Learning Objectives / सिकाइ उपलब्धिहरू
By the end of this lesson, students will be able to:
यो पाठको अन्त्यमा, विद्यार्थीहरू निम्न कुराहरूमा सक्षम हुनेछन्:
- Define telecommunication and computer networks clearly.दूरसञ्चार र कम्प्युटर नेटवर्कको स्पष्ट परिभाषा दिन।
- Identify the 5 key components of data communication.डाटा सञ्चारका ५ प्रमुख तत्वहरू पहिचान गर्न।
- Differentiate between Guided and Unguided transmission media.तारयुक्त (Guided) र ताररहित (Unguided) माध्यम बीच फरक छुट्याउन।
- Explain network types: PAN, LAN, MAN, and WAN.नेटवर्कका प्रकारहरू (PAN, LAN, MAN, WAN) को व्याख्या गर्न।
Core Technical Competencies:
मुख्य प्राविधिक क्षमताहरू:
- Understand network devices (NIC, Hub, Switch, Router, Modem).नेटवर्क उपकरणहरू (NIC, Hub, Switch, Router, Modem) को कार्य बुझ्न।
- Analyze Topologies (Bus, Star, Ring, Mesh, Tree).नेटवर्क टोपोलोजीहरू (Bus, Star, Ring, Mesh, Tree) को विश्लेषण गर्न।
- Differentiate Client-Server and Peer-to-Peer structures.क्लाइन्ट-सर्भर र पियर-टु-पियर ढाँचा बीच तुलना गर्न।
- Evaluate Internet, Intranet, Extranet & safety advantages.इन्टरनेट, इन्ट्रानेट र एक्स्ट्रानेटको उपयोगिता बुझ्न।
Ready to start the interactive session?
के तपाईं डिजिटल सिकाइ सत्र सुरु गर्न तयार हुनुहुन्छ?
1. Introduction / परिचय
Real-Life Context in Nepal
Imagine sending a photo over Viber or WhatsApp from Kathmandu to Pokhara, taking an online class via Zoom, or paying for snacks using eSewa / Fonepay. All these daily activities rely on Telecommunication & Computer Networks!
काठमाडौंबाट पोखरामा Viber वा WhatsApp मार्फत फोटो पठाउने, Zoom बाट अनलाइन कक्षा लिने वा eSewa/Fonepay मार्फत भुक्तानी गर्ने कार्य सम्झनुहोस्। यी सबै दैनिक कार्यहरू दूरसञ्चार र कम्प्युटर नेटवर्क मा नै आधारित छन्!
Why study this unit? / यो एकाइ किन पढ्ने?
Modern Nepal relies on connected systems for education, banking (Nepal Rastra Bank RTGS), government services (Nagarik App), and tele-medicine in remote hilly districts.
आधुनिक नेपाल शिक्षा, बैंकिङ, नागरिक एप र दूरदराजका जिल्लाहरूमा टेलि-मेडिसिनका लागि जोडिएका नेटवर्क प्रविधिमा निर्भर छ।
Interconnected Nepal: Bridging distance with digital signals.
2. Telecommunication / दूरसञ्चार
Tele + Communication
Derived from the Greek word 'Tele' (meaning distant or far off) and Latin 'Communicare' (to share). It is the exchange of information over significant distances by electronic or electromagnetic means.
ग्रीक शब्द 'Tele' (जसको अर्थ टाढा हुन्छ) र ल्याटिन शब्द 'Communicare' (साझेदारी गर्नु) बाट बनेको हो। इलेक्ट्रोनिक वा इलेक्ट्रोम्याग्नेटिक माध्यमबाट टाढा-टाढा सूचना आदानप्रदान गर्ने प्रविधिलाई दूरसञ्चार भनिन्छ।
Examples in Everyday Life / प्रमुख उदाहरणहरू
3. Data Communication System / डाटा सञ्चार प्रणाली
4. Transmission Media / प्रसारण माध्यम
Guided Media (Wired / तारयुक्त)
Physical solid cables that carry data signals along a contained path.
