The IETF process depends on peer review. However, IETF documents
are generally written to be useful for implementors, not for
reviewers. In particular, while great care is generally taken to
provide a complete description of the state machines and bits on
the wire, this level of detail tends to get in the way of initial
understanding. This document describes an approach for providing
protocol “models” that allow reviewers to quickly grasp the essence
of a system.
http://www.potaroo.net/ietf/idref/draft-iab-model/