A network protocol is a collection of communication rules between all devices (network servers, computers and switches, routers, firewalls, etc.) on the network. ), which specifies the formats that information must adopt in the communication process and the significance of these formats. Most networks adopt hierarchical architecture, and each layer is built on its lower layer, providing some service for its upper layer, while shielding the upper layer from the details of how to realize this service. The rule of communication between N-layer on one device and N-layer on another device is N-layer protocol. There are many protocols at each layer of the network, and the protocols at the same layer of the receiver and sender must be consistent, otherwise one party will not be able to recognize the information sent by the other party. Network protocols enable various devices on the network to exchange information with each other. Common protocols are: TCP/IP protocol, IPX/SPX protocol, NetBEUI protocol, etc.