A session plan is the set of possible steps that Sentinel may go through when it processes a session. There is a session plan for each type of session that Sentinel supports. Sessions are processed in three phases (see the diagram below). Each phase contains one or more steps.
The term we use for a “step” is a point in session. Sentinel looks up and runs a feature execution script at each point in session. The feature execution script tells Sentinel how to run one or more features. We also, therefore, refer to points in session as features execution points.