Visitor
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6 Messages
Xfinity and Arris role in upstream power levels
I thought I would share my experience to help others who have struggled with the same issue.
Symptoms: Dropped video and audio feeds on Zoom, Teams, FaceTime across wired and wireless connection using Xfinity Internet service and a new Arris G34 Router. If found this problem showed up related to numerous Arris Routers with Xfinity Internet.
The reader’s digest is that when you have only internet service from Xfinity (without a Set-top box or TVs connected via coax, the QAM Power level does NOT fall into the 45 - 51 dBmV range that Arris routers expect. This results in lost / dropped connections.
The solution is to get the setup “tuned” to the right power level. The Arris people helped me log into my router and navigate to Connection - WAN, then look at the QAM upstream values to identify the problem. I called Xfinity and when I described the problem, the agent immediately scheduled a service call, without doing more trouble shooting. The Xfinity rep came out, looked things over and commented that they usually only set the QAM Power to be 55 dBmV or lower. He thought Arris was a little finicky with their range. That said, he added 2 two-way Coax connectors to my setup to create the “fake load” of extra devices and got my QAM upstream values to 48.xxxx.
Everything’s been fine for the past 24 hours, so I’m crossing my fingers.
I guess it would not hurt if Arris built some intelligence into their device to “adjust the upstream signal” for people who only use the routers for internet.
If I had not found the solution, this router was going back to the store for another brand.
That said, I did spend upwards of 30 hours getting to the bottom of this problem, including another Xfinity service call last weekend. I’m hoping I save you some of the time/energy I spent to get to the solution.
BruceW
Gold Problem Solver
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26.3K Messages
3 years ago
Arris began saying that upstream power should be "at least 45 dBmV" several years ago. I don't know why, because it's complete nonsense. The upstream power levels are controlled automatically and continuously by Comcast's equipment and do not need to be above 45 dBmV. That's because, as long as upstream power is not maxed out, what's important is not the level at the modem, it's the level (and quality) of the modem's signal as received at Comcast, which they attempt to keep as close as possible to 0 dBmV by adjusting the modem's transmit power. In fact, many customers have service that works perfectly fine with upstream modem power levels below 45 dBmV. Some even operate with the upstream below 35 dBmV.
Comcast's signal level ranges are given in https://forums.xfinity.com/conversations/your-home-network/connection-troubleshooting-tips/602da777c5375f08cdea3db9. If Arris' products did not work in those ranges, CableLabs and Comcast would never approve the devices.
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user_1d33c2
Visitor
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6 Messages
3 years ago
Hi Bruce,
I’m not sure what your point is.
I had a problem. Trouble shot it after 10 days of dropped internet video calls (I am on 20+ calls a day). I seem to have found the problem by having Comcast adjust the power levels, after guidance from Arris level 2 support.
You state Arris should work below 45 dBmV, when mine clearly did not and Arris guided me to adjust those settings.
Hmmm…
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auroramike1
Regular Visitor
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24 Messages
3 years ago
I am seeing exerping everything, except I have yet to see a solution... Just today Arris told me the same thing.
I opened a similar thread.
However I have a cable box and the tech put in a 2 way splitter then a 3 way splitter in front of the modem in hopes to correct the issue... still no luck.
https://forums.xfinity.com/conversations/your-home-network/6-bounded-upload-channels-multiple-issues-for-months-countless-tech-visits-need-line-tech-support-not-level-1/622a5e386c4cd02237d41e99
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user_1d33c2
Visitor
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6 Messages
3 years ago
Sorry to hear you have been having problems for so long.
Per my thread you commented on, this sounds similar to my problem.
What seem to have helped me was repeating to each Comcast support rep.
“Arris states the problem is the Upstream QAM needs to be between 45 and 51
dBmV power level. Can you send someone who can adjust that issue?”
your values are all still below 45.
I will say that Comcast attempted multiple changes to their side of the net work before coming out and kept calling to ask if the service was working properly.
Each time I would check the upstream QAM values, which improved, but did not all land in the required range, so I told them the service was not working properly (it went from failing on 80% of my calls to only 15%, but was still unstable.
Best of luck!
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user_1d33c2
Visitor
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6 Messages
3 years ago
Update: March 12, 2022
So here I am 2 days later and guess what? I had dropped video and audio calls yesterday even though my QAM Upstream and Downstream values were all in range!
I spent 30 minutes on the phone with a Level 1 Arris support rep “Andrew” who claimed he knew as much as a Level 2. *NOT*
His trouble shooting involved: Reset the modem to factory default. Change some WiFi Channel values. Restart Modem. Run Speedtest.net. His conclusion was either a bad modem with two options: “We can send you one once you send yours back at your expense and pay $15 - $50 shipping OR Pay for the new modem with a credit card hold, until we get yours back, but still pay $15-$50 shipping. If the replacement modem does not work, you need to call Comcast again.
He forgot to mention option 3: I return the modem within the 30 window to where I bought it. I chose the latter.
I thanked Andrew and said “Gotta go now”.
I called Comcast and arranged for them to ship me their XB7 Modem that will cost me $14/month + tax. It comes with a 30 day money back guarantee. If this puppy doesn’t work, I will not chase the ghost of dropped signal/internet session. Instead, another provider (1 Gb up and down) will get my business in a couple of weeks.
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NoNoBadPuppy
Problem Solver
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542 Messages
3 years ago
FWIW, Arris is not the only brand of modem/router that have trouble when line conditions are not what is expected.
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Moto_MIA
Visitor
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1 Message
3 years ago
Add me to another Arris/Xfinity user with the same issue. I was given the same instructions by Arris support. Not going to waste my time calling Xfinity/Comcast. Will call AT&T instead and look into their Fiber offering.
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