Network design is designed for communication within the devices. All the devices are designed to transfer data but network makes a link to travel. Network makes a link in real world for communication that is in real term. System of a network is designed to transfer data within the modern era. Modern era is made to comfort user and make a channel of network. Network diagram is made for signal transfer and data transfer. Network is made for the flow of data and information is transferred within the domain. The system of design is according to user as every system has a different network. Network flow is according to the user requirement and they make a chain of flow of data. Data security is the real security that is done in network. The network after analysis of data flow makes a system. System flow of a network makes data design complete so that the design is done in real way. Design of a network is complicated as it is made on flow of data within the system. System needs a confirmation of data flow and flow requires knowledge.