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Started Unicast Maintenance Ranging - No Response received - T3 time-out
We have been experiencing random internet outages for the past couple of months. On Sunday, I took the time to reset our Motorola Cable Modem Model: MT7711, so I could look at the Event Log and look the upstream power (Pwr) and signal to noise (SNR) values for the downstream and upstream bonded channels.
I noticed multiple T3 error messages in the Event Log and saw upstream Pwr values that were too high (around 54 dBmV). I read that this issue was likely caused by the long length of coax cable and the splitter for the of the cable modem and cable tv box. So, I moved the cable modem to the other side of the basement where the coax cable enters the house and the upstream Pwr values decreased to the 44 dBMV range. I then added the splitter at the location where the coax cable comes into the basement. After adding the splitter, the T3 errors did not occur and the upstream Pwr values stayed in the 44 dBvM range.
However, another internet outage occurred the next day and I saw the following error message in the Event Log error (while the upstream Pwr values were still good):
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0;
I need help finding out why the internet outages are still occurring.
The current Event Log is:
| Time | Priority | Description |
| Time Not Established | Notice (6) | Honoring MDD; IP provisioning mode = IPv6 |
| Mon Jul 17 08:17:44 2023 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Time Not Established | Notice (6) | Honoring MDD; IP provisioning mode = IPv6 |
| Mon Jul 17 16:30:55 2023 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
The current downstream and upstream values:
Downstream
| Channel | Lock Status | Modulation | Channel ID | Freq. (MHz) | Pwr (dBmV) | SNR (dB) | Corrected | Uncorrected |
| 1 | Locked | QAM256 | 28 | 579.0 | 1.6 | 43.5 | 0 | 0 |
| 2 | Locked | QAM256 | 21 | 537.0 | 1.4 | 42.6 | 0 | 0 |
| 3 | Locked | QAM256 | 22 | 543.0 | 1.5 | 42.8 | 0 | 0 |
| 4 | Locked | QAM256 | 23 | 549.0 | 1.5 | 42.9 | 0 | 0 |
| 5 | Locked | QAM256 | 24 | 555.0 | 1.5 | 43.0 | 0 | 0 |
| 6 | Locked | QAM256 | 25 | 561.0 | 1.4 | 43.1 | 0 | 0 |
| 7 | Locked | QAM256 | 26 | 567.0 | 1.4 | 43.2 | 0 | 0 |
| 8 | Locked | QAM256 | 27 | 573.0 | 1.5 | 43.3 | 0 | 0 |
| 9 | Locked | QAM256 | 29 | 585.0 | 1.9 | 43.7 | 0 | 0 |
| 10 | Locked | QAM256 | 30 | 591.0 | 2.2 | 43.8 | 0 | 0 |
| 11 | Locked | QAM256 | 31 | 597.0 | 2.3 | 43.8 | 0 | 0 |
| 12 | Locked | QAM256 | 32 | 603.0 | 2.5 | 43.8 | 0 | 0 |
| 13 | Locked | QAM256 | 33 | 609.0 | 2.7 | 43.9 | 0 | 0 |
| 14 | Locked | QAM256 | 34 | 615.0 | 2.9 | 44.1 | 0 | 0 |
| 15 | Locked | QAM256 | 35 | 621.0 | 3.1 | 44.1 | 0 | 0 |
| 16 | Locked | QAM256 | 36 | 627.0 | 3.4 | 44.3 | 0 | 0 |
| 17 | Locked | QAM256 | 37 | 633.0 | 3.9 | 45.9 | 0 | 0 |
| 18 | Locked | QAM256 | 38 | 639.0 | 4.1 | 46.3 | 0 | 0 |
| 19 | Locked | QAM256 | 39 | 645.0 | 4.2 | 46.0 | 0 | 0 |
| 20 | Locked | QAM256 | 40 | 651.0 | 4.3 | 46.4 | 0 | 0 |
| 21 | Locked | QAM256 | 41 | 657.0 | 4.3 | 45.9 | 0 | 0 |
| 22 | Locked | QAM256 | 42 | 663.0 | 4.5 | 46.5 | 0 | 0 |
| 23 | Locked | QAM256 | 43 | 669.0 | 4.5 | 45.9 | 0 | 0 |
| 24 | Locked | QAM256 | 44 | 675.0 | 4.6 | 46.2 | 0 | 0 |
| Total | 0 | 0 |
Upstream
| 1 | Locked | ATDMA | 2 | 5120 | 22.8 | 44.3 |
| 2 | Locked | ATDMA | 1 | 5120 | 16.4 | 44.2 |
| 3 | Locked | ATDMA | 3 | 5120 | 29.2 | 44.2 |
| 4 | Locked | ATDMA | 4 | 5120 | 35.6 | 44.2 |
| 5 | Not Locked | Unknown | 0 | 0 | 0 | 0.0 |
| 6 | Not Locked | Unknown | 0 | 0 | 0 | 0.0 |
| 7 | Not Locked | Unknown | 0 | 0 | 0 | 0.0 |
| 8 | Not Locked | Unknown | 0 | 0 | 0 | 0.0 |
Accepted Solution
EG
Expert
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112.2K Messages
2 years ago
The signal status values at that snapshot in time were good but perhaps something intermittent is going on that is beyond your premises. Perhaps there is noise ingress into the line(s) / an upstream channel / return path impairment somewhere. You may want to consider getting a tech out to investigate.
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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XfinityOrlandoM
Official Employee
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2.3K Messages
2 years ago
@S-J70180
Could you please send our team a direct message with your full name and full address? Our team can most definitely take a further look at this issue.
To send a "Direct Message" to Xfinity Support:
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Click the "New message" (pencil and paper) icon
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- As you are typing a drop-down list appears. Select "Xfinity Support" from that list
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