In this model, Each phase of EDLC is executed sequentially. It links a formal analysis & design methodology with highly structed development phase.

The flow is undirectional .

O/P of each phase serves as input to next phase.

This model has drawback of assuming all the analysis can be done and everything will be at right place without any implementatior OR review.

Also the bugs in the current design are removed only after support phases.

This model is opted for product development where the requirements are well defined and within the scope & changes are not expected till the product is finished.