Computer science Topic 1.3 Network

• Network


  A collection of interconnected computers and devices that can share resources and communicate with each other
• Types of Networks


  • Local Area Network (LAN)
  • Wide Area Network (WAN)
  • Metropolitan Area Network (MAN)
• Local Area Network (LAN)


  • Connects devices in a limited geographical area, typically a home, school, or office building
  • Private networks with high speeds and reliability
• Wide Area Network (WAN)


  • Spans a larger geographical distance, often connecting LANs across cities, countries, or even continents
  • May use various communication technologies like leased lines, satellites, or the internet
• Metropolitan Area Network (MAN)


  • Covers a larger area than a LAN but smaller than a WAN, typically encompassing a city or town
  • Often used to connect different LANs within a specific region
• Network Connections


  • Wired Connections
  • Wireless Connections
• Wired Connections


  • Rely on physical cables like ethernet, coaxial, or fiber optic cables to transmit data between devices
  • Offer high speeds and reliability but can be less flexible in terms of mobility
• Wireless Connections


  • Use radio waves to transmit data through the air
  • Common wireless technologies include Wi-Fi, Bluetooth, and cellular networks
  • Provide greater mobility but may experience interference or limitations in signal strength and speed
• Network Topology


  The physical or logical layout of how devices are arranged in a network
• Network Topologies


  • Bus Topology
  • Star Topology
  • Mesh Topology
• Bus Topology


  • All devices are connected to a single central cable
  • Data travels from one device to all others on the network
  • Simple and inexpensive setup but can be prone to failures if the central cable malfunctions
• Star Topology


  • Each device has its own dedicated connection to a central hub or switch
  • Offers better performance and fault tolerance compared to a bus network
  • A failure in one device won't affect others
• Mesh Topology


  • Devices are interconnected with each other, creating multiple pathways for data transmission
  • Provides high redundancy and fault tolerance but can be more complex to set up and manage
• Network Protocols


  Sets of rules that govern how data is formatted, transmitted, and received over a network
• Essential Network Protocols


  • TCP/IP (Transmission Control Protocol/Internet Protocol)
  • HTTP (Hypertext Transfer Protocol)
  • HTTPS (Hypertext Transfer Protocol Secure)
• TCP/IP


  • The foundation of internet communication
  • TCP is responsible for breaking down data into packets, ensuring reliable delivery, and error correction
  • IP handles addressing and routing packets across networks
• HTTP


  • Used for communication between web browsers and web servers
  • Defines how web pages and their content are formatted and transmitted over the internet
• HTTPS


  A secure version of HTTP that encrypts data transmission between web browsers and web servers, protecting sensitive information from eavesdropping
• Network Devices


  • Network Interface Card (NIC)
  • Switch
  • Router
  • Hub
• Network Interface Card (NIC)


  • Allows a computer to connect to a network
  • Translates data from the computer into electrical signals that can travel on the network cable
• Switch


  • An intelligent device that connects multiple devices on a network and forwards data packets to the intended recipient
  • Learns the MAC addresses of connected devices and improves network efficiency by directing traffic only to the specific device
• Router


  • Connects multiple networks and directs data packets between them based on their destination IP addresses
  • Acts as a traffic director, ensuring data reaches its intended destination across different networks
  • Can also perform Network Address Translation (NAT) for private networks
• Hub


  • A simpler device that broadcasts data packets to all devices connected to it
  • While less expensive than switches, hubs can lead to network congestion as all devices receive all data packets
• Network Security


  Protecting data and devices from unauthorized access, malicious attacks, and other threats
• Key Network Security Concepts

  • Firewalls
  • Encryption
• Firewalls


  • Act as security barriers that filter incoming and outgoing traffic based on predefined rules
  • Can help block unauthorized access and malicious software
• Encryption


  Scrambles data using a secret key, making it unreadable to anyone who doesn't have the key