Orbi WiFi 7 RBE973
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Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Santa_Cruzer
Guide

CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Hi,

I found this forum somewhat helpful and and going to post my experience troubleshooting a problem with the CM1150V.  I have not found root cause, but seem to have resolved it for now swapping out another brand of modem.  I'm wondering if others have similar problems.

 

About 9 months ago, I updgraded service to 600 Mbit/s finity service, bought a docsis 3.1 CM1150V recommended from Xfinity.   Worked great, no issues.  Come mid-December, my Sonos streaming radio starts dropping out, restarting, sometimes just stopping altogether for 20 minutes.  Concurrently, started to have other connectivity issues on video conference calls, modem getting stuck and needing reboot, going offline for minutes at a time.  Sometimes, no service for 20 minutes.  At first, I thought they were performiing line maintainance.  Except it continued and the dropouts got worse.  My morning radio streaming couldn't stay online past 5 minutes at a time, the Roku streaming video (directly wired) actually was almost fine for the most part, except for a few minor annoying short drops every evening, it's buffers seem to handle better than the Sonos radio streaming.

 

I have the Orbi's RBR50's for Wifi, it does a speed test, no issues - plenty of downstream speed.  I did notice upstream was getting a little faster over the months, from about 9 mbit/s to about 14 ms/sec now, interestlingly, my download speeds seem to degrade some from 450 Mb/sec earlier in December to about 300 Mb/sec now (Dec-22).  I'm familiar with the upstream power issue from a few years ago, troubleshooting a bad coax - and the colder temperatures seem to precipitate these problems.  While all my down/upstream power readings were well in spec, I did notice numerous T3 ranging requests were logged - one every few minutes, I then went on a campaign to simplify the connectivity and try several other cable paths in the house, inlcuding a direct hookup to outside box.  It was a waste of time - the modem would spend a random time period to reconnect - sometimes 2 minutes, sometimes 20 minutes - no matter how I hooked it up.  I did lots of online searching to see what the problem might be to no avail.  I do believe it has something to do witht his upstream channels, even though I have no big speed problems, plenty of bandwidth overall - my problems are the modem going offline for anywhere from 2 to 20 minutes at a time and frequently. 

 

I did find an odd reading on the upstream channels, only one upstream channel seemed to lock and it was the lowest frequency, 17.3 MHz at 44.5 dBmV power (power seems inline) and showed "partial service" status.    I reasoned it might have something to do with my problem, I saw so many other postings here with multiple channels locked, and many of my T3 errors would refer to a second channel that seemed to not show being locked.

 

I wasn't clear on the root cause, it could be the modem HW going bad (I've had a few go bad in the last 20 years) or could be a firmware update - my modem was running v4.02.02 - or combination of both, or the IS provider did something, or perhaps a noisy neighbor line, or some combination.   It's hard to diagnose since telecommnications are so interdependent, but I do know the long and often variable 20 minutes to reconnect wasn't normal and didn't seem to matter how I hooked it up with various simplified wiring.

 

I decided to swap out and try an Arris T25 modem, it has similar specs, but different chipsets and firmware altogether.  If this doesn't work, then I reasoned I have a good case for the IS provider to check their end.

 

The T25 came up quickly, good and quick self-service provisioning provided by Xfinity/Comcast (I said something nice about them 🙂 ).  First thing I noticed is now I have multiple upstream channels, and on the highest 2 frequencies 36.7 MHz and 41.2 MHz at 42.75 dBmV and 45.75 dBmV respectively.  The T3 errors still continued at the same rate, so I wasn't sure if it made a difference at first.

 

After 24 hours, I've not had any offline events - clearly a signficant difference.  Upstream data rates are now over 18 Mb/sec, I think the IS has been improving this capability since it's a competitive disadvantage to fiber optic, perhaps my CM1150V might have started struggling, triggering offline events and long reconnects when they started to updgrade capability.

