Design product component interfaces using established criteria.


Interface designs include the following:

  • Origination
  • Destination
  • Stimulus and data characteristics for software, including sequencing constraints or protocols
  • Resources consumed processing a particular stimulus
  • Exception or error handling behavior for stimuli that are erroneous or out of specified limits
  • Electrical, mechanical, and functional characteristics for hardware
  • Services lines of communication

The criteria for interfaces frequently reflect critical parameters that should be defined, or at least investigated, to ascertain their applicability. These parameters are often peculiar to a given type of product (e.g., software, mechanical, electrical, service) and are often associated with safety, security, durability, and mission critical characteristics.

Refer to the Identify Interface Requirements specific practice in the Requirements Development (RD) (CMMI-DEV) process area for more information about identifying product and product component interface requirements.

Example Work Products

  1. Interface design specifications
  2. Interface control documents
  3. Interface specification criteria
  4. Rationale for selected interface design


1. Define interface criteria.

These criteria can be a part of the organizational process assets.

Refer to the Organizational Process Definition (OPD) (CMMI-DEV) process area for more information about establishing and maintaining organizational process assets.

2. Identify interfaces associated with other product components.

3. Identify interfaces associated with external items.

4. Identify interfaces between product components and the product related lifecycle processes.


For example, such interfaces could include the ones between a product component to be fabricated and the jigs and fixtures used to enable that fabrication during the manufacturing process.

5. Apply the criteria to the interface design alternatives.

Refer to the Decision Analysis and Resolution (DAR) (CMMI-DEV) process area for more information about analyzing possible decisions using a formal evaluation process that evaluates identified alternatives against established criteria.

6. Document the selected interface designs and the rationale for the selection.