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DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

Frequent Visitor

DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

Back in May, I upgraded my service from the 150mbps tier to the 1Gbps tier. 

 

I have since had four technicians come out and replace everything from the tap to the modem. I have tried different modem OEMs that are both on the approved list of modems. 

 

The issue seems to be related to how hot it is outside. When its cool (~60F) things are working fine. But when it gets above 65F I'm getting dropouts. The hotter, the worse it is. 

 

The last tech that I had out said that he did see some issues with the uncorrectables and MER/SNR, but wasn't sure if it was enough to be able to open a maintenance ticket on it. 

 

 

Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency

<tabindex=-1>Startup Procedure</tabindex=-1>
Procedure Status Comment
Acquire Downstream Channel 489000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enable BPI+
IP Provisioning Mode Honor MDD IPv6 only

<tabindex=-1>Downstream Bonded Channels</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power SNR / MER Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked QAM256 18 489000000 Hz 3.0 dBmV 38.5 dB 86239976 3269479 6590020
2 Locked QAM256 1 531000000 Hz 2.1 dBmV 41.8 dB 82688574 3875553 8492391
3 Locked QAM256 2 537000000 Hz 2.3 dBmV 31.4 dB 82324125 3954696 8781020
4 Locked QAM256 3 543000000 Hz 2.0 dBmV 30.6 dB 81760196 4096097 9207168
5 Locked QAM256 4 549000000 Hz 2.2 dBmV 42.2 dB 81394901 4175204 9496612
6 Locked QAM256 5 555000000 Hz 1.8 dBmV 41.7 dB 80886050 4304457 9874323
7 Locked QAM256 6 561000000 Hz 1.7 dBmV 28.9 dB 80586435 4375854 10106615
8 Locked QAM256 7 567000000 Hz 1.5 dBmV 41.7 dB 80231406 4463125 10378720
9 Locked QAM256 8 573000000 Hz 1.6 dBmV 37.8 dB 79998531 4522447 10562305
10 Locked QAM256 9 579000000 Hz 1.8 dBmV 30.5 dB 79790327 4591052 10706041
11 Locked QAM256 10 585000000 Hz 1.5 dBmV 35.5 dB 79391013 4658459 11041416
12 Locked QAM256 11 591000000 Hz 1.7 dBmV 39.6 dB 78998998 4752141 11343403
13 Locked QAM256 12 597000000 Hz 2.0 dBmV 39.6 dB 78717740 4815455 11565511
14 Locked QAM256 13 603000000 Hz 2.2 dBmV 34.2 dB 78314462 4901783 11886491
15 Locked QAM256 14 609000000 Hz 1.9 dBmV 33.3 dB 78005986 4979002 12121918
16 Locked QAM256 15 615000000 Hz 1.8 dBmV 41.0 dB 77516294 5095241 12498667
17 Locked QAM256 16 621000000 Hz 2.0 dBmV 40.9 dB 77106728 5187487 12839254
18 Locked QAM256 17 483000000 Hz 3.0 dBmV 42.9 dB 85688211 3177712 6268386
19 Locked QAM256 19 495000000 Hz 2.8 dBmV 40.3 dB 85007021 3339347 6792807
20 Locked QAM256 20 501000000 Hz 2.8 dBmV 42.1 dB 84790908 3397760 6954998
21 Locked QAM256 21 507000000 Hz 2.9 dBmV 31.0 dB 84503215 3458650 7185280
22 Locked QAM256 22 513000000 Hz 2.9 dBmV 33.9 dB 84202572 3535905 7413342
23 Locked QAM256 23 519000000 Hz 2.9 dBmV 42.3 dB 83628774 3670096 7857010
24 Locked QAM256 24 525000000 Hz 2.5 dBmV 33.9 dB 83299447 3745317 8115698
25 Locked QAM256 25 627000000 Hz 2.4 dBmV 37.5 dB 76995720 5220433 12947912
26 Locked QAM256 26 633000000 Hz 2.3 dBmV 40.9 dB 76729111 5274285 13164263
27 Locked QAM256 27 639000000 Hz 2.1 dBmV 41.4 dB 76233846 5399758 13538133
28 Locked QAM256 33 459000000 Hz 3.5 dBmV 39.7 dB 87286276 2814759 5074227
29 Locked QAM256 34 465000000 Hz 3.7 dBmV 42.3 dB 86855148 2919498 5404451
30 Locked QAM256 35 471000000 Hz 3.3 dBmV 41.4 dB 86620120 2976801 5584133
31 Locked QAM256 36 477000000 Hz 3.2 dBmV 41.5 dB 86202054 3079273 5902131
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0

