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Visitor

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3 Messages

Wednesday, March 29th, 2023 12:54 AM

Closed

Frequent Issues since early March

Since early March, I've been having frequent dips in the quality of service, and several instances of it cutting out completely. The last week or so it seems to have only been getting worse. I'm currently subscribed to a 1200mb/s plan, but have frequent dips into the low 100-200kb/s. They're usually brief, being only 5 minutes or so at a time, but it's extremely disruptive. I've tried mostly everything I can think of on my end to try to improve things to no avail. I've done all of the following:

-Restarted and power cycled my equipment (PC, router, modem)

-Tested other wired devices in the house

-Factory reset both the router and modem

-Connected directly from the modem to my pc

-Purchased a new Docsis 3.1 modem (arris s33)

Looking at the modem's web ui, I see that one of the bands has tons of corrections. Band 29 currently has 132720084 corrections and goes up every time I check it. Is there anything else I can do, or is this likely a problem with the lines outside my house.

Visitor

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3 Messages

2 years ago

Here is the latest screenshot of the dashboard for the modem.

Expert

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110.3K Messages

2 years ago

The power level values and the SNR's are OK as long as they are remaining stable. Channel 29 is the OFDM channel. It is a very wide bandwidth channel that packs a lot of data within. Due to that fact, seeing a large number of corrected errors is normal. The FEC (Forward Error Correction) circuitry / system is doing its job. All of those errors are *corrected* ones. There are zero *uncorrected* errors. 

Are there any modem RF error log entries being shown ? If so, please post them as well in their entirety (copy and paste them, don't post a screenshot) but redact the CM MAC and the CMTS MAC addresses for your privacy. They are considered to be personal information. The posting of personally identifying information is a violation of their forum guidelines. The forum bot will not allow your post to be seen publically.

Visitor

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3 Messages

@EG​ Thanks for the response! Here's the error log with the addresses removed:

31/12/1969
19:00:19 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:01:33 3 Successful LAN WebGUI login from 192.168.100.10 on 70/01/01 at 12:01 AM.
31/12/1969
19:01:57 3 Successful LAN WebGUI login from 192.168.100.10 on 70/01/01 at 12:02 AM.
31/12/1969
19:02:20 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:02:29 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:02:35 3 No Ranging Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:16 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
31/12/1969
19:00:18 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:20 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-9, 42MHz.
31/12/1969
19:00:23 3 No Ranging Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:38 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
31/12/1969
19:00:38 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
31/12/1969
19:00:38 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
28/3/2023
10:40:27 3 Successful LAN WebGUI login from 73.215.224.159 on 23/03/28 at 10:40 AM.
31/12/1969
19:00:16 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
31/12/1969
19:00:20 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:21 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-9, 42MHz.
31/12/1969
19:00:23 3 No Ranging Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:34 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
31/12/1969
19:00:34 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
31/12/1969
19:00:34 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
28/3/2023
10:44:25 3 Successful LAN WebGUI login from 73.215.224.159 on 23/03/28 at 10:44 AM.
28/3/2023
11:09:02 3 Successful LAN WebGUI login from 73.215.224.159 on 23/03/28 at 11:09 AM.
31/12/1969
19:00:15 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
31/12/1969
19:00:19 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:20 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-9, 42MHz.
31/12/1969
19:00:23 3 No Ranging Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:37 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
31/12/1969
19:00:37 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
31/12/1969
19:00:37 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
28/3/2023
11:11:11 3 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
18:19:38 3 Successful LAN WebGUI login from 73.215.224.159 on 23/03/28 at 6:19 PM.
31/12/1969
19:00:16 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
31/12/1969
19:00:20 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:22 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-9, 42MHz.
31/12/1969
19:00:25 3 No Ranging Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:38 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
31/12/1969
19:00:38 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
31/12/1969
19:00:38 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
28/3/2023
18:22:48 3 Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
18:23:36 3 Successful LAN WebGUI login from 73.215.224.159 on 23/03/28 at 6:23 PM.
28/3/2023
19:15:35 3 Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
19:30:22 3 Successful LAN WebGUI login from 73.215.224.159 on 23/03/28 at 7:30 PM.
28/3/2023
22:10:39 3 Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:13:38 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:13:45 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:16:33 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:16:33 3 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:16:34 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:16:34 3 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:17:13 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:17:13 3 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:21:36 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:31:44 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-9, 42MHz.
28/3/2023
22:31:57 3 No Ranging Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:32:16 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
28/3/2023
22:32:16 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
28/3/2023
22:32:16 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
28/3/2023
22:32:22 3 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
28/3/2023
22:32:26 3 No Ranging Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
29/3/2023
04:57:17 3 Successful LAN WebGUI login from 73.215.224.159 on 23/03/29 at 4:57 AM.
29/3/2023
07:38:56 3 Successful LAN WebGUI login from 73.215.224.159 on 23/03/29 at 7:38 AM.
31/12/1969
19:00:16 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
31/12/1969
19:00:19 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:22 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-9, 42MHz.
31/12/1969
19:00:26 3 No Ranging Response received - T3 time-out;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
31/12/1969
19:00:28 6 Honoring MDD; IP provisioning mode = IPv6
31/12/1969
19:00:37 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
31/12/1969
19:00:37 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
31/12/1969
19:00:37 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
29/3/2023
07:48:32 6 DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=[Personal Info];CMTS-MAC=[Personal Info];CM-QOS=1.1;CM-VER=3.1;
29/3/2023
07:49:19 3 Successful LAN WebGUI login from 192.168.100.10 on 23/03/29 at 7:49 AM.
29/3/2023
10:38:58 3 Successful LAN WebGUI login from 73.215.224.159 on 23/03/29 at 10:38 AM.

Retired Employee

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729 Messages

Please send us a Direct message with your name and address. We will be happy to check all the signals going into your home. Thanks! 

Expert

 • 

110.3K Messages

2 years ago

OK so even though the signal status values looked OK at that snapshot in time, the error log entries confirm that something is going on. Perhaps there is noise ingress into the line(s) / an upstream channel / return path impairment somewhere.


There are other signal stat values 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 (The Digital Care Team) who are available to these boards. They will be able to poll the CMTS (Cable Modem Termination System) to check 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 the CMTS for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !

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