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Docsis 3.1, $180 'compatible' modems, witchcraft, apathy, and Xfinity Internet service

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Re: Docsis 3.1, $180 'compatible' modems, witchcraft, apathy, and Xfinity Internet service

Hi @tfulkerson -- How did the tech visit go?

I am not a Comcast employee, just a moderator. Pls observe Wheaton's Law.
Regular Visitor

Docsis 3.1, $180 'compatible' modems, witchcraft, apathy, and Xfinity Internet service

1. Get email from xfinity telling me l need to upgrade my modem. My service was working well at the time, but I took the opportunity to get rid of Xfinity's lame hybrid (gross) and get better speed from my connection.
2. Buy Arris SB8200. (and be a little surprised at how small it is)
3. Return xfinity rental. (good riddance, so I thought... )
4. Unable to provision router (SW failed before download - Server not Present). Can't get to the walled garden, can't get comms with the dns or dhcp. Sigh dejectedly (I think that isn't a word, but whatevs).
5. Call and do chat support with xfinity on 6 different occasions throughout the evening without success. Steps taken: reboot modem, factory reset modem, restart computer, swap out cables, reboot modem and computer in specific order, reboot modem and computer and attach cables in a specific order, try different outlet, listen to rep say they pushed some sort of magic button and tell me my problem is fixed, rub belly and pat head at the same time, perform ritual sacrifice, call Arris who told me it's Xfinity's provision, netsh winsock reset, netsh in ip reset, restart everything again, factory reset modem again, ipconfig /flushdns, ipconfig /release, ipconfig /release 6, ipconfig /renew, ipconfig /renew 6, ipconfig /registerdns, restart everything again, call xfinity and speak with sympathetic "tech support" who did more magic button pushing with no success. I also wanted to say that all the reps were extremely courteous and seemed like they did what they knew how to and felt bad they couldn't make it work. So the interaction with them was great. Just not the process. Which seemed scripted and useless.
6. Buy Netgear CM1000 to replace Arris 8200. Ugh ($360 of modems).
7. Can't provision Netgear (SW upgrade failed before download server not Present).
8. Rage eat ice cream.
9. Put my full name, address, phone number, account number, last four social security into my phone dictionary so I don't have to type it all out every time I chat. Die a little bit every time I call support.
10. Repeat steps 4 and 5 again.
11. Go get new rental from xfinity.
12. Xfinity rental won't provision.
13. Repeat steps 4 and 5 again.
14. Reluctantly accept a tech visit to come fix a problem that didn't exist until I tried using non-xfinity hardware. Cue conspiracy theory about internet providers causing the apocalypse.
I put the CM1000 back on because it seems to have the most complete logging I can access.
If I could get online, I'd gladly post my comm stats and logs. So I'm just going to type out what I think is relevant based on what I've read here in the forums on the same exact problem that has been happening since 2016 (or older) and doesn't have a clear resolution because the problem returns shortly after the tech visit ends.

Acquire downstream 639000000 Hz
Connectivity OK Operational
Boot same
IP provision mode honor mdd ipv6 only

Downstream bonded QAM256
Channel 1 (id25) 639000000 hz -21.7 dBmV booooo.
Channels 2 through 18 between 7 and 10 dBmV
The rest between 10 and 20 dBmV
Signal noise between 30 and 40.1 dB
Upstream bonded ATDMA
All four between 47 and 48 dBmV
Nothing in OFDM or OFDMA channels

System logs
Starting Unicast Maintenance Ranging no response t3 time out
3x of
Sync timing failure - failed to acquire qam/qpsk
Honoring mdd ip provision mode ipv6
SW download in it via config file
SW upgrade failed before download server not Present
Unicast DSID PSN startup error

and then it taunts me while I torture myself with tech support.
So obviously I want to fix this. I realize some of the numbers are 'out of spec' and some are in spec. Amusingly enough, nobody in any of my calls or chat sessions could tell me what these specs were and greeted me with dumbfounded silence when I told them the downstream numbers. And I think that they literally put the phone down for a bit when I asked about the log entries.

I do have a tech appointment Monday afternoon. But I fear that like many before me, will maybe get some new cable or filters removed or added, but won't be able to provision the modem. And by some dark magic, they'll be able to get their rental working. Ugh.

So I'm taking all suggestions, ideas, wizardry, blood contracts, vows of (?) if it leads to good internet service using my own modem (and my own router which has been sadly neglected because of Xfinity's unwillingness to turn off dhcp in their router and left double NAT which every 23 hours, booted me off the internet but also felt undervalued as an access point).

Thanks for reading. Smiley Happy