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: 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 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.