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Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

Vinsk1969
Aspirant

cm1000 and xfinity issues or just Docsis 3.1 issue?

Hello all. I upgraded to the Gigabit plan with Xfinity. I use my own Modem (Arris Surfboard 3.0). After realizing I needed a Docsis 3.1 I bought the Motorola MB8600 or whatever but it was 3.1. Comcast couldn’t get it to keep a signal. The modem kept rebooting over and over. Comcast tech came to my house and said I had a defective modem as his test modem (3.0) worked fine. So he left me the Netgear (unknown model but 3.0) to use until I replaced my ‘defective’ modem. I then bought The Netgear CM1000 (and the triple band Nighthawk AC..whatever router.) Sorry I cant recall the model but I don’t think it relates to the problem.
So I hook up the CM1000. Wall coax to modem, Ethernet cable to desktop (ibuypower gaming system with Windows 10). Lo and behold the same problem happened. The modem is rebooting over and over just as the Motorola did. I seriously doubt I bought 2 defective modems back to back. The modem does this with or without the router connected. So now Comcast is sending out a tech on Monday but I fear he/she will not be able to fix this as the tech from yesterday was apparently wrong. Any ideas as to why this is happening? Why do Docsis 3.0 modems work fine but 3.1 seem to not work? I’m not real tech savvy so apologize if my post seems comical..lol. Any ideas?
Model: CM1000|DOCSIS® 3.1
Message 1 of 12
Maeredyth
Aspirant

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

I apologize I came here looking for answers myself and I am not  extremely the tech savy type so I cannot help you with your question other than to say that from my experience with Xfinity, they will send a guy out, charge you $50 for him coming and he won't fix the issue but will be glad to rent you one of their modems for $10 a month forever and magically it will work fine right out of the box.  Does Netgear not take phone calls at all while you are in warranty period so they can help folks in your situation?

Message 2 of 12
Vinsk1969
Aspirant

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

So get this: After having the second tech come out he walks in and says, “ your condo unit isn’t set up with Fiber Optic cable so that’s why you can’t connect. Gigabit plan isn’t even an option for you.” LOL! This, after I’ve paid a month of Gigabit plan which never worked. He says the ‘sales people’ don’t really know that information. So I’m sure both the Netgear and Motorola modems were just fine. So I’m back with Netgear modem with the Blast 150. That’s the best I can get. Solved.
Message 3 of 12
MattN
Tutor

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

I am having the same set of issues with Comcast in Seattle area.  Anyone know what I can do to debug why the CM1000 is so spotty?   Every few days I lose all connectivity and have to reboot the modem.   Downloaded latest patches.   With previous modem the thing would work for months no issues.   My wife is saying I paid out the nose for CM1000 and the thing is much worse than the 30$ Motorola we used in the past.   Can't really argue with her.

 

To debug I wrote a program to periodically connect ever 15 seconds to a remote site and verify connectivity.   Sure enough about every 1-2 days I lose all connectivity and it does not recover.   Have to cold boot modem.   The logging on the modem looks pretty shoddy, how can I debug this thing?

Model: CM1000|DOCSIS® 3.1
Message 4 of 12
MattN
Tutor

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

Please reply with some specific things I can do to debug the CM1000.   The logs are pretty weak.

Message 5 of 12
Maeredyth
Aspirant

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

Mine is only dropping about once  every week or two, but I still think that's too often.  Otherwise it's fast and I like it.  Now that I figured out how to to disable the house alarm from waking me up in the middle of the night when it drops signal I am slightly less annoyed.  It is stil a pain to discover as I am trying to leave for work I have to stop and go upstairs and make time to reboot it before I can set the alarm and leave for work, but still better than being awaked at  3 am by the alarm signaling it lost connectivity.

 

Personally, I think it's related to Comcast and all of the changes they have been making to the streaming portal since they are being sued by the people that bought Tivo for patent infringment.  My modem worked fine  and I had no trouble until after Thanksgiving when comcast disabled features in their streaming portal causing customers like me to call them four times a week about features they broke by accident in the process of hastily trying to comply with the court order to remove specific features.  As they then tried to do damage control, and restore the ones they broke by accident, everytime their programmers made a change, they had to push those updates to each user and I think while thye were doing all that my problem was way worse.  It seems to have gotten significantly better for me in the past month now that they have restored most o fthe collateral damage

Message 6 of 12
DarrenM
NETGEAR Moderator

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

Are you able to post the power levels of your connection? 

