1113361's profile

Contributor

 • 

28 Messages

Sat, Dec 26, 2020 7:00 PM

Connectivity Issues with 3rd party modem (Netgear CM1150V) - Comcast Tech Request Please

 

History of my issue

CM1150V on Xfinity 600Mbps plan

Worked perfectly for almost a year - consistent full spec speeds 

Around mid Nov, began to have frequent drop-outs and occasionally throughout day but EVERY morning would have to power cycle modem to re-establish connection 

After dealing with that EVERY DAY for about 2 weeks, called out Xfinity. 

Xfinity Tech checked lines all way to street interface - no issues, installed Xfinity XB7 and all was perfect (immediate and consistent thereafter); 

Felt confident this was a hardware issue as it appeared the XB7 resolved the issue i.e. it worked consistently, the CM1150V did not. 

 

Received replacement CM1150V 12 days ago and re-commissioned with Xfinity

Initially worked perfectly and consistently for 10 days then suddenly 2 days ago began having identical issues to first one 

(this makes me wonder if in both instances a firmware 'upgrade' was pushed by Xfinity?) 

(have since learned this is the std firmware at this time, so I don't believe that to be the case- I can also see that my signal levels are now higher than they were a couple of weeks ago) 

 

Here is log from the last 12 hrs or so - note that this was while the Modem was essentially unused during the night! 

Came down this morning to find no internet connection and attached is the Event log showing the period of preceding 12 hrs or so 

6:44am is when I power cycled the Modem, so those errors pertain to that. 

(after power cycling the modem it came back on line at full download and upload spec speeds - this behaviour is consistent with that of the initial modem after a power cycle) 

 

I have included images of the Event Error Log, the Baseline Modem Status when it was working perfectly when installed on 12-15 and the Modem Status yesterday (when there was no Internet Connection) 

 

https://www.dropbox.com/s/jxyb8f5ki265951/Xfinity_CM1150V_Screenshots.pdf?dl=0

 
 

Only differences I see in the Modem Status are: 

The Download Frequencies are much higher generally in the baseline 

There is a high incidence of 'correctables' in the problem status of yesterday 

 

Other interesting notables

When a Download has been established and continuous (e.g. such as streaming a movie or live sports through my subscriptions) it tends to remain consistent until there is a break in download traffic (once it has been idle, it will not re-establish a connection) 

Another way to recover the connection besides the Power Cycle of the modem is just to keep requesting a Speed Test (I use the Ookla App downloaded on my devices)  - this one is curious - I can request multiple times and it fails, then finally it will connect with very slow download speed (only a few Mbps) initially and then the upload part of the test is at full spec (18Mbps); the very next speed test (run immediately after) will deliver full speed down and up. 

A modem power cycle will immediately re-establish full spec speed once reboot completes. 

The behaviour is now identical on second modem as was the original 

Both Modems were performing perfectly & consistently before suddenly becoming consistently problematic (again this makes me suspect a firmware upgrade?) 

But almost certainly rules out Hardware 

The XB7 had zero issues during its 3 weeks installation (and problem was consistent with initial CM1150V prior to the XB7 install which instantly resolved it)  

 

What does the log indicate was going on during that night time (supposedly idle) period? 

 

- can you take a look at this?  

 

@ComcastChe

Responses

EG

Expert

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87.2K Messages

6 m ago

Can't see those pics. Do what you did before with copying and pasting the text.

1113361

Contributor

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28 Messages

6 m ago

Sure (hopefully not as regards a truck event) 

But regardless they are simply illustration of what of I've described - just that per the app it thinks Modem is offline, nothing more than that. 

1113361

Contributor

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28 Messages

6 m ago

Pics will likely show up tomorrow when they're approved

Those pics are simply screenshots from my Xfinity apps on my phone - they just both show that the modem is offline at least as far as the Mother Ship believes (even though at that time it was functioning and allowing internet access/data exhange);

so along with me having trouble my end, it appears that Xfinity Central is not getting the appropriate communication with my modem. 

 

Shortly after my post showing success for the day, by 7pm or so back to the same issues again with Internet coming and going, then losing lock and requiring power cycle. So got just shy of about 12 hours of good performance. 

