In order, the components of a STEP Application Protocol (AP) are shown
as:
- Application Protocol Scope, including input and output definition.
- Application Activity Model (AAM), specifying information
requirements and usage/context.
- Application Reference Model (ARM), containing the information model
in application experts language.
- Application Interpreted Model (AIM), which maps the ARM to the STEP
information model, using detailed EXPRESS language.
In addition, "Conformance Classes" define requirements for software
implementing the AP, and "Test Cases/Suites" are used to certify
software implementations.