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sc5250
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Saturday, March 1st, 2025 6:52 PM

Multiple Unicast Maintenance Ranging - No Response received - T3 time-out errors per day, resulting in dropped connections

For the past year, I have been experiencing dropped connections, particularly during VoIP or video conferencing calls.  These drops appear to only happen on the upstream -- my peers cannot hear me, but I am able to hear them perfectly fine.  My cable modem (Motorola MB8600) frequently shows errors like this multiple times a day:

Warning (5)   Dynamic Range Window violation
Warning (5)   RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=n/a;CMTS-MAC=n/a;CM-QOS=1.1;CM-VER=3.1
Warning (5)   RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=n/a;CMTS-MAC=n/a;CM-QOS=1.1;CM-VER=3.1;
Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=n/a;CMTS-MAC=n/a;CM-QOS=1.1;CM-VER=3.1;

I usually experience connection drops around the time the maintenance ranging timeouts occur.  Here's what I've done so far:

- Replaced my Asus Wi-Fi router with a dedicated Ubiquiti access point, switch, and router about 6 month ago in case the Asus wasn't able to handle the traffic (never had an issue with it in the past).

- Had an Xfinity technician (not a contractor) recently come out and check the wiring in the house and replace a few coax connectors. There are no splitters between the cable modem and where the line comes in to the house. The technician could not identify any issues, despite me showing the cable modem logs (they didn't know how to read the information in the logs).

- Tried replacing the MB8600 with an Arris S34 (did not make any difference), swapped back to the MB8600 since it has a built-in spectrum analyzer.

Here are my latest connection details:

Downstream Bonded Channels

   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1 Locked QAM256 5 507.0 2.0 41.3 210 639
   2 Locked QAM256 2 483.0 0.9 40.5 232 731
   3 Locked QAM256 3 489.0 0.7 40.5 212 672
   4 Locked QAM256 4 495.0 0.9 40.6 202 657
   5 Locked QAM256 6 513.0 1.8 41.4 207 609
   6 Locked QAM256 7 519.0 1.5 41.4 204 608
   7 Locked QAM256 8 525.0 1.3 41.2 252 565
   8 Locked QAM256 9 531.0 1.5 41.0 163 505
   9 Locked QAM256 10 537.0 1.3 41.0 181 416
   10 Locked QAM256 11 543.0 1.1 40.9 197 429
   11 Locked QAM256 12 549.0 0.5 40.2 172 442
   12 Locked QAM256 13 555.0 0.5 40.2 198 449
   13 Locked QAM256 14 561.0 0.6 40.6 198 351
   14 Locked QAM256 15 567.0 1.5 40.9 158 374
   15 Locked QAM256 16 573.0 1.3 40.8 137 393
   16 Locked QAM256 17 579.0 1.0 40.7 128 402
   17 Locked QAM256 18 585.0 1.1 40.8 192 316
   18 Locked QAM256 19 591.0 1.5 41.0 175 307
   19 Locked QAM256 20 597.0 2.1 41.1 164 296
   20 Locked QAM256 21 603.0 1.8 41.1 136 340
   21 Locked QAM256 22 609.0 1.5 40.9 157 311
   22 Locked QAM256 23 615.0 1.2 40.9 125 293
   23 Locked QAM256 24 621.0 1.4 40.9 70 290
   24 Locked QAM256 25 627.0 1.6 40.8 129 250
   25 Locked QAM256 26 633.0 1.8 40.9 78 257
   26 Locked QAM256 27 639.0 1.3 40.6 140 254
   27 Locked QAM256 28 645.0 0.9 40.7 57 250
   28 Locked QAM256 29 651.0 0.7 40.2 90 237
   29 Locked QAM256 30 657.0 1.0 40.7 78 257
   30 Locked QAM256 31 663.0 0.7 40.6 92 231
   31 Locked QAM256 32 669.0 0.0 40.3 83 225
   32 Locked OFDM PLC 37 690.0 3.6 41.9 141316353 0

Upstream Bonded Channels

Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Locked SC-QAM 1 5120 35.6 39.0
   2 Locked SC-QAM 2 5120 29.2 39.0
   3 Locked SC-QAM 3 5120 22.8 38.3
   4 Locked SC-QAM 4 5120 16.4 37.8
   5 Locked SC-QAM 5 1280 39.6 39.8

The only things I've been able to identity are:
- The downstream power level spread (dBmV) is > 3, but still less than 4

- The upstream power levels are a bit low, but still in range

What else could be the issue?  I know it's not between the cable modem and my internal networking.

Question

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Updated 

1 month ago

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0

XfinityBillie

Official Employee

 • 

3.2K Messages

1 month ago

 

sc5250 Thank you for taking the time to reach out to us here on our Xfinity Forums. I can definitely understand how frustrating it is to have dropped audio during a meeting! Let's work together to see how we can best assist. Just to clarify, are you using a VPN while on the VoIP or video conferencing calls? I appreciate you detailing out the changes in equipment and that a technician had been out and replaced some connectors. What other circumstances are you experiencing the dropped connections in?

 

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sc5250

2 Messages

Hi @XfinityBillie, there's no VPN being used for any type of traffic.  Since the tech replaced some of the coax connectors, the number of error messages in my cable modem log as definitely increased and I have experience even more dropped connections.  I'm seeing this behavior on streaming video and loading web pages.  The dropped connections are usually no more than 1-2 minutes in length, but enough time to be frustrating.

I'm constant seeing the power levels on the upstream fluctuate between ~36 dBmV and 52 dBmV.  I can correlate seeing these messages, RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW, with the power fluctuations.  I also have more Started Unicast Maintenance Ranging - No Response received - T3 time-out messages as well.

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1 month ago

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XfinityJanelle

Official Employee

 • 

1.5K Messages

We can take a look further into the connection on our side for you and ultimately schedule a technician if you wish. 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":
Click "Sign In" if necessary
• Click the "Direct Message chat" icon
• Click the "New message" (pencil and paper) icon
• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line
• Type your message in the text area near the bottom of the window
• Press Enter to send it

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.
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1 month ago

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XfinityWilliam

Official Employee

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1.1K Messages

1 month ago

Hello @sc5250. I am glad we were able to get a technician out there and get everything fixed for you! Thanks so much for being a wonderful Xfinity customer. Have a great rest of your week!

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