plus one computer applications notes

HSSLIVE Plus One Computer Application Chapter 8: Computer Networks Notes

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Computer networks enable communication and resource sharing between computing devices. This chapter introduces network architectures, topologies (bus, star, ring, mesh), and classification by scale (LAN, MAN, WAN). Students will explore network protocols, the OSI and TCP/IP models, addressing schemes, and routing methods. The chapter also covers network hardware components such as routers, switches, and access points, and concepts like bandwidth and latency.

Chapter 8: Computer Networks

Introduction to Computer Networks

A computer network is a collection of computers and other devices that are connected together to share resources and communicate with each other. Networks enable data sharing, resource utilization, and communication among connected devices.

Network Components

  1. Hardware Components:
    • Network Interface Card (NIC): Enables computers to connect to a network
    • Hub: Connects multiple devices in a network, broadcasts data to all connected devices
    • Switch: Intelligent device that forwards data only to the intended recipient
    • Router: Connects different networks and routes data between them
    • Modem: Converts digital signals to analog (and vice versa) for transmission over telephone lines
    • Repeater: Amplifies signals to extend network range
    • Bridge: Connects similar network segments and filters traffic
    • Gateway: Connects dissimilar networks
  2. Software Components:
    • Network Operating System (NOS): Manages network resources
    • Protocols: Rules governing communication between devices
    • Drivers: Software that allows hardware to communicate with the OS
  3. Transmission Media:
    • Wired Media:
      • Twisted Pair Cable: Common in Ethernet networks (UTP, STP)
      • Coaxial Cable: Used in cable TV networks and older Ethernet
      • Fiber Optic Cable: Uses light for high-speed, long-distance transmission
    • Wireless Media:
      • Radio Waves: Used in Wi-Fi networks
      • Microwaves: Used for long-distance communication
      • Infrared: Short-range, line-of-sight communication
      • Satellite: Global communication via orbiting satellites

Network Types Based on Scale

  1. Personal Area Network (PAN): Very small network around an individual (range ~10 meters)
    • Examples: Bluetooth connections between phone, headset, and laptop
  1. Local Area Network (LAN): Network covering a small geographical area like a home, office, or school
    • Limited to a few kilometers
    • Higher data transfer rates
    • Examples: Office networks, school computer labs
  2. Metropolitan Area Network (MAN): Network spanning a city or large campus
    • Covers up to tens of kilometers
    • Often connects multiple LANs
    • Examples: Cable TV networks, city-wide networks
  3. Wide Area Network (WAN): Network spanning large geographical areas, countries, or continents
    • Unlimited geographical area
    • Often uses public communication infrastructure
    • Example: The Internet
  4. Storage Area Network (SAN): Specialized high-speed network for storage devices
    • Provides block-level storage access
    • Used in enterprise environments

Network Topologies

The physical or logical arrangement of computers and devices in a network:

  1. Bus Topology:
    • All devices connected to a single central cable (backbone)
    • Advantages: Simple, inexpensive, easy to extend
    • Disadvantages: Limited cable length, entire network affected by cable failure
  2. Star Topology:
    • All devices connected to a central hub or switch
    • Advantages: Easy to install, fault isolation, easy to detect problems
    • Disadvantages: Depends on central device, requires more cable
  3. Ring Topology:
    • Devices connected in a closed loop
    • Advantages: Equal access for all devices, performs well under heavy load
    • Disadvantages: Difficult to add devices, single point of failure affects all
  4. Mesh Topology:
    • Every device connected directly to every other device
    • Advantages: High redundancy, no traffic bottlenecks
    • Disadvantages: Expensive, difficult to implement, high cable requirement
  5. Tree/Hierarchical Topology:
    • Combination of bus and star topologies
    • Advantages: Scalable, easy to manage
    • Disadvantages: Depends on root, can be expensive
  6. Hybrid Topology:
    • Combination of two or more topologies
    • Advantages: Flexible, reliable
    • Disadvantages: Complex to design and implement

Network Architecture

  1. Client-Server Model:
    • Dedicated servers provide services to client computers
    • Centralized resource management
    • Examples: Web servers, email servers, file servers
  2. Peer-to-Peer (P2P) Model:
    • All computers function as both clients and servers
    • No central management
    • Examples: File sharing networks, cryptocurrency networks

Network Protocols

Protocols are standardized rules that allow devices to communicate with each other. Key protocols include:

  1. TCP/IP (Transmission Control Protocol/Internet Protocol):
    • Foundation protocol suite for the Internet
    • Layers:
      • Application Layer: HTTP, FTP, SMTP, DNS
      • Transport Layer: TCP, UDP
      • Internet Layer: IP, ICMP
      • Network Interface Layer: Ethernet, Wi-Fi
  2. HTTP/HTTPS (Hypertext Transfer Protocol):
    • Used for web browsing
    • HTTPS is the secure version using encryption
  3. FTP (File Transfer Protocol):
    • Used for transferring files between computers
  4. SMTP (Simple Mail Transfer Protocol):
    • Used for sending email
  5. POP3/IMAP (Post Office Protocol/Internet Message Access Protocol):
    • Used for receiving email
  6. DNS (Domain Name System):
    • Translates domain names to IP addresses

IP Addressing

IP addresses uniquely identify devices on a network:

  1. IPv4 (Internet Protocol version 4):
    • 32-bit address (e.g., 192.168.1.1)
    • Divided into network and host portions
    • Classes: A, B, C, D, E
    • Private address ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
  2. IPv6 (Internet Protocol version 6):
    • 128-bit address (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334)
    • Created to address IPv4 address exhaustion
    • Features improved security and routing efficiency
  3. Subnet Mask:
    • Defines which portion of an IP address is the network address
    • Example: 255.255.255.0 (or /24 in CIDR notation)

Network Security

  1. Threats:
    • Viruses, worms, trojans
    • Phishing attacks
    • Denial of Service (DoS) attacks
    • Man-in-the-middle attacks
    • Ransomware
  2. Security Measures:
    • Firewalls: Monitor and filter network traffic
    • Antivirus Software: Detect and remove malicious software
    • Encryption: Protect data during transmission
    • VPN (Virtual Private Network): Secure remote access
    • Authentication: Verify user identities
    • Access Control: Restrict access to resources

Understanding computer networks is essential in today’s interconnected world, providing the foundation for how devices communicate and share information across various scales and distances.

Complete Chapter-wise Hsslive Plus One Computer Application Notes

Our HSSLive Plus One Computer Application Notes cover all chapters with key focus areas to help you organize your study effectively:

  1. Chapter 1 Fundamentals of Computer
  2. Chapter 2 Components of the Computer System
  3. Chapter 3 Principles of Programming and Problem Solving
  4. Chapter 4 Getting Started with C++
  5. Chapter 5 Data Types and Operators
  6. Chapter 6 Introduction to Programming
  7. Chapter 7 Control Statements
  8. Chapter 8 Computer Networks
  9. Chapter 9 Internet
  10. Chapter 10 IT Applications

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