I came into my office this morning and had no connectivity on any of my computers, or my desk phone that also works over an Ethernet connection. It didn’t take long to figure out why:
After the third image, it briefly powers off, then repeats the process infinitely. Great if I wanted my own desktop light show, somewhat less effective as a communications switching device. Taking it apart I didn’t see any visible damage, we’ll chalk this one up to a random failure inside of an IC somewhere. The switch is about 5 years old, if I remember correctly.