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Occasional T3 timeouts

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Regular Visitor

Occasional T3 timeouts

I'm occasional T3 timeouts but my signal levels all appear to be good. Occasional being twice a day on a bad day, usually once. Ive also noticed that when I lose connection, I can view the modem stauts page until I restart. Once I power cycle, everything goes back to normal usually for the rest of the day.

 

Downstream SNR: 37-38dB

Downstream Power levels: -2 to 0 dBmV

Upstream Power levels: 39 - 40 dBmV

 

The modem is a Surfboard SB6141. When I used to have issues like this, it was a result of bad cables but was apparent from the signal levels. What should I check next?

 

Here's a copy of the log from the last episode:

Time Priority Code Message

Oct 28 2020 12:57:275-WarningZ00.0MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:263-CriticalR02.0No Ranging Response received - T3 time-out;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:176-NoticeN/ACable Modem Reboot due to T4 timeout ;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:56:073-CriticalR04.0Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:52:073-CriticalR02.0No Ranging Response received - T3 time-out;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:51:553-CriticalR06.0Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:51:553-CriticalR03.0Ranging Request Retries exhausted;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:51:543-CriticalR02.0No Ranging Response received - T3 time-out;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:51:353-CriticalR06.0Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:51:353-CriticalR03.0Ranging Request Retries exhausted;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:51:303-CriticalR02.0No Ranging Response received - T3 time-out;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:51:063-CriticalR06.0Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:51:063-CriticalR03.0Ranging Request Retries exhausted;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 12:51:063-CriticalR02.0No Ranging Response received - T3 time-out;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;
Oct 28 2020 09:32:425-WarningZ00.0MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=e8:6d:52:6f:5a:91;CMTS-MAC=00:01:5c:69:f8:46;CM-QOS=1.1;CM-VER=3.0;

 

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Expert

Re: Occasional T3 timeouts

The signal stats seem o/k but the error log entries indicate that something is going on. Perhaps there is noise ingress into the line(s) somewhere.

 

There are other signal stat figures 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 to see whether or not everything is in the green zone, see your node / cable plant and modem health, and also see a history plot for the modem. You should get a reply here in your topic. Good luck !

 



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Official Employee

Re: Occasional T3 timeouts

Hello @jh09c, thanks for reaching out to us on our Forums page! We appreciate you being a customer with us and I am sorry to hear about the connection issues you're experiencing. Thank you for posting your signal levels as well. We definitely want to further troubleshoot and look into this on our end. Can you please send me a Private Message including your first and last name as it appears on the account? 

 

To send me a Private Message, please click my name “ComcastAmira” and click “Send a message". 


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Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.
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Regular Visitor

Re: Occasional T3 timeouts

Thanks a bunch.