<tabindex=-1>Upstream Bonded Channels</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power
1 Locked ATDMA 5 35800000 Hz 46.5 dBmV
2 Locked ATDMA 6 29400000 Hz 46.3 dBmV
3 Locked ATDMA 7 23000000 Hz 45.8 dBmV
4 Locked ATDMA 8 16600000 Hz 44.8 dBmV
5 Not Locked Unknown 0 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Hz 0.0 dBmV

<tabindex=-1>Downstream OFDM Channels</tabindex=-1>
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier Number Range Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked 0, 1, 255 37 690000000 Hz 2.1 dBmV 40.0 dB 1228 ~ 2867 8792922676 8660380539 0
2 Not Locked 0, 255 0 0 Hz 3.1 dBmV 0.0 dB 0 ~ 4095 0 0 0

<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked Unknown 0 0 Hz 0 dBmV
2 Not Locked Unknown 0 0 Hz 0 dBmV

 

Can share more info on request. @ComcastAmir my husband requested that I tag you here. 

Expert

Re: DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

The SNR is too low / out of spec on some of the downstream channels. Seems that there is some noise ingress leaking into the line(s) somewhere. I would get the techs involved again to investigate / correct this. The problem may lie somewhere beyond your premises but it is their SOP to start in your home. The premises facing techs are supposed to refer an issue to the line / maintenance techs if they deem that the problem is not in the home. Good luck with it. 



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Frequent Visitor

Re: DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

Thanks, @EG! This was taken during a time when it's working okay. 

 

I have seen it dip down into the mid-20s when it starts to heat up. Hopefully, we can get some resolution soon!

Expert

Re: DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

Yep. Heat exacerbates the problem / impairment because it adds resistance to the lines.



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? Mark the post as Best Answer!
Frequent Visitor

Re: DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

More logging:

Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency

<tabindex=-1>Startup Procedure</tabindex=-1>
Procedure Status Comment
Acquire Downstream Channel 489000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enable BPI+
IP Provisioning Mode Honor MDD IPv6 only

