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user_zg50ac
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Wednesday, March 11th, 2026 4:03 PM

Internet keeps dropping with DS Profile Assignment Change in Cable Modem Log

I am currently using a Motorola MB8611 cable modem which has been in service for the past couple of years without issue. My internet keeps dropping for a couple of minutes intermittently with the event log entry of DS Profile Assignment Change and then reconnects without me having to reboot the modem. Xfinity has sent a technician out to check the outside lines and reported no issues but is trying to put the blame on my internal network hardware ( TP-Link Deco BE63 BE10000). Only thing is when the disconnection occurs, all devices remain connected to the wireless/wired LAN and I am still able to communicate with my modem. JUST NO CONNECTION TO THE INTERNET from my ISP....Any suggestions on what next steps I could take?

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EG

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1 day ago

What do the modem's signal status values look like ? Try getting them here;

http://192.168.100.1 


Please copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.

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user_zg50ac

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@EG​ 

Downstream Bonded Channels  
  
   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1 Locked QAM256 20 519.0 7.8 45.4 0 0
   2 Locked QAM256 1 405.0 7.5 45.7 0 0
   3 Locked QAM256 2 411.0 7.5 44.9 0 0
   4 Locked QAM256 3 417.0 7.4 45.5 0 0
   5 Locked QAM256 4 423.0 7.4 45.6 0 0
   6 Locked QAM256 5 429.0 7.4 45.5 0 0
   7 Locked QAM256 6 435.0 7.4 45.4 0 0
   8 Locked QAM256 7 441.0 7.2 45.5 0 0
   9 Locked QAM256 8 447.0 7.4 45.5 0 0
   10 Locked QAM256 9 453.0 7.5 45.5 0 0
   11 Locked QAM256 10 459.0 7.5 45.5 0 0
   12 Locked QAM256 11 465.0 7.5 45.5 0 0
   13 Locked QAM256 12 471.0 7.6 45.5 0 0
   14 Locked QAM256 13 477.0 7.7 45.5 0 0
   15 Locked QAM256 14 483.0 7.6 45.3 0 0
   16 Locked QAM256 15 489.0 7.8 45.3 0 0
   17 Locked QAM256 16 495.0 7.8 45.5 0 0
   18 Locked QAM256 17 501.0 7.8 45.4 0 0
   19 Locked QAM256 18 507.0 7.8 45.3 0 0
   20 Locked QAM256 19 513.0 7.8 45.3 0 0
   21 Locked QAM256 21 525.0 7.8 45.2 0 0
   22 Locked QAM256 22 531.0 7.7 45.2 0 0
   23 Locked QAM256 23 537.0 7.7 45.0 0 0
   24 Locked QAM256 24 543.0 7.6 44.9 0 0
   25 Locked QAM256 25 555.0 7.5 45.0 0 0
   26 Locked QAM256 26 561.0 7.5 44.9 0 0
   27 Locked QAM256 27 567.0 7.6 44.9 0 0
   28 Locked QAM256 28 573.0 7.6 44.9 0 0
   29 Locked QAM256 29 579.0 7.7 45.0 0 0
   30 Locked QAM256 30 585.0 7.7 44.6 0 0
   31 Locked QAM256 31 591.0 7.9 44.9 0 0
   32 Locked QAM256 32 597.0 7.9 44.9 0 0
   33 Locked OFDM PLC 193 805.0 9.1 44.5 24337456 0


   Upstream Bonded Channels  
  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Locked SC-QAM 17 5120 16.4 42.5
   2 Locked SC-QAM 18 5120 22.8 42.5
   3 Locked SC-QAM 19 5120 29.2 42.8
   4 Locked SC-QAM 20 5120 35.6 43.0
   5 Locked SC-QAM 21 2560 40.4 42.0
   6 Locked SC-QAM 22 2560 10.4 42.0

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1 day ago

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EG

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1 day ago

The signal status values were ok at that snapshot in time. Please post the modem's RF error log entries in their entirety (copy and paste all of the text), but redact the CM and the CMTS MAC addresses for privacy or else the forum bot will not allow your post to be seen publicly.

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user_zg50ac

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7:19:12 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Tue Mar 3 2026
7:19:12 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Tue Mar 3 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
9:15:35 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Tue Mar 3 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
12:00:40 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Tue Mar 3 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
11:45:40 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Wed Mar 4 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
22:15:40 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Wed Mar 4 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
10:00:41 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Thu Mar 5 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
19:15:41 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Thu Mar 5 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
22:30:35 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Thu Mar 5 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
11:30:42 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Fri Mar 6 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
7:00:38 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Sun Mar 8 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
23:45:43 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Sun Mar 8 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
3:33:45 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Mon Mar 9 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
15:45:39 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Mon Mar 9 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
8:48:51 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Wed Mar 11 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
12:15:28 Notice (6) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Wed Mar 11 2026
12:20:11 Notice (6) CM-STATUS message sent. Event Type Code: 24; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0.;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;
Wed Mar 11 2026

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1 day ago

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user_zg50ac

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9 hours ago

@EG These new events happened since last night when my internet dropped again

Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
8:48:51 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Wed Mar 11 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
20:15:40 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Wed Mar 11 2026
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
2:15:29 Notice (6) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Thu Mar 12 2026
2:15:38 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Thu Mar 12 2026
2:21:54 Notice (6) CM-STATUS message sent. Event Type Code: 24; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Thu Mar 12 2026


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EG

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5 hours ago

@user_zg50ac 

Ok so even though the signal status values looked OK 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 (The Digital Care Team) who 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 check those upstream receive signal stats.

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

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user_zg50ac

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Thank you...I appreciate all your assistance...I am not new to the internet or even networking but getting Xfinity to accept responsibility seems to be a very difficult task....My next step is to replace my cable modem (Motorola MB8611) with a new device....I am definitely not going back to their "All in One" solution....

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4 hours ago

XfinityJon

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If you could send our team a direct message with your full name, the name listed on the account (if different), and the service address associated with your account, I'd be more than happy to look into this for you.

 

To send a Direct Message, please click on the “Direct Message” icon in the top-right corner of the screen, next to the bell icon, click the "New message" (pencil and paper) icon, then type or select "Xfinity Support". Type your message in the text area near the bottom of the window and press Enter to send your message and initiate a live session.

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
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

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4 hours ago

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EG

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@user_zg50ac​ 

Quite welcome ! Best of luck with this issue !

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

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4 hours ago

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XfinityKei

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5 hours ago

@user_zg50ac Thanks for bringing your concerns to our attention. Our team is here to help. Have you had the chance to check the connections to your modem, router and at the wall outlet to confirm everything is finger tight and secure?

Did the tech mention any suggestions for the connection during the visit?

Do you have any additional devices connected such as a separate router, Wi-Fi extenders, amplifiers or splitters connected?

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