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Badcorgi
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6 Messages

Fri, Oct 9, 2020 12:00 PM

Netgear CM1150V Internet Connectivity

Bought a Netgear CM1150V Cable Telephony Modem to accommodate my new Xfinity Gig Service on 8/26.  Had lightning fast speed (945/48) for about 10 days until internet connectivity began to falter while streaming Xfinity TV on my tablet.  Internet speed went down to ~1-5mbps/0 mbp.  Rebooted and factory reset modem and router a million times.  Xfinity tech was out 3 times and each time said line was all clear, no issues with others in my area.  Xfinity even laid a new cable line from the node to my house.  Still, same conncetivity problem.  Brought it to the attention of Netgear.  Downstream bonded channel power is between -1.1 and .8 dBmV and upload channel speeds are 47-48.5 dBmV.  Event logs consistently show "critical" priority issues with messages: "Started Unicast Maintenance Ranging - No Response received - T3 time-out" or "16 consecutive T3 timeouts while trying to range on upstream channel 1" or "Unicast Maintenance Ranging attempted - No response - Retries exhausted."  So Netgear sends me a replacement modem.  While waiting for the replacement, I reinstall my Arris Surfboard SVG2482AC.  Works fine with consistent internet.  No problems.  Netgear replacement CM1150V arrives, I call Xfinity to assist with installation this time.  After an hour with tech on the line and several reboots, the modem is successfully installed.  Two days later, I am back to where I was with my initial modem.  I now have inconsistent, mediocre internet service.  When it works, this modem is incredible, but when it is not, it is tortoise slow.  If it gets worse, I will have an expensive paperweight in my office and will reinstall the Arris Surfboard with the hopes one day it will be fixed.

My point: I am convinced Xfinity and Netgear need to refine the interface between the physical product and the service because it clearly DOES NOT WORK, at least not consistently.  I anticipate the day when a new firmware update will resolve this but it will take good faith cooperation between the two companies to fix these bugs.  I am hardly alone here as I see the same issues with others in the Netgear and Xfinity community forums.  Any input is welcome.  Thanks.

Responses

New Poster

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4 Messages

7 m ago

Yesterday I tried to switch from an older Arris model to a brand new Arris SB6190 modem. 

1) The first issue was "your mac id is incorrect". OK. I DO know how to read, but sent them a pic showing I had that ability.

2) Some MAC ids aren't in their db, apparently.  This had to be sent to someone else to enter, so that took a bit

3) Took them 4 tries to get it provisioned. Really awful speeds.

4) Then Im told it requires a service call.  Huh???

Facts are:

Im getting 5-10MB down and 8-10 up on the new modem.  That's directly connected via ethernet.

They can't simply revert to my old modem, because they decided its "no longer supported", even though its maybe 3 years old. So Im stuck with that.

When I connect to the "XfinityWiFi" network, Im getting similar bandwidth as the modem.

There is obviously something upstream causing these issues.  They need to just admit and own it, and fix the problem.

 

New Poster

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2 Messages

5 m ago

Any updates if you were able to fix the issue. I am exactly in the same situation. My Arris SVG2482G works absolutely fine. I got the replacement now for CM1150v from Netgear. I am not sure if I have to connect it or keep using my Arris? Either way money on Netgear is down the drain. 

Badcorgi

Frequent Visitor

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6 Messages

5 m ago

Yes, the problem (so far) has been resolved.  My internet speed is lightning fast (usually 850 to 945 mbps/35-45mbps) and has been consistent.  Not sure what happened but if your modem remains under warranty (I think it is 1 year?) by all means, contact Netgear and have them send you a new one.  My original one arrived by mail through Best Buy (I don't like them either) and who knows what that modem went through getting here.  The new modem seems to be working fine and I rarely, if ever, had a slow down problem.  It really helps to have an Xfinity tech (call during the day because you will not get someone from India) input the correct MAC address to recognize the modem.  Hope that helps.  Good luck with your issues, but definitely don't let Netgear get away with a faulty product.  I think it was them all along.

1113361

Contributor

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28 Messages

4 m ago


@Badcorgi wrote:

Event logs consistently show "critical" priority issues with messages: "Started Unicast Maintenance Ranging - No Response received - T3 time-out" or "16 consecutive T3 timeouts while trying to range on upstream channel 1" or "Unicast Maintenance Ranging attempted - No response - Retries exhausted."  So Netgear sends me a replacement modem. 

 

Yes, the problem (so far) has been resolved.

I have/had EXACTLY these same issues 

First CM1150V worked perfectly for almost a year - then started having connectivity issues that required a power cycle of the modem EVERY morning and frequently throughout the day. Overnight I got a whole bunch of these same errors you reported in your opening post. 

 

An XB7 Xfinity modem installed by Xfinity Tech (who reported the lines were clean and well within spec) resolved the issue instantly and was perfect 

Received my replacement CM1150V and initially it too was perfect - after about 12 days, it is now exhibiting exactly the same issue as the first modem - I am now wondering if Xfinity pushed a Firmware 'upgrade' (sic!) to them which is why they went from working one day to not the next

 

I did not note what rev firmware my replacement was on when I first installed (and working correctly) - it is now V4.02.02 

@Badcorgi  - can you check what rev firmware is in your CM1150V currently (while it is presumably still working) ? 