 

I'm not sure what to do with the CM1150v - it might be fine, perhaps roll back the firmware might make a difference if possible and sustainable.  HW could have degraded over time, or could have remained the same and IS started to upgrade the lines to faster speeds, sent out updated firmware, and created a problem for my modem.  I really don't know.  I thought I'd post here to see if anyone knows more definitely what's going on, aside from a faulty modem which is my default belief - either from the beginning and became a casualty over line and FM upgrades, or simply degraded over time.  I'd be willing to roll back FW and re-provision if there was an explanation to indicate a reasonable chance of prolonged success, then I could return the T25 and continue with the CM1150V.

 

However, connectivity these days is important to myself and wife for work, so having a spare modem of different chipset/firmware ready to go seems wise, albeit a little costly upfront.  I am aware of the troubles written of the T25 Intel chip, but so far, no issues here and these seem minor to my troubles.  I'd really rather know what's gone wrong so in the future, I can better address issues like this.

 

Another note:  I seem to always have trouble when it gets cold outside, I believe the upstream capabilities are the most challenging technically, and stress the modem capabilities the most.  At least that seems to correlate to my problems.  I've had overpowered upstream ampilification that results in modem overheating and resetting (a problem I had years ago on a prior modem, bad cheap in-house coax was the blame pushing upstream power to over 50 dBmV) that only happened when it got below freezing temperatures here - a result of the line resistance dropping.  Recently, similar situation, except it's not a power issue, but rather a channel spectral response change to go from barely acceptable performance to unacceptable in the frequency domain as a result of resistance drop due to colder temps, and my marginal setup and configuration is vulnerable.  I'd be curious to know if xfinity/comcast service calls uptick when the temperatures drops outside each season.

 

Attached are status screenshot on CM1150V and new Arris T25 screenshot below it.  Note upstream channels status in each case.  Numbers are consitent after restiing, except upstream power creeps up a bit over time (e.g. 39 dBmV to 44 dBmV ) but stays in spec.  Note each vendor may have different ways to measure the same thing, so I wouldn't get too hung up on dBmV and power level comparisons as long as they are in spec.  The upstream channels - the number and frequency -  seem to stand out.

CM1150V status screenshot 1CM1150V status screenshot 1CM1150V status screenshot 2CM1150V status screenshot 2CM1150V status screenshot 3 with Upstream "Partial Service" indicatedCM1150V status screenshot 3 with Upstream "Partial Service" indicatedArris T25 status screenshot 1Arris T25 status screenshot 1Arris T25 status screenshot 2 - note change in # of upstream channels and frequencies.Arris T25 status screenshot 2 - note change in # of upstream channels and frequencies.

 

Model: CM1150V|DOCSIS 3.1 Nighthawk® Multi-Gig Speed Cable Modem for XFINITY® Voice
Message 1 of 27
FURRYe38
Guru

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 
Be sure to power OFF the modem for 1 minute them back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...

 

What Firmware version is currently loaded on Orbi?

Message 2 of 27
Santa_Cruzer
Guide

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

 

Thanks for your response, I'm aware of all the standard troubleshooting.


When wired directly with no splitters, it made no difference - it would disconnect often and take up to 20 Minutes or more to reconnect.  In fact, it almost seemed worse, going beyond 20 minutes to try and establish a connection.  It was provisioned 9 months ago when installed and has worked well up until recently,  Does re-provisioning make any differences that might resolve this situation?


 I don't understand why having ISP check signal on my line (coming out and measure) when another modem seems to work fine without disconnects for 2 days now?  That would seem to isolate the problem to my cm1150v modem.  

 

ISP said my cm1150v modem is working fine from their end with their online status check, although I suspect this health diagnosis is quite rudimentary.

 

Always good to have tech come and measure line quality, I could probably force them to do it, that usually takes some time.  With a T25 working fine, with seemingly healthier upstream status, I'm having a hard time justifying a tech visit to save the CM1150v that has gone bad, or was bad from the beginning and recent operating conditions moved it to operate marginally.

 

If I had a rational explanation why the CM1150v might still be good, I might go through that trouble.


I don't understand your question on Orbi firmware version.   the Orbis continue to run fine on my home network when cm1150v modem disconnects often from ISP.   They work really good, best signal I've ever had here by far.  Are there known firmware issues here that could result in modem connection to ISP frequently dropping?  If so, maybe you could bring to light?  