EG

Expert

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87.2K Messages

6 m ago

There is no guarantee that they will show up by tomorrow....

 

I may be run over by a truck tomorrow...

EG

Expert

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87.2K Messages

6 m ago

The modem is missing a bunch of downstream channels. Seems that there is a signal / connection quality impairment between the modem and the Comcast system. Comcast Rob offered assistance earlier in the thread. You should work with him, and / or get a tech out to investigate this one.

 

Good luck with it !

ComcastChe

Official Employee

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6.1K Messages

6 m ago

Hi @1113361! We'd be happy to assist you! If you haven't already, can you please send me or @ComcastRob a private message so we can gather your account details?  To send a private message, click on one of our names and then click send a message. 

1113361

Contributor

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28 Messages

6 m ago

Thanks @ComcastChe - I will send the details as per mail to @ComcastRob yesterday (not sure if he has been active since then) 

1113361

Contributor

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28 Messages

6 m ago

The line guys came out today after I got in touch with the Technical Operations Supervisor for my area 

They made some changes is the box over on the Main Road running parallel to my street

(my modem lost signal and I thought, oh boy here we go again - when my wife mentioned she could see Xfinity truck over on the Main Road) 

Then when the modem re-booted I could see immediately that the power levels had improved significantly 

(this is still without the splitter connected, but you can see relative to the numbers posted earlier) 

 

 
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
 

Startup Procedure

ProcedureStatusComment
Acquire Downstream Channel555000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
SecurityEnabledBPI+
IP Provisioning ModeHonor MDDhonorMdd(4)
 

Downstream Bonded Channels

ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25628555000000 Hz8.3 dBmV42.5 dB00
2LockedQAM25617483000000 Hz7.5 dBmV42.3 dB00
3LockedQAM25618489000000 Hz7.6 dBmV42.3 dB00
4LockedQAM25619495000000 Hz7.8 dBmV42.3 dB00
5LockedQAM25620507000000 Hz8.1 dBmV42.4 dB00
6LockedQAM25621513000000 Hz8.2 dBmV42.4 dB00
7LockedQAM25622519000000 Hz8.2 dBmV42.4 dB00
8LockedQAM25623525000000 Hz8.1 dBmV42.4 dB00
9LockedQAM25624531000000 Hz8.1 dBmV42.4 dB00
10LockedQAM25625537000000 Hz8.1 dBmV42.4 dB00
11LockedQAM25626543000000 Hz8.2 dBmV42.5 dB00
12LockedQAM25627549000000 Hz8.1 dBmV42.5 dB00
13LockedQAM25629561000000 Hz8.4 dBmV42.5 dB00
14LockedQAM25630567000000 Hz8.2 dBmV42.4 dB00
15LockedQAM25631573000000 Hz8.5 dBmV42.4 dB00
16LockedQAM25632579000000 Hz8.8 dBmV42.6 dB00
17LockedQAM25633585000000 Hz8.6 dBmV42.5 dB00
18LockedQAM25634591000000 Hz8.8 dBmV42.6 dB00
19LockedQAM25635597000000 Hz8.7 dBmV42.4 dB00
20LockedQAM25636603000000 Hz8.4 dBmV42.3 dB00
21LockedQAM25637609000000 Hz8.5 dBmV42.3 dB00
22LockedQAM25638615000000 Hz8.3 dBmV42.3 dB00
23LockedQAM25639621000000 Hz8.2 dBmV42.3 dB00
24LockedQAM25640627000000 Hz8.3 dBmV42.3 dB00
25LockedQAM25641633000000 Hz8 dBmV42.2 dB00
26LockedQAM25642639000000 Hz7.8 dBmV42.1 dB00
27LockedQAM25643645000000 Hz8.1 dBmV42.3 dB00
28LockedQAM25644651000000 Hz7.8 dBmV42 dB00
29LockedQAM25645657000000 Hz7.7 dBmV42.1 dB00
30LockedQAM25646663000000 Hz7.9 dBmV42.1 dB00
31LockedQAM25647669000000 Hz7.4 dBmV42 dB00
32Not LockedUnknown00 Hz0.0 dBmV0.0 dB00
 

