Computer Networks and Internet Basics – Class 10 Computer Science

Computer Networks and Internet Basics

A computer network is a group of interconnected computers and devices that can share data, resources, and information with each other.

Types of Networks

Type	Full Form	Coverage	Example
PAN	Personal Area Network	~10 metres	Bluetooth headphones connected to phone
LAN	Local Area Network	Building / campus	School computer lab, office network
MAN	Metropolitan Area Network	City	Cable TV network, city-wide Wi-Fi
WAN	Wide Area Network	Countries / global	The Internet itself

Network Devices

• Modem: Converts digital signals to analogue (modulation) and vice versa (demodulation) for transmission over telephone lines.
• Hub: Broadcasts data to all connected devices (no intelligence).
• Switch: Sends data only to the intended device (smarter than hub).
• Router: Connects different networks and routes data packets using IP addresses. Your home Wi-Fi router connects your LAN to the WAN (Internet).
• Gateway: Connects two networks with different protocols.

The Internet

The Internet is a global WAN — a "network of networks." Key concepts:

• IP Address: A unique numerical label assigned to every device (e.g., 192.168.1.1). IPv4 uses 32 bits; IPv6 uses 128 bits.
• URL: Uniform Resource Locator — the address of a webpage (e.g., https://sixbytes.in).
• DNS: Domain Name System — converts domain names (sixbytes.in) to IP addresses.
• HTTP/HTTPS: Protocols for transferring web pages. HTTPS adds encryption (SSL/TLS) for security.

Web Technologies

• HTML: HyperText Markup Language — structures web page content.
• CSS: Cascading Style Sheets — styles the appearance of web pages.
• JavaScript: Adds interactivity to web pages.
• Web Browser: Software that renders web pages (Chrome, Firefox, Edge).
• Web Server: A computer that stores and serves web pages to browsers.

Cyber Safety and Ethics

• Cyber Crime: Illegal activities using computers — hacking, phishing, identity theft, cyberbullying.
• Phishing: Fake emails or websites designed to steal personal information.
• Strong Passwords: Use 8+ characters with uppercase, lowercase, numbers, and symbols. Never share passwords.
• Malware: Malicious software — viruses, worms, trojans, ransomware. Use antivirus software and keep systems updated.
• Digital Footprint: The trail of data you leave online. Be mindful of what you share on social media.
• Intellectual Property: Respect copyright, use Creative Commons content, and cite sources properly.

Reference: NCERT Computer Science Textbook for Class 10; Sumita Arora's Informatics Practices; CBSE Study Material.