Summary of Computer Networks and Internet Fundamentals
Computer Networks & Internet Fundamentals: Student Guide
Introduction
Computer networking connects computers and devices so they can share data, hardware (like printers) and services (like file storage). This study material explains the main network types, key network devices, communication media, and basic network software in clear, student-friendly sections with examples and practical uses.
Definition: A network is a group of two or more interconnected devices that can share data, resources and services.
1. Network Types (by size and purpose)
Breakdown of common network types and where you might see them.
1.1 Personal Area Network (PAN)
- Covers a very short range (about 10 meters).
- Typical devices: smartphone, laptop, smartwatch, wireless earphones.
- Usually wireless (Bluetooth or Wi‑Fi), but can be wired.
Definition: A PAN connects personal devices close to one person, often using Bluetooth or Wi‑Fi.
Practical example: Connecting your phone to a smartwatch and wireless earbuds while walking.
1.2 Home Area Network (HAN)
- Connects all devices inside a home using a router.
- Devices can be wired or wireless.
Practical example: A smart TV, laptop and smartphone all using the same home router to access the Internet and stream video.
1.3 Local Area Network (LAN)
- Connects devices in a limited area (room, school, office).
- Can be wired (Ethernet) or wireless (WLAN).
Practical example: A school computer lab where all computers access a shared printer and file server.
1.4 Metropolitan Area Network (MAN)
- Connects multiple LANs across a city or large area using high-speed links.
Practical example: A city library system linking branches across the metropolitan area.
1.5 Wide Area Network (WAN)
- Connects LANs and MANs across cities or countries.
Practical example: A company linking its offices in Johannesburg and Cape Town.
1.6 Global Area Network (GAN)
- A worldwide network, the best example being the Internet.
Definition: A GAN is a network that spans the globe by interconnecting multiple WANs.
2. Advantages and Disadvantages of Networks
Advantages
- Resource sharing: Printers, file servers and Internet connections can be shared to save costs.
- Communication: Email, instant messaging and video calls allow fast communication.
- Collaboration: Multiple users can access and edit the same file stored on a server without creating duplicate copies.
Disadvantages
- Cost: Initial setup for cabling, switches and servers can be expensive.
- Management: Networks often need skilled staff to configure and maintain them.
- Security risks: Viruses and hackers can spread across a network if not protected.
- Outages: If the network fails, services and access can be lost until repaired.
💡 Věděli jste?Did you know that a single infected device can spread malware across a network if proper security controls are not in place?
3. Network Devices (what they do and examples)
Use this table to compare common hardware used in networks.
| Device | Main function | Typical location | Example use |
|---|---|---|---|
| Network Interface Card (NIC) | Connects a device to a wired network via a cable port | Inside a PC or server | Desktop computer plugged into an Ethernet cable |
| Switch | Connects multiple wired devices within a LAN and forwards data between them | Network rack or office closet | Connects workstations and a file server in an office |
| Router | Connects a LAN to other networks (often the Internet) and assigns IP addresses | Home or office edge device | Home router connecting devices to an ISP |
| Wireless Access Point (WAP) | Provides wireless connectivity to a wired network | Ceiling or wall in offices, homes | Allows laptops and phones to join a wired network wirelessly |
| Modem / Fibre ONT | Converts ISP signal (DSL, cable, fibre) to a local network signal | At building entry point | Fi |
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Computer Networking Basics
Klíčové pojmy: A network connects devices to share resources and services, PAN covers personal devices within ~10 m; often Bluetooth or Wi‑Fi, HAN connects home devices via a router; wired or wireless, LAN links devices in a limited area; often uses switches and servers, MAN links LANs across a city; WAN connects networks across regions or countries, Switches forward data between devices in a LAN and reduce unnecessary traffic, Routers connect different networks and often provide NAT and basic firewalling, WAPs provide wireless access but must be cabled to the network, NIC is the hardware interface that connects a device to a wired network, Fibre provides high-speed long-distance links; copper Ethernet is common for LANs, SIM routers use cellular networks to provide Internet when fixed lines are unavailable, Network software manages access, security and services like DHCP