 

 

Message 3 of 27
FURRYe38
Guru

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

If a different modem works and seems to resolve the problem, then possible the CM modem could be faulty. Something to contact NG support about. 

 

There are some versions of Orbi FW that cause problems. There is a reason for asking about FW version. 

Message 4 of 27
Santa_Cruzer
Guide

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Thanks for your reply.

I may take up with NG as the burden will be on them now and may still be under warranty.  I'll leave it here for others in case they run into similar issues.

 

I'd rather avoid disclosing too much about my network hardware and software.  I already have logged a few "visitors" from time to time, showing up trying to crack usernames and passwords.

Message 5 of 27
FURRYe38
Guru

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

For troubleshooting and helping users out. It's ok to give FW versions. It helps us help you.

 

Good Luck. 

Message 6 of 27
Santa_Cruzer
Guide

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Since it's been over 90 days since purchase, Netgear wants me to sign up for a service plan before they will let one of the techs work with me.  Plan is refundable if they find their hardware at fault and will replace it under warranty.

So, this is gambling.  I told the representative I thought they'd value knowing about a problem I isolated and want to study it.  I suppose they get lots of calls about poor internet and it's not their fault in the end, so they need a barrier.

 

I decided to think about it.  I may do a factory reset, provision again, and see if it recovers those upstream frequencies and/or holds the link.  The "gambling odds" might improve with a few more hours invested if it keeps performing poorly..  Maybe when I get bored over the holidays....

 

 

Message 7 of 27
FURRYe38
Guru

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Does your modem have a option that mentions Higher Power on the Connections page? 

 

Message 8 of 27
FURRYe38
Guru

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

"Extended Upstream Transmit Power"

 

Also your modems Power and SNR should be around these values: What i have on my CM1200 currently

Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25631837000000 Hz-2.2 dBmV37 dB00
2LockedQAM2561651000000 Hz-2.1 dBmV36.5 dB00
3LockedQAM2562657000000 Hz-2.2 dBmV36.5 dB00
4LockedQAM2563663000000 Hz-1.9 dBmV36.7 dB00
5LockedQAM2564669000000 Hz-1.9 dBmV36.6 dB00
6LockedQAM2565675000000 Hz-1.7 dBmV36.7 dB00
7LockedQAM2566681000000 Hz-1.6 dBmV36.9 dB00
8LockedQAM2567687000000 Hz-1.5 dBmV36.8 dB00
9LockedQAM2568693000000 Hz-1.3 dBmV37 dB00
10LockedQAM2569699000000 Hz-1.1 dBmV37 dB00
11LockedQAM25610705000000 Hz-1.2 dBmV36.9 dB00
12LockedQAM25611711000000 Hz-1 dBmV36.9 dB00
13LockedQAM25612717000000 Hz-0.5 dBmV37.1 dB00
14LockedQAM25613723000000 Hz-0.7 dBmV36.9 dB00
15LockedQAM25614729000000 Hz-0.4 dBmV36.9 dB00
16LockedQAM25615735000000 Hz-0.3 dBmV37.1 dB00
17LockedQAM25616741000000 Hz-0.3 dBmV37.1 dB00
18LockedQAM25617753000000 Hz-0.3 dBmV37.2 dB00
19LockedQAM25618759000000 Hz-0.4 dBmV37.2 dB00
20LockedQAM25619765000000 Hz-0.8 dBmV37.1 dB00
21LockedQAM25620771000000 Hz-0.8 dBmV37.3 dB00
22LockedQAM25621777000000 Hz-1 dBmV37.4 dB00
23LockedQAM25622783000000 Hz-1.2 dBmV37.3 dB00
24LockedQAM25623789000000 Hz-1.3 dBmV37.4 dB00
25LockedQAM25624795000000 Hz-1.4 dBmV37.3 dB00
26LockedQAM25625801000000 Hz-1.6 dBmV37.2 dB00
27LockedQAM25626807000000 Hz-1.5 dBmV37.3 dB00
28LockedQAM25627813000000 Hz-1.6 dBmV37.2 dB00
29LockedQAM25628819000000 Hz-2 dBmV37 dB00
30LockedQAM25629825000000 Hz-1.9 dBmV37.2 dB00
31LockedQAM25630831000000 Hz-1.9 dBmV37.1 dB00
Message 9 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

My post just got deleted!! 

