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user_vitfmi
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Friday, April 18th, 2025 1:55 PM

No DOCSIS 3.1 signal on Arris SB8200 - newly provisioned

Hello. I recently switched out my older SB6183 modem for an SP8200, because I have a 600mbs plan but the Xfinity app said my max download speed was only 400mbs. I connected the new modem and activated it on my account through the Xfinity app last night. However, I am not showing any DOCSIS 3.1 connection according to the status lights. I have tried to reboot the modem again this morning, and still no luck. I am not sure if I am missing something, but would love some help. Below is my modem status and channels.

Procedure Status Comment
Acquire Downstream Channel 537000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK
Security Enabled BPI+
DOCSIS Network Access Enabled Allowed

Downstream Bonded Channels
Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
20 Locked 256QAM 537000000 Hz -4 dBmV 38 dB 0 0
28 Locked 256QAM 585000000 Hz -5 dBmV 38 dB 0 0
36 Locked 256QAM 633000000 Hz -6 dBmV 38 dB 0 0
44 Locked 256QAM 681000000 Hz -7 dBmV 38 dB 0 0
13 Locked 256QAM 489000000 Hz -4 dBmV 38 dB 0 0
14 Locked 256QAM 495000000 Hz -4 dBmV 38 dB 0 0
15 Locked 256QAM 507000000 Hz -4 dBmV 38 dB 0 0
16 Locked 256QAM 513000000 Hz -4 dBmV 38 dB 0 0
17 Locked 256QAM 519000000 Hz -4 dBmV 38 dB 0 0
18 Locked 256QAM 525000000 Hz -4 dBmV 38 dB 0 0
19 Locked 256QAM 531000000 Hz -4 dBmV 38 dB 0 0
21 Locked 256QAM 543000000 Hz -4 dBmV 38 dB 0 0
22 Locked 256QAM 549000000 Hz -4 dBmV 38 dB 0 0
23 Locked 256QAM 555000000 Hz -4 dBmV 38 dB 0 0
24 Locked 256QAM 561000000 Hz -4 dBmV 38 dB 0 0
25 Locked 256QAM 567000000 Hz -4 dBmV 38 dB 0 0
26 Locked 256QAM 573000000 Hz -5 dBmV 38 dB 0 0
27 Locked 256QAM 579000000 Hz -5 dBmV 38 dB 0 0
29 Locked 256QAM 591000000 Hz -5 dBmV 38 dB 2 0
30 Locked 256QAM 597000000 Hz -5 dBmV 38 dB 2 0
31 Locked 256QAM 603000000 Hz -6 dBmV 38 dB 7 0
32 Locked 256QAM 609000000 Hz -7 dBmV 38 dB 0 0
33 Locked 256QAM 615000000 Hz -7 dBmV 37 dB 0 0
34 Locked 256QAM 621000000 Hz -8 dBmV 37 dB 0 0
35 Locked 256QAM 627000000 Hz -7 dBmV 37 dB 0 0
37 Locked 256QAM 639000000 Hz -6 dBmV 38 dB 0 0
38 Locked 256QAM 645000000 Hz -6 dBmV 38 dB 0 0
39 Locked 256QAM 651000000 Hz -6 dBmV 38 dB 0 0
40 Locked 256QAM 657000000 Hz -6 dBmV 38 dB 0 0
41 Locked 256QAM 663000000 Hz -6 dBmV 38 dB 0 0
42 Locked 256QAM 669000000 Hz -6 dBmV 38 dB 0 0
43 Locked 256QAM 675000000 Hz -7 dBmV 38 dB 0 0
193 Locked OFDM PLC 805000000 Hz -9 dBmV 38 dB 13981358 1


Upstream Bonded Channels
Channel ID Lock Status US Channel Type Frequency Width Power
5 Locked SC-QAM 40400000 Hz 3200000 47.0 dBmV
6 Locked SC-QAM 10400000 Hz 3200000 49.0 dBmV
1 Locked SC-QAM 16400000 Hz 6400000 48.0 dBmV
4 Locked SC-QAM 35600000 Hz 6400000 48.0 dBmV
3 Locked SC-QAM 29200000 Hz 6400000 48.0 dBmV
2 Locked SC-QAM 22800000 Hz 6400000 48.0 dBmV


