Protocol, the abbreviation of network protocol, network protocol is a set of protocols that both computers must abide by. For example, how to establish a connection and how to identify each other. Only by observing this protocol can computers communicate with each other. Its three elements are: grammar, semantics and time sequence.
In order to make data reach the destination from the source on the network, the participants in network communication must follow the same rules, which are called protocols, and the protocols are finally embodied in the format of data packets transmitted on the network.
Protocols are often defined as several levels, and the definition of hierarchy is to make the changes of protocols at one level not affect those at other levels.
Computer communication network is formed by the interconnection of many nodes with information exchange and processing capabilities. In order to make the whole network work orderly, it is required that each node must abide by some pre-agreed rules about data format and timing. These rules, conventions or standards established to realize network data exchange are called network protocols. Protocol is a protocol or call rule designed by both parties to realize communication.
Network is a place for information exchange. All computers connected to the network can exchange information through their physical devices, including the most common cables, optical cables, wireless WAP and microwaves. However, it is impossible to exchange information only by owning these physical devices.
Just as the human body cannot lack the control of the brain. Information exchange also needs a software environment. This software environment is some rules agreed by human beings in advance, which are called "protocols". With the protocol, different computers can use physical devices according to the same protocol, without causing "incomprehension" between them.