Upstream Bonded Channels

ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA15120 Ksym/sec17300000 Hz45 dBmV
2LockedATDMA25120 Ksym/sec23700000 Hz45 dBmV
3LockedATDMA35120 Ksym/sec30300000 Hz44.5 dBmV
4LockedATDMA45120 Ksym/sec36700000 Hz44.3 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
 

Downstream OFDM Channels

ChannelLock
Status
Modulation /
Profile ID
Channel
ID
FrequencyPowerSNR /
MER
Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1Locked0 ,1 ,2 ,348688000000 Hz7.3 dBmV41.4 dB1108 ~ 29871631721499400
2Not Locked000 Hz0 dBmV0.0 dB0 ~ 4095000
 

Upstream OFDMA Channels

ChannelLock StatusModulation / Profile IDChannel IDFrequencyPower
1Not Locked000 Hz0 dBmV
2Not Locked000 Hz0 dBmV
 

Current System Time:Thu Jan 07 13:44:37 2021System Up Time:00:01:15

It's only been a couple of hours - time will tell - so far so good. 

I'm at least encouraged by the power level being down 

 

Right now I'm leaving the splitter out of equation and still connected directly to the modem only 

If I get a solid 24hrs, I'll hook the splitter back up and see how that works. 

 

The oddity of the Xfinity App not seeing my modem however remains - the line tech said he could not see my modem either (he mentioned this unprompted) 

And further, I cannot connect to my Xfinity App via my home network connection ONLY via 4G; 

so I turn off Wifi on my phone and it connects to the App - then I can turn wifi back on and move around the app. I deleted and re-installed the App and it still exhibits this behaviour 

And again, once in the App - whether connected by 4G OR my Local Network it still shows my modem Offline. 

Gambit66

Problem Solver

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316 Messages

6 m ago

@1113361  Can you not login to the comcast modem instead of using the app to see exactly how it`s set up?

Gambit66

Problem Solver

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316 Messages

6 m ago

@1113361  oh You are using our own personal modem instead of comcasts modem?

@1113361  I don`t believe the Xfi app works with using your own equipment, just comcast modems.

1113361

Contributor

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28 Messages

6 m ago

@Gambit66 - the Comcast modem is not activated - I could re-connect it and read the power levels but I don't think that will do anything for seeing it via the app, without activation (or would it???) 

Regardless - it doesn't really resolve issue of why the Xfinity Network is not seeing my Netgear modem. 

1113361

Contributor

 • 

28 Messages

6 m ago


@1113361 wrote:

The line guys came out today after I got in touch with the Technical Operations Supervisor for my area 

They made some changes in the box over on the Main Road running parallel to my street

Then when the modem re-booted I could see immediately that the power levels had improved significantly 

 Came down this morning - so refreshing to see my LAN devices were online, all the LEDS on the modem on solid (not in bootloop!) and instant full-speed download! 

And checking the modem event log showed zero errors overnight either! 

 

Haven't installed splitter yet, but confident - things are much, much better 👍 👍

EG

Expert

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87.2K Messages

6 m ago

You should be able to get away with a 2-way splitter, or an unbalanced 3-way using the 3.5 dB tap (if the connection stays stable), but a balanced 3-way or anything larger will push the upstream power up in to the danger zone again. Good luck !

1113361

Contributor

 • 

28 Messages

6 m ago

I'm probably justgoing to do a quick test to see if it indeed works on the 3.5dB split just to see how much headroom there is - however my plan is to eliminate the Triple Play Package and just have the Xfinity Internet - never use the home phone and it's all the add-ons with the TV package that are onerous, even with a minimal package; fees for equipment rental, DVR service etc are all just ridiculous. 

Gambit66

Problem Solver

 • 

316 Messages

6 m ago


@1113361 wrote:

I'm probably justgoing to do a quick test to see if it indeed works on the 3.5dB split just to see how much headroom there is - however my plan is to eliminate the Triple Play Package and just have the Xfinity Internet - never use the home phone and it's all the add-ons with the TV package that are onerous, even with a minimal package; fees for equipment rental, DVR service etc are all just ridiculous. 


You could ask them to run a seperate line from the pole just for the TV/DVR. They usually have several open. I had ours done that way by the suggetion of the comcast installer years ago.

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