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How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

Frequent Visitor

How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

I'm a brand new Comcast/Xfinity user and I got my internet (300Mbps) installed 10 days ago. Since the beginning I've noticed some intermitent and random packet loss (1% - 2%). I changed the modem 3 times and all 4 modems showed the same CM Errors with Uncorrectable Codewords in all columns.

I connected the modem to the grey box, outside of my house, and I noticed the errors are also happening when I plug it over there, so it doesn't seem to be related to my internal cabling.

I've opened a dozen of tickets with Comcast and a techinician came to my house, but he didn't have the tools nor the knowledge to do anything. He simply left, leving all my wires and cables exposed to the weather, and with the modem connected to the grey box.

I think it is an easy thing over the "last mile" but it seems nobody from Comcast is really trying to help me get it fixed.

Is there anybody from Comcast here that could help me with this issue?

Frequent Visitor

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

Here you are the data from my XB6 modem:

 

Downstream

                                                                 
Index

9

6

7

8

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

 
Lock Status

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Locked

Frequency

543 MHz

525 MHz

531 MHz

537 MHz

555 MHz

561 MHz

567 MHz

573 MHz

579 MHz

585 MHz

591 MHz

597 MHz

603 MHz

609 MHz

615 MHz

621 MHz

627 MHz

633 MHz

639 MHz

645 MHz

651 MHz

657 MHz

663 MHz

669 MHz

675 MHz

681 MHz

687 MHz

762 MHz

693 MHz

699 MHz

705 MHz

711 MHz

659600000

SNR

40.4 dB

40.0 dB

39.7 dB

40.7 dB

39.6 dB

40.1 dB

40.3 dB

38.1 dB

41.2 dB

40.8 dB

40.6 dB

40.7 dB

41.0 dB

40.4 dB

40.7 dB

40.6 dB

40.0 dB

40.5 dB

40.3 dB

38.4 dB

40.6 dB

39.8 dB

39.3 dB

39.3 dB

40.5 dB

39.6 dB

39.9 dB

39.1 dB

40.4 dB

39.5 dB

38.9 dB

38.5 dB

NA

Power Level

-1.2 dBmV

-2.2 dBmV

-2.0 dBmV

0.2 dBmV

-2.9 dBmV

-2.8 dBmV

-2.5 dBmV

-1.0 dBmV

0.4 dBmV

0.1 dBmV

-2.1 dBmV

-1.7 dBmV

0.9 dBmV

0.2 dBmV

0.4 dBmV

0.4 dBmV

-2.0 dBmV

-2.0 dBmV

-1.8 dBmV

-1.8 dBmV

-1.8 dBmV

-3.4 dBmV

-4.1 dBmV

-2.6 dBmV

-1.7 dBmV

-2.0 dBmV

-2.8 dBmV

-5.2 dBmV

-3.2 dBmV

-4.6 dBmV

-5.3 dBmV

-4.5 dBmV

NA

Modulation

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

256 QAM

OFDM

256 QAM

256 QAM

256 QAM

256 QAM

OFDM

                                                                   

Upstream

                                                                 
Index

1

2

3

4

                                                         
Lock Status

Locked

Locked

Locked

Locked

                                                         
Frequency

35 MHz

29 MHz

23 MHz

16 MHz

                                                         
Symbol Rate

5120

5120

5120

5120

                                                         
Power Level

43.3 dBmV

43.5 dBmV

43.8 dBmV

42.5 dBmV

                                                         
Modulation

QAM

QAM

QAM

QAM

                                                         
Channel Type

ATDMA

ATDMA

ATDMA

ATDMA

                                                         
                                                                   

CM Error Codewords

                                                                 
Index

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

 
Unerrored Codewords

129741384

129677779

129683737

129688132

129690008

129693662

129698301

129703047

129709181

129713324

129718688

129722873

129725898

129730171

129734808

129738059

129741000

129744988

129745882

129749890

129752246

129754279

129754522

129757195

129758848

129752495

129749240

8564857

129742276

129741795

129741245

129741384

 
Correctable Codewords

41023

9617

9066

9668

10891

11734

11823

12148

11845

12471

12662

13235

14057

14441

14776

14986

16891

17598

18918

19678

20857

22613

25496

26216

27899

28801

31647

1071287

33712

36697

39313

41023

 
Uncorrectable Codewords

32337

5493

6312

6447

7501

7778

8188

8278

8358

8656

9234

9098

9566

10217

10441

11009

11824

12640

13851

14824

15697

17110

19098

20230

21858

22928

25251

0

26109

28413

31349

32337

 
Expert

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

What do the modem's signal stats look like ? Try getting them here http://192.168.100.1 or here http://10.0.0.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

What is the exact make and model number of the modem ?

Is this a WiFi connection ?



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Frequent Visitor

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

 


@EG wrote:

What do the modem's signal stats look like ? Try getting them here http://192.168.100.1 or here http://10.0.0.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

What is the exact make and model number of the modem ?

