SB8200 - Successful Set-Up but No Internet...

I should’ve mentioned….

All lights are green except the Receive light, which is blue - “Blue* (ON): indicates a bonded downstream (receive data) channel connection”

What’s the difference between a downstream channel connection & a bonded downstream channel connection?

Could you provide screenshots of your “Status” page? It would help to see the Startup Procedure section, the Downstream Bonded Channel section, and Upstream Bonded Channel section. Any unusual messages in the event log (T-3 timeouts?)

I would expect you to see 32 Bonded Downstream Channels labled QAM256 (basically data) and one for OFDM PLC (basically signalling control).

https://www.commscope.com/blog/2015/the-importance-of-channel-bonding/#:~:text=Channel%20bonding%20combines%20multiple%20channels,modem's%20highway%20can%20comfortably%20support.

Man, thanks, but this is all over my head…  I thought I could open the box, hook it up, let Xfinity do their thing, then get back to work at a faster rate than my previous setup allowed…  I’ll see if I can figure out how to get what you requested.

Sometimes everything is smooth, and sometimes it isn’t.  I’ll help if I can.

Not sure exactly how you have things set up, but for now, the fewer variables the better.

I would connect your PC directly to the SB8200 using an ethernet connection to the top port. Then, restart the modem. Once it is up, you should be able to open (for instance) a Chrome browser session and go to 192.168.100.1 which will bring up a login page. If you have never made any changes, then your login is ‘admin’ and your password is the last 8 digits of your serial number. Once you get in, you’ll be able to see the status and can cut and past the information directly into a chat window.

What are you using for a router?

Thanks!  I appreciate that.  I’ll try that when I have a moment.  

RE: What are you using for a router?

No router, connecting my PC directly to the modem via ethernet cable.  

Okay, I plugged the cable back into the modem and went to 192.168.100.1, but I wasn’t given the option of logging in….

I’ve attached screenshots of the “Event Log” & the “Status”.

 [edit: removed image with personal information] 

There is definitely something wrong with the  Downstream signal. Is there any sort of splitter, filter, or amplifier between where the coax comes in to the house, and the modem? If you look at my signal, everything is within 2 dBmV. Your signal strenth varies widely with frequency. Channel 33 is probably your OFDM channel, and the signal is low, SNR is poor, corrected errors are high (but that’s common on OFDM) and the uncorrected errors exceed corrected by 2 to 1 which is a bad sign. Additionally, those CMTS errors in the log are an indicator (basically a warning) of signal issues. If your ISP looks at that information (they can) they’ll see there is a problem. The only question is, is the problem inside your residence (your problem) or prior to the demarc (their box). Good be a bad cable to your residence, a loose connection at the box, damaged cable inside, or a bad connector. Basically, you’ll need to work from the modem to the  demarc and check everything you have, and have the ISP send a tech to confirm you have a good signal at the box. 

Thorough analysis - thank you for taking the time to do that! 

We have only 1 splitter in the house - it’s right off the main line & takes the signal to our Xfinity Gateway & (now) this new modem. 

My work PC has been wired directly into an Xfinity XFi Pod via ethernet cable (& is right now), which works okay most of the time but is often too slow for my taste (I run multiple web-based applications & programs while working) - which is why I had the idea that this ARRIS modem would help to more consistently speed things up for me.  

Our phones, TV’s, & laptops all work just fine on our network via the Xfinity Gateway & XFi Pod system - no complaints there. 

So, I find it interesting that there may be an issue beyond this new modem….

I’ll follow your advice & check the entire system start to finish over the weekend.  Then I’ll reach out to Xfinity next week & request they do the same.  

Thanks again for your time & help!!

Xfinity does know you have what amounts to two modems on the line, correct? Those need separate IP addresses. It’s not that common that folks set things up that way and it will also be important to confirm they have both provisioned correctly. Sounds like you are on the right track. Hope it all works out well for you!

All lines & connections checked twice - everything is connected securely - so no problem there.

I explained my intentions to Xfinity  prior to purchasing this modem, to make sure the setup would work.  Per Xfinity  - all I needed to do was activate the new device through their app, which I did.  Following activation, their app indicated all was well in the world. 

But, I think you’re right.  I think I need to call Xfinity to make sure they have things set up correctly on their end before throwing in the towel.

Keep you posted.

Thanks!!

I really appreciate the time you’ve invested in working toward a solution to my situation.

But…  I’m ready to throw in the towel on this Surfboard.  

My Xfinity plan is 1,000 mbps, getting close to 1,200 mbps through the system.  I’m in Chattanooga, TN, aka “Gig City”, so Xfinity has to offer up big numbers to remain competitive with EPB.

Xfinity did their thing yesterday, but it didn’t help.  Xfinity said things checked out fine on their end & that the modem should be working.  But, no dice…

I give up…

Returning the Surfboard from whence it came.

Thanks Again!