jwr1221's profile

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5 Messages

Monday, December 12th, 2022 9:17 PM

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Weak signals leading to short dropouts / intermittent connectivity problems.

For the last 2 weeks I've been experiencing connection problems with my internet service.  I am using my own equipment.  Starting at the beginning, I had a Netgear CM1150V modem to support my 800 MB plan.  I am using a separate Asus AX88U router.  From the cable entry point into my home, I am using a single 15ft (?) cable into a splitter with shorter 3 ft cables leading to my modem and TV box.  All 3 cables and the splitter are Comcast supplied items.

I noticed that when on webex calls for work or when on an online game, there would be periods where the connection lagged and took a few seconds to stabilize.  When this would happen, I would see the downstream indicator light on my modem start flashing.  I would also see DNS inquiries jump from <20 ms up to > 5000 ms through monitoring response times on a Raspberry Pi running Adguard home.  After a few minutes the modem downstream light would revert back to solid and things would go back to normal.  Then after 10 mins or so, it would go through the same cycle; over and over.

I called for support and they went through the usual scripted troubleshooting and insisted they couldn't see any issues.  Even when the downstream light was flashing on the modem they claimed everything was fine.  Finally they agreed to schedule a service technician to visit my home.

On Thursday Dec 8, a technician came out and hooked up to the line outside my home.  He said everything inside looked fine but he saw "the low frequencies were very weak" going back to the distribution box in the neighbor's yard.  He filed a "service impacted" report and left.  The next day on Friday Dec 9, I got a text from Comcast stating that work was completed and my problem was resolved.  Unfortunately the problem remained; still seeing an intermittent flashing downstream light on my modem and stuttering on my connections.  (Same issue on multiple devices either connected via ethernet cable or wifi).

I called back for support and went through the whole troubleshooting script again with no resolution.  I had already purchased a brand new modem (Arris SB8200) just in case it was an issue with my equipment.  So I asked them to go ahead and add the new modem to my account and got it provisioned.  I also went through my router settings with a fine tooth comb, eliminated the adguard systems, tried different DNS servers, disabled all protection and firewalls in the router, etc. just to try to eliminate every possible contributing factor.  Using the new modem, the downstream light does not flash, but the problem is still present.  I am still getting stuttering and periodic delays in my connections.  When on a webex call for work, it will pause and advise of a poor network condition.  When playing an online game, the game will stutter as if the connection to the server has been lost.

In looking at the status of the new Arris modem, from what I've read here on other posts, it looks like the downstream channel signal strength is at the very low end of "acceptable" and the transmit power on the upstream channels is quite high.

Curiously, when I open the event log on the modem it is empty, but it was showing some events yesterday.  Is that a sign of an unintended reboot that cleared the log??

This is frustrating when I am experience connectivity problems but every time I call, they can't see any issues on their end.  On my end, two different modems have exhibited the same behavior so I don't think I am imagining things!  Can anyone give me some advice or guidance on those posted signal levels or what I need to try next?

Thank you!

Problem Solver

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528 Messages

2 years ago

Hello, I hope you are doing well! Please send me a private message with your full name and full address. I can most definitely take a further look at this issue. To send a private message, please click the chat icon next to the bell in the upper right corner. Click the “notepad and pen” button. Send the full message to our shared support handle “Xfinity Support”. We look forward to hearing from you!

Problem Solver

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948 Messages

2 years ago

@jwr1221  Is this WiFi or Ethernet?

Expert

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107.1K Messages

2 years ago

@jwr1221 wrote: In looking at the status of the new Arris modem, from what I've read here on other posts, it looks like the downstream channel signal strength is at the very low end of "acceptable" and the transmit power on the upstream channels is quite high.

That is correct. The power levels are borderline. You need to get the techs re-involved in this until it gets fixed properly.

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.


Good luck !

(edited)

New Poster

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5 Messages

2 years ago

Thanks for the input and thanks to @XfinityCrystal for offering to help me investigate further!  And to answer @Jlavaseur , I was seeing the same problem on all devices whether connected via wifi or a wired ethernet connection.

Good news; Problem now appears to be resolved.  I was considering eliminating the TV portion of our Xfinity service since my promotion period was expired and we literally never watch it anyway so I tried an experiment to see if removing the (Xfinity-provided) splitter and cable box from the line would have an impact on the signal levels.  Overall, it improved the downstream signals from the values posted above to around -6dBmV on each channel.  This roughly corresponds to the advertised -3.5dB loss on the splitter.  So signals were better but the lag / stuttering problem persisted.