 

DarrenM

Message 7 of 12
Maeredyth
Aspirant

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency

<tabindex=-1>Startup Procedure

ProcedureStatusComment
Acquire Downstream Channel609000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
Configuration FileOK------------
SecurityEnableBPI+

<tabindex=-1>Downstream Bonded Channels

ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25621609000000 Hz5.9 dBmV40.1 dB00
2LockedQAM2561489000000 Hz7.5 dBmV41.1 dB00
3LockedQAM2562495000000 Hz7.4 dBmV41.0 dB00
4LockedQAM2563501000000 Hz7.3 dBmV40.9 dB00
5LockedQAM2564507000000 Hz7.5 dBmV37.8 dB00
6LockedQAM2565513000000 Hz7.3 dBmV41.0 dB00
7LockedQAM2566519000000 Hz7.3 dBmV40.9 dB00
8LockedQAM2567525000000 Hz7.3 dBmV40.8 dB00
9LockedQAM2568531000000 Hz7.2 dBmV40.8 dB00
10LockedQAM2569537000000 Hz7.2 dBmV40.7 dB00
11LockedQAM25610543000000 Hz7.1 dBmV40.6 dB00
12LockedQAM25611549000000 Hz6.9 dBmV40.4 dB00
13LockedQAM25612555000000 Hz7.1 dBmV40.6 dB00
14LockedQAM25613561000000 Hz7.0 dBmV40.2 dB00
15LockedQAM25614567000000 Hz6.8 dBmV40.3 dB00
16LockedQAM25615573000000 Hz6.9 dBmV40.3 dB00
17LockedQAM25616579000000 Hz6.5 dBmV40.8 dB00
18LockedQAM25617585000000 Hz6.2 dBmV40.8 dB00
19LockedQAM25618591000000 Hz6.0 dBmV40.3 dB00
20LockedQAM25619597000000 Hz5.9 dBmV40.3 dB00
21LockedQAM25620603000000 Hz5.9 dBmV40.3 dB00
22LockedQAM25622615000000 Hz5.6 dBmV39.9 dB00
23LockedQAM25623621000000 Hz5.5 dBmV39.9 dB00
24LockedQAM25624627000000 Hz5.1 dBmV39.4 dB00

<tabindex=-1>Upstream Bonded Channels

ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA15120 Ksym/sec36100000 Hz43.3 dBmV
2LockedATDMA25120 Ksym/sec29600000 Hz43.5 dBmV
3LockedATDMA35120 Ksym/sec23000000 Hz43.5 dBmV
4LockedATDMA45120 Ksym/sec16500000 Hz43.5 dBmV
5Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
6Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
7Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
8Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV

Current System Time: Tue Apr 03 20:06:58 2018 

Message 8 of 12
MattN
Tutor

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

Note here are my stats, look pretty good:

 

