How RADIUS works...

A few weeks back, I was asked (somewhat informally) to create some documentation describing how RADIUS works (at a pretty high level). I'd figured that I could start out with a piece of a pretty silly, but useful PowerPoint presentation created by one of our engineers that shows how custom attributes are handled in our system (with lots of bells and whistles).

Before doing that, I looked around and found some great source material:

1. Cisco: How Does RADIUS Work?
2. RADIUS: Secure Authentication Services at Your Service
3. An Analysis of the RADIUS Authentication Protocol

The Cisco document, How Does RADIUS Work? is far and away the best introduction I've seen online. It's straight forward and very skimpy on details, but the details are exactly the kinds of things that make non technical people lose it when we're trying to convey basic concepts.

I need to find a way to convey the basics (like the Cisco document) while adding the additional complexity we deal with daily (and need to prepare for). It's still on my to do list...