Intermittent "No Ranging Response received - T3 time-out"

You need to also post the modem's signal status.

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

The stats at that snapshot in time were fine. Is there a router / WiFi in the mix here ? If so, for a test, does a computer hardwired directly to the router device with an ethernet cable have the same problem ?

I'll try to specifically grab a snapshot the next time its acting up.

Yes, I did earlier testing with the internet connection going straight from the modem to my desktop PC and we still saw the  T3 upstream issues periodically.

I'm not referring to the T3's at this moment. Those can happen no matter what (even if nothing) is connected to the modem. I'm talking about if you are experiencing actual connection drops / lapses, not just the log entries ?

Yes, I experience interruptions in connectivity on my devices as a result of this.

If I'm streaming doing voice chats in Discord I stop being able to send packets up, but I still receive downbound packets for a few more seconds. Then I lose all connectivty and the upstream light starts flashing on the modem. Powering off and on always resolves the issue. All devices on wi-fi and wired connections are affected. Sometimes it happens once and then is fine for hours. Sometimes, I have to reset the modem multiple times within a 10 minute period.

I specifically had my desktop PC wired directly to the modem, removing the wi-fi hubs from my setup temporarliy and had the same upstream connection loss occur.

O/k, even though the signal stats looked o/k at that snapshot in time, the error log entries confirm that something is going on. Perhaps there is intermittent noise ingress into the line(s) somewhere.

There are other signal stat figures 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 that are available to these boards. They can check the CMTS (Cable Modem Termination System) 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 for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !

Hello DigitalDeckard. We appreciate you visiting and posting on the Xfinity Forums. I can assist with troubleshooting your Internet timeouts issue. In order to have a better insight, I will have to poll the CMTS for real-time and historical RF signal reports from your modem, and check your local Node/Plant for signal degradation / errors. Please send me a private message and include your full name so I can access your equipment.