Visitor
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2 Messages
Internet connectivity loss several times every day
Hi! We've never had great internet reliability, but due to our new jobs my wife and I really need a reliable connection now. I just got a new brand new Motorola 8611 to replace our Netgear CM500 to see if that would make a difference and we are still having issues. When the internet goes out, it's not our internal network because both our wired and wireless clients have no issue talking to each other. This issue has persisted on both a Ubiquiti USG router and a Synology AX6600 router. But again, our internal network never goes down. Only the internet. When the internet goes out, there is always an entry in the cable modem log. The first screen shot below is roughly around the time my wife reported that it went down. The 2nd and 3rd images show log entries that I witnessed happen at the exact time reported. What seems to happen is we get a series of errors with a timestamp but then get errors with no timestamp? Any help is diagnosing this would be greatly appreciated. We even had Comcast come out and run a new line from the box to the side of our house. Same issue.
EG
Expert
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110.3K Messages
2 years ago
Your post with those pics of the error log entries was made "Private" by the forum software because it contains CM MAC and the CMTS MAC addresses. They are considered to be personal information. The posting of personally identifiable information is a violation of their forum guidelines. Please delete those pics.
What you can do instead is to copy and paste all of the text (instead of using an image) but you'll need to redact all of the CM MAC and CMTS MAC addresses. The forum bot will not allow your post to be seen publically.
Please also copy all of the text in its entirety of the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers and paste them into your next post.
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catbreath
Visitor
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2 Messages
2 years ago
CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A;
OFDM/OFDMA Profile ID: 3.;
CM-STATUS message sent. Event Type Code: 24; Chan ID: 37; DSID: N/A; MAC Addr: N/A;
OFDM/OFDMA Profile ID: 3.;
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-
Critical (3)
No Ranging Response received - T3 time-out;
Critical (3)
Honoring MDD; IP provisioning mode = IPv6
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EG
Expert
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110.3K Messages
2 years ago
The signal status values at that snapshot in time were OK but the error log entries indicate that something is going on. Perhaps there is noise ingress into the line(s) / an upstream channel / return path impairment somewhere.
There are other signal stat values that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.
I'm going to escalate your issue to the Comcast corporate employees (The Digital Care Team) who are available to these boards. They will be able to poll the CMTS (Cable Modem Termination System) to check for any real-time degradation and / or error reports, see your node / cable plant, and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll the CMTS for those upstream receive signal stats.
You should get a reply here in your topic. Good luck !
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EG
Expert
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110.3K Messages
2 years ago
@catbreath @XfinityXanadu
Here's how to send a direct message (private message);
Click "Sign In" if necessary.
Click the "Direct Message" icon in the upper right corner or https://forums.xfinity.com/direct-messaging
Click the "New message" (pencil and paper) icon.
The "To:" line prompts you to "Type the name of a person". Instead, type "Xfinity Support" there.
As you are typing a drop-down list appears. Select "Xfinity Support" from that list.
An "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://comca.st/3KQF8q9 for an example.
[Permission from and credit given to BruceW].
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