Time Warner Cable - Legacy → [Internet] uncorrectables

I got an Arris CM820 modem 8 days ago. I'm pleased that I can access the GUI without disconnecting my phone adapter.

For a week I had zero uncorrectables. Overnight, approximately a thousand appeared on 5 of the 8 downstream channels. The other 3 still had zero.

I'm curious. Does this mean TWC had an outage? Could it happen when they assign me a new IP?

Now I remember! Yesterday afternoon, a neighbor called because she was unable to print documents from her employer's server. Her Windows 8 print spooler was jammed. I'd gotten it working before, but not this time, and the touch screen interface frustrated me.

I took my pocket-sized Mac over there and connected it to her TV. She quickly downloaded and printed the documents. When I got back, a few minutes after I started my computer, I realized I was still on her WiFi network. I plugged in the ethernet cable from my modem, then turned off WiFi. Could that have caused a spate of uncorrectable FEC errors?

1000 uncorrectables isn't really a lot, especially if they happened in a quick burst when you're otherwise going a week without any at all. Some modems also show you the number of successful octets, which puts the uncorrectable errors in perspective.

Could very well be from you bumping the cables when you plugged the network cable in. Or a street light generated a "pop" of noise when it came on, or any number of things that generate electrical disturbances. Generally they're nothing to worry about unless you see them ratcheting up on a regular basis (hundreds per hour).

I see FEC is between my modem and TWC's transmitting device. Detaching me computer, on the other side of my ATA, would have had no effect. I believe modern FEC uses blocks of arbitrary length. To keep overhead low, the blocks may be quiet long. That causes cliff effect, where a single event that might otherwise have affected only one octet, can cause hundreds to be lost. And it took a week to happen!