What Is the Waterfall Model?

In waterfall model, there are various phases which need to be followed from sequentially one phase to the next. The waterfall model is a traditional project management procedure in which sequential development process is followed. Also in this model, development actually moves in downward direction. It also consists of few phases like initiation, analysis, design, build, test, and maintenance. Nowadays, agile is often preferred over the waterfall model. But sometimes ther is no alternative to a waterfall model, i.e. in archtecture and construction.