S

Visitor

 • 

4 Messages

Thu, Jul 22, 2021 6:36 PM

Frequent Disconnects and Signal Power Issues

I have been experiencing random disconnects on a regular basis for a couple weeks now and am at wits end.  I have called in to xfinity customer support multiple times only to have them tell me they cannot do anything because I do not rent a proprietary modem from them.  I know the issue I am having is not due to my modem, but cannot get a tech scheduled to my property to investigate the situation.  Please help!  I am considering cancelling my service and trying to go with a different ISP as I cannot receive any assistance resolving the issue.

I have been reading a few posts about similar issues to my own, and in those cases the users were asked to provide some statistics from their modem.  I have noticed persistent errors labelled "Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T3 or T4 timeout" in my modems event log.

Procedure Status Comment
Acquire Downstream Channel 579000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD honorMdd(4)
 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 29 579000000 Hz 4.8 dBmV 40 dB 0 0
2 Locked QAM256 30 585000000 Hz 4.5 dBmV 39.9 dB 0 0
3 Locked QAM256 31 591000000 Hz 4 dBmV 39.7 dB 0 0
4 Locked QAM256 32 597000000 Hz 4.1 dBmV 39.7 dB 0 0
5 Locked QAM256 33 603000000 Hz 3.8 dBmV 39.7 dB 0 0
6 Locked QAM256 34 609000000 Hz 3.5 dBmV 39.5 dB 0 0
7 Locked QAM256 35 615000000 Hz 3.8 dBmV 39.7 dB 0 0
8 Locked QAM256 36 621000000 Hz 3.2 dBmV 39.4 dB 0 0
9 Locked QAM256 37 627000000 Hz 3.6 dBmV 39.4 dB 0 0
10 Locked QAM256 38 633000000 Hz 3.8 dBmV 39.6 dB 0 0
11 Locked QAM256 39 639000000 Hz 3.3 dBmV 39.4 dB 0 0
12 Locked QAM256 40 645000000 Hz 3.8 dBmV 39.5 dB 0 0
13 Locked QAM256 41 651000000 Hz 3.5 dBmV 39.4 dB 0 0
14 Locked QAM256 42 657000000 Hz 2.9 dBmV 39.1 dB 0 0
15 Locked QAM256 43 663000000 Hz 3.6 dBmV 39.3 dB 0 0
16 Locked QAM256 44 669000000 Hz 3.1 dBmV 39.1 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 35600000 Hz 47.8 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 29200000 Hz 49.5 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 22800000 Hz 51 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 16400000 Hz 52 dBmV

Event Reports:

Time Priority Description
2021-7-21, 19:45:19 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-
2021-7-21, 19:41:01 Warning (5) Dynamic Range Window violation
2021-7-21, 19:41:00 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-
2021-7-21, 19:40:57 Warning (5) Dynamic Range Window violation
2021-7-21, 19:40:57 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-
2021-7-21, 19:40:48 Warning (5) Dynamic Range Window violation
2021-7-21, 19:40:47 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-
2021-7-21, 19:40:46 Warning (5) Dynamic Range Window violation
2021-7-21, 19:37:54 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2021-7-21, 19:37:47 Critical (3) No Ranging Response received - T3 time-out;CM-
2021-7-21, 19:37:34 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-
2021-7-21, 19:31:48 Warning (5) Dynamic Range Window violation
2021-7-21, 14:59:46 Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 14:44:40 Notice (6) WiFi Interface [wl0] set to Channel 1 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 13:26:41 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2021-7-21, 13:26:22 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-
2021-7-21, 13:22:06 Warning (5) Dynamic Range Window violation
2021-7-21, 13:20:32 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-
2021-7-21, 13:14:11 Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 12:59:24 Warning (5) Dynamic Range Window violation
2021-7-21, 12:59:05 Notice (6) WiFi Interface [wl0] set to Channel 6 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 12:13:49 Warning (5) Dynamic Range Window violation
2021-7-21, 12:13:49 Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 11:58:55 Warning (5) Dynamic Range Window violation
2021-7-21, 11:58:42 Notice (6) WiFi Interface [wl0] set to Channel 1 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 11:13:39 Warning (5) Dynamic Range Window violation
2021-7-21, 11:13:27 Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 10:58:26 Warning (5) Dynamic Range Window violation
2021-7-21, 10:58:22 Notice (6) WiFi Interface [wl0] set to Channel 1 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 09:51:01 Warning (5) Dynamic Range Window violation
2021-7-21, 09:50:52 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-
2021-7-21, 09:30:14 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2021-7-21, 09:29:56 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-
2021-7-21, 09:25:35 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-
2021-7-21, 06:42:10 Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 06:27:02 Notice (6) WiFi Interface [wl0] set to Channel 6 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 06:11:54 Notice (6) WiFi Interface [wl0] set to Channel 1 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 05:56:46 Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-21, 05:41:40 Notice (6) WiFi Interface [wl0] set to Channel 6 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2021-7-20, 19:45:00 Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INTERFERENCE

