The Internet is a global network of networks that enables the standardized exchange of data and information between interconnected computers and devices all over the world.

It encompasses various technologies and services including the World Wide Web, electronic mail, file transfer, telephony, and more.

Messages and packets

A message is a unit of data exchanged between communicating entities over the Internet, that typically represents a piece of information, such as a request or a response, sent from one device or application to another.

Messages can vary in content and purpose, depending on the application. For example, in email communication, a message might include the sender's address, recipient's address, subject, and body text.

Messages can be composed of various data types, such as text, images, audio, video, or structured data formats like JSON or XML.

In order to be sent across the network, messages are broken up into smaller chunks of data called packets.

For example, a typical file of 1 megabyte will be split into 685 packets, knowing that each packet has a maximum size of 65,535 bytes.

Each packet contains a portion of the original message, along with additional information, such as source and destination addresses, sequence numbers, error detection codes, and protocol headers.

Packets are transmitted independently across the network and can take different routes to reach their destination, which allows for efficient use of network resources and resilience to network congestion or failures.

At the destination, the received packets are reassembled into the original message by the receiving device or application.

The Internet protocol suite

A communication protocol is a set of rules that defines the syntax, semantics, and synchronization of communication between parties.

A network protocol is a communication protocol that defines how data is transmitted, received, and processed across a computer network.

More specifically, it defines how data is formatted (i.e. the structure of the packets), how it is routed to the correct destination, how it is optimized to avoid network congestion, how errors are detected and corrected (e.g. lost or corrupted packets), and so on.

The Internet protocol suite, commonly known as TCP/IP, is a set of network protocols that work together to ensure that data transmission across the Internet is consistent and reliable.

Is is composed of three protocols:

1. The Internet Protocol