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
Analog aur Digital Signals
Signal Kya Hota Hai?
Signal ek aisa medium hai jiske through data ek jagah se doosri jagah travel karta hai. Iska use data ko represent aur transfer karne ke liye hota hai.
Computer Networks mein do main type ke signals hote hain:
1. Analog Signals
Analog Signal ek continuous signal hota hai jo time ke saath smoothly change hota hai. Isme values beech mein kuch bhi ho sakti hain, fixed nahi hoti.
Diagram:
Ye ek smooth wave jaisa hota hai (jaise sine wave).
Real-Life Examples:
Humari awaaz jab telephone line se jaati hai
FM/AM radio signals
Analog TV ka signal
Features:
| Feature | Description |
|---|---|
| Continuous | Smooth aur lagataar change hota hai |
| Amplitude | Wave ki height ya strength |
| Frequency | Wave kitni fast vibrate kar rahi hai |
| Phase | Wave ka timing shift |
2. Digital Signals
Digital Signal ek discrete signal hota hai jisme sirf fixed values hoti hain — mostly 0 aur 1.
Ye steps ya square wave ki tarah dikhai deta hai.
Diagram:
Real-Life Examples:
Computer ke beech mein data transfer
USB se file copy karna
Wi-Fi, Ethernet, Digital Audio/Video
Features:
| Feature | Description |
|---|---|
| Discrete | Sirf 0 aur 1 ka use karta hai |
| Easy to Store | Hard disk, SSD mein store ho sakta hai |
| Less Noise | Noise se kam effect hota hai |
Analog vs Digital
| Feature | Analog Signal | Digital Signal |
|---|---|---|
| Nature | Smooth aur continuous wave | Step-by-step ya square wave |
| Values | Infinite (beech ke values bhi possible) | Fixed values – sirf 0 aur 1 |
| Noise Sensitivity | Zyada noise effect karta hai | Kam noise ka asar padta hai |
| Storage | Difficult to store | Easy to store |
| Example | FM radio, telephone call | Internet data, file transfer |
| Use in Network | Old telephone, modems | Wi-Fi, LAN, fiber, routers |
Conversion Devices
Kabhi-kabhi analog aur digital signals ko convert karna padta hai. Iske liye ye devices use hote hain:
| Device | Kaam |
|---|---|
| Modem | Digital to Analog aur Analog to Digital |
| ADC | Analog to Digital Converter |
| DAC | Digital to Analog Converter |
Real-Life Analogy
| Signal Type | Real Life Example |
|---|---|
| Analog | Dimmer switch (light smooth increase/decrease) |
| Digital | Normal switch (sirf ON ya OFF) |
Summary
| Topic | Kya Yaad Rakhein |
|---|---|
| Analog Signal | Smooth wave jaisa signal (voice, radio) |
| Digital Signal | Step wala signal (0-1 based) |
| Main Use | Analog: Purane systems; Digital: Modern computers |
| Shape | Analog = curve, Digital = square |