Computer Communication and Networks Summary

Introduction to Computer Network

A computer network is defined as two or more computers connected to communicate data electronically and share resources such as printers, hard disks, and scanners through either physical cables or wireless connections. Networks can be located within the same room, building, or spread across different locations, making them vital for businesses, educational institutions, and individual users to retrieve and share information effectively.

Uses of Computer Network

Computer networks serve multiple purposes including:

  • Communication
  • Resource Sharing
  • Remote Access
  • Collaboration
  • E-commerce
  • Education
  • Entertainment

Applications of Computer Network

Business Applications

Used by businesses for communication, resource sharing, and remote access to systems.

Home Applications

Includes Wi-Fi, Bluetooth, smart devices (e.g., smart thermostats, refrigerators), and future technologies like 5G.

Mobile Applications

Mobile users depend on cellular networks (2G, 3G, 4G, 5G) for connectivity.

Social Issues Associated

Such as privacy concerns, cybercrime, and the digital divide.

Network Criteria

Key factors for evaluating a network include:

  • Performance: Measured by transmit and response times, throughput, and delay.
  • Reliability: Assessed by data accuracy and failure rates.
  • Security: Protects against unauthorized access and viruses.

Data Communication

Data communication is the electronic transfer of data, which can be local or remote. It encompasses raw facts including text, graphics, sound, and video.

Characteristics of Data Communication

Essential characteristics include delivery to the correct destination, accuracy, and timeliness (real-time delivery).

Basic Elements of Data Communication

  1. Message: The information to be communicated (text, audio, video, etc.).
  2. Sender: The initiating device (computers, smartphones).
  3. Receiver: The device or person for receiving messages (computers, printers).
  4. Transmission Medium: The channel through which messages are transmitted (wired/wireless).
  5. Protocol: Defines rules for communication.
  6. Encoding/Decoding: Converts data for transmission and back.
  7. Transmission Modes: Determines data flow direction (simplex, half-duplex, full-duplex).
  8. Topology: Physical arrangement of devices.
  9. Timing: Synchronization during communication.

Types of Network Connections

  1. Point-to-Point: A dedicated link between two devices.
  2. Multipoint: More than two devices share a connection.

Examples of Data Communication in Daily Life

  • Emails
  • Instant Messaging
  • Video Conferencing
  • File Transfers (FTP)
  • Web Browsing (HTTP)
  • VoIP
  • Social Media
  • IoT Devices
  • GPS Systems
  • Cloud Computing