Thanks. That was very informative and makes things a lot clearer.

So essentially hops that display no information w/100% packet loss are just not configured to be visible, and are not necessarily indicative of problems at those hops, right?

I'm troubleshooting my Comcast line and everything looks good out to about five hops from me (a series of Comcast addresses) and then there are about five hops with no info and 100% packet loss in a row before the last few hops are normal again. That's why I'm asking.