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agp_20051023
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Friday, September 9th, 2022 1:45 PM

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Periodic very slow upload speeds and disconnects

For the last week, I have been experiencing full disconnects of service 3-4 times a day, with periods of very slow upload speeds (1Mbps or less) happening almost hourly. My recent service and modem upgrade has my speeds at 700+Mbps down and ~22Mbps up when working well.

I noticed that my MB8611 cable modem had the blue upload light flashing for short periods of time, so I checked the event logs and see this during that period (MACs obscured):

Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:13
Fri Sep 9 2022   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;08:18:15
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:16
Fri Sep 9 2022   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;08:18:16
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:17
Fri Sep 9 2022   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;08:18:20
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:21
Fri Sep 9 2022   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;08:18:22
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:23
Fri Sep 9 2022   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;08:18:26
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:27
Fri Sep 9 2022   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;08:18:29
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:30
Fri Sep 9 2022   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;08:18:30
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:31
Fri Sep 9 2022   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;08:18:34
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:35
Fri Sep 9 2022   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;08:18:36
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:37
Fri Sep 9 2022   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;08:18:37
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:38
Fri Sep 9 2022   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;08:18:40
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:41
Fri Sep 9 2022   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;08:18:42
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:43
Fri Sep 9 2022   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;08:18:44
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:45
Fri Sep 9 2022   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;08:18:46
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:18:47
Fri Sep 9 2022   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;08:18:49
Fri Sep 9 2022   Critical (3)   UCD invalid or channel unusable;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;08:19:20
Fri Sep 9 2022   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;

Connection screen looks like this:

   Downstream Bonded Channels    
  
   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1  Locked  QAM256  44  687.0  6.2  44.1  0  0
   2  Locked  QAM256  13  501.0  6.8  44.7  0  0
   3  Locked  QAM256  14  507.0  6.7  44.6  0  0
   4  Locked  QAM256  15  513.0  6.7  44.6  0  0
   5  Locked  QAM256  16  519.0  6.7  44.6  0  0
   6  Locked  QAM256  17  525.0  6.9  44.7  0  0
   7  Locked  QAM256  18  531.0  7.0  44.8  0  0
   8  Locked  QAM256  19  537.0  6.9  44.6  0  0
   9  Locked  QAM256  20  543.0  6.8  44.7  0  0
   10  Locked  QAM256  21  549.0  6.8  44.6  0  0
   11  Locked  QAM256  22  555.0  6.6  44.5  0  0
   12  Locked  QAM256  23  561.0  6.4  44.3  0  0
   13  Locked  QAM256  24  567.0  6.2  44.2  0  0
   14  Locked  QAM256  25  573.0  6.4  44.4  0  0
   15  Locked  QAM256  26  579.0  6.5  44.3  0  0
   16  Locked  QAM256  27  585.0  6.5  44.2  0  0
   17  Locked  QAM256  28  591.0  6.4  44.3  0  0
   18  Locked  QAM256  29  597.0  6.4  44.2  0  0
   19  Locked  QAM256  30  603.0  6.7  44.2  0  0
   20  Locked  QAM256  31  609.0  6.7  44.4  0  0
   21  Locked  QAM256  32  615.0  6.5  44.1  0  0
   22  Locked  QAM256  33  621.0  6.6  44.2  0  0
   23  Locked  QAM256  34  627.0  6.7  44.2  0  0
   24  Locked  QAM256  35  633.0  6.9  44.5  0  0
   25  Locked  QAM256  36  639.0  6.9  44.3  0  0
   26  Locked  QAM256  37  645.0  6.6  44.2  0  0
   27  Locked  QAM256  38  651.0  6.6  44.3  0  0
   28  Locked  QAM256  39  657.0  6.5  44.3  0  0
   29  Locked  QAM256  40  663.0  6.5  44.2  0  0
   30  Locked  QAM256  41  669.0  6.3  44.2  0  0
   31  Locked  QAM256  42  675.0  6.1  43.2  0  0
   32  Locked  QAM256  43  681.0  6.1  44.1  0  0
   33  Locked  OFDM PLC 193  957.0  4.8  43.2  3589187  0


   Upstream Bonded Channels    
  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1  Locked  SC-QAM  4  5120   35.6  28.8

THANKS!

Question

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Updated 

2 years ago

555

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CCBiancaB

Problem Solver

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574 Messages

2 years ago

Hi, @agp_20051023! Thank you for reaching out to our community forums for assistance. Please send us a direct message so we can go through troubleshooting steps to resolve the connection issues you're experiencing. Can you please click the Direct Messaging icon at the top right of the page, click on the pen and pad icon and enter Xfinity Support in the "To" section of the chat and provide us with your first and last name so we may further assist you.

(edited)

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user_611c69

Visitor

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4 Messages

2 years ago

I've been having the same issue since the previous week, during periods speedtest show 0.02Mbps on 3 different devices (wifi & ethernet).

Modem is a Zoom 5345. (FWIW i live in the Bay Area)

(edited)

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agp_20051023

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2 Messages

I have some good news to report, although I realize it may not help everyone in this situation. It is a good reminder that things can change we don't always expect or understand.

To review, everything was working great and none of my infrastructure (cabling inside and out, splitters, etc.) had changed since my original install 6+ years ago.

Working with a technician in the area, we ran a new cable from green box to modem to bypass everything local. Immediate improvement! Super fast connection negotiation, and speeds which matched the rates I am paying to have. We then added elements back to the equation to figure out possible culprits. Findings:

  • Cable from green box to house outside demarc - no issues
  • The green box had an old filter on it that was blocking more than one upload channel from connecting. With the filter on, the cable modem would try to connect to 4 channels but fail on three. With the filter off, all 4 connect immediately. BUT, still extremely slow upload speeds.
  • Xfinity had installed a Commscope powered zero return splitter in the outside demarc for the initial installation years. It still works fine for all TV signals, but was interfering with the successful upstream communication. Upon reconfiguring the connection, all download and upload speeds reached the expected rates.

So this was a great reminder that things change. Either one of the two devices were beginning to fail, OR the combination of these devices and new communication settings on the distribution side were no longer compatible.

Lesson learned - work with the experts and don't mess around with anything on your own. They have the tools and the knowledge (and permission!) to resolve these things and identify what the best current state.

2 years ago

0

EG

Expert

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104.3K Messages

2 years ago

@user_611c69 

Please create a new topic of your own here on this board detailing your issue. Thanks. 


For future reference, it is better to submit your own post as it creates a ticket to get help, and posting on an old thread can delay getting help.

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