Seventeen years after I started working on my EIGRP book, the reverse engineering days were over: RFC 7868 is the definitive guide to modern EIGRP (I’m not familiar with at least half of the concepts mentioned in it).

Just in case you’re interested in a bit of historical trivia:

• My EIGRP deciphering history started a few years before the book was published. In mid-1990s I was asked (as an external trainer) to create an EIGRP course for Cisco EMEA Training.
• I’ve never seen any internal EIGRP documentation or code – everything I knew about EIGRP I’ve learned from trying out crazy stuff and deciphering debugging messages.
• Two of the RFC authors (Russ White and Don Slice) were the technical reviewers for my EIGRP book. Russ copiously rewrote my pidgin English into something understandable – if you like reading my blog posts today, you should (also) thank Russ.