A computer network is a collection of interconnected devices, such as computers, servers, and other devices, that can communicate and share resources with each other.

A computer network protocol is a set of rules and conventions that govern how data is transmitted and received between devices in a computer network. These protocols define the format of data packets, the order of transmission, error checking, and other aspects of network communication. Examples of network protocols include TCP/IP (Transmission Control Protocol/Internet Protocol), HTTP (Hypertext Transfer Protocol), and SMTP (Simple Mail Transfer Protocol).

A computer network protocol is a set of rules and conventions that govern how devices communicate and exchange data over a network. These protocols define the format, timing, sequencing, and error control of data transmission between devices. They ensure that data is transmitted reliably and efficiently across the network.

Protocols can be organized into different layers, each responsible for a specific aspect of network communication. The most commonly referenced model for understanding network protocols is the OSI (Open Systems Interconnection) model, which defines seven layers:

1. **Physical Layer**: This layer defines the physical connection between devices, such as cables, connectors, and electrical signals.

2. **Data Link Layer**: Responsible for establishing and maintaining links between devices on the same network segment. It ensures data integrity and handles error detection and correction.

3. **Network Layer**: Handles routing of data between different networks. It determines the optimal path for data packets to reach their destination.

4. **Transport Layer**: Manages end-to-end communication between devices. It ensures that data is delivered reliably and in the correct order.

5. **Session Layer**: Manages the communication sessions between applications on different devices. It establishes, maintains, and terminates connections between applications.

6. **Presentation Layer**: Responsible for data translation, encryption, and compression. It ensures that data is presented in a format that the application layer can understand.

7. **Application Layer**: Provides network services to applications, such as email, file transfer, and remote access. It enables applications to communicate with each other over the network.

Each layer of the OSI model uses specific protocols to perform its functions. For example, the Internet Protocol (IP) operates at the network layer, while the Transmission Control Protocol (TCP) operates at the transport layer. These protocols work together to enable devices to communicate and exchange data across a computer network.