<tabindex=-1>Downstream Bonded Channels</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power SNR / MER Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked QAM256 18 489000000 Hz 3.1 dBmV 39.8 dB 891508255 7905001 12933562
2 Locked QAM256 1 531000000 Hz 2.1 dBmV 34.4 dB 883174398 9815889 18336639
3 Locked QAM256 2 537000000 Hz 2.1 dBmV 41.7 dB 882087831 10083217 19159069
4 Locked QAM256 3 543000000 Hz 1.8 dBmV 41.7 dB 880421325 10501410 20410773
5 Locked QAM256 4 549000000 Hz 1.8 dBmV 30.1 dB 879316784 10756617 21263513
6 Locked QAM256 5 555000000 Hz 1.8 dBmV 37.5 dB 877812162 11139842 22383029
7 Locked QAM256 6 561000000 Hz 1.6 dBmV 35.3 dB 876941337 11350793 23046779
8 Locked QAM256 7 567000000 Hz 1.5 dBmV 34.0 dB 875860240 11626260 23857192
9 Locked QAM256 8 573000000 Hz 1.6 dBmV 35.3 dB 875179409 11789671 24386663
10 Locked QAM256 9 579000000 Hz 1.7 dBmV 39.1 dB 874541514 12024023 24794520
11 Locked QAM256 10 585000000 Hz 1.5 dBmV 34.2 dB 873370817 12224296 25768195
12 Locked QAM256 11 591000000 Hz 1.7 dBmV 30.5 dB 872226914 12479957 26660169
13 Locked QAM256 12 597000000 Hz 2.1 dBmV 28.6 dB 871399158 12668437 27303553
14 Locked QAM256 13 603000000 Hz 2.2 dBmV 32.5 dB 870207229 12931493 28236643
15 Locked QAM256 14 609000000 Hz 2.0 dBmV 39.3 dB 869311904 13160307 28906921
16 Locked QAM256 15 615000000 Hz 1.9 dBmV 31.0 dB 867890500 13470593 30021500
17 Locked QAM256 16 621000000 Hz 2.2 dBmV 41.5 dB 866608219 13770924 31028572
18 Locked QAM256 17 483000000 Hz 3.0 dBmV 40.2 dB 891762081 7613961 12031696
19 Locked QAM256 19 495000000 Hz 2.8 dBmV 38.3 dB 889808484 8120230 13484770
20 Locked QAM256 20 501000000 Hz 2.8 dBmV 30.2 dB 889195686 8301709 13920593
21 Locked QAM256 21 507000000 Hz 2.7 dBmV 35.6 dB 888341083 8513532 14567930
22 Locked QAM256 22 513000000 Hz 2.7 dBmV 28.8 dB 887499693 8738158 15189322
23 Locked QAM256 23 519000000 Hz 2.4 dBmV 36.5 dB 885792066 9159273 16479875
24 Locked QAM256 24 525000000 Hz 2.2 dBmV 36.3 dB 884794955 9429620 17211154
25 Locked QAM256 25 627000000 Hz 2.1 dBmV 41.5 dB 866240243 13864651 31334570
26 Locked QAM256 26 633000000 Hz 2.2 dBmV 40.9 dB 865436360 14042546 31964110
27 Locked QAM256 27 639000000 Hz 1.8 dBmV 41.4 dB 864004694 14383748 33058518
28 Locked QAM256 33 459000000 Hz 3.3 dBmV 34.6 dB 896195245 6426036 8829227
29 Locked QAM256 34 465000000 Hz 3.5 dBmV 34.8 dB 894994536 6766480 9693298
30 Locked QAM256 35 471000000 Hz 3.3 dBmV 30.5 dB 894330691 6950482 10175059
31 Locked QAM256 36 477000000 Hz 3.2 dBmV 33.6 dB 893166524 7264150 11027946
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0

<tabindex=-1>Upstream Bonded Channels</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power
1 Locked ATDMA 5 35800000 Hz 47.0 dBmV
2 Locked ATDMA 6 29400000 Hz 46.5 dBmV
3 Locked ATDMA 7 23000000 Hz 46.0 dBmV
4 Locked ATDMA 8 16600000 Hz 44.8 dBmV
5 Not Locked Unknown 0 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Hz 0.0 dBmV

<tabindex=-1>Downstream OFDM Channels</tabindex=-1>
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier Number Range Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked 0, 1, 255 37 690000000 Hz 2.2 dBmV 40.0 dB 1228 ~ 2867 10419675441 10268671188 0
2 Not Locked 0, 255 0 0 Hz 3.1 dBmV 0.0 dB 0 ~ 4095 0 0 0

<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked Unknown 0 0 Hz 0 dBmV
2 Not Locked Unknown 0 0 Hz 0 dBmV
Official Employee

Re: DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

Hello hotshot90, thank you for taking the time out to create a post on our forum. I replied to your private message please reach back out to me there for further assistance. 


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Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.
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Frequent Visitor

Re: DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

Replied to you in a PM. 

Frequent Visitor

Re: DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

@ComcastAmir Any update?

Official Employee

Re: DOCSIS 3.1 issues since upgrading (t3/t4/mdd timeouts)

hotshot90 wrote: Replied to you in a PM. 

 

I replied back to your PM, let's continue our troubleshooting there. 


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Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!