A network security diagram maps out the security methods implemented to protect an organization's assets. It helps to ensure the protection of valuable information as it is stored and transmitted. Before you set up a complex network, one of the first things you should do is draw a network diagram so you know how everything will operate together. The diagram depicts a network architecture in visual form. It's easy to understand how peripherals, firewalls, servers, and mainframes will coexist and function together.