Date Time Event Level Description
18/04/2025 06:30:11
notice
GUI Login Status - Login Success from LAN interface; client ip=[75.71.69.57];CM-CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:19:57
notice
REGISTRATION COMPLETE - Waiting for Operational status;CM-;CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:19:55
critical
No Ranging Response received - T3 time-out;CM7;CMTS-S=1.1;CM-VER=3.1;
18/04/2025 06:19:54
warning
RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-;CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:19:49
critical
Config File Rejected due to Invalid or Unexpected TLV 11;CM-;CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:19:49
notice
TLV-11 - unrecognized OID;CM-CMTS-CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:19:47
warning
MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-;CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:19:47
notice
CMSTATUS:DS_Diplexer_Mode_Change_Ignored:[TLV-84.3], [1002MHZ];CM-;CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:19:47
notice
CMSTATUS:DS_Diplexer_Mode_Change_Ignored:[TLV-84.2], [108MHZ];CM-;CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:19:47
notice
CMSTATUS:US_Diplexer_Mode_Change:[TLV-84.1], [5-42MHZ];CM-00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:25
notice
CMSTATUS:DS_Diplexer_Mode_Change_Ignored:[TLV-21.3], [1002MHZ];CM-:02:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:25
notice
CMSTATUS:DS_Diplexer_Mode_Change_Ignored:[TLV-21.2], [258MHZ];CM-02:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:25
notice
CMSTATUS:US_Diplexer_Mode_Change:[TLV-21.1], [5-42MHZ];CM-2:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:25
notice
CMSTATUS:US_Diplexer_Mode_Change:[TLV-9], [5-85MHZ];CM-02:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:24
notice
Honoring MDD; IP provisioning mode = IPv6;CM-;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:20
notice
CMSTATUS:DS_Diplexer_Mode_Change:Init, [108-1002MHZ];CM-;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:20
notice
CMSTATUS:US_Diplexer_Mode_Change:Init, [5-42MHZ];CM-CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:17:40
critical
Unicast Ranging Received Abort Response - initializing MAC;CM-00;CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:17:38
notice
Cable Modem Reboot from SNMP;CM-:02:00;CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:08:38
notice
CM-STATUS message sent. Event Type Code: 5; Chan ID: 43; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-:02:00;CM-QOS=1.1;CM-VER=3.1;
18/04/2025 06:04:58
notice
GUI Login Status - Login Success from LAN interface; client ip=[75.71.69.57];CM-;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:56:03
notice
REGISTRATION COMPLETE - Waiting for Operational status;CM-02:00;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:55:59
critical
No Ranging Response received - T3 time-out;CM-02:00;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:55:58
warning
RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-2:00;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:55:53
critical
Config File Rejected due to Invalid or Unexpected TLV 11;CM-;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:55:53
notice
TLV-11 - unrecognized OID;CM-0;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:55:51
warning
MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-02:00;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:55:51
notice
CMSTATUS:DS_Diplexer_Mode_Change_Ignored:[TLV-84.3], [1002MHZ];CM-;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:55:51
notice
CMSTATUS:DS_Diplexer_Mode_Change_Ignored:[TLV-84.2], [108MHZ];CM-02:00;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:55:51
notice
CMSTATUS:US_Diplexer_Mode_Change:[TLV-84.1], [5-42MHZ];CM-;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:24
notice
CMSTATUS:DS_Diplexer_Mode_Change_Ignored:[TLV-21.3], [1002MHZ];CM-02:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:24
notice
CMSTATUS:DS_Diplexer_Mode_Change_Ignored:[TLV-21.2], [258MHZ];CM-0;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:24
notice
CMSTATUS:US_Diplexer_Mode_Change:[TLV-21.1], [5-42MHZ];CM-02:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:24
notice
CMSTATUS:US_Diplexer_Mode_Change:[TLV-9], [5-85MHZ];CM-2:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:24
notice
Honoring MDD; IP provisioning mode = IPv6;CM-02:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:20
notice
CMSTATUS:DS_Diplexer_Mode_Change:Init, [108-1002MHZ];CM-;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 17:01:20
notice
CMSTATUS:US_Diplexer_Mode_Change:Init, [5-42MHZ];CM-;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:53:43
critical
Unicast Ranging Received Abort Response - initializing MAC;CM-0;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:53:41
notice
Cable Modem Reboot from SNMP;CM-02:00;CM-QOS=1.1;CM-VER=3.1;
17/04/2025 21:52:51
notice
CM-STATUS message sent. Event Type Code: 5; Chan ID: 27; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-0;CM-QOS=1.1;CM-VER=3.1;

Question

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Updated 

2 days ago

 • Edited

37

3

EG

Expert

 • 

110K Messages

6 days ago

Regardless of what the indicator lights may show, the signal status output shows that a downstream DOCSIS 3.1 (OFDM) channel is indeed locked in;

193 Locked OFDM PLC 805000000 Hz -9 dBmV 38 dB 13981358 1

However, the signal strength of it is on the low / weak side (out of spec). All of the other bonded downstream QAM channels are on the low / weak side as well. And the upstream channel power levels are also borderline / too high. There is a connection impairment somewhere. This should be addressed regardless of any thing else.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage from Home Depot, Target, Wal-Mart, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, animal chews.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.


Good luck with it !

(edited)

3

0

user_vitfmi

4 Messages

What should the signal strength be?

(edited)

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3 days ago

0

XfinityRay

Official Employee

 • 

2.7K Messages

user_vitfmi We like the upstream power at 30-50 dBmV and downstream power at -10 to 10 dBmV. @EG has some fantastic help above! Do you have any splitters along your coax line between the wall outlet and the modem? 

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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3 days ago

0

user_vitfmi

4 Messages

Okay I had the line going through a whole home wiring system. I have removed that and now wired directly to the modem. Here are my current levels; however, my modem still doesn't show DOCSIS 3.1. Also, my account still shows that I have plan speeds of 600 Mbps, but the Xfinity app still only shows download speeds up to 400 Mbps. 

