Visitor
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3 Messages
Consistent Lost MDD Timeout and RCS Partial Service Errors
I moved into a new apartment (Denver, CO) on 8/1 and have been dealing with general connectivity issues since returning from a trip on 8/14. As soon as I powered up my modem and router, I noticed that the modem would reset the connection every 15 or so minutes. It was a fairly old modem (SB6141), and not technically supported by Xfinity, so I decided to start with purchasing a new one.
After purchasing and connecting a new modem (SB6910), I'm still experiencing issues, although not as severe. While the modem never appears to lose the connection entirely (doesn't go through a reset cycle), my network speeds are wildly inconsistent (anywhere from 80 Mbps down to 400+) and the modem logs report issues nearly every minute. I finally was able to arrange an onsite tech appointment after multiple support calls but wanted to share my logs and other details in the meantime in case anyone has feedback.
| Startup Procedure | ||
|---|---|---|
| Procedure | Status | Comment |
| Acquire Downstream Channel | Locked | |
| Connectivity State | OK | Operational |
| Boot State | OK | Operational |
| Configuration File | OK | |
| Security | Enabled | BPI+ |
| DOCSIS Network Access Enabled | Allowed | |
| Downstream Bonded Channels | ||||||||
|---|---|---|---|---|---|---|---|---|
| Channel | Lock Status | Modulation | Channel ID | Frequency | Power | SNR | Corrected | Uncorrectables |
| 1 | Locked | 256QAM | 4 | 573.00 MHz | 1.60 dBmV | 43.38 dB | 5 | 0 |
| 2 | Locked | 256QAM | 1 | 555.00 MHz | 1.90 dBmV | 43.38 dB | 11 | 0 |
| 3 | Locked | 256QAM | 2 | 561.00 MHz | 1.90 dBmV | 44.63 dB | 0 | 0 |
| 4 | Locked | 256QAM | 3 | 567.00 MHz | 1.60 dBmV | 43.38 dB | 0 | 0 |
| 5 | Locked | 256QAM | 5 | 579.00 MHz | 1.80 dBmV | 43.38 dB | 8 | 0 |
| 6 | Locked | 256QAM | 6 | 585.00 MHz | 2.00 dBmV | 43.38 dB | 0 | 0 |
| 7 | Locked | 256QAM | 7 | 591.00 MHz | 1.90 dBmV | 43.38 dB | 0 | 0 |
| 8 | Locked | 256QAM | 8 | 597.00 MHz | 1.80 dBmV | 44.63 dB | 0 | 0 |
| 9 | Locked | 256QAM | 9 | 603.00 MHz | 1.80 dBmV | 40.95 dB | 0 | 0 |
| 10 | Locked | 256QAM | 10 | 609.00 MHz | 2.20 dBmV | 43.38 dB | 0 | 0 |
| 11 | Locked | 256QAM | 11 | 615.00 MHz | 2.00 dBmV | 43.38 dB | 0 | 0 |
| 12 | Locked | 256QAM | 12 | 621.00 MHz | 1.80 dBmV | 43.38 dB | 0 | 0 |
| 13 | Locked | 256QAM | 13 | 627.00 MHz | 1.90 dBmV | 43.38 dB | 22 | 0 |
| 14 | Locked | 256QAM | 14 | 633.00 MHz | 2.00 dBmV | 40.95 dB | 0 | 0 |
| 15 | Locked | 256QAM | 15 | 639.00 MHz | 2.30 dBmV | 40.37 dB | 0 | 0 |
| 16 | Locked | 256QAM | 16 | 645.00 MHz | 2.20 dBmV | 40.95 dB | 0 | 0 |
| 17 | Locked | 256QAM | 17 | 651.00 MHz | 2.00 dBmV | 44.63 dB | 0 | 0 |
| 18 | Locked | 256QAM | 18 | 657.00 MHz | 2.30 dBmV | 43.38 dB | 0 | 0 |
| 19 | Locked | 256QAM | 19 | 663.00 MHz | 2.60 dBmV | 43.38 dB | 0 | 0 |
| 20 | Locked | 256QAM | 20 | 669.00 MHz | 2.50 dBmV | 40.95 dB | 0 | 0 |
| 21 | Locked | 256QAM | 21 | 675.00 MHz | 2.30 dBmV | 43.38 dB | 0 | 0 |
| 22 | Locked | 256QAM | 22 | 681.00 MHz | 2.30 dBmV | 40.95 dB | 0 | 0 |
| 23 | Locked | 256QAM | 23 | 687.00 MHz | 2.60 dBmV | 40.95 dB | 0 | 0 |
| 24 | Locked | 256QAM | 24 | 693.00 MHz | 2.70 dBmV | 43.38 dB | 0 | 0 |
| 25 | Locked | 256QAM | 25 | 699.00 MHz | 2.60 dBmV | 42.60 dB | 0 | 0 |
| 26 | Locked | 256QAM | 26 | 705.00 MHz | 2.40 dBmV | 41.90 dB | 0 | 0 |
| 27 | Locked | 256QAM | 27 | 711.00 MHz | 2.70 dBmV | 41.90 dB | 0 | 0 |
| 28 | Locked | 256QAM | 28 | 717.00 MHz | 2.70 dBmV | 41.90 dB | 0 | 0 |
| 29 | Locked | 256QAM | 29 | 723.00 MHz | 2.80 dBmV | 41.90 dB | 0 | 0 |
| 30** | Not Locked | ---- | 30 | 729.00 MHz | ---- | ---- | ---- | ---- |
| 31 | Locked | 256QAM | 31 | 735.00 MHz | 2.50 dBmV | 36.90 dB | 82213 | 138823 |
