Bas said:
Easy. As soon as I saw "Inner Rim" I knew that implied "Outer Rim" and knew what it was.

Edit: Apparently Andy followed the same trail of thought.
Yes.  Although, if you first see "core worlds" and "colonies" (as I did), you might be tempted to think this is from another popular science fiction series.  Pretty easy to recognize where it's really from when you look at the planet names, though.