Computer Networks Overview

Computer Networks

• Definition: A computer network is a collection of computers and devices interconnected to share resources and communicate.

• Types of Networks:

  • LAN (Local Area Network):
    • Small geographic area (e.g., home, office).
    • High-speed connectivity.
  • WAN (Wide Area Network):
    • Covers large geographic areas (e.g., cities, countries).
    • Slower compared to LAN; often uses leased telecommunication lines.
  • MAN (Metropolitan Area Network):
    • Connects networks within a specific metropolitan area.
    • Larger than LAN but smaller than WAN.
  • PAN (Personal Area Network):
    • Very short range, typically within a few meters (e.g., Bluetooth devices).

• Network Topologies:

  • Star: Central node with connected devices; easy to manage but vulnerable to central node failure.
  • Bus: All devices share a single communication line; easy to set up but limited by cable length and traffic.
  • Ring: Each device connected to two others, forming a circle; data travels in one direction.
  • Mesh: Each device connects to multiple others; highly reliable but expensive to set up.

• Protocols:

  • TCP/IP (Transmission Control Protocol/Internet Protocol): Foundation of internet communication; breaks data into packets for transmission.
  • HTTP/HTTPS (Hypertext Transfer Protocol / Secure): Used for transferring web pages; HTTPS provides encryption.
  • FTP (File Transfer Protocol): Protocol for transferring files between computers.
  • SMTP (Simple Mail Transfer Protocol): Protocol for sending emails.

• Network Devices:

  • Router: Directs data packets between networks; connects different networks.
  • Switch: Connects devices within a LAN; manages data traffic efficiently.
  • Modem: Modulates and demodulates signals for internet access; connects home networks to the ISP.
  • Access Point: Extends wireless network connectivity to devices.

• IP Addressing:

  • IPv4: 32-bit address format; provides ~4.3 billion addresses.
  • IPv6: 128-bit address format; designed to replace IPv4 and accommodate more devices.

• Network Security:

  • Firewalls: Monitors and controls incoming/outgoing network traffic.
  • Antivirus Software: Protects devices from malware and viruses.
  • Encryption: Secures data transmission over networks.

• Applications of Computer Networks:

  • File sharing and collaboration tools.
  • Streaming services (audio, video).
  • Online gaming and social media platforms.
  • Cloud computing services for storage and processing.

• Emerging Technologies:

  • IoT (Internet of Things): Interconnected devices for data sharing (e.g., smart home devices).
  • 5G Networks: Next generation mobile networks offering faster data speeds and increased capacity.

Computer Networks Definition

• A computer network is a group of interconnected computers and devices that share resources and communicate.

Network Types

• LAN (Local Area Network): Covers small areas like homes or offices, offering high-speed connectivity
• WAN (Wide Area Network): Spans large geographic areas like cities or countries, using leased telecommunication lines for slower connectivity compared to LANs
• MAN (Metropolitan Area Network): Connects networks within a city or metropolitan area, larger than LANs but smaller than WANs
• PAN (Personal Area Network): Covers very short ranges, typically within a few meters, used for devices like Bluetooth connections

Network Topologies

• Star Topology: Features a central node with connected devices, offering easy management but vulnerability to central node failure
• Bus Topology: Uses a single shared communication line for all devices, easy to set up but limited by cable length and traffic congestion
• Ring Topology: Each device connects to two others, forming a circular network, data travels in one direction
• Mesh Topology: Every device connects to multiple others, highly reliable but expensive to set up

Network Protocols

• TCP/IP (Transmission Control Protocol/Internet Protocol): Forms the foundation of internet communication, breaking data into packets for transmission
• HTTP/HTTPS (Hypertext Transfer Protocol / Secure): Used for transferring web pages, HTTPS provides encryption for security
• FTP (File Transfer Protocol): Used for transferring files between computers
• SMTP (Simple Mail Transfer Protocol): Used for sending emails

Network Devices

• Router: Directs data packets between networks, connecting different networks
• Switch: Connects devices within a LAN, managing data traffic efficiently
• Modem: Modulates and demodulates signals for internet access, connecting home networks to the ISP
• Access Point: Extends wireless network connectivity to devices

IP Addressing

• IPv4: Uses a 32-bit address format, offering approximately 4.3 billion addresses
• IPv6: Uses a 128-bit address format, designed to replace IPv4, allowing for a much larger number of addresses

Network Security

• Firewalls: Monitors and controls incoming and outgoing network traffic
• Antivirus Software: Protects devices from malware and viruses
• Encryption: Secures data transmission over networks

Applications of Computer Networks

• Enable file sharing and collaboration tools
• Power streaming services for audio and video content
• Support online gaming and social media platforms
• Facilitate cloud computing services for storage and processing

Emerging Technologies

• IoT (Internet of Things): Connects devices to share data, enabling applications like smart home devices
• 5G Networks: Next generation mobile networks offering faster data speeds and increased capacity