Computer Networks Overview

Computer Networks

• 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.
• They enable resource sharing of items like printers, files, and internet connections.

Types of Computer Networks

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

Networking Devices

• 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 to analog signals for transmission over phone lines.
• Access Point: Provides wireless connectivity within a network.
• Firewall: A security device that controls network traffic to prevent unauthorized access.

Introduction to the Internet

• The internet is a vast network connecting millions of private, public, academic, and business networks globally.
• It originated from ARPANET in the 1960s and became commercialized in the 1990s.
• Data is broken into packets and transmitted over networks, then reassembled on arrival.

Internet Protocols

• Internet Protocol (IP): Manages addressing and routing of packets across networks.
• Transmission Control Protocol (TCP): Ensures reliable delivery of packets across networks.
• 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 emails.

IP Addresses and Domain Names

• 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: 32-bit address, limited in availability, uses four octets separated by periods.
• IPv6: 128-bit address, created to handle the expansion of internet-connected devices, uses hexadecimal characters.

Internet Services and Applications

• World Wide Web (WWW): A collection of websites and web pages accessible via the internet.
• Email: Digital communication via 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.

Cybersecurity in Networking

• Network Security: Protects 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 and demands a ransom.
• DDoS: Overloads servers with traffic, causing a shutdown.
• Security Measures: Use of firewalls, antivirus software, encryption, and two-factor authentication (2FA).