 

CM1150V_cable_baseline_12-15-20_.pngcable_modem_12-25-20_1.png

 

First set of numbers is when I first installed this replacement modem a week ago and the latter two this morning, with no internet connection 

The only real difference is in mumber of correctables (whatever that is????) 

But all the same Downstream and Upstream Channels are Locked, as they were when working, or not. 

 

I have been having similar issues lately 

All was well until mid-Nov or so, after almost a year of working perfectly on my 600Mbps service 

Then I started having serious slow down and drop outs and EVERY morning would have to power cycle the modem, when it would work perfectly again for a while 

Xfinity checked my lines and signal back to the street and all was perfect - they connected an XB7 modem and that has been perfect for about 3 weeks.

Then my replacement CM1150V arrived about 10 days ago and I reconnected that 

Again it was working perfectly until yesterday, when started having same issues as with the previous modem 

 

One quirk I have found - I used to correct it by power cycling the modem; now I have found if I request repeated Speed Tests (I use the Ookla App) then after severel fails (no internet) it will eventually hit - the first one that reconnects shows a very slow download of only a few Mbps, but 18Mbps Up (which is my spec) - and the subsequent test then immediately returns 600. This lasts a while and then it drops off again. (even during the composing of this message)

Now again, this new modem has been perfect for about 10 days and the exact same problem started happening again yesterday. 

There is definitely something about Xfinity service that this modem model does not like. 

 

Now I don't have the Upstream issues that you have @Santa_Cruzer but the symptoms are certainly very similar - there is another thread specific to the Upstream problem if you search in this forum. 

 

Message 10 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

 
Message 11 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

 
Message 12 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Sorry for multiple posts - not sure why images are not showing 

 

 

Message 13 of 27
Santa_Cruzer
Guide

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Not sure this is related, but my download speeds were capped out at 450 mbps, never above it.  When I put in new cable modem, T25, it ran the same speeds,  Today, over 600 mbps download.  Not complaining, but leads me to suspect ISP is changing things on their end.  Could be pushing some modems to fail?

Message 14 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Does anyone know what firmware the CM1150V ships with?

I didn't take note of it when I installed last week 

Now is V4.02.02 

I'm wondering if Xfinity has pushed an update recently which may have coincided with the first modem issues, and now with the new modem? 

Message 15 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

This is the error log - problems started yesterday 

Not sure what that indicates 

 

error_log.png

 

 

Message 16 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

fyi  - https://community.netgear.com/t5/Cable-Modems-Routers/CM1150V-Upstream-Channel-Problem-with-Xfinity/...

 

If I do 'factory reset' does it revert to original firmware it shipped with? 

 

Edit - I did factory reset - the firmware version did not change (so either it shipped with that, or doing a reset does not downrev it) 

 

I should also mention that my 'Upstream' LED flickers, as per the linked thread above - even though all the upstream channels show 'locked' 

Message 17 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Ignore the flickering Upstream LED - brain fade moment - that LEd is solid, it's (of course) the Ethernet Traffic LED that is flickering (as it should) 

Message 18 of 27
FURRYe38
Guru

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Factory reset do not change FW. Just settings. 


@decosse wrote:

fyi  - https://community.netgear.com/t5/Cable-Modems-Routers/CM1150V-Upstream-Channel-Problem-with-Xfinity/...

 

If I do 'factory reset' does it revert to original firmware it shipped with? 

 

Edit - I did factory reset - the firmware version did not change (so either it shipped with that, or doing a reset does not downrev it) 

 

I should also mention that my 'Upstream' LED flickers, as per the linked thread above - even though all the upstream channels show 'locked' 


 

Message 19 of 27
FURRYe38
Guru

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Anything can happen  with ISPs. SIgnal quality, amount of custimers on there main line at the same time, etc...


@Santa_Cruzer wrote:

Not sure this is related, but my download speeds were capped out at 450 mbps, never above it.  When I put in new cable modem, T25, it ran the same speeds,  Today, over 600 mbps download.  Not complaining, but leads me to suspect ISP is changing things on their end.  Could be pushing some modems to fail?


