Computer Networks Overview

Study Notes

A computer network is a group of interconnected computers and devices that communicate to share resources and data.
The purpose of computer networks is to facilitate data exchange and communication, and enable resource sharing (e.g., printers, files, internet).

Local Area Network (LAN): Connects computers within a small area, like an office, typically private.
Wide Area Network (WAN): Covers a large geographic area (e.g., cities, countries) using leased telecom lines; the internet is the largest WAN.
Metropolitan Area Network (MAN): Connects networks within a city, often used by businesses or government.

Router: Directs data between networks, enabling internet access.
Switch: Connects devices within a network and 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.

The internet is a vast network connecting millions of private, public, academic, and business networks globally.
It originated from ARPANET in the 1960s, becoming commercialized in the 1990s.
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 (e.g., google.com) into IP addresses.
IPv4: A 32-bit address, now limited in availability. Comprised of four octets separated by periods, each octet ranging from 0 to 255.
IPv6: A 128-bit address designed to accommodate the expanded number of internet-connected devices. Represented by 8 groups of 4 hexadecimal characters.

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.

Network security is crucial to protect data and resources from cyber 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 firewalls, antivirus software, encryption, and two-factor authentication (2FA).

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