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Visitor

 • 

5 Messages

Tue, Aug 3, 2021 6:54 PM

Sudden speed drop after xfinity outage in my area

I recently upgraded my internet speed to 1.2Gb and added a self purchased modem Netgear CM2050v.  I was able to get speeds in the 950Mbs range which I was happy with given my connection to the modem is currently only 1gb not the 2.5gb.   My speeds when connected directly to the modem are now frequently in the 500-600Mbs range and I am wondering if I could get some assistance in looking at the logs.  I have done resets/unplugs of the modem and connected directly to It with nothing really changing.  I have done speed tests straight to xfinity.speedtest.com as well. Not sure if it maters but the clock seems to be off by 1hr I assume DST.

I do see the following message in the log upon rebooting:

Mon Aug 02 21:28:17 2021 (Warning (5)) DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
Mon Aug 02 21:28:15 2021 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;

Cable Connection
Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 579000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 25 579000000 Hz 2.0 dBmV 39.2 dB 0 0
2 Locked QAM256 1 423000000 Hz 5.3 dBmV 40.1 dB 0 0
3 Locked QAM256 2 429000000 Hz 5.5 dBmV 40.1 dB 0 0
4 Locked QAM256 3 435000000 Hz 5.6 dBmV 40.1 dB 0 0
5 Locked QAM256 4 441000000 Hz 5.5 dBmV 40.1 dB 0 0
6 Locked QAM256 5 447000000 Hz 5.5 dBmV 40.3 dB 0 0
7 Locked QAM256 6 453000000 Hz 5.5 dBmV 40.5 dB 0 0
8 Locked QAM256 7 459000000 Hz 5.2 dBmV 40.4 dB 0 0
9 Locked QAM256 8 465000000 Hz 4.9 dBmV 40.3 dB 0 0
10 Locked QAM256 9 471000000 Hz 4.6 dBmV 40.2 dB 0 0
11 Locked QAM256 10 477000000 Hz 4.4 dBmV 40.2 dB 0 0
12 Locked QAM256 11 483000000 Hz 4.3 dBmV 40.3 dB 0 0
13 Locked QAM256 12 489000000 Hz 4.2 dBmV 40.4 dB 0 0
14 Locked QAM256 13 495000000 Hz 3.8 dBmV 40.2 dB 0 0
15 Locked QAM256 14 507000000 Hz 3.6 dBmV 40.2 dB 0 0
16 Locked QAM256 15 513000000 Hz 3.3 dBmV 40.0 dB 0 0
17 Locked QAM256 16 519000000 Hz 3.2 dBmV 39.9 dB 0 0
18 Locked QAM256 17 525000000 Hz 3.0 dBmV 39.9 dB 0 0
19 Locked QAM256 18 531000000 Hz 2.6 dBmV 39.7 dB 0 0
20 Locked QAM256 19 543000000 Hz 2.1 dBmV 39.6 dB 0 0
21 Locked QAM256 20 549000000 Hz 1.9 dBmV 39.5 dB 0 0
22 Locked QAM256 21 555000000 Hz 1.8 dBmV 39.2 dB 0 0
23 Locked QAM256 22 561000000 Hz 1.8 dBmV 39.2 dB 0 0
24 Locked QAM256 23 567000000 Hz 1.8 dBmV 39.1 dB 0 0
25 Locked QAM256 24 573000000 Hz 2.0 dBmV 39.2 dB 0 0
26 Locked QAM256 26 585000000 Hz 2.3 dBmV 39.3 dB 0 0
27 Locked QAM256 27 591000000 Hz 2.4 dBmV 39.2 dB 0 0
28 Locked QAM256 28 597000000 Hz 2.5 dBmV 39.2 dB 0 0
29 Locked QAM256 29 603000000 Hz 2.7 dBmV 39.1 dB 1 0
30 Locked QAM256 30 609000000 Hz 2.7 dBmV 39.0 dB 1 0
31 Locked QAM256 31 615000000 Hz 2.6 dBmV 39.0 dB 193 0
32 Locked QAM256 32 621000000 Hz 2.7 dBmV 39.0 dB 1105097 32161
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 16400000 Hz 37.3 dBmV
2 Locked ATDMA 2 5120 22800000 Hz 37.8 dBmV
3 Locked ATDMA 3 5120 29200000 Hz 38.8 dBmV
4 Locked ATDMA 4 5120 35600000 Hz 39.3 dBmV
5 Locked ATDMA 5 2560 40400000 Hz 39.8 dBmV
6 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
 
Downstream OFDM Channels
Channel Lock Status Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1 Locked 0 ,1 159 722000000 Hz -0.1 dBmV 37.6 dB 1246 ~ 2849 3145641141 518182283 2590
2 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0
 
Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV
 
Current System Time:Tue Aug 03 20:34:17 2021
System Up Time:23:19:07
This post was escalated on August 5, 2021 by EG

Responses

Visitor

 • 

5 Messages

2 m ago

Is there something more I need to include to get help with this? I have a new splitter coming for the outside of the house to replace a much older 3:1 that is currently used. 

