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user_4g59b9
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Monday, May 5th, 2025 5:35 PM

Consistent T3 time-out in modem logs

Consistent T3 time-out in modem logs

Problem

I believe this line sums up the problem. Found these in modem event log

2025-5-5, 12:24:33 Critical (3)  16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=REDACTED;CMTS-MAC=REDACTED;CM-QOS=1.1;CM-VER=3.0;

Network environment

Feel free to ask questions

Modem NETGEAR CM500-100NAS
Gateway UniFi UCG-Max
Access Point UniFi U7-Pro

Customer Information

DM for information

Question

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Updated 

22 days ago

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0

EG

Expert

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110.7K Messages

26 days ago

Are you actually experiencing any connection problems, or are you just focusing on the error log entries ? 

What do the modem's signal status values look like ?

Please copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.

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user_4g59b9

9 Messages

@EG​  Thanks! I looked into the modem logs after seeing consistent packet loss when streaming and home gaming. We only now installed network gear that allows us clear visibility into our issues. Service connectivity 'succeeds' 5-10 mins after modem reboot. There are no recorded uncorrectable at this moment because I hard reset the modem while troubleshooting.

Startup Procedure

Procedure Status Comment
Acquire Downstream Channel 387000000 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 9 387000000 Hz 8.9 dBmV 41.1 dB 0 0
2 Locked QAM256 10 393000000 Hz 9.1 dBmV 41.3 dB 0 0
3 Locked QAM256 11 399000000 Hz 8.9 dBmV 41.1 dB 0 0
4 Locked QAM256 12 405000000 Hz 8.8 dBmV 40.9 dB 0 0
5 Locked QAM256 13 411000000 Hz 8.5 dBmV 40.6 dB 0 0
6 Locked QAM256 14 417000000 Hz 8.5 dBmV 40.7 dB 0 0
7 Locked QAM256 15 423000000 Hz 8.5 dBmV 40.6 dB 0 0
8 Locked QAM256 16 429000000 Hz 8.6 dBmV 40.7 dB 0 0
9 Locked QAM256 17 435000000 Hz 8.4 dBmV 40.5 dB 0 0
10 Locked QAM256 18 441000000 Hz 8.2 dBmV 40.3 dB 0 0
11 Locked QAM256 19 447000000 Hz 8.1 dBmV 40.3 dB 0 0
12 Locked QAM256 20 453000000 Hz 8.1 dBmV 40.3 dB 0 0
13 Locked QAM256 21 459000000 Hz 8 dBmV 40.2 dB 0 0
14 Locked QAM256 22 465000000 Hz 7.8 dBmV 40.2 dB 0 0
15 Locked QAM256 23 471000000 Hz 7.7 dBmV 40.1 dB 0 0
16 Locked QAM256 24 477000000 Hz 7.7 dBmV 40.1 dB 0

0

Upstream Bonded Channels (Partial Service)

Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 8 5120 Ksym/sec 35600000 Hz 43.3 dBmV
2 Not Locked Unknown 5 0 Ksym/sec 16300000 Hz 0.0 dBmV
3 Not Locked Unknown 6 0 Ksym/sec 22800000 Hz 0.0 dBmV
4 Not Locked Unknown 7 0 Ksym/sec 29200000 Hz 0.0 dBmV

(edited)

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26 days ago

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EG

Expert

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110.7K Messages

26 days ago

The downstream power is a tad on the high side but that may not be a problem. The upstream has only one channel locked in. There should be around three to six. This is typically caused by noise ingress into the line(s) / a connection impairment somewhere. First. Try power cycling the modem one more time. This can sometimes help to pull a new / cleaner set of channels. Please post back with how that goes.

2

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user_4g59b9

9 Messages

Same problem. Since the modem takes minimum 5-10 minutes just to get a lock and provision WAN to its Ethernet output I'm assuming the issue lies beyond CPE.

(edited)

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26 days ago

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user_4g59b9

9 Messages

Please escalate this to a local team.

Washington Township, NJ 07853

(edited)

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26 days ago

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user_4g59b9

9 Messages

25 days ago

@EG any updates to share? It took me 3 tries to download a complete Windows ISO today. Speeds are "ok" considering the current modem hardware, but service quality is questionable at best.

1

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XfinityJamesC

Official Employee

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2.2K Messages

Greetings, @user_4g59b9! Thanks so much for taking a moment out of your busy day to leave a post on our community forum. I'm sorry to hear you're having issues with your connection, but you have definitely come to the right place for assistance.

 

If you could send our team a direct message with your full name, the name listed on the account (if different), and the service address associated with your account, I'd be more than happy to look into this for you.

 

To send a Direct Message, please click on the “Direct Message” icon in the top-right corner of the screen, next to the bell icon, click the "New message" (pencil and paper) icon, then type or select "Xfinity Support". Type your message in the text area near the bottom of the window and press Enter to send your message and initiate a live session.

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

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24 days ago

EG

Expert

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110.7K Messages

23 days ago

@user_4g59b9 @XfinityJamesC 

Please circle back here and post any possible solutions for the issue here in these open public forums so that all readers here may benefit from the exchange / info. This is in keeping with the spirit for which these public help forums were originally intended. Thank you.

2

user_4g59b9

9 Messages

@EG​ The issue was at the pole, outside the home - fixed by technician. Thanks for following up 😎

(edited)

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23 days ago

EG

Expert

 • 

110.7K Messages

@user_4g59b9​ For curiosity, would you please post what the signal values look like now.

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

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22 days ago

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