Computer Networks Overview

Study Notes

A computer network is a group of interconnected computers and devices that communicate to share resources and data.
Purpose: Facilitate data exchange and communication, enable resource sharing (e.g., printers, files, internet).
Examples:
- Local Area Network (LAN): Within a single building.
- Wide Area Network (WAN): Across large areas (cities, countries).
- Metropolitan Area Network (MAN): Covers a city or campus area.

Local Area Network (LAN): Connects computers within a small area, like an office, typically private.
Metropolitan Area Network (MAN): Connects networks within a city, often used by businesses or government.
Wide Area Network (WAN): Covers a large geographic area, using leased telecom lines; the internet is the largest WAN.
Wireless Networks: Include Wi-Fi and Bluetooth; essential for mobile connectivity.

Router: Directs data between networks, enabling internet access.
Switch: Connects devices within a network; filters data to the correct destination.
Modem: Converts digital data for transmission over phone lines.
Access Point: Provides wireless connectivity within a network.
Firewall: Security device that controls network traffic to prevent unauthorized access.

Internet Definition: A vast network connecting millions of private, public, academic, and business networks globally.
Brief History: Originated from ARPANET in the 1960s; became commercialized in the 1990s.
How It Works: Data is broken into packets, transmitted over networks, and reassembled on arrival.

Internet Protocol (IP): Manages addressing and routing of packets across networks.
Transmission Control Protocol (TCP): Ensures reliable delivery of packets.
Hypertext Transfer Protocol (HTTP/HTTPS): Governs web communication and security (HTTPS).
File Transfer Protocol (FTP): Used for transferring files over the internet.
Email Protocols (SMTP, POP3, IMAP): Manage sending and receiving email.

IP Address: A unique identifier assigned to each device on a network (e.g., 192.168.1.1).
Domain Name System (DNS): Translates human-friendly domain names into IP addresses.
IPv4: 32-bit address, limited in availability; Example: 192.168.0.1
IPv6: 128-bit address, created to handle the expansion of internet-connected devices; Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334

World Wide Web (WWW): A collection of websites and web pages accessible via the internet.
Email: Digital communication through electronic mail services.
Cloud Computing: Accessing and storing data online rather than locally.
Social Media and Streaming Services: Platforms for interaction, entertainment, and sharing content.

Importance of Network Security: Protects data and resources from cyber threats.
Common Threats:
- Malware: Malicious software designed to damage or exploit devices.
- Phishing: Fraudulent attempts to gather sensitive information.
- Ransomware: Malware that encrypts data, demanding a ransom.
- DDoS: Overloads servers with traffic, causing a shutdown.
Security Measures: Use of firewalls, antivirus software, encryption, and two-factor authentication (2FA).

5G and Beyond: Next-generation cellular networks enabling faster data transmission.
Internet of Things (IoT): Network connectivity extending to everyday objects, allowing data exchange.
Artificial Intelligence in Networking: Al improves network efficiency, security, and troubleshooting.
Quantum Networking: Future technology for highly secure communication using quantum mechanics.