J.

EG

Expert

 • 

89.2K Messages

2 m ago

The signal status figures are o/k.  Please post the error log entries in their entirety but redact the CM and the CMTS MAC addresses for your privacy.

Visitor

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5 Messages

2 m ago

Thank you, I have been resetting/rebooting a lot but here is my log currently.

Time

Priority

Description

Thu Aug 05 06:44:33 2021

(Notice (6))

CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 1.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Thu Aug 05 06:44:05 2021

(Notice (6))

CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 1.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:31:16 2021

(Notice (6))

CM-STATUS message sent. Event Type Code: 3; Chan ID: N/A; DSID: -; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:31:10 2021

(Warning (5))

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:31:10 2021

(Critical (3))

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:19:12 2021

(Notice (6))

CM-STATUS message sent. Event Type Code: 5; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:19:05 2021

(Warning (5))

Dynamic Range Window violation

Wed Aug 04 21:19:05 2021

(Warning (5))

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:19:04 2021

(Warning (5))

REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:18:58 2021

(Notice (6))

DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:18:53 2021

(Notice (6))

TLV-11 - unrecognized OID;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

(Notice (6))

Honoring MDD; IP provisioning mode = IPv6

Time Not Established

(Critical (3))

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=Redacted-CM-MAC;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:09:04 2021

(Notice (6))

CM-STATUS message sent. Event Type Code: 5; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:08:54 2021

(Warning (5))

Dynamic Range Window violation

Wed Aug 04 21:08:54 2021

(Warning (5))

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:08:53 2021

(Warning (5))

REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:08:48 2021

(Notice (6))

DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:08:43 2021

(Notice (6))

TLV-11 - unrecognized OID;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

(Notice (6))

Honoring MDD; IP provisioning mode = IPv6

Time Not Established

(Critical (3))

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=Redacted-CM-MAC;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:03:34 2021

(Notice (6))

CM-STATUS message sent. Event Type Code: 5; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:03:23 2021

(Warning (5))

REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:03:17 2021

(Notice (6))

DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 21:03:12 2021

(Notice (6))

TLV-11 - unrecognized OID;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

(Notice (6))

Honoring MDD; IP provisioning mode = IPv6

Time Not Established

(Critical (3))

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=Redacted-CM-MAC;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 20:56:41 2021

(Notice (6))

CM-STATUS message sent. Event Type Code: 5; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 20:56:34 2021

(Warning (5))

Dynamic Range Window violation

Wed Aug 04 20:56:34 2021

(Warning (5))

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 20:56:34 2021

(Warning (5))

Dynamic Range Window violation

Wed Aug 04 20:56:34 2021

(Warning (5))

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 20:56:34 2021

(Warning (5))

Dynamic Range Window violation

Wed Aug 04 20:56:34 2021

(Warning (5))

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 20:56:34 2021

(Warning (5))

Dynamic Range Window violation

Wed Aug 04 20:56:34 2021

(Warning (5))

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 20:56:33 2021

(Warning (5))

REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 20:56:28 2021

(Notice (6))

DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Wed Aug 04 20:56:23 2021

(Notice (6))

TLV-11 - unrecognized OID;CM-MAC=Redacted-CM-MAC;CMTS-MAC=Redacted-CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

(Notice (6))

Honoring MDD; IP provisioning mode = IPv6

Visitor

 • 

5 Messages

2 m ago

My connection was rebooted 12 hours ago but I have these upstream channels with a few uncorrectable errors:

22 Locked QAM256 34 633000000 Hz 2.5 dBmV 39.0 dB 12 22
23 Locked QAM256 35 639000000 Hz 2.0 dBmV 38.7 dB 11 25

and What is typical for Downstream OFDM, there always seems to be some uncorrectable codewords but I don't know what "a lot" looks like.

Downstream OFDM Channels
Channel Lock Status Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1 Locked 0 ,1 159 722000000 Hz -0.1 dBmV 37.8 dB 1246 ~ 2849 1571032394 128287991 6285
2 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0

Official Employee

 • 

202 Messages

Hello, @user_3472c1. I'd like to thank you for making us aware your internet speeds aren't exactly where they're suppose. I appreciate you taking the time to troubleshoot on your own to find a solution to this problem. I would be more than happy to review your logs and help locate the root cause to this inconvenience you're experiencing.

 

In order to get started can you please send me a private message to Xfinity Support with your full name and full address by clicking the chat icon in the top right?

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
EG

Expert

 • 

89.2K Messages

2 m 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

 • 

5 Messages

2 m ago

Thank you I really appreciate it.  My new splitter should come tomorrow and I'll install it right away just as a cya but honestly I was pretty consistent 940Mbs there for a week or two and then it dropped to half that suddenly around the same time my area had an outage.  

Thanks for looking at this EG.. I'll update this if I hear from them.

Official Employee

 • 

202 Messages

We look forward to hearing from @user_3472c1. Please send me a private message to Xfinity Support with your full name and full address by clicking the chat icon in the top right.

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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