U

Visitor

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13 Messages

Thu, Jun 23, 2022 7:16 PM

Motorola MB8611 dropping connection randomly

I have a Motorola MB8611 connected to a Netgear XR1000 router for my internet and I've been noticing that it is dropping internet connection sometimes for seemingly no reason. I just recently read a thread about someone with the same issue and I was just wondering if someone with knowledge of this could give me a hand in figuring some things out. I use the internet a lot on my days off and its just frustrating for it to go down out of nowhere. 

EG

Expert

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94.4K Messages

11日前

First. Is this with a WiFi connection ? If so, for a test, does a computer / device that is hardwired directly to the Netgear router with an ethernet cable have the same problem ?


With this test, we are trying to isolate this down to being either a WiFi-only problem or a problem with the general connection to the Comcast system which would of course affect both. It's a good first step of troubleshooting before proceeding any further. 

Visitor

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13 Messages

11日前

It is on a pc that is hardwired to the router.

Visitor

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13 Messages

11日前

Wifi never goes out, just loss of internet connection. 

EG

Expert

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94.4K Messages

11日前

O/k what do the modem's signal stats 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.

Visitor

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13 Messages

11日前

 
Connection
   Startup Sequence    
   Startup Step Status Comment

  
   Acquire Downstream Channel 549000000 Hz Locked
  
   Upstream Connection OK Operational
  
   Boot State OK Operational

  
   Configuration File OK
  
   Security Enabled BPI+
  


   Connection Status    
   System Up Time 0 days 02h:55m:44s  
  
   Network Access Allowed  
  


   Downstream Bonded Channels  
  
   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1 Locked QAM256 20 549.0 1.6 41.1 0 0
   2 Locked QAM256 13 507.0 2.0 41.4 0 0
   3 Locked QAM256 14 513.0 1.9 41.5 0 0
   4 Locked QAM256 15 519.0 1.8 41.4 0 0
   5 Locked QAM256 16 525.0 1.8 41.3 0 0
   6 Locked QAM256 17 531.0 1.8 41.3 0 0
   7 Locked QAM256 18 537.0 1.8 41.3 0 0
   8 Locked QAM256 19 543.0 1.7 41.2 0 0
   9 Locked QAM256 21 555.0 1.6 41.3 0 0
   10 Locked QAM256 22 561.0 1.7 41.2 0 0
   11 Locked QAM256 23 567.0 1.7 41.3 0 0
   12 Locked QAM256 24 573.0 1.7 41.3 0 0
   13 Locked QAM256 25 579.0 1.6 41.2 0 0
   14 Locked QAM256 26 585.0 1.6 41.1 0 0
   15 Locked QAM256 27 591.0 1.6 41.3 0 0
   16 Locked QAM256 28 597.0 1.5 41.2 0 0
   17 Locked QAM256 29 603.0 1.4 41.1 0 0
   18 Locked QAM256 30 609.0 1.2 41.2 0 0
   19 Locked QAM256 31 615.0 1.0 41.0 14 0
   20 Locked QAM256 32 621.0 1.0 41.0 28 0
   21 Locked QAM256 33 627.0 0.8 41.0 33 0
   22 Locked QAM256 34 633.0 0.8 40.9 44 0
   23 Locked QAM256 35 639.0 0.7 41.0 37 1
   24 Locked QAM256 36 645.0 0.7 40.9 41 2
   25 Locked QAM256 37 651.0 0.8 41.0 49 1
   26 Locked QAM256 38 657.0 0.9 41.1 37 2
   27 Locked QAM256 39 663.0 1.0 41.1 25 13
   28 Locked QAM256 40 669.0 1.0 41.2 25 0
   29 Locked QAM256 41 675.0 1.0 38.7 9 0
   30 Locked QAM256 42 681.0 1.1 41.4 0 0
   31 Locked QAM256 43 687.0 1.3 41.3 0 0
   32 Locked QAM256 44 693.0 1.2 41.2 0 0
   33 Locked OFDM PLC 193 702.0 1.4 40.3 537844 0


   Upstream Bonded Channels  
  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Locked SC-QAM 1 5120 35.6 40.5
   2 Locked SC-QAM 2 5120 29.2 40.8
   3 Locked SC-QAM 3 5120 22.8 40.8
   4 Locked SC-QAM 4 5120 16.4 40.8
   5 Locked SC-QAM 5 2560 40.4 40.3
   6 Locked SC-QAM 6 2560 10.4 41.3


   Downstream Frequency Setting    
   Downstream Frequency Select   
  

Visitor

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13 Messages

11日前

Is this what you are looking for?

