shockingly large numbers of "computer professionals" have no idea how networks work

Incidentally, if you suspect you yourself are this, I can't recommend any book more highly than Michael W. Lucas's Networking for Systems Administrators. Don't be fooled by the title - the whole idea is to get you to the level where you can talk to a network engineer without looking totally clueless, and no farther - an excellent stopping point.

I would recommend it handily over, say, my own Intro to Networking class in college. And yes, `mtr` is mentioned by name in it!