDevResetNow
Thu Jun 30 09:48:18 2022 (Warning (5)) Dynamic Range Window violation
Thu Jun 30 09:48:18 2022 (Warning (5)) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Wed Jun 29 23:06:19 2022 (Warning (5)) Dynamic Range Window violation
Wed Jun 29 23:06:19 2022 (Warning (5)) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Wed Jun 29 21:34:55 2022 (Warning (5)) Dynamic Range Window violation
Wed Jun 29 21:34:55 2022 (Warning (5)) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Wed Jun 29 19:21:12 2022 (Warning (5)) Dynamic Range Window violation
Wed Jun 29 19:21:12 2022 (Warning (5)) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
Wed Jun 29 17:17:59 2022 (Warning (5)) Dynamic Range Window violation

Accepted Solution

Visitor

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3 Messages

4 months ago

Just as an update, since I've been working with xfinity reps via direct message since my initial post, a technician came out and verified the wiring to the home and our equipment were all in good shape and not the cause. Our cable connection was run from a pole across the street and was right next to the amp, which the technician said was likely causing the sporadic nature of the connection issues we were seeing. They scheduled a bucket truck with the maintenance people, who did some sort of work on the line at the pole, and we were given a coax splitter to attach at the modem end of our connection. Since the line work and the addition of the splitter we have had no interruptions in service, and all the errors on the modem logs have stopped. We're optimistic our issue is finally resolved, but going to monitor the modem over the next couple weeks.

Visitor

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3 Messages

5 months ago

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 423000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 4 423000000 Hz 4.7 dBmV 43.9 dB 0 0
2 Locked QAM256 1 405000000 Hz 4.7 dBmV 44.0 dB 0 0
3 Locked QAM256 2 411000000 Hz 4.7 dBmV 43.9 dB 0 0
4 Locked QAM256 3 417000000 Hz 4.8 dBmV 44.0 dB 0 0
5 Locked QAM256 5 429000000 Hz 4.9 dBmV 44.0 dB 0 0
6 Locked QAM256 6 435000000 Hz 4.9 dBmV 43.9 dB 0 0
7 Locked QAM256 7 441000000 Hz 4.8 dBmV 43.9 dB 0 0
8 Locked QAM256 8 453000000 Hz 4.9 dBmV 44.0 dB 0 0
9 Locked QAM256 9 459000000 Hz 5.1 dBmV 44.1 dB 0 0
10 Locked QAM256 10 465000000 Hz 5.2 dBmV 44.1 dB 0 0
11 Locked QAM256 11 471000000 Hz 5.3 dBmV 44.1 dB 0 0
12 Locked QAM256 12 477000000 Hz 5.4 dBmV 44.1 dB 0 0
13 Locked QAM256 13 483000000 Hz 5.5 dBmV 44.2 dB 0 0
14 Locked QAM256 14 489000000 Hz 5.5 dBmV 44.2 dB 0 0
15 Locked QAM256 15 495000000 Hz 5.6 dBmV 44.3 dB 0 0
16 Locked QAM256 16 501000000 Hz 5.6 dBmV 44.3 dB 0 0
17 Locked QAM256 17 507000000 Hz 5.7 dBmV 44.4 dB 0 0
18 Locked QAM256 18 513000000 Hz 5.6 dBmV 44.4 dB 0 0
19 Locked QAM256 19 519000000 Hz 5.7 dBmV 44.4 dB 0 0
20 Locked QAM256 20 525000000 Hz 5.6 dBmV 44.4 dB 0 0
21 Locked QAM256 21 531000000 Hz 5.7 dBmV 44.4 dB 0 0
22 Locked QAM256 22 537000000 Hz 5.6 dBmV 44.3 dB 0 0
23 Locked QAM256 23 543000000 Hz 5.7 dBmV 44.4 dB 0 0
24 Locked QAM256 24 549000000 Hz 5.7 dBmV 44.4 dB 0 0
25 Locked QAM256 25 555000000 Hz 5.9 dBmV 44.4 dB 0 0
26 Locked QAM256 26 561000000 Hz 6.1 dBmV 44.4 dB 0 0
27 Locked QAM256 27 567000000 Hz 6.2 dBmV 44.5 dB 0 0
28 Locked QAM256 28 573000000 Hz 6.2 dBmV 44.5 dB 0 0
29 Locked QAM256 29 579000000 Hz 6.3 dBmV 44.5 dB 0 0
30 Locked QAM256 30 585000000 Hz 6.3 dBmV 44.4 dB 0 0
31 Locked QAM256 31 591000000 Hz 6.4 dBmV 44.4 dB 0 0
32 Locked QAM256 32 597000000 Hz 6.5 dBmV 44.4 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 35600000 Hz 45.0 dBmV
2 Locked ATDMA 2 5120 29200000 Hz 44.5 dBmV
3 Locked ATDMA 3 5120 22800000 Hz 44.0 dBmV
4 Locked ATDMA 4 5120 16400000 Hz 43.5 dBmV
5 Locked ATDMA 5 1280 39600000 Hz 42.0 dBmV
6 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
 
Downstream OFDM Channels
Channel Lock
Status Modulation /
Profile ID Channel
ID Frequency Power SNR /
MER Active Subcarrier
Number Range Unerrored
Codewords Correctable
Codewords Uncorrectable
Codewords
1 Locked 0 ,1 193 690000000 Hz 8.1 dBmV 44.9 dB 1108 ~ 2987 11229297 1052878 0
2 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0
 
Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV

Official Employee

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181 Messages

Hello @user113311 I do apologize for the issues you've encountered with your modem, we viewed the error log, and my team would like to assist.

 

To send a direct message [private message]:

   Click "Sign In" if necessary
   Click the "Direct Message" icon or https://comca.st/3uzd70e
   Click the "New message" (pencil and paper) icon
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   - As you are typing a drop-down list appears. Select "Xfinity Support" from that list.
   - An "Xfinity Support" graphic replaces the "To:" line.
   Type your message in the text area near the bottom of the window
   Press Enter to send it

 

 

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We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

Contributor

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93 Messages

5 months ago

I got a few emails from Comcast saying I needed to upgrade my device after installing a CM2050V (same as yours except it supports phone service) then upgrading to 1200/35 after installing and activating the CM2050V.  In other words their system has some issues processing device updates in a timely manner... or perhaps the old device stays on your account for a while and you get flagged if you have an incompatible device even if you have two devices.  The devices page on Comcast's web site showed my old modem and my new one for a while after I upgraded.  The tech ought to know better.

Your signal stats look to be in spec but I'm suspicious of those error log messages.  Hopefully EG will be along sometime soon to have a look at them.

It's also entirely possible there's nothing wrong with your line or modem and Comcast is having an issue with some equipment on their end.  I've had that happen a couple of times.

EG

Expert

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96.9K Messages

5 months ago

O/k so even though the signal stats looked very good at that snapshot in time, the error log entries confirm that something is going on. Perhaps there is noise ingress into the line(s) / an upstream channel / return path impairment somewhere.


There are other signal stat values that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.


I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They will be able to poll the CMTS (Cable Modem Termination System) to check for any real-time degradation and / or error reports, see your node / cable plant, and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !

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