EG

Expert

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94.4K Messages

11日前

Yes. The stats are good / within spec. Are there any modem RF error log entries being shown ? If so, please post them as well in their entirety (copy and paste them, don't post a screenshot) but redact the CM MAC and the CMTS MAC addresses for your privacy. They are considered to be personal information. The posting of personally identifying information is a violation of their forum guidelines. The forum bot will not allow your post to be seen publically.

Visitor

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13 Messages

11日前

  Time Not Established   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    Time Not Established   Notice (6)   Honoring MDD; IP provisioning mode = IPv6
    14:03:10
Thu Jun 23 2022
  Notice (6)   DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;
    16:43:52
Thu Jun 23 2022
  Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;
 

These are the most recent error log entries

EG

Expert

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94.4K Messages

11日前

Any more ? If so, I need to see the balance please.

Visitor

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13 Messages

11日前

    18:12:02
Thu Jun 23 2022
  Warning (5)   RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;
    18:12:02
Thu Jun 23 2022
  Warning (5)   Dynamic Range Window violation
    19:18:27
Thu Jun 23 2022
  Warning (5)   RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;
    19:18:27
Thu Jun 23 2022
  Warning (5)   Dynamic Range Window violation

These just got logged while I was playing a game on my PC. I will also post previous logs as well 

Visitor

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13 Messages

11日前

  00:18:34
Wed May 11 2022
  Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
    00:21:53
Wed May 11 2022
  Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    00:25:42
Wed May 11 2022
  Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    00:29:32
Wed May 11 2022
  Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    00:30:17
Wed May 11 2022
  Critical (3)   TFTP failed - Request sent - No Response;
    00:30:17
Wed May 11 2022
  Critical (3)   TFTP Request Retries exceeded, CM unable to register
    00:31:05
Wed May 11 2022
  Critical (3)   TFTP failed - Request sent - No Response;
    00:31:05
Wed May 11 2022
  Critical (3)   TFTP Request Retries exceeded, CM unable to register
    00:31:54
Wed May 11 2022
  Critical (3)   TFTP failed - Request sent - No Response;
    00:31:54
Wed May 11 2022
  Critical (3)   TFTP Request Retries exceeded, CM unable to register
    00:32:41
Wed May 11 2022
  Critical (3)   TFTP failed - Request sent - No Response;
    00:32:42
Wed May 11 2022
  Critical (3)   TFTP Request Retries exceeded, CM unable to register
    00:33:12
Wed May 11 2022
  Critical (3)   No Ranging Response received - T3 time-out;
    00:37:43
Wed May 11 2022
  Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;
    00:42:43
Wed May 11 2022
  Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
    00:45:31
Wed May 11 2022
  Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    00:46:15
Wed May 11 2022
  Critical (3)   No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;
    00:46:26
Wed May 11 2022
  Critical (3)   SYNC Timing Synchronization failure - Loss of Sync;
    00:46:49
Wed May 11 2022
  Critical (3)   No Ranging Response received - T3 time-out;
    Time Not Established   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    18:14:27
Wed May 18 2022
  Critical (3)   SYNC Timing Synchronization failure - Loss of Sync;
    Time Not Established   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    11:45:15
Fri Jun 3 2022
  Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;
    10:30:07
Mon Jun 6 2022
  Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;

Here are all the other logs in the event log section

Official Employee

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820 Messages

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EG

Expert

 • 

94.4K Messages

10日前

O/k so even though the signal stats looked o/k 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 !

Visitor

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13 Messages

@EG​ Thank you so much I really appreciate the help! 

EG

Expert

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94.4K Messages

@user_4206996​ 

My pleasure ! Please post back here with how things turn out.

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

Visitor

 • 

13 Messages

@EG​ I've been doing some more research and it seems like this is a common problem with mb8611 modems. Have you noticed the same thing being an expert on these forums?

EG

Expert

 • 

94.4K Messages

@user_4206996​ 

Yes. I've seen evidence of a common thread among them !

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

Visitor

 • 

13 Messages

@EG​ [Edited: "Language"], if it turns out to just be the modem, what would you recommend as a replacement? Xfi gateway in bridge mode or new third party modem? 

(edited)

EG

Expert

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94.4K Messages

10日前

Personally, I would go with the latter.

Visitor

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13 Messages

@EG​ Any stand outs that you would recommend so if it is the modem I can get a new one asap 

EG

Expert

 • 

94.4K Messages

9日前

I prefer not to recommend particular brands / models of modems, sorry. Just go with one that is compatible with your subscribed to speed tier here: https://www.xfinity.com/support/devices 

Visitor

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13 Messages

6日前

Xfinity came by over the weekend and said everything was in the green and looked good. Tech removed a couple filters for multi room dvr that I didn’t need anymore and checked all connections. Now I am not getting the download speeds I was seeing before. So I thought it was the modem but after hooking up my xfi unit I had even worse speed and connection issues. 

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