 

Badcorgi

Frequent Visitor

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6 Messages

4 m ago

Modem is still working and I have no apparent problems.  Firmware version is v4.02.02.  I dread waiting for the next shoe to drop hoping I don't have any problems in the future.  Although modem performance has been optimal (945mbps/40mbps), I have reviewed the logs and have noticed on very specific occasions there were actual "Warnings" with the following message:

REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=28:80:88:d5:14:40;CMTS-MAC=00:01:5c:65:1c:64;CM-QOS=1.1;CM-VER=3.1;

Sometimes the errors are "Critical," and other times, a "Notice."  I still believe Xfinity and Netgear need to remedy the incompatibility of their products.  I see similar experiences by those who purchase the rival Arris T25.  Good luck with your newer modem.

1113361

Contributor

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28 Messages

4 m ago


@Badcorgi wrote:

Modem is still working and I have no apparent problems.  Firmware version is v4.02.02. 




Appreciated 

Hope it all stays well for you 

ComcastRob

Official Employee

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248 Messages

4 m ago

Hi there! I'd be glad to ensure that this gets looked into further. Please click on my handle (ComcastRob) and send a private message with your name, the complete service address (including city, state, ZIP, suite number, etc), and the phone or account number, and any pertinent details-- like the ticket number(s)-- so we can help. 

I am an Official Comcast Employee.
Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!tick

New Poster

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1 Message

4 m ago

I have the same issues, was this ever resolved?

1113361

Contributor

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28 Messages

4 m ago

Check the Power Levels (go to the Modem Admin log in) 

My Upstream Power levels were about 51dBmV with the 3.5db Splitter installed (for TV's)  - about 48 with the TV Splitter bypassed. It would not lock at all with the splitter installed and connected but kept dropping Internet even with it removed

Had Techs out twice who claimed all was OK at the house end - I contacted the local Technical Operations Supervisor and he sent out a Line/Network Crew - they swapped out my connection down on the Main Road and now I have ~ 44dBmV and it has been perfect since. 

So if you show high Upstream power signal levels, you might request the same - you'll have to get a tech out initially because he will have to escalate it - insist and ask for the local supervisors contact info. 

Badcorgi

Frequent Visitor

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6 Messages

4 m ago

Yes, it seems to have been remedied by Netgear sending a new modem to replace the one I purchased from Best Buy.  So far, so good.  I also wanted to add Comcast techs had been at my house at least three times and each time, they said there was no problem with the connection, which I believe to be true.  They even swapped out the old line at the cable connection box on the street.  I also believe the Netgear product was the source of the problem.  I hear folks who buy the Arris Surfboard T25 had similar issues with connectivity.  I just hope the problem as been solved permanently before the year warranty expires.

1113361

Contributor

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28 Messages

4 m ago

I really don't think it's the modem - at 48dBmV on upstream it is right on the threshold for that device 

Mt problem was IDENTICAL to yours - I had the modem swapped out by Netgear and it worked perfectly for 2 weeks until the power level crept up a bit.

I did a baseline when I installed the replacement and it was at 47 with the 3.5dB Spliiter - when the problem started happening again, it was at 51 with the Splitter installed; I removed the splitter and it connected but with frequent drop-outs and reboots required (this on the second unit). 

After the techs reconfigured the street connection the levels are down at 44dBmV and the same modem has now been perfect again for the last couple of weeks. 

My conclusion is that 47dBmV is about the absolute max this device will tolerate working reliably 

I should also add that a temporary XB7 from Xfinity worked flawlessly, immediately replacing the first CM1150V - I believe it will operate at a higher power level without dropping (it was at 49dBmV with the Splitter)  

 

Summary 

FIrst Installed (with Splitter) - 47dBmV - worked for 2 weeks, no issues

Problems started again - 51dBmV - constantly losing internet, to point it would not lock at all 

Removed Splitter - 48dBmV - works for a while then loses Internet, worse in Evening and Overnight. 

New Connection at Street - 44dBmV (no splitter) - has been perfect again. 

 

Same CM1150V works when power < 47 - fails consistently when higher. 

I did not measure the original CM1150V but the symptoms identical in both modules (and also same as yours) 

 

Maybe you got replacement one with slightly better operating tolerance, or your power levels have dipped just a little bit. If your issues re-surface, check the power levels (get a baseline now anyway) 

Badcorgi

Frequent Visitor

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6 Messages

4 m ago

Thanks for the insight.  I don't know what the upstream power levels were at with the previous modem but right now, I have 4 channels at: 48.3 dBmV, 48.8 dBmV, 48.5 dBmV and 45.3 dBmV respectively.  I will keep an eye on upstream power levels if there are any future issues. 

New Poster

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4 Messages

4 m ago

I have the exact same modem and it took comcast forever to configure it correctly. I sent the 1st one back because tech support couldn't getting working correctly, so they said it may be the modem. Installed the 2nd one and they still couldn't get it working right. I have the 1GB DN/40 UP plan and I wasn't getting speeds over 300MB. After multiple techs and esculated calls one tech finally flashed it w/ the correct firmware or config file and it finally began to work correctly but not before driving me out of my mind. During the weeks comcast was trying to figure it out, I rewired every bit of ethernet from my modem/router/switch/pc's to Cat6e thinking that was it and it wasn't. All has been good since.

Badcorgi

Frequent Visitor

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6 Messages

4 m ago

Thanks for sharing your experience.  Mine was similar upon receiving my second modem.  It seems the tech that day, after about an hour or more on the phone, finally got the modem to work correctly.  It comes back to my original theory that Xfinity and Netgear need to work more closely to make the equipment as compatible as possible with the service provided.  

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