S

Visitor

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4 Messages

Wed, Jun 9, 2021 10:52 AM

Random Disconnects

Hello,

I am currently using the C7800 on my home network. The disconnects aren't a lot but they seem more often than they should be. I see conflicting information between Netgear and Xfinity specs for channel levels. I had a disconnect last night. I live in an apartment building so I wonder if it's going to be harder to diagnose. Thank you for any help in advance

Here's some info:

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 675000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD IPv6 only

Responses

Accepted Solution

EG

Expert

 • 

87.1K Messages

7 d ago

The power levels are out of spec. 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 !

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Visitor

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4 Messages

@EG I will check the line from the wall to the router for damage as that's all I can do it seems short of booking a tech. Do you have any idea what the tech will check for since it's an apartment building? My other question is which power levels? The upstream or down stream?


Thanks for your reply

EG

Expert

 • 

87.1K Messages

Yes. Both the up and down power levels are out of spec. It's a general connection impairment somewhere that is affecting both. 

If none of those tips apply, then yes, you'll need a tech out to investigate / correct the problem. 

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 !

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Visitor

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4 Messages

@EG Would you mind posting the recommended specs? So I can use to show when I'm talking to xfinity support? With a link by chance? Thanks for your posts!

EG

Expert

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87.1K Messages

Yes. These are from the pinned troubleshooting tips topic right at the top of this board;

 

Specification      Min             Max
Downstream Power Level    
Cable Modems -10dBmV +10dBmV
Gateways and EMTAs -7dBmV +7dBmV
Downstream Signal to Noise Ratio 35dB -
Upstream Power Level +35dBmV +50dBmV
Upstream Signal to Noise Ratio 31dB -
Upstream Receive Power -2dBmV +2dBmV
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Official Employee

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249 Messages

Hello and thank you for taking the time to reach out to us here on our Xfinity Forums. I'm truly sorry to hear that you've been experiencing disconnects with your service. I would love to look into the signals on our end and assist you with resolving the concerns. Please send us a private message with your name and service address to Xfinity Support by clicking the chat icon at the top right of the page.

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EG

Expert

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87.1K Messages

5 d ago

@schyler_123 @ComcastBillie 

Please post any possible solutions for the issue here in the open forums so that all readers here may benefit from the exchange / info. This is in keeping with the spirit for which these public help forums were originally intended. Thank you.

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Visitor

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4 Messages

1 d ago

I had a tech out yesterday afternoon. The person who had wired my apartment for internet had installed the splitter backwards causing serious issues with signal. As far as I can tell, everything is perfectly running. I have yet to have any drops in speed.

To anyone who also had this issue, if your router says the signal is out of spec from xfinity and you're sure it's not the wires you can access and it had to do with the install of wiring, definitely have a tech come out! Thank you to all who helped get this remedied quickly with great information. The tech even helped explain what was wrong and what he was looking for, it was perfect!

EG

Expert

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87.1K Messages

1 d ago

@schyler_123 

Glad you got it squared away ! Now closing your topic.

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