Cable Connection

Apply Cancel
Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency
639000000
Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 639000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enable BPI+
IP Provisioning Mode Honor MDD IPv6 only
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR / MER Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked QAM256 25 639000000 Hz -1.0 dBmV 38.0 dB 224514965 97 0
2 Locked QAM256 1 483000000 Hz -1.0 dBmV 38.8 dB 221670518 6 0
3 Locked QAM256 2 489000000 Hz -0.7 dBmV 38.8 dB 221684214 1 0
4 Locked QAM256 3 495000000 Hz 0.0 dBmV 38.8 dB 221697351 2 0
5 Locked QAM256 4 507000000 Hz -1.7 dBmV 38.5 dB 221709990 2 0
6 Locked QAM256 5 513000000 Hz -3.3 dBmV 38.4 dB 221722831 3 0
7 Locked QAM256 6 519000000 Hz -3.3 dBmV 38.4 dB 221735725 8 0
8 Locked QAM256 7 525000000 Hz -2.2 dBmV 38.5 dB 221749433 5 0
9 Locked QAM256 8 531000000 Hz -1.8 dBmV 38.5 dB 221762336 10 0
10 Locked QAM256 9 543000000 Hz -2.0 dBmV 38.4 dB 221775443 8 0
11 Locked QAM256 10 549000000 Hz -2.9 dBmV 38.2 dB 221788520 8 0
12 Locked QAM256 11 555000000 Hz -3.0 dBmV 38.1 dB 221801376 18 0
13 Locked QAM256 12 561000000 Hz -2.5 dBmV 38.2 dB 221822634 20 0
14 Locked QAM256 13 567000000 Hz -2.2 dBmV 38.2 dB 221836130 17 0
15 Locked QAM256 14 573000000 Hz -1.9 dBmV 38.3 dB 221848501 25 0
16 Locked QAM256 15 579000000 Hz -2.1 dBmV 38.2 dB 221862091 28 0
17 Locked QAM256 16 585000000 Hz -2.0 dBmV 38.2 dB 221875431 27 0
18 Locked QAM256 17 591000000 Hz -1.9 dBmV 38.1 dB 221888649 24 0
19 Locked QAM256 18 597000000 Hz -1.5 dBmV 38.0 dB 221901593 44 0
20 Locked QAM256 19 603000000 Hz -1.2 dBmV 38.1 dB 221914425 37 0
21 Locked QAM256 20 609000000 Hz -1.1 dBmV 38.1 dB 221927939 54 0
22 Locked QAM256 21 615000000 Hz -1.1 dBmV 38.0 dB 221941485 57 0
23 Locked QAM256 22 621000000 Hz -1.3 dBmV 38.2 dB 221954893 46 0
24 Locked QAM256 23 627000000 Hz -1.5 dBmV 38.0 dB 221967464 80 0
25 Locked QAM256 24 633000000 Hz -1.2 dBmV 37.8 dB 221980886 71 0
26 Locked QAM256 26 645000000 Hz -1.0 dBmV 37.7 dB 221993619 79 0
27 Locked QAM256 27 651000000 Hz -1.2 dBmV 37.7 dB 222007106 111 0
28 Locked QAM256 28 657000000 Hz -1.5 dBmV 37.8 dB 222020222 81 0
29 Locked QAM256 29 663000000 Hz -1.4 dBmV 37.6 dB 222031542 87 0
30 Locked QAM256 30 669000000 Hz -1.2 dBmV 37.7 dB 222039345 75 0
31 Locked QAM256 31 675000000 Hz -1.3 dBmV 37.3 dB 222046242 86 0
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0

Upstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power
1 Locked ATDMA 1 30100000 Hz 63.3 dBmV
2 Not Locked Unknown 0 0 Hz 0.0 dBmV
3 Not Locked Unknown 0 0 Hz 0.0 dBmV
4 Not Locked Unknown 0 0 Hz 0.0 dBmV
5 Not Locked Unknown 0 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Hz 0.0 dBmV
Downstream OFDM Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier Number Range Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked 0 159 745000000 Hz -0.8 dBmV 36.8 dB 1126 ~ 2969 188572963 0 0
2 Not Locked 0 0 0 Hz -4.3 dBmV 0.0 dB 0 ~ 4095 0 0 0
Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked Unknown 0 0 Hz 0 dBmV
2 Not Locked Unknown 0 0 Hz 0 dBmV
Current System Time: Tue Apr 03 18:44:45 2018

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Model: CM1000|DOCSIS® 3.1
Message 9 of 12
DarrenM
NETGEAR Moderator

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

All the levels look fine. Do you get any T3 or T4 timeouts in the logs?

 

DarrenM

Message 10 of 12
MattN
Tutor

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

Yes, lots of T3 timeouts.

 

 

Bought brand new Motorola MB8600, same spotty connectivity issues.  Same T3 timeouts in log.  Working to get Comcast out to my house to investigate.   Comcast tech claimed to have "boosted" the signal of my modem via some  mystical remote software patch of my modem.  Still same problem.

Model: CM1000|DOCSIS® 3.1
Message 11 of 12
MattN
Tutor

Re: cm1000 and xfinity issues or just Docsis 3.1 issue?

Just a follow up.  Comcast came out and replaced my outdoor splitter and signal now is great and modem rock solid.    So root cause was poor signal due to faulty old splitter.

Model: CM1000|DOCSIS® 3.1
Message 12 of 12
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