Software Life Cycle Model

Software Engineering is the systematic approach to the development, operation, maintenance, and retirement of software. All Software products can be developed with the help of a Software Process i.e. Software Life Cycle. This Software Process is nothing but a series of identifiable stages that a software product undergoes during its lifetime. And this series basically starts with a Feasibility Study Stage, Requirement Analysis and Specification, Design, Coding, Testing and Maintenance. Each of these phases is called the Life Cycle Phase. And this Software process is achieved, with the help of software life cycle model (or process model). A Process Model is a descriptive and diagrammatical model of a software Process. A process model identity

e.g. the corresponding phase-entry criteria for the Software Requirement Specification phase can be that the software Requirement Specification document has been completed, internally reviewed, and approved by the customer. With such well-defined entry and exit criteria for various phases, it becomes easier to manage and monitor the progress of the project. Thus, we can say that life cycle models encourage development of software in a systematic and disciplined manner. Due to the above fact, the developer should adhere to well-defined life cycle model. Thus, a major advantage of adhering to a well-defined life cycle model is that it helps to control and organize systematically various activities of the product, which is taken to develop. When a life cycle model is adhered to, the developer can easily tell at which stage (e.g. design, code, testing) of development, the project currently is. If no life cycle model is adhered to, it becomes very difficulty to chart the progress of the project and the developer may face a problem known as the 99% complete syndrome. In this syndrome, which appears when there is no definite way to access the progress of the project, the optimistic developer feels that the project is 99% complete, even when the project is far from its completion. Success or completion of project is heavily dependent upon which type of life cycle model the developer is going to adhere. So a life cycle

Most data flow modeling methods use four kinds of symbols. These symbols are used to represent four kinds of system components: processes, data stores, data flows and external entities. The data flow diagrams for the current project are show in the following figure. It is the data flow diagram for the entire process. It specifies the major transform centers in the approach to be followed for producing the software. This is the first step in the structured design method. In the project, the inputs are the packets that are flowing in the network interface that is set to promiscuous mode. The output is the information contained in the packets in human readable form, which is stored in the output file.
The context diagram and data flow diagram of the proposed system are given as