HankV's profile

Frequent Visitor

 • 

15 Messages

Fri, Oct 22, 2021 12:46 PM

DOCSIS3.0 works fine , 3.1 keeps droping

Xfinity replaced defective lines at my house and checked all connections and signal levels internally. This issue started about 3 weeks ago. Rebooting the modem will reconnect 3.1 and it stays for hours. No errors are reported on the 3.0 channels, and this particular modem always reports errors (the case since day one last year) but up to now had no 3.1 issues.  Modem is an Arris SB8200. Details follow in the rest of this message. Channel ID 25 is the OFDM 3.1 channel (told to me by Arris who reviewed this information).

tandard Specification Compliant Docsis 3.1
Hardware Version 6
Software Version AB01.02.053.05_051921_193.0A.NSH

Procedure Status Comment
Acquire Downstream Channel 519000000 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
13 Locked QAM256 519000000 Hz -4.3 dBmV 42.3 dB 0 0
1 Locked QAM256 441000000 Hz -4.3 dBmV 42.2 dB 17 0
2 Locked QAM256 453000000 Hz -4.6 dBmV 42.0 dB 33 0
3 Locked QAM256 459000000 Hz -4.6 dBmV 42.1 dB 24 0
4 Locked QAM256 465000000 Hz -4.4 dBmV 42.1 dB 32 0
5 Locked QAM256 471000000 Hz -4.5 dBmV 42.1 dB 28 0
6 Locked QAM256 477000000 Hz -4.6 dBmV 42.0 dB 2 0
7 Locked QAM256 483000000 Hz -4.3 dBmV 42.3 dB 8 0
8 Locked QAM256 489000000 Hz -4.3 dBmV 42.2 dB 32 0
9 Locked QAM256 495000000 Hz -4.1 dBmV 42.4 dB 27 0
10 Locked QAM256 501000000 Hz -4.3 dBmV 42.2 dB 41 1
11 Locked QAM256 507000000 Hz -4.1 dBmV 42.3 dB 26 0
12 Locked QAM256 513000000 Hz -4.0 dBmV 42.2 dB 32 1
14 Locked QAM256 525000000 Hz -4.6 dBmV 42.1 dB 0 0
15 Locked QAM256 531000000 Hz -4.5 dBmV 42.2 dB 26 0
16 Locked QAM256 537000000 Hz -4.7 dBmV 42.0 dB 0 0
17 Locked QAM256 543000000 Hz -4.7 dBmV 42.0 dB 10 0
18 Locked QAM256 555000000 Hz -4.8 dBmV 41.8 dB 33 0
19 Locked QAM256 561000000 Hz -4.7 dBmV 42.0 dB 12 0
20 Locked QAM256 567000000 Hz -4.9 dBmV 41.9 dB 9 0
21 Locked QAM256 573000000 Hz -4.8 dBmV 41.9 dB 1 0
22 Locked QAM256 579000000 Hz -5.0 dBmV 41.8 dB 5 0
23 Locked QAM256 585000000 Hz -5.0 dBmV 41.8 dB 34 0
24 Locked QAM256 591000000 Hz -4.8 dBmV 41.8 dB 17 0
25 Locked Other 693000000 Hz -4.9 dBmV 40.0 dB 918465283 0
26 Not Locked QAM256 0 Hz 0.0 dBmV 42.1 dB 0 0
27 Locked QAM256 597000000 Hz -4.5 dBmV 42.0 dB 14 0
28 Locked QAM256 603000000 Hz -4.4 dBmV 42.0 dB 0 0
29 Locked QAM256 609000000 Hz -4.5 dBmV 41.8 dB 0 0
30 Locked QAM256 615000000 Hz -4.9 dBmV 41.7 dB 1 0
31 Locked QAM256 621000000 Hz -5.0 dBmV 41.6 dB 12 0
32 Locked QAM256 627000000 Hz -5.0 dBmV 41.9 dB 0 0


Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 9 Locked SC-QAM Upstream 36500000 Hz 6400000 Hz 50.0 dBmV
2 10 Locked SC-QAM Upstream 30100000 Hz 6400000 Hz 50.0 dBmV
3 11 Locked SC-QAM Upstream 23700000 Hz 6400000 Hz 49.0 dBmV
4 12 Locked SC-QAM Upstream 17300000 Hz 6400000 Hz 49.0 dBmV


Accepted Solution

EG

Expert

 • 

90.6K Messages

1 m ago

The upstream power is on the high side and it may be intermittently fluctuating even higher to out of spec levels. The downstream power is a bit low / weak as well. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are there 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, 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, kinks, sharp bends, etc.

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 !

HankV

Frequent Visitor

 • 

15 Messages

@EG

Thanks for getting back to me. What I have installed was done by the Xfinity Installer, including the splitters which he replaced along with all the wiring. The upstream has been high since day one (including with two previous modems in the same location...been here since 2007).   Beats me what's going on, since all the obvious things were replaced. I rebooted the modem around 2p today and its still connected. Very strange. BTW- Nothing wrong with 3.0, and speeds are fine.

EG

Expert

 • 

90.6K Messages

If there is nothing that you can do to improve the connection, then as was stated, you'll need to get the techs reinvolved.

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.


Good luck with it !

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XfinityAbbie

Official Employee

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691 Messages

@HankV Hello and thank you for taking the time to reach out. I am sorry to hear you are having issues with your services. I would like to assist in any way I can. 

 

Please send a private message by clicking the direct messaging chat icon in the upper right corner of the page, click on the pen and paper icon, then enter “Xfinity Support” in the “To” section. Please include your name and address and I'll be happy to help.

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.
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