Topic: 1 How The Internet Works?

1: Brief History: Web 1.0 → Web 3.0

🌍 Web 1.0 (1990s – early 2000s) – The "Read-Only" Web

• Websites were static with no interactivity.

• Built using HTML and CSS (no JavaScript).

• Users could only read content; there was no user engagement.

• No social media or real-time interactions.

• Example: Early Yahoo! pages, simple blogs.

🚀Web 2.0 (2004 – Present) – The "Read-Write" Web

• Enabled dynamic and interactive experiences.

• Technologies like AJAX and JavaScript allowed live updates without page reloads.

• Social media, e-commerce, and cloud applications emerged.

• Users could generate content (comments, reviews, blog posts, real-time chats).

• Example: Facebook, YouTube, Twitter, Amazon.

Web 3.0 (Emerging) – The"Decentralized" Web

• Uses blockchain technology to ensure decentralization.

• AI-driven and privacy-focused to give users more control over data.

• Example: Cryptocurrencies, smart contracts, decentralized apps (Ethereum, Filecoin).

2: Basics of Computer Communication & Data Transmission

📡Data Transmission & Packet.

• The internet sends data in packets, which are small chunks of information.

• Each packet has:-

• Header (destination and sender information).

• Payload (actual data being transferred).

• Uses TCP/IP protocols to ensure data reaches the right destination.

🔗Two Types of Communication

• Wired (Ethernet, Fiber Optics) – More stable and faster; used in offices.

• Wireless (Wi-Fi, 5G) – Provides flexibility but can be slower.

3: Domain Names, IP Addresses, MAC Addresses, and Routing

🌍IP Address (Internet Protocol Address)

• A unique number assigned to every internet-connected device.

• IPv4 (xxx.xxx.xxx.xxx) has 4.3 billion addresses.

• IPv6 provides a larger address space for the future.

🖥️MAC Address (Media Access Control)

• A unique identifier assigned to a device’s network adapter.

• Example: 00:1A:2B:3C:4D:5E.

• Used within local networks but not on the broader internet.

🌐Domain Names (Example: www.google.com)

• Human-friendly names mapped to IP addresses via DNS (Domain Name System).

• DNS servers resolve domain names into IP addresses.

📍Routing

• Routers and gateways direct traffic efficiently.

• Packets take different routes to reach the destination efficiently.

4: Overview of ISP & DNS Functionality

🌐 Internet Service Providers (ISP)

• Companies like Jio, Airtel, BSNL provide internet access.

• They act as intermediaries between users and the global internet.

🔗How DNS Work

• A user types www.google.com in a browser.

• The browser contacts a DNS server to get the IP address.

• The DNS translates the domain into an IP (e.g., 142.250.183.206).

• The browser connects to the website’s server using the IP.