Frequent Visitor
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8 Messages
Frequent internet drops daily
Equipment:
- Arris SB6141 Cable Modem
- Linksys AC1900 Router
- Modem is connected directly to exterior box - no splitters - just a single coupler between the Comcast-provided coax cable and the Comcast-terminated service line
We have been having multiple failures to reach the internet each day. Each instance lasts about 10-15 seconds, and they can occur several times an hour. This is a real issue for the modern world.
The issue appears to be with the cable modem connection. I have connected a single laptop to the modem and logged pings to 8.8.8.8 overnight. Several periods of unreachability occured each time.
I'm not entirely sure which screens are most useful from my cable modem console, but the following log seems relevant. In fact, I found this forum by googling the verbose errors.
| May 27 2020 10:00:52 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 10:00:12 | 3-Critical | R05.0 | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:59:52 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:59:52 | 3-Critical | R05.0 | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:59:32 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:58:52 | 3-Critical | R05.0 | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:58:33 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:58:32 | 3-Critical | R05.0 | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:58:13 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:57:33 | 3-Critical | R05.0 | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:57:13 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:57:13 | 3-Critical | R05.0 | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:56:53 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:56:13 | 3-Critical | R05.0 | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:55:53 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:55:53 | 3-Critical | R05.0 | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:55:33 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:54:53 | 3-Critical | R06.0 | Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:54:53 | 3-Critical | R03.0 | Ranging Request Retries exhausted;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
| May 27 2020 09:54:33 | 3-Critical | R04.0 | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:06:07:d4;CMTS-MAC=5c:83:8f:06:85:5b;CM-QOS=1.1;CM-VER=3.0; |
SevenLions
Frequent Visitor
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8 Messages
5 years ago
Please let me know what additional logs or configuration parameters would be useful, and if there are other steps I should take.
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SevenLions
Frequent Visitor
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8 Messages
5 years ago
Thanks, EB. Here is a screenshot of those numbers. I may be moderated, so I will also follow up with a paste-in of the table.
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EG
Expert
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111.5K Messages
5 years ago
Please also post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.
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SevenLions
Frequent Visitor
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8 Messages
5 years ago
As suspected, my images got moderated. So here it is in text form.
[1] 32QAM
[3] 64QAM
[1] 16QAM
[3] 64QAM
[1] 16QAM
[3] 64QAM
[1] 32QAM
[3] 64QAM
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EG
Expert
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111.5K Messages
5 years ago
The signal stats are o/k but the error log entries indicate that something is going on. 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 will be able to poll the CMTS to see whether or not everything is in the green zone, see your node / cable plant and modem health, and also see a history plot for the modem. You should get a reply here in your topic. Good luck !
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EG
Expert
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111.5K Messages
5 years ago
Quite welcome !
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XfinityJoeTru
Official Employee
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7K Messages
5 years ago
Hi SevenLions. We welcome you to the Xfinity Forums and thank you for creating your first post. I can assist with further troubleshooting your intermittent connectivity issues. In order to have a better insight, I will have to poll the CMTS for real-time and historical RF signal reports from your modem, and check your local Node/Plant for signal degradation / errors. Please send me a private message and include your full name so I can access your equipment. To send a private message: click my name (ComcastJoeTru) to view my profile. Then click the link that says "Send a message" and there you can private message me.
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SevenLions
Frequent Visitor
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8 Messages
5 years ago
Thanks, @EG . Here's hoping!
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ty-baloo
New Poster
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1 Message
5 years ago
I'm also having this exact issue. Been through 2 of the Xfinity Gateways and used with a separate router and without. Talked to tech support around 5 times since i started my service (less than 2 months since i started it)
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SevenLions
Frequent Visitor
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8 Messages
5 years ago
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