For the last several weeks we have been getting frequent cable modem reboots. The model logs say these are due to T4 timeouts. In the last 1.5 weeks we have called support and they had us disconnect from the router to discount it as this issue. While disconnected from the router we still had the timeouts. Just recently I move the modem off the splitter and connected it directly to the incoming line. Still having timeout issues.
Here are the logs from right after the most recent reboot without a splitter involved.
Nov 11 2012 18:16:47
No Ranging Response received - T3 time-out;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;
T4 errors indicate that your modem was unable to contact the headend for a long time. It usually indicates an intermittent signal problem. Your power levels/SNR are fine. Next time it happens, grab another set of signal levels and post pls. Also call Comcast and request:
• Upstream Signal to Noise Ratio (SNR): Above 30 is acceptable. Higher is better. • Upstream Receive Power: Ideally this number should fall within the -7dBmV and +7dBmV range.