U

Visitor

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2 Messages

Sun, Apr 4, 2021 7:02 PM

Relatively consistent T3 timeouts requiring modem restart

I've been having this problem where my modem (Netgear CM1100) has too many T3 timeouts and requires a power cycle in order to reestablish internet connectivity. This has been happening every couple days (usually 2 times a week on any day of the week). The weird part is that it only has happened from 11am to 1pm CST (I live in Texas).

This normally wouldn't be an issue because a single power cycle fixes the issue, but I do livestreaming for my church during that 11am-1pm time frame, and I have had issues maintaining my livestream. While livestreaming, sometimes my upload speeds hit zero or <1mbps (I'm usually uploading at 3mbps with a ~6mbps internet upload plan), but the speeds recover after 10 seconds or so (kind of off-and-on). However, when the T3 timeouts keep happening and my modem locks up (as in I can't load http://192.168.100.1/ anymore), then I have to completely pause the livestream and power cycle my modem to reestablish my connection.

I encountered this 11am-1pm issue with two of my older modems, which led me to buy the CM1100 in hopes that it would fix the problem (Narrator: it didn't). I was using a Netgear CM400 when I moved to my current house back in July 2020 (an Xfinity tech came to hook up the cable from the street), and I didn't have this 11am-1pm T3 timeout issue. I don't remember the timeline too well, but I think this issue began happening around Fall 2020, then disappeared Winter 2020, and then reappears in Spring 2021. I remember when I encountered the issue in Fall 2020, I hooked up my CM400 modem directly to the coax cable entry point in the house's wall panel (also tested with an even older Arris SB6121). However, this did not fix the issue. But as I said earlier, the 11am-1pm issue went again for a couple months before coming back in Spring 2021.

Throughout this whole time, I've been monitoring my modem's cable connection stats, and they've (all 3 modems I've tried) been in normal ranges. I can post a screenshot of the stats from my CM1100. I can't really think of why this issue seems to occurs on random days but always in the same timeframe around lunch time. I'm hesitant to make an Xfinity tech come look because it's likely that nothing will look wrong during the visit + a single power cycle has always fixed the problem.

Any ideas?

Responses

Official Employee

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147 Messages

3 m ago

Hello, @user_79566d! That is very odd that the issue is only popping up within that specific timeframe. I'm wondering if there are any errors within the connection between the modem and the network that's related to the activity going on during that time to cause that. Let's find out together and help get this fixed! Please send me a Message with the full name of the Account Owner and yourself, if different, as well as the address on file.

 

A Message can be sent by clicking on the Chat Bubble icon in the upper right corner and then searching "Xfinity Support". Thanks!

EG

Expert

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87.2K Messages

3 m ago

@user_79566d @ComcastKaitlan 


Please post any possible solutions for the issue here in the open forums so that all readers here may benefit from the exchange / info. This is in keeping with the spirit for which these public help forums were originally intended. Thank you.

BruceW

Gold Problem Solver

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22.4K Messages

3 m ago

... and then searching "Xfinity Support" ...

"Search for Xfinity Support" is not good advice, as the only "search" that appears on the initial peer-to-peer screen won't find "Xfinity Support" unless the user has already sent a message to them or received one from them.

Instead:

  • Click "Sign In" if necessary
  • Click the "Peer to peer chat" icon or https://forums.xfinity.com/peer-to-peer-chat
  • 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
  • Type your message in the text area near the bottom of the window
  • Press Enter to send it

See https://forums.xfinity.com/conversations/email/cant-create-a-new-email-address/605e52b726aa974d63032d02?commentId=606107ea738c7f46a02b830e

Visitor

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2 Messages

2 m ago

Update: after text chatting with xfinity support, they reprovisioned my modem (4/7). I didn't see much change to my modem connection stats - the downstream bonded channels' power levels increased to ~3 to 4 dBmV, and everything else is still in the normal ranges.

I also started livestreaming at a lower bitrate (2.5 mbps 720p, down from 3 mbps 1080p).

It seems that one or both of these changes have helped me hold my connection for the past 2 weeks. Checking my modem's event log, I did find that the modem did have a few T3 timeouts (one on 4/9 8:40am, two around 4/13 midnight, and one on 4/17 4:40pm), but those were self-resolved and I didn't have to power cycle my modem to re-establish my internet connection. Besides those T3 timeouts, I also saw some "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing" messages when I had the T3 timeouts on 4/13...not sure if it's related or not.

All in all, things look fine right now!

EG

Expert

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87.2K Messages

O/k so FWIW. Re-provisioning the modem cannot and does not have anything to do with the connection quality.

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