🔗

Understanding Network Hardware Components

May 19, 2025

Network Hardware - Cambridge (CIE) IGCSE ICT Revision Notes 2021

Routers

  • Definition: A router is responsible for routing data packets between different networks.
  • Functionality:
    • Connects Local Area Networks (LAN) to the wider internet (WAN).
    • Manages and prioritizes data traffic to maintain connections' stability.
    • Assigns IP addresses to devices on the network.
    • Example: Directing internet traffic to devices within a home network.

Data Packets

  • Components:
    • Header: Contains source and destination IP addresses, packet number, and error checks.
    • Payload: The actual data being transported.
    • Trailer: May contain additional security information and end of packet notification.

IP Addresses

  • Definition: Unique identifiers for devices communicating over the Internet (WAN).
  • Types:
    • IPv4: Comprises 4 blocks of numbers, total of 32 bits.
      • Provides over 4 billion unique addresses.
    • IPv6: Comprises 8 blocks of hexadecimal digits, total of 128 bits.
      • Provides over one billion unique addresses per person globally.

Network Interface Card (NIC)

  • Purpose: Essential for connecting a computer to a network.
  • Types: Can be wired or wireless.

Hubs

  • Function: Connects multiple devices in a network.
  • Characteristic: Sends all data received to all connected devices, leading to potential inefficiencies and security issues.

Switches

  • Function: Connects multiple devices on a network but only sends data to the intended device.
  • Efficiency: Uses a lookup table to forward data based on MAC addresses.

MAC Addresses

  • Definition: Unique identifiers for devices communicating over a local area network (LAN).
  • Characteristics:
    • Static and do not change.
    • 12 hexadecimal digits (48 bits), usually grouped in pairs.

Bridges

  • Function: Connects two local area networks (LANs) to form a larger network.
  • Characteristic: Different from switches and hubs as they only connect LANs.

Worked Example

  • Difference between a switch and a hub:
    • Switch: Forwards data packets based on destination MAC address.
    • Hub: Broadcasts incoming packets to all connected devices.