The definition of ‘functional requirement’ is that it essentially specifies something the system should do.
The definition for a non-functional requirement is that it essentially specifies how the system should behave and that it is a constraint upon the systems behaviourbehavior. One could also think of non-functional requirements as quality attributes for of a system.
Simply, the difference is that non-functional requirements describe how the system works, while functional requirements describe what the system should do.
functional requirements includes:
functional requirements includes:
- Business Rules
- Transaction corrections, adjustments and cancellations
- Administrative functions
- Authentication
- Authorization levels
- Audit Tracking
- External Interfaces
- Certification Requirements
- Reporting Requirements
- Historical Data
- Legal or Regulatory Requirements
Non-functional requirements:
Non-functional requirements:
- Performance – for example Response Time, Throughput, Utilization, Static Volumetric
- Scalability
- Capacity
- Availability
- Reliability
- Recoverability
- Maintainability
- Serviceability
- Security
- Regulatory
- Manageability
- Environmental, Data Integrity