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Help - dropping upstream connection

Regular Visitor

Help - dropping upstream connection

For about a year my internet has been going out on a near daily basis. Over the last few months, it’s been getting worse, cutting out once every couple hours. I’ve replaced the connector at the faceplate, the splitter, and all cables, which have made no difference. I called up Comcast and they replaced the line from my house to the street, but that didn’t seem to help either. I looked into the modem logs and there seem to be a number of errors.

“Unicast DSID PSN startup error” and “Started Unicast Maintenance Ranging - No Response received” are the two that seem to pop up right before the internet goes down. I did a bit of googling and it seems those are related to upstream issues. Checking the modem when the connection goes down, all the downstreams look fine, but the upstreams are usually “Not Locked”.

Wondering if there is anything else I can try on my end before I pay someone to come out and take a look?
Expert

Re: Help - dropping upstream connection

What do the modem's signal stats look like ? Try getting them here http://192.168.100.1 or here http://10.0.0.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

What is the exact make and model number of the modem ?




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Regular Visitor

Re: Help - dropping upstream connection

Downstream is >6 dBmV with ~39 dB SNR on all channels. Upstream is 38.5 dBmV on all channels, and my router does not give SNR for upstream. When the internet cuts out, power for upstreams drops to 0. Model is Netgear CM500-100NAS.
Expert

Re: Help - dropping upstream connection

O/k, please post the error / event log entries as well.



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Regular Visitor

Re: Help - dropping upstream connection

Recent entries in the log. Changed the MAC address a bit.

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:00:xx:xx;CMTS-MAC=00:87:31:91:xx:xx;CM-QOS=1.1;CM-VER=3.0;
2019-7-7, 17:30:09 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:00:xx:xx;CMTS-MAC=00:87:31:91:xx:xx;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:49 Notice (6) Honoring MDD; IP provisioning mode = IPv6
1970-1-1, 00:00:27 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:00:xx:xx;CMTS-MAC=00:87:31:91:xx:xx;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:21 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:00:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2019-7-7, 17:28:14 Critical (3) Resetting the cable modem due to docsDevResetNow
1970-1-1, 00:02:11 Critical (3) TFTP Request Retries exceeded, CM unable to register
1970-1-1, 00:02:11 Critical (3) TFTP failed - Request sent - No Response;CM-MAC=14:59:c0:00:xx:xx;CMTS-MAC=00:87:31:91:xx:xx;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:27 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:00:xx:xx;CMTS-MAC=00:87:31:91:xx:xx;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:21 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:00:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2019-7-7, 17:10:52 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:00:xx:xx;CMTS-MAC=00:87:31:91:xx:xx;CM-QOS=1.1;CM-VER=3.0;
Regular Visitor

Re: Help - dropping upstream connection

Any thoughts?
Official Employee

Re: Help - dropping upstream connection

Hi there, Camhabib. 

 

I can take a look at your modem from our side and help get this resolved for you. 

 

Can you please private message me your full name? Thank you for posting to our forums. 
To send a private message, please click my name "ComcastMartin" then select "Send a Message" on the right side.

 

Thank you for being a valued Comcast customer as well! 


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Expert

Re: Help - dropping upstream connection

Yep. The log entries show that the modem is indeed losing block synch with the CMTS / system. You are in good hands now !  Good luck with it !



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Official Employee

Re: Help - dropping upstream connection

Hi, Camhabib. 

 

I wanted to touch base one more time before closing out your post. Did you have any other questions? 


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Official Employee

Re: Help - dropping upstream connection

I am closing this post out due to inactivity. 

 

If you have any other questions, please feel free to reach out to us on the forums again!

 

Thank you for being a Comcast customer! Take care! 


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