✅What is a Computer Network?

A computer network is a collection of two or more computers (or devices like printers, servers, switches, routers) that are connected together to share resources (files, applications, printers), communicate, or access the internet.

Example: Your home Wi-Fi is a small computer network.

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✅ Types of Networks

Networks are classified mainly by size/area covered:

1. LAN (Local Area Network)
   • Covers small area (office, home, school).
   • High speed, low cost.
   • Example: Office network with 10 PCs and a printer.
2. WAN (Wide Area Network)
   • Covers large geographical area (countries, worldwide).
   • Internet is the largest WAN.
   • Example: Bank ATMs connected nationwide.
3. MAN (Metropolitan Area Network)
   • Covers a city or large campus.
   • Example: Cable TV network, city-wide Wi-Fi.
4. PAN (Personal Area Network)
   • Very small range, usually within a few meters.
   • Example: Bluetooth between phone and headphones.

👉 Other categories: CAN (Campus Area Network), SAN (Storage Area Network), VPN (Virtual Private Network).

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✅ Uses of Networks

• Resource Sharing – printers, files, applications.
• Communication – email, chat, video calls.
• Centralized Data Management – store & secure data in servers.
• Scalability – add users without much cost.
• Internet Access Sharing – one internet line for many users.

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✅ Domain vs Workgroup

🔹 Workgroup

• Peer-to-peer network (no central control).
• Each computer manages its own settings and logins.
• Good for small networks (≤10 PCs) like home or small office.
• Example: You can share files between two laptops at home using a workgroup.

🔹 Domain

• Client–Server model (centralized control).
• Managed by a server (Domain Controller – DC).
• Centralized authentication (same username/password works on all PCs).
• Good for large organizations (hundreds of computers).
• Example: In an office, you log into your PC using your company credentials (Windows Active Directory domain).

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👉 In short:

• Workgroup = Simple, decentralized, for small networks.
• Domain = Centralized, secure, scalable, for enterprise.