20 Locked 256QAM 537000000 Hz 5 dBmV 40 dB 0 0
28 Locked 256QAM 585000000 Hz 4 dBmV 38 dB 8 0
36 Locked 256QAM 633000000 Hz 4 dBmV 38 dB 0 0
44 Locked 256QAM 681000000 Hz 3 dBmV 38 dB 3 0
13 Locked 256QAM 489000000 Hz 5 dBmV 40 dB 0 0
14 Locked 256QAM 495000000 Hz 5 dBmV 40 dB 0 0
15 Locked 256QAM 507000000 Hz 5 dBmV 40 dB 0 0
16 Locked 256QAM 513000000 Hz 5 dBmV 40 dB 0 0
17 Locked 256QAM 519000000 Hz 5 dBmV 40 dB 0 0
18 Locked 256QAM 525000000 Hz 5 dBmV 40 dB 0 0
19 Locked 256QAM 531000000 Hz 6 dBmV 40 dB 0 0
21 Locked 256QAM 543000000 Hz 5 dBmV 40 dB 0 0
22 Locked 256QAM 549000000 Hz 5 dBmV 38 dB 0 0
23 Locked 256QAM 555000000 Hz 5 dBmV 38 dB 0 0
24 Locked 256QAM 561000000 Hz 5 dBmV 38 dB 0 0
25 Locked 256QAM 567000000 Hz 5 dBmV 38 dB 0 0
26 Locked 256QAM 573000000 Hz 5 dBmV 38 dB 0 0
27 Locked 256QAM 579000000 Hz 4 dBmV 38 dB 1 0
29 Locked 256QAM 591000000 Hz 4 dBmV 38 dB 1 0
30 Locked 256QAM 597000000 Hz 4 dBmV 38 dB 2 0
31 Locked 256QAM 603000000 Hz 4 dBmV 38 dB 6 0
32 Locked 256QAM 609000000 Hz 4 dBmV 38 dB 1 0
33 Locked 256QAM 615000000 Hz 4 dBmV 38 dB 0 0
34 Locked 256QAM 621000000 Hz 4 dBmV 38 dB 0 0
35 Locked 256QAM 627000000 Hz 4 dBmV 38 dB 0 0
37 Locked 256QAM 639000000 Hz 4 dBmV 38 dB 0 0
38 Locked 256QAM 645000000 Hz 4 dBmV 38 dB 0 0
39 Locked 256QAM 651000000 Hz 4 dBmV 38 dB 0 0
40 Locked 256QAM 657000000 Hz 4 dBmV 38 dB 0 0
41 Locked 256QAM 663000000 Hz 4 dBmV 38 dB 3 0
42 Locked 256QAM 669000000 Hz 4 dBmV 38 dB 0 0
43 Locked 256QAM 675000000 Hz 3 dBmV 38 dB 0 0
193 Locked OFDM PLC 805000000 Hz 1 dBmV 40 dB 1398140202 122


Upstream Bonded Channels
Channel ID Lock Status US Channel Type Frequency Width Power
6 Locked SC-QAM 10400000 Hz 3200000 40.0 dBmV
1 Locked SC-QAM 16400000 Hz 6400000 39.0 dBmV
5 Locked SC-QAM 40400000 Hz 3200000 39.0 dBmV
4 Locked SC-QAM 35600000 Hz 6400000 39.0 dBmV
3 Locked SC-QAM 29200000 Hz 6400000 39.0 dBmV
2 Locked SC-QAM 22800000 Hz 6400000 40.0 dBmV


Current System Time:Mon Apr 21 08:20:15 2025

(edited)

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3 days ago

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EG

Expert

 • 

110K Messages

2 days ago

The stats are much better / well within specs now ! And it's still showing that a downstream DOCSIS 3.1 / OFDM channel is locked in regardless of the receive light. It may be a firmware glitch. Try hard resetting the 8200 back to factory defaults by pressing and holding in the recessed reset button on the rear for 30 seconds and see. This can sometimes clear up some weird behavior issues.

Is there a router / WiFi in the mix here ? The speeds may be an issue with the modem's provisioning. Try contacting a rep and have them confirm that the provisioning is correct and complete. And that the correct configuration / bootfile is being pushed to the modem.

2

0

user_vitfmi

4 Messages

Okay well I tried hard resetting the modem and still seeing the same thing. I'm going straight from my modem to a firewala router and then into a eero network set up in bridge mode. I will reach out to Comcast and see if they can make sure the provisioning is correct. Is there something particular I should ask them on the provisioning? 

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2 days ago

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XfinityEva

Official Employee

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1.6K Messages

Thank you @EG! 

 

 

user_vitfmi We can check that for you here and circle back with the findings. Just send us a direct message with your full name and the service address please. 
 
To send a direct message: 
 
  • Make sure you are signed in here in the Xfinity Forum. Click "Sign In" if necessary
  • Click the "Direct Message" icon (square chat icon in the upper right corner of your screen next to the bell 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.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

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2 days ago

EG

Expert

 • 

110K Messages

2 days ago

Quite welcome @XfinityEva !

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