I typically have a home system that is connected to a work VPN all the time. I've noticed that I'll have to reconnect it some days and they do appear to correspond to my cable modem log entries. Even if does disconnect, it doesn't appear to be for a long time, but still somewhat annoying when it does happen. My setup is straight from vault to house w/ 1 two way splitter before going to cable modem. Signals and logs attached. Signals look good to me, just unsure about logs.
The stats as read at the modem level at that moment in time were o/k but there are three additional signal stats that can also cause those "Critical Errors" which can't be read by the modem. They can only be read from their end by them polling the CMTS (Cable Modem Termination System) at the local headend facility.
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.
You can call in and ask what these figures are. The Upstream Receive Power Level should fall within the range of -2dB to +2dB with 0dB being in the middle and perfect.
The Upstream SNR should be least 31dB, and the higher it is the better.
The ICFR should be no higher than 2 dB.
You could have an intermittent noise ingress issue in only the upstream channel(s) / return path only somewhere.
They will be able to see whether or not everything is in the green zone and also see a history plot for the modem.
Hey, can you go more into depth what your problem is like? Do you get kicked off the internet with/without VPN, then reconnects shortly after?
Most time Cisco AnyConnect reconnects within a minute or so. Sometimes it's a hard kick where I have to reauthenticate. Both instances internet is out for a short period.
Who should I have level 1 support refer to? They most often just say to call back when there is an active issue w/o really digging into the problem. Annoying is what it is.