T

Visitor

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4 Messages

Fri, Sep 10, 2021 6:50 PM

High number of uncorrectables and internet connectivity issues

I am having connectivity drops multiple times a day. It started about 2 years ago and would only happen occasionally but has steadily gotten worse. It currently happens 15+ times a day and has become nearly unusable. Speed test sites report no speed issues and when I am on the Xfinity connection test page, I can reload the page when the uncorrectables are stacking up and it says my connection is fine even though the page takes 30 seconds to load (seems kinda sketchy)

I tested the coax from the modem to the box outside and there are no shorts and only 1 splitter. The center cable is not open end to end or shorted to the shielding jacket, and the case is the same with the shielding jacket. The shielding jacket is grounded to the electrical meter outside. The coax was brand new when installed in 2017 and does not have any bends that are more than a moderately wide turn to go through the floor. The ethernet cable from the modem to the router is a Monster brand (140272-00) cat5E 3ft cable (bought brand new yesterday). I also replaced the splitter with a double male coax connector. I am very confident the cabling inside the house is good and not the issue. I have not tried a different modem but I have removed the router from the equation with no change. I do not believe there is any issue with the modem. Both the modem and the router were off and unplugged for well over an hour yesterday and I've rebooted them both within the past ~30 minutes.

200mbps +blast

Hardware:

Zoom 5370 Cable Modem - 2yrs old

TP-Link Archer C9 wireless router - 2yrs old

Connection info from the modem - restarted roughly 30 minutes ago ~1pm CST

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 447000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK d11_m_5370_speedtierextreme2_c01.cm
Security Enabled BPI+


Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 42 447000000 Hz -0.7 dBmV 40.4 dB 115 347
2 Locked QAM256 43 453000000 Hz -0.6 dBmV 40.5 dB 142 309
3 Locked QAM256 44 459000000 Hz -0.7 dBmV 40.5 dB 99 274
4 Locked QAM256 45 465000000 Hz -1.0 dBmV 40.3 dB 179 255
5 Locked QAM256 38 471000000 Hz -1.1 dBmV 40.3 dB 139 251
6 Locked QAM256 39 477000000 Hz -1.0 dBmV 40.2 dB 92 210
7 Locked QAM256 40 483000000 Hz -1.2 dBmV 40.2 dB 51 247
8 Locked QAM256 41 489000000 Hz -1.4 dBmV 40.1 dB 118 407
9 Locked QAM256 33 495000000 Hz -1.3 dBmV 40.1 dB 107 308
10 Locked QAM256 34 507000000 Hz -1.1 dBmV 36.5 dB 117 320
11 Locked QAM256 35 513000000 Hz -0.7 dBmV 40.2 dB 75 208
12 Locked QAM256 36 519000000 Hz -0.6 dBmV 40.2 dB 127 342
13 Locked QAM256 1 525000000 Hz -0.4 dBmV 40.2 dB 80 279
14 Locked QAM256 2 531000000 Hz -0.5 dBmV 40.2 dB 119 260
15 Locked QAM256 3 537000000 Hz -0.3 dBmV 40.2 dB 122 415
16 Locked QAM256 4 543000000 Hz -0.4 dBmV 40.2 dB 95 236

Total Correctables Total Uncorrectables
1777 4668


Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 4 5120 Ksym/sec 16400000 Hz 46.2 dBmV
2 Locked ATDMA 5 2560 Ksym/sec 40400000 Hz 42.8 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 22800000 Hz 44.7 dBmV
4 Locked ATDMA 2 5120 Ksym/sec 29200000 Hz 45.5 dBmV

CM IP Address Duration Expires
2001:558:4040:8c:fe4a:e9ff:fe32:5b99/128 D: 04 H: 18 M: 54 S: 41 Wed Sep 15 07:38:57 2021

The downstream channel power is usually near 0 +/- .3dBmV.

SNR stays consistent near 40dB.

The upstream channel power is usually 39-40dBmV

Event log for the past ~30 minutes:

Fri Sep 10 12:39:52 2021   Critical (3)  Started Unicast Maintenance Ranging - No Response received - ...  

Fri Sep 10 12:23:05 2021   Critical (3)  16 consecutive T3 timeouts while trying to range on upstream ...  

Fri Sep 10 12:23:05 2021   Critical (3)  Unicast Maintenance Ranging attempted - No response - Retries...  

Fri Sep 10 12:23:05 2021   Critical (3)  Started Unicast Maintenance Ranging - No Response received - ...  

Fri Sep 10 12:23:01 2021   Critical (3)  16 consecutive T3 timeouts while trying to range on upstream ...  

Fri Sep 10 12:23:01 2021   Critical (3)  Unicast Maintenance Ranging attempted - No response - Retries...  

Fri Sep 10 12:23:01 2021   Critical (3)  Started Unicast Maintenance Ranging - No Response received - ... 

Let me know if anything else is needed. 

This post was escalated on September 15, 2021 by EG

Responses

EG

Expert

 • 

89.1K Messages

11 d 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) /  an upstream channel-return path impairment 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 !

Visitor

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4 Messages

@EG

Thank you so much! 

