Computer Networks PDF

INTRODUCTION TO COMPUTER NETWORKS Computer Network Definition: A computer network is a group of interconnected computers and devices that communicate to share resources and data. Purpose of Computer Networks: - Facilitate data exchange and communication. - Enable resource sharing, like printers, fi...

INTRODUCTION TO COMPUTER NETWORKS Computer Network Definition: A computer network is a group of interconnected computers and devices that communicate to share resources and data. Purpose of Computer Networks: - Facilitate data exchange and communication. - Enable resource sharing, like printers, files, and internet connections. Examples: - Local Area Network (LAN): Within a single building. - Wide Area Network (WAN): Across large areas, such as cities or countries. - Metropolitan Area Network (MAN): Covers a city or campus area. TYPES OF COMPUTER NETWORKS 1. Local Area Network (LAN): Connects computers within a small area like an office; typically private. TYPES OF COMPUTER NETWORKS 1. Metropolitan Area Network (MAN): Connects networks within a city; often used by businesses or government. TYPES OF COMPUTER NETWORKS 1. Wide Area Network (WAN): Covers a large geographic area, using leased telecom lines; the internet is the largest WAN. TYPES OF COMPUTER NETWORKS Wireless Networks: Examples include Wi-Fi and Bluetooth; essential for mobile connectivity. NETWORKING DEVICES 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. Router Switch Modem Access Point Firewall INTRODUCTION TO THE INTERNET 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 PROTOCOLS 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 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 (like google.com) into IP addresses. IPv4 vs IPv6: - IPv4: 32-bit address, now limited in availability. Example: 192.168.0.1 composed of four octets (8 digits) separated by periods, with each octet being a number from 0 to 255. - IPv6: 128-bit address, created to handle the expansion of internet-connected devices. Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334 128 bits, represented by 8 groups of 4 hexadecimal characters (16 bits each). INTERNET SERVICES AND APPLICATIONS 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. CYBERSECURITY IN NETWORKING 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).