A few minutes each day

Over the last few months a problem has begun to crop up where we will lose connectivity for about 1 or 2 minutes.  At first it was doing it maybe a few times per week and it seemed to occur most often between the hours of 12-1pm but now it is occuring at least once per day and happening at just about any hour.

Our internet connection works great otherwise, and i'm glad that the disconnects have been limited  to only short durations so far, but that is still enough to disrupt our VoIP traffic, cause any pending transfer to fail, and wreak havic with our VPN.

Every time it occurs I can log into our gateway at 10.1.10.1 and witness the modem slowly going through the steps to reconnect until it finally does.

Our SNR is usually pretty constant at around 36 dB on all 4 channels.  Downstream power ranges from 2.37 to 4.8 dBmV.  Upstream power is 38.75 dBmV on both channels.  From what I understand, these are all acceptable values.  I'm confused as to what the problem might be.