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Numerous connection dropouts a day over several months

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Frequent Visitor

Numerous connection dropouts a day over several months

Basic info:

- Equiment was a rented XFinity X1 modem.

- Internet connection loss anywhere from 1 to 10+ times a day since late October/early November.

- Only manually reconnecting one or both ends of coaxial cable would restore the connection.

- Switched out rented modem with Motorola MB8600 modem + TP-Link Archer C9 router, connection losses somewhat less frequent and now auto-reconnect after a period of time.

 

Since October/November I have been experiencing internet connection outages multiple times a day. I discovered that reconnecting one or both ends of the coaxial cable between wall outlet and X1 modem would temporarily resolve issue, usually for a few hours until another outage would occur. XFinity status showed no area-specific outages near me, and my neighbor's public-facing XFinity wifi has worked properly throughout the entire time.

 

At some point in late November, disconnecting the coaxial cable no longer always resolved the issue, and sometimes I just had to wait it out. I decided to try another modem/router setup (MB8600 modem + TP-Link Archer C9) to eliminate the possibility of a failing X1 modem.

 

Connection issues are still present, usually 1-5 times every 2 days. I no longer have to reconnect the coaxial cable since the modem eventually reestablishes connection after a few minutes/hours.

 

I have seen similar forum threads that suggest looking at the down/upstream power levels and Tx/Rx, but I am unsure where to access these levels using the Archer C9 (I don't see any down/upstream diagnostics on the router page 192.168.0.1). Assistance would be greatly appreciated, since this has been an extremely inconveniencing issue that has only been bearable because of my neighbor's public xfinitywifi connection.

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Expert

Re: Numerous connection dropouts a day for over a month

You don't get the signal stats from the router, you get them from your MB8600 cable modem.

 

 Get them here; http://192.168.100.1

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




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Re: Numerous connection dropouts a day for over a month

Ah, my apologies, you are correct. I had to disconnect the router prior to being able to access to modem directly. Here are the channel values:

 

Downstream bonded channels

   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB ) Corrected Uncorrected
   1 Locked QAM256 21 645 5.3 39.7 0 0
   2 Locked QAM256 1 525 5.5 41.7 0 0
   3 Locked QAM256 2 531 5.7 41.6 0 0
   4 Locked QAM256 3 537 5.9 41.7 0 0
   5 Locked QAM256 4 543 6.2 41.9 0 0
   6 Locked QAM256 5 549 6.4 41.9 0 0
   7 Locked QAM256 6 555 6.7 42.1 0 0
   8 Locked QAM256 7 561 6.9 42 0 0
   9 Locked QAM256 8 567 6.8 41.9 0 0
   10 Locked QAM256 9 573 6.2 41.6 0 0
   11 Locked QAM256 10 579 5.8 41.3 0 0
   12 Locked QAM256 11 585 5.6 41.2 0 0
   13 Locked QAM256 12 591 5.4 40.8 0 0
   14 Locked QAM256 13 597 5.5 40.5 0 0
   15 Locked QAM256 14 603 5.7 40.6 0 0
   16 Locked QAM256 15 609 5.4 40.3 0 0
   17 Locked QAM256 16 615 5.7 40.2 0 0
   18 Locked QAM256 17 621 5.7 40.2 0 0
   19 Locked QAM256 18 627 5.8 40 0 0
   20 Locked QAM256 19 633 5.5 40 0 0
   21 Locked QAM256 20 639 5.4 39.8 0 0
   22 Locked QAM256 22 651 5.4 39.8 0 0
   23 Locked QAM256 23 657 5.3 39.7 0 0
   24 Locked QAM256 24 663 5.5 39.9 0 0
   25 Locked QAM256 25 669 5.5 40 0 0
   26 Locked QAM256 26 675 5.6 39.2 0 0
   27 Locked QAM256 27 681 5.6 40.3 0 0
   28 Locked QAM256 28 687 5.8 40.1 0 0
   29 Locked QAM256 29 693 5.6 40.3 0 0
   30 Locked QAM256 30 699 5.8 40.5 0 0
   31 Locked QAM256 31 705 5.9 40.7 0 0
   32 Locked QAM256 32 711 5.9 40.8 0 0
   33 Locked OFDM PLC 159 805 5.7 38.5 0 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 36.5 42.8
   2 Locked SC-QAM 2 5120 30.1 43
   3 Locked SC-QAM 3 5120 23.7 43.8
   4 Locked SC-QAM 4 5120 17.3 44.3

 

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Expert

Re: Numerous connection dropouts a day for over a month

Everything is good. Please post the RF error / event log entries as well.



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Frequent Visitor

Re: Numerous connection dropouts a day for over a month

I've unfortunately had to factory reset the modem due to being unable to login after changing the default login.

I did however copy the first page (of many) of the event logs that occurred today when I grabbed the downstream/upstream values.

