Connectivity and managing Your Comcast Business network
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Intermittent Connectivity in mornings and then again at night


Intermittent Connectivity in mornings and then again at night

For the past few weeks we have been getting kicked from the internet between 9-11 am and 7-10pm at night. At first the internet would go dead for everyone, no network available. After unplugging the cable modem it became less frequent, but we still got the lag during the same times that would kick us out of your apps/websites. I have noticed last night that 2 of the upstreams were not reporting data and today I see one not showing data. When this happens i see a lot of errors in the cable modem event logs.  From about 11:30 to about 7 pm we dont see any issues if any. Here is my information and logs:


Cable Modem specs:

9-21-2019 1-12-36 PM.png


State Information:

9-21-2019 1-14-02 PM.png

Current Upstream Information:

-- currently showing all upstreams up. Freq have been this value pretty steady. more logs below on what it looks like with outage.

9-21-2019 1-15-24 PM.png

Current Downstream:


9-21-2019 1-18-03 PM.png

Current Event Logs:

9-21-2019 1-19-36 PM.png


State Of Modem At Night when issue starts:


I saw 2 of the Upstreams down then one down as the night progresses. The Upstream 2 stays down maybe all night, was still down this morning.


9-20-2019 8-03-599 PM.png


Then later it is just upstream 2 that is not reporting for most of the night i am assuming since in the morning it was still not getting information on this log.


9-20-2019 8-29-04 PM.png


What I noticeds is that when the network goes "down" it appears to be the cablem modem restarting and I see a sync error in the log that normally isnt there. When the Upstream 2 is not displaying information I see the two log messages:


"Unicast Ragning Received Abort Reponse - initializing AND No Rangin Respone recieived - T3 time-out"


But upon cable reboots (not done by me) it shows the "SYNC Timing Synchronization failure - Loss of Sync"


9-21-2019 11-31-04 AM.png


Sync entry shows up on automatic reboots of cable modem


9-21-2019 11-34-10 AM.png


Trouble Shooting thus far:


1. Disconnected all wired devices to modem except one pc with direct cable connect to modem.

2. Disconnected power cable for more than 30 seconds on cable modem.

3. Visually checked outside cable where exposed and didnt see anything, most of its underground. 


Next step:

3. Turn off Wifi and disconnect all wired devices again


What I have read:

1. Upstreams may have SNR high maybe causing the issue.

2. Upstream data that is missing is being turned off by comcast for maintenance?



Community Manager
Community Manager

Re: Intermittent Connectivity in mornings and then again at night

Thank you so much for taking the time to reach out to us through our business forums. I would love to assist with the connectivity issues and get to the bottom of this with you. Can you please reach out through private message with your first and last name, full service address and account number or phone number and we will get started? 


Re: Intermittent Connectivity in mornings and then again at night

Chris came out today. I showed him the log information and summaries I have provided here on the forums. He didnt see any noise coming from inside the house. He tightened all the lines from the house to the box. He did mention the neighboors cable was "finger" tightened and he tightened them all. He noiced that the Power level on the upstreams go above 54 dbmv then you would get noise and the upstreams would faile. By tightening the cables outside seem to have lowered all Power on the upstream to 41.25 dbmv and I also dont see any Uncorrectables or correcteds in the downstreams like I had before. He gave me his card and said if it happens again text him and he would get with his manager and do a "sweep". Ill keep you posted. It goes out at night also so tonight will be a good test.9-25-2019 10-05-51 AM.png9-25-2019 10-05-13 AM.png

Community Manager
Community Manager

Re: Intermittent Connectivity in mornings and then again at night

Thanks for the update! How has service been? How are the logs looking?



Occasional Visitor

Re: Intermittent Connectivity in mornings and then again at night

I have had the same issue and made a similar post. The community service was not going to schedule a technician to come look until I worked up a fuss... I shouldn’t have to. But it’s occurred worse in the evenings now making it almost unuseable.