Networking 1: Week 1 Introduction

Introduction to Computer Networks

• Data communication refers to the transmission of data between devices, while networks enable interaction among various devices through connections like wires or optical fibers.

Definition of Computer Network

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

Classification of Computer Networks

• Geographical Span:

  • Networks can range from personal area networks (PAN) to wide area networks (WAN), covering distances from meters to the entire globe.

• Inter-Connectivity:

  • Connections can be mesh (each device connected to every other), bus (central medium with dispersed connections), linear (devices connected sequentially), star (all devices connected to a central point), or hybrid (combination of structures).

• Administration:

  • Networks can be private, limited to a single entity, or public, accessible by everyone.

• Network Architecture:

  • Architectural types include client-server (where servers provide resources to clients) and peer-to-peer (all devices have equal responsibilities).

Components of a Computer Network

• NIC (Network Interface Card):

  • Essential for device communication, available in wireless (using antennas and radio waves) and wired forms (using cables).

• Hub:

  • Central device that distributes requests to connected devices without filtering the traffic.

• Switch:

  • More intelligent than a hub, it sends messages specifically to the intended device rather than broadcasting.

• Cables and Connectors:

  • Types of cables include twisted pair (high-speed data transfer), coaxial (commonly used for TV), and fiber optic (transmits data as light for high-speed connections).

• Router:

  • Connects local area networks (LAN) to the internet, managing data traffic between different networks.

• Modem:

  • Facilitates internet access over telephone lines and operates separately from the computer's motherboard.

Uses of Computer Networks

• Resource Sharing:

  • Enables sharing of programs, printers, and data without requiring physical proximity.

• Server-Client Model:

  • Centralized server manages data storage for client machines that access resources remotely.

• Communication:

  • Functions as a medium for communication among users using email systems and other tools.

• E-commerce:

  • Supports online business operations, exemplified by platforms like Amazon.

Features of Computer Networks

• Communication Speed:

  • Facilitates fast communication like video conferencing and instant messaging.

• File Sharing:

  • Allows users to share files easily.

• Backup and Recovery:

  • Simplified backup processes due to centralized storage.

• Software and Hardware Sharing:

  • Central installation of applications reduces redundancy and installation efforts on individual machines.

• Security:

  • Controls access to sensitive files and applications.

• Reliability:

  • Provides alternative data communication routes to maintain functionality during hardware outages.

• Scalability:

  • Capability to add new devices without significantly degrading performance, although this can introduce errors.

Computer Network Architecture

• Physical and logical designs comprising software, hardware, protocols, and media involved in data transmission.
• Two main types:

  • Peer-To-Peer Networks: All computers hold equal status; advantageous for small setups (up to 10 computers), less expensive and easier to maintain but lacks centralized control for data security and backup.

  • Client/Server Networks: Centralized architecture with a server managing resources, improving security and backup capabilities; however, more costly due to server and NOS requirements.

Advantages and Disadvantages

• Peer-To-Peer Network:

  • Advantages: Cost-effective, robust against individual computer failures, simple setup.
  • Disadvantages: Lack of centralized data management and security risks.

• Client/Server Network:

  • Advantages: Centralized data management, better security, enhanced performance.
  • Disadvantages: Higher costs for servers and operating systems, need for a dedicated network administrator.