Waterfall Model

Waterfall model is sequential development process. This has predefined phases like following:

1. Requirement analysis
2. Architecture/Design
3. Development/Implementation
4. Integration
5. Testing/Validation
6. Deployment
7. Maintenance

The waterfall model moves from one phase to another in sequential manner. The output of one phase is used in next phase. The completion of one phase can be considered as milestones. There are different teams to work on different phases of the waterfall model.

This model is being used by large projects. For smaller projects there are different methodologies being used as spiral model, iterative model, and agile methodology.