 

I've removed all MAC-related information:

 

Date Time Level Description
Wed Dec 11 2019 8:51:44 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;
Wed Dec 11 2019 8:51:57 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Wed Dec 11 2019 9:04:35 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;
Wed Dec 11 2019 9:07:16 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;
Wed Dec 11 2019 9:09:01 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Wed Dec 11 2019 9:09:11 Critical (3) No Ranging Response received - T3 time-out;
Wed Dec 11 2019 9:09:16 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Wed Dec 11 2019 9:09:39 Critical (3) No Ranging Response received - T3 time-out;
Wed Dec 11 2019 9:22:07 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;
Wed Dec 11 2019 10:40:41 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;
Wed Dec 11 2019 10:42:21 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Wed Dec 11 2019 10:42:37 Critical (3) No Ranging Response received - T3 time-out;
Wed Dec 11 2019 10:42:42 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Wed Dec 11 2019 10:43:07 Critical (3) No Ranging Response received - T3 time-out;
Wed Dec 11 2019 10:46:36 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;
Wed Dec 11 2019 10:48:20 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Wed Dec 11 2019 10:48:33 Critical (3) No Ranging Response received - T3 time-out;
Wed Dec 11 2019 10:48:36 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Wed Dec 11 2019 10:48:53 Critical (3) No Ranging Response received - T3 time-out;
Wed Dec 11 2019 11:01:21 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;
Wed Dec 11 2019 11:05:41 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;
Wed Dec 11 2019 11:07:27 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Wed Dec 11 2019 11:07:32 Critical (3) No Ranging Response received - T3 time-out;
Wed Dec 11 2019 11:07:41 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
Wed Dec 11 2019 11:08:10 Critical (3) No Ranging Response received - T3 time-out;
Wed Dec 11 2019 11:11:57 Critical (3) Resetting the cable modem due to docsDevResetNow
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
Wed Dec 11 2019 11:13:44 Warning (5) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;
Wed Dec 11 2019 11:13:44 Warning (5) Dynamic Range Window violation
Wed Dec 11 2019 11:25:41 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;
Wed Dec 11 2019 11:25:46 Critical (3) No Ranging Response received - T3 time-out;
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Expert

Re: Numerous connection dropouts a day for over a month

Even though the signal stats looked o/k at that snapshot in time, the error log entries confirm that something is going on (loss of sync). 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 can check the CMTS (Cable Modem Termination System) 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 !



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Official Employee

Re: Numerous connection dropouts a day for over a month

Greetings, @Just_A_Customer! I appreciate you taking the time to reach out to us here on the forums. I hope you are having an amazing day. I apologize to hear of the issues you are having with your internet dropping out as often as it does. As EG mentioned, there certainly looks like something could be going on with the signal that we can certainly have a look at. Can you please send me a PM with your first and last name so I may further assist you?

 

To send a private message, please click my name "ComcastMichael" then select "Send a Message" on the right side.


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Re: Numerous connection dropouts a day for over a month

I'm following up on this to report the issue was never resolved.

 

The tech came out and replaced the some/all of the cabling outside (hard to tell). They weren't informed on what was going on, and when I tried to explain I was basically ignored. At any rate, we had seemingly interruption-free internet for about a week or two.

 

Since then (it's been almost 3 months), our connection has been dropping AT LEAST once or twice every day, up to many times. Half the time it auto-reconnects (which can take a while), while the other half we have to manually disconnect the modem several times to get it to reconnect.

 

I have tried using both the Xfinity-provided modem and my own, and each are encountering the issues. I've even tried a different coaxial hookup in a different room to verify it wasn't just a single bad connection.

 

This is getting beyond irritating, and at this point it's nearly almost been half a year of daily internet disruptions.

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Frequent Visitor

Re: Numerous connection dropouts a day for over a month

One more follow-up:

 

I coordinated with ComcastMichael and got another tech scheduled out a few weeks ago. They replaced a lot of the existing cabling outside, installed a dedicated little housing for the new connection, and replaced some of the coaxial outlet inside the house. One thing to note about my particular case - there was a previous DishTV cable hookup on the house, which might have been causing some of the issues.

 

So far since the 2nd tech came out, there has not been a single distruption bar a quick dis-and-reconnect within an hour or two of the visit.

 

I'm hoping that this is finally resolved and can be chalked up to poor/improper existing cabling or weather damage.

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Official Employee

Re: Numerous connection dropouts a day for over a month

I'm glad I was able to assist you with getting these internet dropouts figured out, @Just_A_Customer. If you ever need further assistance don't hesitate to reach out to us.


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Expert

Re: Numerous connection dropouts a day for over a month

So what was the final solution ? @ComcastMichael and @Just_A_Customer  ? Wouldn't it benefit more customer readers here if it was made public without locking this thread  ??? Isn't that what these forums are for ???



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