 

Message 20 of 27
TrunkMonkey
Tutor

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

@Santa_Cruzer 

 

Did you ever find a solution for this?  I also have CM1150v with seemingly identical issues that are only temporarily addressed by power cycling the CM1150v or using the rented XB7.  With the XB7, I still have intermittent high latency issues and some bandwidth loss, but never so bad that it requires a power cycle.  There are other posts here that mention that when the upstream signal of the 1150v reaches 48 dBmV that bandwidth drops. 

 

I have a comcast tech scheduled to checkout my line tomorrow, at my own expense.

Message 21 of 27
FURRYe38
Guru

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 

https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...

Message 22 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

My problem was 100% an issue further up the line from my interface at my home.

Two techs had been out and said 'everything was good' 

I asked the second tech NOT to close the ticket and to escalate to line/network. He also gave me local Supervisors card. 
I contacted the local supervisor (it was awkward timing over the Christmas/New Year period) but we connected by phone ultimately. He committed to have line/network investigate.

What I did for my own part in the interim was eliminate the TV Splitter to improve the signal levels to my modem. 

Next morning my internet went out and I thought 'here we go again' - then my wife mentioned she could see TWO trucks down at the main road (one actually at a subterranean box on the sidewalk out on main road and another at the intersection of that street and the one that intesects with mine). I went across the road and spoke to the technician - he said there was certainly higher levels on my line, although not what they would say 'out of spec' - however he swapped the circuit anyway (I do not know whether he swapped my line to another circuit, or whether he replaced some interface board in the box) 

Afterwards I could immediately see improved signal levels at my modem. 

That is now 3 full months since they did that correction out on the main road and it has been absolutely flawless since. 

 

Your symptoms were exactly similar to mine - at 48db upstream, it was troublesome - removing the splitter dropped the level down a bit (but in my case it was over 59 with the splitter in place). Replacing the modem with a brand new Netgear replacement made no difference - well let me clarify that - I had a temporary XB7 modem and did not have the problem; thinking 'it must be the modem' I eventually got Netgear to authorize a replacement.  That actually worked fine for about 2 weeks before the exact same issues manifested themselves. 
With all the issues which were ultimately resolved by line/network I insisted on credits from Xfinity for both the temporary XB7 rental charge and loss of service use. I was satsified with the level of service given to this resolution. 
Ultimately I also decided to eliminate Xfinity TV and switch to YouTubeTV - that got rid of the splitter permanently and also the TVBoxes Equipment and DVR charges - I retained the same service level of Internet service. I'm saving about $60/month with Xfinity Internet +YouTubeTV - also REALLY happy with YouTubeTV relative to Xfinity TV - it exceeded my expectations. 

 

Hope all that helps - you need to try to move it further up the chain than the FIrst Response Tech who does your home service check. I was polite but firm in not accepting there was nothing wrong. Even if 'supposedly' within their 'acceptable' specs it is clear the Netgear is less tolerant at those higher upstream power levels - but it IS a recommended device from Xfinity so they need to do what is necessary to make it work. 

Message 23 of 27
decosse
Apprentice

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

p.s. I just did a quick check of my Upstream Power Levels - 2 channels at 46 and two at 45.5 (should note that I have no splitter installed and that would raise those levels by about 3 db - I cannot comment on whether or not the old problem would be present with the splitter installed.)

But these levels are lower than I had at any time before. I had 47 when I first installed the replacement Netgear modem (it worked when first installed) and I am quite sure that number was with the splitter removed. 

Message 24 of 27
Talisman12
Initiate

Re: CM1150V modem frequent and long reconnects more recently - upstream channel issue.

have this exact same issue. Either no connection or slowed to a crawl for 30+ mins. Comcast saw no issues on their end. All my wiring checked out. T3 timeouts and higher upstream levels as well. Skipped the hoobaloo with comcasts techs. Replaced with a Arris 6183 which is working fine now. 2 year old 1150V modem which im keeping for another house. Worked fine till a week ago when it started timing out.

 

Model: CM1150V|DOCSIS 3.1 Nighthawk® Multi-Gig Speed Cable Modem for XFINITY® Voice
Message 25 of 27
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