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Internet Keeps Dropping

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Frequent Visitor

Internet Keeps Dropping

My devices stay connected to the WiFi network, but the Internet goes out constantly, and even devices that are wired to the modem/router lose connection. This happens multiple times a day, and seems to happen more every day. Over the past 3 going on 4 months, I have been on multiple chats, calls, and even had an Xfinity technician out here once. The technician did not enter the home due to their current restrictions with the pandemic, but he said he fixed everything outside, replaced cables and tightened connections all the way to the street. I've called Netgear, but anything they had me try didn't help. I have even upgraded my speed package, which Xfinity said would ultimately fix the connectivity issues. But it hasn't, so I am paying more for what feels like the same thing. 😞 I will post the event log and upstream/downstream info here meantime. Hope someone can help me out.
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Frequent Visitor

Re: Internet Keeps Dropping

2020-06-10, 08:07:59.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 08:03:51.0 Warning (5) MDD message timeout;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 08:02:50.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2020-06-10, 08:02:42.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
2020-06-10, 08:02:38.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
2020-06-10, 08:02:20.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 07:58:00.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 07:57:37.0 Warning (5) MDD message timeout;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 07:56:40.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2020-06-10, 07:56:30.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
2020-06-10, 07:56:27.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
2020-06-10, 07:56:09.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 07:55:37.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 07:54:35.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2020-06-10, 07:54:28.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
2020-06-10, 07:54:22.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
2020-06-10, 07:54:08.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 07:49:44.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 07:46:27.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2020-06-10, 07:46:22.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
2020-06-10, 07:46:15.0 Notice (6) Received REG-RSP while in REG-HOLD1 state;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-06-10, 07:46:12.0 Warning (5) Dynamic Range Window violation
2020-06-10, 07:22:10.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 07:19:46.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-10, 01:40:26.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-09, 22:21:58.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-09, 22:21:58.0 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
2020-06-09, 22:21:58.0 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.1;CM-VER=3.0;
Time Not Established Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
Time Not Established Critical (3) No Ranging Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out;CM-MAC=38:94:ed:e8:1c:50;CMTS-MAC=00:01:5c:62:da:61;CM-QOS=1.0;CM-VER=3.0;
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Frequent Visitor

Re: Internet Keeps Dropping


Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 8 447000000 Hz -4.0 dBmV 35.9 dB 18 84
2 Locked QAM256 9 453000000 Hz -3.4 dBmV 36.5 dB 0 0
3 Locked QAM256 10 459000000 Hz -3.6 dBmV 36.3 dB 0 0
4 Locked QAM256 11 465000000 Hz -4.7 dBmV 35.4 dB 20 70
5 Locked QAM256 12 471000000 Hz -5.8 dBmV 34.5 dB 140 60
6 Locked QAM256 13 477000000 Hz -5.8 dBmV 34.4 dB 132 137
7 Locked QAM256 14 483000000 Hz -4.6 dBmV 35.3 dB 93 60
8 Locked QAM256 15 489000000 Hz -3.5 dBmV 35.9 dB 73 1
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 17300000 Hz 34.8 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 23700000 Hz 35.3 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 30300000 Hz 36.0 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 36700000 Hz 36.3 dBmV
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Frequent Visitor

Re: Internet Keeps Dropping

Lots of views but not seeing any responses? Help please?
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Expert

Re: Internet Keeps Dropping

The downstream power is on the low side, and so are the SNR's. and they may be intermittently fluctuating even lower to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.



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Official Employee

Re: Internet Keeps Dropping

Greetings, @tlcondor! 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 running into when it comes to the internet. I work from home myself and certainly understand the importance of a reliable connection. I would like to have a closer look at the signal and see what could be going on. Since you already sent a PM, I will continue to assist you through there.


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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.
Was your question answered? Mark the post as Best Answer!
Frequent Visitor

Re: Internet Keeps Dropping

Thanks for the reply. Xfinity tech came out and sized everything outside the house. No splitters inside, but I will go through all again to refresh, check and clean off. If that doesn't work I guess it's back to calling Xfinity multiple times till they send another tech. They keep telling me tho, that due to COVID 19 they cannot enter the home. So does that mean I'm out of luck??
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Frequent Visitor

Re: Internet Keeps Dropping

I thought I would update this in case it helps others with similar issues... the Xfinity technician came this morning and he was the same technician who came out last week. He didn't think there was much more he could do, everything seemed to be tight and good, and he had replaced any old parts between the house and the tap last week. But he did run signal tests from the tap to the home, and vice versa, and he also capped a port (or something like that) that was uncovered at the tap. He didn't think that would make much of a difference, but since he did that, there have been no disconnects or event log errors! So I am hopeful that seemingly minor fix did the trick. Thank you and the Xfinity technician and @ComcastMichael for all your help.