Protocol

Protocol (from the Greek word for primary law) is a set of rules and standards that govern the format, transmission, and delivery of data over a network. It defines how two devices communicate and is used to create a common language that all network-enabled computers, servers, and other network devices understand.

A protocol typically consists of instructions on how a device should send and receive data, as well as how the two machines are to interact. This may include specific commands for synchronization or authentication, the addressing or sequencing of messages, or the format of data or error messages.

When a network has multiple protocols that are able to communicate with each other, it is called a protocol stack. For example, billions of devices such as smartphones and computers connected to the Internet must all use the same protocol stack for communication. This underlying stack includes several layers, such as the physical layer (e.g. LAN wiring), the data link layer (e.g. Ethernet), the network layer (e.g. IP) and the transport layer (e.g. TCP/UDP).

Protocols provide a consistent set of rules and procedures for computers to communicate with each other, enabling information exchange, resource sharing, data transport, and remote access. They also help to ensure the privacy of data travels by limiting access to the data.

Common protocols used in computers and networks are Ethernet, Wi-Fi, IP (Internet Protocol), TCP (Transmission Control Protocol), UDP (User Datagram Protocol), and SSH (Secure Shell). These protocols are responsible for establishing the connection between two or more machines, as well as the packet delivery, session control, authentication, encryption, and other tasks.

Finally, there are several types of networking protocols, such as application layer protocols, transport layer protocols, and network layer protocols. Each type of protocol has its own set of rules and functions that perform a specific task.