1. Client and Server

• Client → Usually your browser (Chrome, Firefox, Edge) or a mobile app.
  • It requests resources (like web pages, images, or APIs).
• Server → The computer that hosts the website or application.
  • It processes the request and sends back a response.

📌 Example:

When you type https://example.com in your browser:

• Client (your browser) sends a request to the server.
• Server processes it and sends back the HTML/CSS/JS that builds the page.

2. Request-Response Cycle

1. DNS Resolution → Your system finds the server’s IP address for example.com.
2. TCP Connection → Client and server establish a connection (using TCP/IP).
3. TLS/SSL Handshake (if HTTPS) → Secure encryption is set up.
4. HTTP Request → Browser sends a request (GET/POST/PUT/DELETE).
5. Server Processing → Server checks database, runs backend code (PHP, Node.js, Python, etc.).
6. HTTP Response → Server sends data back (status code + content).
7. Rendering → Browser displays the page using HTML, CSS, JS.