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3 Messages

Friday, June 19th, 2020 8:00 PM

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Arris SBG8300 DOCSIS 3.1 only getting 31 Channel Downstream and 5 Channels Upstream

Hello -

 

I am not getting Gigabit speed with my Arris SBG8300 DOCSIS 3.1 modem and I also have to restart the modem once or twice a week due to lost connection. This happened in the recent month or so.

 

After calling Xfinity to troubleshoot the issue they suggested I should call Arris (modem manufacturer) as well since Xfinity was not able to identify the issue. I went through a 30min diagnostic with an Arris technician to check on various areas (power level, SNR level, etc on both the downstream and upstream data of the modem.)

 

Arris technician found the issue is most likely due to the downstream only has 31 channels (instead of  32) and upstream only has 5 channels (instead of 8). This will slow down the connection and cause stability issues with the modem. 

 

Arris said I should call Xfinity to check on the quality of the cables and connections outside the house and inside the house to make sure they are in good condition. 

 

Does anyone have a similar issue with their Gigabit internet? How did you resolve this? Anyone from Xfinity on this forum that is knowledgeable on DOCSIS 3.1 can help out?

 

Thank you.

 

 

 

 

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Expert

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111.6K Messages

5 years ago

Those amounts of DOCSIS 3.0 channels are normal. Are you seeing an "other" / DOCSIS 3.1 / OFDM downstream channel ? That's the only one that they deliver their gigabit speed tier by ?

Expert

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111.6K Messages

5 years ago

Arris is conning you about the channels need to be even.... They have been conning Comcast customers about a few different things lately.

 

And Comcast currently does not offer more than five upstream channels.

 

And most systems used to offer 32 downstream channels (some still do) but most knocked it back to 31 when they implemented the DOCSIS 3.1 / OFDM downstream channel that delivers their gigabit speed tier.

New Poster

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3 Messages

5 years ago

Hello -

 

Thank you for your feedback. Actually, internet speed is less of my concern. As long as I am getting above 500Mbps I am fine even though I am paying for gigabit speed. My main concern is the stability of my connection (intermittent drop-offs).

 

Per Arris' technical support, the downstream and upstream channel bonding values need to be even numbers since the channels work in pairs. Have an odd number of channels will cause issue.  I am not an expert on this but I can call Arris again to talk to another technical staff to get a second opinion. 

 

Are you saying less than 32 downstream and less than 8 upstream channels bonding is normal for Xfinity service on a DOCSIS 3.1 modem? 

 

Thank you.

 

 

 

 

Expert
‎06-20-2020 12:56 AM
Re: Arris SBG8300 DOCSIS 3.1 only getting 31 Channel Downstream and 5 Channels Upstream

Those amounts of DOCSIS 3.0 channels are normal. Are you seeing an "other" / DOCSIS 3.1 / OFDM downstream channel ? That's the only one that they deliver their gigabit speed tier by ?

 

 

New Poster

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3 Messages

5 years ago

Hello -

 

Thank you for the feedback. Uh, Arris seemed to be playing games and blaming Xfinity ; )

 

Not sure where the intermittent drop off issue came from. Xfinity, modem, etc?

 

Xfinity had been monitoring my connection since yesterday because I called them multiple times this week. So far there is no drop off yet. Speed had been around 950Mbps now which is good since I was getting less previously. Hopefully, everything stays as it is now...

 

Thank you.

 

 

Expert
‎06-20-2020 06:54 PM
Re: Arris SBG8300 DOCSIS 3.1 only getting 31 Channel Downstream and 5 Channels Upstream

Arris is conning you about the channels need to be even.... They have been conning Comcast customers about a few different things lately.

 

And Comcast currently does not offer more than five upstream channels.

 

And most systems used to offer 32 downstream channels (some still do) but most knocked it back to 31 when they implemented the DOCSIS 3.1 / OFDM downstream channel that delivers their gigabit speed tier.

Expert

 • 

111.6K Messages

5 years ago

Quite welcome ! Hope that things hold up for you. Good luck !
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