| 32 | Locked | 256QAM | 32 | 741.00 MHz | 2.70 dBmV | 41.90 dB | 12 | 0 |
**Note: channel 30 fluctuates between not locked and locked but with high amounts of uncorrectables.
| Upstream Bonded Channels | ||||||
|---|---|---|---|---|---|---|
| Channel | Lock Status | US Channel Type | Channel ID | Symbol Rate | Frequency | Power |
| 1 | Locked | ATDMA | 1 | 5120 kSym/s | 16.40 MHz | 40.50 dBmV |
| 2 | Locked | ATDMA | 6 | 2560 kSym/s | 10.40 MHz | 39.96 dBmV |
| 3 | Locked | ATDMA | 5 | 2560 kSym/s | 40.40 MHz | 41.25 dBmV |
| 4 | Locked | ATDMA | 4 | 5120 kSym/s | 35.60 MHz | 41.25 dBmV |
| 5 | Locked | ATDMA | 3 | 5120 kSym/s | 29.20 MHz | 40.75 dBmV |
| 6 | Locked | ATDMA | 2 | 5120 kSym/s | 22.80 MHz | 40.75 dBmV |
Event Log
| Time | Priority | Description |
|---|---|---|
| Tue Aug 17 07:09:55 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"]CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:10:09 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:10:13 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:10:48 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:10:48 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:10:56 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:10:57 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:11:00 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:11:01 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:12:02 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:12:05 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:12:12 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:12:18 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:13:38 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:13:39 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:14:32 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:14:36 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:14:40 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:14:41 2021 | 5 | RCS Partial Service;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
| Tue Aug 17 07:15:16 2021 | 5 | Lost MDD Timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; |
Does anyone have any feedback based on the stats above? I'm happy to provide any additional information that might be helpful.
EG
Expert
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110.2K Messages
4 years ago
Even though the signal stats looked good at that snapshot in time, the error log entries confirm 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 can check the CMTS (Cable Modem Termination System) 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 for those upstream receive signal stats.
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CC_Tony
Retired Employee
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1.4K Messages
4 years ago
@user_17b406
Thank you for taking the time to reach out to our community. We will definitely get to the bottom of this! Please, use the chat icon in the upper-right and compose a new message to "Xfinity Support" with your full name and address, please? We look forward to speaking with you there!
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user_17b406
Visitor
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3 Messages
4 years ago
@XfinityTony thanks! I actually just got a call from Xfinity Advanced support. They reset the modem again, here's what I'm seeing now.
(edited)
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user_17b406
Visitor
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3 Messages
4 years ago
Xfinity sent a technician out on 8/18. They confirmed the issue is due to a faulty cable feeding into my building, but won't be able to get a team out to fix it until September 13th.
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