Is this a WiFi connection ?


Hi @EG , I included the power levels and SNR info in my first reply. Here you are the details of my modem:

 

HW Version:2.2

Vendor:Technicolor

BOOT Version:S1TC-3.49.18.14

Core Version:1.0

Model:CGM4140COM

Product Type:XB6

Flash Part:8192 MB

Download Versionrod_18.1_d31 & Prod_18.1

 

I'm getting those errors in both cases, even if I disable wifi and only work using the ethernet cable.

 

Thanks,

Luiz

Expert

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

Sorry, my bad. The stats are o/k. See if you can get the RF error log entries and post them too please.



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Frequent Visitor

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

I can only see System, Event or Firewall logs. This is the System Logs since the last reboot:

 

System Logs    
All logs for Today    
GUI: User:admin login 11/19/2019 14:33 Notice
GUI: User:admin logout 11/19/2019 14:28 Notice
[IGD][10025]: Delete Port mapping (null):36395 11/19/2019 14:16 Notice
IGD[10025]: igd.info IGD_pii_del_portmapping_entry: remote-host (null), ext_port 36395, protocol UDP 11/19/2019 14:16 Notice
[IGD][10025]: Add Port mapping :36395 to 10.0.0.163:36395 11/19/2019 14:15 Notice
IGD[10025]: igd.info IGD_pii_add_portmapping_entry: desc WhatsApp (1574190899) (), ext_port 36395, int_port 36395 11/19/2019 14:15 Notice
GUI: User:admin login 11/19/2019 14:11 Notice
GUI: User:admin logout 11/19/2019 13:56 Notice
[IGD][10025]: Add Port mapping :49525 to 10.0.0.236:49525 11/19/2019 13:45 Notice
IGD[10025]: igd.info IGD_pii_add_portmapping_entry: desc Teredo 10.0.0.236:49525->49525 UDP, ext_port 49525, int_port 49525 11/19/2019 13:45 Notice
GUI: User:admin login 11/19/2019 13:39 Notice
GUI: User:admin logout 11/19/2019 13:36 Notice
GUI: User:admin login 11/19/2019 12:53 Notice
Expert

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

The router component logs are not helpful, sorry. Yep, we've seen many posts here recently indicating that they have now blocked the end user from accessing the error logs in the Comcast supplied gateway devices. A BIG mistake in my opinion......



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Expert

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?


@LuizAlexandre wrote:

I'm getting those errors in both cases, even if I disable wifi and only work using the ethernet cable.


O/k but are you getting packet loss via hardline ethernet ?



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Frequent Visitor

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

Since that's intermitent and I changed the modem 3 times already,  I'll work hardwired tomorrow to validate that's still happening.

I'll post an update tomorrow.

Frequent Visitor

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

I've tested internet connectivity this morning and I did not miss any "ping" packets while connected via wireless or wired, but my CM errors are still piling up:

 

CM Error Codewords

                                                               
Index

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

Unerrored Codewords

4020924988

4023106335

4023030075

4022990056

4022826309

4022799098

4022785301

4022794968

4022790033

4022773107

4022727686

4022681407

4022655799

4022610742

4022553746

4022499611

4022390197

4022306239

4022216140

4022122979

4022022301

4021905841

4021783980

4021728565

4021613416

4021538057

4021402659

601993134

4021302061

4021151652

4021004116

4020924988

Correctable Codewords

1397702

553294

580428

593651

657425

667036

676404

671482

672856

679465

702511

723220

730743

749328

771900

787584

834981

868115

898634

934160

973910

1026920

1079709

1086947

1139066

1153714

1208323

36773924

1247911

1317106

1376695

1397702

Uncorrectable Codewords

2304959

850453

904351

936423

1039345

1061897

1072269

1072666

1088807

1102634

1131541

1161924

1183051

1216226

1255418

1296960

1366097

1421331

1486117

1547833

1614216

1681894

1756046

1808898

1875936

1934385

2015871

57

2066356

2153594

2247925

2304959

Frequent Visitor

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

Hi @EG , is there anything I can/should do to eliminate the CM Errors?

Expert

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

Well there will always be a certain amount of errors accumulating, it's how rapidly that there are (or are not) building up that matters. And depending on the total amount of uptime of the modem from the last re-boot / reset operation, If you compare the ratio of uncorrectable codewords to the un-errored codewords, there really may not be all that many considering. The bottom line is if you are actually having any noticeable connection / speed / performance problems.



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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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Frequent Visitor

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

Got it .... I'll keep an eye on it and get back here if I see anything impacting my connectivity or performance.

Thanks !!!

Luiz

Expert

Re: How can I get rid of continuous CM Errors - Uncorrectable Codewords ?

Re-boot / power cycle the modem to start from scratch in order to be able to judge how fast that they are accumulating.



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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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