2 Messages
SYNC Timing Synchronization failure - Failed to acquire FEC framing
Hello -
In early September after Hurricane Idalia, we had Xfinity come out because our overhead cable was down. Service was fine, but the cable was across our neighbor's driveway and was a safety issue.
When the tech came out, he told me that there was something wrong with the service levels and he found that the problem was before it came into the house. So he re-ran a line and Xfinity came back out a few days later to bury it from the pole to the back of our house. Ever since the new line was installed, we've been having problems with our internet where Google Mail, as an example will report that it's offline and then a few minutes later will reconnect. Or a page I'm trying to browse will result in a "not connected" error and after a few refreshes, will pop up. Typical Xfinity speed test shows ~25 mbps download and ~20 mbps upload, latency 35 ms.
Today, I checked out the event log for my Motorola and found several "critical" priority events with "SYNC Timing Synchronization failure - Failed to acquire FEC framing" as the description. There are others as well, but this is the most common.
Does this indicate that there is still a problem with the service coming into the house? I'm on a Mac and don't have a device with an ethernet port to test the connection after bypassing the router. If anyone has any troubleshooting tips for me to help determine if I need to have Xfinity come back out, I'd greatly appreciate it!
BruceW
Gold Problem Solver
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26.4K Messages
2 years ago
Could be, but we need more information. Please post your Internet plan speed and the following information from your modem or gateway (from http://192.168.100.1:
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user_cuqsnh
8 Messages
2 years ago
Thanks for taking a look!
Internet: Download as fast as 800 Mbps (from statement)
Model number: Motorola AC1900 Router
For the event log below, when MAC address was all zeroes, I left it as is since this is not identifiable and could be helpful. Otherwise, I replaced the MAC address with "XXX".
NOTE: the hurricane was end of August, more than 12 days ago, but I think we've had a power outage since then.
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BruceW
Gold Problem Solver
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26.4K Messages
2 years ago
"AC1900" is not a model number, it's a Wifi designation. You can check which device model numbers are approved for a given Internet plan speed at https://www.xfinity.com/support/devices. (Something strange is happening on that page. Before today, it listed "All Compatible Devices", but now it only lists "Recommended Devices", a drastically reduced number. Hmmmmmm.)
But aside from that, the downstream power levels and SNR values look good, although the error counts seem high for 12 days of operation. But the upstream specs are borderline to out of spec (too high), and the event log entries show a device struggling to maintain connection to Comcast's network.
If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. It may well be that Comcast messed something up when they installed the replacement line, in which case you'd need to have them back out to correct the problem. If they determine that the problem is inside rather than outside you'll probably have to pay for the visit (approx $100) unless you have their Service Protection Plan ( https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it).
Good luck!
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user_cuqsnh
8 Messages
2 years ago
Thanks, again, @BruceW !
For those following this thread, the URL for the PDF document listing all compatible devices (including Hitron) can be found here:
https://assets.xfinity.com/assets/dotcom/projects/cix-4997_compatible-devices/2023.08.07%20Full%20List%20of%20Compatible%20Devices.pdf
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BruceW
Gold Problem Solver
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26.4K Messages
2 years ago
A later version of that document is at https://assets.xfinity.com/assets/dotcom/projects/cix-4997_compatible-devices/2023.09.25%20Full%20List%20of%20Compatible%20Devices.docx-%20vF.pdf. As zandor60657 pointed out, the MG7550 isn't approved for the 800 Mbps tier. Using devices on speed tiers for which they are not approved tends to produce unexpected results. Consider picking up one of the devices approved for 800 Mbps service, or dropping back to a lower tier.
Aside from that, the 50 plus upstream power levels will be a problem for any modem or gateway and really need to be corrected. These need to be below 50, ideally between +40 and +45 dBmV.
Good luck!
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BruceW
Gold Problem Solver
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26.4K Messages
2 years ago
If you are going to replace your gateway, you can try that first. If that doesn't correct the sync-timing errors and you've done all Troubleshooting you can do, then yes, arranging a return visit from Comcast would be the way to go.
Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.
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user_cuqsnh
8 Messages
2 years ago
Hello - I installed my new Netgear CAX80 modem/router on Friday 10/13/23 and although my speed test is much better, I'm still getting errors and intermittent disruptions in service. Does my upstream look too high? Does any of this warrant a call to Xfinity to have someone come out and check the line?
Here's my current info:
Status
Profile ID
ID
MER
Number Range
Codewords
Codewords
Codewords
Event Log:
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BruceW
Gold Problem Solver
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26.4K Messages
2 years ago
Sorry to hear that. The downstream power level and SNR values look great. Four of the five upstream channels also look good, but #5 is borderline/too high, and the event log looks about as bad as it did before. Just a guess, but it looks to me like an intermittent connection problem. Since you're still having problems I'd suggest asking Comcast to come back out and try again. If they bill for the visit you can try to persuade them that it's a call-back on work that should have been performed correctly the first time.
Good luck!
Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.
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