भौतिक तारहरू जसले निश्चित मार्गबाट डाटा सङ्केतहरू लैजान्छन्।
Used in LANs & landline telephones. Inexpensive, easy to install.
Used in Cable TV networks in Nepal. Good shielding against interference.
Uses total internal reflection of light. Highest speed (FTTH internet in Nepal like WorldLink, NT Fiber).
Unguided Media (Wireless / ताररहित)
Electromagnetic waves transmitted through air, space, or water.
हावा वा अन्तरिक्ष मार्फत प्रसारण हुने इलेक्ट्रोम्याग्नेटिक तरङ्गहरू।
Omnidirectional (FM radio, Wi-Fi, 4G/5G mobile networks).
Line-of-sight propagation (dish antennas on mobile towers).
Infrared for TV remotes; Satellites for long-distance global broadcasts.
5. Computer Network / कम्प्युटर नेटवर्क
Formal Definition / परिभाषा
A computer network is an interconnected group of autonomous computers and computing devices connected via transmission media to share resources (files, printers) and communicate.
कम्प्युटर नेटवर्क भनेको आपसमा जोडिएका स्वतन्त्र कम्प्युटर र उपकरणहरूको समूह हो, जसले डाटा, सूचना तथा स्रोतहरू (जस्तै: प्रिन्टर, इन्टरनेट) साझा गर्न सक्छन्।
Key Benefits / मुख्य फाइदाहरू:
- Hardware Sharing (One printer for whole lab)
- Software & File Sharing
- Centralized Data Storage & Backup
- Instant Communication (Email, Chat)
Both PC-1 and PC-2 can print documents over the local network.
6. Types of Networks / नेटवर्कका प्रकारहरू
7. Network Devices / नेटवर्क उपकरणहरू
8. Network Topologies / नेटवर्क टोपोलोजीहरू
9. Network Architecture / नेटवर्क संरचना
1. Client-Server Architecture
A centralized system where powerful computers (Servers) store files and respond to requests from user workstations (Clients).
केन्द्रीकृत प्रणाली जहाँ शक्तिशाली कम्प्युटर (सर्भर) ले डाटा भण्डारण गर्छ र क्लाइन्ट कम्प्युटरको अनुरोध पूरा गर्छ।
2. Peer-to-Peer (P2P) Architecture
All computers on the network have equal capabilities and responsibilities. There is no dedicated central server.
सबै कम्प्युटरहरूको समान क्षमता र अधिकार हुन्छ। यहाँ कुनै छुट्टै मुख्य सर्भर हुँदैन।
10. Internet, Intranet & Extranet
| Feature | Internet (इन्टरनेट) | Intranet (इन्ट्रानेट) | Extranet (एक्स्ट्रानेट) |
|---|---|---|---|
| Access Level | Public global network | Private to organization employees | Private with trusted vendor/partner access |
| Example in Nepal | Browsing Wikipedia, Google | Internal portal of Nepal Bank Ltd. | Supplier portal of CG Group or Ncell |
| Security | Low / Public threat exposure | High security behind firewalls | Controlled authentication (VPNs) |
11. Network Protocols / सञ्चार नियमावली
Transmission Control Protocol / Internet Protocol. The fundamental rules governing the global Internet.
Hypertext Transfer Protocol (Secure). Used for fetching web pages securely with SSL encryption.
File Transfer Protocol. Specialized rules for uploading and downloading large files between devices.
Domain Name System. Translates human-friendly names (e.g., google.com) into IP addresses (142.250.x.x).
12. Advantages & Disadvantages / फाइदा तथा बेफाइदाहरू
Advantages (फाइदाहरू)
- Resource Sharing: Share expensive printers, scanners & storage.
- Fast Communication: Instant emails, voice calls & videoconferencing.
- Centralized Data: Data saved centrally for easier backups.
- Cost Efficiency: Reduces paper, printing, and hardware expenses.
Disadvantages (बेफाइदाहरू)
- Security Risks: Viruses, malware, and hacking threats.
- Server Dependency: Main server failure halts whole network.
- Setup Cost: High initial investment for cables, switches, routers.
- Maintenance: Requires skilled network administrators.