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
Transmission Media in Computer Networks
Transmission Media Kya Hota Hai?
Jab do devices (jaise computers, mobile phones ya routers) ek dusre se data share karte hain, to data ko ek jagah se doosri jagah pahuchne ke liye rasta chahiye hota hai.
Ye jo rasta ya channel hota hai, jisse data travel karta hai, use hi Transmission Media kehte hain.
Transmission Media Kyu Zaroori Hai?
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Data ko send/receive karne ke liye medium zaroori hai
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Ye medium decide karta hai:
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Kitni speed se data jaayega
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Kitni door tak jaa sakta hai
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Kitna secure hai
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Kitna costly ya cheap hoga
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Transmission Media Ke Types
Transmission media do categories mein divide hota hai:
1. Guided (Wired) Media
2. UnGuided (Wireless) Media
1. Guided Media (Wired Media)
Ismein data cable ya wire ke through travel karta hai. Ye media secure, reliable, aur fast hota hai.
a) Twisted Pair Cable
Do copper wires ko twist karke banaya jaata hai taaki interference kam ho.
Types:
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UTP (Unshielded) – ghar/office mein use hota hai
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STP (Shielded) – industrial areas mein use hota hai
| Feature | Detail |
|---|---|
| Speed | 100 Mbps – 1 Gbps (Cat5, Cat6) |
| Distance | 100 meters tak |
| Use | LAN, telephone line |
| Cost | Sasta |
b) Coaxial Cable
Ismein ek central copper wire hota hai, jise insulation aur shielding se cover kiya jaata hai.
Use hota hai: Cable TV, CCTV cameras
Diagram:
[Copper Core]
↑
[Insulation]
↑
[Shielding]
↑
[Outer Jacket]
| Feature | Detail |
|---|---|
| Speed | 10 Mbps (basic use) |
| Distance | 200-500 meters |
| Use | TV signals, old LAN |
| Cost | Moderate |
c) Optical Fiber Cable
Ismein data light pulses ke form mein bheja jaata hai. Ye sabse fast aur secure media hota hai.
Types:
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Single-mode (long distance)
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Multi-mode (shorter distance)
Optical Fiber Cable mein:[Glass Core] → Light Travel
[Cladding] → Light reflect karta hai
[Coating] → Protection
| Feature | Detail |
|---|---|
| Speed | 100 Gbps+ |
| Distance | 10+ kilometers |
| Use | Internet backbone, ISPs |
| Cost | Mehenga, par worth it |
| Security | Highly secure, no interference |
2. Unguided Media (Wireless Media)
Ismein data air mein travel karta hai, bina kisi cable ke — jaise Wi-Fi, mobile networks.
a) Radio Waves
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Signals har direction mein jaate hain
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Wall ke paar bhi jaa sakte hain
| Feature | Value |
|---|---|
| Range | Few meters to kilometers |
| Use | Wi-Fi, FM, Bluetooth |
| Frequency | 3 kHz – 1 GHz |
b) Microwaves
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Straight line mein travel karte hain
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Satellite aur telecom towers mein use hota hai
| Feature | Value |
|---|---|
| Range | 30–50 km |
| Use | Satellite, telecom towers |
| Frequency | 1 GHz – 300 GHz |
| Note | Line of sight hona chahiye |
c) Infrared
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Short range communication
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Wall ke paar nahi jaa sakta
| Feature | Value |
|---|---|
| Range | 1–5 meters |
| Use | TV remote, wireless mouse |
Comparison – Wired vs Wireless
| Feature | Wired Media | Wireless Media |
|---|---|---|
| Physical Medium | Cable ya wire | Air |
| Speed | Fast (especially fiber) | Moderate to fast |
| Cost | High (fiber), Low (twisted) | Generally low |
| Security | Secure | Thoda risky (hacking possible) |
| Setup | Time-consuming | Easy & mobile |
Quick Summary
| Medium | Best Use |
|---|---|
| Twisted Pair | Ghar, Office LAN |
| Coaxial | TV, Security camera |
| Fiber Optic | Internet backbone, ISP |
| Radio Waves | Wi-Fi, FM, Bluetooth |
| Microwaves | Satellite, Telecom communication |
| Infrared | Remote control, short distance |
Final Thoughts
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Transmission Media = Rasta jisse data ek device se doosri device tak jaata hai
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Wired = Cables jaise twisted pair, coaxial, fiber
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Wireless = Air through radio, microwave, infrared
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Har media ka apna speed, cost, range aur use case hota hai
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Use case ke hisaab se sahi media choose karna important hota hai