Bonded Download Channels

I wouldn't be concerned so much about the number of download channels in your area as I would be about getting a modem that is compatible with Comcast/Xfinity.    I personally would suggest being forward thinking and getting a modem that is also DOSCIS 3.1 compliant.    DOSCIS 3.1 supports download speeds up to 10Gb.   My old SB6121 is a 4x4 with a maxium download speed of 172 Mb/s.  An 8x32 modem should cover all offerings in your area with maybe the exception of 1Gb and I think that is only becuase the 1Gb requires special equipment.   I see a $500 equipment fee for 1Gb service in my area so that makes me think service may be optical.   I know my 8x32 modem is using all download channels yet my service plan is only 100Mb/s.    

Look at the offerings in your area, decide on what you want today as a service plan, what you will want in the future, and plan accordingly.    Even if your area has less than 32 download channels, and I doubt that's the case, I suspect all areas have 32 channels unless they are serviced by really old equipment, getting an 8x32 will work for you.   If you never, ever see wanting more than 500-600 Mb/s you can go with 8x24.

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@Clifford1234 wrote:

 Current modem is having issues .

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How do you know it's the modem ? Maybe it's the connection to the system ?

Please describe the "issues" that you are having.

What do the modem's signal stats look like ? Try getting them here http://192.168.100.1 or here http://10.0.0.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

What is the exact make and model number of the modem ?

Is there a router / WiFi in the mix ? 

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@cxrider wrote:

 DOSCIS 3.1 supports download speeds up to 10Gb.   

 

Yes but Comcast currently offers only a single 192 MHz  / DOCSIS 3.1 / OFDM modulated downstream channel which has a 1.89 Gigabit throughput capability, but they currently offer only a 1 Gigabit speed tier. Me thinks that it will be a long long time (if ever) before they ever free up / have enough of an RF frequency spectrum to be able to deliver 10 Gig.

 

An 8x32 modem should cover all offerings in your area with maybe the exception of 1Gb and I think that is only becuase the 1Gb requires special equipment.  

 

Comcast will only deliver the 1 Gigabit speed tier via the DOCSIS 3.1 / OFDM modulated downstream channel, not via the multiple bonded QAM 256 modulated channels, although having enough of them bonded together are theoretically capable.

 

I see a $500 equipment fee for 1Gb service in my area so that makes me think service may be optical.

 

1 Gigabit is not optical fiber, it's DOCSIS / coax. Their "Gigabit Pro" (2 gigabit) service offering is delivered via FTTH (Fiber To The Home).

 

I suspect all areas have 32 channels 

 

Many areas that have upgraded their system to DOCSIS 3.1 are now offering only 31 bonded QAM 256 / DOCSIS 3.0 downstream channels.

 

DOCSIS 4.0 / full duplex is on the horizon.

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@Xephyr wrote:

@EG ,

 

Quick question. if 1gbps is delievered using the OFDM downloaded channel. what are those 32 QAM256 channels for.

 

All of the other speed tiers / traffic.

 

Reason I ask is because I see that my modem only locks 10 QAM256 channels and the rest of the frequencies are simply not locked. I tried several ways to make sure I remove unnecessary splitters, connections to have enough signals...etc. One time I log in after an hours or so I saw 22 locked QAM256 channels. While i don't see any performance difference (940 Download/40 upload on wired LAN), I do wonder why sometimes it has more channels. Also one time I set the starting frequency to the lowest of the 10 usually locked frequencies, once modem reboot, it started with 22 lockec QAM256 cannels. Just wondering if that's normal. 

 

Thank you very much for clarification!

 

Poor connection quality, noise ingress into the lines somewhere can cause the unbonding of channels.

 

And the reason i started to check these is because my modem sometimes drops packets and Netflix starts to show me 0.3mpbs low-res videos... and sometimes completely stops, until I reboot the modem. Started at once a month to once a week, and recently several times a day. (and mostly Friday and weekends seems like more often.) After removing some splitters and connect more direcly cable modem to the incoming coaxial cable, the 4 upstream power dropped from 50dBmv to around 41.3dBmv. Hopefully this solve the intemittnent connection package drop problem.

 

41 dB of upstream power is right within the desired *sweet spot* of 40 to 45 dB !

 

Please feel free to create a new topic of your own here on this board detailing your issue. 10 month old dead thread now being closed.

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@EG ,

Quick question. if 1gbps is delievered using the OFDM downloaded channel. what are those 32 QAM256 channels for. Reason I ask is because I see that my modem only locks 10 QAM256 channels and the rest of the frequencies are simply not locked. I tried several ways to make sure I remove unnecessary splitters, connections to have enough signals...etc. One time I log in after an hours or so I saw 22 locked QAM256 channels. While i don't see any performance difference (940 Download/40 upload on wired LAN), I do wonder why sometimes it has more channels. Also one time I set the starting frequency to the lowest of the 10 usually locked frequencies, once modem reboot, it started with 22 lockec QAM256 cannels. Just wondering if that's normal. 

Thank you very much for clarification!

And the reason i started to check these is because my modem sometimes drops packets and Netflix starts to show me 0.3mpbs low-res videos... and sometimes completely stops, until I reboot the modem. Started at once a month to once a week, and recently several times a day. (and mostly Friday and weekends seems like more often.) After removing some splitters and connect more direcly cable modem to the incoming coaxial cable, the 4 upstream power dropped from 50dBmv to around 41.3dBmv. Hopefully this solve the intemittnent connection package drop problem.

Below is my Netgear CM1200 channel status.