EG

Expert

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89.1K Messages

@TealHouse

Quite welcome ! 🙂 Please post back with how things turn out. 

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

Visitor

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4 Messages

6 d ago

Quick update: 

No contact from xfinity. Updated numbers-

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 447000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK d11_m_5370_speedtierextreme2_c01.cm
Security Enabled BPI+


Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 42 447000000 Hz 0.4 dBmV 40.6 dB 4066 5375
2 Locked QAM256 43 453000000 Hz 0.4 dBmV 40.7 dB 3922 4702
3 Locked QAM256 44 459000000 Hz 0.6 dBmV 40.8 dB 3646 4792
4 Locked QAM256 45 465000000 Hz 0.5 dBmV 40.6 dB 3696 4617
5 Locked QAM256 38 471000000 Hz 0.3 dBmV 40.6 dB 3535 3949
6 Locked QAM256 39 477000000 Hz 0.5 dBmV 40.5 dB 3470 4725
7 Locked QAM256 40 483000000 Hz 0.3 dBmV 40.4 dB 3392 4133
8 Locked QAM256 41 489000000 Hz 0.1 dBmV 40.3 dB 3271 4359
9 Locked QAM256 33 495000000 Hz 0.2 dBmV 40.3 dB 3173 4149
10 Locked QAM256 34 507000000 Hz 0.3 dBmV 37.3 dB 3102 4488
11 Locked QAM256 35 513000000 Hz 0.7 dBmV 40.4 dB 2828 3928
12 Locked QAM256 36 519000000 Hz 0.8 dBmV 40.3 dB 2721 4083
13 Locked QAM256 1 525000000 Hz 0.9 dBmV 40.3 dB 2652 4612
14 Locked QAM256 2 531000000 Hz 0.8 dBmV 40.4 dB 2531 3928
15 Locked QAM256 3 537000000 Hz 1.0 dBmV 40.4 dB 2493 3818
16 Locked QAM256 4 543000000 Hz 1.0 dBmV 40.5 dB 2332 3662

Total Correctables Total Uncorrectables
50830 69320


Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 4 5120 Ksym/sec 16400000 Hz 43.7 dBmV
2 Locked ATDMA 5 2560 Ksym/sec 40400000 Hz 40.0 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 22800000 Hz 42.1 dBmV
4 Locked ATDMA 2 5120 Ksym/sec 29200000 Hz 43.0 dBmV

CM IP Address Duration Expires
2001:558:4040:8c:fe4a:e9ff:fe32:5b99/128 D: 07 H: 00 M: 00 S: 00 Tue Sep 21 20:45:12 2021
Downstream Frequency Select (in KHz)

Current System Time: Tue Sep 14 20:45:12 2021

Tue Sep 14 20:38:00 2021   Critical (3)  Started Unicast Maintenance Ranging - No Response received - ...  
Tue Sep 14 07:15:55 2021   Warning (5)  Dynamic Range Window violation  
Tue Sep 14 07:14:02 2021   Critical (3)  Started Unicast Maintenance Ranging - No Response received - ...  
Sat Sep 11 12:26:36 2021   Critical (3)  16 consecutive T3 timeouts while trying to range on upstream ...  Sat Sep 11 12:26:36 2021   Critical (3)  Unicast Maintenance Ranging attempted - No response - Retries...  Sat Sep 11 12:26:36 2021   Critical (3)  Started Unicast Maintenance Ranging - No Response received - ...  Sat Sep 11 12:26:35 2021   Critical (3)  16 consecutive T3 timeouts while trying to range on upstream ...  Sat Sep 11 12:26:35 2021   Critical (3)  Unicast Maintenance Ranging attempted - No response - Retries...  Sat Sep 11 12:26:35 2021   Critical (3)  Started Unicast Maintenance Ranging - No Response received - ...  Fri Sep 10 12:23:05 2021   Critical (3)  16 consecutive T3 timeouts while trying to range on upstream ...  Fri Sep 10 12:23:05 2021   Critical (3)  Unicast Maintenance Ranging attempted - No response - Retries...  Fri Sep 10 12:23:05 2021   Critical (3)  Started Unicast Maintenance Ranging - No Response received - ...  Fri Sep 10 12:23:01 2021   Critical (3)  16 consecutive T3 timeouts while trying to range on upstream ...  Fri Sep 10 12:23:01 2021   Critical (3)  Unicast Maintenance Ranging attempted - No response - Retries...  Fri Sep 10 12:23:01 2021   Critical (3)  Started Unicast Maintenance Ranging - No Response received - ... 

Official Employee

 • 

2.9K Messages

Hello, @TealHouse

I'm so sorry we didn't see your escalated post earlier, I'm not sure how it slipped past us. I would love to take a closer look into your signal health and history so we can get this figured out. Please send us a Direct Message with your first and last name as well as your service address so we can assist. 

 

To send a Direct Message, please click on the chat icon on the top right of this page, next to the bell. Make sure to send the message to our singular handle "Xfinity Support" and we will get back to you ASAP.

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

Visitor

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4 Messages

@XfinityTambrey 

Done, thank you!

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