Our apartment is using the Xfinity Internet. We first identified the connection issue by seeing frequent lost conncection notification from different services on almost all devices. We started troubleshooting by restarting the modem and carefully reconnecting the cables. We also tested on a Ethernet connected PC to filter out the impact of wireless router. We eventually logged into the modem to check the cable connection status. Here is the screenshots of the status page and the event log:
The downstream seems OK, but the upstream power is at its maximim. (And we are aware of there is only one US channel locked. Hopefully that's not an problem.) The T3 timeout occurs all the time since two weeks ago. In fact, the T3 recorded time in the screenshot is exactly when we logged into the page. Suggested by the high US power, extreme frequent T3 timeout, and constant connection loss on the application layer, we suspect that there is some physical connection or cable issues from our model to the local hub.
We believe the assistance from Xfinity is required since we have done almost all we can do on our side. As we are all working from home, the Internet problem becomes critical and we hope it can be fixed fast. Could you please send techical support or let us know what should we do next?
The upstream power is on the high side and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.
In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.