Computer Networks
CN Part-1
- What is a Computer Network?
- Goals and Applications of Computer Networking
- Computer Network Components
- Types of Computer Networks
- Network Topology
- Difference between Client Server and Peer to Peer Network
- Layered Architecture in Computer Networks
- Protocol Hierarchy in Computer Networks
- Interfaces and Services in Computer Networks
- Connection Oriented and Connectionless Services
- Service Primitives
- OSI Model
- TCP/IP Model
- Difference between OSI Model and TCP/IP Model
- Encapsulation and Decapsulation in Computer Networks
- Queueing Models in Computer Network
CN Part-2
- Physical Layer in Computer Networks
- Transmission Media in Computer Networks
- Analog and Digital Signals
- Data Rate and Bandwidth
- Encoding Techniques
- Multiplexing in Computer Networks
- Transmission Modes in Computer Networks
- Data Link Layer
- Framing in Data Link Layer
- Flow Control in Data Link Layer
- Error Control in Data Link Layer
- Error Detection and Correction in Computer Networks
- Stop and Wait Protocol
- Sliding Window Protocol
- SDLC(Synchronous Data Link Control) Protocol
- High-Level Data Link Control (HDLC) Protocol
- Point-to-Point Protocol (PPP)
CN Part-3
- MAC Sublayer and MAC Addressing
- Channel Allocation Methods
- ALOHA Protocol (Pure and Slotted ALOHA)
- CSMA/CD and CSMA/CA in Computer Networks
- Ethernet (IEEE 802.3)
- Wireless LANs (IEEE 802.11, Wi-Fi, and Bluetooth Basics)
- Network Layer and Design Issues
- IPv4 and IPv6 Protocols
- Addressing: IP Address, Subnetting, and Supernetting
- Routing Algorithms: Static vs Dynamic, Distance Vector, and Link State
- Routing Protocols: RIP, OSPF, and BGP
- Packet Switching and IP Fragmentation
- Network Layer Protocols: ICMP, ARP, RARP, DHCP, and NAT
CN Part-4
- Transport Layer and Functions
- Process-to-Process Delivery, Ports, and Sockets
- TCP Segment and Three-Way Handshake Connection Establishment
- UDP (User Datagram Protocol): Format and Features
- Flow Control and Error Control in Transport Layer
- Congestion Control: Leaky Bucket, Token Bucket, and TCP Congestion Control
CN Part-5
- Application Layer Architecture and Principles
- Domain Name System (DNS)
- Email Protocols: SMTP, POP3, and IMAP
- File and Web Protocols: FTP, HTTP, and HTTPS
- Remote Access Protocols: Telnet and SSH
- World Wide Web (WWW) and Web Architecture
- Network Security Basics: SSL, TLS, and Cryptography Fundamentals
World Wide Web (WWW) and Web Architecture in Computer Networks
World Wide Web (WWW) kya hai?
World Wide Web (WWW ya simply the Web) internet par interlinked hypertext documents, multimedia files aur resources ka ek global information system hai.
Ise 1989 mein CERN (Switzerland) mein Sir Tim Berners-Lee ne invent kiya tha taaki scientists aapas mein research papers aur data aasani se share kar sakein.
Internet vs World Wide Web (Exam Difference!):
– Internet ek global physical infrastructure hai (computers, cables, routers, switches ka network).
– World Wide Web (WWW) internet ke upar chalne wali ek Application Layer service hai jo web pages aur links ke format mein data present karti hai.
(Analogy: Internet highway system hai, aur WWW us highway par chalne wali delivery cars mein se ek hai).
Three Foundational Pillars of the Web
World Wide Web teen fundamental technological pillars par khada hai:
+----------------------------------------------------+
| The World Wide Web (WWW) |
+----------------------------------------------------+
|
+-------------------------------+-------------------------------+
| | |
[ URL / URI ] [ HTTP / HTTPS ] [ HTML ]
(Locates Resources) (Transfers Resources) (Formats & Displays)
1. URL / URI (Uniform Resource Locator)
Internet par available har web page, image, video ya document ka ek globally unique standard address hota hai jise URL kehte hain:
-> Scheme / Protocol: https (kaise access karna hai).
-> Host: thehingineer.com (kis server par hai).
-> Port: 443 (optional, default 80 for HTTP, 443 for HTTPS).
-> Path: /computer-networks/osi-model (server ke andar file ka location).
-> Query String: ?lang=hi (parameters passed to server).
-> Fragment Anchor: #layer4 (page ke andar specific section jump).
2. HTTP / HTTPS
Web browser (client) aur Web server ke beech web resources exchange karne ka communication protocol (Request-Response model).
3. HTML (HyperText Markup Language)
Standard document formatting language jo text, links, images, tables aur multimedia ko structure karti hai taaki browser use render kar sake.
Evolution of Web Architecture: Web 1.0 vs Web 2.0 vs Web 3.0
| Web Era | Nature | Characteristics & Examples |
|---|---|---|
| Web 1.0 (1990s) | Read-Only Web | Static HTML pages, zero user interaction, content creators publishing for passive consumers (e.g., Britannica Online, early personal websites). |
| Web 2.0 (2000s – Present) | Read-Write (Social) Web | Dynamic web apps (AJAX, JavaScript), user-generated content, social networks, centralized platforms (e.g., YouTube, Facebook, Wikipedia, Twitter). |
| Web 3.0 (Emerging) | Read-Write-Own (Decentralized) | Decentralized architectures, Blockchain technology, P2P networks, Semantic Web, self-sovereign identity with zero central monopoly. |
Web Caching and Proxies
Modern web traffic ko optimize karne ke liye Web Proxy Caches aur CDNs (Content Delivery Networks jaise Cloudflare, Akamai) use hote hain. Client ke paas sthit edge server popular web content ko local storage mein cache kar leta hai jisse origin server par load nahi padta aur user ko web page millisecond speeds par load hota hai.
Summary Table
| Web Concept | Summary |
|---|---|
| Inventor | Sir Tim Berners-Lee at CERN (1989). |
| Core Technologies | URI/URL (Addressing), HTTP/HTTPS (Transfer), HTML (Formatting). |
| Internet vs Web | Internet is the global hardware infrastructure; Web is an information service running on top of it. |