Visitor
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2 Messages
Repeated T3 Timeouts Every ~50 Minutes After Two Tech Visits
Hi there, I’m hoping to get some help with an issue that’s still happening after two technician visits.
I’m continuing to see “No Ranging Response received – T3 time-out” errors, and they occur on a very regular interval of about every ~50 minutes. Here are a few recent examples from 12/21:
20:58:12
21:47:14
22:36:38
During my most recent technician visit, the tech removed a loose 3.5 dB splitter and connected my modem directly to the main coax line (so there are no splitters in the home), and he confirmed the coax readings were in spec on his meter. Even with that, the issue continued with no improvement.
My upstream OFDMA transmit power consistently sits around ~50 dBmV, which I understand is borderline/high for DOCSIS 3.1 and can lead to ranging failures. The T3 timeouts continue, especially in the evening. Before switching to my current Arris G36, I was also experiencing packet loss and instability on the Xfinity-provided modem, so the issue appears unrelated to the modem itself. I’ve also tried two different Ethernet cables.
To test outside of gaming, I also ran multiple pings to Cloudflare’s DNS (1.1.1.1). Most tests were clean, but one test showed around 2% packet loss, including a timeout, and I occasionally see latency jump from ~6 ms up to ~30 ms. The intermittent nature of the loss matches the timing of the T3 errors and further suggests an upstream issue rather than anything inside my home.
Additional info:
Current modem: Arris G36 (DOCSIS 3.1)
Downstream power/SNR are normal
Legacy upstream QAM is normal (~45–46 dBmV)
Only the OFDMA upstream remains borderline/high (~50 dBmV)
T3s mainly appear in the evening/night
Coax line tested good on the technician’s meter
Since two tech visits have already addressed the in-home wiring, the coax tested good, and the problem persists even when connected directly to the main line, I’m wondering if this could be a return-path or node issue outside my home.
If possible, could someone check for upstream noise or any node/plant issues in my area and let me know if this should be escalated to maintenance?
Thank you very much. I really appreciate any help you can provide.
XfinityAlyssaA
Official Employee
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2.3K Messages
21 days ago
Good evening @user_i12hrr, and thank you for reaching out on our Community Forums with your ongoing T3 timeout issues, we appreciate it. I see that you stated you have had two technician visits, I'm sorry to hear that your issue is still occurring. We can check your signal levels and see if there are any node issues affecting your area. To get started, can you please send us a Direct Message with your first and last name along with the service address on the account?
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EG
Expert
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115.3K Messages
21 days ago
@user_i12hrr @XfinityAlyssaA
Please circle back here and post any possible solutions for the issue here in these open public 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.
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user_i12hrr
Visitor
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2 Messages
6 hours ago
Since my original post, I’ve continued to monitor the modem diagnostics and event logs. I am still seeing repeated DOCSIS 3.1 upstream OFDMA profile assignment changes, along with CM-STATUS messages showing Event Type Code 24. The upstream profile continues to fluctuate between multiple profiles over short periods of time.
In addition, my modem logs show a history of T3 timeouts, and I have now experienced at least one T4 timeout, which suggests intermittent loss of upstream communication with the CMTS.
I’ve also noticed that the upstream OFDMA transmit power is not fully stable. While generally within spec, the OFDMA power level will periodically spike to around 50 dBmV and then drop back to 49 dBmV, often around the same time that profile changes occur.
During the most recent technician visit, the technician performed a packet loss test and was able to observe packet loss firsthand, which helped confirm that the issue was present at the time of the visit and not solely based on historical logs.
These behaviors continue even after:
Three technician visits
Replacement of connectors
Premise wiring is being checked and is reportedly within spec
Given the combination of upstream profile flapping, Event Code 24 messages, fluctuating OFDMA transmit power, observed packet loss, and now T3/T4 timeouts, this seems more consistent with intermittent upstream ingress, return-path noise, or a node-level issue, rather than a simple signal-level or premise wiring problem.
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