Traditional SDLC based waterfall model primarily takes care of the analysis phase, then the designing phase, and then the implementation phase to follow, with testing carrying out the whole process. All the phases have definite entry and exit criteria. The transition of this stage is triggered through management decision point by approving the phase end deliverables. This framework is called the Waterfall Model because each phase runs naturally into the next one like water over a series of falls.This model works out as a best suite when the requirements freeze upfront and are well-documented with no uncertainty in the scope. It is usually used to execute small scale projects.

Iterative and Incremental Development is a product development and management methodology that permits iterative project development and cyclic progress assessment. This development methodology is derived from the well documented ‘helix / iterative’ software engineering model.

The Unified Process is not simply a process, but rather an extensible framework which can and should be customized for specific organizations and/or projects. The Rational Unified Process is, similarly, a customizable framework.

Agile Process model is lightweight and highly disciplined process model that consists of simple parallel steps – Analysis of the system requirement, Design and planning, Implementation, and Integration. The main properties of Agile Development which makes it so effective are
• Small Timeline
• Concrete and continuous feedback
• Incremental approach for planning
• Short Documentation
• Flexibility in Development process schedule
• Refined Team