Responses

Visitor

 • 

4 Messages

2 m ago

Update: I was able to catch the cable power levels just after the disconnect event and they show upstream at substantially lower levels then the last time:

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 29 579000000 Hz 4.8 dBmV 40.1 dB 0 0
2 Locked QAM256 30 585000000 Hz 4.6 dBmV 40 dB 0 0
3 Locked QAM256 31 591000000 Hz 4 dBmV 39.9 dB 0 0
4 Locked QAM256 32 597000000 Hz 4.2 dBmV 39.9 dB 0 0
5 Locked QAM256 33 603000000 Hz 3.8 dBmV 39.8 dB 0 0
6 Locked QAM256 34 609000000 Hz 3.5 dBmV 39.7 dB 0 0
7 Locked QAM256 35 615000000 Hz 3.9 dBmV 39.8 dB 0 0
8 Locked QAM256 36 621000000 Hz 3.2 dBmV 39.6 dB 0 0
9 Locked QAM256 37 627000000 Hz 3.6 dBmV 39.5 dB 0 0
10 Locked QAM256 38 633000000 Hz 3.8 dBmV 39.7 dB 0 0
11 Locked QAM256 39 639000000 Hz 3.3 dBmV 39.5 dB 0 0
12 Locked QAM256 40 645000000 Hz 3.7 dBmV 39.6 dB 0 0
13 Locked QAM256 41 651000000 Hz 3.4 dBmV 39.5 dB 0 0
14 Locked QAM256 42 657000000 Hz 2.9 dBmV 39.3 dB 0 0
15 Locked QAM256 43 663000000 Hz 3.5 dBmV 39.5 dB 0 0
16 Locked QAM256 44 669000000 Hz 3 dBmV 39.2 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 35600000 Hz 37.5 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 29200000 Hz 37.3 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 22800000 Hz 36 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 16400000 Hz 35.3 dBmV
EG

Expert

 • 

89K Messages

2 m ago

See if any of these self troubleshooting tips apply first;

The upstream power is on the high side and it may be intermittently fluctuating even higher to out of spec levels (it's already out of spec on channels 3 & 4). That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, kinks, sharp bends, etc.

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.

Visitor

 • 

4 Messages

@EG Thank you for the tips!  I will look into upgrading my coax cable and connections.  What I can accomplish is limited as I have an apartment building, and I currently have no splitters in my unit, but cannot say what kind of nonsense may be happening in the rest of the building.  Your help is very much appreciated!

EG

Expert

 • 

89K Messages

Good luck with it ! Multiple dwellings are typically known to be more problematic for coax cable based ISP's....

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

Official Employee

 • 

220 Messages

Wow, I can’t imagine the frustration you must be feeling @Shawn_9322 . Expert @EG has provided spot on information. Our team would also be happy to attempt some additional troubleshooting as well if needed. We certainly would hate to lose a fantastic customer. Working together we will get to the bottom of this. 


If you are still running into problems after trying the suggestions mentioned, please send us a private message with your full name, name of account holder (if different) and service address? To send a private message, please click the chat icon next to the bell in the upper right corner. Click the “notepad and pen” button. Send the full message to our shared support handle “Xfinity Support”. We look forward to hearing from you!  

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
ruebee

New Poster

 • 

18 Messages

@Shawn_9322 Any luck with your problem? I'm having a similar issue.

Official Employee

 • 

2.9K Messages

Hello @ruebee. If you are having troubles and need support, please create a new topic of your own here on this board detailing your issue so that the community and our support representatives can assist.

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

New to the Community?

Start Here