Need help with modem throwing error Dynamic Range window violation. Believe error to be causing modem to reboot numerous times throughout the day. What does it mean and how do i get it resolved?
Modem will periodically reboot several times per day for what i believe to be the Dynamic Range window violation error. Could this be to high SNR? SNR ranges from 39.8-41.8. Any assistance is appreci...
Dynamic Range Window is a concept related to upstream power on bonded channels, so it can't be directly related to your downstream SNR. In general there could never be such a thing as having too high of an SNR.
A Dynamic Range Window Violation occurs when the CMTS asks the modem to set an upstream power level on one channel that is significantly different from the other channels. For example, if one of the channels is at 38 dBmV and then the CMTS asks for another channel to be set to 51 dBmV, that would create a violation because all channel powers need to be within a 12 dBmV range.
I haven't been able to find the exact details, but I think this often happens in response to a very brief spike of noise on the line, since I've never seen the high power level stay in effect long enough to see it in the status page.
The DRW violations on their own probably aren't causing the modem to reboot since they are event level 5 (warning), but when I was having that problem I did get brief upstream issues at the same time as the DRW violation in the log. Look for items in the event log that are event level 3 or lower such as T4 timeouts. Those are more likely to cause the reboots, and of course it's not the T4 itself causing the reboot. It's a problem on the line which causes a T4, and then the T4 triggers a reboot to try to clear the problem.