When I went to my local Xfinity store to remove the TV service from my plan and return the cable box, I explained my troubles to the customer service rep in the store and she scheduled another technician visit for me.  A different technician visited and checked the signals and ended up running a new line to the distribution box (?) which significantly improved the signals; now in the range of +6dBmV on the downstream channels with power levels from 42 to 44 dBmV on the upstream channels.  He mentioned that he connected me to a new panel (?) that was just recently installed.  The next day another Xfinity contractor showed up to replace the "temporary" line from the pervious day and bury the new line.

So far, the problem has not resurfaced so hopefully no more issues going forward.  Interesting that the "temporary" new line the technician ran was an orange coax cable that was visually the same as the cable installed and buried 10 years ago when we purchased our home and subscribed to xfinity internet, but the permanent line looked to be a heavier gauge black line.

Also to note, once the new line was installed, my new Arris SB8200 downstream light switched to blue which I believe indicates a DOCSIS 3.1 "high speed" connection?  My plan includes the 800 Mbps speed service.  At the time I did a speed test and was getting 1060 Mbps down.  A day later, things seemed just a bit slower so I did another speed test and now I'm back down to the "usual" 600 Mbps speed down that I normally see.  So I pay for 800 and the new line is obviously capable of it, but I still seem to be throttled to 600...  Hmm...

Happy that my service seems to be restored, but still irritated that over multiple calls Xfinity continued to insist that they saw no issue on their end and insisted it was problem with my device(s).  As a result I purchased and installed a brand new modem that likely wasn't necessary.

Official Employee

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1.1K Messages

@jwr1221 Thanks for the update! Glad to hear the issue has not resurfaced! With the speeds you're receiving of 600Mbps is this through Wi-Fi or through ethernet? 

Did you still need assistance with changing your tv plan as well?

I am an Official Xfinity Employee.
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New Poster

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5 Messages

@XfinityKei​ :  That speed is measured by the built-in speed test function of my Asus AX88U router, with a direct Gigabit ethernet connection to the modem.  The same speed test function was used to measure both the 1060 Mbps immediately after the repair AND the current value of just under 600 Mbps.  Measuring speeds using devices connected to my network are (as expected) slower than that...  I'm typically seeing around 500 Mbps on an Xbox Series S that has a Gigabit ethernet connection to the router.  Speeds are around 250 or 300 Mbps using a PC connected to a mesh network node (which is using 5Ghz wifi as the backhaul.)

I have already updated my plan at my local Xfinity store so no further changes need there.  But if there is anything you can do to help boost my service up to the rated speed of my plan, that would be appreciated!  :)

Thank you for the follow-up!

Official Employee

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1.3K Messages

It's our pleasure, @jwr1221! And I'm so glad you received the help you needed with repackaging at one of our awesome Xfinity Stores. Have you already reviewed how to Position Your Gateway Like a Pro? There are also tips for Improving Your Network Performance. I highly recommend reviewing those before we continue troubleshooting. If you still have speed concerns, just send our team a private message with your full name and full address so that we can troubleshoot your particular account and equipment. Our Digital Care Team works around the clock to support you and your household, and we're always happy to help however we can!

 

To send a "Direct (private) Message":
• Click "Sign In" if necessary
• Click the "Direct Message" icon (or https://forums.xfinity.com/direct-messaging)
• Click the "New Message" (pencil and paper) icon
• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line
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I am an Official Xfinity Employee.
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We ask that you post publicly so people with similar questions may benefit from the conversation.
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New Poster

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5 Messages

Thanks for the reply @XfinitySara ...  While I agree that both of those links contain valuable information for improving connection stability and speed of the wifi network, I don't think they are applicable to this case.

The speed test is being run by the router itself.  The router is connected directly to the modem with a Gigabit ethernet connection so the condition of the wifi network will not affect the results of the speed test that the router is running.  Using the router speed test function, my speeds were >1000 Mbps immediately after the repair.  A day later with no further changes, my speed has dropped to around 600 Mbps.  The initial tests show that the connection is capable of the full speed of my service subscription, yet it appears my service is being throttled to less than that.  Is that a normal occurrence?

Official Employee

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1.7K Messages

@jwr1221  I can assure you we would never proactively slow down your speeds in any way, so that would not be the case. If you are seeing a fluctuation in speeds again, there could certainly be some other variables involved as @EG stated. We can work on getting a tech out to review this further. You can send us a direct message at anytime.

 

You can start by clicking the chat icon located in the top right corner on your forums page when signed in. Once there, you can search for "Xfinity Support" to compose your direct message. Please add your full name and service address to help us locate your account.

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