What do you know about network protocols?

Network protocols are a set of rules and agreements that define data formats and principles of interaction between devices in a network. They ensure reliability, routing, and integrity of data transmission.

The most important protocols for Node.js:

• HTTP/1.1, HTTP/2, HTTP/3: The foundation of web communications. Node.js has built-in modules for working with HTTP.
• TCP (Transmission Control Protocol): A reliable, connection-oriented transport layer protocol. Guarantees delivery of data packets and their order.
• UDP (User Datagram Protocol): A connectionless, unreliable transport layer protocol. Faster than TCP, suitable for streaming data and time-sensitive applications.
• TLS/SSL: Protocols for ensuring security and data encryption in networks, often used over TCP for HTTPS.

Examples of usage in Node.js:

// Creating a simple HTTP server
const http = require('http');

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello, world!\n');
});

server.listen(3000, '127.0.0.1', () => {
  console.log('Server running at http://127.0.0.1:3000/');
});

// Example TCP server
const net = require('net');

const server = net.createServer((socket) => {
  socket.on('data', (data) => {
    console.log('Data received:', data.toString());
    socket.write('Data received\n');
  });

  socket.on('end', () => {
    console.log('Client disconnected');
  });
});

server.listen(4000, '127.0.0.1', () => {
  console.log('TCP server running on 127.0.0.1:4000');
});

Understanding network protocols is critical for developing scalable and reliable network applications in Node.js.